JP2018105091A - Method of constructing artificial ground on subbasement type road - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct an artificial ground on a subbasement type road at low cost without completely cutting off traffic in service.SOLUTION: A span length of a SPC girder 3 which is designed as a simple girder with a distance L of earth retaining walls 2a, 2b on both the sides of a subbasement type road as the span length and in which a steel frame material is disposed on the compressed side is shorter than l/2; a connecting steel frame 32 projecting from the end surface and a sheath 34 passing a connecting PC steel material therethrough are provided at the tip end of the SPC girder 3. The SPC girder 3 is stretched from the earth retaining walls 2a, 2b to a temporary pad 15 provided at the center of the road. The connecting steel frames 32 are connected to each other; concrete is pored and cured in the connecting part; the connecting PC steel material is inserted into the sheath 34 to introduce prestress to make them integrally connected. The temporary pad 15 is removed, so that the simple girder is formed between the earth retaining walls 2a, 2b. A number of the SPC girders 3 are constructed on the road to construct an artificial ground 10 on the subbasement type road.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for constructing an artificial ground without completely blocking traffic on an upper part of a semi-underground road and a precast concrete girder provided with a steel material on the compression side used for the method.

Expressways that carry automobile traffic in large cities have been trying to modernize urban traffic by constructing elevated roads on existing roads due to site difficulties, or by constructing semi-underground roads by removing the moat water It was.
However, the retaining wall of the semi-underground road has deteriorated over the years, and the peeling of concrete and the corrosion of reinforcing bars have become remarkable. In addition, the design standards at the time of construction do not assume a direct earthquake with a seismic intensity of 7, and there is a high possibility that the expressway that is the lifeline will be damaged by the earthquake. The impact will be enormous, and it is inevitable that the economy and civic life will be severely affected.

Renovation is necessary because the reverse T-type retaining wall of semi-underground roads in the city is old and the design strength is low. In order to effectively widen the width of the road and to use the sky above the road in accordance with this renovation work, it is considered to construct an artificial ground on the road.
In constructing artificial ground on a semi-underground road, it is necessary to bridge girders between retaining walls on both sides of the road, but the stagnation and stoppage of urban traffic has a great impact on economic activities. In renovation work, etc., no full closure is permitted, and it is necessary to secure at least one upper and lower lane. Also, if an accident such as a fallen bridge occurs during construction, it can be fatal, and this should not be the case, so it must be a construction method that allows safe and reliable construction.
Furthermore, since the usage height over the road is limited so that it can be safely driven without obstructing the visibility of the driver of the car, it is required to make the height of the girder crossing the road as low as possible. .

  The span length (span), which is the distance between retaining walls of existing semi-underground roads that are used to construct girders for the construction of artificial ground, is about 40-50m in the opposite four lanes. For the span, a steel frame steel material is arranged as a compression steel material on the compression side of the cross section of the precast concrete disclosed in Patent Documents 1 and 2 developed by the inventors of the present application, so that a large prestress can be introduced. A girder with a structure that can lower the girder height and reduce the weight of the girder by reducing the weight of the girder (hereinafter referred to as an SPC girder) is suitable because it can be constructed in a short period of time. Conceivable.

Japanese Patent No. 3703760 Japanese Patent No. 5706656

In order to build an artificial ground on a semi-underground road without completely stopping the road traffic, it is a safety work to secure the work zone W by securing one-lane traffic on one side and blocking other traffic It is considered the most reasonable to carry out. Therefore, a temporary support base such as a support or support is provided in the middle part between the retaining walls, and PC girders are installed one side at a time from the retaining wall to the temporary support base. It is necessary to integrate them.
However, a precast concrete girder (SPC girder) in which steel frame steel materials shown in Patent Documents 1 and 2 designed as simple girders with a retaining wall length (span) as a compressed steel material is divided into two halves. After laying between the retaining walls between the retaining walls and connecting and integrating them at the center of the girder, the temporary retaining base is removed to form a simple girder spanned between all the retaining walls. However, cutting the central section of the beam where the stress is maximum and cutting the connection section will lose the prestress of the central section that is most often applied. The design cross-section of the simple girder that can not withstand the load, and therefore the cross-section must be enlarged, and the SPC that lowers the girder height and lightens the girder's own weight to reduce the burden on the lower structure. Take full advantage of girder strength The ones that can not be bet.

