Single-tower self-anchored suspension bridge with bridge deck width greater than 40 m and construction method

Abstract

The application discloses a single-tower self-anchored suspension bridge with a bridge width greater than 40m and a construction method, which comprises a bridge main body, a cable tower and a cable saddle; the cable tower adopts a single-column cantilever structure, the bottom of the cable tower is fixed with the ground, and the top of the cable tower is used for bearing main cables; the main cables form a spatial multi-cable plane system; the cable saddle comprises side cable saddles and a middle cable saddle, the two side cable saddles are distributed on the outer side, the middle cable saddle is arranged between the two side cable saddles, and the saddle base plate is connected with the cable tower. The structural system greatly improves the width application range of the single-tower self-anchored suspension bridge; effectively reduces the beam height of the large-width single-tower self-anchored suspension bridge, improves the bridge deck stiffness, reduces the material index of each square meter of the bridge deck, improves the structural span capacity and economy; effectively reduces the beam height of the large-width single-tower self-anchored suspension bridge, greatly reduces the approach length, reduces the engineering construction scale, and simultaneously makes the structure more light and beautiful and has a better landscape effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of bridge construction, and particularly relates to a single-tower self-anchored suspension bridge with a bridge deck width greater than 40 m and a construction method. BACKGROUND

[0002] With the rapid development of social economy and traffic volume, the combination of super multi-lane and multi-functional channel has become a new trend in bridge construction, leading to an increasing demand for bridge deck width, and more and more bridges with a deck width greater than 40 m, thus giving rise to super-wide bridges, some of which have a deck width of 70 m, and the typical Xihoumen Bridge has a main deck width of 68 m.

[0003] The structural stress of a super-wide bridge is mainly controlled by the bridge deck width. For a large-span super-wide suspension bridge, a single-tower self-anchored suspension bridge with a spatial cable plane is a commonly used structural type. The single-tower self-anchored suspension bridge has the main aesthetic features of a traditional suspension bridge, is unique and spectacular in bridge type, and has lively and lively spatial main cables, which can often become a landscape highlight of a city bridge, such as the new San Francisco Bay Bridge in Oakland, USA. The single-tower self-anchored suspension bridge significantly improves the torsional stiffness of the bridge and enhances the wind stability through the arrangement of the spatial cable plane. However, for a super-wide bridge, due to the wide bridge deck and large lateral span of the bridge structure, the bridge deck system has the characteristics of high height and large cross-sectional size, resulting in a sharp increase in the amount of steel used for the bridge deck system, greatly increasing the construction cost. Moreover, due to the large lateral span of the bridge structure, the vertical stiffness of the bridge deck is difficult to guarantee, and the vertical deflection is large, reducing the driving comfort of the bridge. On the other hand, due to the large height of the main body of the bridge deck, the length of the approach is greatly increased, increasing the scale of the bridge construction, and affecting the landscape effect of the bridge.

[0004] The single-tower self-anchored suspension bridge with a spatial cable plane generally uses a three-dimensional spatial line shape, and the structural stress has complexity. In the traditional design of this type of bridge, a double-main-cable structural type is generally used, and the stress of the main cable is symmetrical, greatly reducing the design difficulty. However, for a super-wide bridge, the applicability of the double-main-cable is restricted.

[0005] In some related technologies, the height and cross-sectional size of the bridge deck system beam are generally increased, which further leads to an increase in the weight of the bridge deck system, causing a vicious cycle of an increase in the constant bending moment of the beam, leading to difficulties in beam design, and the stiffness of the bridge deck system is improved to a limited extent, greatly increasing the engineering cost of the bridge. On the other hand, increasing the number of transverse tower columns and using a double-deck arrangement will increase the amount of foundation engineering and greatly increase the engineering cost of the bridge, and it is often difficult to obtain a good landscape effect.

[0006] Increasing the main cable of the suspension bridge can well avoid increasing the height and cross-sectional size of the bridge deck system beam, improving the bridge deck stiffness, and realizing good economy, but for the spatial cable plane self-anchored suspension bridge, the side main cable presents a spatial cable plane, and the middle main cable is a plane cable plane, the main cable length, stress and linear have significant differences, the design and construction are difficult, which may lead to difficulties in main beam closure, large fatigue stress amplitude and the like. SUMMARY

[0007] In view of the problems in the prior art, the present application provides a single-tower self-anchored suspension bridge with a bridge deck width greater than 40m and a construction method.

