Rapidly-erected assembly type structure spanning old bridge and culvert

Abstract

The utility model discloses a quickly-erected assembly type structure spanning an old bridge and culvert, and belongs to the technical field of emergency equipment structure design. The assembly type structure comprises an approach plate, a bridge span plate, a support, a pin rod and a cushion block, and the approach plate and the bridge span plate are made of aviation aluminum alloy 7075 materials. The support is placed at the joint of the approach plate and the bridge span plate, two rows of pin hole seats are arranged above the support, the bridge span plate is installed on the row, close to the midspan, of the two rows of pin hole seats, the approach bridge plate is installed on the other row of pin hole seats, and pin penetrating holes are formed in the positions, corresponding to the support, of the bridge span plate and the approach bridge plate. The supports, the approach plate and the bridge span plate are connected into a whole through pin rods, and a cushion block is arranged between the approach plate and the bridge floor and fixed to the approach plate through studs. The assembly type structure has the advantages of being light in self weight, high in erecting speed and high in bearing capacity.

Description

Technical Field

[0001] This utility model relates to the field of emergency equipment structural design technology, specifically to a prefabricated structure for rapid erection across old bridges and culverts. Background Technology

[0002] In engineering construction, there are situations where large equipment needs to cross old bridges and culverts with insufficient load-bearing capacity. Demolishing and rebuilding these old bridges and culverts is not only expensive and time-consuming, but it also affects local traffic. However, if prefabricated bridges that can be erected quickly are used to directly cross the bridges and culverts, a series of long-term and costly problems such as demolition, reconstruction, or reinforcement of old bridges and culverts can be avoided, thus greatly improving transportation efficiency.

[0003] Currently, the main components of mature prefabricated bridges are typically made of steel. While this ensures the bridge's load-bearing capacity, the excessive weight of the bridge structure increases the difficulty of assembly and transportation. Furthermore, existing prefabricated bridges usually use PP joints or single / double-ear connections for component connections. PP joints require not only the PP and TD joints themselves, but also PP joint connectors at the bridge span ends, pin assemblies, and top blocks. Therefore, PP joints require a large number of connecting components and have high manufacturing costs. While single / double-ear connections are structurally simple, each connection point requires a corresponding pin, also resulting in a large number of connecting components, which inevitably slows down the erection speed of prefabricated bridges. Utility Model Content

[0004] In view of this, the present invention provides a prefabricated structure for rapid erection across old bridges and culverts. It adopts a high-strength aluminum alloy bridge span plate with a V-shaped web structure as the main component to form a prefabricated load-bearing structure for crossing old bridges and culverts. This structure has the characteristics of light weight, fast erection speed and strong load-bearing capacity.

[0005] A prefabricated structure for rapid erection across old bridges and culverts includes approach slabs, bridge span slabs, supports, pins, and pads. The approach slabs and bridge span slabs are made of aerospace-grade aluminum alloy 7075.

[0006] The overall shape of the bridge span slab is a large-angle V-shape, with a pre-camber at the mid-span, and the interior of the bridge span slab is a hollow load-bearing structure.

[0007] The support is provided with two rows of pin holes above it, which are used to connect the approach plate and the bridge span plate respectively.

[0008] The support is placed at the junction of the approach slab and the bridge span slab. One row of the two rows of pin hole seats near the span is used to install the bridge span slab, and the other row is used to install the approach slab. The bridge span slab and the approach slab have pin holes at the corresponding support positions. After installation, the support, approach slab and bridge span slab are connected to form a whole by pins. A pad is provided between the approach slab and the bridge deck. The pad is fixed to the approach slab by studs.

[0009] Furthermore, the bridge span plate is composed of a top plate, a bottom plate, side plates, and a V-shaped web plate. The top plate, bottom plate, and side plates together form a hollow shell with a rectangular cross-section, and the V-shaped web plate is set inside the hollow shell to support it.

[0010] Furthermore, the bridge span slab has an 80mm pre-camber at mid-span.

[0011] Furthermore, the bridge span plate is made of aluminum alloy plate with a total height of 90mm and a span length of 4000mm and a width of 998mm. The thickness of the top plate, bottom plate and side plate is 6mm, and the thickness of the V-shaped web plate is 5mm. The approach plate is made of solid aluminum alloy plate with a thickness of 25mm and a span length of 2000mm and a width of 998mm.

[0012] Furthermore, the pin is made of HPB300 round steel bar with a diameter of 18mm.

[0013] Furthermore, the bridge span has two or more spans, and the bridge spans are also connected by supports and pins.

[0014] Beneficial effects:

[0015] 1. The main structure of this utility model consists of three parts: approach plates on both sides and bridge span plate in the middle. The approach plates and bridge span plate can be assembled and connected by supports and pins. Due to the small number of parts and the simple connection structure, the assembly and erection speed is fast. In addition, the aviation aluminum alloy 7075 material has the comprehensive advantages of being lightweight, high-strength and high-hardness. The prefabricated load-bearing structure has a light overall weight and strong load-bearing capacity.

