An assembled anti-collision guardrail, construction method and bridge

Abstract

The application relates to the technical field of bridge construction, and provides a fabricated anti-collision guardrail, a construction method and a bridge, wherein the fabricated anti-collision guardrail comprises a fabricated shell and a steel reinforcement cage; the fabricated shell comprises an inner baffle and an outer baffle; the inner baffle and the outer baffle are arranged side by side and at intervals; the steel reinforcement cage is arranged between the outer baffle and the inner baffle; a concrete structure is filled between the outer baffle and the inner baffle; the bottom of the outer baffle can be connected to an edge main beam; and the bottom of the inner baffle can be connected to a bridge deck slab steel reinforcement. The fabricated anti-collision guardrail can solve the problems of complex construction process, large operation amount, long construction time, large labor input and large environmental impact of the existing anti-collision guardrail.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, and in particular to a prefabricated crash barrier, construction method, and bridge. Background Technology

[0002] In the field of highway bridges, crash barriers are installed on the side main beams of the bridge superstructure. Their purpose is to prevent out-of-control vehicles from going off the bridge, serving to prevent vehicles from breaking through, passing under, or overturning the bridge, and also enhancing the aesthetics of the bridge structure. Crash barriers are generally made of reinforced concrete, with a width of approximately 0.5m and a height of approximately 1m. The barrier itself weighs about 1.5 tons per meter. For bridges with a common span of 30m to 35m, the weight of the crash barriers resting on the side main beams alone can reach 45 to 52.5 tons, equivalent to the side main beams bearing the weight of an additional fully loaded six-axle truck compared to the central main beams.

[0003] In terms of design philosophy, the current design concept of crash barriers treats them as an auxiliary structure of bridges, only considering vehicle collision protection and decorative functions, without considering the improvement of the load-bearing capacity of the bridge structure. The crash barriers are applied to the bridge as an external load. In order to balance safety, bridge design has to invest more in material consumption, resulting in problems such as large concrete consumption for concrete bridges and high steel consumption for steel structure bridges, which is inconsistent with the low-carbon concept.

[0004] During construction, traditional reinforced concrete crash barriers require complex procedures on-site, including formwork erection, reinforcement binding, concrete pouring, concrete vibration, concrete curing, and formwork removal. This results in a large workload, high consumption of scaffolding and formwork, and a long construction period. The reinforcement binding process on traditional crash barrier construction is time-consuming and labor-intensive, requiring a significant workforce. This labor-intensive structure, materials, and processes are ill-suited to the demands of intelligent and rapid construction. Furthermore, scaffolding erection negatively impacts traffic flow and the surrounding environment. The scaffolding erection itself is also constrained by the surrounding environment, making construction difficult in harsh conditions such as canyons or mountainous terrain.

[0005] In summary, traditional bridge crash barriers are heavy, which is detrimental to the stress on the bridge and results in a high amount of main beam material used; moreover, they have long construction cycles, significant environmental impact, and low levels of prefabrication. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of complex construction procedures, large workload, long construction time, large labor input, and significant environmental impact of existing crash barriers, and to provide a prefabricated crash barrier, construction method, and bridge.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A prefabricated crash barrier includes a prefabricated outer shell and a reinforcing cage; the prefabricated outer shell includes an inner baffle and an outer baffle; the inner baffle and the outer baffle are arranged side by side and spaced apart; the reinforcing cage is disposed between the outer baffle and the inner baffle; the space between the outer baffle and the inner baffle is filled with a concrete structure; the bottom of the outer baffle can be connected to the side main beam; the bottom of the inner baffle can be connected to the bridge deck reinforcement.

[0009] The specific shape, size, and spacing of the outer and inner baffles shall be designed according to actual needs and crash barrier design specifications. The outer and inner baffles may be made of various materials with good toughness and strong impact resistance, such as steel plates or high-strength and high-toughness concrete slabs. The outer and inner baffles should preferably be prefabricated in the factory.

[0010] The connection between the bottom of the outer baffle and the side main beam shall refer to the existing connection methods, such as welding or threaded connection; the specific connection structure between the bottom of the outer baffle and the side main beam shall depend on the connection method adopted and the structure of the side main beam; the connection between the inner baffle and the bridge deck reinforcement shall refer to the existing connection methods, such as welding connection; if the inner baffle uses non-metallic components, a metal structure for welding the bridge deck reinforcement can be set on the inner baffle.

[0011] The grade of concrete used to fill the space between the outer and inner baffles is selected based on actual needs and the actual conditions of the construction site.

[0012] The length of the prefabricated shell and the steel cage is determined according to the actual conditions of the construction site, such as hoisting and transportation capabilities. If the length of a single prefabricated shell and steel cage is insufficient to meet the usage requirements, multiple prefabricated shells and corresponding steel cages can be set along the longitudinal direction of the bridge.

[0013] The steel cage is used as the internal load-bearing skeleton of the crash barrier. Its design is based on existing technology and the specific shape design of the prefabricated shell. It can adopt a combination of longitudinal steel bars and contour stirrups. The method of fixing the steel cage to the bridge can refer to existing technology, such as connecting the steel cage to the bridge deck steel bars.

[0014] This prefabricated crash barrier design includes an inner baffle and an outer baffle. The outer baffle can be connected to the side main beam, and the inner baffle can be connected to the bridge deck reinforcement. During construction, the reinforcement cage is connected to the bridge, the outer baffle is connected to the side main beam, and the inner baffle is connected to the bridge deck reinforcement. Then, the outer and inner baffles are directly used as the support structure for concrete pouring. Concrete is poured between the outer and inner baffles and cured to complete the construction of the crash barrier. This allows for rapid construction without scaffolding or formwork. On the one hand, it reduces the interference with bridge traffic and the surrounding environment during construction and effectively avoids the problems of high scaffolding and formwork consumption and great susceptibility to environmental impact caused by the traditional formwork and cast-in-place construction of crash barriers. On the other hand, it also reduces the complexity of the crash barrier construction process, thereby speeding up the construction and reducing the input of human resources.

