Back-pressure upside-down hanging supporting system for large-span cable-stayed bridge

Abstract

The utility model relates to a reverse-pressure inverted-hanging supporting system for a large-span cable-stayed bridge beam, and belongs to the technical field of bridge construction, the reverse-pressure inverted-hanging supporting system comprises a bridge, the bridge comprises a side-span main beam and an approach bridge main beam which are arranged at intervals in the bridge direction, and an auxiliary pier located between the side-span main beam and the approach bridge main beam; and the back pressure base is fixedly arranged on the auxiliary pier, and the back pressure base is used for supporting the approach bridge main beam on the auxiliary pier and pressing the side span main beam on the auxiliary pier. Therefore, the dead weight of the approach bridge main beam, the dead weight of the auxiliary pier and the pile foundation of the auxiliary pier and the anti-drawing friction force of the pile foundation can be utilized to balance the unbalanced load of the side mid-span main beam, the stability and safety of the main tower structure are improved, the overall stress state of the bridge is improved, and the requirement of the auxiliary pier for the bearing capacity of a soil layer is reduced. The asymmetric load can be balanced by using fewer materials and a simpler and more convenient construction mode, the structural rigidity is improved, the stress of the bridge tower is optimized, and the aesthetic property of the bridge is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge construction, in particular to a counter-pressure inverted support system for a large-span cable-stayed bridge. BACKGROUND

[0002] The cable-stayed bridge is a modern large-span bridge form, which has been widely used in the world due to its unique design and excellent performance. With the progress of material science and construction technology, the span of the cable-stayed bridge gradually increases to the kilometer level.

[0003] However, due to the complexity of navigation conditions or terrain, the length of the main span and the side span often differs greatly in the design of many bridges, which is extremely unfavorable to the stress and overall stability of the tower structure, and often requires the addition of counterweights on the side span girder.

[0004] In the related art, a spatial tower column cable-stayed opening bridge with publication number CN101298753A discloses a cable-stayed bridge system structure, a spatial double cable plane, and concentrated anchoring of the cable on the upper end of the main tower. The main girder in the tail cable area of the side span is provided with counterweights to ensure the balance of the structure after horizontal rotation. However, the counterweights increase the self-weight and material consumption of the structure, leading to complex construction and material waste, thereby increasing the construction difficulty and engineering cost. SUMMARY

[0005] To address one or more of the deficiencies in the background art, embodiments of the present application provide a counter-pressure inverted support system for a large-span cable-stayed bridge to improve the overall stiffness and stability of the large-span cable-stayed bridge and balance the asymmetric load of the side and middle spans.

[0006] Embodiments of the present application provide a counter-pressure inverted support system for a large-span cable-stayed bridge, comprising:

[0007] A bridge, comprising a side span girder and an approach girder arranged at intervals along the bridge direction, and an auxiliary pier between the side span girder and the approach girder;

[0008] A counter-pressure base fixedly arranged on the auxiliary pier, the counter-pressure base being used to support the approach girder on the auxiliary pier and to press the side span girder down on the auxiliary pier to balance the unbalanced load of the side and middle span girders.

[0009] In some embodiments, the counter-pressure base comprises an L-shaped member and a cantilever member connected to each other, the L-shaped member being fixed on the auxiliary pier and used to support the approach girder, and the cantilever member being used to press the side span girder down.

[0010] In some embodiments, the counter-pressure base is a box-shaped steel member, the inside of the box-shaped steel member is filled with concrete, and the outside of the box-shaped steel member is wrapped with a concrete layer.

[0011] In some embodiments, the cantilever member is provided with a first sensor for monitoring stress near one end of the L-shaped member, and a second sensor for monitoring pressure between the cantilever member and the approach main beam.

[0012] In some embodiments, a positive pressure support is arranged between the counter-pressure base and the approach main beam, and a counter-pressure support is arranged between the counter-pressure base and the side span main beam, and the pressure directions of the positive pressure support and the counter-pressure support are opposite.

[0013] In some embodiments, the positive pressure support and the counter-pressure support are any one of a pot-type rubber support, a plate-type rubber support, a spherical steel support, and a tension-compression support.

