JP2015203201A - Design method of cast-in-place pile, design program, storage medium, design system of cast-in-place pile and flexural bearing force calculation method of cast-in-place pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To design an anchorage force of an anchorage part in a desired size.SOLUTION: A design method of a cast-in-place pile 10 for winding a steel pipe 18 on a pile head part 11a of a pile body 11, and includes a process of setting an anchorage method of the steel pipe and an inner structure part 20 in an upper end part and a lower end part of at least the steel pipe, a process of calculating anchorage force in the upper end part and the lower end part of the desired steel pipe based on a minimum value of the anchorage force with the inner structure part to the compression side and the tension side in the upper end part and the lower end part of the steel pipe, a process of making a correlation curve for the steel pipe for indicating the relationship between axial force and the bending moment based on the anchorage force calculated by the anchorage force calculation process, a process of making an accumulation strength correlation curve by superposing the correlation curve for the steel pipe on a correlation curve for an inner structure for indicating the relationship between the axial force and the bending moment of the inner structure part of the steel pipe and a process of determining a specification of an anchorage part 26 between the steel pipe and the inner structure part capable of securing the anchorage force by the anchorage method by using the accumulation strength correlation curve.

Description

  The present invention relates to a design method for a cast-in-place pile in which a steel pipe is wound around a pile head, a design program, a storage medium, and a cast-in-place pile design system.

  A cast-in-place pile is formed by drilling a pile hole from the ground surface in the ground, placing a reinforcing member such as a reinforcing bar cage in the pile hole, and then placing concrete. For this reason, it is possible to increase the diameter and length of the pile compared to a ready-made pile that is driven into the ground by a pile manufactured at the factory, and is used when constructing foundations that require a large bearing capacity. . In order to improve the earthquake resistance of cast-in-place piles, steel pipes are wound around the pile heads of cast-in-place piles, and earthquake-resistant cast-in-place piles that ensure the bending and shear strength of piles, that is, pile head cast-in-placed concrete cast piles It is used. The pile head cast-in-place concrete pile has a structure in which the upper part of the pile is a steel pipe concrete structure (part) or a steel pipe reinforced concrete structure (part) and the lower part is a reinforced concrete structure (part).

  When the bending moment is applied, the steel pipe winding part of the pile head steel pipe winding cast-in-place concrete pile is the same as the steel pipe if the neutral axis of the internal structure part such as internal concrete or internal reinforced concrete coincides. If the internal structure is integrated, a large bending strength can be achieved by the generalized cumulative strength formula. That is, in order to exert a large bending strength at the steel tube winding portion, it is necessary to improve the integrity of the steel tube and the internal structure portion. In order to integrate the steel pipe and the internal structure part, there is a KCTB method in which a steel pipe concrete pile is made by installing a steel pipe with an internal rib on the head of the cast-in-place pile. However, the ribbed steel pipe used in the KCTB method has a configuration in which ribs are provided in a spiral shape on the entire inner peripheral surface. The problem is poor procurement.

  For this reason, as a pile head steel pipe winding cast-in-place concrete pile, the thing using the structure which uses the flat steel pipe which does not provide a rib in the whole internal peripheral surface of a steel pipe is developed. In this case, since the joint part of the upper steel pipe concrete part using a flat steel pipe and the lower reinforced concrete part may become a weak part at the time of an earthquake, as a prior art which reinforces the said joint part reliably, patent document 1 Is disclosed. Further, Patent Document 2 is disclosed as a prior art that enables slip transmission by preventing slippage between a flat steel pipe and internal concrete.

  Further, in Non-Patent Documents 1 to 3, in the composite cross-section column made of steel frame and concrete, the bending strength of the composite cross-section column is changed when the fixing force at the end of the steel frame is changed without the adhesion between the steel frame and the concrete. In addition to clarifying the scope of application of the generalized cumulative intensity formula, what design formula should be used when it is impossible to apply is examined. And 1) When the anchoring force at the end of the steel frame is greater than the yield axial force of the steel frame, the bending strength of the composite section column becomes a large bending strength according to the generalized cumulative strength formula. 2) The anchoring force at the end of the steel frame is the yield strength of the steel frame When the axial force is smaller, the bending strength of the composite cross-section column is smaller than that of 1). 3) Furthermore, as a special case of 2), when there is no fixing force at the end of the steel frame, It is disclosed that the bending strength is smaller than that of 2), that is, the bending strength of the composite cross-section column is affected by the fixing force of the steel frame end.

JP 2011-074569 A JP 2006-138095 A

"The ultimate bending strength of composite cross-section columns-Consideration based on the theoretical formula of cumulative strength-" (Abstracts of Architectural Institute of Japan Conference (China), 1113 to 1114, October 1990) "Bending ultimate strength of composite section columns -Consideration by cumulative strength formula-" (The Architectural Institute of Japan Kinki Branch Research Report, 85-88, 1990) "The ultimate bending strength and cumulative strength formula of the composite section column" (Structural Engineering Papers, Vol. 37B, pages 427-435, March 1991)

  Non-Patent Documents 1 to 3 describe a composite cross-section column made of steel and concrete, but when this idea is applied to a steel pipe winding portion of a pile head steel pipe winding cast-in-place concrete pile, the bending strength of the steel pipe winding portion is This is considered to be affected by the fixing force between the steel pipe and its internal structure at the upper and lower ends of the steel pipe. For this reason, in order to exert a large bending strength in the steel tube winding portion, it is necessary to increase the fixing force in the fixing portion provided in the vicinity of the upper end portion and the lower end portion of the steel pipe.

  However, if fixing members such as ribs are provided more than necessary when increasing the fixing force between the inner peripheral surface of the steel pipe and the internal structure portion in the fixing part, the fixing force is excessively overdesigned, resulting in an uneconomical design. End up. On the other hand, unless the fixing force necessary for the fixing portion is obtained, the bending strength of the wound steel pipe portion cannot be sufficiently exhibited. That is, when designing a pile head cast-in-place concrete pile, it is necessary to calculate the bending strength of the steel pipe winding part in consideration of the fixing force in the fixing part.

  Non-Patent Documents 1 to 3 mention that the bending strength of the composite section column is affected by the fixing force at the end of the steel frame in the composite section column made of steel and concrete, but the steel pipe and its internal structure There is no mention about designing the pile head cast-in-place concrete pile considering the fixing power with the part. Patent Document 1 mentions that the joint portion between the upper steel pipe concrete portion and the lower reinforced concrete portion is reliably reinforced, but considering the fixing force between the steel pipe and its internal structure portion, No reference is made to calculating the bending strength of the part. Further, Patent Document 2 mentions that stress transmission is possible by preventing slippage between a flat steel pipe and concrete, but considering the fixing force between the steel pipe and its internal structure portion, No reference is made to calculating the bending strength of the part.

  The present invention has been made in view of the above problems, and is optimal for external forces such as earthquakes by calculating the bending strength of the steel tube winding part based on the fixing force between the steel pipe and the internal structure part in the fixing part. It is an object of the present invention to provide a new and improved cast-in-place pile design method, a design program, a storage medium, and a cast-in-place pile design system capable of designing specifications of various anchoring portions.

  One aspect of the present invention is a design method of a cast-in-place pile in which a steel pipe is wound around a pile head of the pile body including at least a bending strength calculation step of calculating a bending strength of the pile body, the bending strength The calculation step includes a setting step for setting a fixing method between the steel pipe at least at the upper end portion and the lower end portion of the steel pipe and an internal structure portion made of either internal concrete or internal reinforced concrete provided in the steel pipe, and the steel pipe The upper end of the desired steel pipe based on the minimum value of the fixing force with the internal structure portion with respect to the compression side at the upper end portion and the lower end portion and the minimum value with the internal structure portion with respect to the tension side A fixing force calculating step for calculating a fixing force at the lower end portion and the fixing force calculating step, and based on the fixing force at the compression side and the tension side calculated at the fixing force calculating step, A correlation curve creating process for creating a steel pipe correlation curve showing the relationship between the axial force and bending moment of the steel pipe part, and an internal structure correlation showing the relation between the axial force and bending moment of the internal structure part of the steel pipe The internal structure correlation curve creating step for creating a curve; and the cumulative strength correlation curve creating step for creating a cumulative strength correlation curve by accumulating the steel structure correlation curve to the internal structure correlation curve, and bending strength In the subsequent process of the calculation process, the cumulative strength correlation curve is used to determine the specifications of the fixing part between the steel pipe and the internal structure part that can secure the fixing force by the fixing method set in the setting process. A fixing unit specification determining step is included.

  According to one aspect of the present invention, after calculating a fixing force of a desired size at the upper end and the lower end of the steel pipe in the fixing force calculating step, the steel pipe correlation curve created based on the fixing force and the cumulative force are calculated. After determining the appropriateness of the fixing force using the intensity correlation curve, it is possible to determine the specifications of the fixing unit that can ensure the desired fixing force.

  At this time, in one aspect of the present invention, a bending stress calculation step for calculating a bending stress generated in the pile body, and a bending stress examination step for examining the validity of the bending stress with respect to the bending strength after the bending strength calculation step. The bending stress examination step includes a bending stress value determination step of determining whether or not the bending stress at the minimum and maximum values of the axial force during an earthquake is included in the cumulative strength correlation curve. It is good as well.

  In this way, the specifications of the fixing unit for securing the fixing force of a desired size are determined based on the appropriateness of the bending stress with respect to the bending strength calculated in the bending strength calculation step. It is possible to reliably design a fixing unit that ensures safety.