[0015] Furthermore, the prefabricated shell and steel cage of this scheme can be further manufactured in a segmented prefabrication method in the factory, thereby reducing the weight and size of individual components of the prefabricated crash barrier, which facilitates transportation and hoisting, and is conducive to promoting the development of fully prefabricated bridge construction technology. At the same time, the use of factory prefabrication method is also beneficial to improving the processing accuracy of the prefabricated shell and steel cage, thereby improving the construction quality.

[0016] In a preferred embodiment of the present invention, the steel cage and the bridge deck steel bars are interconnected, as are the steel cage and the top of the side main beam.

[0017] The connection method between the reinforcing cage and the top of the side main beam depends on the actual situation. If the side main beam is an I-beam, the reinforcing cage can be directly welded to the top plate of the side main beam. If the side main beam is a concrete beam, metal connectors can be pre-embedded in the top of the side main beam and welded to the reinforcing cage, or the pre-embedded reinforcing bars in the side main beam can be welded to the reinforcing cage.

[0018] This design connects the crash barrier, bridge deck, and side main beams together using a steel cage, enabling them to work together to resist external loads in the vertical section.

[0019] As a preferred embodiment of the present invention, the reinforcing cage is a prefabricated component.

[0020] The steel cage in this design is a prefabricated component, which reduces the amount of steel bar binding work on the construction site, thereby reducing the input of human resources and speeding up the construction process.

[0021] As a preferred embodiment of the present invention, the reinforcing cage further includes longitudinal reinforcing bars; the longitudinal reinforcing bars are arranged along the length direction of the prefabricated shell; and the two ends of the longitudinal reinforcing bars extend out from the two ends of the prefabricated shell, respectively.

[0022] This solution enables two adjacent steel cages along the longitudinal direction of the bridge to be stably connected by overlapping longitudinal steel bars, thereby achieving the connection of two adjacent prefabricated crash barriers along the longitudinal direction of the bridge.

[0023] As a preferred embodiment of the present invention, a first edge-sealing angle steel is provided at the bottom of the inner baffle; the first edge-sealing angle steel is provided along the longitudinal direction of the bridge; a second edge-sealing angle steel is provided at both ends of the inner baffle along the longitudinal direction of the bridge and at both ends of the outer baffle along the longitudinal direction of the bridge; the second edge-sealing angle steel is provided along the corresponding edges of the inner baffle and the outer baffle.

[0024] The first edge-binding angle steel can be installed along the bottom of the inner baffle or not; similarly, the second edge-binding angle steel can be installed along the edges of both ends of the inner or outer baffle or not; the specific length and dimensions of the first and second edge-binding angle steels are determined according to actual needs.

[0025] This design incorporates a first edge-sealing angle steel at the bottom of the inner baffle and second edge-sealing angle steels at both ends of both the inner and outer baffles. This serves two purposes: firstly, it protects the corresponding edges of the inner and outer baffles from damage; secondly, it facilitates the welding of the inner baffle to the bridge deck reinforcement via the first edge-sealing angle steel, and the welding of the corresponding second edge-sealing angle steels to connect two adjacent inner or outer baffles along the longitudinal direction of the bridge. This design is particularly suitable for situations where the inner and outer baffles are not constructed of steel and are difficult to weld directly.

[0026] As a preferred embodiment of the present invention, the top of the assembled housing further includes a top clamp; the two ends of the top clamp are respectively connected to the inner baffle and the outer baffle; the top clamp is used to prevent the inner baffle and the outer baffle from moving away from or deflecting from each other.

[0027] The specific structure of the top clamp depends on actual needs, as long as it prevents the inner and outer baffles from moving away from or deflecting from each other. However, it should not obstruct the pouring of concrete into the prefabricated crash barrier. Methods such as distributing the top clamps at intervals along the longitudinal direction of the bridge or setting pouring holes on the clamps can be used to avoid obstructing the concrete pouring operation.

[0028] This solution ensures the stability of the inner and outer baffles during construction, especially during concrete pouring, preventing them from shifting or tilting to either side under external forces, such as concrete pressure, which could cause deformation of the prefabricated shell.

[0029] As a preferred embodiment of the present invention, the bottom of the outer baffle is provided with a Z-shaped bend; the Z-shaped bend is used to connect the outer edge of the side main beam.

[0030] The shape of the Z-shaped bend is based on sheet metal specifications. It includes a first right-angle bend connected to the bottom of the outer baffle and a second right-angle bend connected to the other end of the first right-angle bend and facing the opposite direction. The specific dimensions of the Z-shaped bend are determined according to the specific shape of the side main beam to which the outer baffle is to be connected. The Z-shaped bend can be connected to the outside of the side main beam in various ways, such as by welding or bolting.

[0031] This solution is a specific structure for connecting the outer side baffle and the outer edge of the side main beam. Since the common side main beams are I-shaped steel main beams and T-shaped concrete main beams, the Z-shaped bend can adapt to most existing side main beams. At the same time, compared with other shapes, such as L-shaped parts, the Z-shaped bend can also protect the outer edge of the side main beam after being connected to it, preventing rainwater from eroding the outer edge of the side main beam.

[0032] As a preferred embodiment of the present invention, the concrete structure between the outer baffle and the inner baffle is formed by pouring self-compacting concrete.

[0033] This scheme adopts a self-compacting concrete pouring concrete structure; self-compacting concrete can rely on its own weight and fluidity to uniformly and self-compact and fill the prefabricated shell without vibration, effectively reducing noise pollution to the environment and having environmentally friendly properties.

[0034] A construction method for a prefabricated crash barrier, applicable to a prefabricated crash barrier of the present invention, includes the following steps:

[0035] A. Place the steel reinforcement cage at the designated location on the bridge;

[0036] B. Connect the outer baffle to the outer edge of the main beam; connect the inner baffle to the bridge deck reinforcement; connect both ends of the clamp to the outer baffle and the inner baffle respectively;

[0037] C. Pour concrete between the outer baffle and the inner baffle.

