JP2015030985A - Design method of composite structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a design method of a composite structure, easily executable, besides being capable of properly evaluating the burying length of a steel material of a composite structure beam of a burying form.SOLUTION: The present invention is a design method of a composite structure beam having the steel material for forming a central part and burying a part in a material end part and concrete filled in the material end part, and formed in a long size shape out of the central part of a steel frame structure and the material end part of a reinforced concrete structure. The central part is formed as an elastic rigidity S beam N11 based on the steel material, and the material end part is formed as an elastic rigidity RC beam M12 based on reinforced concrete of burying the steel material, and structural design is executed by setting an evaluation model M1 of joining the S beam and the RC beam by an elastic rigidity bending spring M13 based on rigid body rotation of the steel material.

Description

  The present invention relates to a method for designing a composite structure formed in a long shape like a beam or a column by a central part of a steel structure and a material end part of a reinforced concrete structure.

  In order to reduce the beam weight for the purpose of extending the span of the beam, a composite structure beam is known in which the center part has a light steel structure with its own weight and only the end part of the material joined to a column or wall has a reinforced concrete structure (patented) Reference 1-3).

  The composite structural beams disclosed in these documents are in the embedded form in which the end of the steel frame is embedded in the end of the reinforced concrete structure. In Non-Patent Document 1, the embedded structural dynamics is modeled and explained.

  Moreover, in patent document 1, while arranging an end plate in the end surface of a material end part, while fixing the main reinforcement of a material end part to the end plate, the mixed structure beam which integrated the end plate and the steel frame dynamically Is disclosed.

  On the other hand, Patent Document 2 discloses a composite structural beam in which the main reinforcement at the end of the material and the steel frame are mechanically integrated without being connected. In this composite structural beam, the main bar is fixed by attaching a disk-shaped fixing plate to the end of the main bar at the end of the material.

  Further, in FIGS. 5 and 6 of Patent Document 3, a rectangular fixing plate is arranged at the top and bottom of the end of the material sandwiching the steel frame, and the tip of the main bar is fixed to the fixing plate with a nut. Is disclosed.

JP 2011-231509 A JP 2005-76379 A JP-A-1-268947

The Architectural Institute of Japan, “Stress transmission and resistance mechanism of steel-concrete structural joints”, The Architectural Institute of Japan, February 25, 2011

  However, a design method that can evaluate the member rigidity of the embedded composite beam disclosed in Patent Documents 1-3 in consideration of the length of the steel frame embedded in the material end has not been established.

  Further, in Patent Document 3, the result of the experiment for confirming the behavior of the composite structural beam is shown in FIG. 12 as the relationship between force and deformation. Since the elastic stiffness derived from the angular relationship is used as an input value, it cannot be applied to design practice as it is.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a composite structure design method that can be easily evaluated in addition to the appropriate evaluation of the embedded length of the steel material of the embedded composite structural beam.

  In order to achieve the above object, a method for designing a composite structure of the present invention includes a steel material that forms a central portion and is partially embedded in a material end portion, and is disposed substantially parallel to the steel material at the material end portion. A central portion of the steel structure, comprising: a main reinforcing bar, a plurality of shear reinforcing bars arranged at intervals in the axial direction so as to surround the steel material and the main reinforcing bar, and concrete filled in the end of the steel member; A method for designing a composite structure formed in a long shape by a material end portion of a reinforced concrete structure, wherein the central portion is an elastic rigid rod-shaped steel model based on the steel material, and the material end portion is An elastic-rigid rod-shaped reinforced concrete model based on reinforced concrete with embedded steel is used, and the steel frame model and the reinforced concrete model are connected by an elastic-rigid bending spring based on the rigid body rotation of the steel. Set the evaluation model is characterized by performing structural design using the evaluation model.

  Further, a composite structure in which a boundary plate is disposed at a boundary between the central portion and the material end portion, and a tip of the main bar is fixed to the boundary plate may be used. Further, the expression representing the elastic rigidity of the reinforced concrete model can include the length of the steel material embedded in the material end.

  Then, when there is a change in the detailed specifications of the composite structure, the evaluation model is changed by changing the reference model corresponding to the change to the reinforced concrete model obtained by developing based on the beam theory and the elastic rigidity of the bending spring. Can be set. Depending on the detailed specifications, only the elastic rigidity of the bending spring can be changed to set the evaluation model. For example, when the boundary plate and the steel material are joined by welding, a continuous condition can be set at the position of the boundary plate to determine the elastic rigidity of the bending spring.

  On the other hand, when there is no boundary plate or when the boundary plate and the steel material are not dynamically integrated, a continuous condition is set at the end position of the steel material to obtain the elastic rigidity of the bending spring. be able to.

  In addition, nonlinear behavior can be set in at least one of the reinforced concrete model, the bending spring, or the steel frame model. For example, the nonlinear behavior of the bending spring can be set to a trilinear type equivalent to the nonlinear behavior of the reinforced concrete model. Furthermore, it can be determined from the relationship between force and deformation whether the plastic hinge at the time of non-linear behavior is generated at the end of the end of the material or the embedding start of the steel.

  In the composite structure designing method of the present invention configured as described above, the embedded length of the steel material of the embedded composite structural beam can be appropriately evaluated. Further, by obtaining an elastic stiffness and a restoring force characteristic using an evaluation model in which a steel model and a reinforced concrete model are coupled by a bending spring, various subsequent designs can be easily executed.

It is explanatory drawing explaining the evaluation model of the composite structure beam of embodiment of this invention. It is a flowchart explaining the flow of design of a composite structure beam. It is explanatory drawing which showed the structure of the composite structure beam. It is a perspective view explaining the structure of the beam pillar structure in which the composite structural beam was spanned between the pillars. It is a figure explaining the structure of a composite structure beam, Comprising: (a) is sectional drawing seen in the AA arrow direction of FIG. 3, (b) is sectional drawing seen in the BB arrow direction of FIG. It is. It is explanatory drawing which showed the structure of the reference | standard model referred in order to guide | lead an evaluation model, a bending moment figure, and a shear force figure. (A) It is explanatory drawing which showed the deflection | deviation of the whole composite structure beam, and the deflection | deviation of each structure of a reference | standard model. (B) It is explanatory drawing explaining the structural component of the bending of a reference | standard model. It is explanatory drawing which showed the bending of the reinforced concrete part of the reference | standard model, and the burden bending moment. It is explanatory drawing explaining a continuous condition. It is a figure explaining the nonlinear behavior of an evaluation model, Comprising: (a) is explanatory drawing shown by the relationship between force and a deformation | transformation, (b) is explanatory drawing shown by the relationship between a bending moment and a member deformation angle. It is a figure explaining the structure of the composite structure beam of Example 1, Comprising: (a) is sectional drawing (refer AA arrow direction of FIG. 3), (b) is sectional drawing (BB arrow of FIG. 3). Viewing direction). FIG. 5 is an explanatory diagram for explaining continuous conditions of Example 1. It is a figure which verifies an evaluation model in contrast with an experimental result, Comprising: (a) is the graph which showed the verification result of the evaluation model of this Embodiment, (b) shows the verification result of the evaluation model of Example 1. It is a graph. It is a figure explaining the difference by the formation position of the plastic hinge of an evaluation model, (a) is a graph which showed the verification result of RC hinge form, (b) is a graph which showed the verification result of S hinge type. It is explanatory drawing which showed the structure of the composite model beam of Example 4, and the structure of the reference | standard model referred in order to guide | lead the evaluation model.

