CN116065479A - A railway self-resetting bridge pier with external SMA energy dissipation device - Google Patents

Abstract

The invention discloses a railway self-resetting pier with an external SMA (shape memory alloy) energy consumption device, which relates to the technical field of bridge structure vibration reduction and isolation. And the abutment is designed separately, and the bottom surface of the adding table and the surface of the pile foundation bearing platform are wrapped by steel plates. The SMA energy consumption device consists of an SMA wire bundle, an embedded steel bar and an anchor, wherein the SMA wire bundle penetrates through the flange of the adding table, one end of the SMA wire bundle is anchored on the flange of the adding table by the anchor, and the other end of the SMA wire bundle is connected with the embedded steel bar. The railway self-resetting pier with the external SMA energy consumption device can realize self-resetting by utilizing the super-elastic effect of the SMA self-assisting pier after earthquake, and can lift the pier away from the earthquake in earthquake to isolate earthquake, and the SMA energy consumption device dissipates earthquake energy, so that the pier is free from plastic hinge damage, the earthquake resistance of a bridge structure is effectively improved, and the earthquake resistance target of protecting the pier main body and the foundation is achieved. The SMA energy consumption device is easy to replace after being damaged, and the pier can quickly recover the normal use function after replacement, so that the operation and maintenance cost can be greatly reduced, and the method has good social comprehensive benefits.

Description

A railway self-resetting bridge pier with external SMA energy dissipation device

technical field

The invention belongs to the technical field of vibration reduction and isolation of bridge structures, and in particular relates to a railway self-resetting bridge pier with an external SMA energy dissipation device.

Background technique

Although the ductile design can prevent the bridge from collapsing in strong earthquakes, its plastic deformation ability also leads to irreversible damage to the structure, making it extremely difficult to repair. In recent years, more and more experts and scholars have devoted themselves to exploring and researching performance-based anti-seismic design concepts such as base sway isolation and energy dissipation shock absorption. The response under the earthquake reduces the damage caused by the earthquake to the structure. The base sway isolation system is to lift the pier away from the sway and isolate the huge energy released by the earthquake so as to protect the main body of the pier. The use of this performance-based seismic design idea can effectively reduce the damage to the structure caused by the earthquake, save a huge amount of repair funds, and ensure the safety of people's lives and properties.

Installing energy-dissipating shock-absorbing devices in base-swaying seismic-isolation piers with self-resetting characteristics is one of the applications of performance-based seismic design ideas. Patent application CN109972501A discloses a new type of swinging self-resetting bridge pier with energy dissipation device and its application. Low yield point mild steel stretches and high damping rubber compresses and deforms to dissipate earthquake energy. However, due to the particularity of rubber materials, its performance is greatly affected by factors such as temperature, durability, and strain amplitude. It needs to be replaced regularly to ensure the normal use of the bridge. Require. Patent application CN108729344A discloses a double-column bridge pier structure combined with vibration isolation. The invention is to arrange roller vibration isolation bearings at the bottom of the upper cap to play a vibration isolation effect on the swing bridge, and connect the pier body through an angle steel damping device. The function of dissipating the seismic energy is realized by using the bearing platform, but this energy-dissipating device yields when dissipating the seismic energy, the energy-dissipating capacity is limited, and the structure still produces residual deformation. Patent application CN103362063A discloses a base swing shock isolation device for pile foundation piers. The invention is to implant prestressed anti-overturning steel strands or steel bars in the pier body to limit and dissipate energy. The ribs are not conducive to the stability of the pier, and the prestress will cause stress relaxation loss, and the effect of shock absorption and energy dissipation is not obvious. SMA (shape memory alloy) has the advantages of superelastic effect, shape memory effect, high damping performance, fatigue resistance, corrosion resistance, high durability, etc. It is an ideal shock-absorbing and energy-consuming material, and is widely used in civil engineering self-resetting The field of energy-consuming devices. In view of this, the present invention discloses a railway self-resetting bridge pier with an external SMA energy dissipation device, which utilizes an external SMA tow to dissipate hysteretic energy and play a reset role to realize recoverable functions after an earthquake.

Contents of the invention

The purpose of the present invention is to provide a railway self-resetting bridge pier with an external SMA energy-dissipating device, which is intended to solve the problems of unstable energy consumption, large residual displacement, weak reset ability, and poor aging durability of the device in self-resetting bridge piers with energy-dissipating devices. difficulties etc.

