Design method and construction method for earthquake prevention and disaster reduction of T-shaped rigid frame bridge

Abstract

The invention relates to the technical field of disaster prevention and reduction, in particular to a design method and a construction method for earthquake prevention and disaster reduction of a T-shaped rigid frame bridge. According to the design method, a swing energy dissipation and shock absorption device is added in the design process of the T-shaped rigid frame bridge, collaborative optimization is carried out, so that the T-shaped rigid frame bridge does not have plastic damage under the action of an earthquake exceeding fortification intensity; the swing energy dissipation and seismic mitigation device dissipates seismic energy, reduces the seismic energy transmitted from the foundation and the bearing platform to the bridge piers and the main beam, reduces the seismic force of the bridge piers, reduces the displacement and flapping effect of the main beam, and protects the operation safety of the T-shaped rigid frame bridge.

Description

Technical Field

[0001] The invention relates to the technical field of disaster prevention and reduction, in particular to a seismic disaster reduction design method and a construction method for a T-shaped rigid frame bridge. Background Art

[0002] In order to cross complex mountainous areas, super-high pier T-shaped rigid frame bridges are often used for crossing. However, the active fault zones in the southwestern mountainous areas are densely distributed and earthquakes occur frequently. The seismic resistance problem of super-high pier T-shaped rigid frame bridges is very prominent. Due to the particularity of T-shaped rigid frame bridges, for T-shaped rigid frame bridges with pier heights exceeding 50m, during an earthquake, the piers will experience excessive horizontal displacement and seismic damage, the main beams will undergo large vertical and lateral deformations, and the supports on both sides will easily become detached and damaged under the action of an earthquake. The ends of the main beams will "beat" the abutments, and the impact force on the main beams during the beating process is relatively large. In severe cases, the main beams will crack or collapse.

[0003] Scholars at home and abroad have conducted a lot of research on the seismic resistance of T-shaped rigid frame bridges. Due to its special structure, namely pier-beam consolidation, the T-shaped rigid frame bridge mainly relies on the piers to bear the seismic force under the action of an earthquake. The piers are damaged and energy is consumed, causing destruction. Once the piers of the T-shaped rigid frame bridge are plastically damaged under the action of an earthquake, the main beam will undergo large displacement, and the piers will be difficult to repair and reset after being damaged.

[0004] The seismic design method currently adopted at home and abroad is: directly design the cross-sectional dimensions and reinforcement ratio of the T-shaped rigid frame bridge piers, calculate the seismic force of the pier structure under the action of E1 and E2 earthquakes by finite element calculation, and then use the design specifications of each country to verify whether the bending, shear, torsion and other forces of the pier cross-section meet the requirements, so that the piers do not enter a plastic state under the action of the earthquake.

[0005] However, once the actual earthquake intensity exceeds the seismic intensity specified in the design specifications, the piers are prone to enter a plastic state, swing violently, and suffer damage, as the piers themselves are generally made of reinforced concrete, which has weak energy absorption capacity. At this time, post-earthquake repairs are very difficult.

[0006] Some scholars have adopted a large-section pier structure, which has improved the bending and shear bearing capacity of the piers. However, due to the increase in the stiffness of the piers, the seismic force on the piers and the foundation has increased, making the foundation design difficult.

[0007] Some scholars have installed seismic isolation bearings, viscous dampers, metal dampers and other devices on both sides of the T-shaped rigid frame bridge. However, since the main seismic deformation of the T-shaped rigid frame bridge is in the form of "cantilever" swinging of the piers and beating of the abutments, and the above-mentioned shock-absorbing and energy-absorbing measures are directional, they cannot solve the problems of the three-dimensional seismic spatial deformation and beating effect of the T-shaped rigid frame bridge piers.