  Hereinafter, a method for designing a composite structure according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining an evaluation model M1 used in the composite structure design method of the present embodiment. Moreover, FIG. 2 is a figure explaining the flow of a general structural design.

  In the structural design, the primary design is studied within the range of elastic stiffness for small and medium-sized earthquakes, and the restoring force characteristics (nonlinear behavior) are taken into consideration for large earthquakes so that they do not collapse without significant damage. There is a secondary design called.

  Here, when designing a composite structure to be described later, if “elastic stiffness” and “restoring force characteristics” are accurately shown, the primary design and secondary design should be appropriately performed using them. Can do. Therefore, an evaluation model M1 for deriving “elastic stiffness” and “restoring force characteristics” used in the method for designing a composite structure of the present embodiment will be described below.

  First, the configuration of the composite structural beam 1 as a composite structure to be designed and the beam pillar structure 2 as a building on which the composite structural beam 1 is provided will be described with reference to FIGS.

  FIG. 4 is a perspective view showing the overall configuration of the beam post structure 2. The beam pillar structure 2 has a structure in which the composite structural beam 1 is bridged between the upper parts of two pillars 21 and 21 constructed with a space between reinforced concrete structures.

  The composite structural beam 1 is formed in an elongated shape by a material end portion 12 to be joined to the upper side surface of the column 21 and a central portion 11 between the material end portions 12 and 12. Moreover, the material edge part 12 is a reinforced concrete structure, and the center part 11 has a steel frame structure. In other words, the material end 12 is from the tip 121 to the end 122 that is a reinforced concrete structure, and the center 11 is between the tips 121 and 121 of the material end 12 that is a steel structure.

  The steel frame 3 forming the central portion 11 is a steel material in which a pair of parallel flanges 31 and 32 are connected by a web 33. For example, H-shaped steel materials, I-shaped steel materials, groove-shaped steel materials, and the like can be used. Below, the case where the steel frame 3 formed with an H-shaped steel material is applied is demonstrated.

  The central portion 11 corresponds to the exposed portion 3a of the steel frame 3 as shown in FIG. Moreover, the edge part of the steel frame 3 is embedded in the material edge part 12 as the burying part 3b. Therefore, it can be said that part of the material end portion 12 can have a steel-frame reinforced concrete structure because the embedded portion 3b of the steel frame 3 is embedded.

  The boundary plate 4 is disposed at the boundary between the central portion 11 and the material end portion 12, in other words, at the tip 121 of the material end portion 12.

  The boundary plate 4 is disposed so as to surround the outer periphery of the steel frame 3 as shown in FIG. 5A, which is a cross-sectional view taken in the direction of arrows AA in FIG. For example, the boundary plate 4 is formed by punching a hole in accordance with the outer shape of the steel frame 3 in the center of a rectangular steel plate that is substantially the same as the end face shape of the material end portion 12.

  Further, the boundary plate 4 and the steel frame 3 penetrated through the boundary plate 4 are joined by welding 41. As shown in FIG. 5A, the welding 41 is performed along the entire circumference of the steel frame 3. The welding 41 may be performed only partially if the desired strength is reached.

  Further, when the exposed portion 3a and the embedded portion 3b of the steel frame 3 are formed of different steel materials, the above-described steel plate 3 that is not cut out of the steel frame 3 and has the same rectangular shape as the end surface shape of the material end portion 12 is used as the boundary plate 4. Then, the exposed portion 3a and the embedded portion 3b may be brought into contact with each other from both sides and welded together.

  Then, the end 3c of the steel frame 3 embedded in the material end 12 is located slightly closer to the center 11 than the joint surface (the end 122 of the material end 12) with the column 21 as shown in FIG. Further, main bars 5A, 5B, 5C, 5D, 5E, and 5F are arranged on the material end portion 12 substantially parallel to the steel frame 3.

  The main bars 5A-5F are fixed inside the column 21. FIG. 3 illustrates a form in which the fixing plate is attached to the end (end) in the column 21 of the main bar 5A-5F. However, the present invention is not limited to this, and the end is processed into a hook shape. It may be.

  The column 21 to be joined to the material end portion 12 includes a plurality of main reinforcing bars 21a erected in the vertical direction, and a plurality of shear reinforcement bars 21b surrounding the outer periphery and spaced apart in the vertical direction. .. and is formed into a quadrangular prism shape by the concrete 21c.

  And the part which protrudes to the pillar 21 side of the main reinforcement 5A-5F is arrange | positioned so that it may not interfere with the main reinforcement 21a, ... of the pillar 21, and the shear reinforcement 21b, ..., and is integrated by the concrete 21c.

  On the other hand, the tip 52 that is the end of the main muscle 5A-5F on the central portion 11 side is fixed to the boundary plate 4 via a nut 51, as shown in FIG. Further, as shown in FIG. 3, a nut 51a is also mounted on the material end 12 side with the boundary plate 4 interposed therebetween. That is, the front end 52 of the main bars 5A-5F is fixed to the boundary plate 4 by sandwiching the boundary plate 4 with the two nuts 51, 51a.

  3 and 5, the main bars 5A are arranged above the upper flange 31 of the steel frame 3, and the main bars 5C and 5C are arranged on both sides of the flange 31. To do. Also, the main bars 5B are arranged below the flange 32 on the lower side of the steel frame 3, and the main bars 5D and 5D are arranged on both sides of the flange 32. Further, the main bars 5E and 5E are arranged below the flange 31, in other words, on both sides of the upper portion of the web 33. The main bars 5F, 5F are arranged on the upper side inside the flange 32, in other words, on both sides of the lower side of the web 33.

  These main bars 5A-5F are both inside and outside of the steel frame 3 inside the material end portion 12 as shown in FIG. 5 (b) which is a cross-sectional view seen in the direction of arrows BB in FIG. Placed in.

  And the shear reinforcement bars 6 and 6 are arrange | positioned so that the steel frame 3 and the main bars 5A-5F may be enclosed. In FIG. 5B, the shear reinforcement bars 6 and 6 are arranged so as to be shifted left and right so that the steel frame 3 wraps, but the present invention is not limited to this.

  As shown in FIG. 3, a plurality of such shear reinforcement bars 6 are arranged at a constant interval in the axial direction of the composite structural beam 1 (material end portion 12). The interval between the shear reinforcing bars 6 is calculated based on the shearing force acting on the material end 12.

  A concentrated reinforcing bar 7 is disposed in the vicinity of the terminal end 3 c of the steel frame 3. The concentrated reinforcing bar 7 can be formed by narrowing the interval between the shear reinforcing bars 6 installed at other locations. Moreover, it can also be set as the concentrated reinforcement bar 7 using the reinforcing bar formed in the spiral shape.