The purpose of the present invention is achieved like this:

A railway self-resetting bridge pier with an external SMA energy-dissipating device mainly includes a pier column, an abutment, a pile foundation cap, a steel plate, a separation surface, and an SMA energy-dissipating device. The pier column and the added platform are bonded into a whole, and the pier and abutment are designed separately, and there is a separation surface between the added platform and the pile foundation cap. The added platform is similar to the box-section design, and its top flange is used for the installation of energy dissipation devices, and through holes are reserved in the flange. Both the bottom section of the abutment and the upper surface of the pile foundation cap are wrapped with steel plates to prevent the concrete from being crushed during lifting and swinging. The SMA energy dissipation device is located between the added platform and the pile foundation cap, and is mainly composed of threaded steel rods, nuts, bolt sleeves, steel pads and SMA wire bundles, among which, the SMA wire bundles (3) are composed of CuAlBe shape memory alloy wire combined. The threaded steel rod is pre-buried in the pile foundation cap, and the end protrudes a certain length to connect with the SMA wire bundle. The embedded part is provided with a hook section. The SMA wire bundle passes through the through hole reserved on the flange of the platform, and the lower end passes through the nut. The bolt sleeve is connected with the SMA tow by anchoring, and the upper end is anchored on the platform by pads and nuts.

Advantage of the present invention and beneficial effect are embodied in:

1. Under normal use, the bridge pier basically remains static under the joint action of the mass of the bridge span, the self-weight of the bridge pier and the vertical force provided by the energy-dissipating device, which meets the daily driving requirements.

2. Due to the separate design of the piers and abutments, when an earthquake occurs, the bottom of the pier is lifted to isolate the earthquake, effectively dissipate the seismic energy, reduce the seismic response of the pier, and avoid plastic hinge damage in the pier. After lifting off the bottom of the platform, the seismic action will be greatly reduced, which will help the seismic design of the foundation.

3. Installing SMA energy-dissipating devices between the abutment and the pile foundation cap can increase the horizontal stiffness of the pier, limit the lift-off displacement, and improve the performance of the pier. During the rocking lift-off process, the SMA tow uses its own superelastic effect and high damping performance to consume hysteretic energy in the reciprocating stretching, and concentrates the seismic loss on the SMA energy dissipation device, reducing the damage of the earthquake to the pier body, maximizing The safety of the bridge structure is guaranteed to a certain extent. The SMA energy dissipation device is connected by bolt anchorage, and it is easy and convenient to replace after damage.

4. The energy-dissipating device can also use the superelastic effect of SMA tow to make the bridge pier have stronger reset ability and superior overall deformation ability, which can play a role in controlling the residual deformation of the bridge pier. It has no damage after the earthquake and self-recovery function At the same time, it also acts as a limiter to prevent the pier from overturning in rare earthquakes.

5. The steel plate wrapped on the contact surface of the added platform and the pile foundation cap can be used as a construction template to simplify the construction procedure, and in the effect of rocking collision, it can prevent the concrete around the support point from being crushed.

6. The present invention has the advantages of stable energy consumption, superior self-resetting ability, no damage after an earthquake, and recoverable functions, etc., and the seismic performance of the pier can be significantly improved with a slight modification to the existing conventional self-resetting pier, and has a wide range of applications . After the earthquake, the pier reset itself, which ensured the smooth traffic of the disaster relief transportation line and won precious time for the rescue and relief work. The external SMA tow is very easy to replace. By replacing the SMA tow after the earthquake, the pier can be quickly restored to the original function level, which can save a huge amount of repair funds, has good social comprehensive benefits, and is worthy of popularization and use in actual projects.

Description of drawings

Accompanying drawing 1 is the schematic diagram of the adhesion stage of the present invention.

Accompanying drawing 2 is the schematic diagram of the rocking stage of the present invention.

Accompanying drawing 3 is the partially enlarged schematic diagram of accompanying drawing 1.

Accompanying drawing 4 is the structural diagram of SMA energy dissipation device in the present invention.

The names and corresponding numbers of each part in the diagram: pier column 1, abutment 2, SMA tow 3, steel plate 4, pile foundation cap 5, separation surface 6, nut 7, steel pad 8, bolt sleeve 9, embedded Threaded steel rod 10.

Detailed ways

Below in conjunction with accompanying drawing, describe in detail the embodiment of the present invention:

Based on the existing conventional reinforced concrete pier foundation, the present invention connects the pier-abutment separation design through the SMA energy dissipation device, makes full use of the lift-off swing vibration isolation energy consumption and realizes the self-resetting function, and ensures that the main body of the pier will not be damaged under earthquake excitation , to achieve the purpose of shock absorption and energy consumption. The structure is mainly used in the technical field of shock absorption and isolation for railway bridges.

