The Study Of Several Problems Of PC Continuous Rigid Frame Bridge Prestress Design

With the rapid transit development of China's highway, more large span bridge was needed to span great rivers and bays, PC continuous rigid frame bridge emerged as the times require and was developed fleetly in recent years. In the prestress design of PC continuous rigid frame bridge, there are two problems in dire need of solving. They are: the calculation of PC continuous rigid frame bridge long cable prestress loss; the design of PC continuous rigid frame bridge vertical prestress.As to the study of PC continuous rigid frame bridge long cable prestress loss, combining the result of finite element analysis with the data of stress test, this paper analyses the cause of the nonlinear variation of friction loss, modifies involved parameter ( such as friction modulus k u etc), puts forward corresponding solving measures, and accumulates experience for the later design of the same style bridge.As to the study of PC continuous rigid frame bridge vertical prestress design, this paper introduces a concrete strength criterion in the state of multi-axis and complicated stress, namely a pattern of bi-shear strength criterion with three parameters; combining the study of the bevel sections anti-shear strength of pre-stressed concrete beam, analyzes the problems how to enhance the strength of the concrete in the state of bi-axis stress and the bevel sections anti-shear strength of the pre-stressed concrete beam and brings forward the vertical pre-stressed calculation formula in consideration of enhancing concrete strength.