External prestressed reinforcement project
The external prestressed reinforcement method is a method of strengthening structural members by applying prestressed steel tie rods. The characteristic is that the force of the post-tension rod is forced by prestressing means, which changes the internal force distribution of the original structure and reduces the stress level of the original structure to make general reinforcement The unique stress-strain hysteresis phenomenon in the structure can be completely eliminated. Therefore, the post-added part can work well with the original structure, and the overall load-bearing capacity of the structure can be significantly improved.
Compared with the reinforcement method of welding (or pasting) reinforcement (or steel plate) at the bottom of the beam, the external prestress reinforcement method does not require the removal of the concrete protective layer, and the damage to the beam body is small, and the reinforcement does not affect or affect the traffic. The economic effect of restoring or improving the load level of the bridge is obvious.
According to the different force requirements of the reinforced structure, the prestressed tie rod reinforcement methods are divided into three types, namely, horizontal tie rods, through-type tie rods and combined tie rods. The horizontal tie rod is suitable for the reinforcement of insufficient flexural bearing capacity of the front section. At the same time, it can reduce the deflection of the beam and reduce the crack width of the original member. Down-bearing tie rods are suitable for reinforcement of bending members with insufficient shear capacity of oblique section and bending capacity of normal section. At the same time, it can reduce the deflection of the beam and reduce the crack width of the original member. Combined tie rods generally use two horizontal tie rods and two through tie rods, which are suitable for reinforcement where the bending bearing capacity of the normal section is seriously insufficient and the shear bearing capacity of the oblique section is slightly insufficient. At the same time, it can also reduce the deflection of the bending member. Reduce the width of the crack