Construction method of a cable-stayed-continuous collaborative system composite beam bridge

Abstract

The present invention relates to the technical field of bridge construction, and provides a construction method for a cable-stayed continuous collaborative system composite beam bridge. The method does not require the arrangement of a large number of prestressed corrugated pipes and steel bundles to ensure the performance of a bridge deck, and fully utilizes the structural characteristics of the cable-stayed continuous collaborative system composite beam bridge itself. By changing the overlapping sequence of the continuous composite beam bridge deck, it is ensured that the bridge deck in the negative bending moment area of ​​the continuous composite beam does not generate tensile stress, while the bridge deck in the positive bending moment area generates compressive stress reserve. By increasing the tension of the cable-stayed cable, the continuous composite beam is displaced upward near the main beam on the side of the cable-stayed bridge, and the main beam on the side of the side span is displaced downward, so that the bridge deck generates compressive stress and the steel main beam generates tensile stress, and the compressive performance of the concrete material and the tensile performance of the steel material are fully utilized, thereby improving the material utilization rate. The pre-compressive stress of the bridge deck is completed by distributing the internal force of the composite beam itself. The construction method is simple and operable, and the structural stress is clear, thereby ensuring the rationality and safety of the structural stress.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a construction method of a cable-stayed-continuous cooperative system composite beam bridge. Background Art

[0002] With the development of economy and bridge technology, the construction of long-span bridges in highways and municipal engineering is increasing. Among them, steel-concrete composite beam cable-stayed bridges are favored by designers and builders because they make full use of the tensile properties of steel and the compressive properties of concrete, and have large span capacity and beautiful appearance. However, as the span of the cable-stayed bridge increases, the stability of the cable-stayed bridge will decrease, and the height of the main tower, the height of the main beam and the length of the cable-stayed cable will increase, and its construction cost will also increase. The cable-stayed-continuous collaborative system composite beam bridge comprehensively utilizes the structural characteristics of the cable-stayed bridge and the continuous beam bridge as well as the performance of steel and concrete materials. It can not only increase the span capacity and improve the stability of the bridge, but also reduce the cost of the cable-stayed bridge. As a novel bridge structure, it has been used in more and more bridge construction.

[0003] For continuous composite beams, the bridge deck in the pier top area will produce large tensile stress under the combined action of the structure's deadweight load, the live load of vehicles in the operational state after the bridge is completed, temperature load, support point settlement, etc., and its tensile range will also increase with the increase of span. When the tensile stress exceeds the tensile strength of the concrete material, it will cause the bridge deck to crack, and the cross-sectional characteristics and bearing capacity will be weakened, thus affecting the safety and durability of the structure. It is necessary to apply prestress to the bridge deck at the top of the continuous beam pier to ensure its performance.

[0004] The traditional construction method of prestressed bridge decks is to reserve prestressed pipes in the bridge deck and then tension prestressed steel strands to increase the compressive stress of the bridge deck. However, this construction method requires reserved pipes, which will reduce the characteristics of the concrete section and affect the construction quality of the bridge deck. In addition, since the prestress is applied after the bridge deck and the steel beam are superimposed, a large part of the prestress will be borne by the steel beam, and the bridge deck can only be allocated to a small part of the prestress. Therefore, a large number of prestressed steel strands are required to ensure that the prestress of the bridge deck is sufficient. The economy is poor and the construction is complicated. In addition, as the span of the cable-stayed-continuous system increases, the tensile stress of the continuous pier top will also increase. The construction method of applying prestressed steel strands to apply prestressed stress may not meet its prestressed stress requirements, thereby limiting the further development of the cable-stayed-continuous collaborative system composite beam bridge.

[0005] In view of this, it is necessary to propose a construction method for a cable-stayed-continuous collaborative system composite beam bridge to solve or at least alleviate the above-mentioned defects. Summary of the invention

[0006] The main purpose of the present invention is to provide a construction method for a cable-stayed-continuous cooperative system composite beam bridge, so as to solve the problem that the bridge deck of the continuous composite beam of the cable-stayed-continuous cooperative system composite beam bridge in the prior art increases the compressive stress of the bridge deck by tensioning prestressed steel strands to ensure its performance. This method requires a large number of prestressed steel strands to ensure sufficient pre-compressive stress of the bridge deck, has poor economy and complex construction.