[0038] In steps A and B, the entire steel cage of the bridge can be installed first, and then the outer and inner baffles can be installed. Alternatively, the steel cage and the corresponding outer and inner baffles can be installed in sections.

[0039] After step C, the concrete needs to be cured until the prefabricated crash barrier is formed.

[0040] The prefabricated crash barrier construction method of this scheme utilizes the outer and inner baffles as concrete pouring templates, thereby enabling rapid construction without scaffolding or formwork. This reduces interference with bridge traffic and the surrounding environment during construction, and avoids the problems of high consumption of scaffolding and formwork and significant environmental impact. It also speeds up construction and reduces the input of human resources.

[0041] A bridge includes several spans and a prefabricated crash barrier according to the present invention; the prefabricated crash barriers are distributed longitudinally along the bridge; two prefabricated crash barriers that are adjacent longitudinally along the bridge and located on the same span are fixedly connected; two prefabricated crash barriers that are adjacent longitudinally along the bridge but located on different spans are not fixedly connected.

[0042] The bridge in this solution adopts the prefabricated anti-collision guardrail of this invention, which can realize the construction of anti-collision guardrail without scaffolding or formwork, thereby reducing the interference to bridge traffic and the surrounding environment during construction. It also effectively avoids the problems of high consumption of scaffolding and formwork and great environmental impact caused by the traditional formwork and cast-in-place construction of anti-collision guardrail, and reduces the complexity of the construction process of anti-collision guardrail, thereby speeding up the construction and reducing the input of human resources.

[0043] Meanwhile, in this scheme, the prefabricated crash barriers along the longitudinal direction of the same bridge span are connected end to end, thus ensuring the continuity of the prefabricated crash barriers on the same bridge span. This allows the prefabricated crash barriers to participate in the load-bearing of the main beam, thereby enhancing the load-bearing capacity of the bridge and helping to reduce the weight and material consumption of the bridge.

[0044] As a preferred embodiment of the present invention, the width of the prefabricated outer shell along the transverse direction of the bridge is W; 650mm≤W≤850mm.

[0045] The width recommended in this scheme is wider than that of existing technologies. Although widening the prefabricated crash barrier increases its self-weight, thus adversely affecting the stress on the bridge structure, it also contributes more to the bending moment of inertia of the neutral axis of the main beam, providing greater bending load-bearing capacity and improving the bridge's load-bearing capacity. If we denote the stress effect on the main beam caused by the increased self-weight of the prefabricated crash barrier as ΔW, and the contribution of widening the prefabricated crash barrier to the load-bearing capacity of the main beam as ΔR, then the recommended crash barrier width in this scheme ensures that ΔR is greater than ΔW, thereby enabling this scheme to improve the bridge's load-bearing capacity.

[0046] Meanwhile, the width recommended in this scheme can also make the centroid of the prefabricated crash barrier and the centroid of the side main beam as close as possible to the same vertical plane, so that the prefabricated crash barrier and the side main beam form a superimposed structural system in the beam height direction. The prefabricated crash barrier can participate in the stress of the side main beam, further improving the overall load-bearing capacity of the bridge.

[0047] In summary, the width recommended in this scheme can improve the load-bearing capacity of the bridge, thereby facilitating the optimization of the bridge's structural dimensions, reducing the bridge's weight and material consumption, and demonstrating significant economic advantages.

[0048] The recommended width in this solution allows the prefabricated crash barrier to be positioned within the compression zone of the composite side beam system, thus fully leveraging the high compressive strength of concrete. This alleviates and transitions the compressive stress level of the side beam beneath the prefabricated crash barrier, while reducing the risk of cracking. It also provides good durability and reduces operating costs. Furthermore, compared to existing technologies, the wider width facilitates a stronger connection between the prefabricated crash barrier and the bridge, thereby minimizing the risk of slippage and separation between the prefabricated crash barrier and the side beam.

[0049] The recommended width in this plan also gives the prefabricated guardrail stronger resistance to vehicle impacts, reducing the risk of vehicles breaking through the guardrail and falling off the bridge in extreme situations.

[0050] As a preferred embodiment of the present invention, the top of the prefabricated crash barrier is provided with a dummy joint along the transverse direction of the bridge; the dummy joints are spaced apart along the longitudinal direction of the bridge; the depth of the dummy joint is Dg; the width of the dummy joint along the longitudinal direction of the bridge is Wg; 20mm≤Dg≤30mm; 2mm≤Wg≤4mm.

[0051] The specific parameters and quantity of dummy seams depend on the actual conditions of the construction site.

[0052] This solution sets a dummy joint at the top of the prefabricated crash barrier and recommends the width and depth of the dummy joint. This allows the prefabricated crash barrier to freely expand and contract under the influence of ambient temperature without weakening the cross-section of the prefabricated crash barrier or affecting the overlapping working mechanism of the prefabricated crash barrier and the side main beam.

[0053] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0054] 1. The prefabricated crash barrier in this scheme includes an inner baffle and an outer baffle. The outer baffle can be connected to the side main beam, and the inner baffle can be connected to the bridge deck reinforcement. During construction, the reinforcement cage is connected to the bridge, the outer baffle is connected to the side main beam, and the inner baffle is connected to the bridge deck reinforcement. Then, the outer baffle and the inner baffle are directly used as the support structure for concrete pouring. Concrete is poured between the outer baffle and the inner baffle and cured to complete the construction of the crash barrier.

[0055] This enables rapid construction without scaffolding or formwork, which reduces interference with bridge traffic and the surrounding environment during construction and effectively avoids the problems of high scaffolding and formwork consumption and significant environmental impact caused by traditional formwork and cast-in-place construction of crash barriers. On the other hand, it also reduces the complexity of crash barrier construction procedures, thereby accelerating construction speed and reducing the input of human resources.

[0056] If the prefabricated guardrail of this scheme is further manufactured in a segmented factory, the weight and size of the individual components of the prefabricated guardrail can be reduced, which will facilitate transportation and hoisting and promote the development of fully prefabricated bridge construction technology.

