Ground stress reduction device for small agricultural bridge in plain area

Abstract

The utility model discloses a plain area small -size farm bridge foundation stress reduction device, plain area small -size farm bridge includes: abutment bottom plate, abututment, cap, bridge deck panel, pours abutment bottom plate in the abutment foundation pit, pours abutment on abutment bottom plate, pours cap on abututment, pours bridge deck panel on cap, its characterized by: increase foundation stress reduction device, the foundation stress reduction device includes: bottom plate, paving layer, pours a bottom plate in the channel bottom between two abutments, and bottom plate bar dowel inserts into both sides abutment bottom plate, and paving paving layer on bridge deck panel, and paving layer bar dowel inserts into cap. The utility model discloses simple structure, compact arrangement, saves the project investment, is applicable to small -size farm bridge, and the span is about 8 meters, and the abutment ground bearing capacity is greater than 70 kiloPascal, and it is easy to use widely.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic structures, and specifically relates to a stress reduction device for the foundation of a small agricultural bridge in a plain area. Background Technology

[0002] Rural bridges refer to bridges that span canals, rivers, etc., on rural roads, typically with a span of around 8 meters. Small rural bridges are widely used in rural water conservancy, high-standard farmland, and land reclamation projects, and are numerous and widespread.

[0003] In recent years, governments at all levels have attached great importance to water conservancy projects that benefit the people, constructing numerous small agricultural bridges as part of irrigation area water-saving renovations and high-standard farmland improvement projects. However, due to the dispersed nature of these projects and incomplete geological surveys, certain risks have been introduced to the safe operation of these agricultural bridges.

[0004] Some agricultural bridges, due to complex geological conditions and weak interlayers in their foundations, differ from the surrounding geological conditions, causing significant settlement and rendering them unsafe. Demolition and reconstruction would result in economic losses and negative social impact. Therefore, it is essential to modify the structures of these problematic agricultural bridges to meet foundation bearing capacity requirements and ensure normal use. Summary of the Invention

[0005] The purpose of this invention is to propose a stress reduction device for the foundation of small agricultural bridges in plain areas, which can be used to modify the structure of problematic agricultural bridges to meet the bearing capacity requirements of the foundation, minimize the impact on the original bridge structure and foundation settlement, meet the functional requirements of the bridge, and save investment.

[0006] The technical solution of this utility model is: a small agricultural bridge in a plain area, comprising: a bridge abutment base plate, abutment, abutment cap, and bridge deck; the bridge abutment base plate is poured in the bridge abutment foundation pit, the bridge abutment is poured on the bridge abutment base plate, the abutment cap is poured on the bridge abutment, and the bridge deck is poured on the abutment cap; its characteristic is: the addition of a foundation stress reduction device, the foundation stress reduction device comprising: a base plate and a pavement layer; a base plate is poured at the bottom of the channel between the two bridge abutments, and the base plate is reinforced with reinforcing bars inserted into the base plates of the two bridge abutments; a pavement layer is laid on the bridge deck, and the pavement layer is reinforced with reinforcing bars inserted into the abutment cap.

[0007] A further design involves driving wooden piles upstream and downstream of the abutment base.

[0008] A further design step involves casting anti-collision piers on the platform cap.

[0009] A further design step is to install load and height limit signs on the agricultural bridge.

[0010] The features of this utility model are: 1. A base slab is poured at the bottom of the channel between the two bridge abutments. The reinforcing bars are inserted into the base slabs of the two bridge abutments to form a whole base slab, which increases the stress area and reduces the base stress.

[0011] 2. A pavement layer is laid on the bridge deck, and the reinforcing bars of the pavement layer are inserted into the abutment cap to fill the vertical settlement difference, so that the bridge deck and the abutment are connected as a whole.

[0012] 3. Drive wooden piles upstream and downstream of the abutment base plate to fix the base plate and abutment and prevent lateral displacement.

[0013] 4. The structure is simple and compact, saving on engineering investment. It is suitable for small agricultural bridges with a span of about 8 meters and a foundation bearing capacity of more than 70 kPa. It is easy to promote and use. Attached Figure Description

[0014] Figure 1 Longitudinal section view of the bridge before reinforcement; Figure 2 Longitudinal section view of the reinforced bridge; Figure 3 for Figure 2 A cross-sectional view of a foundation stress reduction device; In the picture: 1 Bridge abutment base plate, 2 Bridge abutment, 3 Abutment cap, 4 Bridge deck, 5 Base plate, 6 Pavement layer, 7 Crash barrier, 8 Load limit and height limit sign. Detailed Implementation

[0015] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0016] like Figure 1 As shown, the cross-section of the bridge before reinforcement is shown. The bridge is of conventional design form with a ditch in the middle. The bridge abutment base plate 1 is poured in the bridge abutment foundation pit, the bridge abutment 2 is poured on the bridge abutment base plate 1, the abutment cap 3 is poured on the bridge abutment 2, and the bridge deck 4 is poured on the abutment cap 3.