[0014] In some embodiments, the top surface of the side span main beam is flush with the top surface of the counter-pressure base, and the side span main beam is provided with a first corbel for the counter-pressure base to press down near one end of the approach main beam.

[0015] In some embodiments, the top surface of the approach main beam is flush with the top surface of the counter-pressure base, and the approach main beam is provided with a second corbel near one end of the side span main beam, and the counter-pressure base is provided with a groove for extending into the second corbel.

[0016] In some embodiments, the counter-pressure base extends along the transverse direction of the bridge and is located between the side span main beam and the approach main beam, and the side span main beam and the approach main beam are both formed with expansion joints with the counter-pressure base.

[0017] In some embodiments, the auxiliary pier includes a pier body fixedly connected with the counter-pressure base, and a pile foundation fixedly connected with the pier body, and the pile foundation is a friction-type pile foundation.

[0018] The technical scheme provided in the application has the following beneficial effects:

[0019] The embodiment of the application provides a counter-pressure inverted support system for a large-span cable-stayed bridge, the bridge includes a side span main beam and an approach main beam which are arranged at intervals along the longitudinal direction of the bridge, and an auxiliary pier located between the side span main beam and the approach main beam; and a counter-pressure base, the counter-pressure base is fixedly arranged on the auxiliary pier, and the counter-pressure base is used for supporting the approach main beam on the auxiliary pier and for pressing down the side span main beam on the auxiliary pier.

[0020] Therefore, the stability and safety of the main tower structure can be improved, the overall stress state of the bridge can be improved, and the bearing capacity requirement of the auxiliary piers on the soil layer can be reduced by balancing the unbalanced load of the side span main girder with the self-weight of the approach bridge main girder, the self-weight of the auxiliary piers and the pile foundations, and the tensile friction resistance of the pile foundations. Especially in the construction of the side span and the middle span asymmetric cable-stayed bridge, the asymmetric load can be balanced, the structural rigidity can be improved, the stress of the bridge tower can be optimized, the bridge aesthetics can be improved, the complex terrain can be adapted, and the construction convenience can be provided by using less material and a simpler construction method. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0022] Figure 1 The structural schematic diagram of the counter-pressure inverted support system of the embodiment of the present application is shown in the figure.

[0023] Figure 2 The structural schematic diagram of the counter-pressure base of the embodiment of the present application is shown in the figure.

[0024] In the drawings, the components represented by the numbers are listed as follows:

[0025] 1, side span main girder; 11, first corbel; 2, approach bridge main girder; 21, second corbel; 3, auxiliary pier; 31, pier body; 32, pile foundation; 4, counter-pressure base; 41, L-shaped component; 42, cantilever component; 5, positive pressure support; 6, counter-pressure support; 7, stay cable; 8, main tower; 9, middle span main girder. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application.

[0027] In view of the deficiencies of the above background art or one of the deficiencies, the counter-pressure inverted support system for the long-span cable-stayed bridge is provided to improve the overall rigidity and stability of the long-span cable-stayed bridge and balance the asymmetric load of the side span and the middle span.

[0028] Referring to Figure 1 and Figure 2As shown, the embodiment of the present application provides a counter-pressure inverted hanging support system for a long-span cable-stayed bridge, comprising:

[0029] A bridge, the bridge comprising a side span main girder 1 and an approach main girder 2 arranged at intervals along the bridge direction, and an auxiliary pier 3 located between the side span main girder 1 and the approach main girder 2;

[0030] A counter-pressure base 4 fixedly arranged on the auxiliary pier 3, the counter-pressure base 4 being used to support the approach main girder 2 on the auxiliary pier 3, and to press the side span main girder 1 down on the auxiliary pier 3 to balance the unbalanced load of the side span main girder.