[0008] Therefore, in order to ensure the seismic performance of T-shaped rigid frame bridges, reduce the risk of seismic plastic failure of T-shaped rigid frame bridge piers, reduce the displacement of main beams and reduce the phenomenon of main beam ends hitting abutments, a new seismic design method for T-shaped rigid frame bridges is needed. Summary of the invention

[0009] The purpose of the present invention is to provide a seismic disaster reduction design method and a construction method for a T-shaped rigid frame bridge in view of the pier-beam consolidation of the T-shaped rigid frame bridge in the prior art. Under the action of an earthquake, the seismic force is mainly borne by the piers. Once the piers of the T-shaped rigid frame bridge are plastically damaged under the action of an earthquake, it is difficult to repair and reset them. At the same time, the main beam will undergo a large displacement, resulting in an unfavorable state in which the end of the main beam hits the abutment.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] In a first aspect, the present invention provides a method for earthquake-resistant and disaster-reducing design of a T-shaped rigid frame bridge, comprising the following steps:

[0012] S1. A swing energy absorption and shock absorbing device is arranged around the top of the pedestal of the T-shaped rigid frame bridge. The swing energy absorption and shock absorbing device comprises a counterweight beam and a plastic energy absorption rod. The top of the plastic energy absorption rod is connected to the counterweight beam and the bottom is connected to the pedestal. The plastic energy absorption rod is a soft metal rod.

[0013] The mass of the counterweight beam is M1, the mass of the main beam of the T-shaped rigid frame bridge is M2, the mass of the pier is M3, the pier-beam connection stiffness is K2, and the pier stiffness is K3;

[0014] According to the platform section of the earthquake zone design response spectrum, the initial value of the earthquake force of the swing energy dissipation and shock absorption device F(1)=S max ×M1, where S max is the maximum value of the design acceleration response spectrum;

[0015] S2, assuming that the yield displacement design value of the plastic energy-absorbing rod under the initial value of the earthquake force F(1) is S 1y , by S 1y =F(1) / n×H 3 / (3×E×I), solve the initial value K(1) of the elastic stiffness value K(i) of the plastic energy dissipation rod, where n is the number of the plastic energy dissipation rods, H is the height of the plastic energy dissipation rod, E is the elastic modulus, and I is the section inertia moment;

[0016] According to K(1), the specific structure of the plastic energy dissipation rod is optimized and designed;

[0017] S3. Based on the deadweight and stiffness of the main beam and the bridge pier, the elastic stiffness value of the swing energy dissipation and shock absorption device, and the simplified dynamic characteristic calculation model of the T-shaped rigid frame bridge and the swing energy dissipation and shock absorption device, the finite element method is used to solve the characteristic value of the T-shaped rigid frame bridge and the initial value t(1) of the structural natural vibration period;

[0018] S4. The characteristic period of the entire T-shaped rigid frame bridge is t(i), and the first-order characteristic period is the initial value of the natural vibration period of the structure t(1). The seismic force Fz(i) borne by the T-shaped rigid frame bridge and the seismic force F(i) of the plastic energy-absorbing rod are solved through the response spectrum curve, where i=1, 2, 3...;

[0019] S5. According to the earthquake force Fz(i) borne by the bridge and the seismic design specifications for bridges, verify whether the bearing capacity of each bridge component meets the requirements of the specifications, and verify whether the deformation stiffness of the T-shaped rigid frame bridge meets the requirements of the specifications;

[0020] If the requirements are not met, adjust the cross-sectional dimensions or reinforcement conditions of the bridge components, and update the values ​​of M2, M3 and K2, K3 accordingly, and repeat step S3;

[0021] If the requirements are met, the yield displacement of the plastic energy-absorbing rod under the action of the earthquake force F(i) is solved, and the elastic stiffness value K(i) of the plastic energy-absorbing rod is solved;

[0022] S6, substituting the new elastic stiffness value K(i) of the plastic energy-absorbing rod and the updated values ​​of M2, M3 and K2, K3 into step S3, using the finite element method to solve the characteristic value of the T-shaped rigid frame bridge, the natural vibration period t(i+1) of the bridge structure can be obtained, and the seismic force Fz(i+1) of the bridge and the seismic force F(i+1) of the plastic energy-absorbing rod can be obtained through the response spectrum curve;

[0023] S7. Error in seismic force borne by the bridge ε is the preset requirement;

[0024] If the requirement is not met, increase the weight of the counterweight beam by a percentage of the original weight, reduce the weight of the main beam, repeat step S3, and recalculate Fz(i+1) until the requirement is met;

[0025] S8, adjusting the obtained seismic force F(i+1) of the plastic energy absorbing rod down by 20%-30% as the design yield load, obtaining the yield load of each plastic energy absorbing rod, solving the yield displacement of the plastic energy absorbing rod, re-obtaining the elastic stiffness K(i+1)×n of the swing energy absorbing and shock absorbing device, and completing the design of the swing energy absorbing and shock absorbing device and the design of the bridge pier cross section;

[0026] S9. Use the finite element method to establish the constitutive model of the whole bridge and the swing energy dissipation and shock absorption device, calculate the deformation value D1 of the T-shaped rigid frame beam end including the swing energy dissipation and shock absorption device and the deformation value D2 of the original bridge end, set the optimization target of the seismic deformation of the original bridge at the beam end of the T-shaped rigid frame bridge, and carry out the design of the counterweight beam;

[0027] When the seismic displacement of the beam end fails to reach the design target, the mass M1 of the counterweight beam is increased gradually by percentage of the original mass until the deformation of the beam end meets the optimization target.

