What are the problems that need to be paid attention to in the arrangement of bridge bearings?

What are the problems that need to be paid attention to in the arrangement of bridge rubber bearings?(1) When the superstructure is a spatial structure, the bearing should be able to adapt to the deformation of the bridge in the direction of the bridge (in the X direction) and the transverse direction (in the direction of Y) at the same time(2) The bearing must be able to reliably transmit vertical and horizontal reaction forces;(3) The support should be so that the longitudinal displacement, transverse displacement and longitudinal and constant rotation angles caused by the deformation of the beam should be as unconstrained as possible;(4) The railway bridge usually has to be provided with a fixed bearing on each beam body;(5) When the bridge is located on the ramp, the fixed bearing should generally be located on the abutment in the downhill direction;(6) When the bridge is located on the flat slope, the fixed bearing should be located on the front end abutment of the main driving direction;(7) The fixed bearing should be arranged in the place with a large bearing reaction;(8) Several supports on the same pier should have similar rotational stiffness;(9) When the continuous beam may have a bearing subsidence, the possibility of making a height adjustment should be considered. In short, the principle of the arrangement of bridge bearings is not only to facilitate the transmission of support reactions, but also to make the supports fully adapt to the free deformation of the beam body.

1) First of all, according to the foreman of the construction site, the guardrail is set up for safety considerations, because the workers install the bridge bearing on the bridge pier, it is inevitable that this thing will fall to the ground, and the guardrail is set up to prevent people from walking in by mistake, so as to avoid some unnecessary incidents and play a safety role.

2) Secondly, it can be seen that workers wear work clothes and safety helmets when installing bridge bearings, which is for their own safety, and safety helmets are to protect personal heads from injury, because the installation of bridge bearings is high-altitude work, and it is inevitable that some unsatisfactory things will happen.

3) the third according to the introduction, this shoulder bag is called the tool bag, all the tools are placed in this shoulder bag when the bridge support is installed, in case of falling caused by safety accidents, and the employee can not rely on throwing to pass the tool, the required tools should be placed in the tool bag, so that the purpose of safe construction can be achieved.

Bridge bearings are important structural components that connect the bridge superstructure and the substructure. The bridge bearing is located between the bridge and the stepping stone, which can reliably transfer the load and deformation (displacement and turning angle) borne by the bridge superstructure to the bridge substructure, and is an important force transmission device of the bridge.

There are two kinds of fixed bearings and movable bearings. The commonly used bearing forms for bridge engineering include: linoleum or flat bearing, plate rubber bearing, spherical bearing, steel bearing and special bearing.

bridgesStructural classification

1. Beam bridges are generally built in places with large spans and shallow waters, which are composed of bridge columns and bridge plates, and the weight of objects is transmitted from the bridge plates to the bridge columns.

2. The arch bridge is generally built on the water area with a small span, the bridge body is arched, and there are generally several bridge holes, which play the function of flood discharge, and the weight in the middle of the bridge is transmitted to both ends of the bridge, and the weight at both ends is transmitted to the middle.

3. The suspension bridge is the most practical kind of bridge today, the bridge can be built in a place with a large span and water depth, composed of bridge columns, iron cables and bridge decks, the early suspension bridge can withstand the wind and rain, and will not be broken, and the suspension bridge can basically stand still when the storm comes.

It is an important force transmission device of the bridge to connect the bridge superstructure and the substructure, and reliably transmit the load and deformation (displacement and turning angle) borne by the bridge superstructure to the bridge substructure. There are two kinds of fixed bearings and movable bearings. Commonly used support forms for bridge engineering include:

Felt or flat bearings, plate rubber bearings, ball bearings, steel bearings and special bearings, etc.

(1) Transmit the supporting reaction force of the superstructure, including the vertical force and horizontal force caused by dead load and live load;

2) Ensure the self-deformation of the structure under the action of live load, temperature change, concrete shrinkage and creep and other factors, so that the actual force of the upper and lower structures conforms to the static schema of the structure.

Correct installation and regular maintenance are important measures to ensure the normal operation of bridge bearings.