[0031] The counter-pressure inverted hanging support system for a long-span cable-stayed bridge of the embodiment of the present application utilizes the self-weight of the approach main girder 2, the self-weight of the auxiliary pier 3 and its pile foundation 32, and the pull-out friction resistance of the pile foundation 32 to balance the unbalanced load of the side span main girder, improve the stability and safety of the main tower 8 structure, improve the overall stress state of the bridge, and reduce the bearing capacity requirement of the auxiliary pier 3 on the soil layer. Especially in the construction of the asymmetric cable-stayed bridge, the asymmetric load is balanced, the structural rigidity is improved, the stress of the bridge tower is optimized, the bridge aesthetics is improved, the complex terrain is adapted, and the construction convenience is provided by using less material and a simpler construction method. The main functions are as follows:

[0032] 1. The load of the side span can be balanced. In a cable-stayed bridge, the main span is usually longer, and the side span is shorter. If no balancing measures are taken, the load of the main span will cause the bridge tower to tilt to the main span side, resulting in uneven stress on the structure. The counter-pressure inverted hanging support system balances the load on both sides of the bridge tower by setting the counter-pressure support 6 on the top of the auxiliary pier 3, and transferring part of the load of the main span to the side span, so that the bridge tower remains in a vertical state.

[0033] 2. The stress of the bridge tower can be improved. The bridge tower bears huge vertical and horizontal loads in a cable-stayed bridge, especially in the case of asymmetric side span and main span, the bending moment and shear force of the bridge tower will increase significantly. The counter-pressure inverted hanging support system balances the tension of the side span cable-stayed cable 7 by the self-weight of the approach main girder 2, the auxiliary pier 3 and its pile foundation 32 through the counter-pressure support 6, reduces the bending moment and shear force of the bridge tower, optimizes the stress state of the bridge tower, and reduces the design difficulty and material consumption of the bridge tower.

[0034] 3. The stress of the bridge deck can be optimized. The bridge deck of a cable-stayed bridge will produce a large bending moment and shear force under load, especially in the case of asymmetric side span and main span. The counter-pressure inverted hanging support system improves the stress state of the bridge deck by the pressure of the counter-pressure support 6, reduces the bending moment and shear force of the bridge deck, and improves the carrying capacity of the bridge deck.

[0035] 4、Can improve the structural stiffness. The cable-stayed bridge is easy to produce large deformation and vibration under the action of dynamic load such as wind load and seismic load. The counter-pressure support 6 of the counter-pressure inverted support system does not have the risk of emptying, can effectively constrain the side span main beam 1, improve the overall stiffness of the bridge, reduce the deformation and vibration, and enhance the wind resistance and seismic performance of the bridge.

[0036] For example, the counter-pressure inverted support system of the embodiment of the application is composed of a cable-stayed bridge main structure, an auxiliary pier 3 and a counter-pressure base 4. The cable-stayed bridge main structure is composed of a bridge tower, a stay cable 7, a side span main beam 1 and a mid-span main beam 9. The auxiliary pier 3 is located at the edge of the side span of the cable-stayed bridge and is used to bear and transfer the load of the side span part of the cable-stayed bridge.

[0037] The counter-pressure base 4 is placed above the auxiliary pier 3 and is designed to be concave on the side. The bottom of the counter-pressure base 4 is fixed with the auxiliary pier 3, and the upper inner surface of the concave part is used to install the counter-pressure support 6. The upper surface of the side wall of the counter-pressure base 4 is partially excavated to form a platform to place the normal-pressure support 5 for supporting the approach bridge main beam 2.

[0038] The counter-pressure support 6 is hung upside down on the upper inner surface of the concave part of the counter-pressure base 4 and is supported at the end of the side span main beam 1 of the cable-stayed bridge. The counter-pressure support 6 mainly bears the unbalanced load of the side and mid-span main beams 9 and transfers it to the counter-pressure base 4. The bearing capacity of the counter-pressure support 6 is determined according to the weight difference between the side span and the mid-span and the load difference during operation.

[0039] It should be noted that the force transmission path of a general cable-stayed bridge is: the load of the main beam is transmitted to the bridge tower through the stay cable, and then to the pile foundation through the bridge tower. The remaining small part of the load of the side span is transmitted to the pile foundation through the side span auxiliary pier, and the bridge tower and the side pier support provide longitudinal and transverse constraints.

