A variable-width variable-box asymmetric continuous rigid frame bridge and a construction method thereof

Abstract

The application discloses a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method, wherein a variable-width variable-box 'large-width horn-shaped' box girder is adopted for a side span support cast-in-situ beam section; the main span cantilever casting beam section is connected through a mid-span closure section; and the construction method is that the side span is cast in-situ by using a support, and the main span is cantilever cast by using a hanging basket. The application makes the continuous rigid frame bridge continue to be applied in the case of a small side span ratio and variable-width variable-box, and continues to play the economic and durable characteristics of the concrete bridge, so that good economic benefits can be achieved. The asymmetric construction method effectively reduces the construction risk caused by the structural asymmetry of the special rigid frame, the side span adopts the variable-width variable-box 'large-width horn-shaped' box girder, which provides a solution for balancing the self-weight of the main span and moving the unconditionally arranged flat intersection on the roadbed to the bridge, simultaneously solves the problem of the negative reaction force of the transition pier of the small side span ratio bridge, and provides a reference for the bridge asymmetrically arranged according to the topography and geology of the mountainous rivers and deep gullies.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of continuous rigid frame bridge construction, in particular to a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method. BACKGROUND

[0002] In the construction of bridges at home and abroad, according to the type of bridge materials, bridges can be divided into masonry arch bridges, concrete bridges, steel bridges and hybrid bridges, etc. The construction technology and advantages of masonry arch bridges cannot meet the needs of current railway and traffic construction. In terms of engineering cost, concrete bridges < steel bridges < hybrid bridges, steel bridges require high-grade highways of grade three and above at the bridge site or river channels with navigation conditions as transportation conditions support, and hybrid bridges are mainly used for cable-stayed bridges with a span of more than 300m. For the conventional case, concrete bridges are used. According to the stress characteristics of the bridge, bridges can be divided into simply supported beam bridges, continuous beam bridges, arch bridges, cable-stayed bridges, suspension bridges, and cable-stayed suspension cooperative system bridges. In terms of engineering cost and construction difficulty, simply supported beam bridges < continuous beam bridges < arch bridges < cable-stayed bridges < suspension bridges < cable-stayed suspension cooperative system bridges. Cable-stayed bridges, suspension bridges and cable-stayed suspension cooperative system bridges are mainly suitable for spans of more than 300m. When the main span is in the range of 50m~300m, continuous beam bridges and arch bridges are the main bridge type scheme. Arch bridges have high requirements for bridge site geology, and the construction risk is also relatively high. Continuous rigid frame bridges have become the first choice for bridges in this span range for crossing waterways and deep gorges due to their crossing ability, superior static and dynamic stress performance, cost advantage and other outstanding advantages. However, engineering practice has shown that in mountainous deep gorges, in high-intensity areas with poor geology, due to factors such as topography, investment scale, flood discharge navigation, scenic areas and existing traffic conditions, the main span of the bridge cannot be adjusted, and the reasonable span arrangement cannot be guaranteed. In order to apply continuous rigid frame bridges to these special conditions, new structural systems and construction methods must be introduced, resulting in small-side-to-middle-span ratio continuous rigid frame bridges. In order to ensure the symmetry of the structure, small-side-to-middle-span ratio continuous rigid frame bridges need to increase the self-weight of the side span to adjust the structural stress, so small-side-to-middle-span ratio special continuous rigid frame bridges are produced.

[0003] The patent application with the application publication number CN112900274 A uses different box girder vertical web (edge span box girder vertical web and midspan box girder vertical web) heights and thicknesses of single-box multi-cell cross-section edge span segments and multi-box multi-cell cross-section midspan segments to solve the imbalance of the self-weight of the bridge edge span and midspan main girder segments with respect to the piers, and maintain the "zero" bending moment state of the piers during construction. The application uses the change in the height and thickness of the edge span box girder and the midspan box girder to achieve construction balance on both sides of the piers. This change in the structure shape of the edge span box girder for balance purposes will result in huge construction waste on one side of the edge span after the construction is completed. Moreover, the application achieves zero bending moment by changing the thickness of the top plate or web, and the use of variable thickness in the structure greatly increases the difficulty of steel bar binding and construction. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art and provide a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method, which solves the limitations of the application of conventional continuous rigid frame bridges in special projects, and the problem of construction waste caused by the need to maintain the "zero" bending moment state of the piers during construction of existing continuous rigid frame bridges.

[0005] The present application is achieved by the following technical solutions:

[0006] A variable-width variable-box asymmetric continuous rigid frame bridge, comprising a foundation, an abutment, a pier, a 0# block box girder, an edge span support cast-in-place beam segment, a main span cantilever cast beam segment, and a midspan closure segment, wherein the foundation is arranged on both sides of the continuous rigid frame bridge, the pier is fixedly arranged on the top of the foundation, and the 0# block box girder is cast on the pier; the main span side of the 0# block box girder is connected with the plurality of main span cantilever cast beam segments, and the main span cantilever cast beam segment is cantilever cast by using a hanging basket; the edge span side of the 0# block box girder is connected with the plurality of edge span support cast-in-place beam segments, and the edge span support cast-in-place beam segment is cast in place by using a support; a counterweight block is arranged on the segment of the edge span support cast-in-place beam segment after the segment of the edge span support cast-in-place beam segment is cast, and the segment of the edge span support cast-in-place beam segment is continuously cast at least two segments of the main span cantilever cast beam segment.