When the bearing leaves the factory, it should generally be clearly marked, indicating the stationery model, reaction force and displacement, so as to avoid confusion during installation.

The support is usually transported to the construction site in whole after the factory is assembled, and in order to ensure the integrity of the Chinese seat during the transportation process, a temporary positioning device is used to connect the components of the support. These temporary positioning devices should be dismantled before the formal work of the bearing, and the specific time of dismantling should be determined by the engineering and technical personnel of the site according to the type of support and the structural stress state. For example, the upper and lower connecting plates of the movable support should be removed before the tension beam body is prestressed, so that the support can adapt to the deformation of the top stress of the beam body.

Before the installation of the bearing, the installation position of the bearing should be measured and inspected, and the mounting plane of the support should be parallel to the sliding plane or rolling plane of the bearing, and the deviation of its parallelism should not exceed 2.

Before the installation of the bearing, the relative position of the top and bottom plate of the movable bearing should be checked. The prefabricated displacement of the roller and sliding supports must meet the design requirements. When the preset displacement of the movable bearing must be adjusted due to the limitation of the installation temperature of the bearing, the adjustment of the displacement of the supporting seat should be carried out under the guidance of a professional engineer.

After the installation of the bearing, the rolling and sliding planes should be horizontal, and their inclination to the theoretical plane should not be greater than 2 o. In the center of the upper and lower plates of the bearing, its deviation is not more than 2%.

In order to ensure the smooth installation of the bearing, a dry and hard non-shrinkage mortar cushion with a thickness of 20-50 mm should be pounded between the bottom surface of the bearing and the supporting stone roof. The strength of the mortar cushion must be as strong as that of structural concrete. When the supporting plane is larger, the plastic mortar cushion can also be laid first, and the middle of the mortar layer is convex and spherical, and the mortar is flattened when the bearing seat is underneath.

If the support is leveled by measures such as screws or steel wedges during the installation of the bearing, the leveling screws and steel wedges must be removed after the pouring mortar cushion is solidified, so as to ensure that the mortar pad transmits force evenly. When installing the prefabricated beam, the self-weight of the beam body should be supported by the auxiliary structure first, and the weight of the beam body can be borne only after the supporting mortar solidifies and reaches the required strength.

When the designer designs the supporting stepping stone, it should be considered that there is a clearance of 30 cm between the bottom of the beam and the top surface of the pier, so that the use state of the bearing can be checked and maintained, and the dry jack can be placed if necessary to replace the stationery.

The bearing should be regularly maintained during its service life, including: the surface paint of the steel parts, the regular scrubbing and lubricating of the rotating part of the roller sleeve and the rotating part of the rocking shaft, the washing of the stainless steel surface of the sliding bearing and the inspection of the bearing money bolt, etc. Only regular maintenance can ensure the normal working condition of the bearing.

As an indispensable accessory for the normal operation of the bridge, the bridge bearing is an indispensable accessory, and below, Otelli will give you a science popularization about the installation steps of the bolted spherical bearing.

Bolted spherical support installation steps:

1) The top of the pier is chiseled and finished.

If the compensation shortening mortar is selected to fix the bearing, it is necessary to use an iron chisel to chisel the bearing surface of the bearing, and the degree of chiseling should be achieved"Concrete construction of bridges"For the relevant provisions of the construction joint treatment, and the top surface will be cleaned and cleaned. If the epoxy mortar is used to fix the bearing, the top surface needs to be cleaned and the bearing surface of the support needs to be kept dry.

2) Clean the reserved holes.

Before cleaning the reserved hole, check the orientation, size and depth of the anchor bolt hole at the top of the pier abutment, and then thoroughly sort it out after making sure that everything is qualified.

3) Manufacture of mortar.

Epoxy mortar should be configured in accordance with the proportion of relevant specifications, or the mortar should be compensated and shortened, and the strength should be not less than 35MPa.

4) Device anchor bolts and bearings.

After hoisting bearing is in place stably, the bearing bottom plate and the pier table surface support pad are leveled with a steel wedge at the four corners of the bearing, and the bottom surface of the bearing base plate should be higher than the pier abutment top 20mm 50mm, and then check the center line and elevation of the device.

5) Device template.

