Bridge seismic resistance method and structure with multi-stage ordered reset energy dissipation

Abstract

The present application relates to the technical field of bridge, in particular to a bridge anti-seismic method and structure with multi-stage ordered reset energy dissipation, which can activate each stage of anti-seismic mechanism according to the expected design order under a once-in-a-lifetime earthquake, and can ensure that the bridge adapts to different earthquakes with different performance states, has flexible isolation and self-resetting function under small earthquakes, can pass through directly without repair after the earthquake; has the function of sliding isolation and energy dissipation under medium earthquakes, the main components are not damaged after the earthquake, and only the T-beam reset and the quick replacement of the mild steel energy dissipation element are needed to restore the traffic; has the function of automatic anti-falling beam under a large earthquake, and changes the force transmission path of the bridge structure; under a once-in-a-lifetime earthquake, the bridge is converted from the isolation mode to the ductility mode, the plastic hinge of the pier column is used for hysteresis energy dissipation to resist the earthquake, the seismic potential of the bridge structure is excavated to the greatest extent, and the life safety is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridges, in particular to a bridge anti-seismic method and structure with multi-stage ordered reset energy dissipation. BACKGROUND

[0002] In small and medium span bridges, prestressed reinforced concrete T-beams are one of the most widely used bridge span structure forms, the supports of which usually adopt plate rubber bearings with simple structure, convenient construction and low cost, and the substructures of which usually adopt reinforced concrete double-column piers and gravity abutments. At present, the traditional design structure of this kind of bridge is to directly place the T-beam on the plate rubber bearing, and the plate rubber bearing is directly placed on the bridge substructure, and there is lack of fixing measures between the three, which belongs to a typical weak connection structure. Although this structure can reduce the seismic response of the bridge substructure through flexible support, it will also cause the T-beam to have too large seismic displacement and even lose control, and cause a series of seismic damages such as shear, edge rolling, emptying, throwing out of the plate rubber bearing, and shear of the limiting block and collision of the adjacent bridge span structure, and even cause extreme beam falling seismic damage. SUMMARY

[0003] The purpose of the present application is to provide a bridge anti-seismic method and structure with multi-stage ordered reset energy dissipation to solve the problem that the seismic resistance of each component of the bridge cannot be effectively mobilized in the prior art.

[0004] The embodiments of the present application are implemented by the following technical solutions:

[0005] A bridge anti-seismic method with multi-stage ordered reset energy dissipation, comprising:

[0006] A first-stage constraint system, the first-stage constraint system comprising a rubber bearing and a reset component, the rubber bearing being used to connect between a support structure and a T-beam, and the reset component being used to connect with the T-beam to dissipate seismic energy, the first-stage constraint system starting to work when ground vibration starts;

[0007] A second-stage constraint system, the second-stage constraint system comprising an energy dissipation element, the energy dissipation element being used to connect with the T-beam to dissipate seismic energy, the second-stage constraint system starting to work when ground vibration is enhanced;

[0008] A third-stage constraint system, the third-stage constraint system comprising a locking block and a locking groove, the locking block being arranged on the support structure and connected to the bottom of the rubber bearing, the gap between adjacent locking blocks forming the locking groove, the third-stage constraint system starting to work when ground vibration is further enhanced;

[0009] The fourth level constraint system comprises a pier which is connected with the support structure by a plastic hinge, and the fourth level constraint system starts to work when the ground vibration continues to increase;

[0010] The first level constraint system, the second level constraint system, the third level constraint system and the fourth level constraint system start to work in turn according to the ground vibration intensity.

[0011] The bridge anti-seismic structure with multi-level ordered reset energy dissipation comprises a bridge anti-seismic method as described above, and is characterized in that the working condition of the first level constraint system is that:

[0012] Delta Delta 0

[0013] In the above formula, Delta is the displacement of the T-beam, and Delta 0 is the elastic limit deformation of the rubber support.

