Variable-thickness assembly type structure capable of being rapidly erected and spanning old culvert

Abstract

The invention discloses a variable-thickness assembly type structure capable of being rapidly erected and spanning an old culvert, and belongs to the technical field of emergency equipment structure design. The assembly type structure comprises a left side bearing plate, a right side bearing plate, a support base plate, a pin rod and a stud; the left side bearing plate, the right side bearing plate and the support base plate are all made of high-strength aluminum alloy 7075 materials. The left side bearing plate and the right side bearing plate are arranged in a wedge shape in the longitudinal direction, clamping grooves formed together with the bearing plates are formed in the middle lower edge of the midspan position, and the left and right sides are staggered; the clamping grooves of the left side bearing plate and the right side bearing plate are embedded in place and then connected through pin rods to form 80 mm pre-camber, support base plates are arranged at the bottoms of the other ends of the left side bearing plate and the right side bearing plate, and the left side bearing plate and the right side bearing plate are connected with the support base plates through studs. The variable cross-section bearing plates are assembled and connected through the midspan pin rods to form the combined bearing high-strength aluminum alloy bridge span plate bearing structure, and the structure has the advantages of being ultra-light in self weight, high in erecting speed and high in bearing capacity.

Description

Technical Field

[0001] The invention relates to the technical field of emergency equipment structure design, and in particular to a variable thickness assembled structure that can be quickly erected across an old culvert. Background Art

[0002] During engineering construction, large equipment may need to cross old bridges and culverts with insufficient carrying capacity. If these old bridges and culverts are demolished and rebuilt, it will not only be expensive and time-consuming, but will also affect local traffic. If fast-erected prefabricated bridges are used to directly cross the bridges and culverts, a series of long-term and high-cost problems such as demolition and reconstruction or reinforcement of old bridges and culverts can be avoided, thereby greatly improving transportation efficiency.

[0003] At present, the main components of mature prefabricated bridges are usually processed with steel. Although the bearing capacity of the bridge is guaranteed, the heavy weight of the bridge body makes assembly and transportation more difficult. In addition, the existing prefabricated bridges usually use C-D joints or single and double ears in the connection of components. In addition to C and D joints, the connection parts required for the C-D joint connection method also include the C-D joint connection seat, bolt assembly and top block at the end of the bridge span. Therefore, the connection parts required for the C-D joint are not only large in number but also high in manufacturing cost. Although the single and double ears connection method has a simple structure, one connection part requires a corresponding bolt, and there is also a defect of many connection parts, which will inevitably reduce the erection speed of the prefabricated bridge. Summary of the invention

[0004] In view of this, the present invention provides a variable thickness prefabricated structure that can be quickly erected across an old culvert, which utilizes variable cross-section bearing plates to be assembled and connected through mid-span pins to form a combined load-bearing high-strength aluminum alloy bridge span bearing structure. The structure has the characteristics of ultra-light weight, fast erection speed and strong load-bearing capacity.

[0005] A variable thickness assembled structure for quickly erecting across an old culvert, comprising a left bearing plate, a right bearing plate, a support pad, a pin and a bolt; the left and right bearing plates and the support pad are all made of high-strength aluminum alloy 7075 material;

[0006] The left and right side bearing plates are arranged in a wedge shape along the longitudinal direction, and a clamping groove formed together with the bearing plates is provided at the middle and lower edges of the mid-span position, and the left and right sides are arranged in a staggered manner;

[0007] After the card slots of the left and right side bearing plates are inserted into place, they are connected by pins to form a pre-arch of a certain height. A support pad is provided at the bottom of the other end of the left and right side bearing plates, and the left and right side bearing plates are fixedly connected to the support pad by bolts.

[0008] Furthermore, the size of the wedge-shaped small ends of the left and right side bearing plates is 30 mm.

[0009] Furthermore, the interior of the left and right side bearing plates is configured as a multi-chamber structure.

[0010] Furthermore, the slot bottom plates of the left and right side bearing plates have a certain width. When subjected to heavy load deflection, the slot bottom plates serve as intermediate supports in contact with the old bridge deck thereunder.

[0011] Furthermore, when installing the left and right side bearing plates, an installation cushion is set in the middle of the span, and the installation cushion is removed after the installation is completed.

[0012] Beneficial effects:

[0013] 1. The prefabricated structure of the present invention is connected by staggered slots located at the lower edges of the mid-span of the left and right bearing plates through pins, forming a coupled force mode in which the upper edge of the mid-span section is in contact and compressed, and the lower edge is sheared, stretched and compressed by the slot 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 light weight, high strength and high hardness. The overall self-weight of the prefabricated bearing structure is light and the bearing capacity is strong.

[0014] 2. The left and right side load-bearing plates of the present invention are longitudinally arranged in a wedge shape, and the end size thereof is only 30 mm, which can minimize the height of the misalignment between the end of the bridge span plate and the original bridge deck, so that vehicles will not experience uneven driving due to excessive misalignment when passing on the bridge span plate, thereby eliminating the need to set up approach plates, making the assembled bridge span structure more concise.

