An existing concrete-filled steel tubular arch(CFST)bridge in the mountainous area that has a main span of 430 m is used as a case to study the causes of debonding between the steel tube and core concrete in the CFST arch.The full-scale model of the arch-crown segment was prepared to test the effects of uneven temperature field on the debonding under the joint action of strong solar radiation and large temperature difference.The temperature field distribution in the model was analyzed and the debonding mechanism under uneven temperature field was studied.The results demonstrate that a radial temperature field during hydration and operation stages can be simplified as a multi-segment polyline.At 14:00,the temperature at hydration stage showed sign of from decreasing through increasing to decreasing along vertical diameter(from upsun to downsun),and there was a surface of large temperature difference near the D/8-3D/8 upsun interface.Whereas at operation stage,the temperature showed asymmetrical distribution of from decreasing through keeping constant to increasing(from upsun to downsun),and the great temperature difference occurred in the range from steel tube and concrete interface to the interface distancing D/8 to it.The debonding mechanism at hydration and operation stages can be explained as:under the action of temperature field,the maximum longitudinal stress difference in the steel tube and concrete interface can reach up to 82.6 MPa(hydration stage)and 61.95 MPa(operation stage),maximum interface radial tensile stress are 0.8 MPa(hydration stage)and 2.06 MPa(operation stage),respectively,all surpassing the bond strength between steel tube and core concrete.
关键词
钢管混凝土拱桥/水化热温度场/不均匀温度场/纵向应力/径向应力/脱空机理/模型试验
Key words
concrete-filled steel tubular arch bridge/hydration heat temperature field/uneven temperature field/longitudinal stress/radial stress/debonding mechanism/model test
维普
万方数据