[0007] The 1-2 segments of the edge span support cast-in-place beam segment arranged at the outer end of the edge span side are intersection segments, the intersection segments adopt a "large variable-width horn-shaped" box girder to balance the self-weight of the main span, the top of the abutment arranged at both ends of the continuous rigid frame bridge is connected with the edge span support cast-in-place beam segment by using a support, and the two segments of the main span cantilever cast beam segment are connected by the midspan closure segment to form a bridge deck body.

[0008] The application is a variable-width variable-box asymmetric continuous rigid frame bridge, the side span support cast-in-place beam section adopts a variable-width variable-box "large-width horn-shaped" box girder, the main span cantilever cast beam section is connected through a mid-span closure section, and the construction method is that the side span is cast in place by support and the main span is cantilever cast by a hanging basket, so that the continuous rigid frame bridge can continue to be applied in the case of a small side span ratio and variable-width variable-box, and the economic and durable characteristics of the concrete bridge can continue to be played, and good economic benefits can be achieved. The asymmetric construction method effectively reduces the construction risk caused by the structural asymmetry of the special rigid frame, the side span adopts a variable-width variable-box "large-width horn-shaped" box girder, which provides a solution for balancing the self-weight of the main span and moving the unconditionally arranged flat intersection on the roadbed to the bridge, solves the problem of negative reaction force of the transition pier of the small side span ratio bridge, realizes the economy, environmental coordination and construction convenience of the bridge, and provides a reference for the asymmetrically arranged bridge combined with the terrain and geology of mountain rivers, deep gullies and the like.

[0009] Further, the foundation is selected according to the bearing capacity of the foundation, and a rock-embedded pile foundation, a friction pile foundation or an enlarged foundation is selected, and a bearing platform can be arranged on the foundation.

[0010] Further, the abutment is selected according to the bearing capacity of the foundation and the terrain, and a light abutment, a gravity abutment, a buried abutment or a combined abutment is selected, and the abutment is replaced by a transition pier when the main bridge connects the approach bridge.

[0011] Further, the pier is selected to be a single-limb, double-limb solid, hollow pier or a pile column pier, and the pier section can adopt a circular, rectangular or special shape.

[0012] Further, the 0# block box girder adopts a solid structure, a single-chamber structure or a multi-chamber structure.

[0013] Further, the main span cantilever cast beam section has a constant main span box chamber, and is constructed by a hanging basket cantilever casting method.

[0014] The side span support cast-in-place beam section is increased in box chamber from a standard section to form a "large-width horn-shaped" box girder, a cross partition plate is arranged at the variable-box position, and the section is cast in place by a segmented support or an integral support.

[0015] Further, the side span support cast-in-place beam section and the adjacent joint bridge inter-pier expansion joint adopt a comb-shaped, steel-shaped or polyurethane seamless expansion joint.

[0016] The application can also be realized by another technical scheme as follows:

[0017] A variable-width variable-box asymmetric continuous rigid frame bridge construction method comprises the following steps:

[0018] Step 1, according to the construction conditions, the box girder is divided into multiple segments, the main span side is divided into 2n+1 segments, including 2n main span segments and 1 segment in the middle of the closure, and the side span side is divided into m segments, including m side span segments;

[0019] Step 2, the lower structure foundation, bridge pier and abutment are constructed;

[0020] Step 3, the 0# block box girder is constructed by using a bracket;

[0021] Step 4, a bracket is erected beside the pier and pre-pressed to eliminate non-elastic deformation, and then the 0# block box girder is symmetrically cast in place, after the concrete strength reaches the design requirement, the corresponding prestressed steel beam is tensioned and grouted;

[0022] Step 5, the side span 1' segment cast-in-place support is assembled and pre-pressed, the reinforcement is bound, and then the 1' segment is poured;

[0023] Step 6, after the concrete strength of the 1' segment reaches the design requirement, the counterweight block is arranged on the 1' segment;

[0024] Step 7, the hanging basket on the main span side is assembled and pre-pressed, the reinforcement is bound, and then the 1' segment is poured, after the concrete strength reaches the design requirement, the corresponding prestressed steel beam is tensioned and grouted;

[0025] Step 8, the hanging basket is moved, the reinforcement is bound, the 2' segment is poured, after the concrete strength reaches the design requirement, the corresponding prestressed steel beam is tensioned and grouted;

[0026] Step 9, the side span 2' block cast-in-place support is assembled and pre-pressed, the reinforcement is bound, and then the 2' segment is poured;

[0027] Step 10, after the concrete strength of the 2' segment reaches the design requirement, the counterweight block is moved to the 2' segment;

[0028] Step 11, the hanging basket is moved, the reinforcement is bound, the 3' segment is poured, after the concrete strength reaches the design requirement, the corresponding prestressed steel beam is tensioned and grouted;

[0029] Step 12, the hanging basket is moved, the reinforcement is bound, the 4' segment is poured, after the concrete strength reaches the design requirement, the corresponding prestressed steel beam is tensioned and grouted;

[0030] Step 13, according to the above steps, the side span cast-in-place beam segment is continuously poured, the main span suspension beam segment is continuously poured, the side span m' segment is connected with the abutment, after the side span is poured, the counterweight block is moved to the m' segment, the hanging basket is moved, the reinforcement is bound, the (n-1) # segment is poured, after the concrete strength reaches the design requirement, the corresponding prestressed steel beam is tensioned and grouted;

