The Research On Static And Dynamic Properties Of Prestressed Simply Supported Beam

With the development of prestress technology, the application of prestressed concrete structures in civil engineering became extensive increasingly, and related research topics emerged. Among them, the mechanical properties of post-tensioned, which including the bonded and unbonded prestressed structure, is still lack of deep study, especially the experimental study, which lack of unity inthinking and directly affect the safety and the design concept of the prestressed bridge. Based on previous studies, under the grant of traffic project of Liaoning Province, prestressed concrete girder grouting technology and performance evaluation of research ,aiming at the tested research of six post-tensioned prestressed concrete simply supported beam, the finite element software was used to simulate vibration characteristics, mainly comparing the difference between bonded and unbonded prestressed simply supported beam in seismic behavior, bearing capacity, vibration characteristic and so on, technical measures to improve the seismic safety of prestressed structures were investigated as well. Specific studies as follows:1. The low cyclic loading test is carried on six beams (bonded and unbonded respectively three), and the hysteresis curve, skeleton curve were got, comparing with the test phenomenon and the experimental data, the bearing capacity and energy capacity of post-tensioned unbonded prestressed concrete structures is superior to unbonded structures; displacement ductility and ease of damage repair are not as good as unbonded structure.2. Through the gratde tensioned prestressed vibration test for three unbonded test beams, the former third-order natural frequency of specimen was got through analyzing experimental data by DH5938 vibration analyzer, according to the tension and frequency change curves , there is a certain relationship between the test beam stiffness and the prestressed tension, but the influence is small. The prestressed reinforcement tension is controled by micro-cracks within the text beam to change stiffness. 3. According to the actual sample size and the measured to the material, the finite element structural analysis software ANSYS is used to simulate the vibration of test beams, and comparing with the test result, results are identical.so it is feasible and effective to carry out structural analysis by large-scale finite element program .