[0014] In an embodiment of the present application, the bottom of the rubber support is provided with a first steel plate and is connected to the locking block by a first bolt, and the shear strength of the first bolt is:

[0015] Q b Greater than or equal to 2F f / (N b ·n b )

[0016] In the above formula, Q b is the shear strength of the first bolt, F f is the sum of the static friction of all rubber supports, N b is the number of rubber supports on each pier, and n b is the number of first bolts used by a single rubber support.

[0017] In an embodiment of the present application, the working condition of the second level constraint system is that:

[0018] Delta 0 is less than or equal to Delta and Delta 0 plus Delta Eu

[0019] In the above formula, Delta Eu is the limit deformation of the energy dissipation element.

[0020] In an embodiment of the present application, the energy dissipation element comprises a plurality of second steel plates with through holes in the middle, the upper end of the second steel plate is connected with the reset assembly by a second bolt, the lower end of the second steel plate is connected with a connecting groove by a second bolt, and the connecting groove is connected with the support structure by a third bolt, and the shear strength of the second bolt is:

[0021]

[0022] The shear strength of the third bolt is:

[0023]

[0024] The design ultimate strength of the energy dissipation element is:

[0025]

[0026] The design ultimate strength of the second steel plate is:

[0027] Δ Eu = 0.2h

[0028] In the above formula, is the ultimate strength of the second steel plate, N E is the number of the second steel plates in one energy dissipation element, n r1 is the number of high-strength bolts used for one piece of the perforated soft steel plate, n r2 is the number of anchoring bolts used for one soft steel energy dissipation element, h is the height of the perforated soft steel plate, σ u is the ultimate stress of the perforated soft steel plate, b and t are the width and thickness of the perforated soft steel plate, and θ is the ultimate deformation angle.

[0029] In an embodiment of the present application, the reset assembly comprises a reset spring, a bidirectional sliding groove and a screw rod, the bidirectional sliding groove is connected to the top of the second steel plate, the screw rod is slidingly connected in the bidirectional sliding groove, the reset spring is sleeved on the screw rod, the two ends of the screw rod are respectively connected with a snap ring and a nut for limiting, one end of the reset spring is connected with the bidirectional sliding groove, and the other end is connected with the T-beam.

[0030] In an embodiment of the present application, the distance between the snap ring and the nut is:

[0031] L c = W E + 2Δ0

[0032] The width and height of the through hole on the bidirectional sliding groove for the screw rod sliding are respectively:

[0033] w Ec = d g + Δ ej h Ec = d g + 5mm

[0034] The inner diameter, the ultimate compression amount and the stiffness of the reset spring are:

[0035] d t ≥ h Ec + 50mm

[0036] Δt = H b

[0037] k t <0.2N E K ES / N g

[0038] wherein W E is the length of the bidirectional sliding groove, Δ0 is the elastic limit deformation of the rubber support, d g is the diameter of the screw rod, Δ ej is the expansion amount of the support structure corresponding to or adjacent to the expansion joint, d t is the inner diameter of the reset spring, Δ t is the limit compression amount of the reset spring, k t is the stiffness of the reset spring, h Ec is the notch height of the bidirectional sliding groove, H b is the height of the rubber support, K ES is the initial elastic stiffness of the second steel plate, N g is the number of screw rods, N g ≥ 3.

[0039] In an embodiment of the present application, a reinforcing mesh and vertically arranged shear reinforcement are arranged around the locking block, the shear reinforcement is arranged in the support structure, the length of the shear reinforcement is greater than ten times the diameter of the shear reinforcement, and the condition for the third level of constraint system to start working is:

[0040] Δ ≥ Δ0 + Δ Eu

[0041] The height of the locking block is:

[0042] H k = H mt - H b

[0043] The laying area of the shear reinforcement is:

[0044] A sv ≥ 1.2V sub / (f dv · N k )

[0045] wherein H mt is the height of the T-beam (1) lower horseshoe, H b is the height of the rubber support, V sub is the shear strength of the support structure, f dv is the tensile strength design value of the shear reinforcement, N k is the number of locking blocks.

[0046] In an embodiment of the present application, the width of the locking groove is:

[0047] W c = W mt + 50mm

[0048] In the formula, W mt is the width of the horseshoe under the T-beam.