[0040] However, due to the asymmetry of the side and mid-span main beams of the long-span cable-stayed bridge, the self-weight of the mid-span main beam is much greater than that of the side span main beam. Therefore, the bridge tower will be inclined and bent under the action of the unbalanced load, and an upward tension will be generated on the side span main beam through the stay cable.

[0041] The counter-pressure inverted support system provided by the application ingeniously utilizes the self-weight of the auxiliary pier 3 and the friction force between the pile foundation 32 and the soil layer to provide downward force, which not only balances the load of the side and mid-span main beams, but also saves the counterweight material of the side span main beam 1 and reduces the self-weight of the structure itself.

[0042] At the same time, the self-weight of the approach bridge main beam 2 exerts a pressure on the side span main beam 1 through the counter-pressure base 4, which ingeniously utilizes the self-weight of the approach bridge main beam 2 to provide downward force to balance the load of the side and mid-span main beams 9 without affecting the safety of the bridge, thereby reducing the requirement for the friction force between the self-weight of the auxiliary pier 3 and the pile foundation 32 and the soil layer, saving construction materials and shortening the construction period.

[0043] In some optional embodiments: see Figure 1and Figure 2 As shown in The anti-pressure base 4 of the anti-pressure inverted hanging support system for the long-span cable-stayed bridge provided by the embodiment of the present application comprises an L-shaped component 41 and a cantilever component 42 which are connected to each other, the L-shaped component 41 is fixed on the auxiliary pier 3 and is used to support the approach bridge main beam 2, and the cantilever component 42 is used to press down the side span main beam 1.

[0044] The L-shaped component 41 and the cantilever component 42 of the embodiment of the present application are integrally arranged, the L-shaped component 41 increases the butt joint surface with the auxiliary pier 3, in order to avoid the anti-pressure base 4 being pulled and warped, the bottom surface of the L-shaped component 41 is fixed on the top of the auxiliary pier 3 through the anti-pulling rivets, the cantilever component 42 extends towards the side span main beam 1 and does not exceed the auxiliary pier 3, which facilitates pressing down the approach bridge main beam 2. Exemplarily, the cantilever component 42 is a gradually changing cross section, such as a fish belly shape, which can reduce stress concentration and improve bending stiffness.

[0045] In some optional embodiments, referring to Figure 1 and Figure 2 As shown in The anti-pressure base 4 of the anti-pressure inverted hanging support system for the long-span cable-stayed bridge provided by the embodiment of the present application is a box-shaped steel component, the inside of the box-shaped steel component is filled with concrete, and the outer surface of the box-shaped steel component is wrapped with a concrete layer.

[0046] The anti-pressure base 4 of the embodiment of the present application is a box-shaped steel component, the cross section of the box-shaped steel component is a rectangular or square hollow cross section, which has good torsional performance and can adapt to complex stress conditions, the internal cavity of the box-shaped steel component is filled with high-strength concrete, and at the same time, the outer surface is wrapped with a concrete layer formed by hardening of high-strength concrete, which can further improve the compression resistance, bending resistance and torsional resistance, so that the overall bearing capacity is significantly improved, and the anti-pressure inverted hanging support system is suitable for the complex stress scenarios with high load and large span in the present application.

[0047] In some optional embodiments, referring to Figure 1 and Figure 2 As shown in The anti-pressure inverted hanging support system for the long-span cable-stayed bridge provided by the embodiment of the present application, the cantilever component 42 is provided with a first sensor for monitoring stress at one end close to the L-shaped component 41, and a second sensor for monitoring pressure is arranged between the cantilever component 42 and the approach bridge main beam 2.

[0048] Exemplarily, the cantilever component 42 of the embodiment of the present application is integrally arranged with the L-shaped component 41, the first sensor (not shown in the figure) is installed at the root of the cantilever component 42 close to the L-shaped component 41 (which is the region with the maximum bending moment), the first sensor can adopt a fiber grating sensor, which is embedded on the cantilever component 42 to monitor stress, strain and temperature change in real time.