[0007] To achieve the above object, the present invention provides a construction method of a cable-stayed-continuous cooperative system composite beam bridge, comprising the steps of:

[0008] S1, constructing the first steel beam segment of the continuous composite beam on the support step by step to the maximum cantilever state, hoisting the first bridge deck and reserving the first wet joint between two adjacent first bridge decks;

[0009] S2, cantilever construction of the second steel beam segment and the second bridge deck of the cable-stayed bridge composite beam to the maximum cantilever state, and reserve a second wet joint between two adjacent second bridge decks;

[0010] S3, casting all the first wet joints located in the first positive bending moment zone, not casting the first wet joints located in the first negative bending moment zone for the time being, and removing the support to allow the first steel beam segment to move downward; wherein the continuous composite beam includes the first negative bending moment zone and the first positive bending moment zone away from the composite beam of the cable-stayed bridge after the support is removed;

[0011] S4, hoisting the steel beam of the joint section, completing the connection and jointing of the continuous composite beam and the composite beam of the cable-stayed bridge, hoisting the bridge deck of the joint section, and reserving a third wet joint between the bridge deck of the joint section and the first bridge deck, and reserving a fourth wet joint between the bridge deck of the joint section and the second bridge deck, and then casting the third wet joint, the fourth wet joint and all the first wet joints in the second positive bending moment zone in this structural state, and the first wet joints located in the second negative bending moment zone are not cast for the time being;

[0012] S5, casting the first wet joint located in the second negative bending moment zone, and starting from the side close to the second positive bending moment zone, sequentially tensioning multiple inclined cables to the design value, so that after tensioning, the bridge pier located at the first steel beam segment close to the joint section steel beam side of the continuous composite beam is displaced upward, and the bridge pier located at the first steel beam segment away from the joint section steel beam side of the continuous composite beam is displaced downward.

[0013] Preferably, the design value in step S5 is obtained by the following steps:

[0014] S51, when the first bridge deck does not consider the prestressing construction measures, the tensile stress distribution of the first bridge deck, and determine the size and range of the prestressing stress required to be applied to the first bridge deck when meeting the anti-cracking requirements of the specification according to the tensile stress distribution;

[0015] S52, obtaining the maximum tensile stress of the first bridge deck according to the tensile stress distribution, and taking the cross section corresponding to the maximum tensile stress as the target control cross section;

[0016] S53, obtaining the compressive stress reserve required for the target control section to meet the design conditions, and taking the difference between the maximum tensile stress corresponding to the target control section and the compressive stress reserve as the compressive stress target value σ to be applied to the first bridge deck 总 ;

[0017] S54, obtaining a tensile stress reduction value σ1 of the first bridge deck located in the second negative bending moment area after the first wet joint located in the second negative bending moment area is cast and cured in step S5;

[0018] S55, determining the compressive stress target value σ 总 The difference between the tensile stress reduction value σ1 and the compressive stress target value σ2 required for cable tensioning is obtained;

[0019] S56, taking the first wet joint located in the second negative moment area after casting and curing in step S5 as the initial state of the structural analysis, using finite element calculation software to determine the compressive stress increase influence matrix of the first bridge deck located in the second negative moment area when each inclined cable is tensioned;

[0020] S57, according to the compressive stress target value σ2 and the compressive stress increase influence matrix, the cable force increase value corresponding to each inclined cable is obtained, and then the design value is determined according to the cable force increase value.

[0021] Preferably, the step S1 specifically comprises the steps of:

[0022] S11, build the support for the continuous composite beam;

[0023] S12, first hoisting a first steel beam segment located at the top of the pier of the continuous composite beam on the bracket;

[0024] S13, continue to hoist the first steel beam segment of the pier on the side close to the cable-stayed bridge composite beam to the maximum cantilever state, and hoist the first steel beam segment of the pier on the side far from the cable-stayed bridge composite beam to the maximum cantilever state;

[0025] S14, after all the first steel beam segments are connected as a whole, the first bridge deck corresponding to each first steel beam segment is hoisted, and a first wet joint is reserved between two adjacent first bridge decks.

[0026] Preferably, the step S2 specifically comprises the steps of:

[0027] S21, using a bridge crane to hoist the kth second steel beam segment of the cable-stayed bridge composite beam, installing and initially tensioning the kth inclined cable, hoisting the kth second bridge deck, casting the kth second wet joint, tensioning the kth inclined cable, and moving the bridge crane forward to the kth second steel beam segment; wherein k is a positive integer, the initial value of k is 1, and the first second steel beam segment is adjacent to the joint section steel beam;

[0028] S22, determine whether the kth second steel beam segment is the second steel beam segment corresponding to the maximum cantilever state; if so, determine whether the second steel beam segment and the second bridge deck of the cable-stayed bridge composite beam are constructed to the maximum cantilever state; if not, assign k+1 to k and return to step S21.