[0049] The technical solution of the embodiment of the present application has at least the following advantages and beneficial effects:

[0050] 1. The present application can activate each level of seismic mechanism in the expected design order under a rarely occurring earthquake, and can also ensure that the bridge adapts to different sizes of earthquakes in different performance states, has flexible seismic isolation and self-resetting function under smaller earthquakes, and can pass directly after the earthquake without repair; has the functions of sliding isolation and energy dissipation under moderate earthquakes, and the main components are not damaged after the earthquake, and only the T-beam needs to be reset and the mild steel energy dissipation element needs to be replaced quickly to restore traffic; has the function of automatic anti-falling beam under a large earthquake, and changes the force transmission path of the bridge structure; under a rarely occurring earthquake, the bridge is converted from the isolation mode to the ductility mode, and the plastic hinge of the pier column resists the earthquake through hysteresis energy dissipation, thereby maximizing the seismic potential of the bridge structure and ensuring life safety.

[0051] 2. In addition, the greatest advantage of the present application is that the traditional structure form of the small and medium span T-beam bridge is not changed greatly, which is easy for designers to accept and understand, the main anti-seismic structure and constraint system are simple in structure, low in cost, convenient in construction, and can be quickly replaced after the earthquake, and have a significant advantage in the large number of T-beam bridges, and have a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0053] Figure 1 is a schematic diagram of the overall structure of the present application;

[0054] Figure 2 is a schematic diagram of the present application when the rubber support starts to produce elastic shear deformation;

[0055] Figure 3 is a schematic diagram of the present application when the energy dissipation element enters the plastic energy dissipation state;

[0056] Figure 4 is a schematic diagram of the present application when the T-beam falls into the locking groove;

[0057] Figure 5 The structural schematic diagram of the energy dissipation element and the reset component of the present application;

[0058] Figure 6 The front view of the present application Figure 5 ;

[0059] Figure 7 The structural schematic diagram of the rubber support of the present application

[0060] Figure 8 The structural schematic diagram of the steel bar net of the present application

[0061] Figure: 1-reset component, 101-screw rod, 102-reset spring, 103-clasp, 104-bidirectional sliding groove, 105-nut, 2-T beam, 3-supporting structure, 4-locking groove, 5-rubber support, 6-locking block, 7-energy dissipation element, 701-second steel plate, 702-connecting groove, 703-second bolt, 704-third bolt, 8-first steel plate, 9-first bolt, 10-shear steel bar, 11-steel bar net. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to 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. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0063] Please refer to 1-8, the present application provides a kind of multistage ordered reset energy dissipation bridge seismic method, main including first level restraint system, second level restraint system, third level restraint system and fourth level restraint system, first level restraint system, second level restraint system, third level restraint system and fourth level restraint system work in turn according to ground vibration intensity.

[0064] Among them, first level restraint system mainly includes rubber support 5 and reset component 1, rubber support 5 is connected between supporting structure 3 and T beam 2, specifically located in the upper portion of supporting structure 3, the bottom of T beam 2, reset component 1 is provided with two groups of T beam 2 respectively connected to two sides, the other end of reset component 1 is connected to second level restraint system, for consuming the energy of vibration, T beam 2 is traditional prefabricated prestressed concrete T beam 2, and steel plate must be embedded in the lower horseshoe bottom surface.

[0065] The rubber support 5 is mainly an anchor bolted plate type rubber support 5, which is different from the traditional plate type rubber support 5. The traditional plate type rubber support 5 lacks a leakage hole of a constraint mechanism. The rubber support 5 in the application is provided with a first steel plate 8 with bolt holes at the bottom of the rubber support 5 and is connected to the locking block 6 of the third constraint system through the first bolt 9. The thickness of the first steel plate 8 is not less than 20 mm, and the peripheral size is greater than 100 mm. The first steel plate 8 is integrally bonded with the bottom surface of the rubber support 5, and the bolt holes are uniformly arranged on the periphery of the first steel plate 8. The rubber support 5 and the locking block 6 are fixed together through the first bolt 9. In order to ensure the fixed state, the shear strength Qb of a single bolt should satisfy:

[0066] Q b ≥2F f / (N b ·n b )

[0067] F f is the sum of the static friction of all rubber supports 5, N b is the number of supports on each pier, and n b is the number of first bolts 9 used for a single rubber support 5.