  The present invention makes it possible to construct an artificial ground on a semi-underground road at a low cost while clearing the above-described problems, and at least one up and down without completely blocking the road traffic in service. SPC girder designed as a simple girder with span as the span length (span) when constructing artificial ground by spanning a girder on a semi-underground road with a width of around 40-50m while allowing lane facing traffic This makes it possible to divide and work with the same girder height without increasing the girder height.

This is a method of constructing artificial ground on a semi-underground road with retaining walls on both sides. Precast concrete PC girders (SPC girders) with steel frames on the compression side are distances between retaining walls (L) The cross section is designed as a simple girder having a span length as a span girder, and this section is an SPC girder having a girder length less than half the span length (L / 2), and a connecting steel frame projecting from the front end surface to the front end portion; Temporary cradle with a sheath for connecting PC steel, securing at least one lane in the upper and lower lanes, securing a work zone as the other traffic stop, and installing the SPC girder from one retaining wall to the center of the road Bridge between the doors, change the working lane by switching the traffic lane, change the work zone, and place the SPC girder from the other retaining wall to the temporary receiving stand so as to face each other, and the connecting steel frame protruding from the tip of the SPC girder For connecting together and for connecting PC steel materials Connected PC steel material is inserted and disposed in the base, and concrete is placed between the SPC girders facing each other and hardened, and the connected PC steel material is tension-fixed and prestressed to provide the connection steel frame and the connected PC steel material. A semi-underground type characterized in that after the SPC simple girder between the retaining walls with the span length L is formed by forming the composite structure connecting portion including the SPC girder, the temporary support is removed. It is a method of constructing artificial ground on the road.
In addition, after forming the composite connecting portion and connecting and integrating the SPC girders to form the SPC girders between the retaining walls whose span length is L, both ends of the SPC girders are made into the retaining wall with tension by the PC steel material. This is a method of constructing an artificial ground on a semi-underground road that is rigidly connected and then removes the temporary cradle.

The effects of the present invention are listed below.
(1) By dividing the PC girder applied to the span length designed as a simple girder into two parts, providing a temporary cradle in the middle part of the span and linking the girder in half and connecting and integrating at least one side lane Since traffic can be secured and construction can be performed safely, the logistics due to closed roads will not be stagnated, so there will be no impact on the economy.
(2) By dividing the PC girder applied to the span length (span) as a simple girder in two and forming a composite structure coupling part consisting of steel frame coupling and PC steel material coupling at the center part of the girder and integrating them During construction, it is only necessary to provide a temporary stand (support work or support) at the center of the span. The SPC girder designed as a simple girder can keep the girder height low and the weight of the girder is lightweight. Therefore, the burden on the lower structure can be reduced, and the artificial ground can be constructed economically.
(3) PC steel material (pre-tension type PC steel material and post-tension type PC steel material) that is arranged in advance in the split member by connecting PC steel material penetrating through the composite structure connection part to about 1/3 of the span length Since the pre-stress is smoothly transmitted to the central section of the girder and applied to it, the central composite structure connection part becomes a strong structure, and even in the event of a huge earthquake Can be used as a roadway without damaging the damaged car by dropping the girder on the road surface and damaging it, or blocking the road and obstructing earthquake damage recovery activities Is possible.
(4) In the central composite structure connection part, the cross-section is enlarged by providing a puff that increases the girder height, so that it is possible to arrange a large number of connecting steel members and many connected PC steel materials in the connection part. At the same time, the structural strength of the whole girder will be greatly increased, and it will be possible to construct various buildings on the artificial ground, thereby achieving urban diversity.
(5) By connecting both ends of the girder to the retaining wall with PC steel, the SPC girder will bear a part of the total bending moment due to the load, and the bending end will be reduced by the central section. Therefore, it is possible to reduce the steel frame or PC steel material as the central connecting steel material, and to secure a space for arranging the connecting steel material or the connecting PC steel material without increasing the beam height.
(6) Conventionally, the span length (span) of PC simple girder bridges was limited to 30-40m, and the girder height span ratio was limited to 1 / 17.5. The span length (span) can be expanded to 50-70 m by using an SPC girder (no connection part is provided at the center of the girder), and the limit of the girder height span ratio is increased to 1/30 (Patent Document 2: Japanese Patent No. 5706656) Paragraph 0003 and paragraphs 0012 and 0013).
The present invention is applied to a simple girder bridge having a span length (span) of 40 to 50 m while maintaining the characteristics (advantages) of the SPC girder by connecting and integrating the divided members by providing a composite structure coupling portion in the center of the girder. At the same time, it was made possible to construct the upper part of the semi-underground road with a girder height span ratio of about 1/22 to 1/30 and a lower girder height.

