High Pier Span Prestressed Concrete Continuous Rigid Frame Bridge Load Test To Assess The Technical Research

Now, many long-span PC continuous rigid frame bridges with tall piers have been built in our country, especially in northwest part. As more and more such bridges are built, more attention is paid to its actual active state during trial load acting; actual bearing capacity and so on. It is significant and valuable to study loading test assessment technique of these bridges for ensuring the safety of these bridges in service and completing the technique of loading test theory.As an important part of communication scientific research item of Shaanxi-'Field test and bearing capacity judging method research for long-span PC continuous rigid frame bridges with tall piers' (04-14K). Based on Xinggou bridge in Shaanxi YU-YAN expressway, space emulate finite element model is established with beam and shell elements in bridge dedicated program and Ansys. This model analyses the controlling sections of moment of flexure, strain, shear, displacement against spar boom and pier shaft., and matches the measured value and calculated value of crosswise enlarge coefficient and shear lag phenomena. The testing section allocation against combination and pier ground is approached. General suggestion against lengthwise testing sections and measuring point locating on the sections are extracted.Result indicates: the moment of flexion and strain worst-case section are not the same section because many long-span PC continuous rigid frame bridges are variable cross-sections. Generally true strain is reflected by measuring strain of the sections during loading test. ,so it's quite necessary to use strain worst-case section as testing section.. During general loading test, the top pier section is unused, but it is more unfavourable than the ground pier section. So the top pier section must be applied as testing section.This paper offers clear expression of stress characteristic of long-span PC continuous rigid frame bridges, and influencing factor of actual measurement effect during the loading test. It also gives some useful conclusions to the loading test of these bridges.