[0049] A second sensor (not shown in the figure) is also installed between the cantilever member 42 and the approach bridge main girder 2, which can be a piezoelectric sensor such as a piezoelectric ceramic sensor or a piezoelectric film, which can monitor the counter pressure on the counter pressure base 4 in real time. Finally, the data from the first sensor and the second sensor can be transmitted wirelessly to the external central monitoring system to achieve remote real-time monitoring and early warning.

[0050] Specifically, in some embodiments, the first sensor is a fiber Bragg grating sensor, and the number of fiber Bragg grating sensors is three, which are arranged at the upper surface, the lower surface and the neutral axis position of the root of the cantilever member 42 (the connection between the cantilever member 42 and the L-shaped member 41) along the length direction of the cantilever member 42, respectively, to monitor the strain distribution of tension, compression and neutral layer, respectively. The fiber Bragg grating sensor is fixed on the surface of the cantilever member 42 by spot welding or epoxy resin, and is covered with a stainless steel sheath to prevent construction damage.

[0051] The fiber Bragg grating demodulator (such as MOI SM130) is used to scan the reflection wavelength change of the fiber Bragg grating sensor in real time, a plurality of fiber Bragg grating sensors are connected in series through a fiber splitter, the fiber signal is transmitted to the data acquisition station of the bridge tower or abutment through the pre-embedded optical cable on the bridge deck, and the data is uploaded to the cloud platform in real time for real-time monitoring and abnormal early warning.

[0052] By monitoring the strain distribution at the root of the cantilever in real time, it can be judged whether the cantilever member 42 is overloaded or local buckling occurs. For example, when the strain exceeds 80% of the design value, an alarm is triggered to prompt the inspection of structural damage. Fatigue damage can also be evaluated through the strain time history curve to predict the remaining life.

[0053] Specifically, in some embodiments, the second sensor is a piezoelectric film, and the counter pressure support 6 between the cantilever member 42 and the approach bridge main girder 2 is a spherical support. The piezoelectric film is arranged between the upper support plate and the sliding plate of the spherical support (which is a dynamic pressure fluctuation area), and is cut into a strip shape matching the sliding surface, adhered to the surface of the sliding plate through conductive adhesive, and covered with a protective layer (such as a polyimide film) to prevent mechanical wear.

[0054] The charge signal output by the PVDF is converted into a voltage signal through a charge amplifier, and the amplified signal is input into a data acquisition card. The dynamic sampling frequency is set to be greater than or equal to 1 kHz to capture the transient fluctuation of the contact pressure. A low-pass filter is used to eliminate high-frequency noise and extract the effective pressure signal. The data can be recorded synchronously with the fiber Bragg grating sensor described above, and the load and strain response can be analyzed in association.

[0055] By monitoring the pressure distribution of the sliding interface in real time, it is determined whether the support is off-loaded or locally empty. If the pressure peak value exceeds the design value or is unevenly distributed, it indicates that the support lubrication has failed or the installation is deviated. At the same time, combined with the vehicle load data, the dynamic response of the support under the action of live load can be analyzed, and the bridge operation management can be optimized.

[0056] It should be noted that the fiber Bragg grating sensor can be accurately arranged at the root of the cantilever member 42 to monitor the bending and shear strain in real time and prevent structural damage. The piezoelectric film is installed at the sliding interface of the support to dynamically capture the contact pressure fluctuation and optimize the maintenance strategy. The combination of the two data provides a full life cycle health monitoring for the cable-stayed bridge. The synergistic effect of the two can realize the transition from "passive maintenance" to "active early warning", and significantly improve the safety and durability.

[0057] In some optional embodiments: referring to Figure 1 and Figure 2 The anti-pressure inverted hanging support system for the long-span cable-stayed bridge provided by the embodiments of the present application is provided with a positive pressure support 5 between the anti-pressure base 4 and the approach bridge main beam 2, and an anti-pressure support 6 between the anti-pressure base 4 and the side span main beam 1. The pressure directions of the positive pressure support 5 and the anti-pressure support 6 are opposite.