  In one aspect of the present invention, the bending stress examination step includes the bending stress at the minimum value and the maximum value when the bending stress is included in the cumulative strength correlation curve in the bending stress value determination step. In the test ratio determination step for determining whether or not the test ratio, which is the ratio of the bending strength to the bending strength, and the test ratio determination step, the test ratio at the maximum value or the minimum value is not an appropriate value. An over / under determination step in which it is determined whether the verification ratio is excessive or small when the determination ratio is determined to be excessive in the over / under determination step. It is good also as returning to the steel pipe winding specification selection process which selects the specification of the said steel pipe which has a stage before a stress calculation process and the said bending strength calculation process.

  In this way, when the verification ratio calculated based on the fixing force calculated in the bending strength calculation step is not an appropriate value, the fixing portion can be efficiently redesigned.

  In one aspect of the present invention, when it is determined in the bending stress value determination step that the bending stress at the maximum value or the minimum value is not included in the cumulative intensity correlation curve, the minimum value is determined. When it is determined that the bending stress is not included in the cumulative strength correlation curve, the tensile side comparison step of comparing the magnitude relationship between the tensile yield axial force of the steel pipe and the fixing force with respect to the tensile force And when it is determined that the bending stress at the maximum value is not included in the cumulative strength correlation curve, the magnitude relationship between the compression yielding axial force of the steel pipe and the fixing force with respect to the compression force It is good also as shifting to the compression side comparison process which compares these.

  If it does in this way, when the stress which generate | occur | produced in the pile body is larger than the cumulative strength which shows the yield strength of a pile body, the cause of the malfunction can be examined efficiently.

  In one aspect of the present invention, when it is determined in the tension side comparison step that the tensile yield axial force of the steel pipe is smaller than the fixing force with respect to the tensile force, it is necessary to increase the tensile yield axial force. It is good also as shifting to the tension | pulling side cost comparison process which examines the magnitude relationship with the cost required to enlarge the bending proof stress of the said steel pipe in case a cost and axial force are 0.

  In this way, it is possible to redo the design from a more suitable process after considering the necessary cost for eliminating the problem of the calculated fixing force.

  In one aspect of the present invention, when it is determined in the compression side comparison step that the compression yield axial force of the steel pipe is larger than the fixing force with respect to the compression force, it is necessary to increase the compression yield axial force. It is good also as shifting to the compression side cost comparison process which examines the magnitude relationship with the required cost for enlarging the bending proof stress of the said steel pipe in case a cost and axial force are zero.

  In this way, it is possible to redo the design from a more suitable process after considering the necessary cost for eliminating the problem of the calculated fixing force.

  Moreover, the other aspect of this invention is a design program for making a computer perform the design method of the cast-in-place pile in any one mentioned above.

  According to the other aspect of the present invention, the fixing force of the fixing portion between the steel pipe wound around the pile head and the internal structure portion can be designed to a desired size in accordance with such a design program.

  Another aspect of the present invention is a storage medium in which a computer-readable design program for causing a computer to execute any one of the above-described cast-in-place pile design methods is stored.

  According to another aspect of the present invention, the fixing force of the fixing portion between the steel pipe wound around the pile head and the internal structure portion can be designed to a desired size in accordance with the design program stored in the storage medium. .

  Another aspect of the present invention is a cast-in-place pile design system in which a steel pipe is wound around a pile head of a pile body, and stores at least predetermined data relating to the design of the cast-in-place pile Minimum value of fixing force with the internal structure portion made of either internal concrete or internal reinforced concrete on the compression side at least at the upper end portion and the lower end portion of the steel pipe, and minimum fixing force with the internal structure portion on the tension side A calculation unit that calculates a fixing force at the upper end portion and the lower end portion of the desired steel pipe based on the value; and included in the calculation unit, at least the steel pipe at the upper end portion and the lower end portion of the steel pipe, and the steel pipe A setting unit that sets a fixing method with an internal structure portion provided inside, and the steel included in the pile body, which is included in the calculation unit, based on the fixing force on the compression side and the tension side A correlation curve creating section for creating a steel pipe correlation curve showing the relationship between the axial force of the part and the bending moment, and the calculation part included in the correlation section for the steel pipe, and the relation between the axial force and the bending moment of the internal structure part of the steel pipe A cumulative strength correlation curve creating unit that creates the cumulative strength correlation curve by accumulating the steel pipe correlation curve to the internal structure correlation curve shown, and the fixing unit using at least the cumulative strength correlation curve. A fixing force determination unit that examines the validity of the force, and a fixing unit specification determination unit that is included in the calculation unit and determines the specification of the fixing unit between the steel pipe and the internal structure portion that can secure at least the fixing force; It is characterized by providing.

  According to another aspect of the present invention, the calculation unit calculates a fixing force of a desired size at the upper end and the lower end of the steel pipe, and then uses a cumulative intensity correlation curve created based on the fixing force. Then, after determining the appropriateness of the fixing force, it is possible to efficiently design a fixing unit that can secure a fixing force of a desired size.

  At this time, in one aspect of the present invention, the storage unit includes, as the predetermined data, at least soil soil data on which the cast-in-place pile is provided, specification data relating to components of the pile body, and the cast-in-place pile The past design performance data may be stored in a database.

  In this way, since the optimum value of the fixing force at the upper end and the lower end of the steel pipe can be set based on the predetermined data relating to the design of the cast-in-place pile, the fixing unit that can ensure the fixing force of a desired size Can be designed efficiently.

  As described above, according to the present invention, the fixing force in the fixing portion of the steel pipe is calculated according to the bending strength required by the steel tube winding portion, and the cumulative strength correlation curve created based on the fixing force is calculated. Since the adequacy of the fixing force is used to determine the fixing force, it is possible to efficiently design a fixing unit that can secure the fixing force. For this reason, it is possible to efficiently design the specification of the fixing portion that does not become overspec.

It is a longitudinal cross-sectional view explaining the structure of the cast-in-place pile designed by the design method of the cast-in-place pile which concerns on one Embodiment of this invention. It is a block diagram which shows the whole structure of the design system of the cast-in-place pile which concerns on one Embodiment of this invention. It is a flowchart which shows the outline of the design method of the cast-in-place pile which concerns on one Embodiment of this invention. It is a flowchart which shows the detail of the bending strength calculation process included in the design method of the cast-in-place pile which concerns on one Embodiment of this invention. (A) thru | or (E) are explanatory drawings which show an example of the correlation curve preparation process for steel pipes contained in the design method of the cast-in-place pile which concerns on one Embodiment of this invention. (A) thru | or (C) is explanatory drawing which shows an example of the cumulative intensity correlation curve creation process included in the design method of the cast-in-place pile concerning one Embodiment of this invention. (A) thru | or (C) is explanatory drawing which shows an example of the cumulative intensity correlation curve creation process included in the design method of the cast-in-place pile concerning one Embodiment of this invention. It is a flowchart which shows the detail of the bending stress examination process included in the design method of the cast-in-place pile which concerns on one Embodiment of this invention. It is explanatory drawing which shows an example of the bending stress examination process included in the design method of the cast-in-place pile which concerns on one Embodiment of this invention. It is a flowchart which shows the outline of the design method of the cast-in-place pile which concerns on other embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The present embodiment described below does not unduly limit the contents of the present invention described in the claims, and all the configurations described in the present embodiment are essential as means for solving the present invention. Not necessarily.

  First, the outline of the structure of a cast-in-place pile designed by the cast-in-place pile design method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view illustrating a configuration of a cast-in-place pile designed by a design method for cast-in-place pile according to an embodiment of the present invention.

  As shown in FIG. 1, the cast-in-place pile 10 according to the present embodiment is an earthquake-resistant cast-in-place pile in which a steel pipe 18 is wound around a pile head 11 a of the pile body 11, that is, a pile-head steel tube-wound cast-in-place concrete pile. is there. In other words, the cast-in-place pile 10 according to the present embodiment includes a steel pipe reinforced concrete portion 12 serving as a pile head steel tube winding portion formed on the upper side and a reinforced concrete portion 14 formed on the lower side. It is a rolled cast-in-place concrete pile. Moreover, the cast-in-place pile 10 of this embodiment is a bottom expansion pile in which the bottom part 14b of a substantially truncated cone shape is provided in the lower part side of the reinforced concrete part 14. FIG. In the cast-in-place pile 10, the SRC type in which the main reinforcement 16 made of steel of the reinforced concrete portion 14 is provided so as to penetrate the steel pipe reinforced concrete portion 12, and the main reinforcement 16 made of steel of the reinforced concrete portion 14 does not penetrate the steel pipe concrete portion. There is SC type.

  As shown in FIG. 1, the steel pipe reinforced concrete pile part 12 used as the pile head steel pipe winding part is mainly comprised by the substantially cylindrical steel pipe 18 and the internal reinforced concrete 20 with which the inner space is filled. In the present embodiment, as the steel pipe 18, for example, a flat steel pipe having a diameter of about 700 mm to 2500 mm and a flat inner peripheral surface is used. Thus, by installing the steel pipe 18 on the pile head 11a side of the cast-in-place pile 10, the shear strength and the bending strength can be improved and a pile body excellent in economy and procurement power can be obtained.

  In addition, in FIG. 1, although the internal structure part provided in the inner space of the steel pipe 18 shows the SRC type pile head steel pipe winding cast-in-place concrete pile as the cast-in-place pile 10, the SC type and In this case, the internal structure portion provided in the inner space of the steel pipe 18 becomes the internal concrete. In addition, the “internal structure portion” referred to in the present specification indicates the internal reinforced concrete 20 or the internal concrete provided in the inner space from the upper end portion 18 a to the lower end portion 18 b of the steel pipe 18.

  In order to sufficiently exhibit the bending proof strength of the steel pipe reinforced concrete portion 12 on which the steel pipe 18 is attached, a fixing portion 26 for securing the fixing force between the steel pipe 18 and the internal reinforced concrete 20 is provided. In the present embodiment, as shown in FIG. 1, fixing portions 26 a and 26 b are provided on the upper end portion 18 a and the lower end portion 18 b of the steel pipe 18 as the fixing portion 26.