[0057] Furthermore, using factory prefabrication improves the processing precision of the prefabricated shell and reinforcing cage, thereby enhancing construction quality. This solution also allows for the use of self-compacting concrete for the concrete structure. Self-compacting concrete, relying on its own weight and fluidity, can uniformly and self-compact to fill the prefabricated shell without vibration, effectively reducing noise pollution and demonstrating environmental friendliness.

[0058] 2. The construction method of the prefabricated crash barrier in this plan uses the outer and inner baffles as concrete pouring templates, which enables rapid construction without scaffolding or formwork. This reduces the interference with bridge traffic and the surrounding environment during construction and avoids the problems of high consumption of scaffolding and formwork and great environmental impact. It also speeds up construction and reduces the input of human resources.

[0059] 3. The bridge in this solution adopts the prefabricated anti-collision guardrail of the present invention, which can realize the construction of the anti-collision guardrail without support or formwork, thereby reducing the interference to bridge traffic and the surrounding environment during construction, and effectively avoiding the problems of high consumption of support and formwork and great environmental impact caused by the traditional formwork and cast-in-place construction of anti-collision guardrails. It also reduces the complexity of the construction process of anti-collision guardrails, thereby speeding up the construction and reducing the input of human resources.

[0060] Meanwhile, in this scheme, the prefabricated crash barriers along the longitudinal direction of the same bridge span are connected end to end, thus ensuring the continuity of the prefabricated crash barriers on the same bridge span. This allows the prefabricated crash barriers to participate in the load-bearing of the main beam, thereby enhancing the load-bearing capacity of the bridge and helping to reduce the weight and material consumption of the bridge.

[0061] 4. This scheme also recommends a width of 650–850 mm for prefabricated crash barriers, which is wider than existing technologies. Although this increases its self-weight, thus adversely affecting the stress on the bridge structure, it also contributes more to the bending moment of inertia of the neutral axis of the main girder, providing greater bending capacity and improving the bridge's load-bearing capacity. If we denote the stress effect on the main girder caused by the increased self-weight of the prefabricated crash barriers as ΔW, and the contribution of the wider prefabricated crash barriers to the load-bearing capacity of the main girder as ΔR, then the recommended crash barrier width in this scheme can make ΔW…

[0062] R is greater than ΔW, thus enabling this scheme to improve the bridge's load-bearing capacity. Simultaneously, the recommended width ensures that the centroid of the prefabricated crash barrier and the centroid of the side main beam are located as close as possible in the same vertical plane. This allows the prefabricated crash barrier and the side main beam to form a composite structural system along the beam height, enabling the prefabricated crash barrier to participate in the load-bearing capacity of the side main beam, further enhancing the overall load-bearing capacity of the bridge.

[0063] In summary, the width recommended in this scheme can improve the load-bearing capacity of the bridge, thereby facilitating the optimization of the bridge's structural dimensions, reducing the bridge's weight and material consumption, and offering significant economic advantages. Furthermore, compared to existing technologies, widening the width also facilitates stronger connections between the prefabricated crash barriers and the bridge, thus minimizing the risk of slippage and separation between the prefabricated crash barriers and the main side beams.

[0064] The recommended width in this design allows the prefabricated crash barrier to be located in the compression zone of the composite side beam system, thus fully leveraging the high compressive strength of concrete, alleviating and transitioning the compressive stress level of the side beam below the prefabricated crash barrier, reducing the risk of cracking, providing good durability, and reducing operating costs.

[0065] The recommended width in this plan also gives the prefabricated guardrail stronger resistance to vehicle impacts, reducing the risk of vehicles breaking through the guardrail and falling off the bridge in extreme situations. Attached Figure Description

[0066] Figure 1 This is a cross-sectional schematic diagram of a prefabricated anti-collision guardrail connected to a concrete side main beam and with the steel reinforcement cage hidden, according to the present invention.

[0067] Figure 2 This is a cross-sectional schematic diagram of a prefabricated anti-collision guardrail connected to an I-beam side main beam and with the reinforcing cage hidden, according to the present invention.

[0068] Figure 3 This is a cross-sectional schematic diagram of the connection state between the prefabricated anti-collision guardrail and the concrete side main beam of the present invention.

[0069] Figure 4 This is a cross-sectional schematic diagram of the connection state between the assembled anti-collision guardrail and the I-beam side main beam of the present invention.

[0070] Figure 5 This is a schematic diagram of the welding connection between the first interface steel bar and the bridge deck steel bar;

[0071] Figure 6 This is a schematic diagram of the welding connection between the second interface steel bar and the pre-embedded steel bar of the side main beam;

[0072] Figure 7This is a side view of a prefabricated anti-collision guardrail of the present invention, viewed from the outer side panel to the inner side panel.

[0073] Figure 8 This is a side view of two assembled anti-collision guardrails of the present invention connected together;

[0074] Figure 9 This is a side view schematic diagram of a bridge according to the present invention;

[0075] Figure 10 This is a magnified view of a section of the fracture.

[0076] Figure 11 yes Figure 9 A magnified view of a portion of point I;

[0077] Figure 12 This is a schematic cross-sectional view of the bridge used as a case study in Example 2;

[0078] Figure 13 This is a side view schematic diagram of the bridge used as a case study in Example 2;

[0079] Icons: 1-Prefabricated shell; 2-Reinforcing cage; 3-Concrete structure; 4-Bridge span; 5-Bridge deck; 51-Bridge deck reinforcement; 6-Side main beam; 61-Side main beam top plate; 62-Side main beam embedded reinforcement; 101-Inner baffle; 102-Outer baffle; 103-First edge angle steel; 104-Second edge angle steel; 105-Tightening bolt; 106-Top clamp; 107-Stiffening rib; 108-Infill material; 109-Dummy joint; 201-Longitudinal reinforcement; 202-Outline stirrup; 203-First interface reinforcement; 204-Second interface reinforcement. Detailed Implementation

[0080] The present invention will now be described in detail with reference to the accompanying drawings.

