Abstract:The joint connection of loaded steel truss bridge is reinforced under stress, which is faced with the problems that the reinforcing member and the original component are not synchronized, the original component cannot be arbitrarily removed, and the force transmission path is complex after reinforcement. The principle of "strong joint, weak rod body" is often adopted in the design of steel truss bridge. When the joint is connected and reinforced, to connect the rod body often needs to be reinforced together. The two are inseparable. The connection structure plays a key role in the force transmission effect and its effectiveness. Based on the overhaul project of Songpu Bridge in Shanghai, the joint connection and reinforcement design of loaded steel truss bridge is studied according to the principle of controlling the existing original components to meet the requirements of current specifications. Firstly, four kinds of joint connection reinforcement schemes are analyzed. It is pointed out that the joint connection reinforcement design of load steel truss bridge should avoid the removal of the original connectors as far as possible, and should be considered as a whole with the connection structure of the rod reinforcement. Then, based on the construction scheme 4, three kinds of calculation methods and processes of joint connection reinforcement are given. And the differences of the three methods are illustrated by an example. It is proposed that the joint connection reinforcement should provide the sufficient support stiffness for the force transmission of the rod reinforcement in order to avoid the transfer of the internal force of the reinforcing member to the original member at the end of the rod. Finally, through the test results of the finished bridge, the design is corrected, and the correctness of the design method is demonstrated.