[0029] Preferably, the step S14 of connecting all the first steel beam segments into a whole specifically includes: two adjacent first steel beam segments are connected into a whole by welding or bolts.

[0030] Preferably, the length of the steel beam of the joint section is set between 2-4m.

[0031] Preferably, the maximum cantilever length on one side of the continuous composite beam is within 200 m, and the maximum cantilever length of the composite beam of the cable-stayed bridge is within 200 m.

[0032] Preferably, the design conditions include one or more of design conditions that meet the anti-cracking requirements of the specifications under construction, design conditions that meet the anti-cracking requirements of the specifications under completed bridge status, and design conditions that meet the anti-cracking requirements of the specifications under operation status.

[0033] Preferably, the influence matrix is ​​related to factors such as structural stiffness and span arrangement, and is the influence of changes in the unit cable force of each cable on the compressive stress of the bridge deck at the pier top.

[0034] Preferably, the widths of the first wet seam, the second wet seam, the third wet seam and the fourth wet seam are set between 0.3-0.5m.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) By adopting this construction method, it is not necessary to install a large number of prestressed corrugated pipes and steel strands at the top of the continuous composite beam pier, which can save the time of construction processes such as installing corrugated pipes, inserting prestressed steel strands, tensioning prestressed steel strands, and grouting corrugated pipes. It can also save related material costs, equipment costs and personnel costs, thereby achieving the effect of shortening construction period and reducing construction costs.

[0037] (2) It avoids the need to install prestressed corrugated tubes in bridge decks and wet joints to weaken their cross-sectional area. At the same time, it avoids the existence of corrugated tubes affecting the pouring quality of concrete, ensures their cross-sectional characteristics and construction quality, and improves the overall stress performance and durability of bridge decks and wet joints.

[0038] (3) Taking advantage of the structural characteristics of the cable-stayed-continuous collaborative system composite beam bridge, firstly, by changing the overlapping order of the continuous composite beam bridge deck, it is ensured that the bridge deck in the negative bending moment area of ​​the continuous composite beam does not generate tensile stress, while the bridge deck in the positive bending moment area generates compressive stress reserve. Secondly, by increasing the tension of the tensioned cable, the main beam on the side of the continuous composite beam close to the cable-stayed bridge is displaced upward, and the main beam on the side span is displaced downward, so that the bridge deck generates compressive stress and the steel main beam generates tensile stress. The compressive properties of concrete materials and the tensile properties of steel are fully utilized, and the material utilization rate is improved. The pre-compressive stress of the bridge deck is completed by the internal force distribution of the composite beam itself. This construction method is simple and easy to operate, and the structural force is clear, which ensures the rationality and safety of the structural force.

[0039] (4) For cable-stayed-continuous collaborative system composite beam bridges with larger spans, the relative negative bending moment at the pier top is larger. The above method can be used to provide a part of the pre-compressive stress to the bridge deck at the pier top of the continuous beam, and then a part of the compressive stress can be provided by configuring an appropriate amount of prestressed steel strands. This can further improve the spanning capacity of the cable-stayed-continuous collaborative system composite beam and promote the development of cable-stayed-continuous collaborative system composite beam bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0041] Figure 1 It is a schematic diagram of a construction method flow in one embodiment of the present invention;

[0042] Figure 2 Schematic diagram of a process for obtaining the design value in step S5 in one embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the support construction of the continuous composite beam and the cantilever construction of the composite beam of the cable-stayed bridge in one embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the maximum cantilever state of a continuous composite beam and a cable-stayed composite beam in one embodiment of the present invention;

[0045] Figure 5It is a schematic diagram after casting all the first wet joints in the first positive moment zone in one embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram of a continuous composite beam after some supports are removed in one embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of the jointing of a continuous composite beam and a composite beam of a cable-stayed bridge in one embodiment of the present invention;

[0048] Figure 8 It is a schematic diagram of casting a wet joint excluding the second negative moment zone in one embodiment of the present invention;

[0049] Fig. 9 It is a schematic diagram of a first wet joint in a second negative moment zone of a cast continuous composite beam in one embodiment of the present invention;

[0050] Fig.10 It is a schematic diagram of increasing the cable force of a cable-stayed bridge in one embodiment of the present invention.