[0015] 3. The overall structure of the present invention weighs 295kg, and the heaviest structural unit is the load-bearing plate, which is only 180kg. The overall structure is easy to carry and simple to install. With the cooperation of four people, the installation work can be completed within five minutes.

[0016] 4. The bottom plate of the bearing plate slot of the present invention has a certain width. When subjected to heavy load deflection, it can serve as an intermediate support in contact with the old bridge deck below it, thereby exerting the effect of joint bearing of the old bridge and the bearing plate, so that the assembled structure has two bearing modes: independent bearing of the new bridge span and coupled bearing of the new and old bridge spans. Both bearing modes meet the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a vertical layout diagram of a variable thickness prefabricated structure for quickly erecting a structure across an old culvert according to the present invention;

[0018] Figure 2 The plan layout of the variable thickness assembled structure for quickly erecting across the old culvert according to the present invention;

[0019] Figure 3 This is the elevation drawing of the load-bearing plate;

[0020] Figure 4This is the detailed elevation view of the connection part of the load-bearing plate;

[0021] Figure 5 It is the plan view of the left and right load-bearing plates;

[0022] Figure 6 It is a three-dimensional schematic diagram of the left load-bearing plate;

[0023] Figure 7 A three-dimensional diagram of the right side load-bearing plate;

[0024] Figure 8 Cross-section of the load-bearing plate;

[0025] Fig. 9 This is a schematic diagram of the location of the pillow for installation;

[0026] Fig.10 This is the plan view of the support pad.

[0027] Among them, 1-left side bearing plate, 2-right side bearing plate, 3-support pad, 4-pin rod, 5-bolt, 6-installation cushion. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0029] Take the 4m span prefabricated structure which can span most of the cover culverts and circular culverts as an example. Figure 1 As shown, the floor plan is shown in Figure 2 The assembled structure of the present invention is composed of six parts: a left-side bearing plate 1, a right-side bearing plate 2, a pin 4, a support pad 3, a bolt 5 and a mounting cushion 6.

[0030] The vertical dimensions of the left and right load-bearing plates are shown in Figure 3 For details, see Figure 4 As shown, the plane Figure 5 shown.

[0031] The left and right side bearing plates and the support pads are made of high-strength aluminum alloy 7075. The left and right bearing plates are provided with a slot formed together with the bearing plates at the middle and lower edges of the mid-span position. The left and right bearing plates are arranged alternately. After being installed in place on site, they are connected by pins 4. The three-dimensional schematic diagram is shown in Figure 6 , Figure 7 The bearing plate shown is set in a wedge shape along the longitudinal direction, and its end size is only 30mm. The main purpose is to minimize the height of the misalignment between the end of the bearing plate and the original bridge deck, so that vehicles will not be uneven when passing on the bearing plate due to excessive misalignment, thereby eliminating the need to set up approach plates, making the assembled bridge span structure simpler. In order to further reduce the deadweight of the bearing plate, its interior is set as a multi-chamber structure, and its cross-sectional schematic diagram is shown in Figure 8 shown.

[0032] The bottom plate width of the bearing plate slot is 78mm. When subjected to heavy load deflection, it can serve as an intermediate support in contact with the old bridge deck below, thereby exerting the joint bearing effect of the old bridge and the bearing plate.

[0033] In addition, when installing the bearing plate, due to the 80mm pre-camber, a mounting cushion 6 is set in the middle of the span and removed after installation. Fig. 9 The mounting cushion 6 can be made of a light wood structure with a width of 100 mm, a height of 60 mm and a length of 600 mm.

[0034] The pin rod 4 is a high-strength aluminum alloy rod with a diameter of 35 mm, and the support pad 3 is a high-strength aluminum alloy plate with a width of 300 mm, a thickness of 20 mm, and a length of 3100 mm. Fig.10 As shown, the support pad 3 is connected to the left supporting plate 1 and the right supporting plate 2 via bolts 5 .

[0035] The quality statistics of the full-bridge structural unit are shown in Table 1.

[0036] Table 1 Statistics of the quality of all bridge components

[0037]

[0038] In addition, since the bearing plate, pin rod 4, support pad 3 and bolt 5 are made of aviation aluminum alloy 7075, the emergence of aviation aluminum alloy 7075 provides a high-quality material choice for quickly erected prefabricated bridges. This material has the comprehensive advantages of light weight, high strength and high hardness. The performance comparison between it and steel and ordinary aluminum alloy is shown in Table 2.

[0039] Table 2 Material performance comparison table

[0040]

[0041] The block unit is used to analyze the bearing capacity of a 1m wide single plate strip, and the physical and mechanical indicators of the model are shown in Table 3. The live load adopts the vehicle load, and three arrangements are considered, corresponding to the most unfavorable in the span, the most unfavorable at L / 4, and the most unfavorable at the support. It is the most unfavorable distribution of two wheel pressures with a longitudinal spacing of 1.4m on the one side of the two 140kN rear axles in the vehicle load, and its action area is 200mm×600mm. The boundary conditions of the model are fixed constraints at the bottom of the support pad, the top surface of the support pad and the bottom surface of the bearing plate, as well as the mid-span contact surface of the left and right bearing plates, the pin rod slot and the pin rod, and the pin rod slot are all in contact.