[0031] Step 14, moving the hanging basket, binding the steel bar, pouring n# segment, after the concrete strength reaches the design requirement, corresponding prestressed steel bundle is tensioned, and grouting is carried out;

[0032] Step 15, the horizontal jacking force is uniformly and synchronously applied at both ends of the cantilever, and the specific jacking force is obtained by combining the closure temperature and the pier stiffness; the mid-span closure section rigid skeleton is installed; the formwork is erected, the steel bar is bound, and the mid-span closure section is poured; after the concrete strength reaches the design requirement, the corresponding prestressed steel bundle is tensioned, and grouting is carried out;

[0033] Step 16, the hanging basket is removed, the side span cast-in-place support is removed, and the counterweight block is removed; the bridge deck concrete pavement is poured; the bridge deck auxiliary facilities are installed, and the bridge operation is carried out.

[0034] Further, the step 13, when n is odd, m'# segment is continuously poured (n-2) # segment, (n-1) # segment and n# segment.

[0035] Further, the m'# segment or m'# segment and (m-1) '# segment are flat intersection sections; the flat intersection section adopts a "large variable-width horn-shaped" box girder to balance the self weight of the main span.

[0036] The application is a variable-width variable-box asymmetric continuous rigid frame bridge construction method, the side span support cast-in-place beam section adopts a variable-width variable-box "large variable-width horn-shaped" box girder; the main span cantilever pouring beam section is connected through the mid-span closure section; the construction method is that the side span is cast-in-place by support, and the main span is cantilever poured by hanging basket. The application makes the continuous rigid frame bridge continue to be applied in the case of small side span ratio and variable-width variable-box, continues to play the economic and durable characteristics of the concrete bridge, and can achieve good economic benefits. The asymmetric construction method effectively reduces the construction risk caused by the asymmetric structure of the special-shaped rigid frame, the side span adopts a variable-width variable-box "large variable-width horn-shaped" box girder, which provides a solution for balancing the self weight of the main span and moving the flat intersection on the roadbed to the bridge, solves the problem of negative reaction force of the transition pier of the small side span ratio bridge, realizes the economy, environmental coordination and construction convenience of the bridge, and provides a reference for the bridge arranged asymmetrically according to the terrain and geology in mountainous rivers and deep gullies.

[0037] Compared with the prior art, the application has the following advantages and beneficial effects:

[0038] 1. The application is a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method, the side span support cast-in-place beam section of the application adopts a variable-width variable-box "large-width horn-shaped" box girder; the main span cantilever cast beam section is connected through the midspan closure section; the construction method is that the side span is cast in place using support, and the main span is cantilever cast using a hanging basket. The application enables the continuous rigid frame bridge to continue to be applied in the case of a small side-to-middle span ratio and variable-width variable-box, and continues to play the economic and durable characteristics of the concrete bridge, so that good economic benefits can be achieved. The asymmetric construction method effectively reduces the construction risk caused by the structural asymmetry of the special rigid frame, the side span adopts a variable-width variable-box "large-width horn-shaped" box girder, which provides a solution for balancing the self-weight of the main span and moving the unconditionally arranged flat intersection on the roadbed to the bridge, and solves the problem of negative reaction force of the transition pier of the small side-to-middle span ratio bridge, realizes the economy, environmental coordination and construction convenience of the bridge, and provides a reference for the asymmetric arrangement of bridges combined with the terrain and geology in mountainous rivers, deep gullies and the like;

[0039] 2. The application is a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method, the small side-to-middle span ratio special continuous rigid frame bridge of the application effectively solves the problems of structural asymmetry in special rigid frame design and high construction risk, and fully considers factors such as limited project construction investment, limited technical ability of construction units, poor transportation conditions and difficulty of large equipment access in economically underdeveloped areas;

[0040] 3. The application is a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method, which specially designs the conventional continuous rigid frame bridge, increases the application range of the continuous rigid frame bridge, solves the problems of structural asymmetry and high construction risk of the small side-to-middle span ratio continuous rigid frame bridge, and can avoid the problems of additional bending moment exceeding the limit of the small side-to-middle span ratio continuous rigid frame pier and overturning of the construction hanging basket;

[0041] 4. The application is a variable-width variable-box asymmetric continuous rigid frame bridge and a construction method, the application adopts counterweight construction to solve the problem of unbalanced bending moment on both sides of the pier, after the closure of the midspan closure section, the two side span support cast-in-place beam sections realize the balance of the bridge structure through mutual interaction force, in addition, the side span support cast-in-place beam section is cast in place using segmented support, so that only the side span support cast-in-place beam section on the side span side and the counterweight gravity slightly greater than the main span cantilever cast beam section on the main span side need to be considered during the continuous rigid frame bridge construction process, without the need for time-consuming and laborious accurate calculation of the construction balance of the side span and the main span, and there is no need to deliberately maintain the "zero" bending moment state of the pier during the construction process, which greatly reduces the construction cost. DETAILED DESCRIPTION

[0042] The drawings described herein are used to provide further understanding of the embodiments of the application, constitute a part of the present application, and do not constitute a limitation to the embodiments of the application. In the drawings:

[0043] Figure 1A structural schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge of the present application;

[0044] Figure 2 A top view structural schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge of the present application;

[0045] Figure 3 A variable-width variable-box asymmetric continuous rigid frame bridge of the present application Figure 1 A cross-sectional structural schematic diagram of the middle 1-1;

[0046] Figure 4 A variable-width variable-box asymmetric continuous rigid frame bridge of the present application Figure 1 A cross-sectional structural schematic diagram of the middle 2-2;

[0047] Figure 5 A steel beam arrangement structural schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge of the present application;

[0048] Figure 6 A construction step schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge method of the present application Figure 1 ;

[0049] Figure 7 A construction step schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge method of the present application Figure 2 ;

[0050] Figure 8 A construction step schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge method of the present application Figure 3 ;

[0051] Figure 9 A construction step schematic diagram of a variable-width variable-box asymmetric continuous rigid frame bridge method of the present application Figure 4 ;

[0052] Markings in the drawings and corresponding part names:

[0053] 1-base, 2-abutment, 3-pier, 4-0# block box girder, 5-edge span support cast-in-place beam section, 6-main span cantilever casting beam section, 7-midspan closure section, 8-steel beam, 9-counterweight. DETAILED DESCRIPTION

[0054] In order to make the person skilled in the art better understand the present application scheme, the technical scheme in the present application embodiment will be described clearly and completely in the following combined with the drawings in the present application embodiment. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0055] It should be noted that the terms "first", "second" and "third" and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a specific sequential or chronological order. It is to be understood that the use of these terms is arbitrary apart from their usage in the specification and the claims to provide clarity and avoid confusion. Furthermore, the terms "comprising", "including", "containing", and "having" and their conjugates, as used herein, are intended to encompass the presence of one or more elements or components without excluding the presence of one or more other elements or components. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application pertains. The materials, methods, and examples provided herein are illustrative only and not intended to be limiting.

[0056] In the present application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate the orientation or positional relationship as shown in the drawings. These terms are mainly used for better description of the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0057] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0058] In addition, the terms "mounting", "setting", "provided with", "connecting", "connecting", "sleeving" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] It should be noted that the embodiments and features in the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0060] Embodiment 1

[0061] As Figures 1-9As shown, the asymmetric continuous rigid frame bridge with variable width and box changes of the present application comprises a foundation 1, an abutment 2, a pier 3, a 0# block box girder 4, a side span support cast-in-place beam section 5, a main span cantilever casting beam section 6, a midspan closure section 7; the top of the abutment 2 is connected with the side span support cast-in-place beam section 5 by a support; a set of foundations 1 is arranged on both sides of a river or a canyon, the bottom of the pier 3 is fixedly connected with the top of the foundation 1, and the top is fixedly connected with the bottom of the 0# box girder 4; the bottom of the 0# block box girder 4 is fixedly connected with the top of the pier 3, the main span side is connected with the main span cantilever casting beam section 6, and the side span side is connected with the side span support cast-in-place beam section 5; the side span support cast-in-place beam section 5 arranged at the outer end of the side span side is a flat intersection section, and the flat intersection section adopts a “large variable width horn-shaped” box girder to balance the self weight of the main span; the box girder balances the self weight of the main span; the “large variable width horn-shaped” is a “large variable width” and a “horn-shaped”. The large variable width is different from the conventional small amplitude variable width, and the large variable width is manifested as a variable box chamber, and the variable width amplitude is large, for example, the box girder is transitioned from a single box single chamber to a single box three chambers, and is transitioned from a standard width of 8 m to 20 m. The “horn-shaped” reflects that the variable width part appears a horn shape in the plan view, and a circular curve is adopted for the variable width transition line. The flat intersection belongs to a component part on a roadbed, the present application considers two cases of no conditionally setting the flat intersection on the roadbed and needing to press the weight on the bridge structure, and creatively sets the flat intersection on the bridge structure. The main span cantilever casting beam section 6 is connected with the midspan closure section 7, the construction method is that the side span support cast-in-place beam section 5 is cast in place by using a segmented support, and the main span cantilever casting beam section 6 is cast in place by using a hanging basket. After pouring a section of the side span support cast-in-place beam section 5, a counterweight block 9 is arranged on the section of the side span support cast-in-place beam section 5, and pouring a section of the side span support cast-in-place beam section 5 corresponds to continuously pouring at least two sections of the main span cantilever casting beam section 6.