[0051] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments.

[0052] Description of Figure Numbers:

[0053] 10. Support; 21. First bridge deck; 22. First wet joint; 23. Bridge pier; 31. Second bridge deck; 32. Second wet joint; 41. Joint section steel beam; 42. Joint section bridge deck. DETAILED DESCRIPTION

[0054] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0057] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0058] Please refer to the attached Figures 1 to 10 In one embodiment of the present invention, a construction method of a cable-stayed-continuous cooperative system composite beam bridge comprises the following steps:

[0059] S1, constructing the first steel beam segment of the continuous composite beam on the support 10 step by step to the maximum cantilever state, hoisting the first bridge deck 21 and reserving the first wet joint 22 between two adjacent first bridge decks 21;

[0060] like Figure 3 As shown, the first steel beam segment of the continuous composite beam is firstly constructed on the bracket 10 in sections to the maximum cantilever state. In a preferred example, in order to facilitate those skilled in the art to fully understand the construction process of the present application, the present application is attached. Figures 3 to 10 The first steel beam segments are numbered in , where L is the starting first steel beam segment, located at the pier top position of the pier 23 of the continuous composite beam, and starting from the starting first steel beam segment to the right, there are the L+1th first steel beam segment to the L+ith first steel beam segment, and the L+ith first steel beam segment is the first steel beam segment corresponding to the maximum cantilever state on the right, and starting from the starting first steel beam segment to the left, there are the L-1th first steel beam segment to the Lith first steel beam segment, and the Lith first steel beam segment is the first steel beam segment corresponding to the maximum cantilever state on the left, and the first bridge deck 21 is hoisted on the top of each first steel beam segment.

[0061] As a preferred implementation, the step S1 specifically includes the following steps:

[0062] S11, build a support 10 for the continuous composite beam; S12, first hoist the first steel beam segment located at the top of the pier 23 of the continuous composite beam on the support 10; S13, continue to hoist the first steel beam segment of the pier 23 on the side close to the cable-stayed bridge composite beam to the maximum cantilever state section by section, and hoist the first steel beam segment of the pier 23 on the side away from the cable-stayed bridge composite beam to the maximum cantilever state section by section; S14, after connecting all the first steel beam segments as a whole, hoist the first bridge deck 21 corresponding to each first steel beam segment, and reserve a first wet joint 22 between two adjacent first bridge decks 21.

[0063] Specifically, by building a bracket 10 as a supporting platform, the construction process of the entire continuous composite beam is made more stable and safe. The bracket 10 can bear the weight of the first steel beam segment and the first bridge deck 21 to prevent collapse or deformation during the construction process, thereby ensuring the safety of construction workers; the use of a segment-by-segment lifting method can make the construction process more orderly and efficient, improve construction efficiency, and shorten the construction period.

[0064] Furthermore, the step S14 of connecting all the first steel beam segments as a whole specifically includes: two adjacent first steel beam segments are connected as a whole by welding or bolting. Specifically, welding or bolting can ensure a tight connection between two adjacent first steel beam segments, so that the entire continuous composite beam is more structurally stable. This stable connection method can resist external loads and internal stresses, and ensure the safety and durability of the bridge.

[0065] S2, cantilever construction of the second steel beam segment and the second bridge deck 31 of the cable-stayed bridge composite beam to the maximum cantilever state, and reserve a second wet joint 32 between two adjacent second bridge decks 31;

[0066] like Figure 4 As shown in the preferred example, in order to facilitate those skilled in the art to fully understand the construction process of this application, the application is attached Figures 3 to 10 The first steel beam segments are numbered in the figure, the Nth second steel beam segment is the first second steel beam segment of the cable-stayed bridge composite beam, and the cantilever construction is adopted to gradually construct from the Nth second steel beam segment to the Nith second steel beam segment, and the Nith second steel beam segment is the second steel beam segment corresponding to the maximum cantilever state. A second bridge deck 31 is installed on the top of each second steel beam segment, and each second bridge deck 31 is connected to a pair of inclined cables (symmetrically arranged on both sides of the second bridge deck 31). For the sake of simplicity, this embodiment In this example, only the inclined cables on one side of the bridge deck are numbered for illustration, for instance, the single-sided inclined cable corresponding to the N-th second steel beam segment is numbered as the n-th inclined cable, and the cable force design value corresponding to the n-th inclined cable is Fn, where Fn is the cable force value without considering the compensation for the compressive stress of the bridge deck. Similarly, the single-sided inclined cable corresponding to the Ni-th second steel beam segment is numbered as the ni-th inclined cable, and the cable force design value of the ni-th inclined cable is Fn-i, where Fn-i is the cable force value without considering the compensation for the compressive stress of the bridge deck.