[0042] Table 3 Physical and mechanical indexes of bridge span materials

[0043]

[0044] According to the Mises stress cloud diagram of the whole structure under the most unfavorable wheel load in the span, the vertical displacement cloud diagram, and the Mises stress cloud diagram of the left and right bearing plates, it can be seen that the maximum Mises stress appears on the pin rod slot of the left bearing plate, which is 321MPa. The maximum Mises stress of the right bearing plate is 281MPa, which also corresponds to the pin rod slot position. The maximum vertical displacement of the structure in the mid-span is 80.4mm. In the Mises stress cloud diagram of the pin rod, the corresponding maximum Mises stress is 244Mpa. In the contact surface compressive stress cloud diagram of the end face of the bearing plate, the contact surface is concentrated in the top 10mm range, and the maximum contact compressive stress is 134MPa. In the Mises stress cloud diagram of the support pad, the maximum stress corresponds to 67.0MPa. In the case of the least load in the span, the maximum vertical displacement of the structure in the mid-span is 80.4mm, while the distance between the bottom plate of the slot located in the mid-span of the bearing plate and the bridge deck is 80mm pre-camber plus 20mm support pad-the size of the slot protruding from the bottom edge of the mid-span section is 35mm, which is 65mm, less than the vertical displacement of 80.4mm. In fact, the slot support has come into contact with the top plate of the old bridge deck, and a joint load-bearing mode has appeared. In order to establish a coupled model of the new and old bridge spans, the combined stress and deformation behavior of the structure is examined. The model is established, and the boundary conditions of the model are that the two ends of the old bridge are simply supported, the support pad of the new bridge is fixedly connected to the top surface of the old bridge, the bottom surface of the slot of the new bridge is in contact with the bridge deck of the old bridge, and other contact relationships are the same as before.

[0045] It can be seen from the Mises stress cloud map of the left and right load-bearing plates that the Mises peak stress is 264.9MPa, which is 17.4% lower than the load-bearing plate alone. It can be seen from the vertical displacement cloud map of the new and old bridge spans that the maximum vertical displacement of the structure is 69.1mm, which is 14% lower than the load-bearing plate alone. It can be seen from the vertical displacement cloud map of the old bridge that its vertical displacement is 0.94mm. In the compressive stress cloud map at the contact point between the new and old bridge spans, the extreme value is 1.34MPa. The compressive stress integration of this area shows that the resultant force of the contact area is 60714N, that is, the new bridge span load-bearing plate transmits a vertical force of about 6 tons to the old bridge span plate, which is 34% lower than the bending moment caused by the direct action of the wheel load on the old bridge. The effect is very obvious.

[0046] It can be seen that the variable-section bearing plate with a span of 4m can meet the vehicle load and highway Class II load requirements, the maximum stress can be controlled within 321MPa, and the maximum vertical deflection can be controlled within 80.4mm; under the most unfavorable load in the span, the first-order buckling stability coefficient of the structure is 13.170, and there is no problem with the overall and local stability of the structure.

[0047] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A variable thickness prefabricated structure for rapid erection across an old culvert, characterized in that: It includes a left-side bearing plate, a right-side bearing plate, a support pad, a pin and a bolt; the left and right-side bearing plates and the support pad are all made of high-strength aluminum alloy 7075 material; The left and right side bearing plates are arranged in a wedge shape in the longitudinal direction, and a clamping groove formed together with the bearing plates is provided at the middle and lower edges of the mid-span position, and the left and right sides are arranged in a staggered manner; After the card slots of the left and right side bearing plates are inserted into place, they are connected by pins to form a pre-arch of a certain height. A support pad is provided at the bottom of the other end of the left and right side bearing plates, and the left and right side bearing plates are fixedly connected to the support pad by bolts.

2. A variable thickness assembled structure for rapid erection across an old culvert as claimed in claim 1, characterized in that: The size of the wedge-shaped small ends of the left and right side bearing plates is 30 mm.

3. A variable thickness assembled structure for rapid erection across an old culvert as claimed in claim 2, characterized in that: The left and right side bearing plates are internally arranged with a multi-chamber structure.

4. A variable thickness assembled structure for rapid erection across an old culvert as claimed in claim 3, characterized in that: The slot bottom plates of the left and right side bearing plates have a certain width. When subjected to heavy load deflection, the slot bottom plates serve as intermediate supports in contact with the old bridge deck thereunder.

5. A variable thickness assembled structure for rapid erection across an old culvert as claimed in claim 3 or 4, characterized in that: When installing the left and right side bearing plates, set installation pads in the middle of the span and remove them after installation.

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