Bridge expansion joints Bump issue is currently on the road of common diseases highway, and with the development of roads, the problem has become increasingly prominent. Therefore, to analyze the reasons for the bridge expansion joints jumping generated, then put forward the principle of prevention and maintenance becomes necessary. Telescopic device of the type of bridge expansion joints used in road construction at present many types, a common plate rubber joints, teeth mouth steel joints, SD-80-type expansion joints, XT-80 wool Expansion Joints, XF-160 Maurer joints, and TST elastomer and gravel-filled telescopic devices. Plate telescopic device is the most used and most extensive telescopic device, basically applicable on medium span bridges. Maurer steel expansion joint device is suitable for all medium and large bridges. In recent years there TST elastomer and gravel-filled telescopic device widely used for small displacement of the small and medium-span bridges. Several more forms telescopic device structure, reasonable, applicability have their own characteristics, but the incidence of disease is also a lot of damage to the phenomenon, there are still some problems. Bridge expansion joint device causes of damage as a result of the bridge expansion joint device settings in the weak end of the beam structure of the site, the direct effect of the vehicle to withstand repeated loads, so telescopic device is fragile and difficult to repair the site. Telescopic device breakage reasons are many, are: ill-designed bridge expansion joints when the beam end design failed to consider carefully, in the repeated loads, damage caused by the beam end telescopic device malfunction, the other, and sometimes do not calculate the amount of deformation appropriate, using a too large stretching distance, leading to telescopic device breakage. Bridge expansion joint problem telescopic device itself telescopic device itself insufficient stiffness of the structure, the strength of the anchor component shortage, resulting in varying degrees of damage in the operation process. After the bridge expansion joint expansion joint filler material inappropriate choice of pouring pressure telescopic device after pouring pressure filling material is not taken seriously, carefully selected, resulting in lower quality telescopic device operating, resulting in varying degrees of disease. Improper construction process, the construction of which bridge expansion joints, expansion joints end of the beam according to the design requirements for the completion of the pitch did not artificially zoom in and out, positioning angle position is incorrect, resulting in telescopic device does not work. Telescopic device anchoring steel construction is not strong enough or produce the phenomenon of embedded anchor bars disease left to itself, causing joints hidden. Construction expansion joint device installed well, bad joints after pouring bridge deck, causing damage to the joints under cyclic loads. Bridge expansion joints bridge expansion joints are generally classified butt, steel bearing type, a combination of shear (plate), and the elastic modulus of the supporting device type. Butt butt joints devices, depending on their structure and mechanical characteristics of the form can be divided into packing and embedded solid butt butt type two. Padded butt type telescopic device is asphalt, wood, oakum, rubber and other materials filling the gap, stretching the body in any case are in compression. Such telescopic device is generally used in the amount of stretching conventional 40mm below the bridge project, it has been rare. Embedded solid docking expansion joint device using different forms of steel members will be different shapes rubber strip (band) embedded firmly fixed, and the rubber strip (with) the tensile and compressive deformation to absorb deformation of the beam, which can be in the body by stretching pressure state. Also in tension. Modulus of deformation of the support when the retractable bridge over 50mm, often with steel telescopic device. The telescopic device when the vehicle is often due to the end of the beam passing through the rotation or deflection produced slap effect, noise, and easy to make structural damage. Therefore, the device has a bolt requires the use of a spring to fix the slide plate to reduce the rattling and noise, the joints of the structure is relatively complex. The shearing device is using a variety of different cross-sectional shape of the rubber band as a caulking material telescopic device. The rubber elastic, easy to paste, but also to meet the requirements and have waterproof deformation. Bridge expansion joints in domestic and foreign bridge engineering has been widely used. Steel backing plate rubber products in this category telescopic device, it is difficult to meet the requirements of a large amount of displacement; steel type of telescopic device, it is difficult to achieve watertight seal, and easy to impact on the vehicle, the impact of travel of the vehicle. Therefore, there has been a good performance and easy to use shock-absorbing cushion rubber sealing material to do with the strength of good performance shaped steel combination, in the case of a large amount of displacement of the vehicle can withstand the load-supporting several types of mold (Modular ) bridge expansion series. Elastomer elastomer telescopic device into zinc metal joints and TST gravel elastic joints, elastomer telescopic device is a simple expansion joint device for small and medium-span bridges, when the amount of stretching can within the 20mm-40mm TST gravel using elastic expansion joint device, a special elastic-plastic material is heated to melt TST, poured through the rubble cleaning heating, namely the formation of elastic joints TST gravel, gravel to support the vehicle load, TST elastic-plastic body at a 25 ℃ ~ 60 ℃ conditions to meet the requirements of the amount of stretch. Type expansion joints in accordance with the performance and installation methods can be divided into: GQF-C type, GQF-Z type, GQF-L type, GQF-F type. Which GQF-MZL number of model type bridge expansion joint device is the use of hot-rolled shaped steel bridge expansion joint device overall shape of the design. GQF-C type, GQF-Z type, GQF-L type, GQF-F-type expansion joint device for stretching the amount of 80mm below the bridge joints, GQF-MZL type expansion joint device is by the side beams, beams, beam Modular bridge expansion joint devices and interlocking institutions, and for stretching the amount of 80mm-1200mm of large and medium span bridges. www.htgcxj.com 

keywords: Expansion joints, bridge expansion joints, Modular Expansion Joints,