[0058] The second bracket 21 of the approach bridge main beam 2 and the L-shaped member 41 of the anti-pressure base 4 are provided with the positive pressure support 5, which is used to bear the vertical pressure generated by the approach bridge main beam 2 under the action of dead load and live load, and at the same time, adapt to the horizontal displacement of the approach bridge main beam 2 (such as temperature deformation, displacement caused by live load, etc.). The support stability of the approach bridge main beam 2 can be improved.

[0059] At the same time, the cantilever member 42 of the anti-pressure base 4 and the first bracket 11 of the side span main beam 1 are provided with the anti-pressure support 6, which is used to bear the upward force and can always be in a pressure state. It can adapt to the complex stress state of the side span main beam 1 under the action of alternating tension and compression load, and ensure that the bridge can work normally under various working conditions.

[0060] In some optional embodiments: referring to Figure 1 and Figure 2 The anti-pressure inverted hanging support system for the long-span cable-stayed bridge provided by the embodiments of the present application is provided with a positive pressure support 5 and an anti-pressure support 6, which are any one of a pot-type rubber support, a plate-type rubber support, a spherical steel support and a tension-compression support.

[0061] The positive pressure support 5 of the embodiment of the application adopts a pot-type rubber support, which is composed of a steel pot, a rubber pad and an upper support plate. The rubber pad provides elastic deformation capacity, and the steel pot limits lateral displacement. The positive pressure support 5 has strong bearing capacity (up to several thousand tons) and is suitable for supporting the main girder of a large-span cable-stayed bridge. The positive pressure support 5 has good vertical stiffness and horizontal displacement adaptability. The positive pressure support 5 has high durability and low maintenance cost. The positive pressure support 5 can be used to bear the vertical pressure generated by the dead load and live load of the approach girder main girder 2 and simultaneously allow certain horizontal displacement (such as temperature deformation).

[0062] Further, a polytetrafluoroethylene (PTFE) sliding layer can be additionally arranged between the rubber pad and the upper support plate to reduce the friction coefficient (μ≤0.03) and improve the horizontal displacement capacity. Or, a lead core or high-damping rubber is arranged in the steel pot to enhance the energy dissipation capacity of the support and adapt to seismic load.

[0063] The counter-pressure support 6 of the embodiment of the application adopts a spherical steel support, which is composed of an upper support plate, a spherical sliding pair and a lower support plate. The spherical sliding pair allows multi-directional rotation and displacement. The counter-pressure support 6 can adapt to complex stress states (such as alternating tensile and compressive load). The counter-pressure support 6 rotates flexibly and can effectively release the local bending moment of the main girder. The counter-pressure support 6 has good durability and is suitable for long-term bearing of dynamic load. The counter-pressure support 6 can be used to bear the upward force (negative counter-force) that may be generated by the side span main girder 1 and simultaneously adapt to the rotation and horizontal displacement of the side span main girder 1.

[0064] Further, a shape memory alloy SMA or spring device can be embedded in the spherical sliding pair to automatically reset the support after unloading, reduce residual deformation and realize the self-resetting function. Or, a rigid stopper is additionally arranged at the top of the support to fix the connection of the counter-pressure base 4 and limit excessive displacement under extreme wind load.

[0065] In some optional embodiments, as shown in Figure 1 and Figure 2 The counter-pressure inverted support system for the long-span cable-stayed bridge beam provided by the embodiment of the application has a top surface of the side span main girder 1 flush with a top surface of the counter-pressure base 4. The side span main girder 1 is provided with a first corbel 11 for the counter-pressure base 4 to press downward.

[0066] The counter-pressure base 4 of the embodiment of the application balances the unbalanced load of the side span main girder by pressing downward on the first corbel 11 of the side span main girder 1. The arrangement of the first corbel 11 makes the top surface of the side span main girder 1 flush with the top surface of the counter-pressure base 4, which simplifies the construction method and improves the aesthetic appearance of the bridge.

[0067] In some optional embodiments, as shown in Figure 1 and Figure 2As shown, the embodiment of the present application provides a reverse pressure inverted support system for a large-span cable-stayed bridge, the top surface of the approach bridge main girder 2 is flush with the top surface of the reverse pressure base 4, the approach bridge main girder 2 is provided with a second corbel 21 near one end of the side span main girder 1, and the reverse pressure base 4 is provided with a groove for extending into the second corbel 21.