  A plurality of pile head fixing bars 22 are attached to the fixing portion 26 a on the outer peripheral surface of the upper end portion 18 a of the steel pipe 18 by welding or the like, and are provided so as to protrude upward from the steel pipe 18. Moreover, these pile head fixing muscles 22 are entirely covered with a pile cap 24. Thus, by providing the pile head fixing muscle 22 and the pile cap 24 that function as the fixing portion 26a, the upper end portion 18a of the steel pipe 18 and the internal structure portion are provided via the pile head fixing muscle 22 and the pile cap 24. Fixation with the internal reinforced concrete 20 is achieved.

  In this embodiment, the fixing force in the fixing part 26a of the steel pipe 18 and the internal reinforced concrete 20 is set to a desired magnitude by changing the number of pile head fixing bars 22. That is, the fixing force at the upper end portion 18a of the steel pipe 18 can be increased by increasing the number of the pile head fixing bars 22, while the fixing force at the upper end portion 18a of the steel pipe 18 can be increased by decreasing the number of the pile head fixing bars 22. Can be lowered.

  In this embodiment, the pile head fixing bar 22 is provided as a fixing member for securing the fixing force of the fixing unit 26a. However, a member other than the pile head fixing bar 22 may be used. For example, the protruding ring 28 exemplified as a fixing member of the fixing unit 26b described later may be used, or a fixing member other than the protruding ring 28 may be used. That is, if the upper end portion 18a of the steel pipe 18 and the internal structure portion 20 can be fixed, for example, toward the inner peripheral surface side of the upper end portion 18a of the steel pipe 18 such as a plate-like or rod-like steel material or bolt. A member having a protruding configuration may be applied as the fixing member. Further, a plurality of fixing members in the fixing unit 26a may be used together. For example, the pile head fixing bars 22 and protrusion rings, plate-like or rod-like steel materials, etc. may be used together.

  Further, regarding the specification for setting the fixing force of the fixing portion 26a, in addition to the method of changing the number of pile head fixing muscles 22, a method of changing the diameter, length, strength, etc. of the pile head fixing muscles 22 and a pile cap You may take the method of changing the concrete strength of 24. Further, even when a fixing member such as a projecting ring is provided as a fixing member for securing the fixing force of the fixing unit 26a, a technique or a cast-in-place pile for changing the number, the size, the shape, etc. of the fixing member. A method of changing the concrete strength of 10 may be adopted.

  On the other hand, during an earthquake, the horizontal force and the variable axial force from the upper structure are input to the pile cap 24. As a result, a bending moment or a shearing force acts on the cast-in-place pile 10. When the upper end portion 18a of the steel pipe 18 is fixed to the pile cap 24 by the pile head fixing bar 22, the bending moment and the shearing force are generally maximized at the pile head and gradually decrease downward. Therefore, in this embodiment, in order to counter such bending moment and shearing force, the steel pipe 18 is wound around the pile head 11a of the pile body 11, and the bending strength and shear strength of the pile body 11 are increased. Yes.

  In this embodiment, the case where the upper end portion 18a of the steel pipe 18 is fixed to the pile cap 24 is taken up. However, the cast-in-place pile 10 designed by the design method according to the embodiment of the present invention is It is not limited to the fixed type. That is, for example, in a cast-in-place pile having a configuration in which the upper end portion 18a of the steel pipe 18 is in a semi-fixed state, a configuration in which rotation is not restricted by a pin or the like, and a configuration that is movable by a special device such as a seismic isolation device The cast-in-place pile design method according to an embodiment of the present invention is also applicable.

  In the present embodiment, in order to secure the fixing force between the steel pipe 18 and the internal reinforced concrete 20, a protruding ring 28 made of steel or the like is welded to the inner peripheral surface side of the lower end portion 18b of the steel pipe 18 in the fixing portion 26b. It is attached by etc. Thus, by providing the projection ring 28, the lower end portion 18b of the steel pipe 18 and the internal reinforced concrete 20 can be fixed via the fixing portion 26b.

  Furthermore, in the present embodiment, the fixing force of the fixing unit 26b is set to a desired magnitude by changing the number of the protrusion rings 28. That is, the fixing force of the fixing unit 26b is increased by increasing the number of the protruding rings 28, and is decreased by decreasing the number of the protruding rings 28.

  In this embodiment, the protrusion ring 28 is provided as a fixing member for securing the fixing force of the fixing portion 26b. However, a member other than the protrusion ring 28 may be used. That is, if the fixing unit 26b can be fixed, for example, a member that protrudes toward the inner peripheral surface of the steel pipe 18 such as a plate-like or rod-like steel material or bolt is used as the fixing member. Applicable.

  In addition to the method of changing the number of fixing members such as the projection ring 28, the specification for setting the fixing force of the fixing unit 26b is not limited to the method of changing the size and shape of the cross section of the fixing member. A method of changing the concrete strength of the pile 10 may be adopted. Further, as a specification for setting the fixing force of the fixing unit 26b, the number, shape, and the like of these may be changed by using the projection ring 28 and fixing members of various modes such as plate-shaped or rod-shaped steel materials in combination.

  In this embodiment, the design method of the cast-in-place pile 10 by the design system 100 (refer FIG. 2) demonstrated below is implemented, and the optimal value of the fixing force in the fixing | fixed part 26a, 26b is calculated | required more efficiently and reliably. ing. The design system 100 can efficiently design the fixing units 26a and 26b that can secure the fixing force at the optimum value.

  Next, the structure of the cast-in-place pile design system according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a block diagram illustrating the overall configuration of a cast-in-place pile design system according to an embodiment of the present invention.

  As shown in FIG. 2, the cast-in-place pile design system 100 according to the present embodiment accesses a database server having a database in which a computer 101 held by a user stores predetermined data related to the design of the cast-in-place pile 10. The optimum fixing force in the fixing units 26a and 26b is obtained while performing the search process. That is, the cast-in-place pile design system 100 according to the present embodiment is used to determine the specifications of the fixing units 26a and 26b for securing the fixing force.

  In the present specification, the “user” refers to a person who performs the design or construction work of the cast-in-place pile 10. The “computer” refers to an information terminal provided with an arithmetic device capable of various arithmetic processes such as a super computer, a general-purpose computer, an office computer, a control computer, a personal computer, and a portable information terminal.

  In the process of designing the cast-in-place pile 10, the cast-in-place pile design system 100 of the present embodiment sets the fixing force in the fixing portions 26a, 26b for fixing the steel pipe 18 and the internal structure portion 20 to a desired size. Used when. The design system 100 calculates the optimum fixing force by the computer 101 based on predetermined data relating to the design of the cast-in-place pile 10, and fixes the number of protrusion rings 28 installed based on the fixing force. The specifications of the unit 26 are determined. Note that the configuration of the design system 100 is not limited to FIG. 2, and various modifications such as omitting some of the components or adding other components are possible.

  As shown in FIG. 2, the computer 101 includes a storage unit 102, a CPU (Central Processing Unit) 110, an input unit 120, an output unit 122, a communication unit 124, a ROM (Read Only Memory) 108, and a RAM (Random access Memory) 106. , And a storage medium 104, and these components are electrically connected to each other via a system bus 125. Therefore, the CPU 110 accesses the storage unit 102, ROM 108, RAM 106, and storage medium 104, grasps the operation state of the input unit 120, outputs data to the output unit 122, and transmits / receives various information to / from the Internet 126 via the communication unit 124. Etc.

  The storage unit 102 is a database server having a function of storing at least predetermined data relating to the design of the cast-in-place pile 10. In this embodiment, the memory | storage part 102 is the structure of pile bodies 11 such as the soil soil data, the steel pipe 18 and the internal structure part 20, the main reinforcement 16, SRC, SC at least as the predetermined data. The specification data related to the elements and the past design performance data of the cast-in-place pile 10 are stored in a database.

  Since the fixing force can be set to a desired magnitude based on the predetermined data relating to the design of such cast-in-place pile 10, the specifications of fixing portions 26a and 26b that can secure the fixing force can be determined efficiently. It becomes like this. Further, by accumulating these data in the storage unit 102, when the cast-in-place pile 10 is provided at another construction site, the fixing data having a desired size is obtained using the accumulated data stored in the storage unit 102. The specifications of the fixing portions 26a and 26b that can ensure the above are required with higher accuracy.

  The CPU 110 has a function of controlling the operation of each component included in the design system 100 in accordance with data received via the communication unit 124 and various programs stored in the ROM 108 and the storage medium 104. In addition, the CPU 110 has a function of appropriately storing necessary data and the like in the RAM 106 that temporarily stores these various processes.

  In the present embodiment, the CPU 110 performs arithmetic processing by a computer based on predetermined data related to the design of the cast-in-place pile 10 and performs various arithmetic processing necessary for obtaining a fixing force having a desired size. Function as. That is, the CPU 110 performs a calculation process on the computer 101 based on at least the predetermined data, calculates a fixing force having a desired size, and then designs the fixing units 26a and 26b that can secure the fixing force. Have Specifically, the CPU 110 fixes based on the minimum value of the fixing force with the internal structure portion 20 with respect to the compressive force (compression side) and the tensile force (tensile side) at least at the upper end portion 18a and the lower end portion 18b of the steel pipe 18. It has a function of calculating the fixing force in the sections 26a and 26b.