[0068] The reset assembly 1 mainly includes a reset spring 102, a bidirectional sliding groove 104 and a screw rod 101. The bidirectional sliding groove 104 is connected to the top of the second steel plate 701, the screw rod 101 is slidingly connected in the bidirectional sliding groove 104, the reset spring 102 is sleeved on the screw rod 101, the two ends of the screw rod 101 are respectively connected with a clasp ring 103 and a nut 105 for limiting, and one end of the reset spring 102 is connected with the bidirectional sliding groove 104 and the other end is connected with the T beam 2.

[0069] The bidirectional sliding groove 104 is mainly composed of upper and lower cover plates and inner and outer side plates, which are all made of steel plates with a thickness not less than 20 mm. The inner and outer side plates are provided with oval sliding slots aligned inside and outside. In order to ensure the installation of the long screw rod 101 and ensure that the long screw rod 101 can freely slide in the longitudinal direction of the slot, so as to meet the temperature expansion requirement of the T beam 2, the width w Ec and the height h Ec of the oval sliding slot should satisfy:

[0070] w Ec =d g +Δ ej h Ec =d g +5mm

[0071] d g is the diameter of the long screw rod 101, and Δ e is the expansion amount of the corresponding or adjacent expansion joint of the support structure 3.

[0072] In order to ensure that the screw rod 101 has sufficient strength and stiffness to ensure that it can freely slide in the longitudinal direction and the transverse direction within the oval slot of the bidirectional sliding groove 104, the diameter of the screw rod 101 should not be less than 30 mm. The long screw rod 101 is a key component connecting the energy dissipation element 7 and the T-beam 2, and is also a trigger determining the starting time of the energy dissipation element 7. Before the deformation of the T-beam 2 is less than the elastic limit deformation of the plate rubber bearing 5, the flexibility of the plate rubber bearing 5 has a good isolation effect on the superstructure, and the displacement of the T-beam 2 is small, the overall force transmission path of the bridge structure is clear and reasonable, so the energy dissipation element 7 does not need to be started, only the additional restoring force of the reset spring 102 is needed to assist the flexibility recovery of the plate rubber bearing 5. In order to achieve the above goal, the snap ring 103 and the nut 105 are arranged outside the outer side of the long screw rod 101 located in the bidirectional sliding groove 104, the diameters of the snap ring 103 and the nut 105 should not be less than h Ec +30 mm, the widths of the snap ring 103 and the nut 105 should not be less than 50 mm, and the net distance Lc between the snap ring 103 and the nut 105 should satisfy:

[0073] L c =W E +2Δ0

[0074] In the formula, W E is the outer edge distance of the inner and outer side plates of the bidirectional sliding groove 104, and Δ0 is the elastic limit deformation of the rubber bearing 5. The above formula is to ensure that the energy dissipation element 7 starts to have energy dissipation effect when the displacement of the T-beam 2 reaches a certain threshold.

[0075] Further, in order to enhance the reset ability of the T-beam 2, the reset spring 102 is arranged on the screw rod 101, one end of the reset spring 102 is fixed with the T-beam 2, and the other end is fixed with the inner side plate of the bidirectional sliding groove 104, and is in a balanced position in the installed state. In order to prevent the reset spring 102 from starting the energy dissipation element 7 in advance, and in order to avoid that the reset spring 102 cannot start the mild steel energy dissipation element 7 in time due to its excessive compression amount, the limit compression amount Δ t and the stiffness k t of the reset spring 102 should satisfy:

[0076] Δ t =H b

[0077] k t <0.2N E K ES / N g

[0078] In the formula, H b is the height of the rubber bearing 5, and K ESN is the initial elastic stiffness of the second steel plate 701 g N is the number of the screw rod 101 g ≥ 3. In addition, in order to facilitate the installation of the return spring 102 on the screw rod 101, the inner diameter d t of the return spring 102 satisfies:

[0079] d t ≥ h Ec + 50 mm

[0080] In the formula, h Ec is the notch height of the bidirectional sliding groove 104.