  Next, the evaluation model M1 used for the design method of the composite structure beam 1 of this Embodiment is demonstrated.

  First, the reference model M0 for deriving the evaluation model M1 will be described with reference to FIG. The reference model M0 is created based on the composite structural beam 1 described above.

  The reference model M0 includes an RC member M8 in which the reinforced concrete portion of the material end 12 is modeled in a beam shape (bar shape), and an S member M3 in which the steel frame 3 is modeled in a beam shape (bar shape).

  The S member M3 pin-supports the embedding start end M31 and the end M32 in the material end portion 12 on the RC member M8. Here, the embedding start end M31 is provided at the tip M121 of the material end portion 12.

  In addition, a terminal end M122 that becomes a joint surface of the material end portion 12 with the column 21 is a fixed end. Further, a downward concentrated load Q is applied to the free end M33 of the S member M3. That is, the cantilever-shaped reference model M0 is created by cutting the central portion 11 of the beam post structure 2 shown in FIG. 4 at the center in the axial direction.

In the middle part of FIG. 6, a burden bending moment M (x) generated in the reference model M0 by the concentrated load Q is shown as a distribution diagram. Here, the axial direction of the composite structural beam 1 is the x direction, the position of the tip M121 of the material end 12 (embedding start end M31 of the S member M3) is x = 0, and the fixed end (the end M122 of the material end 12) side. Is the positive direction and the free end M33 side is the negative direction. The length of the Zaitan portion 12 (tip M121 and end M122 and distance) and _rc l, the length of the embedded portion 3b of Steel 3 (the distance between the buried start M31 and terminal M32) a _s l _b, steel 3 the length of the exposed portion 3a (the distance embedded start M31 and free end M33) was _s l _n of.

The total burden bending moment M (x) is the sum of the burden bending moment _s M (x) borne by the S member M3 and the burden bending moment _rc M (x) borne by the RC member M8. On the other hand, the lower part of FIG. 6, middle burden bending moment _{M (x), s M (} x), rc borne shearing force derived from the slope of M (x) Q (x) , s Q (x), The distribution map of _rc Q (x) is shown.

Using this reference model M0, the deflection curve δ (x) of the entire composite structural beam 1 when the concentrated load Q acts on the free end M33 and the deflection δ = δ ( _−s l _n ) at the free end M33 are derived. Consider how to do it.

In the following, the deflection curve of the composite beam 1 [delta] (x), as shown in FIG. 7 (a), the deflection curve of the RC member M8 _rc [delta] and (x), the deflection curve of the S member M3 _s δ (x) The following formula 1 is assumed to be written.

Also, the derivatives obtained by differentiating these deflection curves δ (x), _rc δ (x), _s δ (x) are converted into the respective deflection angles θ (x), _rc θ (x), _s θ ( x). Further, the deformation amount _s δ (= δ ( _−s l _n ) −δ (0)) of the S member M3 constituting the deflection δ at the free end (M33) of the embedded composite structural beam 1 is shown in FIG. ), It can be decomposed into “deformation _s δ _r due to rotation of RC member M8” and “deflection _s δ _e due to elastic deformation of S member M3”.

Here, it is geometrically obvious that _s δ _r is expressed as the following equation 2 using the deflection angle _s θ (0) of the S member M3 at x = 0 that becomes the tip M121 of the RC member M8. _S δ _e can be expressed by Equation 3 according to the beam theory.

Here, _s E represents the Young's modulus of the S member M3, and _s I represents the cross-sectional second moment of the S member M3.

On the other hand, FIG. 8 shows the force acting on the RC member M8 at this time, the bending curve _rc δ (x) associated therewith, and the bending moment distribution diagram thereof in detail.

  Considering the reference model M0, the concentrated load Q acting on the S member M3 at the free end M33 is transmitted to the RC member M8 via the pins arranged at the positions of the embedded start end M31 and the end M32 of the S member M3. The

For this reason, the deflection curve _rc δ (x) of the RC member M8 needs to be obtained with respect to this stress condition, and the following expression 4 is obtained by solving this based on the beam theory.

Here, _c E represents the Young's modulus of concrete, _rc I _e represents the equivalent moment of inertia of the RC member M8, and _rc I _e does not consider the loss of the cross-sectional area due to the embedded portion 3b of the steel frame 3 However, the effect of reinforcing bars is taken into account.

Further, the deflection angle _rc θ (x) which is a derivative thereof is expressed as the following Expression 5.

Here, Expression 4 corresponds to the first expression of Expression 1. Further, from this equation 4, the relationship between the concentrated load Q acting on the free end M33 and the deflection _rc δ = _rc δ (0) at the tip M121 of the RC member M8 can be expressed as the following equation 6.

Subsequently, the deflection curve _s δ (x) of the S member M3 joined to the RC member M8 via a pin is obtained using the continuous condition with the deformation of the RC member M8 developed so far. In the composite structural beam 1 according to the present embodiment, the steel frame 3 and the boundary plate 4 are joined by welding 41 as shown in FIG.

  For this reason, as shown in FIG. 9, it is considered that the RC member M8 and the S member M3 behave integrally at the position (x = 0) of the embedded start end M31 where the RC member M8 and the S member M3 are integrated by welding, and even at the position of the tip M121 of the RC member M8. Assume that at a pin located at x = 0, both deflection curves are continuous, including the deflection angle.

That is, in this case, the deflection curve _s δ (x) of the S member M3 and the deflection angle _s θ (x) which is a derivative thereof are expressed as _s δ (0) = _rc δ (0) and _s θ (0) = _rc It can be obtained by beam theory with θ (0) as an initial condition, and can be expressed as the following equations 7 and 8.

The second expression of Expression 7 corresponds to the second expression of Expression 1. That, x = to the formula - _s l _n deflection obtained by substituting _{s δ} (- _s l _n) is the deflection at the free end of the composite structural beam 1 (M33) δ = δ ( - s l n) It becomes. Then, a value obtained by subtracting _rc δ = _rc δ (0) from this value is _s δ shown in FIG. 7B.

As described above, the value of _s δ is composed of the component _s δ _r due to the rigid body rotation caused by the deflection angle _s θ (0) at x = 0 and the deflection _s δ _e due to elastic deformation. Therefore, the value is calculated more easily by substituting _s θ (0) obtained from Equation 8 into Equation 2 to obtain _s δ _r , further obtaining _s δ _{e in} Equation 3 and taking the two sums. be able to.

Then, “concentrated load Q acting on free end M33 and deformation _s δ _r due to rigid body rotation of S member M3” and “concentrated load Q acting on free end M33 and deflection _s δ _e due to elastic deformation of S member M3” Is derived from Equation 8 and Equation 7, respectively, and the following Equation 9 and Equation 10 are obtained, respectively.

