Pier column slimmed steel truss landscape bridge and construction method thereof

Abstract

The invention provides a pier stud slim steel truss landscape bridge and a construction method thereof.The pier stud slim steel truss landscape bridge comprises a steel truss, slim pier studs, pier stud foundations, bridge abutments and end supports, the steel truss is an upper structure of the bridge, the slim pier studs are steel structural members and bear tension, the upper ends of the pier stud foundations are connected with the slim pier studs, and the lower ends of the pier stud foundations are connected with the bridge abutments. The bridge abutment comprises an abutment body and a foundation of the abutment body, and the end supports are connecting supports between the two ends of the steel truss and the bridge abutment body. Before the slim pier column is installed, a temporary ballasting load larger than the second-stage dead load and the use live load of the bridge is applied to the steel truss behind the falling frame, and after the slim pier column is installed, the temporary ballasting load is removed. The pier column bears tension all the time in the using process of the bridge, the problem that the pier column is pressed to be unstable is solved, a high-strength steel structure component can be adopted, the pier column is thinned, the bridge landscape effect is improved, the utilization rate of the steel truss steel strength can be remarkably increased, and material waste is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction engineering, and in particular to a steel truss landscape bridge with slender piers and a construction method thereof. Background Art

[0002] With the continuous development of social economy and the continuous improvement of the public's aesthetic level, people's demand for bridge structures is no longer limited to meeting transportation functions, and the pursuit of the landscape of bridge architectural shapes is also getting higher and higher.

[0003] Steel truss bridges have become the preferred bridge type for urban landscape bridges due to their lightweight structure, fast construction, and modern design. As the main load-bearing member, steel trusses must have sufficient strength and rigidity during bridge construction and design. Due to the characteristics of light weight and high strength of steel structures, the rigidity of steel trusses is usually controlled during design, while their strength is often in surplus. The strength of steel is not fully utilized, resulting in a waste of materials. In addition, when the bridge is long, it is generally necessary to add piers to support the beam in order to reduce the span and meet the rigidity requirements of the beam. The piers of existing steel truss bridges are designed as compression members. Since they must meet the requirements of both strength and stability, their cross-sectional dimensions are often relatively large, such as Figure 1 and Figure 2 As shown, the landscape effect of the steel truss bridge is affected. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a steel truss landscape bridge with slender piers and a construction method thereof to solve the problems raised in the above background technology.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A steel truss landscape bridge with slender piers, comprising a steel truss, a slender pier, a pier foundation, an abutment and an end support, wherein the steel truss is the upper structure of the bridge, the slender pier is a steel structural member and bears tension, is arranged between two abutments, and the upper end is connected to the bottom of the node between the steel truss web and the lower chord, the upper end of the pier foundation is connected to the slender pier, the abutment comprises an abutment body and its foundation, the end support is a connecting support between the two ends of the steel truss and the abutment, and the two ends of the steel truss are connected to the upper end of the abutment body of the abutment through the end support.

[0006] Furthermore, the slenderized piers are columnar piers or V-shaped piers, and one or at least two are arranged in the transverse direction of the bridge.

[0007] Furthermore, the slenderized pier is rigidly connected or hingedly connected to the steel truss and the pier foundation.

[0008] Furthermore, one or at least two slenderized piers are arranged along the bridge direction.

[0009] The method for constructing the steel truss landscape bridge with slender piers of the present invention has the following specific construction methods: Construction phase 1: Construction of pier foundations and abutments, and installation of end supports on the top surface of the abutment; Construction stage 2: The factory processes and manufactures steel trusses in segments according to the linear shape taking into account the pre-camber, transports them to the site, and erects them on temporary piers. Then, the connection between the steel truss segments and the connection between the steel truss and the end supports are completed; Construction stage 3: Remove the temporary supports, then apply a temporary compressive load greater than the second-phase dead load and live load of the bridge to the steel truss, causing the steel truss to undergo downward vertical elastic deformation; Construction phase 4: Install the slimmed-down piers and complete the connection between the slimmed-down piers, steel trusses and pier foundations; Construction Phase 5: Remove the temporary compressive load applied to the steel truss. At this time, the slenderized piers generate tension due to limiting the upward recovery of the elastic deformation of the steel truss. This tension is greater than the pressure generated by the slenderized piers under the second-phase dead load of the bridge and the live load. After that, the construction of the bridge's ancillary facilities is carried out to complete the construction of the bridge.