[0081] The second-stage constraint system mainly includes the energy dissipation element 7, which includes a plurality of second steel plates 701 with through holes in the middle. The second steel plate 701 has strong plastic deformation capacity and energy dissipation capacity. The upper and lower ends of the second steel plate 701 are provided with standard bolt connection holes, which are convenient for installation, disassembly and replacement. The upper end of the second steel plate 701 is connected with the bidirectional sliding groove 104 of the reset assembly 1 through the second bolt 703, and the lower end is connected with the connecting groove 702 through the second bolt 703. The connecting groove 702 is connected with the locking block 6 on the supporting member through the third bolt 704.

[0082] In order to ensure that the second constraint system only occurs plastic deformation of the second steel plate 701 to dissipate energy under the action of lateral displacement, and the rest of the connection parts do not appear slip or shear failure phenomenon;

[0083] The shear strength of the second bolt 703 is:

[0084]

[0085] The shear strength of the third bolt 704 is:

[0086]

[0087] The design ultimate strength of the energy dissipation element 7 is:

[0088]

[0089] The design ultimate strength of the second steel plate 701 is:

[0090] Δ Eu = 0.2h

[0091] In the above formula, is the ultimate strength of the second steel plate 701, N E n is the number of the second steel plate 701 in one energy dissipation element 7, n r1 n is the number of high-strength bolts used for a single porous soft steel plate, n r2The number of anchor bolts used for a soft steel energy dissipation element 7, h is the height of the perforated soft steel plate, σ u The ultimate stress of the perforated soft steel plate, b, t are the width and thickness of the perforated soft steel plate, and θ is the ultimate deformation angle.

[0092] The third level constraint system includes locking blocks 6, which are made of reinforced concrete and are arranged on the support structure 3. The gap between two adjacent locking blocks 6 forms a locking groove 4. The locking blocks 6 serve to form the locking groove 4 and ensure that the seismic inertia force of the T-beam 2 can be transmitted to the support structure 3 in time after locking. In addition, the locking blocks 6 are also used for the rubber bearing 5 and the energy dissipation element 7. Therefore, the locking blocks 6 must meet the requirements of geometric size and mechanical strength. The height Hk of the locking block 6 should satisfy:

[0093] H k = H mt - H b

[0094] In the formula, H mt is the height of the horse's hoof under the T-beam 2, and H b is the height of the plate rubber bearing 5 with anchor bolts. In order to ensure the locking function of the locking block 6 and transmit the seismic inertia force of the T-beam 2, the locking block 6 is provided with vertical shear reinforcement 10 and construction steel bar net 11. The length of the vertical shear reinforcement 10 extending into the inside of the support structure 3 should not be less than 10 times its own diameter, and the area Asv of the vertical shear reinforcement 10 should satisfy:

[0095] A sv ≥ 1.2V sub / (f dv · N k )

[0096] In the formula, V sub is the shear strength of the substructure, f dv is the tensile strength design value of the vertical steel bar, and N k is the number of locking blocks 6 on one bent cap.

[0097] Further, the locking groove 4 is the groove space between two adjacent locking blocks 6, and the concave surface remains flat. When the displacement of the T-beam 2 is too large, it will directly fall into the locking groove 4, so the transverse width W c of the locking groove 4 should satisfy:

[0098] W c = W mt + 50mm

[0099] In the formula, W mt is the width of the horse's hoof under the T-beam 2.

[0100] The present application relates to a T beam 2, an anchor bolted plate rubber bearing 5, an energy dissipation element 7, a reset spring 102, a locking block 6, a locking groove 4 and a support structure 3.

