Low-cost precast beam yard structure applicable within subgrade, construction method and beam transportation method

Abstract

The present invention discloses a low-cost precast beam yard structure applicable within a subgrade, which includes a steel bar processing area, a steel bar skeleton binding area, a beam manufacturing area, a beam storage area, and a hoisting area that are connected in sequence from the rear to the front. A cutting is excavated in the hoisting area, and the bottom surface of the cutting is lower at the front and higher at the rear with a slope; a beam transporting outlet is provided at the front end of the cutting, and the beam transporting height of the beam yard is reduced by the cutting, and the beam transporting distance between the beam yard and the bridge erection area is shortened under the same beam transporting slope; the present invention also discloses a corresponding construction method and a beam transporting method. The present invention can shorten the beam transporting distance between the beam yard and the bridge erection area under the same beam transporting slope, so as to shorten the beam transporting distance as much as possible within a limited space on the premise of ensuring that the beam transporting slope meets the design requirements, expand the operation area of the beam yard, improve the site utilization rate, obtain a larger beam yard operation area under the same site size, improve the efficiency of beam yard operation, and reduce the construction cost of the beam yard.

Description

Technical Field

[0001] The present invention relates to the technical field of highway bridge engineering construction, in particular to precast beam yard technology and beam transportation technology. Background Art

[0002] In modern highway construction, the location of the precast beam yard has a great impact on project costs and construction periods. Selecting a site for the precast beam yard far from the bridge erection area has the advantage of a larger selection space, but also has high land acquisition costs. During the bridge construction process, it is often necessary to transport precast beams from a distant precast beam yard to the bridge location, which often requires secondary transfer of the precast beams, increasing construction costs and reducing construction efficiency.

[0003] If a suitable location within the roadbed within the bridge construction red line is selected to set up the beam yard, the cost of additional land acquisition is saved, land occupation is saved, and the beam transportation distance is also greatly shortened, avoiding secondary transfer of the precast beams, which can significantly reduce construction costs and improve construction efficiency as a whole.

[0004] When setting up a beam yard within the roadbed within the bridge construction red line, due to site restrictions, the precast beam yard is set as a long strip shape, with the direction of transporting the precast beams to the bridge erection area as the forward direction. The existing precast beam yard includes a steel bar processing area, a steel bar skeleton binding area, a beam manufacturing area, and a beam storage area from the back to the front. A beam transportation channel is set between the beam storage area and the bridge erection area. When the height difference between the precast beam yard and the bridge erection area is larger, the length of the beam transportation channel relative to the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, and the beam storage area needs to be longer to meet the slope requirements for beam transportation (in the prior art, due to safety production requirements, the slope of beam transportation must be restricted).

[0005] Due to limited overall space, the longer the length of the beam transportation channel relative to the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, and the beam storage area, the shorter the lengths of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, and the beam storage area, which compresses the working area of the beam yard.

[0006] The technical personnel of our unit first tested excavating the precast beam yard as a whole and reducing the height of the precast beam yard to narrow the height difference between the precast beam yard and the bridge erection area, thereby shortening the beam transportation channel and increasing the working area of the precast beam yard. However, this method has too much earthwork excavation volume, which greatly increases the project cost on the one hand and prolongs the construction period on the other hand. Summary of the Invention

[0007] The purpose of the present invention is to provide a low-cost precast beam yard structure applicable within the roadbed with a small amount of earthwork excavation and a relatively large effective working area of the precast beam yard.

[0008] To achieve the above object, the present invention provides a low-cost precast beam yard structure applicable within a subgrade. With the direction of transporting precast beams to the bridge erection area as the forward direction, the precast beam yard includes a steel bar processing area, a steel bar skeleton binding area, a beam manufacturing area, and a beam storage area that are connected in sequence from the rear to the front. The total area of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, and the beam storage area is the working area of the beam yard;

[0009] It also includes a hoisting area. The hoisting area is located in front of the beam storage area and is connected to the beam storage area. A cutting is excavated in the hoisting area, and the bottom surface of the cutting is low in the front and high in the rear with a slope; a beam transportation outlet is provided at the front end of the cutting, and the beam transportation outlet is directly connected to the bridge erection area or is connected to the bridge erection area through a beam transportation channel. By means of the cutting, the beam outlet height of the beam yard is reduced, and the beam transportation distance between the beam yard and the bridge erection area is shortened under the same beam transportation slope;