[0010] Compared with the prior art, the present invention has the following beneficial effects: 1. The piers in the steel truss landscape bridge constructed by the present invention bear tensile force and do not have the problem of instability under compression. High-strength steel structural components can be used to achieve the slenderization of the piers and improve the landscape effect of the bridge.

[0011] 2. When the landscape bridge of the present invention is used under live load, the slender piers can serve as supports for the steel trusses just like the traditional compression piers, thus reducing the span of the steel trusses and making the rigidity of the steel trusses meet the requirements of the specifications.

[0012] 3. Before the installation of the slenderized piers, the landscape bridge of the present invention can significantly improve the utilization rate of the steel strength of the steel truss and reduce material waste by applying a temporary ballast load greater than the second-phase dead load and the live load of the bridge to the steel truss after the frame is dropped. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structural system of a steel truss bridge in the prior art; Figure 2 It is a schematic cross-sectional view of a pier of a steel truss bridge in the prior art; Figure 3 It is a schematic diagram of the structural system of the steel truss landscape bridge of the present invention; Figure 4 It is a schematic cross-sectional view of the steel truss landscape bridge column type pier of the present invention; Figure 5 It is a schematic cross-sectional view of a V-shaped pier column of a steel truss landscape bridge of the present invention; Figure 6 The figure is a schematic diagram of the construction process of the steel truss landscape bridge of the present invention.

[0014] Marked in the figure are: 1. Steel truss; 2. Slenderized pier; 3. Pier foundation; 4. Abutment; 5. End support. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments: The present invention provides a steel truss landscape bridge with slimmed-down piers and a construction method thereof, which can achieve slimming of the piers, improve the landscape effect of the bridge, and significantly improve the utilization rate of the steel strength of the steel truss, thereby reducing material waste.

[0016] The structural system of the steel truss landscape bridge of the present invention is as follows Figure 3 As shown, it includes a steel truss 1, a slenderized pier 2, a pier foundation 3, an abutment 4 and an end support 5. The steel truss 1 is the upper structure of the bridge. The slenderized pier 2 is a steel structural member and bears tension. It is arranged between two abutments, and its upper end is connected to the bottom of the node between the steel truss web and the lower chord. The upper end of the pier foundation 3 is connected to the slenderized pier. The abutment 4 includes an abutment body and its foundation. The end support 5 is a connecting support between the two ends of the steel truss and the abutment. The two ends of the steel truss 1 are connected to the upper end of the abutment body of the abutment 4 through the end support 5.

[0017] Furthermore, the slim pier 2 is a columnar pier or a V-shaped pier, and one or at least two are arranged in the transverse direction of the bridge.

[0018] Furthermore, the slenderized pier 2 is rigidly connected or hingedly connected to the steel truss 1 and the pier foundation 3 .

[0019] Furthermore, one or at least two slimmed-down piers 2 are provided along the bridge direction.

[0020] The present invention provides a method for constructing a steel truss landscape bridge with slender piers, characterized in that the specific steps are as follows: Construction stage 1: constructing the pier foundation 3 and the abutment 4, and installing the end support 5 on the top surface of the abutment 4; Construction stage 2: The factory processes and manufactures the steel truss 1 in segments according to the linear shape taking into account the pre-camber, transports it to the site, and erects it on the temporary piers, and then completes the connection between the segments of the steel truss 1 and the connection between the steel truss 1 and the end support 5; Construction stage 3: Remove the temporary support, then apply a temporary compressive load greater than the second phase dead load and live load of the bridge to the steel truss 1, causing the steel truss 1 to undergo downward vertical elastic deformation; Construction stage 4: installing the slenderized pier 2 and completing the connection between the slenderized pier 2, the steel truss 1 and the pier foundation 3; Construction stage 5: The temporary compressive load applied to the steel truss 1 is removed. At this time, the slender pier 2 generates tension due to limiting the upward recovery of the elastic deformation of the steel truss 1. The tension is greater than the pressure generated by the slender pier 2 under the second-phase dead load of the bridge and the live load. After that, the construction of the bridge ancillary facilities is carried out to complete the construction of the bridge.

[0021] The present invention is further described in detail below by taking actual engineering as an example.

[0022] This embodiment is a two-span steel truss pedestrian bridge with a span of (35+35)m, a total width of 4.8m, a double-column pier with a height of 5m, a triangular truss with a truss height of 3.5m, a section spacing of 7m, and a truss spacing of 4.5m. The steel truss is made of Q355C steel, the upper and lower chords are both 500×300×20mm box sections, and the web members are 250×250×16mm box sections.

