A short cantilever simply supported rigid frame bridge with tie rods and construction method

Abstract

The invention relates to a short cantilever simply supported rigid frame bridge with a tie rod and a construction method, comprising an abutment, an abutment leg, a variable height beam, a short cantilever beam and a prestressed tie rod; the abutment leg is assembled on the abutment, the variable height beam is supported on the abutment leg, and the beam height of the variable height beam gradually decreases from the support point to the middle of the span; the short cantilever beam is connected to the variable height beam; the prestressed tie rod connects the short cantilever beam and the abutment; the invention is suitable for crossing roads, rivers and canyons, where a single-span bridge is required due to limited terrain; the invention can achieve a single-span crossing without dropping piers.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction engineering structures, and in particular relates to a short cantilever simply supported rigid frame bridge with a tie rod and a construction method. Background Art

[0002] Variable-height beam bridges with high fulcrum beams and low mid-span beams are widely used in bridges across highways, rivers and canyons due to their beautiful and simple lines and cantilever casting without support construction methods. At present, variable-height beam bridges include cantilever cast rigid frame bridges and cantilever cast continuous beam bridges, which adopt multi-span structures and require the side-to-mid span ratio to be no less than 0.5. Therefore, in some special terrains, they cannot be used because the side spans cannot be arranged or are too small.

[0003] If the beam height of a simply supported beam bridge or a simply supported rigid frame bridge is high at the support point and low in the mid-span, the section stiffness and the bending moment are inconsistent, and the mid-span section cannot meet the force requirements. In addition, it is necessary to set up a support for construction, and the cantilever casting method cannot be used for construction, which is inconvenient.

[0004] In view of the above problems, it is necessary to improve them. Summary of the invention

[0005] The present invention aims to overcome the defects in the above-mentioned prior art and provides a short cantilever simply supported rigid frame bridge with tie rods; the bridge has beautiful shape, simple structure, safe structure, convenient construction, can realize a single-span structure with variable height beam, and can be constructed by cantilever casting method.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is: a short cantilever simply supported rigid frame bridge with tension rods, including abutments, abutment legs, variable height beams, short cantilever beams and prestressed tension rods; the abutment legs are assembled on the abutments, the variable height beams are supported on the abutment legs, and the beam height of the variable height beams gradually decreases from the fulcrum to the mid-span; the short cantilever beams are connected to the variable height beams; the prestressed tension rods connect the short cantilever beams and the abutments.

[0007] As a preferred solution of the present invention, the abutment adopts a pile foundation or an expanded foundation.

[0008] As a preferred solution of the present invention, the change in beam height of the variable height beam adopts linear change, parabolic change, high-order parabolic change, catenary change or circular arc change.

[0009] As a preferred solution of the present invention, the abutment legs are inclined toward the mid-span according to the stress conditions, and the vertical angle can be adjusted.

[0010] As a preferred solution of the present invention, the prestressed tie rod is inclined toward the rear side of the abutment according to the stress conditions, and the vertical angle can be adjusted.

[0011] As a preferred solution of the present invention, the prestressed tension of the prestressed tie rod is adjusted to adjust the internal force of the variable height beam and the short cantilever beam so that the bridge meets the force requirements.

[0012] As a preferred solution of the present invention, the variable height beam and the short cantilever beam are provided with longitudinal prestressed steel strands, and the longitudinal prestress is anchored and tensioned at the tail section of the short cantilever beam.

[0013] As a preferred solution of the present invention, the short cantilever beam is provided with a vertical prestressed steel strand to improve the shear resistance of the short cantilever beam.

[0014] A construction method for a short cantilever simply supported rigid frame bridge with a tie rod comprises the following steps:

[0015] Step A: construct the abutment foundation; during the construction of the abutment foundation, embed the tensile anchor device, set up the support frame on site, and cast the abutment legs;

[0016] Step B: construct the short cantilever main beam; set up the support on site and cast the short cantilever main beam; during casting, embed the tensile anchor device at the end of the cantilever beam; after casting, apply longitudinal and vertical prestressed tendons to the short cantilever beam to improve the integrity and shear resistance of the cantilever beam;

[0017] Step C: Install the prestressed tie rod; connect the end of the short cantilever main beam with the abutment foundation, and transmit the tension to the abutment foundation through the tie rod; the prestressed tie rod is constructed strictly according to the design, and the prestressed tie rod is protected at multiple levels;

[0018] Step D: Construct the variable height beam; Use the cantilever casting method to construct the variable height beam and close it at the mid-span. During the construction process, adjust the tension of the prestressed tie rods in stages to ensure safety during the construction process;

[0019] Step E: Construction of bridge deck system and ancillary facilities;

[0020] Step F: Adjust the tension of the prestressed tie rod; adjust the tension of the tie rod to the design value at the bridge completion stage according to the stress conditions of the short cantilever main beam and the variable height beam.