[0008] The present application is implemented in the following way: a single-tower self-anchored suspension bridge with a bridge deck width greater than 40m, comprising a bridge deck main body, a cable tower, and a lock saddle installed at the top of the cable tower for connecting the main cable, characterized in that: the bridge deck main body adopts a split structure, comprising a stiffening beam and a beam, and the beam and the stiffening beam are fixedly connected to form the bridge deck main body together;

[0009] The cable tower adopts a single-column cantilever structure, the bottom of the cable tower is fixedly connected to the ground, and the top of the cable tower is used for bearing the main cable;

[0010] The main cable forms a spatial multi-cable plane system, and the main cable includes two side main cables and one middle main cable, the two side main cables are symmetrically installed on both sides of the top of the cable tower through the saddle and connected to both ends of the beam in the bridge deck main body through the side hanger rods, and the middle main cable is installed in the middle of the top of the cable tower through the saddle and connected to the middle of the beam in the bridge deck main body through the middle hanger rod; both ends of the main cable are anchored to the bridge deck main body or the ground;

[0011] The saddle includes two side saddles and a middle saddle, the two side saddles are distributed on the outside, and the middle saddle is arranged between the two side saddles, and the saddle base plate is connected to the cable tower.

[0012] Preferably, the bridge deck main body adopts a split steel box beam or a split steel truss beam.

[0013] Preferably, the planar projection of the side main cable is a symmetric curve, and the curve opening faces the outside, and the planar projection of the middle main cable is a straight line.

[0014] Preferably, the two side main cables and the middle main cable constituting the main cable are arranged asymmetrically, and the side main cable and the middle main cable are anchored on the bridge deck main body at the middle span end and fixed to the ground at the side span.

[0015] Preferably, the two side saddles adopt an integral structure, and the side saddle and the middle saddle are adjustably fixed to the saddle base plate.

[0016] Preferably, the two edge main cables and the middle main cable constituting the main cable are symmetrically arranged, the edge main cable and the middle main cable are anchored at the bridge deck body, the edge cable saddle and the middle cable saddle constituting the cable saddle adopt an integral structure, and the top of the pylon is fixedly connected.

[0017] Preferably, the distance from the center of the middle cable saddle to the center of the two side cable saddles is equal, so as to ensure the balance of stress.

[0018] The maximum stress of the cross beam is adjustable, and the specific design formula is:

[0019]

[0020] Wherein, W is the bending modulus of the cross beam, Q(x) is the transverse load of the cross beam, M Δ1 and M Δ2 are the bending moments of the top surface and the bottom surface of the cross beam respectively due to the vertical deformation of the middle suspender, and L is the transverse distance between the left and right edge main cable suspenders.

[0021] The application further discloses a construction method of the single-pylon self-anchored suspension bridge, and has the characteristics that the method comprises the following steps.

[0022] Step 1, constructing the pylon;

[0023] Step 2, erecting a support and arranging a temporary support at the bottom of the bridge deck body;

[0024] Step 3, erecting the main cable;

[0025] Step 31, installing the edge cable saddle and the middle cable saddle at the top of the pylon, determining the initial offset of the edge cable saddle, determining the unstressed length of the edge main cable, and erecting the edge main cable so that the edge main cable is in an empty cable state;

[0026] Step 32, determining the initial offset of the middle cable saddle, determining the unstressed length of the middle main cable, and erecting the middle main cable so that the middle main cable is in an empty cable state;

[0027] Step 4, installing the temporary suspender of the edge main cable;

[0028] Step 41, edge main cable shape conversion: at the two sides of the bridge deck body, a temporary suspender is installed at a certain distance, the temporary suspender is used to connect the cross beam and the edge main cable, the edge main cable is temporarily diverted, the edge main cable is preliminarily changed from the empty cable state to the bridge state, the cable shape is checked, and the transverse offset and the transverse angle of the main cable are checked;

[0029] Step 42, synchronous jacking and resetting of the edge cable saddle: for the asymmetric main cable arrangement, the edge cable saddle is synchronously jacked and reset according to the design requirements;