As described above, in the case of the composite structural beam 1 of this embodiment in which the boundary plate 4 and the steel frame 3 are integrated by the welding 41, the elastic deflection δ when the concentrated load Q acts on the free end (M33) of the cantilever type. the formula 6, by superimposing formula 9 and formula 10, it can be seen that can be obtained as _{δ = rc δ + s δ r} + s δ e.

  The constitutive equation that has been seen so far has been developed as a relationship between the concentrated load Q acting on the free end M33 and the deformation of each part constituting the deflection using the reference model M0. Therefore, further improvement is required.

  In the so-called general-purpose structural design program, since the stress analysis of the frame is performed according to the bending moment distribution diagram as seen in the middle of FIG. 6, the elastic stiffness of the member is not “the relationship between force and deformation” but “burden bending moment and In general, the evaluation is based on the relationship between the member deformation angles.

  When considering not only elastic rigidity but also nonlinearity due to cracking of concrete and yielding of steel, RC member M8 includes “Reinforced Concrete Structural Calculation Standards / Same Commentary, 2012.2 (The Architectural Institute of Japan)” (hereinafter referred to as “RC Standard”). It is assumed that the rigidity reduction rate α conforming to the above) is the most general-purpose means, but the definition of the rigidity reduction rate α is also intended for the “Relationship between the burden bending moment and the member deformation angle”. It has become. That is, when considering a smoother operation of the rigidity evaluation method that has been developed so far, the constitutive equation for evaluating the deformation behavior of the composite structural beam 1 is not “relationship between force and deformation” described above, but “ It is desirable to express as “the relationship between the burden bending moment and the member deformation angle”.

Therefore, as shown in FIG. 7, the member deformation angle ( _rc R) corresponding to the deflection _rc δ of the RC member M8, the deformation _s δ _r due to the rigid rotation of the S member M3, and the deflection _s δ _e due to the elastic deformation of the S member M3. , _S R _r , _s R _e ) divided by the length of the associated interval, _rc R = _rc δ / _rc l, _s R _r = _s δ _r / _s l _n , _s R _e = _s δ _It is defined as _e / _s l _n . The elastic stiffness that forms the constitutive equation with the maximum bending moment that causes these member deformation angles is named _rc S, _s S _r , _s S _e in this order. The “relation angle relationship” can be generally expressed as the following Expression 11.

Here, M _e burden bending moment, M _s at the position of x = _rc l shows a burden bending moment at the position of x = 0.

As described above, the structural relationship between the deformation components _rc δ, _s δ _r , _s δ _e derived from the reference model M0 as the starting point and the concentrated load Q acting on the free end (M33) of the composite structural beam 1 is expressed by the equation 6, 9, and 10. Since each of these equations can be deformed in accordance with equation 11, (member) elastic rigidity _rc S, _s S _r , _s S _e in the equation is expressed by the following equations 12, 13, 14 respectively. Can be expressed as

_Rc S in Expression 12 is a member elastic rigidity based on an elastic solution when the RC member M8 is interpreted as a cantilever having a length _rc l under the stress condition as shown in FIG. 8, and _s S _{e in} Expression 14 is a member elastic stiffness based on elastic solutions when interpreted as a cantilever of length _s l _n that acts concentrated load Q of the S element M3 to the free end M33.

The elastic modulus of the member of the composite structural beam 1 additionally takes into account the deformation component given by the second equation of Equation 11 according to the burden bending moment M _s at the tip 121 (x = 0) of the material end 12. It is evaluated by that.

  The evaluation model M1 of the composite structural beam 1 shown in FIG. 1 interprets this additional portion as a bending spring M13, and connects the RC beam M12 as a reinforced concrete model and the S beam M11 as a steel frame model. Is equivalent to

  However, as is clear from the bending moment distribution diagram in the lower part of FIG. 1 and the bending moment distribution diagram in the lower part of FIG. 8, the bending moment distribution in the material end portion 12 does not coincide in this modeling. .

For this reason, the member elastic stiffness _rc S of the RC beam M12 shown in Expression 12 is expressed as an apparent value of the equivalent member elastic stiffness obtained from the deformation behavior under the original stress condition according to the reference model M0. Can be considered a thing. However, this equation 12 representing the apparent member elastic rigidity _rc S includes the length (the distance between the embedding start end M31 and the end M32) _s 1 _b of the embedded portion 3b of the steel frame 3, It can be said that the effect of embedding the steel frame 3 in the portion 12 can be expressed. In short, Equation 12 does not represent only the reinforced concrete structure, but accurately represents the steel-framed reinforced concrete structure.

By the way, since this member elastic stiffness _rc S is different from the normal “member elastic stiffness of a reinforced concrete structure cantilever of length _rc l”, the composite structural beam 1 is used as an evaluation model M1 shown in FIG. Each time, it is necessary to directly input the value calculated using Equation 12.

On the other hand, the member elastic stiffness _s S _e of the S-shaped beam M11 shown by the equation 14 is “concentrated load Q at the free end M33, as is apparent from the comparison of the bending moment distribution diagrams of the lower stage of FIG. 1 and the middle stage of FIG. There is no difference from the cantilever with a steel structure of length _s l _{n on which} is applied, and this also appears as a form of the formula.

As described above, the (model) elastic stiffness for performing the primary design shown in FIG. 2 can be obtained using the evaluation model M1 indicating “the relationship between the burden bending moment and the member deformation angle”. Specifically, “stress calculation” is performed using the elastic stiffness _rc S, _s S _r , _s S _e obtained using the evaluation model M1, and “long-term and short-term stress due to a combination of load and external force” is calculated. Determine. Based on the calculated stress, “stress level confirmation” is performed. Here, in the “confirmation of stress level” step, calculation of cross section for bending, calculation for shearing, confirmation of adhesion, calculation of concentrated reinforcement 7, calculation of boundary plate 4, confirmation of bearing stress level of concrete 8, etc. Since there are various designs (examination), it will be implemented as necessary. Further, the deformation increase coefficient can be examined.

  Subsequently, the case where the evaluation model M1 is used for setting the restoring force characteristic necessary for the secondary design shown in FIG. 2 will be described.

In the secondary design, when evaluating the member rigidity of the composite structural beam 1 with nonlinearity, as in the case of evaluating the member elastic rigidity, the deflection δ = δ ( _−s l _n ) at the free end is As shown in FIG. 7, the deflection _rc δ of the RC member M8, the deformation _s δ _r of the exposed portion (3a) section due to the rigid rotation of the S member M3, the deflection of the exposed portion (3a) section due to the elastic deformation of the S member M3. with _s [delta] _e, it is assumed that can be expressed as _{δ = rc δ + s δ r} + s δ e. That is, the non-linear behavior (restoring force characteristic) of the composite structural beam 1 is obtained by adding non-linearity corresponding to each situation to each deformation component as shown in FIG. And

However, as shown in the above formulas 12-14, the member elastic stiffness _rc S, _s S _r , _s S _{e that} is the starting point of each nonlinear behavior is _specially expressed in the expression “relationship between burden bending moment and member deformation angle”. Therefore, the following description is also developed based on FIG. 10B, which is “Relationship between burden bending moment and member deformation angle” equivalent to FIG. 10A. 10A and 10B exemplify the case of the RC hinge type in which the composite structural beam 1 to be subjected to rigidity evaluation assumes a plastic hinge at the terminal end 122 of the material end portion 12. .

