How to make bridge expansion joints? These on-site construction workers are already worried about losing their hair! _ Deck Full-time Job

The telescopic body can be in a compression state or a tension state. This is a kind of expansion device which is widely used in the construction of highway bridges in China at present. The common types are W, SW,custom tailor tape, M, PG and so on. This type of expansion device is suitable for bridge structures with expansion amount less than 80mm, that is, the joint width is 20mm-80mm. The main characteristics of this kind of expansion device are: ① simple structure, clear stress and low cost; ② the main components of the expansion device are processed by the manufacturer and installed on the construction site, and the connection with the beam end is generally welded by steel bars, so the structure is reliable and the construction quality is easy to guarantee; ③ good durability; ④ good waterproof and drainage performance; ⑤ good driving comfort. The two design principles of Mauler expansion joint are "rigid anchorage" and "sealing and waterproofing". 1) The anchorage of rigid anchorage expansion joint directly affects the service life of expansion joint. The anchoring metal plate mainly plays the role of force  complete waterproofing. At the same time, it can be replaced on the bridge deck or repaired by vulcanization with simple tools. Under the protection of the edge beam, the sealing strip is not directly rolled by the wheel, and its V-shaped structure can play a role in removing sediment by itself. The sealing strip can not only resist tension, but also carry out lateral and vertical displacement. In contrast, the leakage of expansion joints will cause some damage to the bridge structure. Steel bearing type The steel supported expansion joint is a structure assembled with steel, which can directly bear the wheel load. This kind of expansion device was used in steel bridges before, but now it is also used in concrete bridges. There are many kinds, current situation and sizes of steel supporting expansion devices, and the steel comb type is widely used. The structure of the steel comb-type bridge expansion device is composed of a comb-type plate, a connecting piece and an anchoring system. Some steel comb-type bridge expansion devices are filled with synthetic rubber between the combs to play a waterproof role, and some use special drainage grooves to solve the drainage problem. Steel comb-type bridge expansion device is also a finger-shaped joint of steel plate, which can be divided into supporting type and cantilever type according to the supporting condition of combs. The main features of this type of expansion device are: ① All components are processed and assembled by steel, with high structural strength; (2) continuous support can be provided for the wheels, and the driving comfort is good; ③ Embedded steel members shall be used for connection with the beam body, and the connection shall be reliable; (4) strong impact and vibration resistance and good durability; ⑤ It can adapt to large horizontal displacement and can be used for large bridges. This kind of expansion device is suitable for bridges with an expansion amount of more than 40 mm, but its application range is not very wide due to its high cost. Comb plate type expansion joint Rubber plate The rubber plate type expansion device makes full use of the characteristic of low shear modulus of the rubber material, a bearing steel plate and an anchoring steel plate are arranged in the rubber body, bolt holes are arranged, and the rubber plate type expansion device is connected with the beam end into a whole through bolts. This structure depends on the shear deformation of the rubber body between the upper and lower grooves to absorb the telescopic displacement of the beam, and the steel plate is embedded in the rubber body to span the gap between the beam ends and bear the wheel load. This kind of device was used earlier in China, and there are many manufacturers in the country with different names,garment measuring tape, mainly used in the 1980s and 1990s. The rubber plate type expansion device has the advantages of simple structure, convenient installation, economy, applicability and the like. It is mainly suitable for highway bridges below Grade II  has a certain buffer effect on the impact force of the wheel, effectively protects the expansion device and the beam body, and improves the driving conditions. ③ The angle steel of the expansion device effectively strengthens the end strength of the cial-shaped steel directly bears the wheel oss beam, control transmission mechanism, displacement box, sealing rubber strip and other components, and the structure is complex; ② The sealing performance is good, and the waterproof and drainage performance is good; der the change of material thermal properties. For the bridge with small span (L ≤ 8m), the linear expansion coefficient is very small, so it can be ignored; for the bridge with large span, enough attention must be paid in the design. For general design, the linear expansion coefficient can be calculated according to the following table Temperature variation range and linear expansion coefficient 2. Shrinkage and creep of concrete Shrinkage and creep of concrete are the inherent properties of concrete components, and also a random phenomenon. Concrete's mix proportion, water-cement ratio, slump, retractable tape measure sewing ,personalised tailor tape, cement variety, temperature, relative humidity, concrete's loading age, load holding time and strength have great influence on concrete's shrinkage and creep. Shrinkage and creep shall be considered for both reinforced and prestressed  part of the bottom V-shaped rubber strip shall also be blocked by polyethylene foam board to prevent mortar leakage. Top flatness control Copyright statement: The source of this WeChat content is Zhulong Forum. Copyright belongs to the original author, if it involves copyright issues,bra measuring tape, please contact us, we will be the first time to negotiate copyright issues or delete the content! 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