[0030] Step 5, installing the permanent suspender of the main cable and the shape conversion;

[0031] Step 51, middle main cable suspender installation and preliminary tensioning: install the middle main cable suspender, realize the connection between the main cable and the bridge deck main body, and preliminarily tension the main cable suspender;

[0032] Step 52, synchronous pushing and resetting of the middle cable saddle: for the asymmetric main cable arrangement, according to the design requirements, the middle cable saddle synchronously pushes and resets the middle main cable suspender installation;

[0033] Step 53, installation of the side main cable permanent suspender and removal of the side main cable temporary suspender: after the preliminary tensioning of the middle main cable suspender and the pushing and resetting of the cable saddle, the side main cable temporary suspender is gradually removed, the side main cable permanent suspender is installed, and the main cable line shape is further adjusted so that the main cable realizes the target line shape;

[0034] Step 6, removal of the support, secondary tensioning of the main cable suspender, optimization of the internal force of the bridge deck main body, and completion of the main structure construction of the super-wide single-tower self-anchored suspension bridge.

[0035] Preferably, in steps 31 and 32, the balance equation of the main cable is:

[0036]

[0037] ω(x)=w

[0038] where H is the horizontal internal force of the main cable, z represents the vertical coordinate of the main cable, x represents the coordinate in the bridge axis direction, and w represents the unit length mass of the main cable.

[0039] Preferably, in steps 31 and 32, the vertical coordinate of the main cable is determined by the parabolic method:

[0040]

[0041] where f is the sag of the main cable, and l is the calculation span.

[0042] Preferably, in step 41, the balance equation of the main cable is:

[0043]

[0044]

[0045] where T i is the horizontal internal force of the main cable, y represents the transverse coordinate of the main cable, x represents the coordinate in the bridge axis direction, and ω i represents the unit length mass of the main cable, and l i represents the length of the calculation section of the main cable along the bridge axis.

[0046] Preferably, step 42, first, according to the principle of no stress length change, the offset amount Δ1 of the side cable saddle is calculated, so that the side main cable on both sides of the side cable saddle meets the balance condition of the unbalanced force of the balance tower, and the influence of the central cable saddle is considered, and the side cable saddle is continuously reset during the temporary suspender installation process.

[0047] Preferably, step 52, first, according to the principle of no stress length change, the offset amount Δ2 of the central cable saddle is calculated, considering that the offset amount Δ3 of the central cable saddle changes during the side cable saddle jacking reset process, and the side cable saddle is continuously reset during the central suspender installation process, and the reset offset amount is Δ2+Δ3.

[0048] The application has the advantages and technical effects:

[0049] (1) The structural system provided by the application greatly improves the width application range of the single-tower self-anchored suspension bridge.

[0050] (2) The structural system provided by the application effectively reduces the beam height of the large-width single-tower self-anchored suspension bridge, reduces the material index per square meter of the bridge deck, improves the structural spanning capacity and economy.

[0051] (3) The structural system provided by the application effectively reduces the beam height of the large-width single-tower self-anchored suspension bridge, greatly reduces the approach length, reduces the engineering construction scale, and at the same time, makes the structure more lightweight and beautiful, and has better landscape effect.

[0052] (4) The application increases the main cable, which is equivalent to increasing the elastic support in the transverse direction, effectively improves the stiffness of the bridge deck main body, and improves the driving comfort.

[0053] (5) The application adopts the single-tower self-anchored spatial multi-cable plane system, which improves the torsional stiffness of the whole bridge.

[0054] (6) The application uses a reasonable construction method to ensure the line shape of the side and central main cables after the bridge is completed, reasonably distributes the load of the side and central main cables, and increases the harmony and unity of the bridge force and beauty. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 is a three-dimensional structural schematic diagram of an asymmetric super-wide single-tower self-anchored suspension bridge;

[0056] Figure 2 is an elevation view of an asymmetric super-wide single-tower self-anchored suspension bridge;

[0057] Figure 3 is a schematic diagram of a split-type saddle;

[0058] Figure 4 is a three-dimensional structural schematic diagram of a symmetric super-wide single-tower self-anchored suspension bridge;

[0059] Figure 5 is a vertical view of a symmetrical super-wide single-tower self-anchored suspension bridge.