[0010] Installation grooves for passing gantry cranes are excavated on both sides of the beam yard along the front-rear direction. The bottom of the installation groove is the foundation of the gantry crane. Gantry crane tracks are laid along the front-rear direction on the foundation of the gantry crane, and gantry cranes are provided on the gantry crane tracks;

[0011] The gantry crane includes a steel bar gantry crane and a precast beam gantry crane; the steel bar gantry crane is used to move and lift materials between the steel bar processing area, the steel bar skeleton binding area, and the beam manufacturing area; the precast beam gantry crane is used to move and lift materials between the beam manufacturing area, the beam storage area, and the hoisting area.

[0012] Water retaining structures are respectively provided on the left side, right side, and rear side of the cutting. The water retaining structures on the left side, right side, and rear side of the cutting are connected to each other and enclose the cutting;

[0013] The water retaining structure is a concave water retaining groove or a convex water retaining ridge.

[0014] There is at least one steel bar gantry crane, and there are at least two precast beam gantry cranes. The number of precast beam gantry cranes is more than the number of steel bar gantry cranes.

[0015] The water retaining structure is located inside the gantry crane track, and the distance between the cutting and the gantry crane track is greater than or equal to 3 meters.

[0016] The heights of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, the beam storage area, and the hoisting area are sequentially reduced to form a stepped layout; pedestrian steps for staff to walk are provided between the gantry crane track and the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, the beam storage area, and the hoisting area, and the pedestrian steps are set with a lower front and a higher rear.

[0017] A shotcrete layer is provided on the side wall of the cutting, and the bottom surface of the cutting is low in the front and high in the rear with a slope.

[0018] The present invention also discloses a construction method for the above low-cost precast beam yard structure applicable within a subgrade, which is carried out according to the following steps:

[0019] The first step is the construction steps for each area; the steel bar processing area, the steel bar framework binding area, the beam manufacturing area, the beam storage area, and the hoisting area are all working areas, and this step conducts construction on each working area separately;

[0020] For each working area, first excavate to a predetermined height, and level the surfaces of the steel bar processing area, the steel bar framework binding area, the beam manufacturing area, and the beam storage area respectively; the excavation of the hoisting area refers to the excavation of a cutting, and the bottom surface of the cutting is lower in the front and higher in the rear with a slope;

[0021] Construct gantry crane foundations on both sides of each working area and install gantry crane tracks, and install a steel bar gantry crane and a precast beam gantry crane on the gantry crane tracks; construct a front-low-and-rear-high pedestrian step on the inner side of the gantry crane tracks;

[0022] The second step is the reinforcement and waterproof construction steps for the hoisting area;

[0023] Conduct shotcreting with wire mesh operation on the side wall of the cutting to form a wire mesh shotcrete layer on the side wall of the cutting;

[0024] Construct a water retaining trough or a water retaining ridge on the rear side and the left and right sides of the cutting to form a waterproof structure.

[0025] The present invention also discloses a method for transporting precast beams of the above-mentioned low-cost precast beam yard structure applicable within the subgrade range. Reinforcements are processed in the steel bar processing area; steel bar frameworks are bound in the steel bar framework binding area; precast beams are manufactured in the beam manufacturing area using steel bar frameworks and concrete; precast beams are stored in the beam storage area;

[0026] When transporting the precast beam out, drive the transport vehicle into the cutting from the beam transport exit. When driving into the cutting, the head of the transport vehicle is forward and it reverses into the cutting from the front to the back;

[0027] Use the precast beam gantry crane to lift the precast beam stored in the beam storage area onto the transport vehicle within the cutting, and the transport vehicle drives forward out of the beam transport exit and transports the precast beam to the bridge erection area.

[0028] The present invention has the following advantages:

[0029] Adopting the beam yard structure of the present invention can shorten the beam transport distance between the beam yard and the bridge erection area under the same beam transport slope, so as to minimize the beam transport distance within a limited space on the premise of ensuring that the beam transport slope meets the design requirements, expand the working area of the beam yard, improve the site utilization rate, obtain a larger beam yard working area under the same site size, improve the efficiency of beam yard operations, and reduce the construction cost of the beam yard.

[0030] Existing beam yards also need to lift precast beams onto transport vehicles. The hoisting area in the present invention occupies the position where transport vehicles were originally parked. Therefore, the setting of the hoisting area will not increase the site occupation area compared with the past.