[0028] The earthquake prevention and disaster reduction design method for a T-shaped rigid frame bridge described in the present invention is adopted. By adding a swing energy dissipation and shock absorption device during the design process of the T-shaped rigid frame bridge and performing coordinated optimization, the T-shaped rigid frame bridge will not suffer plastic damage under the action of an earthquake exceeding the design intensity. The swing energy dissipation and shock absorption device dissipates seismic energy, reduces the transmission of seismic energy from the foundation and the abutment to the piers and the main beam, reduces the seismic force on the piers, reduces the displacement and slapping effect of the main beam, and protects the operational safety of the T-shaped rigid frame bridge; at the same time, the swing energy dissipation and shock absorption device can also prevent other disasters, such as preventing falling rocks from hitting the piers.

[0029] As a preferred technical solution of the present invention, in step S1, the swing energy dissipation and shock absorption device also includes an anti-collision elastic member, the anti-collision elastic member is connected to the inner side of the counterweight beam, and there is a distance between the anti-collision elastic member and the outer wall of the pier.

[0030] As a further preferred technical solution of the present invention, in step S2, when the relative displacement between the plastic energy dissipation rod and the bridge pier reaches the design value S 1y When the anti-collision elastic member takes effect, the initial stiffness K of the anti-collision elastic member T Designed to be an integer multiple of K(1).

[0031] As a further preferred technical solution of the present invention, in step S8, after obtaining the yield displacement of the plastic energy dissipation rod, the stiffness K of the anti-collision elastic member is re-determined. T , and the design value of the distance between the anti-collision elastic part and the bridge pier.

[0032] As a further preferred technical solution of the present invention, the anti-collision elastic member is a spring and / or a rubber pad.

[0033] As a preferred technical solution of the present invention, in step S1, the plastic energy dissipation rod is made of a solid soft steel rod or a hollow soft steel tube, and the material is required to have an elongation after fracture greater than 40% and an impact absorption energy greater than 120J.

[0034] As a preferred technical solution of the present invention, in step S7, if the requirements are not met, the weight of the counterweight beam is increased by 10% of the original weight.

[0035] As a preferred technical solution of the present invention, in step S9, the optimization goal is to reduce the seismic deformation of the original bridge at the beam end of the T-shaped rigid frame bridge by more than 50%.

[0036] In a second aspect, the present invention further provides a construction method for a T-shaped rigid frame bridge, comprising the following steps:

[0037] Construction of T-shaped rigid frame bridge cap;

[0038] A swing energy absorption and shock absorbing device is arranged on the supporting platform, and the swing energy absorption and shock absorbing device comprises a counterweight beam and a plastic energy absorption rod. The top of the plastic energy absorption rod is connected to the counterweight beam, and the bottom is connected to the supporting platform. The plastic energy absorption rod is a solid soft metal rod.

[0039] In a third aspect, the present invention further provides a T-shaped rigid frame bridge, which is designed using the earthquake-resistant and disaster-reducing design method for a T-shaped rigid frame bridge as described in any one of the above items, or constructed using the construction method for a T-shaped rigid frame bridge as described in any one of the above items.

[0040] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0041] The present invention discloses a method for earthquake prevention and disaster reduction design of a T-shaped rigid frame bridge. In the design process of the T-shaped rigid frame bridge, a swing energy dissipation and shock absorption device is added, and coordinated optimization is performed, so that the T-shaped rigid frame bridge does not suffer plastic damage and destruction under the action of an earthquake exceeding the design intensity. The swing energy dissipation and shock absorption device dissipates earthquake energy, reduces the transmission of earthquake energy from the foundation and the abutment to the piers and the main beam, reduces the earthquake force on the piers, reduces the displacement and slapping effect of the main beam, and protects the operational safety of the T-shaped rigid frame bridge. At the same time, the swing energy dissipation and shock absorption device can also prevent other disasters, such as preventing falling rocks from hitting the piers. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of the seismic disaster reduction design method for T-shaped rigid frame bridge;