First, as shown in FIG. 10B, the member rigidity of the RC beam M12 is assumed to exhibit a trilinear rigidity decrease with “bending crack generation point” and “bending yield point” as singular points. That is, the deformation behavior as can be evaluated like a normal reinforced concrete beam, flexural crack moment _rc M _c in the figure, the yield moment _rc M _y, and stiffness reduction rate alpha _y at the yield point are all provisions of RC criteria It is considered to be obtained by the following formula 15-17.

Here, _c sigma _B compressive strength of the concrete, _rc Z _e is section modulus partial loss of steel 3 is that rebar is considered without considering the RC Zohari M12, a _t is the cross-sectional area of the tensile reinforcement, _r sigma _y yield strength of main reinforcement are, _rc d is blame valid RC Zohari M12, n is concrete and main reinforcement Young's modulus ratio, p _t is the tensile reinforcement ratio RC Zohari M12 which partial loss of steel 3 is not considered, _rc D indicates the beam of the RC beam M12.

At this time, Shiasupan a required upon derivation of alpha _y is the length _rc l of Zaitan portion 12. This is because, as shown in FIG. 8, the bending moment distribution diagram occurring RC member M8 constituting the reference model M0 is considered reasonable from the fact that the same similar roughly the cantilever Shiasupan _rc l.

Note that Equation 16 is an approximate expression. If this is strictly written, the following equation 16A is settled.

Here, _c sigma _B compressive strength of the concrete, a _t tensile cross-sectional area of the reinforcing bars, _r sigma _y is the yield strength of the main _{reinforcement, g 1 = j t / rc} D, j t is tension and compression reinforcement distance between centers of gravity, _rc D is sei Ryo RC Zohari _{M12, q = p t r σ} y / c σ B, p t is the tensile reinforcement ratio RC Zohari M12 which partial loss of steel 3 is not considered (p _t = a _t / ( _rc b _rc D)), _rc b indicates the beam width of RC beam M12 (both refer to RC standards).

Next, it is assumed that the bending spring M13 exhibits trilinear non-linearity similar to that of the RC beam M12 as represented in FIG. This is because the deformation component is proportional to the deflection angle _s θ (0) of the S member M3 at the tip M121 (x = 0) of the RC member M8 in the process of deriving the member elastic rigidity described above, and _s θ at that time This is because the value of (0) starts from the continuous condition with the deformation of the RC member M8. That is, the graph of the bending spring in FIG. 10B shows that “the rigidity decrease as the bending spring M13 is dependent on that of the RC beam M12”, and “the shear force acting on the free end M33 (FIG. 10A)” relationship deformation _s [delta] _r by the rigid rotation of the concentrated load) Q and S member M3 is, behave in synchronization with the decrease in rigidity of the RC Zohari M12 "as depicted in" relationship bending moment and the member deformation angle " There, a point corresponding to the bending crack moment _rc M _c and yield moment _rc M _y of RC Zohari M12 have been obtained by multiplying the _rc M _c and _rc M _y respectively (M _s / M _e). Further, it is assumed that α _y obtained from Expression 17 can be diverted for the rigidity reduction rate at the yield point obtained in this process.

The skeletal curve of the S-shaped beam M11 shown in FIGS. 10 (a) and 10 (b) is “the length _s l _n at which the concentrated load Q acts on the free end M33”, as in the case of inducing the elastic rigidity of the member. The deformation behavior of “cantilever with steel structure” is no different.

Further, when the yield strength _s Q _y at the bending yield of the S beam M11 in FIG. 10A is larger than the bending strength _rc Q _y at the bending yield of the RC beam M12 in FIG. 1 becomes the RC hinge type, and when it is small, it becomes the S hinge type. Here, the “S hinge type” refers to a case where a plastic hinge is assumed at the embedding start end (M31) of the steel frame 3.

  In short, by using the evaluation model M1, whether the position where the plastic hinge occurs during nonlinear behavior is the end 122 of the material end 12 (RC hinge type) or the embedded start of the steel frame 3 (M31) (S hinge type) can be automatically determined from the relationship between force and deformation.

Moreover, skeleton curve of S Zohari M11 is assumed to take on a non-linearity via the yield moment _s M _y, this time, bilinear model and singularity yield moment _s M _y only one point, or yield It will be may be expressed by either trilinear model that specifically point two points moment _s M _y and fully plastic moment _s M _p. 10A and 10B illustrate the case of a trilinear model.

  As described above, the restoring force characteristic for performing the secondary design shown in FIG. 2 can be obtained by using the evaluation model M1 indicating “the relationship between the burden bending moment and the member deformation angle”. Specifically, using the restoring force characteristic obtained using the evaluation model M1, “calculation of retained horizontal proof stress” or the like is performed. Based on the calculated retained horizontal proof stress, “other studies (guaranteed design, etc.)” are conducted. Here, the “other study (guaranteed design, etc.)” steps include prevention of unexpected hinge formation, prevention of shear failure, confirmation of shear reliability considering the effect of adhesion failure, calculation of concentrated reinforcing bars, boundary Since there are various designs (examinations) such as the design of the plate 4 and the prevention of the bearing bearing failure of the concrete 8, it is executed as necessary.

  Hereinafter, a composite structural beam 1A having a different form from the composite structural beam 1 of the above-described embodiment will be described with reference to FIG. The description of the same or equivalent parts as the contents described in the above embodiment will be described with the same terms and the same reference numerals.

  In the embodiment, the steel frame 3 and the boundary plate 4 are integrated by the welding 41. In contrast, in the composite structural beam 1A of the first embodiment, the steel frame 3 and the boundary plate 4 are not dynamically integrated. That is, there is a difference in some of the detailed specifications.

  Specifically, the boundary plate 4 is disposed so as to surround the outer periphery of the steel frame 3 as shown in the cross-sectional view of FIG. 11A (see the direction of arrows AA in FIG. 3). For example, the boundary plate 4 is formed by punching a hole that is slightly larger than the outer shape of the steel frame 3 in the center of a rectangular steel plate that is substantially the same as the end face shape of the material end portion 12.

  And the clearance gap 42 is formed between the boundary plate 4 and the steel frame 3 penetrated through it. The gap 42 is formed along the entire circumference of the cross section of the steel frame 3 as shown in FIG.

  For this reason, the steel frame 3 and the boundary plate 4 are not dynamically integrated. It should be noted that welding to the extent of temporary fixing performed to improve workability and assembly accuracy during assembly is allowed because it does not lead to mechanical integration.

  Most of the evaluation model (hereinafter referred to as “non-weld model”) of the composite structural beam 1A is the evaluation model M1 (hereinafter referred to as “weld model”) of the composite structural beam 1 described in the above embodiment. Will be the same. Below, only a different part from a welding model is demonstrated.