[0031] The installation of the steel bar gantry crane and the precast beam gantry crane enables the simultaneous lifting of steel bars and precast beams, improving the lifting efficiency compared to using only one gantry crane.

[0032] The installation of the water retaining structure can prevent rainwater near the cutting from flowing into the cutting, thus damaging the working environment inside the cutting and affecting the normal beam extraction operation.

[0033] In practice, the lifting tasks related to precast beams are more important than those related to steel bars. In the present invention, the number of precast beam gantry cranes is more than that of steel bar gantry cranes, which can make the lifting operations related to steel bars and the lifting work related to precast beams more matching, make the working efficiency of each part more balanced, eliminate bottlenecks, and improve the overall working efficiency.

[0034] When working, the load on the gantry crane is large. The distance between the cutting and the gantry crane track is greater than or equal to 3 meters, which can enable the gantry crane foundation to have sufficient ability to resist shear stress and prevent the foundation of the gantry crane from being damaged during work.

[0035] The heights of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, the beam storage area, and the hoisting area decrease in sequence to form a stepped layout. The advantages of this are: first, compared with overall excavation, the earthwork excavation workload is greatly reduced; second, the cutting depth is reduced, and the difficulty of hoisting precast beams into the cutting is lowered. The setting of the pedestrian steps facilitates the passage of staff between various areas of the precast beam yard. The shotcrete layer can prevent the soil on the side wall of the cutting from collapsing and ensure the safety of beam transportation.

[0036] Through the construction method of the present invention, the construction of the low-cost precast beam yard structure applicable within the roadbed can be completed quickly. By using the low-cost precast beam yard structure applicable within the roadbed and the corresponding beam transportation method of the present invention, precast beams can be efficiently transported to the bridge erection area. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic structural diagram of the present invention;

[0038] Figure 2 is Figure 1 an enlarged view of part A in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Figure 1 and Figure 2 the direction indicated by the arrow in

[0040] As shown in Figure 1 and Figure 2As shown in the figure, the present invention provides a low-cost precast beam yard structure applicable within the subgrade. With the transporting direction of the precast beam to the bridge erection area as the forward direction, the precast beam yard includes a steel bar processing area 1, a steel bar skeleton binding area 2, a beam manufacturing area 3, and a beam storage area 4 that are connected in sequence from the rear to the front. The total area of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, and the beam storage area 4 is the working area of the beam yard;

[0041] It further includes a hoisting area 5. The hoisting area 5 is located in front of the beam storage area 4 and is connected to the beam storage area 4. A cutting excavation 6 is dug in the hoisting area 5. The bottom surface of the cutting excavation 6 is lower at the front and higher at the rear with a slope. A beam transporting exit 7 is provided at the front end of the cutting excavation 6. The beam transporting exit 7 is directly connected to the bridge erection area or is connected to the bridge erection area through a beam transporting passage. By means of the cutting excavation 6, the beam discharging height of the beam yard is reduced, and the beam transporting distance between the beam yard and the bridge erection area is shortened under the same beam transporting slope;

[0042] Installation grooves 8 for passing gantry cranes are dug on both sides of the beam yard along the front-rear direction. The bottom of the installation groove 8 is the foundation 9 of the gantry crane. A gantry crane track 10 is laid along the front-rear direction on the foundation 9 of the gantry crane, and a gantry crane is provided on the gantry crane track 10;

[0043] The gantry crane includes a steel bar gantry crane 11 and a precast beam gantry crane 12; the steel bar gantry crane 11 is used to move between the steel bar processing area 1, the steel bar skeleton binding area 2, and the beam manufacturing area 3 and hoist materials such as steel bars and steel bar skeletons; the precast beam gantry crane 12 is used to move between the beam manufacturing area 3, the beam storage area 4, and the hoisting area 5 and hoist materials such as precast beams.

[0044] Adopting the beam yard structure of the present invention can shorten the beam transporting distance between the beam yard and the bridge erection area under the same beam transporting slope. Thus, on the premise of ensuring that the beam transporting slope meets the design requirements, the beam transporting distance can be shortened as much as possible within a limited space, the working area of the beam yard can be expanded, the site utilization rate can be improved, a larger working area of the beam yard can be obtained under the same site size, and the working efficiency of the beam yard can be improved.