[0068] The reverse pressure base 4 of the embodiment of the present application supports the first corbel 11 of the approach bridge main girder 2, realizes stable support of the approach bridge main girder 2, so that the top surface of the approach bridge main girder 2 can be flush with the top surface of the reverse pressure base 4, the construction method is simple, and the bridge aesthetics is improved.

[0069] In some optional embodiments, referring to Figure 1 and Figure 2 As shown, the embodiment of the present application provides a reverse pressure inverted support system for a large-span cable-stayed bridge, the reverse pressure base 4 of the reverse pressure inverted support system for a large-span cable-stayed bridge is arranged along the transverse bridge direction and located between the side span main girder 1 and the approach bridge main girder 2, and the side span main girder 1 and the approach bridge main girder 2 are both formed with expansion joints with the reverse pressure base 4.

[0070] The expansion joints formed between the side span main girder 1 and the reverse pressure base 4, and between the reverse pressure base 4 and the approach bridge main girder 2 of the embodiment of the present application can adapt to the deformation of the side span main girder 1 and the approach bridge main girder 2 due to temperature changes, concrete shrinkage and live load effects, thereby ensuring the safety of the bridge structure.

[0071] In some optional embodiments, referring to Figure 1 and Figure 2 As shown, the embodiment of the present application provides a reverse pressure inverted support system for a large-span cable-stayed bridge, the auxiliary pier 3 of the reverse pressure inverted support system for a large-span cable-stayed bridge includes a pier body 31 fixedly connected with the reverse pressure base 4, and a pile foundation 32 fixedly connected with the pier body 31, and the pile foundation 32 is a friction type pile foundation.

[0072] The side span main girder of the embodiment of the present application has a large unbalanced load, in order to avoid the reverse pressure base 4 being pulled and warped, a tensile steel nail is added to the bottom surface of the reverse pressure base 4 and the top of the auxiliary pier 3 to strengthen the connection and improve the tensile resistance of the base.

[0073] In addition, in order to improve the tensile resistance of the reverse pressure inverted support system, the pile foundation 32 of the auxiliary pier 3 is arranged as a friction type pile foundation, and the tensile resistance is provided by the friction force of the pile foundation 32 and the surrounding soil layer.

[0074] For example, the self-weight of the mid-span main girder 9 is defined as G Z , the self-weight of the side span main girder 1 is G B , the self-weight of the auxiliary pier 3 is G F , and the tensile resistance friction of the pile foundation 32 of the auxiliary pier 3 is FF , the force of the counter-pressure support 6 is F, and the maximum support counter-force that it can provide is F max , k is a safety factor. According to the basic principle of force balance in structural mechanics;

[0075] F = G Z -G B

[0076] Therefore, the design of the counter-pressure support 6 of the counter-pressure inverted support system should satisfy:

[0077] F max ≥ k(G Z -G B )

[0078] When G F ≥ k(G Z -G B ), F F can be designed according to the normal bridge pile foundation bearing capacity design;

[0079] When G F < k(G Z -G B ), F F needs to consider the anti-pulling, and in addition to satisfying the normal bridge pile foundation bearing capacity design, G F +F F ≥ k(G Z -G B ) should also be satisfied.

[0080] Among them, the anti-pulling friction force F F of the pile foundation is determined according to the anti-pulling coefficient λ of the friction type pile foundation. The anti-pulling coefficient λ of the friction type pile foundation is the ratio of the pile foundation anti-pulling bearing capacity to the anti-pressure side friction resistance, reflecting the difference of the pile-soil interface in the tensile and compressive states. The value range is usually 0.5-0.8. According to the “Highway Bridge and Culvert Foundation and Foundation Design Specification” JTG 3363-2019, the single pile anti-pulling bearing capacity formula is:

[0081] T d = Σλ i q sik μ i l i

[0082] T d is the single pile anti-pulling bearing capacity design value; λ i is the anti-pulling coefficient of the i-th layer of soil; q sik is the anti-pressure side friction resistance standard value of the i-th layer of soil; μ i is the circumference of the pile; l i is the pile length of the i-th layer of soil.

