A T-shaped rigid frame bridge seismic disaster reduction design method and construction method

Abstract

The present invention relates to the technical field of disaster prevention and mitigation, and is a design method and a construction method for earthquake prevention and disaster reduction of a T-shaped rigid frame bridge. The design method adds a swing energy dissipation and shock absorption device during the design process of the T-shaped rigid frame bridge and performs coordinated optimization, so that the T-shaped rigid frame bridge does 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 and the abutment to the bridge piers and main beams, reduces the earthquake force on the bridge piers, reduces the displacement and slapping effect of the main beam, and protects the operational safety of the T-shaped rigid frame bridge.

Description

Technical Field

[0001] The present 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 undergo 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" against the abutments, and the impact force on the main beams during the beating process will be relatively large. In severe cases, the main beams will crack or collapse.

[0003] Domestic and foreign scholars have conducted extensive 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 withstand seismic forces under earthquakes. Damage to the piers causes energy consumption and destruction. Once the piers of a T-shaped rigid frame bridge undergo plastic failure under earthquakes, the main beam will undergo large displacement, making it difficult to repair and reposition the damaged piers.

[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 forces of the pier structure under 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 stresses 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 easily put into a plastic state, swinging violently and suffering 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. Although this has improved the flexural and shear bearing capacity of the piers, the increased stiffness of the piers has also increased the seismic force on the piers and the foundation, making 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 slapping of the abutments, and the above-mentioned shock-absorbing and energy-consuming measures are directional, they cannot solve the problems of the three-dimensional spatial deformation and slapping effect of the T-shaped rigid frame bridge piers during earthquakes.

[0008] Therefore, in order to ensure the seismic performance of T-shaped rigid frame bridges, reduce the risk of earthquake 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 construction method for a T-shaped rigid frame bridge, in view of the existing problem of pier-beam consolidation of T-shaped rigid frame bridges 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, they are difficult to repair and reset. At the same time, the main beam will undergo 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. Install a swing energy dissipation and shock absorption device around the top of the pier of the T-shaped rigid frame bridge. The swing energy dissipation and shock absorption device includes a counterweight beam and a plastic energy dissipation rod. The top of the plastic energy dissipation rod is connected to the counterweight beam and the bottom is connected to the pier. The plastic energy dissipation 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. Assume that the yield displacement design value of the plastic energy-absorbing rod under the initial value of 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 moment of inertia;

[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 pier, the elastic stiffness of the swing energy dissipation and shock absorption device, and a 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 of the natural vibration period of the structure t(1);

[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 structure's natural vibration period 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 dissipation rod are solved through the response spectrum curve, where i=1, 2, 3...;

[0019] S5. Based on the earthquake force Fz(i) borne by the bridge and the bridge seismic design specifications, 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 of each bridge component, and update the M2, M3 and K2, K3 values ​​accordingly, and repeat step S3;

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

[0022] S6. Substituting the new elastic stiffness value K(i) of the plastic energy dissipation rod and the updated values ​​of M2, M3, K2, and K3 into step S3, and 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. Using the response spectrum curve, the seismic force Fz(i+1) of the bridge and the seismic force F(i+1) of the plastic energy dissipation rod are obtained;

[0023] S7. Error in earthquake 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. Adjust the obtained seismic force F(i+1) of the plastic energy dissipation rod downward by 20%-30% as the design yield load to obtain the yield load of each plastic energy dissipation rod, solve the yield displacement of the plastic energy dissipation rod, and re-obtain the elastic stiffness K(i+1)×n of the swing energy dissipation and shock absorption device, thereby completing the design of the swing energy dissipation and shock absorption device and the design of the bridge pier cross section.

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

[0027] When the seismic displacement of the beam end fails to meet the design target, the mass M1 of the counterweight beam is increased in increments of the 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 earthquake energy, reduces the transmission of earthquake energy from the foundation and the abutment to the bridge piers and main beams, reduces the earthquake force on the bridge 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 bridge piers.