In the case of the non-welded model, the deflection δ of the composite structural beam 1A when the concentrated load Q is applied to the free end M33 is expressed as δ = _rc δ + _s δ _r + _s δ _e as in the case of the welding model. Think about it.

In the case based on the reference model M0, the transmission of force via the pin does not differ depending on the presence or absence of welding. Therefore, the deflection _rc δ of the RC member M8 and the deflection _s δ _e due to elastic deformation of the S member M3 are the welding model. It is equivalent to that of.

  On the other hand, since a gap 42 exists between the boundary plate 4 and the steel frame 3 and is not welded at the tip 121 of the material end portion 12, both deflection curves are at the pin at this position (x = 0). It is not considered that the continuous condition is satisfied. This is the difference between the welding model and the non-welding model.

Therefore, assuming continuous conditions at the position (x = _s l _b) of termination M32 of S member M3 that other pins are arranged as shown in FIG. 12 is satisfied, deflection curve of the S member M3 _s When δ (x) and the deflection angle _s θ (x) are derived, the following equations 18 and 19 are obtained.

Here, as in the welding model, by substituting x = _−s l _n into the second equation of Equation 18, the deflection δ at the free end (M33) of the composite structural beam 1A can be obtained. Further, _s δ _r derived by substituting _s θ (0) obtained from Equation 19 into Equation 2 can also be calculated by adding _rc δ and _s δ _e . When the relationship between the “concentrated load Q acting on the free end (M33) and the deformation _s δ _r ” required at this time is summarized, the following Expression 20 is obtained.

The replacement with the evaluation model expressed as “the relationship between the burden bending moment and the member deformation angle” can be explained as follows through the above-described formula 11. The structural relationship between the deformation components _rc δ, _s δ _r , _s δ _e derived from the reference model M0 as the starting point and the concentrated load Q acting on the free end (M33) of the composite structural beam 1A Are defined as 6, 20, and 10, respectively. Since each of these equations can be deformed in accordance with Equation 11, the (member) elastic rigidity _rc S, _s S _r , _s S _e in the equation is expressed as Equations 12, 21, and 14, respectively. It will be possible. In addition, about Formula 12 and 14, what was described in the said embodiment was described again.

Thus, the weld model and the non-weld model differ only in the member elastic stiffness _s S _r of the bending spring M13 among the member elastic stiffnesses _rc S, _s S _r , and _s S _e . For this reason, when the examination between the welding model and the non-welding model is switched, the examination can be easily reconsidered only by switching the member elastic rigidity _s S _r of the bending spring M13.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Hereinafter, the results of confirming the validity of the evaluation model of the composite structural beam 1, 1 </ b> A described in the embodiment and Example 1 in comparison with the experimental value will be described with reference to FIGS. 13 and 14. In addition, since the welding model which is the evaluation model M1 of the composite structural beam 1 and the non-weld model which is the evaluation model of the composite structural beam 1A can be switched only by changing the setting of the bending spring M13 of the evaluation model M1, in the following, In some cases, the evaluation model M1 may be described collectively using the symbol M1.

  As described above, the member rigidity of the bending fracture type composite structural beam 1, 1 </ b> A is obtained by creating the evaluation model M <b> 1 as shown in FIG. It can be considered that the behavior can be evaluated even in the non-welded model (composite structure beam 1A). Even if the plastic hinge is of the RC hinge type formed at the terminal end 122 of the material end portion 12 or the S hinge type formed at the embedding start end (M31) of the steel frame 3, the behavior is shown up to the nonlinear region. It can be said that it can be evaluated.

  In this Example 2, a specimen that has been bent and fractured from a structural experiment conducted to confirm the structural performance of the composite structural beams 1 and 1A is taken, and its positive direction virgin applied envelope and this evaluation method are taken. The validity of the method for evaluating the member rigidity and the design method for the composite structural beams 1 and 1A described above will be described by comparing with the skeleton curve obtained by (an evaluation method using the evaluation model M1).

13 (a) and 13 (b), regarding the two specimens exhibiting bending fracture among the specimens, “concentrated load Q acting on the free end and deflection at the free end (M33) position (hereinafter,“ "Free end displacement")) δ relationship "and" Concentrated load Q acting on the free end and deflection at the tip 121 position of the material end 12 (hereinafter referred to as "material end tip displacement") _rc δ relationship " 3 shows the correspondence between the calculated value using the evaluation model M1 and the experimental value.

  Here, these two bodies are both RC hinge type test bodies. FIG. 13 (a) is a verification result of a welding model (composite structure beam 1), and FIG. 13 (b) is a non-weld model (composite structure). The verification result of the beam 1A) is shown.

  As shown in FIG. 13, all the calculated values by the evaluation model M1 show the transition of the experimental value of the free end displacement δ with the gradual increase of the concentrated load Q, regardless of whether or not the welded joint between the boundary plate 4 and the steel frame 3 is present. Thus, it can be seen that it was captured with relatively good accuracy. As a result, it can be said that the method formulated by providing a difference in the continuous condition between the RC member M8 and the S member M3 depending on the presence or absence of welding was appropriate.

Further, when the compatibility of the calculated value and the experimental value regarding the transition of the material end tip displacement _rc δ is examined, a relatively good correspondence can be seen for this. As described above, when the material end tip displacement _rc δ is obtained based on the reference model M0, the presence or absence of welding has no effect on the value of _rc δ in the elastic region or in the nonlinear region. Yes, there is no difference between what the solution of the welding model and the solution of the non-welding model are intended for.

  Therefore, based on the above results in which the correspondence between the calculated value and the experimental value was relatively good, it was determined that “the deformation in this section was derived under a stress condition according to the reference model M0”, and that “the presence or absence of welding at that time It was a reasonable premise that we did not reflect the impact of

Regarding the behavior in the non-linear region, the length _rc l of the material end 12 is adopted as the shear span a obtained at the time of solution, applying the rigidity reduction rate α _y of the RC standard mutatis mutandis based on the above assumption. However, this result is considered to indicate the validity of this assumption.

Furthermore, bending in relation to the reduction in rigidity ratio alpha _y at yield, "the value obtained to the subject an RC member M8, constitutive law bending spring M13 representing a deformation _s [delta] _r by the rigid rotation of the S member M3 Is assumed to be diverted, "this assumption is also appropriate when looking at the correspondence between the calculated value and the experimental value for the free end displacement δ of the specimen.

Subsequently, FIG. 14 shows, as in FIG. 13, “Relationship between concentrated load Q acting on the free end and free end displacement δ” and “free end” for the two test pieces that exhibited bending fracture among the test pieces. 4 shows the correspondence between the calculated value and the experimental value found in “Relationship between concentrated load Q acting on material and tip end tip displacement _rc δ”. Here, although these two bodies are all non-welded models, FIG. 14A shows the verification result of the RC hinge type, and FIG. 14B shows the verification result of the S hinge type.

Looking at the results of FIG. 14, similar to the results shown in FIG. 13, all the calculated values showed relatively good transitions in the experimental values with respect to the free end displacement δ and the material end tip displacement _rc δ. It can be said that it can be tracked with accuracy.