(1) Plan view, (2) Front view, (3) Left and right end views and a cross-sectional view of an intermediate portion of an SPC girder. The construction process figure of this invention. Explanatory explanatory drawing of the formation process of a composite structure connection part. (1) Plan view, (2) Front view, (3) Left and right end views and a cross-sectional view of the middle part of an SPC girder in which the upper edge of the connecting part is enlarged to enlarge the girder height. The construction process figure by the SPC girder which expanded the girder height by enlarging the upper edge of a connection part. The expansion explanatory drawing of the formation process of the composite structure connection part by the SPC girder which expanded the upper edge of the connection part and expanded the girder height. The construction process figure by the SPC girder which expanded the lower edge of the connection part and expanded girder height. The expansion explanatory drawing of the formation process of the composite structure connection part by the SPC girder which expanded the lower edge of the connection part and expanded the digit height. The construction process figure which extends the connection PC steel material in a connection part, and fixes it to the upper edge of a SPC girder. The expansion explanatory drawing of the formation process of the composite structure connection part which extends the connection PC steel material in a connection part, and fixes to the upper edge of a SPC girder. The construction process figure which extends the connection PC steel material in a connection part, and fixes it to the lower edge of a SPC girder. The expansion explanatory drawing of the formation process of the composite structure connection part which extends the connection PC steel material in a connection part, and fixes to the lower edge of a SPC girder. The construction process figure which extends the tension steel material in the girder edge fulcrum part on the retaining wall side, and fixes it to a SPC girder. The expansion explanatory drawing of the formation process of the composite structure connection part by the SPC girder which extended the lower edge of the edge part of the connection part girder. Explanatory drawing of the structure which arrange | positions tension steel materials in the retaining wall used as a supporting point of a girder, and connects a girder and the retaining wall rigidly. Figure of bending moment distribution of girder. Explanatory drawing of how to secure a work zone on the road. Sectional drawing along the road of the artificial ground built on the semi-underground type road.

The present invention will be described in detail below with reference to the drawings.
In the present invention, because the place where the artificial ground is constructed is on a semi-underground road, the artificial ground completed on the road covers the driver and looks like a tunnel, giving a feeling of pressure. Therefore, it is necessary to make the height of the girder used as artificial ground as low as possible.
SPC girders (prestressed precast concrete girders with steel on the compression side) can increase the pre-stress amount by increasing the apparent concrete cross-sectional area by placing steel on the compression side of the girders cross section. It has the characteristic that the height of a girder can be made lower than a normal prestressed concrete girder.

FIG. 1 shows an example of an SPC girder used for constructing an artificial ground according to the present invention, showing half of the girder over a semi-underground road, from a factory that manufactures the SPC girder. It is divided into _three units 3U ₁ , 3U ₂ , 3U ₃ in consideration of transportation to the construction site. (1) Plan view, (2) Front view, and (3) Left and right end views and middle part It is sectional drawing. The end surface 3M that is a connecting portion between the units has a quadrangular cross section, and is an SPC girder 3a, 3b in which each unit is integrally joined by pressure bonding using a PC steel material by a post tension method.
Each unit is pre-stressed with PC steel placed and pre-stressed, and the pre-tensioned PC steel 35 becomes a part of the structural strength of the SPC girder and is placed after that. The amount of 35a can be reduced.
This SPC girder has an I-shaped cross section as shown in the bb cross section of FIG. 1 (3), and a steel steel material 31 as a compressed steel material is disposed on the compression side flange. The steel steel material 31 in the illustrated example is arranged over the longitudinal direction of the girder with the L-shaped steel assembly material facing each other. A base (end fulcrum widening portion) 3E placed on the earth retaining wall at the end of the girder unit 3U ₁ is a rectangular parallelepiped, and this part is placed on the earth retaining wall 2 for installation.
End of the leading side girder unit 3U ₃ 3T is a connecting portion that is integrally coupled from the other opposing earth retaining retaining wall at the center of the SPC digits and road installed toward the center of the road, Like the base 3E of the girder unit 3U ₁ , it is a rectangular parallelepiped, and the H-shaped steel as the connecting steel frame 32 projects the length necessary for connection with the other girder from the end surface of the girder unit 3U ₃ , are fixed on the spar unit 3U ₁ is embedded a predetermined length in the.

