Study On The Structural Behaviors Of Externally Prestressed Concrete Continuous Beam

It was above 70 years since the external prestressing technology had been used in constructing bridges. But, hitherto, this kind of technology has not been universally applied. It is one of primary reasons that people had no sufficient knowledge on constructural behavior of concrete beam with external prestress, and the application of the external prestressing technology was ''restraint.Therefor,researchers of home and overseas have carried out a series of study on concrete beams with external prestress. Reviewing study on concrete beams with external prestress home and overseas, we have found that these studies most deal with simple supported beam and rarely deal with continuous beam so as to people's knowledge of continuous concrete beam with external prestress is scanty. So it is necessary to do an in-depth study on continuous concrete beam with external prestress.This paper is based on scientific research project on municipal construction of Chengdu city "study on development and application of new technology on high strength concrete bridge with external prestress", probes into structural behavior of concrete continuous beam with external prestress from several aspects as follows:1.Design and finish static test of 4 continuous beams with external prestress that have different PPR. Mechanic performance of model beams is studied.2.Development of cracking and deformation of model beams with different PPR are studied and analyzed. Afterwards,calculation method of defection of model beams is put forward.3.The redistribution of moment of model beams and its effect factors are studied and analyzed.4.The stress increaseing rule of external prestressing tendon is studied and analyzed.Simple calculation method of stress increment of external prestressing tendon is put forward.