  The skeletal curve of the test piece of S hinge type shown in FIG. 14B is bent and yielded at the tip M121 (position of the embedded start end M31 of the S member M3) prior to the end M122 of the RC beam M12. FIG. 10B shows an ordinary S-shaped beam M11 that exhibits a trilinear nonlinear behavior having “bending yield” and “total plasticity of the cross section” as singular points. For this reason, the result of the tetra linear type which added the bending crack point of the terminal M122 of RC beam M12 finally was obtained.

  As described above, the compatibility between the calculated value and the experimental value is relatively good. As a result, the evaluation method using the evaluation model M1 has an accuracy that can cope with a change in the assumed hinge position. It is thought that.

  Further, in FIG. 14B, the calculated value is zero after the total plasticization of the cross section of the S member, while the experimental value continues to increase thereafter, and in the large deformation region, the calculated value and the experimental value. There is a slight gap between This increase in the experimental value inevitably works in the large deformation area when the vertical displacement is applied to the free end of the cantilever beam as in this experiment. Therefore, it is considered that the validity of this stiffness evaluation method is not denied.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Hereinafter, a method for designing a composite structure in a form different from the composite structural beams 1 and 1A of the embodiment or Example 1 will be described. Note that the description of the same or equivalent parts as those described in the embodiment or other examples will be given with the same terms and the same reference numerals.

  The composite structure described in Example 3 is a composite structure column whose column base is a material end. That is, the material end 12 described in the embodiment or Examples 1 and 2 is joined to the floor instead of the column 21.

  Most of the evaluation model of the composite structure column in which the beam is changed to the column is the same as the evaluation model M1 of the composite structure beam 1 or 1A described in the above embodiment or Example 1. Below, only a different part from the case where the evaluation model M1 of the composite structure beams 1 and 1A is used is demonstrated.

Among the equations described in the above embodiments, the only equation unique to the beam is equation 15-17. In other words, the bending crack moment _rc M _c , yield moment _rc M _y , and stiffness reduction rate α _{y at} the yield point when calculating restoring force characteristics (nonlinear behavior) using the evaluation model M1 are also applied to columns other than beams. Replace with the following applicable equations 22-24.

Where _c σ _B is the compressive strength of the concrete, _rc Z _e is the section modulus considering the rebar without considering the cross-sectional defect of the steel frame at the end of the material, N is the axial force acting on the column, and _rc D is the end of the material G ₁ = j _t / _rc D, j _t is the distance between the centers of tension and compression bars, q = p _{t r} σ _y / _c σ _B , p _t is the end of the material that does not consider the cross-sectional defect of the steel frame tensile reinforcement ratio _{(p t = a t / (} rc b rc D)), the cross-sectional area of a _t tensile reinforcement, _r sigma _y is the yield strength of the main _{reinforcement, η 0 = N / (rc} b rc D c σ B ), _Rc b is the width of the end of the material, n is the Young's modulus ratio of concrete and main reinforcement, a is the shear span, and _rc d is the effective end of the material (both refer to the RC standard).

  In this way, even if the composite structure is not a beam but a composite structure column, the stiffness evaluation method and the design method described above are applied using the same evaluation model as the evaluation model M1 described in the above embodiment. can do.

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  Hereinafter, a composite structural beam 1B having a form different from the composite structural beams 1 and 1A of the embodiment or Example 1 will be described with reference to FIG. Note that the description of the same or equivalent parts as those described in the embodiment or examples will be given with the same terms and the same reference numerals.

  In the embodiment and Example 1, the composite structural beams 1 and 1A having the boundary plate 4 have been described. In Example 4, the composite structural beam 1B having no boundary plate 4 will be described.

  As shown in the upper part of FIG. 15, the composite structural beam 1 </ b> B has a central part 11 mainly formed by the steel frame 3 and a material end part 12 of a reinforced concrete structure in which the end part of the steel frame 3 is embedded. .

  Further, no plate is arranged at the boundary between the central portion 11 and the material end portion 12, and the main bar 5 is fixed near the tip of the material end portion 12. In FIG. 15, fixing using the disk-shaped fixing plate 53 is illustrated, but the fixing is not limited thereto, and for example, the tip of the main muscle 5 may be processed into a hook shape.

  On the other hand, instead of the boundary plate 4, concentrated reinforcing bars 7 and 7 are arranged in both the vicinity of the tip (M121) of the material end 12 and the end 3c of the steel frame 3 in the composite structural beam 1B.

  And the reference model M10 of the composite structural beam 1B having such a structure is different in the pin support position from the reference model M0 described in the above embodiment, as shown in the lower part of FIG.

  That is, in the reference model M0 described in the above embodiment, the embedding start end M31 and the end M32 of the S member M3 in the material end portion 12 are pin-supported on the RC member M8. In contrast, in the reference model M10 of the fourth embodiment, pins are supported on the RC member M8 at the positions of the two concentrated reinforcing bars M71 and M72.

  Here, the pin position (M72) on the terminal M122 side of the RC member M8 is the same as the position (M32) of the reference model M0 of the above embodiment, but the pin position on the tip M121 side of the RC member M8 ( M71) moves to the inner side (terminal M122 side) of the RC member M8 than the position (M31) of the reference model M0 of the above embodiment.

When the formula is developed using the reference model M10 of the composite structural beam 1B set as described above and an evaluation model is derived in the same manner as in the above embodiment, it is expressed by the formula 12 described in the above embodiment. The elastic rigidity _rc S of the RC beam M12 and the equations 4, 5, and 6 that are the starting points for its derivation change as the pin position moves from M31 to M71. However, the change can be easily adapted only by reflecting the movement of the pin position in the normal beam theory, and the derivation process of the elastic rigidity _rc S is the same as that of the composite structure beam 1 described in the above embodiment. It will not be different.

Therefore, also the elastic stiffness _rc S of the composite structural beam 1B of the present embodiment 4, the influence of _s l _b (the distance between the buried start M31 and end M32) length of the embedded portion 3b of the steel 3 is reflected become.

Similarly, the elastic stiffness _s S _r (formula 13 of the embodiment) related to the deformation due to the rigid rotation of the S member M3 in the reference model M10 is also changed. The derivation process is the same as that of the embodiment. This is the same as the development described in.

In short, the deflection curve _rc δ (x) and the deflection angle _rc θ (x) of the RC member M8 corresponding to the equations 4 and 5 with respect to the reference model M10 are _derived according to the beam theory, and the composite structure beam 1A of Example 1 is used. Similarly, if the deflection angle _s θ (x) of the S member M3 corresponding to Equation 19 is obtained from the continuous condition at the terminal M32 of the S member M3, _s θ (0) of the reference model M10 can be obtained. Then, by substituting _s θ (0) into Equation 2, the relationship between force and deformation corresponding to Equation 20 is derived. The subsequent expansion can be easily performed by via Equation 11, so that the elastic stiffness _s S _r of the bending spring M13 evaluation model M1 in accordance to the reference model M10 is obtained.