[0101] The overall connection installation mode of the construction features of the present application is that the cap beam and the top surface of the abutment cap of the bridge support structure 3 (including the pier and the abutment) are provided with locking blocks 6, the locking grooves 4 are formed between the locking blocks 6, the space size of the locking grooves 4 can just accommodate the lower horseshoe structure of the prestressed concrete T beam 2 so as to form a locked state; the anchor bolted plate rubber bearing 5 is fixedly connected with the locking blocks 6 through high-strength bolts, and the soft steel energy dissipation element 7 is fixed on the two outermost locking blocks 6 through anchor bolts; the prestressed concrete T beam 2 is directly placed on the anchor bolted plate rubber bearing 5 and directly contacts with the top surface of the anchor bolted plate rubber bearing 5 through the embedded steel plate at the bottom surface of the lower horseshoe; the soft steel energy dissipation element 7 is connected with the T beam 2 through a long screw rod 101, one end of the long screw rod 101 is directly fixed with the T beam 2, and the other end forms a bidirectional sliding connection state with the soft steel energy dissipation element 7 so as to adapt to the longitudinal temperature expansion and contraction deformation of the bridge and control the triggering time of the soft steel energy dissipation element 7; the spiral reset spring 102 penetrates through the long screw rod 101 and is fixed at one end with the T beam 2 and at the other end with the soft steel energy dissipation element 7.

[0102] The working conditions of each system are described below in combination with specific actual situations.

[0103] Specifically, when the seismic intensity is low, the anchor bolted plate rubber bearing 5 occurs elastic shear deformation, but the displacement of the T beam 2 is less than the elastic limit deformation Δ0 of the anchor bolted plate rubber bearing 5, the energy dissipation element 7 does not work, and the reset spring 102 generates a reset force F t = 2N t · k t · Δ, together with the flexible isolation effect of the anchor bolted plate rubber bearing 5 on the lower structure, a first-stage elastic isolation constraint system with reset ability is formed, that is, the first-stage constraint system starts to work.

[0104] When the seismic intensity increases, the displacement of the T beam 2 exceeds the elastic limit deformation Δ0 of the rubber bearing 5, but does not exceed the limit deformation of the energy dissipation element 7, that is, Δ0≤Δ<Δ0+Δ Eu , the T beam 2 and the rubber bearing 5 produce slip on the contact surface to form a slip isolation effect on the lower structure, and the energy dissipation element 7 plays a role of energy dissipation, together with the reset spring 102 generating a reset force, a second-stage slip isolation constraint system with reset and energy dissipation ability is formed, that is, the second-stage constraint system starts to work.

[0105] When the seismic intensity continues to increase, the slip displacement of the T beam 2 exceeds the limit deformation of the energy dissipation element 7, Δ≥Δ0+Δ Eu, the energy dissipation element 7 is out of work due to fracture, the T beam 2 falls into the locking groove 4 due to too large slip displacement and forms a fixed locking state with the support structure 3 through the locking block 6, and a third level of anti-falling beam locking constraint system, i.e., the third level of constraint system, starts to work.

[0106] When the seismic intensity further increases, the traditional ductility seismic mechanism of the support structure 3 starts to work through plastic hinges to dissipate energy, and a fourth level of ductility seismic system, i.e., the fourth level of constraint system, starts to work.