[0043] Figure 2 Structural schematic diagram of setting a swing energy dissipation and vibration reduction device for a T-shaped rigid frame bridge;

[0044] Figure 3 It is a structural schematic diagram of the swing energy dissipation and shock absorption device;

[0045] Figure 4 for Figure 3 Middle AA section view;

[0046] Figure 5 Design response spectrum diagrams for seismic areas;

[0047] Figure 6 A simplified calculation model for the characteristic period of a T-shaped rigid frame bridge based on rocking energy dissipation is proposed.

[0048] Markings in the figure: 1-counterweight beam, 2-main beam, 3-pier, 4-cap, 5-plastic energy absorption rod, 6-transverse connecting piece, 7-anti-collision elastic piece, 8-foundation, 9-anchor, 10-base plate, 11-first bolt, 12-second bolt, 13-top base plate. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0050] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0051] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0052] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0053] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0054] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0055] In the related art, the piers and beams of a T-shaped rigid frame bridge are consolidated, and the seismic force is mainly borne by the piers under the action of an earthquake. Once the piers of a T-shaped rigid frame bridge are plastically damaged under the action of an earthquake, it is difficult to repair and reset them. At the same time, the main beam will be greatly displaced, resulting in an unfavorable state where the end of the main beam hits the abutment. For this reason, the technical solution of this application is produced, and the following is combined with Figures 1 to 6 To elaborate.

[0056] Example 1

[0057] like Figures 1 to 6 As shown, the earthquake prevention and disaster reduction design method of a T-shaped rigid frame bridge described in the present invention comprises the following steps:

[0058] Step 1: Figures 2 to 4 As shown, a multi-degree-of-freedom swing energy absorption and shock absorption device is arranged around the top of the pedestal 4 of the T-shaped rigid frame bridge, and the device includes a counterweight beam 1, a plastic energy absorption component, a transverse connection component 6, and an anti-collision elastic component 7, wherein the plastic energy absorption component includes a plurality of plastic energy absorption rods 5, the top of the plastic energy absorption rod 5 is connected to the counterweight beam 1, and the bottom is connected to the pedestal 4, and the plastic energy absorption rod 5 is made of soft metal rods, such as solid soft steel rods or hollow soft steel pipes.

[0059] In some optional implementations, the plastic energy dissipation rod 5 is made of round mild steel, and the material is required to have an elongation after fracture greater than 40% and an impact absorption energy greater than 120J.

[0060] In some optional embodiments, the bottom and top of each plastic energy dissipation rod 5 are respectively connected to a base plate 10 and a top seat plate 13, the plastic energy dissipation rod 5 is connected to the pedestal 4 through the base plate 10, and the plastic energy dissipation rod 5 is connected to the counterweight beam 1 through the top seat plate 13. Specifically, an anchor 9 is provided in the pedestal 4, the base plate 10 is connected to the anchor 9 through a first bolt 11, and the top seat plate 13 is connected to the counterweight beam 1 through a second bolt 12.

[0061] In some optional embodiments, the counterweight beam 1 is configured as a rectangular frame, enclosed around the pier 3 of the T-shaped rigid frame bridge, and a plurality of anti-collision elastic members 7 are connected to the inner side of the counterweight beam 1, and there is a distance between the anti-collision elastic members 7 and the outer wall of the pier 3. Specifically, the four parts of the rectangular counterweight beam 1 can be connected by welding or bolting; the anti-collision elastic member 7 can be a spring (a pad is provided at one end of the spring facing the pier 3), or a rubber pad, or a spring and a rubber pad can be provided at the same time; each part of the rectangular counterweight beam 1 is provided with two anti-collision elastic members 7.

[0062] In some optional embodiments, a plurality of plastic energy-absorbing rods 5 arranged in a row are connected as a whole via at least one transverse connecting member 6 .

[0063] In some optional implementations, the pier 3 of the T-shaped rigid frame bridge uses a solid pier in the part where the swing energy dissipation and shock absorption device is arranged, and the part above it can use a hollow thin-walled pier.