[0023] according to Figure 1 and Figure 2 When the existing technology is used for design, the calculation results show that the vertical first-order natural frequency of the steel truss is 6.12 Hz, which meets the design specification requirement of not less than 3 Hz (if no intermediate pier is set, the vertical first-order natural frequency of the steel truss is 1.73 Hz, which does not meet the design specification requirement of not less than 3 Hz); the maximum stress of the steel truss is 68.5 MPa, and the material strength utilization rate is only 24.9%; the maximum vertical reaction force of a single pier in the transverse direction of the bridge is 1142 kN, and the pier is subjected to a large vertical pressure. The pier adopts a concrete circular cross-section pier with a diameter of about 600 mm to meet the force requirements. At this time, the aspect ratio of the pier is 8.33.

[0024] according to Figure 3 , Figure 4 and Figure 6The technology of the present invention is used for design. The pier column uses two solid steel bars with a diameter of 60mm. The calculation results show that the vertical first-order natural frequency of the steel truss is 6.04Hz, which is very small compared with the design results of the prior art and meets the design specification requirement of not less than 3Hz; the maximum stress of the steel truss during construction is 199.3MPa, the maximum stress in the bridge state is 194.3MPa, and the maximum stress in the use state is 225.4MPa, and the material strength utilization rate is increased to about 83.5%; the maximum tension during the construction of a single pier column is 795kN, and the stress is 281.0MPa. The strength of 40Cr high-strength alloy steel meets the requirements; the tension of a single pier column in the bridge state is 621kN in the transverse direction, and the minimum tension in the use state is 226kN, and the maximum tension in the use state is less than the maximum tension during construction. The pier column is always under tension during the use of the bridge, and there is no instability problem. At this time, the aspect ratio of the pier is 83.3, which is 10 times that of the pier in the prior art, thus achieving the slenderization of the pier.

[0025] The above description is only a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent change made based on the technical essence of the present invention still falls within the scope of protection required by the present invention.

Claims

1. A steel truss landscape bridge with slenderized piers, comprising a steel truss (1), slenderized piers (2), pier foundations (3), abutments (4) and end supports (5), characterized in that: The steel truss (1) is the upper structure of the bridge. The slenderized pier (2) is a steel structural member that bears tension and is arranged between two abutments (4). The upper end of the slenderized pier (2) is connected to the bottom of the node between the web and the lower chord of the steel truss (1). The upper end of the pier foundation (3) is connected to the slenderized pier (2). The abutment (4) includes an abutment body and a foundation thereof. The end support (5) is a connecting support between the two ends of the steel truss (1) and the abutment (4). The two ends of the steel truss (1) are connected to the upper end of the abutment body of the abutment (4) through the end support (5).

2. The steel truss landscape bridge with slim piers according to claim 1, characterized in that: The slenderized piers (2) are columnar piers or V-shaped piers, and one or at least two are arranged in the transverse direction of the bridge.

3. A steel truss landscape bridge with slim piers according to claims 1 and 2, characterized in that: The slenderized pier column (2) is rigidly connected or hingedly connected to the steel truss (1) and the pier column foundation (3).

4. The steel truss landscape bridge with slim piers according to claims 1 and 2, characterized in that: One or at least two of the slenderized piers (2) are arranged along the bridge direction.

5. The method for constructing a steel truss landscape bridge with slimmed-down piers according to any one of claims 1 to 4, characterized in that: The specific construction methods are as follows: Construction stage 1: constructing the pier foundation (3) and the abutment (4), and installing the end support (5) on the top surface of the abutment (4); Construction stage 2: The factory processes and manufactures the steel truss (1) in segments according to the linear shape taking into account the pre-camber, transports it to the site, and erects it on the temporary piers, and then completes the connection between the steel truss (1) segments and the connection between the steel truss (1) and the end support (5); Construction stage 3: the temporary support is removed, and then a temporary compressive load greater than the second-stage dead load and the service live load of the bridge is applied to the steel truss (1), so that the steel truss (1) produces downward vertical elastic deformation; Construction stage 4: installing the slenderized pier column (2) and completing the connection between the slenderized pier column (2) and the steel truss (1) and the pier column foundation (3); Construction stage 5: the temporary compressive load applied to the steel truss (1) is removed. At this time, the slenderized pier (2) generates a tensile force due to the upward recovery of the elastic deformation of the steel truss (1). The tensile force is greater than the pressure generated by the slenderized pier (2) under the second-phase dead load and the live load of the bridge. After that, the construction of the bridge ancillary facilities is carried out to complete the construction of the bridge.

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