[0062] The application discloses a variable-width variable-box asymmetric continuous rigid frame bridge, wherein according to construction conditions, a box girder is divided into multiple sections, the main span side is divided into 2n+1 sections, including 2n main span cantilever casting beam sections 6 and one mid-span closure section 7, and the side span side is divided into m sections, including m side span support cast-in-place beam sections 5; a lower structure foundation 1, a pier 3 and a construction abutment 2 are first constructed; then a support is erected beside the pier 3 and pre-pressed to eliminate non-elastic deformation, and then a 0# block box girder 4 is symmetrically cast in place; after the concrete strength reaches a design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; a side span 1'# section support is assembled and pre-pressed, and then steel bars are bound, and then the 1'# section is poured; after the concrete strength of the 1'# section reaches the design requirement, a counterweight 9 is arranged on the 1'# section; a hanging basket is assembled on the main span side and pre-pressed, steel bars are bound, and then the 1# section is poured; after the concrete strength reaches the design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; the hanging basket is moved, steel bars are bound, and then the 2# section is poured; after the concrete strength reaches the design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; a side span 2' block cast-in-place support is assembled and pre-pressed, steel bars are bound, and then the 2'# section is poured; after the concrete strength of the 2'# section reaches the design requirement, the counterweight 9 is moved to the 2'# section; the hanging basket is moved, steel bars are bound, and then the 3# section is poured; after the concrete strength reaches the design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; the steps are repeated: one side span support cast-in-place beam section 5 is poured, and two main span cantilever casting beam sections 6 are continuously poured; a side span m'# section is connected with the abutment 2, after the side span is poured, the counterweight is moved to the m'# section after the concrete strength of the m'# section reaches the design requirement; the hanging basket is moved, steel bars are bound, and then (n-1)# sections are poured; after the concrete strength reaches the design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; the hanging basket is moved, steel bars are bound, and then n# sections are poured; after the concrete strength reaches the design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; horizontal jacking forces are uniformly and synchronously applied at both ends of the cantilever, and the specific jacking force is calculated according to the closure temperature and the pier body rigidity; a mid-span closure section rigid frame is installed; a form is set, steel bars are bound, and the mid-span closure section is poured; after the concrete strength reaches the design requirement, corresponding prestressed steel strands 8 are tensioned and grouted; the hanging basket is removed, the side span cast-in-place support is removed, and the counterweight 9 is moved out; bridge deck concrete pavement is poured; bridge deck auxiliary facilities are installed, and the bridge is put into operation.

[0063] The asymmetric continuous rigid frame bridge of the application is characterized in that the side span support cast-in-place beam section adopts a variable-width variable-box "large-width horn-shaped" box girder, the main span cantilever cast beam section is connected through a mid-span closure section, and the construction method is that the side span is cast in place by support and the main span is cantilever cast by a hanging basket.

[0064] The asymmetric continuous rigid frame bridge of the application effectively solves the problems of structural asymmetric stress and high construction risk in the design of the asymmetric rigid frame, and fully considers the factors of limited project construction investment, limited technical ability of the construction unit, poor transportation conditions and difficulty of large equipment access in economically underdeveloped areas.

[0065] The asymmetric continuous rigid frame bridge of the application effectively solves the problems of structural asymmetric stress and high construction risk in the design of the asymmetric rigid frame, and fully considers the factors of limited project construction investment, limited technical ability of the construction unit, poor transportation conditions and difficulty of large equipment access in economically underdeveloped areas.

[0066] The asymmetric continuous rigid frame bridge of the application effectively solves the problems of structural asymmetric stress and high construction risk in the design of the asymmetric rigid frame, and fully considers the factors of limited project construction investment, limited technical ability of the construction unit, poor transportation conditions and difficulty of large equipment access in economically underdeveloped areas.

[0067] The foundation 1 is selected according to the bearing capacity of the foundation, and is a rock-embedded pile foundation, a friction pile foundation or an enlarged foundation, and a bearing platform is provided if necessary. The abutment 2 is selected according to the bearing capacity of the foundation and the terrain, and is a light abutment, a gravity abutment, a buried abutment or a combined abutment, and the abutment 2 is replaced by a transition pier when the main bridge connects the approach bridge. The pier 3 can be a single-limb or double-limb solid or hollow pier, or a pile column pier, and the shape can be designed as V-shaped, Y-shaped and X-shaped when landscape is required, and the pier cross section can be circular, rectangular or irregular.

[0068] The 0# block box girder 4 can be selected from solid structure, single chamber structure and multi-chamber structure. The section of the side span support cast-in-place beam section 5 is formed by increasing the box chamber from the standard section to form a "large variable-width horn-shaped" box girder, a transverse partition plate is arranged at the variable box, and the side span box girder is cast in place by using segmented support or integral support. When the side span box girder is cast in place by using integral support, it can be cast in place at one time, or the bottom plate and the web can be cast in place first and then the top plate is cast in place. According to the site topography, geology and flood data, a full-frame support of a disc buckle type or a large steel pipe column type is selected. The main span cantilever casting beam section 6 has a structure similar to that of a conventional continuous rigid frame, the entire main span box chamber is unchanged, and the construction is carried out by using a hanging basket cantilever casting construction. When the main span is less than 100m, a triangular hanging basket is preferably selected.

[0069] The main span cantilever casting beam section 6 has a structure similar to that of a conventional continuous rigid frame, the entire main span box chamber is unchanged, and the construction is carried out by using a hanging basket cantilever casting construction. The main purpose of the present application is to solve the problem of crossing a mountain river or a deep ditch. The topography of this terrain cannot be hoisted and constructed, and the support cannot be erected and constructed. Therefore, the main span cantilever casting beam section 6 is constructed by using a hanging basket cantilever casting construction. During construction, a triangular hanging basket or a rhombic hanging basket is selected according to the size of the main span.

[0070] The main span cantilever casting beam section 6 has a structure similar to that of a conventional continuous rigid frame, the entire main span box chamber is unchanged, and the construction is carried out by using a hanging basket cantilever casting construction. The main purpose of the present application is to solve the problem of crossing a mountain river or a deep ditch. The topography of this terrain cannot be hoisted and constructed, and the support cannot be erected and constructed. Therefore, the main span cantilever casting beam section 6 is constructed by using a hanging basket cantilever casting construction. During construction, a triangular hanging basket or a rhombic hanging basket is selected according to the size of the main span.