  In the present embodiment, the CPU 110 includes a setting unit 112, a correlation curve creation unit 113, a determination unit 114, and a determination unit 116. In the present specification, the “predetermined data” related to the design of the cast-in-place pile 10 is at least soil data of the ground where the cast-in-place pile 10 is provided, the steel pipe 18 and the internal structure portion 20, the main reinforcement 16, SRC, It refers to various data such as specification data relating to the components of the pile body 11 such as SC and past design performance data of the cast-in-place pile 10. That is, the “predetermined data” refers to various data necessary for determining the fixing force of the fixing portions 26a and 26b and determining the specifications in the process of designing the cast-in-place pile 10, and determining the pile type. It is also used to do.

  In the process of designing the cast-in-place pile 10 by the design system 100, the setting unit 112 has a function of setting a fixing method and its specification by the fixed portions 26a, 26b based on predetermined data relating to the design of the cast-in-place pile 10. Have. Examples of the fixing method include a method of attaching a ring-shaped protrusion to the inner surface of the steel pipe, a method of fixing a deformed reinforcing bar on the outer peripheral surface of the steel pipe 18 in the axial direction of the steel pipe, and fixing it via pile cap concrete. The specifications of the fixing units 26a and 26b include, for example, the number, size, shape, pitch interval, and the like of fixing members such as the pile head fixing bars 22 and the protrusion ring 28.

  The correlation curve creation unit 113 is a correlation curve showing the relationship between the axial force (N) and the bending moment (M) of the steel pipe 18 or the steel pipe winding part 12 used for calculating a fixing force having a desired size. It has a function of creating an NM curve.

  In the present embodiment, the correlation curve creating unit 113 determines the relationship between the axial force (N) and the bending moment (M) of the steel pipe 18 portion of the pile body 11 based on the compression force and the fixing force of the tensile force of the steel pipe 18. It has a function as a steel pipe correlation curve creating section for creating the steel pipe correlation curve shown. In addition, the correlation curve creating unit 113 is an internal showing the relationship between the axial force (N) of the reinforced concrete (RC) part or the concrete (C) part and the bending moment (M) of the pile body 11 as the internal structure part of the steel pipe 18. It has a function as a correlation curve creation unit for internal structure that creates a correlation curve for structure. Furthermore, the correlation curve creation unit 113 also has a function as a cumulative strength correlation curve creation unit that creates a cumulative strength correlation curve by accumulating the steel pipe correlation curve S to the internal structure correlation curve.

  The determination unit 114 has a function of determining validity of various data set based on predetermined data related to the design of the cast-in-place pile 10 in the process of designing the cast-in-place pile 10 with the design system 100. In the present embodiment, the determination unit 114 has a function as a fixing force determination unit that examines the validity of the fixing force in the fixing units 26a and 26b using at least the cumulative intensity correlation curve.

  The determination unit 116 has a function of determining optimum values of various data set based on predetermined data relating to the design of the cast-in-place pile 10. In the present embodiment, the determination unit 116 has a function of determining the specifications of the fixing units 26 a and 26 b based on the determination result of the determination unit 114.

  Specifically, the determining unit 116 changes the number, length, and cross-sectional size of the pile head fixing bars 22 provided on the outer peripheral surface of the upper end portion 18a of the steel pipe 18 to gradually change the steel pipe 18 in the fixing unit 26a. The fixing force is determined so as to be changed to a desired size. Further, the determining unit 116 changes the length and number of the fixing members such as the projection ring 28, the rib member, the bolt, and the welded rebar on the inner peripheral surface of the lower end portion 18b of the steel pipe 18 to gradually increase the steel pipe in the fixing unit 26b. The fixing force of 18 is determined so as to be changed to a desired size.

  The input unit 120 has a function of inputting various data such as predetermined data related to the design of the cast-in-place pile 10, and for example, a mouse, a keyboard, a touch panel, or the like is used. In the present embodiment, the input unit 120 inputs characters and various data when the setting unit 112, the correlation curve creation unit 113, the determination unit 114, and the determination unit 116 are operated, for example.

  Further, in the present embodiment, the input unit 120 obtains a required amount of fixing force in the fixing units 26a and 26b based on at least predetermined data related to the design of the cast-in-place pile 10, and the necessary data, etc. Also used when entering. That is, the input unit 120 is used when inputting various data stored in the storage unit 102 or when inputting various data for determining the fixing power of the fixing units 26a and 26b.

  The output unit 122 has a function of outputting a calculation result by the CPU 110, information on the storage unit 102 serving as a database, and the like. For example, a display monitor or the like is used as the output unit 122. In the present embodiment, the output unit 122 performs screen display when the setting unit 112, the correlation curve creation unit 113, the determination unit 114, and the determination unit 116 are operated, for example.

  The storage medium 104 is a medium readable by the computer 101 and has a function of storing programs, data, and the like. The function of the storage medium 104 can be realized by various memories such as an optical disk (CD, DVD), HDD, or USB. The storage medium 104 stores a design program for realizing the function of each component of the design system 100 of the present embodiment so that the computer 101 can read it.

  For this reason, each process in the design method of the cast-in-place pile 10 which concerns on this embodiment by the said design program comes to be performed by implement | achieving the function of each component of the said design system 100. FIG. In addition, the detail of the design method of the cast-in-place pile 10 based on this embodiment performed by the said design program is mentioned later.

  As described above, according to the design system 100 of the present embodiment, based on the predetermined data relating to the design of the cast-in-place pile 10, the fixing force of a desired size in the fixing units 26a and 26b is calculated, and then The validity of the fixing force can be determined using the cumulative intensity correlation curve created based on the fixing force. Then, after considering the appropriateness of the fixing force, the fixing portions 26a and 26b that can secure the fixing force can be designed efficiently.

  For this reason, when designing the fixing portions 26a and 26b, the fixing portions 26a and 26b capable of securing a fixing force that does not cause over-spec can be surely designed. Moreover, in addition to the specification setting of the steel pipe 18 and the specification setting of the internal structure part 20 of the steel pipe 18, the fixing force of the steel pipe 18 can be set to an appropriate value according to the bending strength required by the steel pipe winding part. Thus, the more economical pile head steel pipe winding cast-in-place pile 10 can be designed by setting the specification of the fixing | fixed part 26a, 26b provided in the edge parts 18a, 18b of the steel pipe 18 to an appropriate value. .

  Next, a method for designing a cast-in-place pile according to an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a flowchart showing an outline of a method for designing a cast-in-place pile according to an embodiment of the present invention.

  The design method of the cast-in-place pile 10 according to the present embodiment obtains the optimum fixing force for securing the fixing force in the fixing portions 26a and 26b between the steel pipe 18 and the internal structure portion 20, and ensures the fixing force. The main point is to determine the specifications of the fixing unit 26 for the purpose.

In the present embodiment, first, a design external force is calculated using predetermined data relating to the design method of the cast-in-place pile 10 (step S101). Specifically, the design horizontal force, normal axial force N _L , fluctuating axial force N _E , earthquake axial force minimum value N _L−E , and earthquake axial force maximum value N _{L + E} are included as the design external force. calculate. Note that the minimum value N _L-E Seismic axial force is the difference always the axial force N _L and variable axial force _{N E (N L -N E)} , the maximum value N _{L + E} Seismic axial force Is the sum (N _L + N _E ) of the constant axial force N _L and the variable axial force N _E.

  Next, ground information such as geological data at the construction site of the cast-in-place pile 10 to be designed is input (step S102). In the flowchart shown in FIG. 3, the present step S102 is performed after the step S101. However, these steps S101 and S102 may be performed simultaneously or the step S102 may be performed before the step S101.

  When the calculation of the design external force and the input of ground information are completed, the initial design conditions for designing the cast-in-place pile 10 such as the construction method, the tip pile diameter, and the pile length are selected (step S103). Specifically, the conditions are selected by calculating the supporting force and the pulling resistance determined from the ground on which the cast-in-place pile 10 is constructed.

  When the selection of the initial design conditions is completed, the reinforced concrete pile portion 14 formed on the lower side of the cast-in-place pile 10 such as the pile diameter, the reinforcing bar diameter, the number of reinforcing bars, the reinforcing bar arrangement diameter, the reinforcing bar material, and the concrete strength is configured. The specification of the reinforced concrete portion ((RC portion) is selected (step S104). Specifically, the specification is selected by calculating the compression strength and the tensile strength determined from the pile body 11.

  If the specification of RC part is selected, next, the specification selection of the steel pipe winding part (SRC part, SC part) which comprises the steel pipe reinforced concrete pile part 12 formed in the upper part side of the cast-in-place pile 10 will be performed (process S105). Specifically, the selection of the steel pipe winding part specification as SRC or SC, pile diameter, steel pipe material, steel pipe length, steel pipe plate thickness, concrete strength, reinforcing bar diameter, number of reinforcing bars, reinforcing bar arrangement diameter, Select the specifications of the reinforcing bar material. And if the specification of a steel pipe winding part is selected, the number of piles and pile arrangement | positioning in the construction place of the cast-in-place pile 10 will be set next (process S106).

Next, the bending stress which generate | occur | produces in the pile body 11 is calculated using the horizontal force for design calculated by process S101 (process S107). Specifically, as the minimum value of the axial force of the pile body 11, the bending stress at the minimum value N _L-E of the axial force at earthquake and the bending stress at the maximum value N _{L + E} of the axial force at earthquake are calculated.

  Once the bending stress is calculated, the bending strength of the pile body 11 is then calculated (step S108). In the present embodiment, in the bending strength calculation step S108, a fixing force having a desired magnitude is calculated, and then a steel pipe correlation curve is created based on the fixing force. And the correlation curve for steel pipes and the correlation curve for internal structures are accumulated, and a cumulative strength correlation curve is created. The detailed description of the bending strength calculation step S108 will be described later.

  In the flowchart shown in FIG. 3, the bending strength calculation step S108 is performed after the bending stress calculation step S107. However, even if these steps S107 and S108 are performed simultaneously, the step S108 is performed before the step S107. May be.