[0083] The λ of the prefabricated pile in general sandy soil layer can be 0.6; and the λ of the cast-in-place pile in clay can be 0.75.

[0084] That is, when the auxiliary pier 3 is located in a region with poor soil layer, the foundation bearing capacity thereof is insufficient to bear the load transmitted by the bridge structure, at this time, the upward pulling force generated by the unbalanced load of the side mid-span main girder 9 can offset a part of the force transmitted by the superstructure, the auxiliary pier 3 and the pile foundation 32 to the soil layer, thereby reducing the foundation bearing capacity requirement of the auxiliary pier 3, improving the construction convenience greatly, and achieving the economic and aesthetic effects.

[0085] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication of two elements. 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.

[0086] It should be noted that in the present application, relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0087] The above description is only a specific embodiment of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A counter pressure inverted support system for long span cable-stayed bridges, characterized in that, Comprise: a bridge comprising a side span girder (1) and an approach girder (2) arranged at intervals along the bridge direction, and a auxiliary pier (3) between the side span girder (1) and the approach girder (2); a counter pressure base (4) fixedly arranged on the auxiliary pier (3), the counter pressure base (4) is used for supporting the approach girder (2) on the auxiliary pier (3), and is used for pressing the side span girder (1) on the auxiliary pier (3) to balance the unbalanced load of the side span girder.

2. The counter pressure inverted support system for long-span cable-stayed bridge of claim 1, wherein: the counter pressure base (4) comprises an L-shaped member (41) and a cantilever member (42) connected with each other, the L-shaped member (41) is fixed on the auxiliary pier (3) and is used for supporting the approach girder (2), and the cantilever member (42) is used for pressing the side span girder (1).

3. The counter pressure inverted support system for long-span cable-stayed bridge of claim 1 or 2, wherein: the counter pressure base (4) is a box-shaped steel member, the inside of the box-shaped steel member is filled with concrete, and the outside of the box-shaped steel member is wrapped with a concrete layer.

4. The counter pressure inverted support system for long-span cable-stayed bridge of claim 2, wherein: the cantilever member (42) is provided with a first sensor for monitoring stress near one end of the L-shaped member (41), and a second sensor for monitoring pressure between the cantilever member (42) and the approach girder (2).

5. The counter pressure inverted support system for long-span cable-stayed bridge of claim 1, wherein: a positive pressure support (5) is arranged between the counter pressure base (4) and the approach girder (2), and a counter pressure support (6) is arranged between the counter pressure base (4) and the side span girder (1), and the pressure directions of the positive pressure support (5) and the counter pressure support (6) are opposite.

6. The counter pressure inverted support system for long-span cable-stayed bridge of claim 5, wherein: the positive pressure support (5) and the counter pressure support (6) are any one of a pot rubber support, a plate rubber support, a spherical steel support, and a tension-compression support.

7. The counter pressure inverted support system for long-span cable-stayed bridge of claim 1, wherein: the top surface of the side span girder (1) is flush with the top surface of the counter pressure base (4), and the side span girder (1) is provided with a first corbel (11) for the counter pressure base (4) to press near one end of the approach girder (2).

8. The counter pressure inverted support system for long-span cable-stayed bridge of claim 1, wherein: the top surface of the approach girder (2) is flush with the top surface of the counter pressure base (4), and the approach girder (2) is provided with a second corbel (21) near one end of the side span girder (1), and the counter pressure base (4) is provided with a groove for extending into the second corbel (21).

9. The counter pressure inverted support system for long-span cable-stayed bridge of claim 1, wherein: The counter-pressure base (4) is arranged between the side span girder (1) and the approach girder (2) in the transverse direction and is connected with the side span girder (1) and the approach girder (2) by expansion joints.

10. The counter-pressure inverted support system for long-span cable-stayed bridges according to claim 1, characterized in that: The auxiliary pier (3) comprises a pier body (31) fixedly connected with the counter-pressure base (4), and a pile foundation (32) fixedly connected with the pier body (31), wherein the pile foundation (32) is a friction type pile foundation.

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