[0060] In the figure, 1, edge main cable; 2, middle main cable; 3, cable saddle; 3-1, edge cable saddle; 3-2, middle cable saddle; 4, suspender; 5, second anchoring end; 6, cable tower; 7, stiffening girder; 8, cross beam; 9, first anchoring end; 10, contact surface; 11, cable saddle base plate. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0062] Please refer to Figures 1 to 5 , based on the prior art, the present application provides a single-tower self-anchored suspension bridge with a bridge deck width greater than 40m, comprising a bridge deck main body, a cable tower 6, and a saddle 3 installed at the top of the cable tower for connecting the main cable. The bridge deck main body adopts a split structure, comprising a stiffening girder 7 and a cross beam 8, and the cross beam and the stiffening girder are fixedly connected to form the bridge deck main body.

[0063] The cable tower adopts a single-column cantilever structure, the bottom of the cable tower is fixedly connected to the ground, and the top of the cable tower is used for bearing the main cable;

[0064] The main cable forms a spatial multi-cable surface system, and the main cable comprises three main cables, two edge main cables 1 and one middle main cable 2. The two edge main cables are symmetrically installed on both sides of the top of the cable tower through the cable saddle and are connected to the two ends of the cross beam in the bridge deck main body through the edge suspender. The middle main cable is installed in the middle of the top of the cable tower through the cable saddle and is connected to the middle of the cross beam in the bridge deck main body through the middle suspender. The two ends of the main cable are anchored to the bridge deck main body or the ground.

[0065] The cable saddle comprises two edge cable saddles 3-1 and one middle cable saddle 3-2, the two edge cable saddles are distributed on the outside, and the middle cable saddle is arranged between the two edge cable saddles. The cable saddle base plate is connected to the cable tower.

[0066] Preferably, the bridge deck main body adopts a split steel box girder or a split steel truss girder.

[0067] Preferably, the planar projection of the edge main cable is a symmetrical curve, the curve opening is outward, and the planar projection of the middle main cable is a straight line. The main cable forms a spatial multi-cable surface system, which improves the torsional stiffness of the bridge and improves the wind stability.

[0068] Preferably, the two edge main cables and the middle main cable constituting the main cable are arranged asymmetrically, the edge main cable and the middle main cable are anchored to the bridge deck main body at the middle span end, and the edge main cable and the middle main cable are fixedly connected to the ground at the side span.

[0069] Preferably, the two side cable saddles adopt an integral structure, and the side cable saddles and the middle cable saddle are respectively fixedly and adjustablely connected to the cable saddle seat plate, which improves construction efficiency and facilitates on-site adjustment.

[0070] Preferably, the two side main cables and the middle main cable that make up the main cable are arranged symmetrically, and the two ends of the side main cables and the middle main cables are anchored to the main body of the bridge deck. The side cable saddles and the middle cable saddles that make up the cable saddles adopt an integral structure and are fixed at the top of the tower, which improves construction efficiency and the overall strength of the cable saddles.

[0071] Preferably, the distance from the center of the middle saddle to the centers of the two side saddles is equal to ensure the balance of force.

[0072] Application Example 1:

[0073] Please see Figure 1 , Figure 2 A single-tower self-anchored suspension bridge with a deck width greater than 40m includes a bridge deck body, a tower 6, main cables, cable saddles 3, and suspenders 4. The bridge deck body adopts a split structure, including stiffening beams 7 and crossbeams 8, which are fixed together to form the bridge deck body, serving as the working surface for bridge traffic, etc. The tower 6 adopts a single-column cantilever structure, with the bottom of the tower 6 fixed to the ground and the top of the tower 6 used to support the main cables. The main cables include three cables: side main cables 1 and middle main cables 2. There are two side main cables, which are symmetrically installed on both sides of the top of the tower 6 via cable saddles 3 and connected to both ends of the crossbeam 8 in the bridge deck body via side suspenders 4-1. There is one middle main cable 2, which is installed in the middle of the top of the tower 6 via cable saddles 3 and connected to the middle of the crossbeam 8 in the bridge deck body via middle suspenders 4-2. The main cables are connected to the bridge deck body at the first anchorage end 9 and anchored to the ground through the bridge deck body at the second anchorage end 5, adopting an asymmetrical arrangement. At the main span of the bridge ( Figure 1 (Tower 6, right side), the planar projection of the side main cable 1 is a symmetrical curve with the curve opening outwards, and the planar projection of the middle main cable 2 is a straight line; at the bridge side span location ( Figure 1 On the left side of tower 6, the side main cable 1 and the middle main cable 2 are arranged parallel to each other, with their planar projections being straight lines. The main cables form a spatial multi-cable surface system, improving the bridge's torsional stiffness and wind resistance. The cable saddle 3 includes two side saddles 3-1 and one middle saddle 3-2, for a total of three. The two side saddles 3-1 are distributed on the outer sides, forming a whole connected to the saddle base plate 11; the middle saddle 3-2 is located in the middle, and can slide relative to the side saddles 3-1 and the saddle base plate 11 along the contact surface 10 to allow for different adjustment of the side saddles 3-1 and the middle saddle 3-2. The saddle base plate 11 is connected to tower 6, and its top is connected to both the side main cable 1 and the middle main cable 2, serving as a load-bearing transfer component between the main cable 1 and tower 6. The suspender 4 connects the main cable to the bridge deck and is an important load-bearing force-transfer component of the suspension bridge.

[0074] For the traditional double main cable, considering the uniform distribution of the load in the transverse direction of the beam, the maximum stress of the beam is:

[0075]

[0076] wherein Q(x) is the load in the transverse direction of the beam. The force requirement cannot be met, and therefore the main cable adopted in the present application comprises three main cables, i.e., the side main cable 1 and the middle main cable 2

[0077] When three main cables are adopted, the maximum stress of the beam is:

[0078]

[0079] wherein W is the bending modulus of the beam, Q(x) is the load in the transverse direction of the beam, M Δ1 and M Δ2 are the bending moments on the top surface and the bottom surface of the beam respectively, which are caused by the vertical deformation of the middle suspender, and L is the transverse distance between the suspenders of the left and right side main cables.

[0080] The vertical deformation of the suspender can be reasonably designed to effectively adjust the bending moment of the beam. Specifically, the adjustment of the middle suspender can adjust the sizes of M Δ1 and M Δ2 to change the stress distribution of the beam, so as to realize the stress adjustability and design flexibility. For the purpose of comparison, under the condition that the vertical deformation of the middle suspender is not considered, the bending modulus of the beam of the present application is 0.56 times that of the traditional design method under the condition that the maximum stress of the beam is the same, and obviously the height of the beam can be significantly reduced. Preferably, the force of the beam can be optimized by adjusting the cable saddle and the suspender.

[0081] The present application also discloses a construction method of the above-mentioned single-tower self-anchored suspension bridge, which comprises the following steps:

[0082] Step 1: constructing the cable tower; the tower is constructed by using the climbing formwork or the turnover formwork for segmental cast-in-situ construction;

[0083] Step 2: erecting the support and setting the temporary support at the bottom of the main body of the bridge deck; the segmental construction of the main body of the bridge deck is completed in the factory, the segments are spliced into a whole at the construction site, the main body of the bridge deck is jacked into position, the temporary support is set at the bottom of the main body of the bridge deck, and the construction of the main body of the bridge deck is completed;

[0084] Step 3: erecting the main cable;

[0085] Step 31: installing the side cable saddle 3-1 and the middle cable saddle 3-2 on the top of the cable tower 6 respectively, determining the initial offset of the side cable saddle, determining the unstressed length of the side main cable, and erecting the side main cable so that the side main cable is in the empty cable state;

[0086] Step 32: determine the initial offset of the middle saddle, determine the unstressed length of the middle main cable, and erect the middle main cable so that the middle main cable is in the empty cable state;

[0087] In the above steps 31 and 32, the balance equation of the main cable is:

[0088]

[0089] ω(x)=w

[0090] Where H is the horizontal internal force of the main cable, z represents the vertical coordinate of the main cable, x represents the coordinate in the bridge axis direction, and w represents the unit length mass of the main cable;

[0091] In the above steps 31 and 32, the vertical coordinate of the main cable is determined by the parabolic method:

[0092]

[0093] Where f is the sag of the main cable, and l is the calculation span;

[0094] Step 4, temporary hoist installation of the side main cable 1;