[0067] As a preferred implementation, the step S2 specifically includes the following steps:

[0068] S21, use a bridge crane to hoist the kth second steel beam segment of the cable-stayed bridge composite beam, install and initially tension the kth inclined cable, hoist the kth second bridge deck 31, cast the kth second wet joint 32, and tension the kth inclined cable. The bridge crane moves forward to the kth second steel beam segment; wherein k is a positive integer, the starting value of k is 1, and the first second steel beam segment is adjacent to the joint section steel beam 41; it should be noted that, in combination with the above numbering, when k is 1, the Nth second steel beam segment of the cable-stayed bridge composite beam is hoisted, and the nth inclined cable is installed and initially tensioned.

[0069] S22, determine whether the kth second steel beam segment is the second steel beam segment corresponding to the maximum cantilever state; if so, determine whether the second steel beam segment and the second bridge deck 31 of the cable-stayed bridge composite beam are constructed to the maximum cantilever state; if not, assign k+1 to k and return to step S21.

[0070] Specifically, this embodiment realizes the rapid installation of the second steel beam segment, the inclined cable and the second bridge deck 31 by using a bridge crane for hoisting operations. At the same time, the steps of hoisting, installation, initial extension of the inclined cable, casting of the second wet joint 32 and the second extension of the inclined cable are executed cyclically, making the construction process more orderly and efficient, and significantly improving the construction efficiency. During the hoisting process, the steel beam segment is initially stabilized by the initial extension of the inclined cable to prevent it from excessive deformation or instability during the hoisting process; after the hoisting of each second steel beam segment is completed, the corresponding second wet joint 32 is cast to timely overlap the second bridge deck 31 and the second steel beam segment. At the same time, the stress state of the steel beam segment is further adjusted by the two inclined cables to make it more in line with the design requirements, thereby ensuring the construction quality.

[0071] By adopting the present application scheme, it is not necessary to set up a large number of prestressed corrugated pipes and steel bundles at the top of the continuous composite beam pier, which can save the time of construction processes such as installing corrugated pipes, inserting prestressed steel bundles, tensioning prestressed steel bundles, and grouting corrugated pipes, and can also save related material costs, equipment costs and personnel costs, thereby achieving the effect of saving construction period and reducing construction costs; it avoids the weakening of the cross-sectional area by setting prestressed corrugated pipes in the bridge deck and wet joints, and at the same time avoids the existence of the corrugated pipes affecting the pouring quality of concrete, ensures its cross-sectional characteristics and construction quality, and improves the overall stress performance and durability of the bridge deck and wet joints.

[0072] S3, cast all the first wet joints 22 located in the first positive bending moment zone, and do not cast the first wet joints 22 located in the first negative bending moment zone for the time being, and remove the bracket 10 to allow the first steel beam segment to move downward; wherein, the continuous composite beam includes a first negative bending moment zone and a first positive bending moment zone away from the cable-stayed bridge composite beam after being removed from the bracket; specifically, remove the bracket 10 of the continuous composite beam to allow the first steel beam segment to move downward, so that the first bridge deck 21 in the first positive bending moment zone has a certain compressive stress reserve, while ensuring that the first bridge deck 21 in the first negative bending moment zone does not generate tensile stress.

[0073] S4, hoist the steel beam 41 of the joint section to complete the connection and jointing of the continuous composite beam and the composite beam of the cable-stayed bridge, hoist the bridge deck 42 of the joint section, and reserve a third wet joint between the bridge deck 42 of the joint section and the first bridge deck 21, and reserve a fourth wet joint between the bridge deck 42 of the joint section and the second bridge deck 31, and then cast the third wet joint, the fourth wet joint and all the first wet joints 22 in the second positive bending moment zone in this structural state, and the first wet joints 22 located in the second negative bending moment zone are not cast for the time being; specifically, cast all the first wet joints 22 in the second positive bending moment zone in this structural state, the third wet joints, the fourth wet joints, and the curing wet joints to complete the overlap of the bridge deck and the steel beam corresponding to the concrete, and the first wet joints 22 in the second negative bending moment zone are not cast for the time being, and at this time, the first bridge deck 21 in the second negative bending moment zone of the continuous beam pier top does not generate tensile stress.