[0064] The mass of the counterweight beam 1 is M1, the mass of the main beam 2 of the T-shaped rigid frame bridge is M2, the mass of the pier 3 is M3, the mass of the abutment 4 is M4, the pier-beam connection stiffness is K2, the pier 3 stiffness is K3, the foundation 8 stiffness is K4, and the side span connection stiffness is K5.

[0065] Assume that the natural vibration period corresponding to the initial elastic stiffness is in the design response spectrum of the earthquake zone (such as Figure 5 The initial value of the seismic force of the swing energy dissipation and shock absorption device is obtained by looking at the platform section of the curve (shown in Figure 1) = S max ×M1, where S max To design the maximum value of the acceleration response spectrum, M1 is the initial mass of the counterweight beam 1, which is generally 1 / 120 to 1 / 100 of the weight of the pier 3.

[0066] Step 2: In the elastic working stage, the design value of the yield displacement of the plastic energy dissipation rod 5 under the initial value of the earthquake force F(1) is S 1y , according to experience S 1y Generally, 1 / 3 of the deformation of pier 3 is taken, and S 1y =F(1) / n×H 3 / (3×E×I), solve the initial value K(1) of the elastic stiffness value K(i) of the plastic energy absorbing rod 5, where n is the number of plastic energy absorbing rods 5, H is the height of the plastic energy absorbing rod 5, E is the elastic modulus, and I is the section inertia moment.

[0067] According to K(1), the specific structure of the plastic energy dissipation rod 5 in the swing energy dissipation and shock absorption device (including cross-sectional dimensions such as circular diameter D, height H, and number n) is optimized and designed. When the relative displacement between the plastic energy dissipation rod 5 and the bridge pier 3 reaches the design value S 1y When the anti-collision elastic member 7 takes effect, the initial stiffness K of the anti-collision elastic member 7 is TIt is designed to be an integer multiple of K(1), for example, K(1)×10.

[0068] Step 3: Based on the deadweight and stiffness of the main beam 2 and the pier 3 of the T-shaped rigid frame bridge, the elastic stiffness value of the swing energy dissipation and shock absorption device, and the simplified dynamic characteristic calculation model of the T-shaped rigid frame bridge and the swing energy dissipation and shock absorption device (such as Figure 6 As shown in Figure 2, the finite element method is used to solve the characteristic values ​​of the T-shaped rigid frame bridge and the initial value of the natural vibration period of the structure t(1).

[0069] Step 4: The characteristic period of the entire T-shaped rigid frame bridge is t(i), and the first-order characteristic period is the initial value of the structure's natural vibration period t(1). Through the response spectrum curve, the seismic force Fz(i) borne by the T-shaped rigid frame bridge and the seismic force F(i) of the plastic energy-absorbing rod 5 are solved, where i=1, 2, 3..., and the initial value of the seismic force of the T-shaped rigid frame bridge is Fz(1).

[0070] Step 5. Based on the seismic force Fz(i) borne by the bridge and the current bridge seismic design specifications, verify whether the bending, shear and torsion resistance of the cross-section of each bridge component meets the requirements of the specifications, and verify whether the deformation stiffness of the T-shaped rigid frame bridge meets the requirements of the specifications.

[0071] If the requirements are not met, adjust the cross-sectional dimensions or reinforcement conditions of the key components of the bridge until they are met. At this time, the cross-sectional dimensions and mass of the key components of the bridge have changed, and the M2, M3 and K2, K3 values ​​need to be updated accordingly, and step three should be repeated.

[0072] If the requirements are met, the yield displacement of the plastic energy absorbing rod 5 under the action of the earthquake force F(i) is solved, and the elastic stiffness value K(i) of the plastic energy absorbing rod 5 is solved.

[0073] Step 6. Substitute the new elastic stiffness value K(i) of the plastic energy absorbing rod 5 and the updated values ​​of M2, M3, K2 and K3 into step 3, and use the finite element method to solve the characteristic value of the T-shaped rigid frame bridge to obtain the natural vibration period t(i+1) of the bridge structure. Through the response spectrum curve, the seismic force Fz(i+1) of the bridge and the seismic force F(i+1) of the plastic energy absorbing rod 5 are obtained.

[0074] Step 7. Error of seismic force borne by the bridge ε is the preset requirement. According to engineering experience, ε can be taken as 5%.

[0075] If the requirements are not met, increase the weight of the counterweight beam 1 by 10% of the original weight, appropriately reduce the weight of the main beam 2, repeat step 3, and recalculate Fz(i+1) until the requirements are met.