[0021] The beneficial effects of the present invention are:

[0022] 1. Applicability of single-span bridges: The present invention is suitable for crossing roads, rivers and canyons, where a single-span bridge is required due to terrain restrictions. The present invention can achieve a single-span crossing without the need for piers.

[0023] 2. Convenient and fast construction: The present invention can be constructed by suspended pouring method, and no support is required for construction, which solves the technical problem of difficulty in setting up support when crossing roads, rivers and canyons, and the construction is convenient and fast;

[0024] 3. Strong spanning capacity of the bridge: The present invention sets a prestressed tie rod on the short cantilever, and the internal force of the bridge can be adjusted by adjusting the size of the prestress, thereby increasing the spanning capacity;

[0025] 4. Good economy: The present invention adopts a simply supported structure, which can eliminate the side span of conventional cantilever rigid frame bridge or cantilever continuous beam bridge, reduce the scale of the bridge, and save engineering cost;

[0026] 5. Beautiful shape: The present invention maintains the beautiful characteristics of the variable height beam bridge, with high beams at the fulcrums and low beams in the middle of the span, and a simple and beautiful line shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a side view of a short cantilever simply supported rigid frame bridge with a tie rod according to an embodiment of the present invention;

[0028] Figure 2 It is a top view of a short cantilever simply supported rigid frame bridge with tie rods according to an embodiment of the present invention;

[0029] Figure 3 It is an AA cross-sectional view of an embodiment of the present invention;

[0030] Reference numerals in the figure: short cantilever beam 101 , variable height beam 102 , abutment legs 103 , prestressed tie rods 104 , abutment 105 . DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Example:

[0034] like Figure 1-3As shown, the present embodiment provides a short cantilever simply supported rigid frame bridge with tension rods, comprising abutments 105, abutment legs 103, variable height beams 102, short cantilever beams 101 and prestressed tension rods 104; as can be seen from the figure, abutments 105 are arranged on the original ground, wherein the abutments 105 adopt pile foundations or expanded foundations; the abutment legs 103 are supported on the abutments 105, and the short cantilever beams 101 and variable height beams 102 are supported on the abutment legs 103; the abutment legs 103 are inclined toward the mid-span according to the stress conditions, and the vertical angle can be adjusted; the variable height beams 102 and the short cantilever beams 101 are provided with longitudinal prestressed steel strands, and the longitudinal prestress is anchored and tensioned at the tail section of the short cantilever beam; applicability of the single-span bridge of the present invention: the present invention is suitable for crossing roads, rivers and canyons, where single-span bridges are required due to limited terrain; the present invention can achieve a single-span crossing without dropping piers.

[0035] The beam height of the variable height beam 102 gradually decreases from the support point to the mid-span; the beam height of the variable height beam 102 changes by linear change, parabolic change, high-order parabolic change, catenary change or circular arc change; the economic efficiency of the present invention is good: the present invention adopts a simply supported structure, which can eliminate the side span of a conventional cantilever rigid frame bridge or a cantilever continuous beam bridge, reduce the scale of the bridge, and save engineering costs.

[0036] The short cantilever beam 101 is connected to the variable height beam 102; the prestressed tie rod 104 connects the short cantilever beam 101 and the abutment 105; the short cantilever beam 101 is provided with a vertical prestressed steel bundle to improve the shear resistance of the short cantilever beam; wherein, the construction of the present invention is convenient and fast: the present invention can adopt the suspended casting method for construction, and no scaffolding is required for construction, which solves the technical problem of difficulty in scaffolding when crossing roads, rivers, and canyons, and the construction is convenient and fast.

[0037] The prestressed tie rod 104 connects the tail end of the abutment leg 103 and the foundation of the abutment 105; the prestressed tie rod 104 is inclined toward the tail side of the abutment according to the stress condition, and the vertical angle can be adjusted; by tensioning the prestressed tie rod 104, the internal force of the short cantilever beam 101 and the variable height beam 102 can be adjusted to ensure that the structure meets the stress requirements; the bridge of the present invention has a strong spanning capacity: the present invention sets a prestressed tie rod for the short cantilever, and the internal force of the bridge can be adjusted by adjusting the size of the prestress, thereby increasing the spanning capacity;

[0038] The actual construction process of a short cantilever simply supported rigid frame bridge with tie rods includes the following steps:

[0039] Step A, constructing the foundation of the abutment 105; during the construction of the foundation of the abutment 105, a tensile anchor device is pre-buried, a support is set up on site, and the abutment legs 103 are cast;

[0040] Step B, constructing the short cantilever main beam 101; setting up a support on site and casting the short cantilever main beam 101. During casting, a tensile anchoring device is pre-embedded at the end of the cantilever beam. After casting, longitudinal and vertical prestressed tendons are applied to the short cantilever beam to improve the integrity and shear resistance of the cantilever beam.