As shown in FIG. 2, the SPC girders 3a and 3b, in which the above units are connected to each other by a post-tension type PC steel material 35a (not shown) and integrated, are provided on both sides of the semi-underground road 1. The artificial ground 10 is constructed by sequentially laying it on the walls 2a and 2b and the temporary support 15 installed in the center of the road, and connecting and integrating on the temporary support 15 as an SPC simple girder between the retaining walls. To do.
It is indispensable to construct an artificial ground without blocking traffic completely, and it is absolutely necessary to avoid damaging human lives, such as damaging a running car, from one retaining wall 2a. A temporary pedestal 15 such as a support or support is installed in the center of the road between the opposing retaining walls 2b, and a work zone W is formed by blocking one of the upper and lower lanes. By causing the vehicle to run vertically opposite, accidents caused by construction involving a running car are prevented.

FIG. 2 is an overall explanatory diagram of the artificial ground construction process, FIG. 3 is an enlarged view of the connecting portion of the SPC girders 3a and 3b, and the numbers indicating the steps in FIGS. 2 and 3 indicate the state of the same procedure. The construction process will be described with reference to both figures.
As shown in FIG. 2 (1), the SPC girder designed with a simple girder having the retaining wall 2a and 2b as the fulcrum of the girder 3 and the distance (L) between the retaining walls as the span length is substantially half. The SPC girder 3a having a length of L / 2 is divided into three units with a length that can be transported and integrated by crimping and connecting with a post-tension type PC steel material 35a (not shown). It is installed on the wall 2a and the intermediate cradle 15 by an appropriate construction method, for example, a delivery method using a construction girder.
Here, as shown in FIG. 2 (2), the lane that has been the traffic zone T until which the vehicle is traveling is blocked, the lane that has been the work zone W is opened, and the traffic zone T is switched to. The SPC girder 3b is sent out from the opposite retaining wall 2b toward the intermediate temporary receiving table 15, and the leading portion of the SPC beam 3b is placed on and supported by the temporary receiving table 15, and sent out from both the retaining walls 2a and 2b. The connecting steel frames 32 and 32 projecting from the leading portions of the SPC girders 3a and 3b are brought into a butted state.
As shown in FIG. 2 (3), a connecting plate is installed on the connecting steel frame 32, the SPC girder 3a and the girder 3b are connected and integrated, and the periphery of the connecting portion is surrounded by a formwork to form concrete or non-shrink mortar. 33, and after consolidation, a PC structure is inserted into a connection PC steel sheath 34 provided at the top of the SPC girders 3a and 3b to fix the tension, thereby forming a composite structure connection section 36. The beams 3a and 3b are firmly connected and integrated.
When the central cradle 15 is removed as shown in FIG. 2 (4), the SPC girder 3 with a simple girder height designed to be applied to the span length (L) between the retaining walls 2a, 2b. Will be in a state of being overlaid. Since the artificial ground 10 is completed by forming the floor slab 4 on the girders 3, an auxiliary structure of the artificial ground, for example, a ground cover, a railing, etc. is constructed.
Although not shown in the figure, a reinforcing bar is projected from the tip of the SPC girders 3a and 3b in advance, the reinforcing bar is arranged at the connecting part, and the protruding reinforcing bar is connected, and a composite structure including a steel frame, PC steel, and reinforcing bar The connecting portion 36 can also be used.