[0107] In addition, the specific working process of the structure is as follows: under the action of an earthquake, with the transmission of the inertia force of the T beam 2, the rubber bearing 5 starts to produce elastic shear deformation, forms a flexible isolation effect on the support structure 3, and drives the reset spring 102 on both sides to produce a reset force, since the stiffness of the reset spring 102 is significantly lower than that of the energy dissipation element 7, the energy dissipation element 7 does not work, at this time, the first level of elastic isolation constraint system with reset ability is composed of the flexible isolation of the rubber bearing 5 and the reset force of the reset spring 102; with the increase of the displacement of the T beam 2, the elastic shear deformation of the plate rubber bearing 5 reaches the limit, the T beam 2 slips on the top surface of the plate rubber bearing 5, and further forms a slip isolation state on the bridge support structure 3, at this time, the reset spring 102 reaches the limit compression amount, and the energy dissipation element 7 enters the plastic energy dissipation state, so that the second level of slip isolation constraint system with reset and energy dissipation ability is composed of the slip isolation of the rubber bearing 5, the reset force of the reset spring 102 and the plastic energy dissipation of the energy dissipation element 7; when the displacement of the T beam 2 exceeds the limit deformation of the energy dissipation element 7, the energy dissipation element 7 is out of work due to fracture, and the reset spring 102 also does not work due to the loss of one end constraint, at this time, the slip displacement of the T beam 2 is basically out of control, and soon falls into the locking groove 4, avoiding the occurrence of beam falling, and at the same time, a fixed locking state is formed through the locking block 6 and the lower structure, i.e., the third level of anti-falling beam locking constraint system; if the seismic motion is still increasing, the inertia force of the T beam 2 is transmitted to the support structure 3 due to the loss of isolation, triggering the pier column to quickly form a plastic hinge and dissipate energy, and finally forming a fourth level of ductility seismic system.

[0108] According to the structural characteristics and actual damage phenomena of small and medium span T-beam bridges in China, the traditional seismic reduction and isolation design method and the ductility design method are organically connected into a whole through ingenious design in geometric structure and mechanical principle. Firstly, the seismic energy is dissipated by the isolation and energy dissipation of connecting components and additional devices to reduce the damage of the main structure of the bridge under earthquake; when the earthquake energy is too large to be completely dissipated by the connecting components and additional devices, the plastic hysteresis energy dissipation mechanism of the pier is finally started to fully utilize the ductility seismic potential of the pier. This idea fully highlights the ordered cooperation relationship of each component in the bridge structure system, so as to mobilize the seismic potential of each component, and truly realize the multi-level seismic concept of "each component makes full use of its potential, takes advantage of the strong and compensates for the weak, and mutual cooperation".

[0109] The application combines the traditional seismic reduction and isolation idea and the ductility seismic idea, and connects four kinds of seismic mechanisms of "plate rubber bearing flexibility + sliding isolation", "limiting device resetting + energy dissipation", "anti-falling beam", and "pier plastic energy dissipation" into an orderly working whole through reasonable design of the seismic structure and constraint system of the T-beam bridge, so as to fully utilize the seismic potential of each component of the bridge, and realize the multi-level seismic concept of "each component makes full use of its potential, takes advantage of the strong and compensates for the weak, and mutual cooperation". The application does not change the traditional structure form of the small and medium span T-beam bridge, is convenient for designers to accept and understand, and has the advantages of simple structure, low cost, convenient construction, and quick replacement after earthquake in the T-beam bridge with large quantity and wide range, and has a wide application prospect.

[0110] The above is only the preferred embodiment of the application, and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A bridge seismic resistance method with multi-level ordered reset energy dissipation, characterized in that, include; The first-level restraint system includes rubber bearings and a reset assembly. The rubber bearings are used to connect between the support structure and the T-beam, and the reset assembly is used to connect with the T-beam to dissipate vibration energy. The first-level restraint system starts working when ground vibration begins. The second-level restraint system includes energy-dissipating elements that are connected to the T-beam to dissipate vibration energy. The second-level restraint system starts working when ground vibration intensifies. The third-level restraint system includes several locking blocks and locking slots. The locking blocks are disposed on the support structure. The energy-dissipating elements are disposed on the locking blocks located on both sides of the support structure. The remaining locking blocks are connected to the bottom of the rubber support. The gap between adjacent locking blocks forms the locking slot. When the ground vibration further intensifies, the third-level restraint system starts to work. The fourth-level constraint system includes a support structure, which includes piers and abutments. When ground vibration continues to increase, the support structure forms a plastic hinge and dissipates energy through hysteresis, and the fourth-level constraint system starts to work. The first-level restraint system, the second-level restraint system, the third-level restraint system, and the fourth-level restraint system start working sequentially according to the ground vibration intensity; The energy-consuming element includes several second steel plates with through holes in the middle. The upper end of the second steel plate is connected to the reset assembly by a second bolt, and the lower end of the second steel plate is connected to a connecting groove by a second bolt. The connecting groove is connected to the locking block by a third bolt. The shear strength of the second bolt is: The shear strength of the third bolt is: The design limit strength of the energy-consuming element is: The lateral limit deformation of the second steel plate is: In the above formula, The ultimate strength of the second steel plate. N E This refers to the number of the second steel plates in an energy-consuming component. n r1 This refers to the number of high-strength bolts used in a single perforated mild steel sheet. n r2 The number of anchor bolts used in a single mild steel energy dissipation element. h The height of the porous mild steel plate. σ u The ultimate stress of the porous mild steel plate, b、t For the width and thickness of the porous mild steel sheet, θ This is the limit deformation angle; The reset assembly includes a reset spring, a bidirectional slide groove, and a screw. The bidirectional slide groove is connected to the top of the second steel plate, and the screw is slidably connected within the bidirectional slide groove. The reset spring is sleeved on the screw. One end of the screw is provided with a retaining ring for limiting the position, and the other end is provided with a nut. One end of the reset spring is connected to the bidirectional slide groove, and the other end is connected to the T-beam.