[0076] Step 8: Adjust the obtained seismic force F(i+1) of the plastic energy dissipation rod 5 down by 20%-30% as the design yield load, obtain the yield load of each plastic energy dissipation rod 5, solve the yield displacement of the plastic energy dissipation rod 5, re-obtain the elastic stiffness K(i+1)×n of the swing energy dissipation and shock absorption device, and re-determine the stiffness K of the anti-collision elastic member 7. T , as well as the design value of the distance between the anti-collision elastic member 7 and the pier 3, the design of the swing energy dissipation and shock absorption device and the design of the cross section of the pier 3 are completed.

[0077] Step nine, establish the constitutive model of the whole bridge and the swing energy dissipation and shock absorption device (the T-shaped rigid frame bridge adopts a three-dimensional beam unit model, the nonlinear model of the side span support is considered, the plastic energy dissipation rod 5 in the swing energy dissipation and shock absorption device adopts nonlinear constitutive simulation, and the counterweight beam 1 adopts mass block simulation).

[0078] A time-history analysis was carried out (the results of three rare earthquakes were calculated and the average value was taken for analysis), and the difference between the deformation value D1 of the side span support of the T-shaped rigid frame after the swing energy dissipation and shock-absorbing device was installed and the deformation value D2 of the original bridge was compared. With the optimization goal of reducing the seismic deformation of the original bridge at the beam end of the T-shaped rigid frame bridge by more than 50%, the design of the top counterweight beam 1 of the swing energy dissipation and shock-absorbing device was carried out.

[0079] When the seismic displacement at the beam end fails to reach the design target, the mass M1 of the counterweight beam 1 of the swing energy dissipation and shock absorption device is increased by 10% of the original mass gradually until the displacement deformation is reduced by more than 50%. The design is completed, the seismic design of the T-shaped rigid frame bridge is realized, and the flapping effect problem is solved.

[0080] T-shaped rigid frame bridges are generally built in high mountain valleys. The bridge piers 3 are very high, and rocks are prone to fall from the mountains on both sides of the valley. The swing energy dissipation and shock absorption device can prevent the falling rocks from hitting the bridge piers 3 and causing damage.

[0081] The present embodiment describes a method for earthquake prevention and disaster reduction design of a T-shaped rigid frame bridge. By adding a swing energy dissipation and shock absorption device during the design process of the T-shaped rigid frame bridge and performing coordinated optimization, the T-shaped rigid frame bridge will not suffer plastic damage under the action of an earthquake exceeding the design intensity. The swing energy dissipation and shock absorption device dissipates earthquake energy, reduces the transmission of earthquake energy from the foundation 8 and the pedestal 4 to the pier 3 and the main beam 2, reduces the earthquake force on the pier 3, reduces the displacement and flapping effect of the main beam 2, and protects the operational safety of the T-shaped rigid frame bridge. At the same time, the swing energy dissipation and shock absorption device can also prevent other disasters, such as preventing falling rocks from hitting the pier 3.

[0082] Example 2

[0083] like Figures 2 to 4 As shown, the construction method of a T-shaped rigid frame bridge described in the present invention utilizes the earthquake-proof and disaster-reduction design method of a T-shaped rigid frame bridge described in Example 1 to design the T-shaped rigid frame bridge.

[0084] The construction method comprises the following steps:

[0085] A1. During the construction of the pier 4 of the T-shaped rigid frame bridge, pre-embed the anchor 9. The anchor 9 can be a U-shaped anchor bar with a threaded sleeve connected to the end of the U-shaped anchor bar. The anchor 9 serves as the basis for installing the swing energy dissipation and shock absorption device. After the construction of the pier 3 is completed, the swing energy dissipation and shock absorption device is installed.

[0086] A2. Install the plastic energy absorbing component, which includes a plurality of plastic energy absorbing rods 5. The top of the plastic energy absorbing rod 5 is provided with a top seat plate 13 and the bottom is provided with a base plate 10. The plastic energy absorbing rods 5 are installed one by one, and the base plate 10 is connected to the anchor 9 by a first bolt 11.

[0087] A3. Install the transverse connecting member 6. The transverse connecting member 6 is connected to the plastic energy dissipation rod 5 by welding, and the plastic energy dissipation components are connected together to form a whole.