FIG. 4 shows another example of an SPC girder used for construction of artificial ground, in which the upper edge of the end of the connecting part of the girder is enlarged upward to provide an enlarged part 3F. A sheath 34 </ b> S for inserting the connected PC steel material 34 a is installed in the portion 3 </ b> H. A composite structure connecting portion 36 that firmly connects the SPC girders 3a and 3b is formed by inserting the connecting PC steel material 34a into the sheath 34S provided in the enlarged portions (flicks) 3H of both SPC girders 3a and 3b and fixing the tension. It is a thing.
By providing the enlarged portion 3H, the cross section of the girder is enlarged, and a steel member having a relatively large cross section can be arranged in the composite structure coupling portion 36, and more PC steel materials for coupling can be arranged. Since the overall structural strength can be increased, it is possible to construct a heavy-load building on the completed artificial ground, so that the use of the artificial ground is expanded.
5 and FIG. 6 show the process of passing the beam and the construction process of the composite connection structure 36 in the case of using the SPC girder having the enlarged portion 3H provided at the end shown in FIG. These steps are the same as those shown in FIGS. 2 and 3, except that an enlarged portion 3H is provided at the connection end.
In the example shown in FIG. 7 and FIG. 8, an enlarged portion (splash) 3H at the end of the girder is formed at the lower edge of the SPC girder, and is upside down from the example of FIGS. .

In the example shown in FIG. 9 and FIG. 10, a PC cable is extended as a connecting PC steel material 34 by a relatively long distance from the composite structure connecting portion 36 in the direction of the fulcrum of the girder. The tension is fixed to the extension fixing portion 5 that protrudes from the upper edge of the next unit girder.
In this case, for the tension fixing work of the connected PC steel material at the connecting part in the center part of the girder, the work zone W is provided by blocking the lane in the center part of the road, and the lane in the lane on the left and right retaining wall 2a, 2b side Do not work on the lane T. A plan view of switching between the work zone W and the traffic zone T is shown in FIG.
The extension fixing unit 5 may be protruded to the lower edge side of the SPC beam 3 as shown in FIGS. 11 and 12.

Further, as shown in FIG. 13, the extended fixing portion 5 may be provided on the end surface of the connecting portion of the unit without causing the extended fixing portion 5 to protrude from the upper edge or the lower edge of the girders, and the connected PC steel material may be fixed.
The connected PC steel 34 (secondary PC steel) disposed in the above-described illustrated example, in particular, the composite structure connecting portion 36 illustrated in FIGS. 9 to 13 is the primary PC previously disposed in the unit that is a divided member. Since the steel material (pre-tension type PC steel material 35 and post-tension type PC steel material 35a) and a sufficiently long lap portion are provided, sufficient prestress is applied to the central cross section of the girder. The resulting large bending stress is jointly borne by the secondary PC steel material and the primary PC steel material and transmitted to the fulcrum at both ends of the girder.
Further, in the present invention, it is necessary to observe the principle of securing the work zone W by securing the lane T of one lane and blocking the other lanes, but the primary PC steel and the secondary If the wrap length of the PC steel material is increased, the work of the both-end fixing part 5 of the secondary PC steel material, which is a field work, enters the traffic zone T beyond the work zone W, which is not preferable. Then, considering that the girders after completion of the connection are basically simple girders, as shown in the moment diagram of FIG. 16 (2), in the central section of the girders, up to about 1/3 of the span length. The bending moment is large in the section, but outside the section, the moment decreases to almost half and becomes a small value, so the secondary PC steel is placed in the section of about 1/3 of the span length (L). By doing so, the necessary strength can be obtained and the construction period can be shortened, so that it is reasonable, and therefore, the lap section is preferably set to 1/3 of the span length (L).

  In the example shown in FIG. 14, a lower edge extension 3 </ b> J is formed by extending the lower edge of the end portion of the SPC girder serving as a connecting portion. It is only necessary to abut the lower edge extension portions 3J and provide joints between the lower edge extension portions 3J to fill the joint material. A bed form frame at the connecting portion is not necessary, and labor and time at the site can be saved. .

