Bridge expansion is an important element of the bridge structure, due to various factors (such as temperature, wind, vehicle load changes, concrete creep, etc.) cause changes in length of the bridge, you need to set the end of the beam position telescopic device, in order to ensure free beam Retractable flat surface displacement and states and reduce road bumps, prevent sewage deck, piers and other debris falling into the building and thus corrosion pier bearing and so on. Construction of roads and bridges to provide the highest quality products side, the best quality service. Welcome to negotiate!