[0095] Step 41, side main cable shape conversion: temporary hoists are installed every certain distance on both sides of the main body of the bridge deck, the temporary hoists are used to connect the cross beam 8 and the side main cable 1, the side main cable is temporarily diverted, the side main cable is preliminarily changed from the empty cable state to the bridge state, the cable shape is checked, and the transverse offset and transverse angle of the main cable are checked. In the above step 41, the balance equation of the main cable is:

[0096]

[0097]

[0098] Where T i is the horizontal internal force of the main cable, y represents the transverse coordinate of the main cable, x represents the coordinate in the bridge axis direction, and ω i represents the unit length mass of the main cable, and l i represents the length of the calculation section of the main cable along the bridge axis;

[0099] Step 42, synchronous jacking and resetting of the side saddle: for the asymmetric main cable arrangement, the side saddle 3-1 is synchronously jacked and reset according to the design requirements. First, the offset Δ1 of the side saddle is calculated according to the principle that the unstressed length is unchanged, so that the balance conditions of the side main cables on both sides of the side saddle satisfy the unbalanced force of the balance saddle, and the influence of the middle saddle is considered. The side saddle is continuously reset during the temporary hoist installation process.

[0100] Step 5, installation of the permanent hoist of the main cable and shape conversion;

[0101] Step 51, installation and preliminary tensioning of the middle main cable suspender 4-1: the middle main cable suspender is installed, the connection between the main cable and the bridge deck main body is realized, and the main cable suspender is initially tensioned;

[0102] Step 52, synchronous pushing and resetting of the middle cable saddle: for the asymmetric main cable arrangement, according to the design requirements, the middle cable saddle is synchronously pushed and reset during the installation of the middle main cable suspender; first, the offset amount Δ2 of the middle cable saddle is calculated according to the principle of constant unstressed length, and the change Δ3 of the offset amount of the middle cable saddle is considered during the pushing and resetting of the side cable saddle, and the side cable saddle is continuously reset during the installation of the middle suspender, and the resetting offset amount is Δ2+Δ3;

[0103] Step 53, installation of the side main cable permanent suspender and removal of the side main cable temporary suspender: after the preliminary tensioning of the middle main cable suspender and the pushing and resetting of the cable saddle are completed, the side main cable temporary suspender is gradually removed, the side main cable permanent suspender is installed, and the main cable line is further adjusted to make the main cable achieve the target line.

[0104] Step 6, remove the support, secondarily tension the main cable suspender, optimize the internal force of the bridge deck main body, and complete the construction of the main structure of the super-wide single-tower self-anchored suspension bridge.

[0105] The construction method adopts the construction method of first bridge deck main body and then cable, and the side main cable and the middle main cable are tensioned in batches, which avoids the problems of difficult control of the main cable and the bridge deck line of the suspension bridge, difficult segment splicing and closing of the bridge deck main body, and design difficulty of the multi-main cable spatial cable plane suspension bridge, and ensures the feasibility of the design and construction.

[0106] Application Example 2:

[0107] See Figure 3 , Figure 4The application discloses a super-wide single-tower self-anchored suspension bridge, which comprises a bridge deck body, a cable tower 6, main cables, a cable saddle 3 and a suspender 4. The bridge deck body adopts a split structure and comprises a stiffening beam 7 and a cross beam 8, the stiffening beam 7 and the cross beam 8 are fixedly connected to form the bridge deck body, and the bridge deck body serves as a working surface for bridge driving and the like; the cable tower 6 adopts a single-column cantilever structure, the bottom of the cable tower 6 is fixedly connected to the ground, and the top of the cable tower 6 is used for bearing the main cables 1; the main cables comprise two side main cables 1 and one middle main cable 2, the two side main cables are symmetrically arranged on the top of the cable tower 6 through the cable saddle 3 and are connected to the two ends of the cross beam 8 in the bridge deck body through side suspenders 4-1, and the middle main cable 2 is arranged in the middle of the top of the cable tower 6 through the cable saddle 3 and is connected to the middle of the cross beam 8 in the bridge deck body through a side suspender 4-2; the main cables are connected to the bridge deck body at the anchoring end 9 and are symmetrically arranged. The planar projection of the side main cable 1 is a symmetric curve, the curve is open to the outside, and the planar projection of the middle main cable 2 is a straight line. The main cables form a spatial multi-cable plane system, the torsional rigidity of the bridge is improved, and the wind stability is improved. The cable saddle 3 comprises two side cable saddles 3-1 and one middle cable saddle 3-2, the bottom of the cable saddle 3 is connected to the cable tower 6, the top of the cable saddle 3 is connected to the side main cable 1 and the middle main cable 2 respectively, and the cable saddle 3 serves as a bearing conversion component between the main cable 1 and the cable tower 6. The suspender 4 is used for connecting the main cable and the bridge deck body and is an important bearing transmission component of the suspension bridge.