[0081] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0082] Example 1

[0083] like Figures 1 to 8As shown, this embodiment uses a prefabricated crash barrier, which includes a prefabricated shell 1 and a reinforcing cage 2. The prefabricated shell 1 includes an inner baffle 101 and an outer baffle 102. The inner baffle 101 and the outer baffle 102 are arranged side by side and spaced apart. The reinforcing cage 2 is arranged between the outer baffle 102 and the inner baffle 101. The space between the outer baffle 102 and the inner baffle 101 is filled with a concrete structure 3. The bottom of the outer baffle 102 can be connected to the side main beam 6. The bottom of the inner baffle 101 can be connected to the bridge deck reinforcing steel 51.

[0084] Specifically, both the outer baffle 102 and the inner baffle 101 are prefabricated components in the factory; and the length of a single outer baffle 102 and a single inner baffle 101 is Ls, where 2m≤Ls≤4m, thus facilitating manufacturing, transportation and hoisting.

[0085] A Z-shaped bend is provided at the bottom of the outer baffle 102; the Z-shaped bend is used to connect the outer edge of the side main beam 6; specifically, a number of mounting through holes are provided on the horizontal surface of the Z-shaped bend, which are spaced apart along the length of the outer baffle 102; when the outer baffle 102 is connected to the side main beam 6, the Z-shaped bend fits against the outer edge of the side main beam 6, and a sealing bolt is inserted into each mounting through hole, thereby connecting the outer baffle 102 to the side main beam 6 through the sealing bolt; and the lower edge of the Z-shaped bend is lower than the lower bottom surface of the top plate 61 of the side main beam, thereby playing a role in rainwater protection and reducing the erosion of the side main beam 6 by rainwater.

[0086] A stiffening rib 107 is also provided on the side of the Z-shaped bend facing away from the inner baffle 101, thereby providing transverse support for the outer baffle 102 along the bridge. This prevents concrete from squeezing the inner wall of the outer baffle 102 when concrete is poured between the outer baffle 102 and the inner baffle 101, thus avoiding out-of-plane deformation and local instability of the outer baffle 102. At the same time, the stiffening rib 107 can also increase the overall torsional moment of inertia of the crash barrier in this embodiment, improving the crash barrier's anti-overturning ability in vehicle collision scenarios. The material of the stiffening rib 107 is the same as that of the outer baffle 102. For example, if the outer baffle 102 is a steel structure, then the stiffening rib 107 is also made of steel and welded to the outer baffle 102. When the outer baffle 102 is made of high-strength and high-toughness concrete, the stiffening rib 107 is also made of concrete and is prefabricated in the same mold as the outer baffle 102.

[0087] The inner baffle 101 is the impact surface of the out-of-control vehicle, and its shape is as follows: Figures 1 to 4As shown, the design follows the anti-collision level requirements of relevant specifications. A first edge-sealing angle steel 103 is provided at the bottom of the inner baffle 101. Specifically, the first edge-sealing angle steel 103 is provided on the side of the inner baffle 101 away from the outer baffle 102, thereby avoiding difficulties in the flow of concrete. At the same time, the inner baffle 101 can be welded to the bridge deck reinforcement 51 through the first edge-sealing angle steel 103. Specifically, in this embodiment, the inner baffle 101 is welded to the transverse reinforcement in the bridge deck reinforcement 51 through the first edge-sealing angle steel 103.

[0088] The inner baffle 101 and the outer baffle 102 are both provided with second edge angle steel 104 along the longitudinal direction of the bridge, so that two adjacent outer baffles 102 or inner baffles 101 along the longitudinal direction of the bridge can be stably connected by welding the second edge angle steel 104.

[0089] The top of the prefabricated shell 1 also includes a top clamp 106; the top clamp 106 is used to prevent the inner baffle 101 and the outer baffle 102 from moving away from each other; specifically, the clamp is arranged transversely along the bridge, and the shapes of its two ends correspond to the shapes of the top of the outer baffle 102 and the top of the inner baffle 101, respectively, so that its two ends can be fastened to the top of the outer baffle 102 and the top of the inner baffle 101, respectively, and prevent the outer baffle 102 and the inner baffle 101 from moving away from each other; in this embodiment, the number of clamps is greater than one, and the clamps are distributed at intervals along the length direction of the inner baffle 101, so that concrete can be poured between the outer baffle 102 and the inner baffle 101 using the gap between two clamps; in this embodiment, self-compacting concrete of grade C30 to C50 is used when pouring concrete, which can achieve automatic compaction without the need for manual vibration to assist compaction, saving labor, and the vibration-free construction greatly reduces construction noise, which is environmentally friendly.

[0090] The reinforcing cage 2 includes longitudinal reinforcing bars 201 and contour stirrups 202. The longitudinal reinforcing bars 201 are set along the length of the prefabricated shell 1 to replace part of the concrete in bearing tensile and compressive stress, thereby improving the load-bearing capacity of the crash barrier and the impact resistance of the crash barrier structure. The specific quantity and spacing parameters are determined based on the external loads, such as self-weight and vehicle loads, as well as the combined load-bearing capacity of the crash barrier and the side main beam 6. The contour stirrups 202 are set along the cross-section of the prefabricated shell 1 and are distributed at intervals along the length of the prefabricated shell 1. Their shape fits the inner wall of the prefabricated shell 1, but the net distance between the edge of the contour stirrups 202 and the inner wall of the prefabricated shell 1 should meet the relevant specifications. The contour stirrups 202 provide shear bearing capacity for the crash barrier structure and, together with the longitudinal reinforcing bars, form a reinforcing cage, providing a certain rigidity during hoisting and installation to prevent excessive deformation of the prefabricated reinforcing cage 2 unit during transportation and hoisting.