[0045] In the existing beam yard, the precast beam also needs to be hoisted onto the transport vehicle. The hoisting area 5 in the present invention occupies the position where the transport vehicle was originally parked. Therefore, the setting of the hoisting area 5 will not increase the site occupation area compared with the past.

[0046] The setting of the steel bar gantry crane 11 and the precast beam gantry crane 12 can hoist steel bars and precast beams simultaneously, improving the hoisting efficiency compared with only using one gantry crane.

[0047] Water retaining structures 13 are respectively provided on the left side, right side, and rear side of the cutting excavation 6. The water retaining structures 13 on the left side, right side, and rear side of the cutting excavation 6 are connected to each other and enclose the cutting excavation 6;

[0048] The water retaining structure 13 is a concave water retaining groove or a convex water retaining ridge.

[0049] The provision of the water retaining structure 13 can prevent rainwater near the cutting 6 from flowing into the cutting 6, thus damaging the working environment inside the cutting 6 and affecting the normal beam launching operation.

[0050] There is at least one steel bar gantry crane 11, and there are at least two precast beam gantry cranes 12. The number of precast beam gantry cranes 12 is more than that of the steel bar gantry cranes 11.

[0051] In practice, the lifting tasks related to precast beams are heavier than those related to steel bars. In the present invention, the number of precast beam gantry cranes 12 is more than that of the steel bar gantry cranes 11, which can make the lifting operations related to steel bars and the lifting work related to precast beams more matching, make the working efficiency of each part more balanced, eliminate bottlenecks, and improve the overall working efficiency.

[0052] The water retaining structure 13 is located inside the gantry crane track 10, and the distance between the cutting 6 and the gantry crane track 10 is greater than or equal to 3 meters.

[0053] During operation, the load on the gantry crane is large. The distance between the cutting 6 and the gantry crane track 10 being greater than or equal to 3 meters can enable the gantry crane foundation 9 to have sufficient ability to resist shear stress and prevent the gantry crane foundation 9 from being damaged during operation.

[0054] The heights of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, the beam storage area 4, and the hoisting area 5 decrease in sequence to form a stepped layout; there is a pedestrian step 14 for staff to walk between the gantry crane track 10 and the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, the beam storage area 4, and the hoisting area 5, and the pedestrian step 14 is set with the front lower and the rear higher.

[0055] The heights of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, the beam storage area 4, and the hoisting area 5 decrease in sequence to form a stepped layout. The advantages of this are: firstly, compared with overall excavation, the earthwork excavation workload is greatly reduced; secondly, the depth of the cutting 6 is reduced, and the difficulty of hoisting precast beams into the cutting 6 is lowered.

[0056] The provision of the pedestrian step 14 facilitates the passage of staff between the various areas of the precast beam yard.

[0057] The side wall of the cutting 6 is provided with a shotcrete layer 15, the bottom surface of the cutting 6 is inclined with the front lower and the rear higher, and the slope of the bottom surface of the cutting 6 meets the slope requirements for the operation of the beam transport vehicle.

[0058] The shotcrete layer 15 can prevent the soil body on the side wall of the cutting 6 from collapsing and ensure the safety of beam transportation.

[0059] The present invention also discloses a construction method for the above low-cost precast beam yard structure applicable within the roadbed range, which is carried out according to the following steps:

[0060] The first step is the construction steps for each area; the steel bar processing area 1, the steel bar skeleton binding area 2, the beam fabrication area 3, the beam storage area 4, and the hoisting area 5 are all working areas, and in this step, construction is carried out for each working area respectively;

[0061] For each working area, first excavate to the predetermined height and level the surfaces of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam fabrication area 3, and the beam storage area 4 respectively; the excavation of the hoisting area 5 refers to the excavation of the cutting 6, and the bottom surface of the cutting 6 is lower in the front and higher in the rear with a slope;

[0062] Construct the gantry crane foundations 9 on both sides of each working area and install the gantry crane tracks 10, and install the steel bar gantry crane 11 and the precast beam gantry crane 12 on the gantry crane tracks 10; construct the front-low and rear-high pedestrian steps 14 inside the gantry crane tracks 10;

[0063] The second step is the reinforcement and waterproof construction steps for the hoisting area 5;

[0064] Carry out the operation of hanging the mesh and spraying concrete on the side wall of the cutting 6 to form a shotcrete layer 15 on the side wall of the cutting 6;

[0065] Construct a water retaining trough or a water retaining ridge on the rear side and the left and right sides of the cutting 6 to form a waterproof structure.