[0041] Step C, installing the prestressed tie rod 104. The prestressed tie rod 104 is connected to the end of the short cantilever main beam and the abutment foundation, and the tension is transmitted to the abutment foundation through the tie rod. The prestressed tie rod 104 is constructed strictly according to the design, and the prestressed tie rod 104 is protected at multiple levels.

[0042] Step D, constructing the variable height beam 102. The variable height beam 102 is constructed by cantilever casting method and closed at the mid-span. During the construction process, the tension of the prestressed tie rod 104 is adjusted in stages to ensure safety during the construction process.

[0043] Step E: Construction of bridge deck system and ancillary facilities.

[0044] Step F, adjusting the tension of the prestressed tie rod 104. According to the stress conditions of the short cantilever main beam and the variable height beam, the tension of the tie rod is adjusted to the design value of the bridge completion stage.

[0045] The present invention is suitable for terrains where a variable height beam single spans across roads, rivers or canyons, and can effectively solve the stress and construction problems of a large-span single-span variable height beam. The present invention has an aesthetically pleasing shape: the present invention maintains the aesthetic characteristics of a variable height beam bridge, with a high beam at the fulcrum, a low beam in the middle of the span, and a simple and beautiful line shape.

[0046] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention; therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0047] Although the following terms are often used in this paper: short cantilever beam 101, variable height beam 102, abutment leg 103, prestressed tie rod 104, abutment 105, etc., the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A short cantilever simply supported rigid frame bridge with tie rods, characterized in that: The invention comprises an abutment (105), an abutment leg (103), a variable height beam (102), a short cantilever beam (101) and a prestressed tie rod (104); the abutment leg (103) is assembled on the abutment (105), the variable height beam (102) is supported on the abutment leg (103), and the beam height of the variable height beam (102) gradually decreases from the support point to the mid-span; the short cantilever beam (101) is connected to the variable height beam (102); the prestressed tie rod (104) The stress tie rod (104) connects the short cantilever beam (101) and the abutment (105); the prestressed tie rod (104) is inclined toward the rear side of the abutment according to the stress conditions, and the vertical angle can be adjusted; the prestressed tension of the prestressed tie rod (104) is adjusted to adjust the internal forces of the variable height beam and the short cantilever beam so that the bridge meets the stress requirements; the prestressed tie rod (104) connects the rear end of the abutment leg (103) and the foundation of the abutment (105).

2. A short cantilever simply supported rigid frame bridge with tie rods according to claim 1, characterized in that: The abutment (105) adopts a pile foundation or an expanded foundation.

3. The short cantilever simply supported rigid frame bridge with tie rods according to claim 1, characterized in that: The change in beam height of the variable height beam (102) adopts linear change, parabola change, high-order parabola change, catenary change or circular arc change.

4. The short cantilever simply supported rigid frame bridge with tie rods according to claim 1, characterized in that: The abutment legs (103) are inclined toward the mid-span according to the stress conditions, and the vertical angle can be adjusted.

5. A short cantilever simply supported rigid frame bridge with tie rods according to claim 1 or 3, characterized in that: The variable height beam (102) and the short cantilever beam (101) are provided with longitudinal prestressed steel strands, and the longitudinal prestressing force is anchored and tensioned at the tail section of the short cantilever beam.

6. The short cantilever simply supported rigid frame bridge with tie rods according to claim 5, characterized in that: The short cantilever beam (101) is provided with a vertical prestressed steel strand to improve the shear resistance of the short cantilever beam.

7. A construction method for a short cantilever simply supported rigid frame bridge with tie rods according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step A: constructing the foundation of the abutment (105); during the construction of the abutment foundation, a tensile anchor device is pre-buried, a support is set up on site, and the abutment legs (103) are cast; Step B: constructing a short cantilever main beam (101); setting up a support on site and casting the short cantilever main beam (101); during casting, pre-embedding a tensile anchor device at the end of the cantilever beam; after casting, applying longitudinal and vertical prestressed tendons to the short cantilever beam to improve the integrity and shear resistance of the cantilever beam; Step C: installing the prestressed tie rod (104); connecting the prestressed tie rod (104) to the end of the short cantilever main beam and the abutment foundation, and transmitting the tension to the abutment foundation through the tie rod; the prestressed tie rod (104) is constructed strictly according to the design, and the prestressed tie rod (104) is protected at multiple levels; Step D: constructing the variable height beam (102); using the cantilever casting method to construct the variable height beam (102), closing it at the mid-span; during the construction process, adjusting the tension of the prestressed tie rod (104) in stages to ensure safety during the construction process; Step E: Construction of bridge deck system and ancillary facilities; Step F: adjusting the tension of the prestressed tie rod (104); adjusting the tension of the tie rod to the design value at the bridge completion stage according to the stress conditions of the short cantilever main beam and the variable height beam.

Images