[0091] The steel cage 2 is also a prefabricated component in the factory. The length of a single steel cage 2 is Lc, which corresponds to the length Ls of a single outer baffle 102 or a single inner baffle 101, i.e., 2m≤Lc≤4m; however, both ends of the longitudinal steel bars 201 extend 10 to 20cm beyond the ends of the outer baffle 102 or the inner baffle 101, so that two adjacent steel cages 2 along the longitudinal direction of the bridge are stably connected by the mutual lap of the longitudinal steel bars 201.

[0092] The reinforcing cage 2 also includes a first interface reinforcing bar 203 and a second interface reinforcing bar 204; both the first interface reinforcing bar 203 and the second interface reinforcing bar 204 are arranged along the cross-section of the prefabricated shell 1 and are spaced apart along the length of the prefabricated shell 1; wherein, a single first interface reinforcing bar 203 is as follows: Figure 5 The shape shown is a right-angled trapezoid, and it is welded to the transverse reinforcement in the bridge deck reinforcement 51; a single second interface reinforcement 204 is as follows Figure 6 The structure is rectangular and welded to the top of the side main beam 6. Specifically, if the side main beam 6 is an I-beam, the second interface steel bar 204 is directly welded to the top plate 61 of the side main beam; if the side main beam 6 is a concrete beam, the second interface steel bar 204 is welded to the pre-embedded steel bar 62 of the side main beam.

[0093] When constructing the prefabricated crash barrier of this embodiment, the following steps can be referred to:

[0094] A. The factory prefabricates the assembled shell 1 and the steel cage 2 in sections, and then transports the assembled shell 1 and the steel cage 2 to the construction site.

[0095] B. Place the steel cage 2 in the predetermined position, and weld the first interface steel bar 203 and the transverse steel bar in the bridge deck steel bar 51 together. Connect the second interface steel bar 204 to the top plate 61 of the side main beam or the pre-embedded steel bar 62 of the side main beam to realize the installation and positioning of the steel cage 2. For two steel cages 2 that are adjacent along the longitudinal direction of the bridge, overlap the longitudinal steel bars 201 at the corresponding ends of the two adjacent steel cages 2 and weld them together to realize the connection of the two adjacent steel cages 2.

[0096] C. The prefabricated shell 1 is set in a predetermined position, wherein the Z-shaped bend of the outer baffle 102 is fitted with the top and outer edge of the side main beam 6, and the Z-shaped bend is connected to the side main beam 6 by tightening bolts 105; the inner baffle 101 is welded to the top layer of steel reinforcement of the bridge deck 5 by its first edge angle steel 103.

[0097] D. Install clamps on the top of the prefabricated shell 1; the clamps are spaced apart along the length of the prefabricated shell 1; pour self-compacting concrete into the prefabricated shell 1 through the opening between two adjacent clamps to form a concrete structure 3; after the pouring is completed, cover the top of the prefabricated outer side with a thick plastic film and allow it to cure naturally until the crash barrier is formed.

[0098] Example 2

[0099] like Figures 8 to 11 As shown, the bridge used in this embodiment includes several bridge spans 4 and a prefabricated crash barrier as described in Embodiment 1; the prefabricated crash barriers are distributed along the longitudinal direction of the bridge; two prefabricated crash barriers that are adjacent along the longitudinal direction of the bridge and located on the same bridge span 4 are fixedly connected; two prefabricated crash barriers that are adjacent along the longitudinal direction of the bridge but located on different bridge spans 4 are not fixedly connected.

[0100] Specifically, such as Figure 8 and Figure 9 As shown, all prefabricated crash barriers on the same bridge span 4 are connected end to end and linked together by welding corresponding second edge angle steel 104; two prefabricated crash barriers located on two different bridge spans 4 but adjacent along the longitudinal direction of the bridge are not directly connected, but only... Figure 10 As shown, filler material 108, such as foam plastic, is inserted between the two prefabricated crash barriers.

[0101] Meanwhile, since the prefabricated crash barriers located on the same bridge span 4 in this embodiment are interconnected without any gaps, in order to allow the prefabricated crash barriers to freely expand and contract under the influence of ambient temperature, a dummy joint 109 is also provided at the top of the prefabricated crash barriers, running transversely through the prefabricated crash barriers along the bridge; specifically, as shown... Figure 11 As shown, the depth of the dummy joint 109 is Dg; the width of the dummy joint 109 along the longitudinal direction of the bridge is Wg; 20mm≤Dg≤30mm; 2mm≤Wg≤4mm; the top edge of the dummy joint 109 is chamfered by grinding with a grinding wheel to avoid stress concentration.

[0102] To further ensure the reliable connection between the prefabricated crash barrier and the side main beam 6, thereby ensuring that the prefabricated crash barrier and the side main beam 6 work together to prevent shear slippage of the connection layer, this embodiment also provides additional shear-resistant connectors on the side main beam 6 to connect with the prefabricated crash barrier. Specifically, for the concrete side main beam 6, shear-resistant steel bars that can extend into the prefabricated crash barrier can be pre-embedded in the top of the side main beam 6; for the steel structure side main beam 6, shear-resistant studs or perforated shear-resistant steel plates that can extend into the prefabricated crash barrier can be provided on the top surface of the side main beam 6.

[0103] like Figure 1 and Figure 2 As shown, the width of the prefabricated crash barrier in this embodiment is W, where W = 750mm, thereby improving the load-bearing capacity of the bridge; the specific proof steps are as follows:

[0104] Taking a concrete T-beam as an example, such as Figure 12 and Figure 13As shown, point II is the point of application of the resultant force of the compression reinforcement, point III is the point of application of the resultant force of the tension reinforcement, point IV is the compression reinforcement, and point V is the tension reinforcement; the width of the prefabricated crash barrier is b, the height of the barrier is h, the width of the top plate 61 of the side main beam is B, the height of the main beam is H, the distance from the point of application of the resultant force of the tension reinforcement to the bottom of the main beam is as, the distance from the point of application of the resultant force of the compression reinforcement to the top of the main beam is a's, the cross-sectional area of ​​the tension reinforcement is As, the cross-sectional area of ​​the compression reinforcement is A's, the design value of the concrete compressive strength is fcd, and the design value of the tensile / compressive strength of the reinforcement is fsd;

[0105] For a simply supported beam structure, the bending moment effect of the main beam caused by the self-weight of the prefabricated crash barrier is:

[0106] ΔW=γbhl 2 / 8

[0107] In the formula: γ is the unit weight of the guardrail concrete, and l is the span of the main beam.