[0066] The present invention also discloses a method for transporting precast beams of the above-mentioned low-cost precast beam yard structure applicable within the roadbed range. Reinforcement bars are processed in the steel bar processing area 1; the steel bar skeleton is bound in the steel bar skeleton binding area 2; precast beams are made using the steel bar skeleton and concrete in the beam fabrication area 3; precast beams are stored in the beam storage area 4; it is characterized in that:

[0067] When transporting the precast beam out, drive the transport vehicle from the beam transport exit 7 into the cutting 6. When driving into the cutting 6, the head of the transport vehicle is forward and it reverses into the cutting 6 from the front to the back; in this way, the transport vehicle does not need to turn around after receiving the precast beam and can drive forward directly.

[0068] Use the precast beam gantry crane 12 to hoist the precast beam stored in the beam storage area 4 onto the transport vehicle in the cutting 6, and the transport vehicle drives forward out of the beam transport exit 7 and transports the precast beam to the bridge erection area.

[0069] The present invention has carried out engineering practice experiments.

[0070] Hongnongjian Extra-large Bridge, a control project of the Sanmenxia to National Highway 310 Southward New Construction Project located in Lingbao City, Henan Province, the precast beam yard of its west approach bridge section is arranged within the roadbed range. The planned precast beam yard and the beam transport channel are both arranged on the roadbed in the direction away from the bridge of the abutment. The available roadbed range is limited. The total length of the precast beam yard and the beam transport channel is 800 meters, and the total height difference is 24.710 meters.

[0071] The precast beam yard is planned and designed according to the traditional layout method: the precast beam yard is planned to have four areas, namely, the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, and the beam storage area 4, with a length of 480 meters, a longitudinal slope of 15‰, and a height difference of 7.200 meters. Then the length of the beam transportation channel is 320 meters, the height difference is 17.462 meters, and the longitudinal slope is 54.6‰. This slope does not meet the requirement that the longitudinal slope of the precast beam transportation and erection line in the "Technical Specification for Highway Bridge and Culvert Construction" (JTG / T F50-2011) should not be greater than 30‰. If the longitudinal slope of the beam transportation channel is restricted within 30‰ according to the traditional precast beam yard layout method, it is necessary to shorten the total length of the four areas of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, and the beam storage area 4, and extend the length of the beam transportation channel. However, this will greatly reduce the working area of the operation area and reduce the operation throughput capacity of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, and the beam storage area 4.

[0072] After adopting the present invention, the precast beam yard is arranged with five areas, namely, the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, the beam storage area 4, and the hoisting area 5. The four areas of the steel bar processing area 1, the steel bar skeleton binding area 2, the beam manufacturing area 3, and the beam storage area 4 have a length of 480 meters, a longitudinal slope of 15‰, and a height difference of 7.200 meters. The length of the hoisting area 5 is 50 meters. At the junction of the beam storage area 4 and the hoisting area 5, the depth of the cut 6 is 7.960 meters. The total length of the hoisting area 5 and the beam transportation channel is 320 meters, and the height difference is 9.502 meters. The bottom road surface of the cut 6 in the hoisting area 5 is directly connected to the beam transportation channel and has the same slope. The calculated value of their longitudinal slope is 29.7‰, which meets the requirements.

[0073] Compared with the traditional layout method, the layout method of the precast beam yard of the present invention occupies the area of part of the beam transportation channel without increasing the floor area. At the same time, on the premise of not extending the beam transportation channel, the slope of the beam transportation channel meets the requirement of not being greater than 30‰, saving about 500,000 yuan in the total project construction cost, and having obvious economic benefits.

[0074] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the present invention can still be modified or equivalently replaced, and any modification or partial replacement without departing from the spirit and scope of the present invention should be covered by the scope of the claims of the present invention.