[0108] Specifically, taking a certain symmetric super-wide single-tower self-anchored suspension bridge as an example, the span arrangement is 150+150=300m, the full width of the bridge deck is 50m, a conventional double-main-cable spatial cable plane suspension bridge is adopted, the calculation span of the cross beam 8 is 48.0m, and the design height of the cross beam needs to be 3.0m; the calculation span of the cross beam 8 of the three-main-cable spatial cable plane suspension bridge in the embodiment is 24.0m, the design height of the cross beam is 1.5m in consideration of the same height-span ratio, the height of the cross beam is significantly reduced. According to the design experience estimation, the steel consumption per square meter of the bridge deck body can be reduced by 350kg / m 2 The bridge deck body of the whole bridge can save the cost of about 75 million yuan; the beam height is reduced by 1.5m, the length of the two-side approach roads is reduced by 120m according to the conventional city road slope of 2.5%, and the engineering construction cost is saved by about 24 million yuan, which has a significant economic effect. Meanwhile, the cross beam 8 in the embodiment is a continuous beam structure in the transverse direction, and the vertical rigidity of the bridge deck body can be significantly improved.

[0109] The above merely describes the preferred embodiment of the application, and is not intended to limit the application, and any modification, equivalent replacement and improvement within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A self-anchored suspension bridge with a single tower and a deck width greater than 40 m, comprising a deck main body, a tower, and a saddle installed at the top of the tower for connecting a main cable, characterized in that: The bridge deck body adopts a split structure and comprises a stiffening beam and a cross beam, and the cross beam and the stiffening beam are fixedly connected to form the bridge deck body; The cable tower adopts a single-column cantilever structure, the bottom of the cable tower is fixedly connected to the ground, and the top of the cable tower is used for bearing the main cable; The main cable forms a spatial multi-cable plane system, the main cable comprises two side main cables and one middle main cable, the two side main cables are symmetrically installed on two sides of the top of the cable tower through cable saddles and are connected to two ends of the cross beam in the bridge deck body through side suspender rods, and the middle main cable is installed in the middle of the top of the cable tower through a cable saddle and is connected to the middle of the cross beam in the bridge deck body through a middle suspender rod, both ends of the main cable are anchored to the bridge deck body or the ground, the plane projection of the side main cable is a symmetric curve, the curve opening faces the inside, and the plane projection of the middle main cable is a straight line; The maximum stress of the cross beam is adjustable, and the specific design formula is: wherein is the bending modulus of the beam, is the transverse load on the beam, and are the top and bottom surfaces of the beam, respectively, due to the bending moment caused by the vertical deformation of the central boom, and L is the transverse distance between the left and right edge boom masts. The cable saddle comprises two side cable saddles and a middle cable saddle, the two side cable saddles are arranged on the outside, and the middle cable saddle is arranged between the two side cable saddles, and the saddle plate is connected to the cable tower.

2. The self-anchored suspension bridge with a single tower and a deck width greater than 40 m according to claim 1, characterized in that: The bridge deck body adopts a split steel box beam or a split steel truss beam.

3. The self-anchored suspension bridge with single tower and bridge deck width greater than 40 m according to claim 1, characterized in that: The two side main cables and the middle main cable constituting the main cable are asymmetrically arranged, and the side main cables and the middle main cable are anchored to the bridge deck body at the middle span end and are fixed to the ground at the side span.

4. The self-anchored suspension bridge with single tower and bridge deck width greater than 40 m according to claim 3, characterized in that: The two side cable saddles adopt an integral structure, and the side cable saddles and the middle cable saddle are adjustably fixed to the saddle plate.