[0016] 2. The bridge slab of this utility model has an 80mm pre-camber at mid-span. The purpose of the large pre-camber is that the structural slab is relatively thin, and the structural deflection is large under live load. This can prevent the bottom surface of the bridge slab from contacting the bridge deck too early. The bridge slab has a small slab thickness to correspond to the large vertical deformation under load. As the load increases further, the bridge slab is allowed to contact the old bridge deck, so as to give full play to the joint bearing role of the bridge slab and the old bridge culvert. The reasonable setting of the pre-camber can keep the longitudinal slope of the bridge slab within 3%.

[0017] 3. The 90mm thick bridge slab of this utility model can meet the requirements of vehicle load and highway Class II load, with the maximum stress controlled within 208MPa and the maximum vertical deflection controlled within 80mm. The minimum structural stability coefficient is 7.59. The 25mm thick approach slab can meet the requirements of vehicle load and highway Class II load, with the maximum stress controlled within 140MPa and the maximum vertical deflection controlled within 5.9mm, thus meeting the structural stability requirements. Attached Figure Description

[0018] Figure 1 Elevation layout of the prefabricated structure spanning the old culvert for rapid erection.

[0019] Figure 2 A plan view of a prefabricated structure for rapid erection across an old culvert;

[0020] Figure 3 This is a cross-sectional view of the bridge span slab;

[0021] Figure 4 This is an elevation view of the approach slab and its supports.

[0022] Among them, 1-approach plate, 2-bridge span plate, 3-support, 3-1-pin hole seat, 4-pad block. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] Taking a versatile 4m span prefabricated structure that can span most culverts and circular pipe culverts as an example, the elevation drawing is shown below. Figure 1 As shown, see the floor plan. Figure 2 As shown. The prefabricated structure for rapid erection of old culverts of this utility model consists of three parts: approach slabs 1 on both sides and bridge span slab 2 in the middle. The connecting and supporting components include supports 3, pads 4 and pins.

[0025] Bridge span slab 2 is constructed of 90mm thick aluminum alloy plate with a span length of 4000mm and a width of 998mm, consisting of three slabs arranged transversely. The bridge span slab comprises 6mm thick top and bottom plates and 5mm thick V-shaped web plates; its cross-sectional layout is shown in the diagram. Figure 3As shown, an 80mm pre-camber is provided at the mid-span. The purpose of this large pre-camber is to prevent premature contact between the bottom surface of the bridge slab 2 and the bridge deck, given the relatively thin structural slab. The ends of the bridge slab 2 are placed on 20mm thick aluminum alloy supports 3. The aluminum alloy supports 3 are 300mm wide and 3100mm long, and are shared by the approach slab 1 and the bridge slab 2 at the junction. The top of the supports 3 has two rows of pin holes 3-1 with a transverse bridge spacing of 998mm. The row near the mid-span is used to install the bridge slab, and the other row is used to install the approach slab 1. The bridge slab 2 has pin holes at the supports 3. After installation, the supports 3 and the bridge slab 2 are connected to each other as a whole by pins.

[0026] The approach ramp 1 is made of 25mm thick solid aluminum alloy plate, with a span of 2000mm and a width of 998mm, and three plates are arranged transversely. Two aluminum alloy spacers 4 are installed at 650mm intervals in the middle, and the spacers 4 are fixed to the approach ramp 1 with studs. The approach ramp 1 has through holes at the supports 3; after installation, the supports 3 and the approach ramp 1 are connected to form a whole using pins. See the detailed drawing of the support accessories. Figure 4 As shown. The purpose of setting the approach slab 1 is mainly to achieve a longitudinal slope transition of 110mm at the end of the bridge span slab, which is generally controlled at a longitudinal slope of 3-5%.

[0027] The pin is made of HPB300 round steel bar with a diameter of 18mm.

[0028] The mass statistics of the entire bridge structural unit are shown in Table 1.

[0029] Table 1. Statistical Table of Overall Bridge Component Quality

[0030]

[0031] In addition, approach slab 1 and bridge span slab 2 are made of aerospace aluminum alloy 7075. The emergence of aerospace aluminum alloy 7075 provides a high-quality material choice for rapidly erected prefabricated bridges. This material has the comprehensive advantages of being lightweight, high-strength, and high-hardness. Its performance comparison with steel and ordinary aluminum alloys is shown in Table 2.

[0032] Table 2 Comparison of Material Properties

[0033]

[0034]