[0017] like Figure 2 The diagram shown is a cross-sectional view of the bridge after reinforcement with a foundation stress reduction device. The foundation stress reduction device includes: a base plate 5 and a pavement layer 6; a base plate 5 is poured at the bottom of the channel between the two abutments 2, and the reinforcing bars of the base plate 5 are inserted into the base plates 1 of the abutments on both sides; a pavement layer 6 is laid on the bridge deck 4, and the reinforcing bars of the pavement layer 6 are inserted into the abutment cap 3, and the top surface of the pavement layer is at the same elevation as the bridge approach connection.

[0018] A further design involves driving wooden piles upstream and downstream of the abutment base.

[0019] A further design step is to cast anti-collision blocks 7 on the platform cap 3.

[0020] A further design step is to install load and height limit signs on the agricultural bridge.

[0021] Engineering Example: High-standard farmland improvement project in a certain district, and reinforcement of small agricultural bridges. Problem: Many bridges were newly built or demolished in the project area. Drilling was only conducted on 10-meter spans and some 8-meter spans. For the remaining bridges, construction proceeded normally if no weak soil layers were found during foundation pit excavation. One agricultural bridge in the project area had an 8-meter span and a net width of 4.5 meters. No weak soil layers were found after the abutment foundation pit was excavated, so construction proceeded normally. After the abutment, cap, and bridge deck were poured, a uniform vertical settlement of approximately 20 centimeters was observed on both sides of the abutment.

[0022] Cause Analysis: After communicating with the construction unit, it was found that the soil near the agricultural bridge was of poor quality, containing a layer of silt. Therefore, a supplementary geological survey was conducted near the bridge. The supplementary geological data showed that the soil layer at the bottom of the bridge abutment was sandy loam with an allowable bearing capacity of 110 kPa. However, a 1-meter-thick layer of silt existed 40 centimeters below the abutment foundation, with an allowable bearing capacity of only 70 kPa. Analysis indicated that the main cause of the vertical settlement on both sides of the bridge abutment was the presence of a weak interlayer in the foundation below the abutment bottom slab.

[0023] Solution: Since the bridge abutment construction has been completed, it is difficult to implement the solution of reinforcing the poor foundation to increase the bearing capacity. Therefore, the solution is to increase the bearing area and reduce the base stress. That is, to replace the existing design with a single base slab. After review, the theoretical value of the foundation stress under the existing design is 113 kPa, while the foundation stress after adopting the single base slab solution is 66 kPa. The specific reinforcement plan is as follows: ① A new base slab is poured at the bottom of the channel between the two bridge abutments, and rebar is inserted into the base slabs on both sides of the bridge abutment to form a single base slab, increasing the bearing area and reducing the base stress; ② The bridge deck pavement layer is used, and rebar is inserted into the abutment cap to fill the vertical settlement difference, so that the bridge deck and the bridge abutment are connected as a whole; ③ Wooden piles are driven upstream and downstream of the base slab to fix the base slab and the bridge abutment and prevent lateral displacement.

[0024] Implementation results: After the bridge has been in use for a period of time, the vertical settlement of the bridge abutments has stabilized according to observation.

Claims

1. Stress reduction device for foundation of small agricultural bridges in plains areas. Small agricultural bridges in plains areas include: The bridge abutment includes a base slab, an abutment, an abutment cap, and a bridge deck. The base slab is poured within the abutment foundation pit, the abutment is poured onto the base slab, an abutment cap is poured onto the abutment, and a bridge deck is poured onto the abutment cap. The feature is the addition of a foundation stress reduction device, which includes a base slab and a pavement layer. A base slab is poured at the bottom of the channel between the two abutments, and reinforcing bars are inserted into the base slabs of both abutments. A pavement layer is laid on the bridge deck, and reinforcing bars are inserted into the abutment cap.

2. The stress reduction device for small agricultural bridge foundations in plain areas according to claim 1, characterized in that: Wooden piles were driven upstream and downstream of the bridge abutment base.

3. The stress reduction device for small agricultural bridge foundations in plain areas according to claim 1, characterized in that: Anti-collision piers were poured on the top of the platform.

4. The stress reduction device for small agricultural bridge foundations in plain areas according to claim 1, characterized in that: Load and height limit signs have been installed on the agricultural bridge.

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