[0074] Furthermore, the widths of the first wet seam 22, the second wet seam 32, the third wet seam, and the fourth wet seam are set between 0.3-0.5 m.

[0075] S5, casting the first wet joint 22 located in the second negative bending moment zone, and starting from the side close to the second positive bending moment zone, sequentially tensioning multiple inclined cables to the design value, so that after tensioning, the pier 23 located in the continuous composite beam is displaced upward on the first steel beam segment close to the joint section steel beam 41, and the pier 23 located in the continuous composite beam is displaced downward on the first steel beam segment away from the joint section steel beam 41.

[0076] Specifically, the first wet joint 22 of the second negative bending moment zone of the continuous beam pier is finally cast, and the wet joint is cured to complete the overlap of the corresponding bridge deck and the steel beam. At this time, the first bridge deck 21 of the second negative bending moment zone of the continuous beam pier top is still in a state of no tensile stress; the nth to nith inclined cables are tensioned in sequence, and after tensioning, the L+1th to L+ith first steel beam segments of the continuous composite beam are displaced upward, and the L-1th to Lith first steel beam segments are displaced downward, so that the first bridge deck 21 of the continuous composite beam generates compressive stress, and the first bridge deck 21 has a compressive stress reserve.

[0077] The present application scheme utilizes the structural characteristics of the cable-stayed-continuous collaborative system composite beam bridge. Firstly, by changing the overlapping sequence of the continuous composite beam bridge deck, it is ensured that the bridge deck in the negative bending moment area of ​​the continuous composite beam does not generate tensile stress, while the bridge deck in the positive bending moment area generates compressive stress reserve. Secondly, by increasing the tension of the tensioned cable, the continuous composite beam is displaced upward on the main beam close to the cable-stayed bridge side, and the main beam on the side span is displaced downward, so that the bridge deck generates compressive stress and the steel main beam generates tensile stress, giving full play to the compressive properties of concrete materials and the tensile properties of steel materials, improving the material utilization rate, and the pre-compressive stress of the bridge deck is completed by the internal force distribution of the composite beam itself. The construction method is simple and operable, and the structural force is clear, which ensures the rationality and safety of the structural force.

[0078] As a preferred implementation, the design value in step S5 is obtained by the following steps:

[0079] S51, when the first bridge deck 21 does not consider the prestressing construction measures, the tensile stress distribution of the first bridge deck 21, and determine the size and range of the prestressing stress required to be applied to the first bridge deck 21 when meeting the anti-cracking requirements of the specification according to the tensile stress distribution;

[0080] Specifically, the present embodiment can use finite element calculation software to simulate the construction process and construction load of the structure, obtain the tensile stress distribution of the first bridge deck 21 during the construction process, and consider the influence of vehicle moving load, temperature load, wind load, support settlement and other loads during the later operation process, and obtain the tensile stress distribution of the first bridge deck 21 during the operation process. The sum of the two is the overall tensile stress distribution of the first bridge deck 21. To prevent the bridge deck concrete from cracking, the compressive stress applied to the first bridge deck 21 should be greater than the sum of the above two.

[0081] S52, obtaining the maximum tensile stress of the first bridge deck 21 according to the tensile stress distribution, and taking the cross section corresponding to the maximum tensile stress as the target control cross section;

[0082] S53, obtaining the compressive stress reserve required for the target control section to meet the design conditions, and taking the difference between the maximum tensile stress corresponding to the target control section and the compressive stress reserve as the compressive stress target value σ to be applied to the first bridge deck 21 总 ;

[0083] Furthermore, the design conditions include one or more of design conditions that meet the anti-cracking requirements of the specifications under construction, design conditions that meet the anti-cracking requirements of the specifications under completed bridge status, and design conditions that meet the anti-cracking requirements of the specifications under operation status.

[0084] S54, obtaining a tensile stress reduction value σ1 of the first bridge deck 21 located in the second negative bending moment area after the first wet joint 22 located in the second negative bending moment area is cast and cured in step S5;

[0085] S55, determining the compressive stress target value σ 总 The difference between the tensile stress reduction value σ1 and the compressive stress target value σ2 required for cable tensioning is obtained;

[0086] S56, taking the first wet joint 22 located in the second negative moment area after casting and curing in step S5 as the initial state of the structural analysis, using finite element calculation software to determine the compressive stress increase influence matrix of the first bridge deck 21 located in the second negative moment area when each inclined cable is tensioned;

[0087] S57, according to the compressive stress target value σ2 and the compressive stress increase influence matrix, the cable force increase value corresponding to each inclined cable is obtained, and then the design value is determined according to the cable force increase value.