[0035] The load-bearing capacity of the bridge span slab and approach slabs were analyzed using plate elements. Vehicle loads were used as the live load, considering three arrangement methods: the most unfavorable load at the mid-span, the most unfavorable load at L / 4, and the most unfavorable load at the support. The most unfavorable load arrangement was two 140kN rear axles with wheel pressures spaced 1.4m apart on each side, with an area of ​​200mm × 600mm. The boundary conditions of the bridge span slab calculation model were: one end constrained for displacement in three directions, and the other end constrained for vertical displacement. Under the heavy axle wheel pressure of the vehicle load, the maximum equivalent stress of the structure under the most unfavorable load arrangement at the mid-span was 208MPa, located at the boundary constraint. Excluding this point, the stress distribution in other areas was within 160MPa. Because the boundary constraint was a nodal constraint, stress concentration occurred. Considering that the actual slab was placed on a pad, the stress distribution was relatively uniform, and peak reduction was appropriate. Under the most unfavorable load arrangement at the end, the maximum equivalent stress of the structure was 169MPa, and the overall stress effect was smaller than that under the mid-span load arrangement. Considering the impact coefficient of 1.45 and the combination coefficient of 1.4, the maximum equivalent stress is 320 MPa, and the design stress of 7075 is 400 MPa, which is within the safe range. Under the heavy axle wheel pressure of vehicle load, the maximum vertical displacement of the structure under the most unfavorable load distribution at the span is 79.2 mm, and the maximum vertical displacement of the structure under the most unfavorable load distribution at the end is 50.3 mm. Although the structural displacement is greater than the limit of the highway code, considering the 80 mm precamber setting, the displacement energy of the structure under live load can control the longitudinal alignment within 3%. The design concept of the bridge slab is to use a small slab thickness (the thickness of the bridge slab is only 1 / 44 of its span) to correspond to a small vertical stiffness of the structure, which can produce a large vertical deformation under load. Under the design load, the bridge slab does not contact the old bridge deck below it. As the load increases further, the bridge slab is allowed to contact the old bridge deck, so as to give full play to the joint load-bearing role of the bridge slab and the old bridge culvert, but it is necessary to ensure that the bridge slab is always in an elastic stress state. Large vertical deformations under load can be balanced by setting a pre-camber. An 80mm pre-camber is just enough to balance the 80mm vertical displacement under vehicle load, thus ensuring that the longitudinal slope of the bridge slab is always controlled within 3%.

[0036] The approach ramp slab is also analyzed using plate elements. Since the approach ramp slab is a solid slab with a thickness of 25mm, one layer of plate elements is sufficient. The boundary conditions of the model are: one end constrains displacement in three directions, and the middle and the other end constrain vertical displacement. The longitudinal spacing of the constraint points is 650mm. Considering the most unfavorable load distribution in the three spans, under the three most unfavorable load distributions, the maximum equivalent stress of the approach ramp slab is 139.2MPa; under the three most unfavorable load distributions, the maximum vertical displacement of the approach ramp slab is 5.9mm. The overall and local stability of the approach ramp slab are then examined.

[0037] It is evident that the 90mm thick bridge slab can meet the requirements of vehicle load and Highway Class II load, with the maximum stress controlled within 208MPa, the maximum vertical deflection controlled within 80mm, and the minimum structural stability coefficient of 7.59, thus meeting the structural stability requirements. The 25mm thick approach slab can also meet the requirements of vehicle load and Highway Class II load, with the maximum stress controlled within 140MPa and the maximum vertical deflection controlled within 5.9mm, indicating no issues with structural stability.

[0038] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A prefabricated structure for rapid erection across existing bridges and culverts, characterized in that, It includes approach ramps, bridge spans, supports, pins, and pads. The approach ramps and bridge spans are made of aerospace-grade aluminum alloy 7075. The overall shape of the bridge span slab is a large-angle V-shape, with a pre-camber at the mid-span, and the interior of the bridge span slab is a hollow load-bearing structure. The support is provided with two rows of pin holes above it, which are used to connect the approach plate and the bridge span plate respectively. The support is placed at the junction of the approach slab and the bridge span slab. One row of the two rows of pin hole seats near the span is used to install the bridge span slab, and the other row is used to install the approach slab. The bridge span slab and the approach slab have pin holes at the corresponding support positions. After installation, the support, approach slab and bridge span slab are connected to form a whole by pins. A pad is provided between the approach slab and the bridge deck. The pad is fixed to the approach slab by studs.

2. The prefabricated structure for rapid erection across old bridges and culverts as described in claim 1, characterized in that, The bridge span is composed of a top plate, a bottom plate, side plates, and a V-shaped web. The top plate, bottom plate, and side plates together form a hollow shell with a rectangular cross-section, and the V-shaped web is set inside the hollow shell to support it.

3. The prefabricated structure for rapid erection across old bridges and culverts as described in claim 2, characterized in that, The bridge slab has an 80mm pre-camber at mid-span.

4. The prefabricated structure for rapid erection across old bridges and culverts as described in claim 3, characterized in that, The bridge span is made of aluminum alloy plate with a total height of 90mm and a span length of 4000mm and a width of 998mm. The thickness of the top plate, bottom plate and side plate is 6mm, and the thickness of the V-shaped web plate is 5mm. The approach road plate is made of solid aluminum alloy plate with a thickness of 25mm and a span length of 2000mm and a width of 998mm.

5. The prefabricated structure for rapid erection across old bridges and culverts as described in claim 4, characterized in that, The pin is made of HPB300 round steel bar with a diameter of 18mm.

6. The prefabricated structure for rapid erection across existing bridges and culverts as described in claim 4 or 5, characterized in that, The bridge span consists of two or more spans, and the bridge spans are connected by supports and pins.

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