Further, FIG. 15 shows a structure in which the end of the spar is fixed to the retaining wall 2 by a tension P of the PC steel rod and rigidly connected to the retaining wall 2 which is a supporting part of the spar.
A PC steel rod 39 is disposed in advance on the retaining wall 2 and its tip is fixed in the retaining wall. After the installation of the girder 3, the extension PC steel bar 39e is connected by the coupler 39c and extended to the top end of the girder 3, the composite structure connecting part 36 at the center of the girder 3 is completed, and the divided girder is integrated. After being completed as a simple girder, the joint mortar 39m was filled between the SPC girder 3 and the retaining wall 2 and hardened, and then the PC steel bar 39 was tension-fixed on the upper surface of the girder end to fix the end of the girder. Rigidly attached to the retaining wall 2.
In addition, although illustration is abbreviate | omitted, the rigid fastening method is not restricted to this, For example, the PC steel rod 39e is penetrated horizontally between the earth retaining wall 2 and the end part of the girder 3, and the tension is fixed similarly. Then, it may be rigidly connected.

FIG. 16A shows a moment diagram when the SPC girder is placed on the temporary cradle. Since the divided SPC girders 3a and 3b before the connection are simple girders with the span length supported at both ends by the retaining wall 2 and the temporary support 15 and L / 2, the moment at the support point is zero. There is a maximum moment at the center of each girder where the span length is L / 2. When this is connected and integrated at the connecting portion at the center of the girder to complete the composite structure connecting portion, this girder becomes a simple girder whose end is supported by both retaining wall retaining walls 2a and 2b and the span length is L. Therefore, the moment distribution is as shown in FIG.
Further, as shown in FIG. 15, when the end of the spar is tension-fixed to the retaining wall 2 by the tension steel material 39 by the tension steel P, a negative moment acts on the end of the spar, so that FIG. As shown in the moment diagram, a part of the bending moment due to the load acting on the SPC girder whose span length is L is borne at the end of the girder, and the bending stress acting on the composite connecting portion 36 at the center of the girder is It will be reduced, and the digit height can be lowered.

An example of a method for securing a work zone W for passing the SPC girder over the road without completely blocking the road is shown below. The example shown here is an example of a road with two lanes above and below.
As shown in FIG. 17 (1), the traffic zone T is secured by using one of the two lanes of the upper and lower lines for up and down traffic, and approximately half or more of the roads on the opposite two lanes are closed. This is suitable when the SPC girder is passed from the retaining wall 2 to a temporary cradle installed near the center line.
In the example shown in FIG. 17 (2), the roadside belt side of the upper and lower lines is used as a traffic belt T for traffic, and the work belt W around the central line is secured by blocking the traffic on the central line side. The work band W suitable for the work of forming the composite structure connecting portion 36 by spanning the SPC girders from the retaining walls on both sides is formed.

FIG. 18 (1) shows a cross section of the installed girder 3 in the longitudinal direction of the road. The girder 3 is installed between the retaining walls 2 in parallel with a predetermined interval. A precast concrete floor slab 41 is stretched between them, and the ground cover 45 is formed integrally with the SPC girder 3 on the left and right side girders 3, and faces the roads on both ends of the artificial ground. The parts of the parts to be made are made of precast as much as possible, so that the field work can be omitted, the structure facing the road can be quickly formed just by assembling at the field, the subsequent work, For example, a concrete floor slab is formed by placing the top concrete 42, and then finishing and paving work, as well as railing installation work, etc. are performed on the artificial ground structure formed by releasing road traffic restrictions. Can shorten the work period It is possible to achieve.
18 (2) is a cross-sectional view of the position of the retaining wall 2, and FIG. 18 (3) is a cross-sectional view of a portion where the upper edge of the girder 3 is enlarged to form an enlarged portion (flick) 3H. 18 (4) is provided with precast cross beams 3P between the parallel beams 3 so that a structure facing the road can be quickly formed by the tension steel material 37 penetrating them. After the cross beam 3P is completed, various operations can be performed on the structure of the artificial ground 10 formed by releasing the road traffic regulation.