[0088] A4. Use a truck crane to hoist four counterweight beams 1 (the counterweight beams 1 are made of solid steel sections with counterweight blocks filled in the hollow sections) one by one onto the top of the plastic energy absorbing component, connect them to the top seat plate 13 of the plastic energy absorbing component through the second bolts 12, and then weld each hoisted counterweight beam 1 to the counterweight beam 1 that has been hoisted to form a rectangular frame of counterweight beams 1.

[0089] A5. After the counterweight beam 1 is installed, install the anti-collision spring and anti-collision elastic parts 7 one by one. The anti-collision elastic parts 7 can be made of springs (a pad is provided at the end of the spring facing the pier 3), or rubber pads, or springs and rubber pads can be set at the same time.

[0090] Example 3

[0091] like Figures 2 to 4 As shown, a T-shaped rigid frame bridge described in the present invention is designed using the earthquake prevention and disaster reduction design method of a T-shaped rigid frame bridge described in Example 1 or is constructed using the construction method of a T-shaped rigid frame bridge described in Example 2.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for earthquake-proof and disaster-reduction design of a T-shaped rigid frame bridge, characterized in that: The following steps are involved: S1. A swing energy absorption and shock absorbing device is arranged around the top of the pedestal (4) of the T-shaped rigid frame bridge, wherein the swing energy absorption and shock absorbing device comprises a counterweight beam (1) and a plastic energy absorption rod (5), wherein the top of the plastic energy absorption rod (5) is connected to the counterweight beam (1) and the bottom is connected to the pedestal (4), and the plastic energy absorption rod (5) is a soft metal rod; The mass of the counterweight beam (1) is M1, the mass of the main beam (2) of the T-shaped rigid frame bridge is M2, the mass of the pier (3) is M3, the pier-beam connection stiffness is K2, and the stiffness of the pier (3) is K3; According to the platform section of the earthquake zone design response spectrum, the initial value of the earthquake force of the swing energy dissipation and shock absorption device F(1)=S max ×M1, where S max is the maximum value of the design acceleration response spectrum; S2. Assume that the yield displacement design value of the plastic energy-absorbing rod (5) under the action of the initial value of the earthquake force F(1) is S 1y , by S 1y =F(1) / n×H 3 / (3×E×I), solve for the initial value K(1) of the elastic stiffness value K(i) of the plastic energy absorbing rod (5), where n is the number of the plastic energy absorbing rods (5), H is the height of the plastic energy absorbing rod (5), E is the elastic modulus, and I is the section inertia moment; Optimizing and designing the specific structure of the plastic energy dissipation rod (5) according to K (1); S3, based on the deadweight and stiffness of the main beam (2) and the bridge pier (3), the elastic stiffness value of the swing energy dissipation and shock absorption device, and the simplified dynamic characteristic calculation model of the T-shaped rigid frame bridge and the swing energy dissipation and shock absorption device, the finite element method is used to solve the characteristic value of the T-shaped rigid frame bridge and the initial value t(1) of the structural natural vibration period; S4, the characteristic period of the entire T-shaped rigid frame bridge is t(i), the first-order characteristic period is the initial value of the natural vibration period of the structure t(1), and the seismic force Fz(i) borne by the T-shaped rigid frame bridge and the seismic force F(i) of the plastic energy dissipation rod (5) are solved through the response spectrum curve, where i=1, 2, 3...; S5. According to the earthquake force Fz(i) borne by the bridge and the seismic design specifications for bridges, verify whether the bearing capacity of each bridge component meets the requirements of the specifications, and verify whether the deformation stiffness of the T-shaped rigid frame bridge meets the requirements of the specifications; If the requirements are not met, adjust the cross-sectional dimensions or reinforcement conditions of the bridge components, and update the values ​​of M2, M3 and K2, K3 accordingly, and repeat step S3; If the requirements are met, the yield displacement of the plastic energy absorbing rod (5) under the action of the earthquake force F(i) is solved, and the elastic stiffness value K(i) of the plastic energy absorbing rod (5) is solved; S6, substituting the new elastic stiffness value K(i) of the plastic energy absorbing rod (5) and the updated values ​​of M2, M3 and K2, K3 into step S3, using the finite element method to solve the characteristic value of the T-shaped rigid frame bridge, the natural vibration period t(i+1) of the bridge structure can be obtained, and the seismic force Fz(i+1) of the bridge and the seismic force F(i+1) of the plastic energy absorbing rod (5) can be obtained through the response spectrum curve; S7. Error in seismic force borne by the bridge ε is the preset requirement; If the requirement is not met, increase the weight of the counterweight beam (1) by a percentage of the original weight, reduce the weight of the main beam (2), repeat step S3, and recalculate Fz(i+1) until the requirement is met; S8, adjusting the obtained seismic force F(i+1) of the plastic energy absorbing rod (5) by 20%-30% as the design yield load, obtaining the yield load of each plastic energy absorbing rod (5), solving the yield displacement of the plastic energy absorbing rod (5), re-obtaining the elastic stiffness K(i+1)×n of the swing energy absorbing and shock absorbing device, and completing the design of the swing energy absorbing and shock absorbing device and the design of the cross section of the bridge pier (3); S9, using the finite element method to establish the constitutive model of the whole bridge and the swing energy dissipation and shock absorption device, respectively calculating the deformation value D1 of the T-shaped rigid frame beam end including the swing energy dissipation and shock absorption device and the deformation value D2 of the original bridge end, setting the optimization target of the seismic deformation of the original bridge at the T-shaped rigid frame bridge beam end, and carrying out the design of the counterweight beam (1); When the seismic displacement of the beam end fails to reach the design target, the mass M1 of the counterweight beam (1) is increased in succession according to the percentage of the original mass until the deformation of the beam end meets the optimization target.