5. The self-anchored suspension bridge with single tower and bridge deck width greater than 40 m according to claim 1, characterized in that: The two side main cables and the middle main cable constituting the main cable are symmetrically arranged, both ends of the side main cables and the middle main cable are anchored to the bridge deck body, the side cable saddles and the middle cable saddle constituting the cable saddle adopt an integral structure, and the top of the cable tower is fixedly connected.

6. The self-anchored suspension bridge with single tower and bridge deck width greater than 40 m according to claim 4 or 5, characterized in that: The distance from the center of the middle cable saddle to the center of the two side cable saddles is equal.

7. A construction method of a single-pylon self-anchored suspension bridge with a deck width greater than 40 m according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: Step 1, constructing the cable tower; Step 2, erecting a support and arranging a temporary support at the bottom of the bridge deck body; Step 3, erecting the main cable; Step 31: installing the side cable saddles and the middle cable saddle on the top of the cable tower, determining the initial offset of the side cable saddle, determining the unstressed length of the side main cable, and erecting the side main cable to make the side main cable in an empty cable state; Step 32: determining the initial offset of the middle cable saddle, determining the unstressed length of the middle main cable, and erecting the middle main cable to make the middle main cable in an empty cable state; in steps 31 and 32, the balance equation of the main cable is: wherein is the main cable horizontal internal force, z denotes the vertical coordinate of the main cable, x represents the coordinate in the bridge axis direction, denotes the main cable unit length mass; In steps 31 and 32, the vertical coordinates of the main cable are determined by using a parabola method: wherein is the rise of the main cable, is the calculated span; Step 4, installing the temporary suspender rod of the side main cable; Step 41, side main cable shape conversion: temporary suspender rods are installed at a certain distance on both sides of the bridge deck body, the temporary suspender rods are used to connect the cross beam and the side main cable, the temporary suspender rods are used to temporarily change the direction of the side main cable, the side main cable is preliminarily changed from the empty cable state to the bridge state, the cable shape is checked, and the transverse offset and the transverse deflection angle of the main cable are checked; In step 41, the balance equation of the main cable is: wherein is the main cable horizontal internal force, y denotes the main cable transverse coordinate, x denotes the bridge axis direction coordinate, denotes the main cable unit length mass, denotes the main cable calculation section length along the bridge axis; Step 42, synchronous jacking and resetting of the side cable saddle: for asymmetric main cable arrangement, the side cable saddles are synchronously jacked and reset according to the design requirements; Step 5, installing the permanent suspender rod of the main cable and converting the shape; Step 51, installing the suspender rod of the middle main cable and preliminarily tensioning: installing the suspender rod of the middle main cable, connecting the main cable and the bridge deck body, and preliminarily tensioning the suspender rod of the main cable; Step 52, the middle saddle synchronous pushing reset: for asymmetric main cable arrangement, according to the design requirements, the middle cable saddle synchronous main cable jib installation pushing reset slip; Step 53, install the edge main cable permanent jib, remove the edge main cable temporary jib: after the initial tensioning of the middle main cable jib is completed and the saddle pushing is in place, gradually remove the edge main cable temporary jib, install the edge main cable permanent jib, and further adjust the main cable line shape so that the main cable achieves the target line shape; Step 6, remove the support, secondary tensioning of the main cable jib, optimize the internal force of the bridge deck main body, and complete the main structure construction of the super-wide single-tower self-anchored suspension bridge.

8. The construction method of a self-anchored suspension bridge with a single tower and a deck width greater than 40 m according to claim 7, characterized in that: Step 42, first calculate the offset Δ1 of the edge saddle according to the principle of constant unstressed length, so that the balance condition of the two sides of the edge main cable satisfies the unbalanced force of the balanced cable tower, and consider the influence of the middle saddle, the edge saddle is constantly reset during the temporary jib installation process.

9. The construction method of a self-anchored suspension bridge with a single tower and a deck width greater than 40 m according to claim 7, characterized in that: Step 52, first calculate the offset Δ2 of the middle saddle according to the principle of constant unstressed length, consider that the offset Δ3 of the middle saddle changes during the edge saddle pushing reset process, the edge saddle is constantly reset during the middle jib installation process, and the reset offset is Δ2+Δ3.

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