As shown in Figure 1 and Figure 2, the present invention is a railway self-resetting bridge pier with an external SMA energy dissipation device, including beams, pier columns, added platforms, bearings, pile foundation caps and pile foundations, pile foundation caps The lower part is connected to the pile foundation, and the bottom of the pier column is bonded and connected with the abutment to be placed on the pile foundation cap as a whole. It is connected through four external SMA energy dissipation devices. The pier top is placed with a support, and the beam is erected on the support. In daily use, the bridge pier is in the adhesion stage shown in Figure 1, and the mass of the superstructure, its own weight and the vertical force provided by the SMA energy dissipation device are fully used to balance the wind load, train braking force and frequent earthquakes. When a sudden and rare earthquake occurs, the pier will sway as shown in Figure 2, thereby playing the role of sway isolation, and during the sway process, the SMA energy dissipation device can achieve the purpose of shock absorption and energy consumption.

As shown in Figure 3, the added platform is similar to the box-section design, and the overhanging flange on the top is used for the installation of SMA energy dissipation devices. During construction and pouring, through holes are reserved at the four corners of the added platform flange. The added platform and the pile foundation cap are in contact with the surrounding steel plate to avoid concrete crushing during the swing.

As shown in Figure 4, the external SMA energy dissipation device is composed of threaded steel rods, nuts, steel pads, bolt sleeves and SMA wire bundles. When pouring the pile foundation cap, the threaded steel rod is pre-embedded in the pile foundation cap, the end of which is extended to a certain length, and the pre-embedded part is provided with a hook and thread, which can enhance the occlusal effect with the concrete. The SMA wire bundle passes through the through hole reserved on the flange of the mounting platform, the lower part is connected with the SMA wire bundle through a bolt sleeve, and the upper part is anchored on the mounting table with steel pads and nuts, and the SMA wire bundle is made of a CuAlBe shape with a wider working temperature. Combination of memory alloy wire. The device mainly uses SMA tow stretching and restoring hysteretic energy consumption, and can play a reset role, helping the pier to self-reset and avoid overturning and collapsing at the epicenter.

The invention can not only meet the requirements of normal driving, but also has the advantages of almost no damage after the earthquake, small residual displacement, strong energy dissipation capacity, self-recovery structure, etc., and the replacement of SMA tow is simple and convenient, and the bridge pier can quickly restore the normal function after replacement. The comprehensive social benefit is greatly improved, and it can be popularized and used in practical projects.

This specification describes the principle and implementation of the present invention in detail. It should be understood that the above description does not limit it to the specific structure and scope of application, so any corresponding modifications and equivalents that may be used, All belong to the protection scope of the present invention.

Claims (4)

1. The utility model provides a railway self-resetting pier of external SMA power consumption device, includes pier stud (1), adds platform (2), steel sheet (4), stake basic cap (5), separation face (6) and SMA power consumption device, its characterized in that: pier stud (1) with add platform (2) bond into wholly, add platform (2) with pile foundation cushion cap (5) are for unbonded connection, exist between separation face (6), SMA power consumption device is arranged in outward add platform (3) with between pile foundation cushion cap (5).

2. The railway self-resetting pier of the external SMA energy consuming device of claim 1, wherein: the adding table (2) is similar to a box-shaped section design, the top overhanging flange is convenient for anchoring and mounting the SMA energy consumption device, and a through hole is reserved in the flange of the adding table (2).

3. The railway self-resetting pier of the external SMA energy consuming device of claim 1, wherein: the contact surface of the adding table (2) and the pile foundation bearing table (5) is wrapped by a steel plate (4).

4. The railway self-resetting pier of the external SMA energy consuming device of claim 1, wherein: the SMA energy consumption device is composed of a nut (7), a steel cushion block (8), an SMA wire bundle (3), a bolt sleeve (9) and a threaded steel rod (10), wherein the threaded steel rod (10) is embedded in a pile foundation bearing platform (5), the end part of the threaded steel rod extends outwards to a certain length and is connected with the SMA wire bundle (3), a hook section is arranged at the embedded part, the SMA wire bundle penetrates through a reserved through hole of a flange of the adding platform (2), the lower end of the SMA wire bundle is connected with the threaded steel rod (10) through the nut (7) and the bolt sleeve (9), the upper end of the SMA wire bundle is anchored on the flange of the adding platform (2) through the nut (7) and the steel cushion block (8), and the SMA wire bundle (3) is formed by combining CuAlBe shape memory alloy wires with wider working temperatures.

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