Along the side mold around the bearing, the scale of both sides of the template along the transverse axis of the pier should be greater than the width of the support by 100mm.

6) Pouring mortar.

Use epoxy mortar or compensating shrinkage mortar to fill the gap between the bolt hole and the bearing bottom plate and the pier table surface, and pour in from one end and flow out from the other end and exhaust when pouring to ensure that there is no hollowing phenomenon.

7) After determining that the mortar reaches the design strength, the four-corner steel wedge is withdrawn and the joints are filled with epoxy mortar.

8) Anchor bolts of the device support and the superstructure.

What are the key points that should be paid attention to when installing basin bridge bearings.

1. Arrange the reserved bolt holes. The anchor bolt is poured with the same number of concrete (or special mortar for bearing pouring) with the same number as the beam body, and attention should be paid to vibrating and compacting.

2. Before installing the bearing, the sliding joints should be carefully cleaned and kept clean, and special attention should be paid to the assembly of a complete set after filling the small pit of the PTFE plate.

3. It is necessary to align the longitudinal and horizontal parts on the bearing, and if the temperature is different from the planned temperature during installation, the spacing of the staggered components of the longitudinal support must be determined by calculation.

4. The nuts of the upper and lower plate bolts of the bearing should be fully installed and coated with butter without loosening.

5. The bearing and the bottom of the beam, the bearing and the supporting stepping stone should be closely attached and there is no gap.

6. Strictly control the fluidity and uniformity of the grout to ensure that the filling is compact.

I hope it can help friends in need to make the building safer!

(1) Before the installation of the bearing, the installation position of the support should be measured and inspected, and the mounting plane of the support should be parallel to the sliding plane or rolling plane of the support, and the deviation of the parallelism should not exceed 2.

2) Before the installation of the bearing, the relative position of the top and bottom plate of the movable bearing should be checked.

3) After the bearing is installed, the rolling and sliding planes should be horizontal, and the slope of its slope with the theoretical plane is not greater than 2. In the center of the upper and lower plates of the bearing, its deviation is not more than 2%.

4) In order to ensure the smooth installation of the bearing, generally between the bottom surface of the bearing and the top surface of the supporting pad stone, a dry and hard non-shrinkage mortar cushion with a thickness of 20 50mm should be pounded.

In order to ensure the construction quality of the bridge bearing, and the convenience of installing, adjusting, observing and replacing the bridge bearing, whether it is the cast-in-place beam method or the prefabricated beam method construction, no matter what type of bridge bearing is installed, it is necessary to set the support stepping stone at the top of the pier abutment.

The specific requirements are:

1) The quality of the goods should be strictly controlled when the bearing is purchased, and the bearing mixed with recycled rubber shall not be used.

2) To order a complete set of support products, and the steel plate of the exposed part of the support should be absolutely judged to be hot-dip galvanized according to the requirements.

3) When ordering the support, the manufacturer is required to promise that if quality problems are found during the bridge inspection before the opening of traffic and the completion inspection, it will be unconditionally replaced by the manufacturer.

4) The construction quality of the cushion stone of the bearing should be ensured, to ensure that the three degrees: height, flatness and levelness, special inspection should be carried out, and the on-site record and signature should be done, and it is strictly forbidden to level with mortar.

5) After the supporting device is in place (prefabricated hoisting and cast-in-situ device), a special inspection should be carried out, and the on-site record and signature should be made, and the file should be filed in triplicate for future inspection. Check the contents including: whether the support device has a pure deviation and skew scene; Whether there are bolts, steel plates or PTFE plates missing; Whether the direction of the device is wrong, etc.

1. Tie beam: Tie beam refers to the beam that plays the role of tie rod, mainly to connect two piles or piers into an overall force. Mainly refers to the transverse connection between two or more bridge piers, and the position between the piers is indefinite, and it may be the bottom, middle, or upper part, and is mostly arranged in the middle and lower parts.

As shown in the figure below (marked in red):

2. Cap beam: Cap beam refers to the cross beam set at the top of the row frame pile pier for supporting, distributing and transmitting the rubber combustion load of the superstructure. Also known as the hat beam. As shown in the figure below (marked in red):

3. Bridge bearing: The bridge bearing is an important structural component connecting the superstructure and the substructure of the bridge.