Claims

1. A low-cost precast beam yard structure applicable within a subgrade range, with the forward direction being the direction for transporting precast beams to the bridge erection area. The precast beam yard includes a steel bar processing area, a steel bar skeleton binding area, a beam manufacturing area, and a beam storage area that are connected in sequence from the rear to the front. The total area of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, and the beam storage area is the working area of the beam yard; It is characterized in that: It also includes a hoisting area. The hoisting area is located in front of the beam storage area and is connected to the beam storage area. A cutting slope is excavated in the hoisting area, and the bottom surface of the cutting slope is low in the front and high in the rear with a slope. A beam transportation exit is provided at the front end of the cutting slope, and the beam transportation exit is directly connected to the bridge erection area or is connected to the bridge erection area through a beam transportation channel. By means of the cutting slope, the beam discharging height of the beam yard is reduced, and the beam transportation distance between the beam yard and the bridge erection area is shortened under the same beam transportation slope; Installation grooves for passing gantry cranes are excavated on both sides of the beam yard along the front-rear direction. The bottom of the installation groove is the foundation of the gantry crane. Gantry crane tracks are laid along the front-rear direction on the foundation of the gantry crane, and gantry cranes are provided on the gantry crane tracks; The gantry crane includes a steel bar gantry crane and a precast beam gantry crane; the steel bar gantry crane is used to move and hoist materials between the steel bar processing area, the steel bar skeleton binding area, and the beam manufacturing area; the precast beam gantry crane is used to move and hoist materials between the beam manufacturing area, the beam storage area, and the hoisting area; Water retaining structures are respectively provided on the left side, the right side, and the rear side of the cutting slope. The water retaining structures on the left side, the right side, and the rear side of the cutting slope are connected to each other and enclose the cutting slope; The water retaining structure is a concave water retaining groove or a convex water retaining ridge; There is at least one steel bar gantry crane, and there are at least two precast beam gantry cranes. The number of precast beam gantry cranes is more than the number of steel bar gantry cranes.

2. The low-cost precast beam yard structure applicable within the roadbed range according to claim 1, wherein: The water retaining structure is located inside the gantry crane track, and the distance between the cutting slope and the gantry crane track is greater than or equal to 3 meters.

3. The low-cost precast beam yard structure applicable within the subgrade range according to claim 1 or 2, characterized in that: The heights of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, the beam storage area, and the hoisting area are successively reduced to form a stepped layout; pedestrian steps for staff to walk are provided between the gantry crane track and the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, the beam storage area, and the hoisting area, and the pedestrian steps are set low in the front and high in the rear.

4. The low-cost precast beam yard structure applicable within the roadbed range according to claim 1 or 2, characterized in that: A shotcrete layer with mesh is provided on the side wall of the cutting slope, and the bottom surface of the cutting slope is low in the front and high in the rear with a slope.

5. The construction method of the low-cost precast beam yard structure applicable within the subgrade range described in claim 4, characterized in that It is carried out according to the following steps: The first step is the construction steps for each area; the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, the beam storage area, and the hoisting area are all working areas, and this step is to carry out construction on each working area separately; For each working area, first excavate to the predetermined height, and level the surfaces of the steel bar processing area, the steel bar skeleton binding area, the beam manufacturing area, and the beam storage area respectively; the excavation of the hoisting area refers to excavating the cutting slope, and the bottom surface of the cutting slope is low in the front and high in the rear with a slope; Construct the gantry crane foundation on both sides of each working area and install the gantry crane track, install the steel bar gantry crane and the precast beam gantry crane on the gantry crane track; construct the pedestrian steps that are low in the front and high in the rear on the inner side of the gantry crane track; The second step is the reinforcement and waterproof construction steps for the hoisting area; Carry out the operation of hanging mesh and spraying concrete on the side wall of the cutting slope to form a shotcrete layer with mesh on the side wall of the cutting slope; Construct a water retaining groove or a water retaining ridge on the rear side and the left and right sides of the cutting slope to form a waterproof structure.

6. The beam transporting method for the low-cost precast beam yard structure applicable within the subgrade scope described in claim 4, wherein steel bars are processed in the steel bar processing area; steel bar skeletons are tied in the steel bar skeleton tying area; precast beams are fabricated in the beam fabrication area using the steel bar skeletons and concrete; precast beams are stored in the beam storage area; and it is characterized in that: When transporting the precast beam out, the transport vehicle drives into the cutting from the beam transport exit. When driving into the cutting, the head of the transport vehicle faces forward and it reverses into the cutting from the front to the back. The precast beam gantry crane is used to lift the precast beam stored in the beam storage area onto the transport vehicle within the cutting. The transport vehicle drives forward out of the beam transport exit and transports the precast beam to the bridge erection area.

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