Study On Natural Vibration Of Simple-supported Beam Reinforced By External Prestressing

In the reinforcement of existing struetures, the method of extemally prestressed reinforcement is widely used and popularized, but the study in this area is still in early stage in our country when it is compared with foreign countries; Many problems have to be studied and solved. Meanwhile the dynamic question of the structures which are reinforced with external pre-stressing has been ignored. This paper takes simple-supported beams as the research object. The main task is as follows:1,Learn from the method of that Ayaho miyamoto derived the natural frequeney of composited beam reinforced by external pre-stressing, the mechanical characteristics of simple-supported beam reinforced by external prestressing is studied, there are three stages of the vibration of the reinforced beam, At the first two stages, its vibration equation and theoretical formulas of nature frequency can derivate by using clear mechanics, and experimental data verify the theoretical formulas,but the formulas are only suitable for reinforced structures which do not have large damage, or only have small cracks.2,Because the whole structure stiffness has a big change, after it is reinforced by external pre-stressing tendon, the paper fixed its stiffness based on the deflection. In this way, we can get a more precise theoretical algorithm of its frequency,and the simplified algorithm is put forward according to the existing test data.3,Based on the theory of vibration of stay-cables of the cable-stayed bridge, this paper analysis the natural vibration of externally prestressed reinforcement beam , get the calculation formula of in vitro propulsion. In the meantime, the natural frequency used in practical engineering application is studied.4,The experimental beams is imitated by using the finite element method,and the numerical simulation result is consistent with the theoretical calculation.