[0108] The increase in the load-bearing capacity of the main beam due to the prefabricated crash barrier is denoted as ΔR, which is the difference between the bending load-bearing capacity R1 after considering the prefabricated crash barrier and the bending load-bearing capacity R2 without considering the prefabricated crash barrier.

[0109] ΔR=R1-R2

[0110] The optimal design range for the width of prefabricated crash barriers is required to be ΔR > ΔW, meaning that the effect of increasing the bridge's load-bearing capacity is greater than the adverse effects brought to the bridge by the increase in its own weight.

[0111] The calculation process for the bending bearing capacity R2 without considering prefabricated crash barriers is as follows:

[0112] According to the principle of mechanical equilibrium:

[0113] f cd Bx′+f sd A's = f sd As

[0114] The height of the main beam's compression zone is not considered when using prefabricated crash barriers.

[0115]

[0116] Taking the moment at the point of application of the resultant force of the steel reinforcement in the tension zone yields the bending bearing capacity without considering prefabricated crash barriers:

[0117] R2=f cd Bx′(H-0.5x′-as)+f sd A′s(H-as-a′s)

[0118] The calculation process for the bending load capacity R1 of prefabricated crash barriers is as follows:

[0119] According to the principle of mechanical equilibrium:

[0120] f cd bh+f cd Bx+f sd A's = f sd As

[0121] Then consider the height of the main beam compression zone when using prefabricated crash barriers:

[0122]

[0123] Taking the moment at the point of application of the resultant force of the steel reinforcement in the tension zone yields the bending bearing capacity considering prefabricated crash barriers:

[0124] R1=f cd bh(h+H-as)+f cd Bx(H-0.5x-as)+f sd A′s(H-as-a′s)

[0125] but:

[0126] ΔR=R1-R2=f cd bh(h+H-as)+f cd Bx(H-0.5x-as)-f cd Bx′(H-0.5x′-as)

[0127] Substituting x and x', we get:

[0128]

[0129] Let f(b) = ΔR - ΔW, then:

[0130]

[0131] Since the height of the prefabricated crash barrier must meet crash protection requirements and specifications, its height h cannot be changed. Therefore, in the above formula, parameters such as the main beam span, main beam height, main beam width, prefabricated crash barrier height, and the position and area of ​​the reinforcing bars become constants once they are included, and the above formula becomes a function of the width of the prefabricated crash barrier.

[0132] Differentiating f(b) yields:

[0133]

[0134] f′(b) is a linear function of b. Letting f′(b) = 0, we have a unique solution:

[0135] b = b *

[0136] When b < b * When f′(b) > 0, f(b) is monotonically increasing; when b > b * If f′(b) < 0, and f(b) is monotonically decreasing, then b = b * This is the maximum point of f(b), where ΔR-ΔW is at its maximum. The prefabricated crash barrier can fully enhance the load-bearing capacity of the main beam, making its effect on the bridge's load-bearing capacity greater than the adverse effects on the bridge caused by the increase in its own weight.

[0137] Based on calculations and analyses of different structures (concrete T-beams, concrete box girders, and I-beams) and different spans (20–40m), the optimal width b for prefabricated crash barriers was determined. * The ideal value is 65cm to 85cm, and this example uses the middle value of 75cm.

[0138] To verify the improved load-bearing capacity of the bridge used in this embodiment, this embodiment also calculated the difference in stress between the bridge with the prefabricated crash barrier installed in this embodiment and the bridge with ordinary crash barriers. The specific calculation examples are as follows:

[0139] Example 1:

[0140] The steel plate composite beam adopts I-shaped steel main beams; the length and width of the steel plate composite beam are 30m and 20.75m respectively, and it is designed as a one-way four-lane road with a load rating of Highway-I.

[0141] When the bridge adopts the prefabricated crash barrier of this embodiment, the parameters of the prefabricated crash barrier are as described above, with a width of 750mm and a self-weight of 20KN / m.

[0142] When the bridge uses ordinary crash barriers, the width and weight of the ordinary crash barriers are 500mm and 12KN / m, respectively.

[0143] The structural response of the bridge obtained from simulation calculations is as follows:

[0144] When the bridge adopts the prefabricated anti-collision guardrail of this embodiment, the mid-span stress of the steel main beam during normal use is 154MPa, the mid-span deformation of the steel main beam under vehicle action is 17mm, and the structural fundamental frequency is 3.19Hz.

[0145] When the bridge uses ordinary crash barriers, the mid-span stress of the steel main beam during normal use is 196MPa, the mid-span deformation of the steel main beam under vehicle load is 24mm, and the structural fundamental frequency is 2.41Hz.

[0146] As shown in this example, although the prefabricated crash barrier in this embodiment is heavier than the ordinary crash barrier, the prefabricated crash barrier and the side main beam 6 form a composite structural system in the beam height direction. Therefore, the prefabricated crash barrier scheme of this embodiment is adopted. Compared with the scheme using ordinary crash barriers, it can reduce the stress of the steel main beam in the normal service stage by about 21%, which significantly reduces the stress level of the steel main beam and provides the structural safety of the main beam. At the same time, the deformation under vehicle action is reduced by about 29%, which improves the stiffness of the bridge structure and strengthens its resistance to deformation. The fundamental frequency of the structure increases by about 32%, indicating that the prefabricated crash barrier scheme of this embodiment has better overall stiffness.

[0147] Example 2:

[0148] The concrete T-beams are used as the main beams; the length and width of the concrete T-beams are 30m and 12.6m respectively, designed for one-way three lanes, and the load level is Highway-I.