[0029] As a preferred technical solution of the present invention, in step S1, the swing energy dissipation and shock absorption device further 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 plays a role, 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 mild steel rod or a hollow mild 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 method for constructing a T-shaped rigid frame bridge, comprising the following steps:

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

[0038] A swing energy dissipation and shock absorption device is provided on the supporting platform, and the swing energy dissipation and shock absorption device includes a counterweight beam and a plastic energy dissipation rod. The top of the plastic energy dissipation rod is connected to the counterweight beam, and the bottom is connected to the supporting platform. The plastic energy dissipation 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-reduction 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 provides a method for earthquake-proof and disaster-reduction design of a T-shaped rigid frame bridge. By adding a swing energy dissipation and shock absorption device to 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 and abutment to the bridge piers and main beams, reduces the earthquake force on the bridge 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 bridge piers. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0043] Figure 2 Schematic diagram of the structure of a swing energy dissipation and vibration reduction device for a T-shaped rigid frame bridge;

[0044] Figure 3 It is a structural 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 zones;

[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-bridge pier, 4-cap, 5-plastic energy dissipation rod, 6-transverse connector, 7-anti-collision elastic member, 8-foundation, 9-anchor, 10-base plate, 11-first bolt, 12-second bolt, 13-top base plate. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be understood as limiting the scope of the present invention to the following embodiments, and all technologies implemented based on the present invention fall within 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 positional relationship, such as "upper", "lower", "left", "right", "center", "inside", and "outside", are based on the expressions of the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the invented product / device / apparatus is placed when it is conventionally used. These terms of orientation or positional relationship are merely for the purpose of facilitating the description of the scheme of the present invention or simplifying the description of the specific embodiments to facilitate the rapid understanding of the scheme by technicians, 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 positional relationship, and therefore should not be understood as limiting 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 simply understood that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", and "parallel", 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 solution of the present invention.

[0052] In addition, the expressions “first”, “second”, “third”, etc. 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 two. It can also be any number such as two, three, four, five, six, seven, eight, nine, or even more than nine.

[0054] Furthermore, in the description of the technical solution of the present invention, unless otherwise expressly specified, defined, or limited, the terms "disposed," "installed," "connected," "connected," "provided with," "laid," and "arranged" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections. They may be welded, riveted, bolted, threaded, or other commonly used connection methods in the art. Such connections may be mechanical, electrical, or communicative; they may be direct, indirect via an intermediate medium, or internally connected between two components.

[0055] In the related art, the piers and beams of T-shaped rigid frame bridges are consolidated. Under earthquake action, the piers are mainly used to bear the earthquake force. Once the piers of a T-shaped rigid frame bridge are plastically damaged under earthquake action, it is difficult to repair and restore them. At the same time, it will cause the main beam to undergo large displacement, resulting in an unfavorable state where the main beam end hits the abutment. For this reason, the technical solution of this application was developed. Figures 1 to 6 To elaborate.

[0056] Example 1

[0057] like Figures 1 to 6 As shown, the earthquake-proof and disaster-reduction design method of a T-shaped rigid frame bridge according to 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. The device includes a counterweight beam 1, a plastic energy absorption component, a transverse connection component 6, and an anti-collision elastic component 7. 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. The plastic energy absorption rod 5 is a soft metal rod, such as a solid soft steel rod or a hollow soft steel pipe.

[0059] In some optional embodiments, 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 plate 13. The plastic energy dissipation rod 5 is connected to the base 4 via the base plate 10, and the plastic energy dissipation rod 5 is connected to the counterweight beam 1 via the top plate 13. Specifically, an anchor 9 is provided in the base 4, the base plate 10 is connected to the anchor 9 via a first bolt 11, and the top plate 13 is connected to the counterweight beam 1 via a second bolt 12.