  After the bending stress calculation step S107 and the bending strength calculation step S108 are completed, the bending stress calculated in the bending stress calculation step S107 is examined (step S109). Specifically, in the bending stress examination step S109, the validity of the bending stress with respect to the bending strength calculated in the bending strength calculation step S108 is examined.

  In this way, by examining the validity of the bending stress, the fixing portion 26a for securing the fixing force of a desired magnitude, based on the validity of the bending stress with respect to the bending strength calculated in step S108, Since the specification of 26b is determined, it is possible to reliably design the fixing units 26a and 26b that ensure further safety. In this embodiment, the bending stress examination step S109 is performed after the bending strength calculation step S108. However, the present step S109 may be skipped and the process may proceed to the next step S110. The detailed description of the bending stress examination step S109 will be described later.

  When the examination of the bending stress is completed, next, the specifications of the fixing portions 26a and 26b are determined (step S110). In the fixing unit specification determination step S110 of this embodiment, the specifications are determined so that the fixing units 26a and 26b can secure the fixing force calculated using the cumulative strength correlation curve created in the bending strength calculation step S108. That is, in the present embodiment, it is possible to design the fixing portions 26a and 26b that can secure a fixing force having a desired size. Specifically, in order to ensure the necessary fixing force, the number of protrusion rings 28 provided in the fixing portion 26b can be set to 0, 1, and 3. In addition, the specifications such as the number, diameter, length, strength, etc. of the pile head fixing muscles 22 serving as the fixing portion 26a and the concrete strength of the pile cap 24 are also determined.

  Once the specifications of the fixing portions 26a and 26b are determined, the shear stress generated in the pile body 11 by the design horizontal force and the shear strength of the pile body 11 are calculated (step 111). These shear stress and shear strength may be calculated sequentially or simultaneously.

  After calculating the shear stress and the shear strength of the pile body 11, next, the shear stress is examined (step S112). Specifically, an examination is made as to whether the shear stress is a reasonable magnitude with respect to the shear strength. In the case where the shear stress is not an appropriate magnitude in this step S112, the process returns to step S105 and starts again from the selection of the specification of the steel pipe winding portion, as shown in FIG. 3, in order to secure a more suitable shear stress.

  When the study on the shear stress is completed, the study on the settlement is performed (step S113). Specifically, the settlement condition of the pile body 11 at the construction site of the cast-in-place pile 10 is performed by simulation or the like. If it is determined in this step S113 that the subsidence conditions are not appropriate, the process returns to step S103 and starts again from the selection of the design initial conditions as shown in FIG. 3 in order to ensure a more suitable subsidence condition.

  After the examination for settlement, the pile head joints, pile caps, and foundation beams related to the pile head are finally examined (step S114), and the pile conditions such as the number of piles, pile arrangement, pile specifications, etc. A final decision is made (step S115). And the design by the design method of the cast-in-place pile 10 which concerns on this embodiment is completed.

  As described above, in the design method of the present embodiment, after calculating a suitable fixing force in the fixing portions 26a and 26b based on predetermined data related to the design of the cast-in-place pile 10, the validity thereof is examined. Thus, it is possible to efficiently design the fixing portions 26a and 26b that can secure the fixing force. Therefore, it is possible to prevent overdesign in which the fixing force of the fixing portions 26a and 26b is unnecessarily large, thereby reducing overwork and cost, and avoiding overspec when forming the fixing portions 26a and 26b. In addition, since the fixing force of the fixing portions 26a and 26b can be set to a desired size according to the type of pile, the pile diameter, the pile length, etc. according to the ground strength, the optimum and economical of the cast-in-place pile 10 Design and construction can be done.

  Next, the detail of the bending strength calculation process included in the design method of the cast-in-place pile which concerns on one Embodiment of this invention is demonstrated, using drawing. FIG. 4 is a flowchart showing details of a bending strength calculation step included in the cast-in-place pile design method according to one embodiment of the present invention.

  The bending strength calculation step S108 in the design method of the cast-in-place pile 10 according to the present embodiment includes a setting step S108-1, a fixing force calculation step S108-2, a steel pipe correlation curve creation step S108-3, and an internal structure correlation curve creation. Including the step S108-4 and the cumulative strength correlation curve creating step S108-5, the bending strength of the pile body 11 is calculated by performing these steps S108-1 to S108-5 in the order shown in FIG. Features.

  In the setting step S108-1, the fixing method of the fixing units 26a and 26b and the specifications thereof are set. As the fixing method, for example, a joining member configured to protrude in a convex shape toward the inner peripheral surface side, such as a projection ring 28, a plate-like, rod-shaped steel material, or a bolt, on the inner peripheral surface side of the steel pipe 18. Or by attaching a deformed reinforcing bar in the axial direction to the outer peripheral surface side of the steel pipe 18 and then attaching a pile cap to the distal end side of the deformed reinforcing bar. In the setting step S108-1, as the specifications of the fixing unit 26b, for example, the number of projection rings 28, the size and shape of the cross section, the pitch interval of the projection rings 28, and the like are provisionally determined, and further, the specifications of the fixing unit 26a. For example, the number, diameter, length, strength, and the like of the pile head fixing muscles 22 and the concrete strength of the pile cap 24 are temporarily determined.

  In the fixing force calculation step S108-2, the fixing forces of the fixing portions 26a and 26b provided at the ends 18a and 18b of the steel pipe 18 are calculated. Specifically, as the fixing force with respect to the compressive force, the smaller value of the fixing force (cNbu) with respect to the compressive force at the steel pipe upper end 18a and the fixing force (cNbl) with respect to the compressive force at the steel pipe lower end 18b is determined as the fixing force with respect to the compressive force (cNb). ). On the other hand, as the fixing force with respect to the tensile force, the smaller value of the fixing force with respect to the tensile force at the steel pipe upper end 18a (tNbu) and the fixing force with respect to the tensile force at the steel pipe lower end 18b (tNbl) is set as the fixing force with respect to the tensile force (tNb). To do. That is, in this step S108-2, in order to obtain the fixing force according to the bending strength required by the steel pipe winding portion, the minimum value of the fixing force with the internal structure portion 20 with respect to the compressive force at the steel pipe upper end 18a and the steel pipe lower end 18b. Based on the minimum value of the fixing force with the internal structure portion 20 against the tensile force, the temporarily determined fixing force (cNb, tNb) of the steel pipe 18 is calculated.

  In the steel pipe correlation curve creating step S108-3, the axial force (N) -bending of the steel pipe portion (S portion) in consideration of the fixing force (cNb, tNb) at the fixing portions 26a, 26b provided at the steel pipe end portions 18a, 18b. A correlation curve showing the relationship of moment (M) is created. That is, a steel pipe correlation curve indicating the relationship between the axial force N of the steel pipe portion 12 of the pile body 11 and the bending moment M is created based on the fixing force of the compressive force and the tensile force calculated in the fixing force calculation step S109-1. To do.

  Specifically, the fixing force (cNb, tNb) in the fixing portions 26a and 26b, the compression yield axial force (cNs) of the steel pipe, the tensile yield axial force (-tNs) of the steel pipe, and the steel pipe when the axial force is zero The steel pipe correlation curve (S) shown in FIGS. 5A to 5E is created based on the magnitude relationship with the bending strength (Ms). That is, in this embodiment, the fixing force (cNb, tNb), the compression yielding axial force (cNs) of the steel pipe, the tensile yielding axial force (-tNs) of the steel pipe, and the bending strength of the steel pipe when the axial force is zero ( Based on the magnitude relationship with Ms), as shown in FIGS. 5A to 5E, five types of correlation curves (S) for steel pipe are created. In other words, a plurality of correlation curves (S) for steel pipes are created based on the magnitude of the fixing force. In this embodiment, FIG. 5 (A) shows the correlation curve (S) for three steel pipes in a state where all the projection rings 28 are installed, and FIG. 5 (D) shows a part of the projection ring 28. The correlation curve (S) for steel pipes in the case of one installed pipe is shown, and FIG. 5 (E) shows the correlation curve (S) for steel pipes in the case of zero installation without the projection ring 28.

  In the internal structure correlation curve creating step S108-4, an internal structure correlation curve (RC, C) indicating the relationship between the axial force of the internal structure portion 20 of the steel pipe 18 and the bending moment is created. In the cumulative strength correlation curve creation step S108-5, the steel structure correlation curve (S) is added to the internal structure correlation curve (RC, C) to create a cumulative strength correlation curve (SRC, SC).

  That is, the relationship between the axial force (N) and the bending moment (M) of the reinforced concrete portion (RC portion) or the concrete portion (C portion) that becomes the internal structure portion of the steel pipe 18 in the internal structure correlation curve creating step S108-4. After calculating the internal structure correlation curve (RC, C), the steel pipe correlation curve (S) created in the previous step S108-3 is accumulated. And the cumulative strength correlation curve (SRC, SC) which shows the axial force (N) -bending moment (M) relationship of the steel pipe winding part (SRC part, SC part) by a cumulative strength formula is created. Specifically, by placing the origin of the steel pipe correlation curve (S) on the internal structure correlation curve (RC, C) and moving the origin along the internal structure correlation curve (RC, C), The outer edge line of the moving region becomes a cumulative intensity correlation curve (SRC, SC).

  When the internal structure portion of the steel pipe 18 is reinforced concrete RC like the steel pipe reinforced concrete pile portion 12 of the present embodiment, the cumulative strength correlation curve (SRC) when all the three protruding rings 28 are installed is shown in FIG. ), The curved portion has a substantially mountain shape that reaches the bottom. Further, the cumulative intensity correlation curve (SRC) when only one protrusion ring 28 is installed has a shape in which the skirt of the substantially mountain shape is in a vertical state as shown in FIG. The width of the axial force (N) becomes narrower. Further, as shown in FIG. 6C, the cumulative strength correlation curve (SRC) when the number of the protrusion rings 28 is zero is smaller than the width of the axial force (N) as shown in FIG. The shape is the same as the width of the axial force (N) of the structural correlation curve (RC).