It not only has the role of force transmission, but also has the ability to transmit displacement and transform displacement, so that the bridge beam plate can move and vibrate within a controllable range. The position it is set up is above the sliding stone of the supporting pad beam, and below the bridge beam plate or box girder. As shown below:

4. Block: a block-shaped wall (generally connected with the cover beam) set up on both sides of the bridge deck in order to prevent the falling beam. For the most serious places, a stop is set between the beams to jam the beams to prevent lateral movement. As shown below:

5. Beam: The beam is mainly divided into box girder, beam plate, etc., which is a transverse structure that mainly carries the load of driving or pedestrians on the upper part of the bridge. As shown below:

6. Expansion joint: It is mainly a retractable device usually arranged between the two beam ends, between the beam end and the abutment or at the hinged position of the bridge in order to meet the longitudinal or transverse deformation requirements of the bridge beam plate and bridge deck. As shown below:

7. Cone slope: mainly to protect the embankment slope from erosion, the conical slope protection is built at the junction of the bridge culvert and the roadbed. As shown below:

The bridge bearing is arranged between the superstructure of the bridge and the pier abutment, and the various loads of the superstructure are transferred to the pier abutment, and can adapt to the displacement (displacement and rotation angle) generated by the load, temperature change, concrete shrinkage and other factors, so that the actual stress situation of the upper and lower structures conforms to the calculation schema of the design. The use effect of the bridge is closely related to whether the bearing can accurately play its function, so when the bearing is placed, the fulcrum position of the superstructure after the bridge is formed should be aligned with the center line of the support of the substructure.

With the passage of time of bridge opening and operation, various functional deterioration phenomena will occur in the bearing and stepping stones, and in order to maintain the long-term stability of the bearing performance, it is necessary to ensure the durability of the reasonable replacement. Here we can use the core bridge bearing products of Fortress Co., Ltd. to introduce:

Plate rubber bearing:

The bridge plate rubber bearing is made of multi-layer rubber sheet vulcanized and bonded with thin steel plate, which has enough vertical rigidity and can reliably transmit the reaction force of the superstructure to the pier abutment. It has good elasticity to adapt to the rotation of the beam end; It also has a large shear deformation capacity to meet the horizontal displacement of the superstructure.

Skateboard rubber bearings are suitable for large-span, multi-span continuous, simply supported beam continuous plate and other structures with large displacement. It can also be used as a slider in continuous beam jacking and T-beam traverse. The application of rectangular and circular slide rubber bearings is the same as that of rectangular and circular ordinary plate rubber bearings.

Spherical bearing: The vertical rotation angle of the spherical bearing is achieved by the sliding between the ball crown liner and the spherical slide. Because the center of rotation of the bearing does not coincide with the center of rotation of the upper part, a second sliding surface is formed between the upper support plate and the plane slide plate.

Depending on the relative position of the superstructure to the center of rotation of the support, the direction of rotation of the spherical surface can be consistent with or opposite to the direction of plane sliding.

It is particularly suitable for the construction of curves, wide bridges and inclined bridges on ramps, as well as large urban overpasses.

Basin bearing: basin rubber bearing is the use of elastic rubber body semi-enclosed in the steel pelvic cavity, which has the characteristics of fluid properties in the three-way stress state to realize the rotation of the superstructure; At the same time, the horizontal displacement of the superstructure is realized by relying on the low friction coefficient between the upper slide plate and the stainless steel plate.

It is suitable for large-span, multi-span continuous, simply supported beam continuous plate and other structures with large displacement bridges.

The bridge bearing design suggestion is to find a qualified company to provide professional technical solutions, and the targeted solutions for different bridge designs are more reliable. Founded in 2003, Fortress Intelligent Equipment Co., Ltd. is a professional service for major projects in key areas such as highways, railways, construction, water conservancy, electric power, rail transit, etc., specializing in providing bridge bearing products, and in 2021, Fortress officially joined hands with Keshun to provide customers with better products and services. There's a lot of relevant information below.