2. The earthquake-proof and disaster-reduction design method for a T-shaped rigid frame bridge according to claim 1 is characterized in that: In step S1, the sway energy dissipation and shock absorption device further comprises an anti-collision elastic member (7), wherein the anti-collision elastic member (7) is connected to the inner side of the counterweight beam (1), and there is a distance between the anti-collision elastic member (7) and the outer wall of the pier (3).

3. The earthquake-proof and disaster-reduction design method for a T-shaped rigid frame bridge according to claim 2 is characterized in that: In step S2, when the relative displacement between the plastic energy dissipation rod (5) and the bridge pier (3) reaches the design value S 1y When the anti-collision elastic member (7) comes into play, the initial stiffness K of the anti-collision elastic member (7) is T Designed to be an integer multiple of K(1).

4. The earthquake-proof and disaster-reduction design method for a T-shaped rigid frame bridge according to claim 3 is characterized in that: In step S8, after obtaining the yield displacement of the plastic energy dissipation rod (5), the stiffness K of the anti-collision elastic member (7) is re-determined. T , and the design value of the distance between the anti-collision elastic member (7) and the bridge pier (3).

5. The earthquake-proof and disaster-reduction design method for a T-shaped rigid frame bridge according to claim 2, characterized in that: The anti-collision elastic member (7) is a spring and / or a rubber pad.

6. The earthquake-proof and disaster-reduction design method for a T-shaped rigid frame bridge according to claim 1, characterized in that: In step S1, the plastic energy dissipation rod (5) is made of a solid soft steel rod or a hollow soft steel tube, and the material is required to have an elongation after fracture greater than 40% and an impact absorption energy greater than 120J.

7. The earthquake-proof and disaster-reduction design method for a T-shaped rigid frame bridge according to claim 1, characterized in that: In step S7, if the requirements are not met, the weight of the counterweight beam (1) is increased by 10% of the original weight.

8. The earthquake-proof and disaster-reducing design method for a T-shaped rigid frame bridge according to any one of claims 1 to 7, characterized in that: In step S9, the optimization goal is to reduce the seismic deformation of the original bridge at the beam end of the T-shaped rigid frame bridge by more than 50%.

9. A construction method for a T-shaped rigid frame bridge, characterized in that: The following steps are involved: Construction of the T-shaped rigid frame bridge pedestal (4); A swing energy absorption and shock absorbing device is arranged on the support platform (4), and the swing energy absorption and shock absorbing device comprises a counterweight beam (1) and a plastic energy absorption rod (5). The top of the plastic energy absorption rod (5) is connected to the counterweight beam (1) and the bottom is connected to the support platform (4). The plastic energy absorption rod (5) is made of a solid soft metal rod.

10. A T-shaped rigid frame bridge, characterized in that: The design is performed by adopting the earthquake-resistant and disaster-reducing design method of a T-shaped rigid frame bridge as described in any one of claims 1 to 8, or the construction is performed by adopting the construction method of a T-shaped rigid frame bridge as described in claim 9.

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