  On the other hand, when the internal structure portion of the steel pipe 18 is concrete C, the cumulative strength correlation curve (SC) when all three projection rings 28 are installed is as shown in FIG. It has a substantially mountain shape that reaches the bottom. In addition, as shown in FIG. 7B, the cumulative intensity correlation curve (SC) when only one protrusion ring 28 and a part of the protrusion ring 28 are installed is in a vertical state at the bottom of the substantially mountain shape. The width of the axial force (N) becomes narrow. Furthermore, as shown in FIG. 7C, the cumulative intensity correlation curve (SC) when the number of the projecting rings 28 is zero, the axial force (N) is narrower than that in FIG. It has the same shape as the width of the axial force (N) of the structural correlation curve (C).

  Regardless of whether the internal structure of the steel pipe 18 is reinforced concrete RC or concrete C, the case where only one part of the projecting ring 28 is installed is three cases where all of the projecting rings 28 are installed. In comparison, the cumulative intensity correlation curve (SRC, SC) has a shape with a narrow axial force width. From this, when the fixing force required in the design process of the cast-in-place pile 10 is obtained and the size thereof is smaller than that in which all the protruding rings 28 are installed, the cumulative strength correlation curve shown in FIG. The skirt regions on both end sides of (SRC) are for overspec.

  Therefore, in this embodiment, a steel pipe correlation curve is created based on the fixing force of the provisionally determined specifications at the fixing portions 26a and 26b provided at the ends 18a and 18b of the steel pipe 18. Then, using the steel pipe correlation curve, a cumulative strength correlation curve used for determining the validity of the fixing force in the fixing portions 26a and 26b is created. For this reason, the fixing force to be generated can be set to a desired magnitude according to the number of protrusion rings 28 provided to increase the fixing force of the fixing portion 26b provided at the lower end portion 18b of the steel pipe 18. Similarly, the generated fixing force can be set to a desired magnitude according to the number of pile head fixing bars 22 provided to increase the fixing force of the fixing portion 26a provided on the upper end portion 18a of the steel pipe 18. become.

  Therefore, the cumulative strength correlation curve created in the cumulative strength correlation curve creation step S108-5 can be used to design suitable fixing portions 26a and 26b that can secure the fixing force set to a desired size. Become. That is, after calculating the fixing force of a desired size in the fixing force calculation step S108-2, the appropriate fixing force is calculated using the steel pipe correlation curve and the cumulative strength correlation curve created based on the fixing force. In the fixing unit specification determination step S110, which is a subsequent step, after determining the characteristics, the specifications of the fixing units 26a and 26b that can secure a fixing force of a desired size by the fixing method set in the setting step S108-1. Can be determined.

  Next, details of the bending stress examination step S109 included in the design method of the cast-in-place pile 10 according to the embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a flowchart showing the details of the bending stress examination step included in the design method of the cast-in-place pile according to one embodiment of the present invention, and FIG. 9 shows the cast-in-place pile according to the embodiment of the present invention. It is explanatory drawing which shows an example of the bending stress examination process included in the design method.

In the bending stress examination step S109, the validity of the bending stress with respect to the bending strength is examined. Specifically, first, determines the size relationship (bending stress values determined with flexural capacity M _U bending stress M _E and Kuitai 10 occurring pile body 11 at the minimum value N _L-E Seismic axial force Step S109-1). That is, in this process S109-1, as shown in FIG. 9, it is determined whether the bending stress indicating the generated stress A1 is included in the cumulative strength correlation curve indicating the pile body strength A2.

Flexural Flexural Strength M _U is smaller than the bending stress M _E is Kuitai 10 generated in the pile 11 by stress value determination step S109-1, that is, the minimum value N _L-E bending stress indicates stress generated A1 in the pile body If it is determined that it is included in the cumulative strength correlation curve indicating the proof strength A2, then the bending stress M _E generated in the pile body 11 at the maximum value N _{L + E} of the axial force during earthquake and the bending proof strength M _U of the pile body 10 will be described. Is determined (bending stress value determination step S109-2).

Bending stress generated in the pile body 11 by bending stress value determination step S109-2 M _E flexural strength M _U smaller than Kuitai 10, i.e., the maximum value N _{L +} pile body yield strength bending stress indicates stress generated A1 in _E A2 Is determined to be included in the cumulative strength correlation curve indicating the following, then, the verification ratio M _E / which is the ratio of the bending stress M _E to the bending strength M _U at the minimum value N _L-E of the axial force during an earthquake M _U is determined whether the appropriate value (test ratio determining step S109-3).

When test ratio M _E / M _U in the assay ratio determination step S109-3 is determined to be proper value, then test ratio M _E / M _U at the maximum value N _{L + E} Seismic axial force in a proper value It is determined whether or not there is (test ratio determination step S109-4). When the test ratio M _E / M _U in this step S109-4 is determined to be proper value, it can be seen that the fixing force calculated in step S108-2 to secure the fixing force of reliably minimum necessary Therefore, the specifications of the fixing units 26a and 26b that can secure a fixing force of a desired size can be determined in the fixing unit specification determining step S110 (see FIG. 3) as the next step.

That is, by performing the bending stress examination step S109, the upper end portion 18a and the lower end portion 18b of the steel pipe 18 are taken into consideration based on the validity of the bending stress with respect to the bending strength calculated in step S108-2 of the bending strength calculation step 108. Since the specifications of the fixing portions 26a and 26b for securing the fixing force of a desired size in are determined, it is possible to reliably design the fixing portions 26a and 26b that ensure further safety. Incidentally, the test ratio determining step S109-3, the proper value of the test ratio M _E / M _U in S109-4 is the predetermined data designer in the design of the place pile 10 such as ground information and past design data Based on the pre-set.

On the other hand, the test ratio determining step S109-3, in S109-4, when the test ratio M _E / M _U is determined not to be appropriate values, then, whether test ratio M _E / M _U excessive or too small It is determined (over / under determination step S109-5, S109-6).

Specifically, in the assay ratio determination step S109-3, the minimum value N test ratio M _E / M _U from being determined not to be a proper value in _L-E, the minimum value at an excessive under-determining step S109-5 N _L If the test ratio M _E / M _U in _-E is judged excessive, as shown in FIG. 8, and proceeds to the tension side comparison step S109-9 to be described later. On the contrary, when the test ratio M _E / M _U at the minimum value N _L-E in an excessive under-determining step S109-5 is determined to too small, the steel pipe rolled specification selection step S105 to select the specifications of the steel pipe 18 Return to.

On the other hand, the test ratio determined in step S109-4, the maximum value N _{L +} test ratio M _E / M _U from being determined not to be a proper value in _E, test ratio M _E at the maximum value N _{L + E} with excessive under-determining step S109-6 / M _{when U} is determined excessive, as shown in FIG. 8, it shifts to the compression side comparison step S109-7 to be described later. On the contrary, when the test ratio M _E / M _U at the maximum value N _{L + E} with excessive under-determining step S109-6 is determined to too small, the flow returns to the steel pipe winding specification selection step S105 to select the specifications of the steel pipe 18 .

Thus, when the test ratio is calculated based on the fixing force calculated in bending strength calculation step M _E / M _U is not appropriate values, and selecting the specification of the steel pipe 18 again, the steel pipe 18 more reliably By redesigning the fixing portions 26a and 26b that can secure the necessary fixing force in the fixing portions 26a and 26b provided at the upper end portion 18a and the lower end portion 18b, a more suitable design can be achieved.

Further, in the bending stress value determination step S109-1, the bending stress M _E generated in the pile body 11 at the minimum value N _L-E of the axial force at the time of the earthquake is greater than the bending strength M _U , that is, the generated bending stress M _E. There when it is determined not to be included in the cumulative intensity correlation curve, when the bending stress M _E in the minimum value N _L-E is found not included in the cumulative intensity correlation curve, steel The magnitude relationship between the tensile yielding axial force (-tNs) of 18 and the fixing force (-tNb) with respect to the tensile force is compared (tensile side comparison step S109-9).

  When it is determined in the tension side comparison step S109-9 that the tensile yield axial force (-tNs) is smaller than the fixing force (-tNb) with respect to the tensile force, the tensile yield axial force (-tNs) is increased. The process proceeds to the tension side cost comparison step S109-10 for examining the magnitude relationship between the necessary cost C (tNb) and the necessary cost C (Ms) for increasing the bending strength Ms of the steel pipe when the axial force is zero.

On the other hand, the bending stress value determination step S109-2, greater than the maximum value N _{L +} Strength Flexural bending stress M _E generated in the pile 11 in _E M _U Seismic axial force, i.e., generated bending stress M _E is cumulatively If it is determined not to be included in the intensity correlation in curves, when the maximum value N _{L +} bending in _E stress M _E is determined not to be included in the cumulative intensity correlation curve, the compressive yield of the steel pipe 18 The magnitude relationship between the axial force (cNs) and the fixing force (cNb) with respect to the compression force is compared (compression side comparison step S109-7).

  Then, when it is determined in the compression side comparison step S109-7 that the compression yield axial force (cNs) is larger than the fixing force (cNb) with respect to the compression force, the necessary cost C for increasing the compression yield axial force (cNs). The process proceeds to the compression-side cost comparison step S109-8 that examines the magnitude relationship between (cNb) and the necessary cost C (Ms) for increasing the bending strength Ms of the steel pipe when the axial force is zero.