1 Semi-underground road 10 Artificial ground 15 Temporary cradle 2, 2a, 2b Earth retaining wall 3, 3a, 3b SPC girder 3E Base 3H Enlarged part (Fushikashi)
3U _1-3 Girder Unit 3M Girder Unit Connection 3J Lower Edge Extension 3P Cross Girder 31 Steel Frame 32 Connection Steel 33 Concrete, Non-shrink Mortar 34, 34a Connection PC Steel 34S Connection PC Steel Sheath 35 Pretension Method PC Steel 35a Post-tension PC steel 36 Composite structure connecting part (connecting part)
37 Lateral tension steel material 39 Girder end fixing tension steel material 39c Coupler 39e Extended tension steel material 39m Joint mortar
4 Floor slab 45 Ground cover 5 Extension fixing part G Ground T Traffic zone W Work zone

Claims (9)

This is a method of constructing artificial ground on a semi-underground road with retaining walls on both sides. Precast concrete PC girders (SPC girders) with steel frames on the compression side are distances between retaining walls (L) The cross section is designed as a simple girder having a span length as a span girder, and this section is an SPC girder having a girder length less than half the span length (L / 2), and a connecting steel frame projecting from the front end surface to the front end portion; Temporary cradle with a sheath for connecting PC steel, securing at least one lane in the upper and lower lanes, securing a work zone as the other traffic stop, and installing the SPC girder from one retaining wall to the center of the road Bridge between the doors, change the working lane by switching the traffic lane, change the work zone, and place the SPC girder from the other retaining wall to the temporary receiving stand so as to face each other, and the connecting steel frame protruding from the tip of the SPC girder For connecting together and for connecting PC steel materials Connected PC steel material is inserted and disposed in the base, and concrete is placed between the SPC girders facing each other and hardened, and the connected PC steel material is tension-fixed and prestressed to provide the connection steel frame and the connected PC steel material. A semi-underground type characterized in that after the SPC simple girder between the retaining walls with the span length L is formed by forming the composite structure connecting portion including the SPC girder, the temporary support is removed. How to build artificial ground on the road. In Claim 1, after forming the said composite connection part and integrating a SPC girder, the both ends of a SPC simple girder are rigidly connected to the retaining wall with the tension | tensile_strength by PC steel material, and removes a temporary support stand after that. A method of constructing artificial ground on a semi-underground road characterized by In Claim 1 or 2, securing a traffic zone of at least one upper and lower lane, securing a work zone by blocking over approximately half or more of the opposite road, and spanning the SPC girder to form a composite structure connecting portion A method of constructing artificial ground on a semi-underground road characterized by 3. The vehicle according to claim 1 or 2, wherein the SPC girder is routed in a state in which traffic on one side opposite two lanes is secured and approximately half or more of the opposite road is closed and a work zone is secured, and then one side lane on both sides of the road. A method of constructing artificial ground on a semi-underground road characterized by securing each traffic zone and blocking the center of the road to secure a work zone to form a composite structure connection part. An SPC girder in which steel frame steel material is arranged on the compression side of the girder cross section for constructing artificial ground on the upper part of the semi-underground road with retaining walls on both sides, and the girder cross section is the span length between the retaining walls (L) is designed as a simple girder, and the girder length is less than one half of the span length (L), which is joined by a composite structure connecting part. The composite structure connecting part is an SPC girder. It is connected with a connecting steel frame that protrudes from the tip of the steel, and the connecting steel is embedded in the tip of the SPC girder and protrudes from the tip, and the connecting PC steel material is arranged across the connecting part. SPC girder characterized by being tensioned. 6. The SPC girder according to claim 5, wherein the connected PC steel material disposed in the composite structure connecting portion is disposed in a section of 1/3 or less of the span length (L). The SPC girder according to claim 5 or 6, wherein an enlarged portion (fluff) having a larger girder height is provided in the composite structure connecting portion. The SPC girder according to any one of claims 5 to 7 is erected on the retaining wall on both sides of the semi-underground road, and the end of the girder is tension-fixed to the retaining wall by the PC steel material and rigidly connected to the retaining wall. SPC digit characterized by 9. The SPC girder according to claim 5, wherein the girder height span ratio is 1/22 to 1/30.