[0061] In some optional embodiments, the counterweight beam 1 is configured as a rectangular frame, surrounding the pier 3 of a T-shaped rigid frame bridge. Several anti-collision elastic members 7 are connected to the inner side of the counterweight beam 1, with spacing between the anti-collision elastic members 7 and the outer wall of the pier 3. Specifically, the four sections of the rectangular counterweight beam 1 can be connected by welding or bolting; the anti-collision elastic members 7 can be springs (with a pad provided on the end facing the pier 3), rubber pads, or both; and each section of the rectangular counterweight beam 1 is equipped 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 by at least one transverse connecting member 6 .

[0063] In some optional embodiments, the pier 3 of the T-shaped rigid frame bridge adopts a solid pier in the part where the swing energy dissipation and shock absorption device is provided, and the part above it can adopt 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 stiffness of the pier 3 is K3, the stiffness of the foundation 8 is K4, and the side span connection stiffness is K5.

[0065] Assume that the natural vibration period corresponding to the initial elastic stiffness is within the design response spectrum of the earthquake zone (e.g. Figure 5 The platform section of the curve shown in the figure is used to calculate the initial value of the seismic 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, M1 is the initial mass of the counterweight beam 1, and is generally taken as 1 / 120 to 1 / 100 of the weight of the pier 3.

[0066] Step 2: In the elastic working stage, the yield displacement design value 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 dissipation rod 5, where n is the number of plastic energy dissipation rods 5, H is the height of the plastic energy dissipation rod 5, E is the elastic modulus, and I is the section moment of inertia.

[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 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 TIt is designed to be an integer multiple of K(1), for example, K(1)×10 times.

[0068] Step 3: Based on the deadweight and stiffness of the main beam 2 and 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 structural natural vibration period 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 earthquake 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 of the key bridge components until they are met. At this point, the cross-sectional dimensions and mass of the key bridge components have changed, and the M2, M3, K2, and K3 values ​​need to be updated accordingly, and step 3 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 dissipation rod 5 and the updated M2, M3 and K2, K3 values ​​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 dissipation rod 5 are obtained.

[0074] Step 7. Error in seismic force borne by the bridge ε is a 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: Reduce the obtained seismic force F(i+1) of the plastic energy dissipation rod 5 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, and 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 part 7 and the bridge pier 3, complete the design of the swing energy dissipation and shock absorption device and the design of the cross section of the bridge pier 3.

[0077] Step 9. Establish the constitutive model of the entire bridge and the swing energy dissipation and shock absorption device (the T-shaped rigid frame bridge adopts a three-dimensional beam unit model, considering the nonlinear model of the side span support, 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 conducted (calculating the results of three rare earthquakes and taking the average value for analysis). The difference between the deformation value D1 of the side span support of the T-shaped rigid frame after the installation of the swing energy dissipation and shock absorption device 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 absorption 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 then completed, the seismic design of the T-shaped rigid frame bridge is realized, and the slapping effect problem is solved.

[0080] T-shaped rigid frame bridges are generally built in high mountain canyons. The bridge piers 3 are very high and rocks are easily fallen from the mountains on both sides of the canyon. 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-proof and disaster-reduction design of a T-shaped rigid frame bridge. By adding a swing energy-absorbing and shock-absorbing device to 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-absorbing and shock-absorbing device dissipates earthquake energy, reducing the transmission of earthquake energy from the foundation 8 and the pedestal 4 to the pier 3 and the main beam 2, thereby reducing the earthquake force on the pier 3, reducing the displacement and slapping effect of the main beam 2, and protecting the operational safety of the T-shaped rigid frame bridge. At the same time, the swing energy-absorbing and shock-absorbing 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-embedded anchors 9 are used. The anchors 9 can be U-shaped anchor bars with threaded sleeves connected to the ends of the U-shaped anchor bars. The anchors 9 serve as the basis for installing the swing energy dissipation and shock absorption device. After the construction of the bridge pier 3 is completed, the swing energy dissipation and shock absorption device can be installed.

[0086] A2. Install the plastic energy absorbing component. The plastic energy absorbing component includes several 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. Install the plastic energy absorbing rods 5 one by one and connect the base plate 10 to the anchor 9 through the first bolt 11.