  On the other hand, when it is determined in the compression side comparison step S109-7 that the compression yield axial force (cNs) is smaller than the fixing force (cNb) with respect to the compression force, and in the tension side comparison step S109-9 described above, the tensile yield axial force ( When it is determined that -tNs) is larger than the fixing force (-tNb) with respect to the tensile force, the process returns to the steel pipe winding specification selection step S105 for selecting the specifications of the steel pipe 18. Further, it is determined that the required cost C (Ms) for increasing the bending resistance Ms of the steel pipe when the axial force is 0 in the compression side cost comparison step S109-8 and the tension side cost comparison step S109-10 is smaller. In the case of the failure, the process returns to the steel pipe winding specification selection step S105 for selecting the specifications of the steel pipe 18 in the same manner. Further, when it is determined in the tension side comparison step S109-9 that the tensile yield axial force (-tNs) is larger than the fixing force (-tNb) with respect to the tensile force, the steel pipe winding specification selection for selecting the specifications of the steel pipe 18 is also performed. The process returns to step S105.

  On the other hand, in the compression side cost comparison step S109-8 and the tension side cost comparison step S109-10, it is determined that the necessary cost C (Ms) for increasing the bending strength Ms of the steel pipe when the axial force is 0 is larger. If it is, the bending strength calculation step S108 for calculating the bending strength of the pile body 11 is returned to. Note that methods for increasing the bending strength Ms of the steel pipe when the axial force is 0 include improvement of the steel pipe material, increase of the steel pipe plate thickness, and pile diameter.

  As described above, in the present embodiment, the stress generated in the pile body on the compression side and the tension side is compared with the cumulative strength indicating the yield strength of the pile body, and the stress generated in the pile body indicates the cumulative strength indicating the yield strength of the pile body. When it is larger than the strength, the cause of the defect can be efficiently examined. In addition, after considering the necessary cost for solving the problem of the calculated fixing force on the compression side and the tension side, it is possible to redo the design from a more suitable process.

  Thus, in this embodiment, in the bending stress examination step S109, the validity of the bending stress with respect to the bending strength calculated in step S108-2 of the bending strength calculation step 108 can be examined. For this reason, when determining the specifications of the fixing unit 26, the fixing force in the fixing units 26a and 26b provided on the upper end 18a and the lower end 18b of the steel pipe 18 is more reliably ensured, so that safety is further ensured. The fixing portions 26a and 26b can be reliably designed. In addition, when the bending stress is not appropriate, according to the cause of the failure, the allocation is performed so that it can be started again from a suitable process, so that the working efficiency can be improved when the cast-in-place pile 10 is redesigned. .

  In the above-mentioned method for designing a cast-in-place pile according to one embodiment of the present invention, the user performs all the steps S101 to S115 shown in FIG. 3, but the bending strength calculation step S108 and the bending stress examination step S109. It is also possible to determine the validity of the specifications of the fixing units 26a and 26b by performing only the above.

  For example, as shown in FIG. 10, after obtaining various data set in steps S101 to S107 performed by other users (step S201), based on these various data, the bending strength calculation step S108 and the bending stress are obtained. The examination step S109 can be performed.

  Thereafter, based on the cumulative strength correlation curve obtained in the bending strength calculation step S108, the bending stress value determination step S109-1, S109-2, the verification ratio determination step S109-3, S109- in the bending stress examination step S109 described above. 4. Over / under determination step S109-5, S109-6, compression side comparison step S109-7, and tension side comparison step S109-9 are appropriately performed.

  When it is determined that the bending stress is appropriately included in the cumulative strength correlation curve in each of the bending stress value determination steps S109-1 and S109-2 and the test ratio determination steps S109-3 and S109-4, the fixing unit 26a. , 26b is appropriate (step S202), and the study is temporarily terminated.

Also, test ratio M _E / M _U at the minimum value N _L-E in the assay ratio determination step S109-3 is determined not to be a proper value, and test at the minimum value N _L-E in an excessive under-determining step S109-5 even when the ratio M _E / M _U is determined to too small, the fixing portion 26a, 26b specifications as a valid (step S202), temporarily finishes the study.

Furthermore, test ratio determining test ratio at the maximum value N _{L + E} in step S109-4 M _E / M _U is determined not to be a proper value, and test ratio in the maximum value N _{L + E} with excessive under-determining step S109-6 M _E / sometimes M _U is determined to too small, the fixing portion 26a, 26b specifications as a valid (step S202), temporarily finishes the study.

  As described above, when the specifications of the fixing units 26a and 26b are appropriate (step S202) and the examination is once completed, the detailed examination of the fixing units 26a and 26b may be subsequently started. Is possible.

On the other hand, if the test ratio M _E / M _U with excessive under-determination step S109-5 in the minimum value N _L-E is determined excessive, the process moves to the tension side comparison step S109-9, tensile steel pipe 18 The magnitude relationship between the yielding axial force (−tNs) and the fixing force against the tensile force (−tNb) is compared. Also, if the test ratio in the maximum value N _{L + E} with excessive under-determining step S109-6 M _E / M _U is determined excessive, and proceeds to the compression side comparison step S109-7, the compressive yield axis of the steel pipe 18 The magnitude relationship between the force (cNs) and the fixing force (cNb) with respect to the compression force is compared.

  In the compression side comparison step S109-7 and the tension side comparison step S109-9, when it is determined that the compression yield axial force (cNs) is larger than the fixing force (cNb) with respect to the compression force, or when the tensile yield axial force (− When it is determined that (tNs) is smaller than the fixing force (−tNb) with respect to the tensile force, the process returns to the bending strength calculation step S108 and starts again from the calculation of the bending strength.

  On the other hand, when it is determined in the compression side comparison step S109-7 or the tension side comparison step S109-9 that the compression yield axial force (cNs) is smaller than the fixing force (cNb) with respect to the compression force, the tensile yield axial force (− When it is determined that (tNs) is larger than the fixing force (−tNb) with respect to the tensile force, the specifications of the fixing units 26a and 26b are inappropriate (step S203), and the examination work is finished.

  In this way, the bending strength calculation step S108 and the bending stress examination step S109 are performed based on the various data set by the steps S101 to S107 performed by other users, and the bending strength calculation step S108 and the bending stress examination are performed. It is also possible to perform only step S109 and determine the validity of the specifications of the fixing units 26a and 26b.

  Although each embodiment of the present invention has been described in detail as described above, it is easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. It will be possible. Therefore, all such modifications are included in the scope of the present invention.

  For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Also, the configuration of the cast-in-place pile design system and the operation of the cast-in-place pile design method are not limited to those described in the embodiments of the present invention, and various modifications can be made.

DESCRIPTION OF SYMBOLS 10 Pile head steel pipe winding cast-in-place concrete pile (cast-in-place pile), 11 pile body, 11a pile head, 12 steel pipe reinforced concrete pile part, 14 reinforced concrete pile part, 16 main reinforcement, 18 steel pipe, 18a upper end, 18b lower end, 20 inside Reinforced concrete (internal structure part), 22 pile head anchoring muscle, 24 pile cap, 26, 26a, 26b anchoring part, 28 projection ring, 100 (place cast pile) design system, 101 computer, 102 storage part, 104 storage medium, 106 RAM, 108 ROM, 110 CPU (calculation unit), 112 setting unit, 113 correlation curve creation unit (steel pipe correlation curve creation unit, internal structure correlation curve creation unit, cumulative strength correlation curve creation unit), 114 determination unit ( Fixing force determination unit), 116 determination unit (fixing unit specification determination unit), 120 input unit, 12 2 output section, 124 communication section, 125 system bus, 126 internet, S105 steel pipe winding specification selection process, S107 bending stress calculation process, S108 bending strength calculation process, S108-1 setting process, S108-2 fixing force calculation process, S108- 3 Steel pipe correlation curve creation step, S108-4 Internal structure correlation curve creation step, S108-5 Cumulative strength correlation curve creation step, S109 Bending stress examination step, S109-1, S109-2 Bending stress value judgment step, S109- 3, S109-4 test ratio determination step, S109-5, S109-6 over / under determination step, S109-7 compression side comparison step, S109-8 compression side cost comparison step, S109-9 tension side comparison step, S109-10 Tensile side cost comparison process

The present invention is a method of designing a place pile, design program, storage medium, location Pile design system, and bending strength calculation method relating to the place pile.

One aspect of the present invention is a design method of a cast-in-place pile in which a steel pipe is wound around a pile head of the pile body including at least a bending strength calculation step of calculating a bending strength of the pile body, the bending strength The calculation step includes a setting step for setting a fixing method between the steel pipe at least at the upper end portion and the lower end portion of the steel pipe and an internal structure portion made of either internal concrete or internal reinforced concrete provided in the steel pipe, and the steel pipe The minimum value calculated as the smaller value of the fixing force with the internal structure portion with respect to the compression side at the upper end portion and the lower end portion, and the internal structure with respect to the tension side at the upper end portion and the lower end portion of the steel pipe and a minimum value calculated as smaller of the fixing force of the portion is calculated as the fixing force of each of the steel pipe in the compression side and the tension side fixing A calculation step, comparing said fixing force the compression side calculated in the calculation step and the fixing force of the tension side, a magnitude relation between the tensile yield axial force of the compression yield axial forces and the steel pipe of the steel pipe, large-small based on the relationship, the pipe for the correlation curve creation step of creating a steel pipe for correlation curve showing the relationship between the axial force and bending moment of the steel tube portion of the pile body, the internal concrete or the internal reinforced concrete of the inner structural portion The internal structure correlation curve creating step for creating the internal structure correlation curve indicating the relationship between the axial force and the bending moment, and the steel structure correlation curve is added to the internal structure correlation curve to increase the bending strength. includes a cumulative intensity correlation curve creation step of creating a cumulative intensity correlation curve showing, and the process after the bending strength calculation step, before the preset predetermined minimum value of the axial force and the maximum value And wherein the bending stress generated in the pile body comprises a fixing portion specification determination step of determining the specifications of the fixing portion between the steel pipe to be smaller than the bending strength and the inner structural portion represented by the cumulative intensity correlation curve To do.