[0071] Example 2

[0072] As shown in Figures 6-9 , the construction method of the variable-width variable-box asymmetric continuous rigid frame bridge of the present application is "the side span is cast in place, and the middle span is cast in place by using a hanging basket cantilever casting". The construction steps are as follows:

[0073] Step 1, referring to Figure 2 , according to the construction conditions, the box girder is divided into multiple segments. The main span side is divided into 2n+1 segments, including 2n main span cantilever casting beam sections 6 and 1 middle span closure section 7. The side span side is divided into m segments, including m side span support cast-in-place beam sections (5);

[0074] Step 2, the lower structure foundation 1, the pier 3 and the abutment 2 are constructed;

[0075] Step 3, the 0# block box girder 4 is constructed by using a bracket;

[0076] Step 4, erecting a support beside the pier 3 and pre-pressing to eliminate non-elastic deformation, then symmetrically casting the 0# block box girder (4), after the concrete strength reaches the design requirement, tensioning the corresponding prestressed steel beam 8 and grouting; for the conventional continuous rigid frame bridge, due to the symmetry of the structure, the steel beam arrangement also adopts the symmetric arrangement, and the design is simple. For the scene applied to the continuous rigid frame bridge of the application, the symmetric continuous rigid frame bridge arrangement of the conventional structure cannot be realized, and the asymmetric structure needs to be used, so the steel beam arrangement can only be specially designed. For the small-span continuous rigid frame bridge (span less than 100m), when the calculation meets the requirements, the vertical prestressed steel beam and the transverse prestressed steel beam can not be arranged, and only the longitudinal prestressed steel beam is arranged. For the continuous rigid frame bridge of cantilever pouring construction, each segment has corresponding steel beam, and after the segment is poured, the concrete strength reaches the design requirement, and the corresponding steel beam of the segment needs to be tensioned.

[0077] Step 5, assembling the side span 1' # segment cast-in-place support and pre-pressing, binding the steel bars, and then pouring the 1' # segment;

[0078] Step 6, setting the counterweight block 9 on the 1' # segment after the concrete strength of the 1' # segment reaches the design requirement;

[0079] Step 7, assembling the hanging basket on the main span side and pre-pressing, binding the steel bars, and then pouring the 1' # segment, after the concrete strength reaches the design requirement, tensioning the corresponding prestressed steel beam 8 and grouting;

[0080] Step 8, moving the hanging basket, binding the steel bars, pouring the 2' # segment, after the concrete strength reaches the design requirement, tensioning the corresponding prestressed steel beam 8 and grouting;

[0081] Step 9, assembling the side span 2' block cast-in-place support and pre-pressing, binding the steel bars, and then pouring the 2' # segment;

[0082] Step 10, moving the counterweight block 9 to the 2' # segment after the concrete strength of the 2' # segment reaches the design requirement;

[0083] Step 11, moving the hanging basket, binding the steel bars, pouring the 3' # segment, after the concrete strength reaches the design requirement, tensioning the corresponding prestressed steel beam 8 and grouting; Step 12, moving the hanging basket, binding the steel bars, pouring the 4' # segment, after the concrete strength reaches the design requirement, tensioning the corresponding prestressed steel beam 8 and grouting;

[0084] Step 13, according to the above steps: pouring a segment of the side span support cast-in-place beam section 5 corresponds to continuously pouring two segments of the main span cantilever beam section 6; the construction side span m' # section is connected with the abutment 2, and after the side span pouring is completed, the counterweight block is moved to the m' # section after the concrete strength of the m' # section reaches the design requirement; the hanging basket is moved, the reinforcement is bound, the (n-1) # section is poured, the corresponding prestressed steel strand 8 is tensioned after the concrete strength reaches the design requirement, and the grouting is pressed; the present application adopts the counterweight construction, solves the problem of unbalanced bending moment of the bridge pier on both sides, and after the closure section in the midspan is closed, the side span support cast-in-place beam section on both sides realizes the balance of the bridge structure through the interaction force, in addition, the side span support cast-in-place beam section adopts the segmented support cast-in-place, so that in the continuous rigid frame bridge construction process, only the side span support cast-in-place beam section on the side span side and the gravity of the counterweight block slightly greater than the main span side main span cantilever beam section need to be considered, without the need for time-consuming and laborious accurate calculation of the construction balance of the side span and the main span, there is no need to deliberately maintain the "zero" bending moment state of the bridge pier in the construction process;

[0085] Step 14, moving the hanging basket, binding the reinforcement, pouring the n# section, tensioning the corresponding prestressed steel strand 8 after the concrete strength reaches the design requirement, and pressing the grouting;

[0086] Step 15, uniformly and synchronously applying horizontal jacking force at both ends of the cantilever, the specific jacking force should be calculated according to the closure temperature and the pier stiffness; installing the midspan closure section rigid framework; erecting the formwork, binding the reinforcement, and pouring the midspan closure section; tensioning the corresponding prestressed steel strand 8 after the concrete strength reaches the design requirement, and pressing the grouting;

[0087] Step 16, removing the hanging basket, removing the side span cast-in-place support, and moving out the counterweight block 9; pouring the bridge deck concrete pavement; installing the bridge deck auxiliary facilities, and operating the completed bridge.