2. A bridge seismic-resistant structure with multi-level ordered reset energy dissipation, comprising the bridge seismic-resistant method with multi-level ordered reset energy dissipation as described in claim 1, characterized in that, The conditions for the first-level constraint system to start working are: Δ<Δ0 In the above formula, Δ is the displacement of the T-beam, and Δ0 is the elastic limit deformation of the rubber support.

3. A bridge seismic-resistant structure with multi-level ordered reset energy dissipation according to claim 2, characterized in that, The bottom of the rubber support is provided with a first steel plate, which is connected to the locking block by a first bolt. The shear strength of the first bolt is: In the above formula, Q b The shear strength of the first bolt. F f This is the sum of the static friction forces of all rubber bearings. N b The number of rubber bearings on each pier. n b The number of first bolts used for a single rubber bearing.

4. A bridge seismic-resistant structure with multi-level ordered reset energy dissipation according to claim 3, characterized in that, The conditions for the second-level constraint system to start working are: Δ0≤Δ<Δ0+Δ Eu In the above formula, Δ Eu This represents the ultimate deformation of energy-consuming components.

5. A bridge seismic-resistant structure with multi-level ordered reset energy dissipation according to claim 4, characterized in that, The distance between the retaining ring and the nut is: The width and height of the through hole for screw sliding on the bidirectional slide groove are as follows: The inner diameter, ultimate compression, and stiffness of the return spring are as follows: In the formula, W E The length of the bidirectional groove is given, and Δ0 is the elastic limit deformation of the rubber support. d g Let Δ be the diameter of the screw. ej To accommodate the expansion and contraction of the structure corresponding to or near the expansion joint. d t Δ is the inner diameter of the return spring. t This represents the maximum compression of the return spring. k t To provide the stiffness of the return spring, h Ec The groove opening height of the bidirectional chute is [height]. H b The height of the rubber bearing. K ES Let be the initial elastic stiffness of the second steel plate. N g The number of screws. N g ≥3.

6. A bridge seismic-resistant structure with multi-level ordered reset energy dissipation according to claim 5, characterized in that, The locking block is surrounded by a steel mesh and vertically arranged shear reinforcement bars. The shear reinforcement bars are located within the supporting structure, and their length is greater than ten times their diameter. The third-level constraint system begins to function under the following conditions: Δ≥Δ0+Δ Eu The height of the locking block is: The area of ​​the shear reinforcement is: In the formula, H mt The height of the horseshoe-shaped support under the T-beam. H b The height of the rubber bearing. V sub To support the shear strength of the structure, f dv This represents the design value of the tensile strength of the shear reinforcement. N k The number of locked blocks.

7. A bridge seismic-resistant structure with multi-level ordered reset energy dissipation according to claim 6, characterized in that, The width of the locking slot is: In the formula, W mt The width of the horseshoe-shaped support under the T-beam.

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