Another aspect of the present invention is a cast-in-place pile design system in which a steel pipe is wound around a pile head of a pile body, and stores at least predetermined data relating to the design of the cast-in-place pile Minimum value of fixing force with the internal structure portion made of either internal concrete or internal reinforced concrete on the compression side at least at the upper end portion and the lower end portion of the steel pipe, and minimum fixing force with the internal structure portion on the tension side A calculation unit that calculates a fixing force at the upper end portion and the lower end portion of the desired steel pipe based on the value; and included in the calculation unit, at least the steel pipe at the upper end portion and the lower end portion of the steel pipe, and the steel pipe A setting unit that sets a fixing method with an internal structure portion provided inside, and the steel included in the pile body, which is included in the calculation unit, based on the fixing force on the compression side and the tension side A correlation curve creating section for creating a steel pipe correlation curve showing the relationship between the axial force of the part and the bending moment, and the calculation part included in the correlation section for the steel pipe, and the relation between the axial force and the bending moment of the internal structure part of the steel pipe A cumulative strength correlation curve creating unit that creates the cumulative strength correlation curve by accumulating the steel pipe correlation curve to the internal structure correlation curve shown in FIG. 4 and is set in advance using at least the cumulative strength correlation curve. a fixing force judging unit that the bending stress generated in the pile body at the predetermined minimum value and maximum value of the axial force is determined whether or not included in the cumulative intensity correlation in curves, is included in the calculation unit, when the bending stress in a given said minimum value and said maximum value of said axial force is included in the cumulative intensity correlation in curves, ensuring at least the fixing force by the fixing method set by the setting unit Characterized in that it comprises a fixing portion specification determination section for determining the specifications of the fixing portion of the capacity of the steel pipe and the internal structure portion.

Another aspect of the present invention is a method for calculating the bending strength of a cast-in-place pile in which the steel pipe is wound around the pile head of the pile body. And a setting step for setting a fixing method between the steel pipe at the lower end portion and an internal structural portion made of either internal concrete or internal reinforced concrete provided inside the steel pipe, and compression at the upper end portion and the lower end portion of the steel pipe The minimum value calculated as the smaller value of the fixing force with the internal structure portion with respect to the side, and the value with the smaller fixing force with the internal structure portion with respect to the tension side at the upper end portion and the lower end portion of the steel pipe A minimum value calculated as a fixing force calculation step for calculating the fixing force of the steel pipe on the compression side and the tension side, and a fixing force calculation step. Compare the magnitude relationship between the fixing force on the compression side and the tension side and the compression yield axial force of the steel pipe and the tensile yield axial force of the steel pipe, and based on the magnitude relationship, the steel pipe portion of the pile body A correlation curve creating step for creating a steel pipe correlation curve showing the relationship between the axial force and bending moment of the steel pipe, and the relationship between the axial force and bending moment of either the internal concrete or the internal reinforced concrete of the internal structure portion An internal structure correlation curve creating step for creating an internal structure correlation curve, and a cumulative strength correlation curve for creating a cumulative strength correlation curve indicating the bending strength by accumulating the steel pipe correlation curve to the internal structure correlation curve And a creation step.

According to another aspect of the present invention, after calculating the fixing force between the steel pipe and the internal structure portion at the end of the steel pipe in the fixing force calculating step, a plurality of correlation curves for the steel pipe are created based on the fixing force. Thus, the yield strength of the steel pipe winding portion can be changed, so that a more preferable bending strength of the steel pipe winding portion can be calculated.

Claims (10)

A method for designing a cast-in-place pile including a bending strength calculation step for calculating at least a bending strength of a pile body, wherein a steel pipe is wound around a pile head of the pile body,
The bending strength calculation step includes
A setting step of setting a fixing method between the steel pipe at least at the upper end portion and the lower end portion of the steel pipe and an internal structure portion made of either internal concrete or internal reinforced concrete provided in the steel pipe;
Based on the minimum value of the fixing force with the internal structure portion with respect to the compression side at the upper end portion and the lower end portion of the steel pipe, and the minimum value of the fixing force with the internal structure portion with respect to the tension side, the desired steel pipe A fixing force calculation step of calculating a fixing force at the upper end and the lower end;
Based on the fixing force calculated in the fixing force calculation step, the steel pipe correlation curve indicating the relationship between the axial force and bending moment of the steel pipe portion of the pile body is created. Correlation curve creation process;
A correlation curve creating step for internal structure that creates a correlation curve for internal structure showing a relationship between an axial force and a bending moment of the internal structure portion of the steel pipe;
A cumulative strength correlation curve creating step of creating a cumulative strength correlation curve by accumulating the steel pipe correlation curve in the internal structure correlation curve,
In the subsequent step of the bending strength calculation step, using the cumulative strength correlation curve, the specification of the fixing portion of the steel pipe and the internal structure portion that can secure the fixing force by the fixing method set in the setting step A method for designing cast-in-place piles, comprising a fixing part specification determining step for determining the position. Bending stress calculation step for calculating bending stress generated in the pile body;
A bending stress examination step for examining the validity of the bending stress with respect to the bending strength after the bending strength calculation step,
The bending stress examination step
The cast-in-place value according to claim 1, further comprising a bending stress value determining step of determining whether or not the bending stress at the minimum value and the maximum value of the axial force during an earthquake is included in the cumulative strength correlation curve. Pile design method. The bending stress examination step
When the bending stress is included in the cumulative strength correlation curve in the bending stress value determining step, a test ratio that is a ratio between the bending stress and the bending strength at the minimum value and the maximum value is an appropriate value. A test ratio determination step of determining whether or not there is a
An over / under determination step in which, in the test ratio determination step, when it is determined that the test ratio at the maximum value or the minimum value is not an appropriate value, the test ratio is determined to be over or under. ,
Returning to the steel pipe winding specification selection step for selecting the specifications of the steel pipe having the preceding stage from the bending stress calculation step and the bending strength calculation step when the verification ratio is determined to be excessive in the over / under determination step. The cast-in-place pile design method according to claim 2, In the bending stress value determining step, when it is determined that the bending stress at the maximum value or the minimum value is not included in the cumulative strength correlation curve,
When it is determined that the bending stress at the minimum value is not included in the cumulative strength correlation curve, a tensile strength comparing the magnitude relationship between the tensile yield axial force of the steel pipe and the fixing force with respect to the tensile force is compared. To the side comparison process,
When it is determined that the bending stress at the maximum value is not included in the cumulative strength correlation curve, compression is performed to compare the magnitude relationship between the compression yield axial force of the steel pipe and the fixing force with respect to the compression force. 3. The cast-in-place pile design method according to claim 2, wherein the method is shifted to a side comparison step.   When it is determined in the tension side comparison step that the tensile yield axial force of the steel pipe is smaller than the fixing force with respect to the tensile force, the cost required to increase the tensile yield axial force and the axial force are 0 5. The cast-in-place pile design method according to claim 4, wherein the cast-in-place pile is transferred to a tension-side cost comparison step for examining a magnitude relationship with a necessary cost for increasing the bending strength of the steel pipe.   When it is determined in the compression side comparison step that the compression yield axial force of the steel pipe is larger than the fixing force with respect to the compression force, the cost required to increase the compression yield axial force and the axial force are 0 5. The cast-in-place pile design method according to claim 4, wherein the cast-in-place pile design method shifts to a compression-side cost comparison step for examining a magnitude relationship with a necessary cost for increasing the bending strength of the steel pipe.   A design program for causing a computer to execute the cast-in-place pile design method according to any one of claims 1 to 6.   A storage medium that stores a computer-readable design program for causing a computer to execute the cast-in-place pile design method according to any one of claims 1 to 6. A cast-in-place pile design system in which a steel pipe is wound around a pile head of a pile body,
A storage unit for storing at least predetermined data relating to the design of the cast-in-place pile;
At least at the upper end and lower end of the steel pipe, the minimum value of the fixing force with the internal structure part made of either internal concrete or internal reinforced concrete on the compression side, and the minimum value of the fixing force with the internal structure part on the tension side Based on the calculation unit for calculating the fixing force at the upper end and the lower end of the desired steel pipe,
A setting unit that is included in the calculation unit and sets a fixing method of the steel pipe at least at the upper end portion and the lower end portion of the steel pipe and an internal structure portion provided inside the steel pipe;
Correlation for steel pipe that is included in the calculation unit and creates a correlation curve for steel pipe showing the relationship between the axial force and bending moment of the steel pipe portion of the pile body based on the fixing force on the compression side and the tension side A curve generator,
A cumulative strength correlation curve, which is included in the calculation unit, creates a cumulative strength correlation curve by accumulating the correlation curve for an internal structure to a correlation curve for an internal structure indicating a relationship between an axial force and a bending moment of the internal structure portion of the steel pipe The creation department;
A fixing force determination unit that is included in the calculation unit and examines the adequacy of the fixing force using at least the cumulative intensity correlation curve;
A cast-in-place pile design comprising: a fixing unit specification determining unit which is included in the calculation unit and determines a specification of a fixing unit between the steel pipe and the internal structure portion which can secure at least the fixing force. system.   The storage unit, as the predetermined data, a database of at least soil soil data where the cast-in-place pile is provided, specification data relating to components of the pile body, and past design performance data of the cast-in-place pile The cast-in-place pile design system according to claim 9, wherein the cast-in-place pile is stored.

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