[0088] Specifically, by analyzing the overall stress of the cable-stayed bridge composite beam during the cantilever construction stage, the cable force values ​​ΔFn~ΔFn-i required to adjust the cables n~ni are reserved while ensuring that the second steel beam segment, the second bridge deck 31, the main tower and the cable forces of the cable-stayed bridge composite beam meet the regulatory requirements during the cantilever construction stage. At the same time, it is necessary to ensure that the relevant stress of the entire structure during the bridge operation stage meets the relevant regulatory requirements. This embodiment ensures the scientificity and effectiveness of the application of prestress and the tensioning process through precise calculation and analysis, which not only helps to improve the crack resistance of the bridge deck, but also reduces rework and maintenance work caused by improper construction, thereby improving construction quality and efficiency.

[0089] Determining the design value according to the cable force increase value can specifically be to adjust the cable force from large to small according to the influence of the cable force of different numbers on the pre-compressive stress of the bridge deck at the pier top, and first increase the N with the largest influence according to the compressive stress increase influence matrix. max #The cable force of the cable stay reaches the target compressive stress value. Finite element software such as Mkdas / ckvkl is used to analyze whether the uniformity of the overall cable force of the cable-stayed bridge and the structural stress meet the requirements of the specification under this cable force condition. If the above conditions are not met, then adjust N according to the compressive stress increase influence matrix. max # and N max-1 # The cable is adjusted to the target compressive stress value, and the above steps are repeated until the adjusted N is determined. max #~N max-n #The range and cable tension of the cable-stayed cables reach the target compressive stress value σ2. At the same time, the overall cable tension of the cable-stayed bridge is uniform and the structural stress meets the requirements.

[0090] As a preferred example, the length of the joint section steel beam 41 is set between 2-4 m.

[0091] As a preferred example, the maximum cantilever length on one side of the continuous composite beam is within 200 m, and the maximum cantilever length of the composite beam of the cable-stayed bridge is within 200 m.

[0092] Furthermore, the steel beams in the composite beam include main longitudinal beams, transverse beams, and small longitudinal beams. The steel beams form a lattice structure. Several bridge decks are laid on the steel beam lattice structure. Shear nails are welded on the top plates of the steel beams at the wet joint concrete positions between the bridge decks to ensure that the bridge decks participate in the coordinated force of the steel beams.

[0093] Furthermore, the construction of wet joints includes the installation and welding of steel bars between bridge decks, the pouring of wet joint concrete after the bridge decks are moistened, and the curing of wet joints. The curing time is generally required to be no less than 5 days. After the curing requirements are met, the bridge deck and the steel beam are overlapped to form a whole to participate in the load.

[0094] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the protection scope of the present invention.

Claims

1. A construction method for a cable-stayed-continuous cooperative system composite beam bridge, characterized in that: The following steps are involved: S1, constructing the first steel beam segment of the continuous composite beam on the support step by step to the maximum cantilever state, hoisting the first bridge deck and reserving the first wet joint between two adjacent first bridge decks; S2, cantilever construction of the second steel beam segment and the second bridge deck of the cable-stayed bridge composite beam to the maximum cantilever state, and reserve a second wet joint between two adjacent second bridge decks; S3, casting all the first wet joints located in the first positive bending moment zone, not casting the first wet joints located in the first negative bending moment zone for the time being, and removing the support to allow the first steel beam segment to move downward; wherein the continuous composite beam includes the first negative bending moment zone and the first positive bending moment zone away from the composite beam of the cable-stayed bridge after the support is removed; S4, hoisting the steel beam of the joint section, completing the joint connection between the continuous composite beam and the composite beam of the cable-stayed bridge, hoisting the bridge deck of the joint section, and reserving a third wet joint between the bridge deck of the joint section and the first bridge deck, and reserving a fourth wet joint between the bridge deck of the joint section and the second bridge deck, and then casting the third wet joint, the fourth wet joint and all the first wet joints in the second positive bending moment zone in this structural state, and the first wet joint located in the second negative bending moment zone is not cast temporarily; wherein, after the joint connection between the continuous composite beam and the composite beam of the cable-stayed bridge includes the second negative bending moment zone and the second positive bending moment zone close to the composite beam of the cable-stayed bridge; S5, casting the first wet joint located in the second negative bending moment zone, and starting from the side close to the second positive bending moment zone, sequentially tensioning multiple inclined cables to the design value, so that after tensioning, the bridge pier located at the first steel beam segment close to the joint section steel beam side of the continuous composite beam is displaced upward, and the bridge pier located at the first steel beam segment away from the joint section steel beam side of the continuous composite beam is displaced downward.

2. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 1 is characterized in that: The design value in step S5 is obtained by the following steps: S51, when the first bridge deck does not consider the prestressing construction measures, the tensile stress distribution of the first bridge deck, and determine the size and range of the prestressing stress required to be applied to the first bridge deck when meeting the anti-cracking requirements of the specification according to the tensile stress distribution; S52, obtaining the maximum tensile stress of the first bridge deck according to the tensile stress distribution, and taking the cross section corresponding to the maximum tensile stress as the target control cross section; S53, obtaining the compressive stress reserve required for the target control section to meet the design conditions, and taking the difference between the maximum tensile stress corresponding to the target control section and the compressive stress reserve as the compressive stress target value σ to be applied to the first bridge deck 总 ; S54, obtaining a tensile stress reduction value σ1 of the first bridge deck located in the second negative bending moment area after the first wet joint located in the second negative bending moment area is cast and cured in step S5; S55, determining the compressive stress target value σ 总 The difference between the tensile stress reduction value σ1 and the compressive stress target value σ2 required for cable tensioning is obtained; S56, taking the first wet joint located in the second negative moment area after casting and curing in step S5 as the initial state of the structural analysis, using finite element calculation software to determine the compressive stress increase influence matrix of the first bridge deck located in the second negative moment area when each inclined cable is tensioned; S57, according to the compressive stress target value σ2 and the compressive stress increase influence matrix, the cable force increase value corresponding to each inclined cable is obtained, and then the design value is determined according to the cable force increase value.

3. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 1, characterized in that: The step S1 specifically includes the following steps: S11, build the support for the continuous composite beam; S12, first hoisting a first steel beam segment located at the top of the pier of the continuous composite beam on the bracket; S13, continue to hoist the first steel beam segment of the pier on the side close to the cable-stayed bridge composite beam to the maximum cantilever state, and hoist the first steel beam segment of the pier on the side far from the cable-stayed bridge composite beam to the maximum cantilever state; S14, after all the first steel beam segments are connected as a whole, the first bridge deck corresponding to each first steel beam segment is hoisted, and a first wet joint is reserved between two adjacent first bridge decks.

4. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 1, characterized in that: The step S2 specifically includes the following steps: S21, using a bridge crane to hoist the kth second steel beam segment of the cable-stayed bridge composite beam, installing and initially tensioning the kth inclined cable, hoisting the kth second bridge deck, casting the kth second wet joint, tensioning the kth inclined cable, and moving the bridge crane forward to the kth second steel beam segment; wherein k is a positive integer, the initial value of k is 1, and the first second steel beam segment is adjacent to the joint section steel beam; S22, determine whether the kth second steel beam segment is the second steel beam segment corresponding to the maximum cantilever state; if so, determine whether the second steel beam segment and the second bridge deck of the cable-stayed bridge composite beam are constructed to the maximum cantilever state; if not, assign k+1 to k and return to step S21.

5. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 3, characterized in that: The step S14 of connecting all the first steel beam segments into a whole specifically includes: two adjacent first steel beam segments are connected into a whole by welding or bolts.

6. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 1, characterized in that: The length of the joint section steel beam is set between 2-4m.

7. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 1, characterized in that: The maximum cantilever length on one side of the continuous composite beam is within 200m, and the maximum cantilever length of the cable-stayed bridge composite beam is within 200m.

8. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 2, characterized in that: The design conditions include one or more of the following: design conditions that meet the anti-cracking requirements of the specifications under construction, design conditions that meet the anti-cracking requirements of the specifications under completed bridge status, and design conditions that meet the anti-cracking requirements of the specifications under operation status.

9. The construction method of the cable-stayed-continuous coordinated system composite beam bridge according to claim 2, characterized in that: The widths of the first wet seam, the second wet seam, the third wet seam and the fourth wet seam are set between 0.3-0.5m.

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