[0149] When the bridge adopts the prefabricated crash barrier of this embodiment, the parameters of the prefabricated crash barrier are as described above, with a width of 750mm and a self-weight of 20KN / m.

[0150] When the bridge uses ordinary crash barriers, the width and weight of the ordinary crash barriers are 500mm and 12KN / m, respectively.

[0151] The structural response of the bridge obtained from simulation calculations is as follows:

[0152] When the bridge adopts the prefabricated anti-collision guardrail of this embodiment, the stress at the lower edge of the T-shaped concrete beam at the mid-span is -9.7MPa during normal use, the mid-span deformation of the T-shaped concrete beam under vehicle action is 6.46mm, and the structural fundamental frequency is 5.39Hz.

[0153] When the bridge uses ordinary crash barriers, the stress at the lower edge of the T-shaped concrete beam at mid-span is -9.2MPa during normal use, the mid-span deformation of the T-shaped concrete beam under vehicle load is 11.98mm, and the structural fundamental frequency is 4.83Hz.

[0154] As shown in this example, although the prefabricated crash barrier in this embodiment is heavier than the ordinary crash barrier, the prefabricated crash barrier and the side main beam 6 form a composite structural system in the beam height direction. Therefore, the prefabricated crash barrier scheme of this embodiment is adopted. Compared with the scheme using the ordinary crash barrier, the T-shaped concrete beam has a higher lower edge compressive stress reserve during normal use, which is increased by about 5.4%, reducing the risk of tensile cracking of the T-shaped concrete beam; the deformation under vehicle action is reduced by about 46%, which improves the stiffness of the bridge structure and strengthens its deformation resistance; the structural fundamental frequency increases by about 12%, indicating that the scheme using the prefabricated crash barrier of this embodiment has better overall stiffness.

[0155] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A prefabricated crash barrier, characterized in that, The prefabricated guardrail comprises a prefabricated shell (1) and a reinforcing cage (2); the prefabricated shell (1) comprises an inner baffle (101) and an outer baffle (102); the inner baffle (101) and the outer baffle (102) are arranged side by side and spaced apart; the reinforcing cage (2) is disposed between the outer baffle (102) and the inner baffle (101); a concrete structure (3) is also filled between the outer baffle (102) and the inner baffle (101); the bottom of the outer baffle (102) can be connected to the side main beam (6); the bottom of the inner baffle (101) can be connected to the bridge deck reinforcement (51); the width of the prefabricated crash barrier satisfies the following formula: In the formula, 1 is the design value of concrete compressive strength; b is the width of the prefabricated crash barrier; h is the height of the prefabricated crash barrier; fsd is the design value of steel reinforcement tensile / compressive strength. The cross-sectional area of ​​the tensile reinforcement; This represents the cross-sectional area of ​​the compressed reinforcing steel. The width of the top plate (61) of the side main beam; The density of the concrete for the guardrail; l The main beam span.

2. The prefabricated crash barrier according to claim 1, characterized in that, The steel cage (2) and the bridge deck steel bars (51) are interconnected, as are the steel cage (2) and the top of the side main beam (6).

3. A prefabricated crash barrier according to any one of claims 1 to 2, characterized in that, The steel cage (2) also includes longitudinal steel bars (201); the longitudinal steel bars (201) are arranged along the length direction of the prefabricated shell (1); the two ends of the longitudinal steel bars (201) extend out of the two ends of the prefabricated shell (1).

4. A prefabricated crash barrier according to any one of claims 1 to 2, characterized in that, The bottom of the inner baffle (101) is provided with a first edge-sealing angle steel (103); the first edge-sealing angle steel (103) is provided along the longitudinal direction of the bridge; the inner baffle (101) and the outer baffle (102) are both provided with second edge-sealing angle steel (104) along the longitudinal direction of the bridge; the second edge-sealing angle steel (104) is provided along the corresponding edges of the inner baffle (101) and the outer baffle (102).

5. A prefabricated crash barrier according to any one of claims 1 to 2, characterized in that, The top of the assembled housing (1) also includes a top clamp (106); the two ends of the top clamp (106) are respectively connected to the inner baffle (101) and the outer baffle (102); the top clamp (106) is used to prevent the inner baffle (101) and the outer baffle (102) from moving away from each other or deflecting.

6. A prefabricated crash barrier according to any one of claims 1 to 2, characterized in that, The bottom of the outer baffle (102) is provided with a Z-shaped bend; the Z-shaped bend is used to connect the outer edge of the side main beam (6).

7. A construction method for a prefabricated crash barrier, characterized in that, Applied to any of the prefabricated crash barriers as described in claims 1 to 6, comprising the following steps: A. Connect the steel cage (2) to the predetermined position on the bridge; B. Connect the outer baffle (102) to the outer edge of the side main beam (6); connect the inner baffle (101) to the bridge deck reinforcement (51); connect the two ends of the clamp to the outer baffle (102) and the inner baffle (101) respectively. C. Pour concrete between the outer baffle (102) and the inner baffle (101).

8. A bridge comprising several spans (4), characterized in that, It also includes several prefabricated crash barriers as described in any one of claims 1 to 6; the prefabricated crash barriers are distributed longitudinally along the bridge; two prefabricated crash barriers located on the same bridge span (4) and adjacent in the longitudinal direction are fixedly connected; and a gap is provided between two prefabricated crash barriers located on different bridge spans (4) and adjacent in the longitudinal direction.

9. A bridge according to claim 8, characterized in that, The width of the prefabricated shell (1) along the transverse direction of the bridge is W; 650mm≤W≤850mm.

10. A bridge according to claim 8, characterized in that, The top of the prefabricated crash barrier is provided with a dummy joint (109) along the transverse direction of the bridge; the dummy joint (109) is provided along the transverse direction of the bridge; the depth of the dummy joint (109) is Dg; the width of the dummy joint (109) along the longitudinal direction of the bridge is Wg; 20mm≤Dg≤30mm; 2mm≤Wg≤4mm.

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