[0087] A3. Install the transverse connector 6. Connect the transverse connector 6 and the plastic energy dissipation rod 5 by welding, so as to connect the plastic energy dissipation components together to form a whole.

[0088] A4. Use a truck crane to hoist four counterweight beams 1 (the counterweight beams 1 have a solid steel section with counterweight blocks filled in the hollow section) one by one onto the top of the plastic energy dissipation component. Connect them to the top base plate 13 of the plastic energy dissipation component using second bolts 12. Then, each counterweight beam 1 hoisted up is welded to the counterweight beam 1 that has already been hoisted up, forming a rectangular frame of counterweight beams 1.

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

[0090] Example 3

[0091] like Figures 2 to 4 As shown, the 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 scope of protection of the present invention.

Claims

1. A design method for earthquake-proof and disaster-reduction of a T-shaped rigid frame bridge, characterized in that: The following steps are involved: S1. A swing energy dissipation and shock absorption device is provided around the top of the pedestal (4) of the T-shaped rigid frame bridge. The swing energy dissipation and shock absorption device comprises a counterweight beam (1) and a plastic energy dissipation rod (5). The top of the plastic energy dissipation rod (5) is connected to the counterweight beam (1) and the bottom is connected to the pedestal (4). The plastic energy dissipation 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 is obtained as 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 dissipation 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 the initial value K(1) of the elastic stiffness value K(i) of the plastic energy dissipation rod (5), where n is the number of the plastic energy dissipation rods (5), H is the height of the plastic energy dissipation rod (5), E is the elastic modulus, and I is the section inertia moment; According to K (1), the specific structure of the plastic energy dissipation rod (5) is optimized and designed; S3. Based on the deadweight and stiffness of the main beam (2) and the pier (3), the elastic stiffness value of the swing energy dissipation and shock absorption device, and a 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 natural vibration period of the structure; 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 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 dissipation rod (5) are solved, where i=1, 2, 3...; S5. Based on 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 of each bridge component, and update the M2, M3 and K2, K3 values ​​accordingly, and repeat step S3; If the requirements are met, the yield displacement of the plastic energy dissipation rod (5) under the action of the earthquake force F(i) is solved, and the elastic stiffness value K(i) of the plastic energy dissipation rod (5) is solved; S6, the elastic stiffness value K(i) of the new plastic energy dissipation rod (5), and the updated values ​​of M2, M3 and K2, K3 are substituted into step S3, and the characteristic value of the T-shaped rigid frame bridge is solved by the finite element method to obtain the natural vibration period t(i+1) of the bridge structure, and the seismic force Fz(i+1) of the bridge and the seismic force F(i+1) of the plastic energy dissipation rod (5) are obtained through the response spectrum curve; S7, bridge borne earthquake force error 0< <ε, 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 dissipation rod (5) by 20%-30% as the design yield load, obtaining the yield load of each plastic energy dissipation rod (5), solving the yield displacement of the plastic energy dissipation rod (5), and re-obtaining the elastic stiffness K(i+1)×n of the swing energy dissipation and shock absorption device, thereby completing the design of the swing energy dissipation and shock absorption 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 entire 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 earthquake displacement of the beam end fails to reach the design target, the mass M1 of the counterweight beam (1) is increased in increments of 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 swing energy dissipation and shock absorption device further includes an anti-collision elastic member (7), 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 is 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-reduction 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 T-shaped rigid frame bridge is designed using the earthquake-resistant and disaster-reduction design method for a T-shaped rigid frame bridge according to any one of claims 1 to 8. The construction method comprises the following steps: Construction of the T-shaped rigid frame bridge pier (4); A swing energy dissipation and shock absorption device is provided on the support platform (4), and the swing energy dissipation and shock absorption device comprises a counterweight beam (1) and a plastic energy dissipation rod (5). The top of the plastic energy dissipation rod (5) is connected to the counterweight beam (1) and the bottom is connected to the support platform (4). The plastic energy dissipation rod (5) is a solid soft metal rod.

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

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