[0088] The step 13, when n is even, a segment of the side span support cast-in-place beam section 5 corresponds to continuously pouring two segments of the main span cantilever beam section 6; when n is odd, the m' # section corresponds to continuously pouring (n-2) # section, (n-1) # section and n # section. This construction scheme can greatly improve the construction efficiency of the continuous rigid frame bridge. The m' # section or the m' # section and the (m-1)'# section are intersection sections; according to the continuous rigid frame bridge construction conditions, when the side span is relatively short, only the side span support cast-in-place beam section 5 at the end of the side span is arranged as the intersection section, and when the side span is relatively long, two sections can be arranged as the intersection section, and the intersection section adopts a "large variable-width horn-shaped" box girder to balance the self-weight of the main span. The setting of the intersection section is one of the invention points of the present application, and the intersection belongs to the component part on the roadbed. The present application considers the two conditions of the roadbed without the condition to set the intersection and the bridge structure needing to be weighted, and creatively sets the intersection on the bridge structure.

[0089] The application is a variable-width variable-box asymmetric continuous rigid frame bridge construction method, the side span support cast-in-place beam section adopts a variable-width variable-box "large-width horn-shaped" box girder, the main span cantilever cast beam section is connected through a mid-span closure section, and the construction method is that the side span is cast in place by using a support, and the main span is cantilever cast by using a hanging basket. The application makes the continuous rigid frame bridge continue to be applied in the case of a small side-to-middle span ratio and variable-width variable-box, and continues to play the economic and durable characteristics of the concrete bridge, so that good economic benefits can be achieved. The asymmetric construction method effectively reduces the construction risk caused by the structural asymmetry of the special rigid frame, the side span adopts a variable-width variable-box "large-width horn-shaped" box girder, which provides a solution for balancing the self-weight of the main span and moving the unconditionally arranged flat intersection on the roadbed to the bridge, and solves the problem of negative reaction force of the transition pier of the small side-to-middle span ratio bridge, realizes the economy, environmental coordination and construction convenience of the bridge, and provides a reference for the bridge arranged asymmetrically according to the terrain and geology in mountainous rivers and deep gullies.

[0090] The small side-to-middle span ratio special continuous rigid frame bridge effectively solves the problems of structural asymmetry and high construction risk in the design of the special rigid frame, and fully considers the factors of limited project construction investment, limited technical ability of the construction unit, poor transportation conditions and difficulty of large equipment access in economically underdeveloped areas.

[0091] The special design of the conventional continuous rigid frame bridge increases the application range of the continuous rigid frame bridge, solves the problems of force asymmetry and high construction risk of the small side-to-middle span ratio continuous rigid frame bridge, and can avoid the problems of over-limit additional bending moment of the small side-to-middle span ratio continuous rigid frame pier and overturning of the construction hanging basket.

[0092] The application adopts counterweight construction to solve the problem of unbalanced bending moment on both sides of the pier, after the closure of the mid-span closure section, the side span support cast-in-place beam section realizes the balance of the bridge structure through the interaction force, in addition, the side span support cast-in-place beam section is cast in place by using segmented support, so that only the side span support cast-in-place beam section on the side span side and the counterweight gravity slightly larger than the main span cantilever cast beam section on the main span side need to be considered in the continuous rigid frame bridge construction process, without the need for time-consuming and laborious accurate calculation of the construction balance of the side span and the main span, and there is no need to deliberately maintain the "zero" bending moment state of the pier in the construction process, which greatly reduces the construction cost.

[0093] For example, a 180m cantilever cast arch bridge crossing a deep valley, the excavation strength of the arch seat foundation reaches 100MPa of 120,000m of limestone, and if the bridge type scheme of the application is adopted, the engineering cost can be saved by about 40 million yuan.

[0094] The above detailed description of the specific embodiments of the present application has been given to understand the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A variable-width, variable-box asymmetric continuous rigid frame bridge, comprising a foundation (1), abutments (2), piers (3), a No. 0 block box girder (4), cast-in-place beam segments for side span supports (5), cantilever beam segments for the main span (6), and a mid-span closure segment (7), characterized in that: Foundations (1) are set on both sides of the continuous rigid frame bridge. Piers (3) are fixed on the top of the foundations (1). Box girder (4) of block 0 is cast on the pier (3). The main span side of the box girder (4) of block 0 is connected to multiple main span cantilever beam segments (6). The main span cantilever beam segments (6) are cast using hanging baskets. The side span side of the box girder (4) of block 0 is connected to multiple side span support cast-in-place beam segments (5). The side span support cast-in-place beam segments (5) are cast using supports. After casting a side span support cast-in-place beam segment (5), counterweights (9) are set on the side span support cast-in-place beam segment (5). Casting a side span support cast-in-place beam segment (5) corresponds to continuously casting at least two main span cantilever beam segments (6). The 1-2 sections of cast-in-place beams (5) on the outer side of the side span are level crossing sections. The level crossing sections adopt "large-width trumpet-shaped" box girders to balance the self-weight of the main span. The top of the abutments (2) set at both ends of the continuous rigid frame bridge is connected to the cast-in-place beams (5) on the side span by bearings. The cantilever beams (6) on both sides of the main span are connected by the mid-span closure section (7) to form the bridge deck.