As described above, if the reference model M10 is constructed after appropriately adjusting the position of the pin support according to the structure of the composite structural beam 1B to be analyzed, and the beam theory is applied thereto, the composite structural beam described above is obtained. The elastic rigidity _rc S, _s S _r of the evaluation model M1 according to the reference model M10 can be obtained by the same derivation process as 1, 1A. This becomes the evaluation model M1 of the composite structural beam 1B.

In other words, the embedded composite structural beams 1, 1A, 1B are constructed as reference models M0, M10 in accordance with their detailed specifications, and after passing through a derivation process based on the beam theory, both become evaluation models M1. Can be replaced. The difference in the detailed specifications at this time is expressed as the values of the elastic stiffnesses _rc S and _s S _r .

  Other configurations and functions and effects are substantially the same as those of the above-described embodiment or other examples, and thus description thereof is omitted.

  The embodiment of the present invention has been described in detail above with reference to the drawings. However, the specific configuration is not limited to this embodiment or example, and the design changes are within the scope of the present invention. Are included in the present invention.

  For example, in the said embodiment and Example, although the composite structure (1, 1A, 1B) which has the material edge parts 12 and 12 in both ends was demonstrated, it is not limited to this, One end of steel materials Even when only the material end 12 is embedded and the other end is exposed, an evaluation model can be derived from a reference model created accordingly.

  Moreover, in the said embodiment and Example, although composite structure beam 1,1A, 1B was demonstrated as a composite structure, it is not limited to this, For example, as demonstrated in Example 3, a column base is a material. It may be a composite structure column that is an end.

  Furthermore, in the said embodiment, although the structure which fixes the front-end | tip 52 of the main reinforcement | strength 5A-5F which penetrated the boundary plate 4 with the nuts 51 and 51a was demonstrated, it is not limited to this, The material of the boundary plate 4 A configuration in which a nut fixed to the surface on the end 12 side by welding is fastened or a tip of the main bar is directly fixed to the boundary plate 4 by welding may be employed.

  Moreover, in the said embodiment and Example 1, although the boundary plate 4 demonstrated manufacturing with one steel plate, it is not limited to this, It can also manufacture combining a some steel plate.

1,1A, 1B Composite structural beam (composite structure)
11 Central part 12 Material edge part 3 Steel frame (steel material)
3c Terminal 4 Boundary plate 41 Weld 5A-5F, 5 Main bars 51, 51a Nut 52 Tip 6 Shear reinforcement 7 Concentrated reinforcement 8 Concrete

Claims (13)

A steel material that forms a central portion and is partially embedded in the material end portion, a main bar disposed substantially parallel to the steel material at the material end part, and an axial interval so as to surround the steel material and the main bar A composite structure formed in a long shape by a central portion of a steel structure and a material end portion of a reinforced concrete structure, comprising a plurality of shear reinforcement bars arranged and concrete filled in the material end portion. A design method,
The central part is an elastic-rigid rod-shaped steel frame model based on the steel material, and the material end is an elastic-rigid rod-shaped reinforced concrete model based on reinforced concrete in which the steel material is embedded,
An evaluation model in which the steel model and the reinforced concrete model are combined by an elastic rigid bending spring based on a rigid body rotation of the steel material is set,
A method for designing a composite structure, wherein a structural design is performed using the evaluation model. A steel material that forms a central portion and is partially embedded in the material end portion, a boundary plate that is disposed at a boundary between the central portion and the material end portion, and a material plate that is disposed substantially parallel to the steel material end portion. A main bar whose tip is fixed to the boundary plate, a plurality of shear reinforcing bars arranged at intervals in the axial direction so as to surround the steel material and the main bar, and concrete filled in the end part of the material A method of designing a composite structure formed in an elongated shape by a central portion of a steel structure and a material end portion of a reinforced concrete structure,
The central part is an elastic-rigid rod-shaped steel frame model based on the steel material, and the material end is an elastic-rigid rod-shaped reinforced concrete model based on reinforced concrete in which the steel material is embedded,
An evaluation model in which the steel model and the reinforced concrete model are coupled by an elastic rigid bending spring based on a rigid body rotation of the steel material provided at the position of the boundary plate is set.
A method for designing a composite structure, wherein a structural design is performed using the evaluation model.   3. The method for designing a composite structure according to claim 1, wherein the expression representing the elastic rigidity of the reinforced concrete model includes a length of a steel material embedded in a material end portion. 4. The method for designing a composite structure according to claim 2, wherein the elastic rigidity of the reinforced concrete model is represented by the following expression including the length of a steel material embedded in the end portion of the material.
Where _rc S is the elastic stiffness of the reinforced concrete model, _c E is the Young's modulus of the concrete, _rc I _e is the equivalent moment of inertia of the reinforced concrete model, _s l _n is the length of the center, and _rc l is the end of the material The length, _s l _b , indicates the length of the steel material embedded at the end of the material.   When there is a change in the detailed specification of the composite structure, the evaluation model is set by changing the reference model corresponding to the change to the reinforced concrete model obtained by developing based on the beam theory and the elastic rigidity of the bending spring. The method for designing a composite structure according to any one of claims 1 to 4, wherein:   The method for designing a composite structure according to claim 2 or 4, wherein when the detailed specification of the composite structure is changed, only the elastic rigidity of the bending spring is changed to set the evaluation model. .   The composite structure design method according to claim 2, wherein a continuous condition is set at the position of the boundary plate to determine the elastic rigidity of the bending spring. The method for designing a composite structure according to claim 7, wherein the elastic rigidity of the bending spring is expressed by the following equation.
Where _s S _r is the elastic stiffness of the bending spring, _c E is the Young's modulus of concrete, _rc I _e is the equivalent moment of inertia of the reinforced concrete model, _s l _n is the length of the center, and _rc l is the end of the material The length of _s l _b indicates the length of the steel material embedded in the material end.   5. The method for designing a composite structure according to claim 2, wherein a continuous condition is set at a position of a terminal end of the steel material to obtain an elastic rigidity of the bending spring. The method for designing a composite structure according to claim 9, wherein the elastic rigidity of the bending spring is expressed by the following equation.
Where _s S _r is the elastic stiffness of the bending spring, _c E is the Young's modulus of the concrete, _rc I _e is the equivalent secondary moment of the reinforced concrete model, _s E is the Young's modulus of the steel material, and _s I is the cross section of the steel model 2 Next moment, _s l _n is the length of the center, _rc l is the length of the material end, and _s l _b is the length of the steel material embedded in the material end.   The method for designing a composite structure according to any one of claims 1 to 10, wherein nonlinear behavior is set in at least one of the reinforced concrete model, the bending spring, and the steel frame model.   The method for designing a composite structure according to claim 11, wherein the nonlinear behavior of the bending spring is set to a trilinear type equivalent to the nonlinear behavior of the reinforced concrete model.   13. The method according to claim 1, wherein whether the plastic hinge at the time of nonlinear behavior is generated at a terminal end of the material end or an embedding start end of the steel material is determined from a relationship between force and deformation. A method for designing a composite structure according to 1.