2. The variable-width, variable-box asymmetric continuous rigid frame bridge according to claim 1, characterized in that: The foundation (1) is selected from rock-socketed pile foundation, friction pile foundation or enlarged foundation according to the bearing capacity of the foundation, and a pile cap is set on the foundation (1).

3. The variable-width, variable-box asymmetric continuous rigid frame bridge according to claim 1, characterized in that: The bridge abutment (2) is selected from lightweight bridge abutments, gravity bridge abutments, buried bridge abutments or combined bridge abutments according to the bearing capacity of the foundation and the terrain. When the main bridge connects to the approach bridge, the bridge abutment (2) is replaced by a junction pier.

4. The variable-width, variable-box, asymmetric continuous rigid frame bridge according to claim 1, characterized in that: The cross-section of the bridge piers can be circular, rectangular, or irregular.

5. The variable-width, variable-box asymmetric continuous rigid frame bridge according to claim 1, characterized in that: The 0# block box girder (4) is selected from solid structure, single-cell structure or multi-cell structure.

6. The variable-width, variable-box, asymmetric continuous rigid frame bridge according to claim 1, characterized in that: The main span cantilever beam segment (6) remains unchanged throughout the main span box girder and is constructed using hanging basket cantilever construction. The cross section of the side span support cast-in-place beam segment (5) is formed by adding a box chamber to the standard cross section to form a "large wide trumpet-shaped" box beam. A transverse diaphragm is set at the box chamber, and the segmented support cast-in-place or the whole support cast-in-place is adopted.

7. The variable-width, variable-box asymmetric continuous rigid frame bridge according to claim 1, characterized in that: The expansion joint between the cast-in-place beam segment (5) of the side span support and the adjacent connecting bridge adopts a comb-tooth type, steel type or polyurethane seamless expansion joint.

8. A construction method for a variable-width, variable-box asymmetric continuous rigid frame bridge, characterized in that, Including the following steps: Step 1: According to the construction conditions, the box girder is divided into multiple segments. The main span side is divided into 2n+1 segments, including 2n main span cantilever beam segments (6) and 1 mid-span closure segment (7). The side span side is divided into m segments, including m side span support cast-in-place beam segments (5). Step 2: Construct the substructure foundation (1), piers (3), and abutments (2); Step 3: Construct the No. 0 block box girder (4) using a bracket. Step 4: Erect a support frame next to the pier (3) and pre-stress it to eliminate inelastic deformation. Then cast the 0# block box girder (4) symmetrically. After the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout them. Step 5: Assemble the cast-in-place support for the 1'# segment of the side span and pre-stress it, tie the reinforcing bars, and then pour the 1'# segment; Step 6: After the concrete strength of segment 1'# reaches the design requirements, set counterweights (9) on segment 1'#. Step 7: Assemble the hanging basket on the side of the main span and pre-stress it, tie the steel bars, and then pour segment 1. After the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout them. Step 8: Move the hanging basket, tie the reinforcing bars, pour the No. 2 segment, and after the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout them; Step 9: Assemble the cast-in-place support for the 2'# segment of the side span and pre-stress it, tie the reinforcing bars, and then pour the 2'# segment; Step 10: After the concrete strength of segment 2'# reaches the design requirements, move the counterweight (9) onto segment 2'#. Step 11: Move the hanging basket, tie the reinforcing bars, pour the No. 3 segment, and after the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout them; Step 12: Move the hanging basket, tie the reinforcing bars, pour the No. 4 segment, and after the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout. Step 13: Repeat the above steps: pour a section of cast-in-place beam segment (5) on the side span support and continuously pour two sections of cantilever beam segment (6) on the main span; connect the construction side span m'# segment to the abutment (2); after the side span is poured, after the concrete strength of m'# segment reaches the design requirements, move the counterweight block to m'# segment; move the hanging basket, tie the reinforcing bars, pour (n-1)# segment, and after the concrete strength reaches the design requirements, tension the corresponding prestressed steel strand (8) and grout; Step 14: Move the hanging basket, tie the reinforcing bars, pour the n# segment, and after the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout. Step 15: Apply horizontal jacking force at both ends of the cantilever at a uniform speed and synchronously. The specific jacking force should be calculated in combination with the closure temperature and the stiffness of the pier body; install the stiffening frame of the mid-span closure section; erect the formwork, tie the reinforcing bars, and pour the mid-span closure section; after the concrete strength reaches the design requirements, tension the corresponding prestressed steel strands (8) and grout. Step 16: Remove the hanging basket, remove the side span cast-in-place support, and remove the counterweight block (9); pour the bridge deck concrete pavement; install the bridge deck ancillary facilities, and put the bridge into operation.

9. The construction method for a variable-width, variable-box asymmetric continuous rigid frame bridge according to claim 8, characterized in that: In step 13, when n is an odd number, the pouring of segment m'# corresponds to the continuous pouring of segments (n-2)#, (n-1)#, and n#.

10. A construction method for a variable-width, variable-box asymmetric continuous rigid frame bridge according to claim 8 or 9, characterized in that: The m'# segment or the m'# segment and (m-1)'# segment are at-grade intersections; the at-grade intersections adopt "large-width trumpet-shaped" box girders to balance the self-weight of the main span.

Images