Numerical Simulation of Temperature Field of Prestressed Concrete Box Girder Bridge After Fire Exposure
The variation of the internal temperature field of the bridge with time and space under fire is the basis for studying the safety and fire resistance of the bridge structure under fire.Taking a pre-stressed box girder bridge under actual fire as an example,the fire dynamics software FDS was used to reconstruct the fire scenario of the bridge,and the surface temperature distribution pattern of the prestressed box girder under fire was studied.The internal temperature field of the box girder was cal-culated and analyzed using finite element software ANSYS,and the post-fire field test results were compared with the model calculation results.The results showed that:1)The surface temperature of the concrete structure gradually increased under fire exposure,with high-temperature areas concentrat-ed in the bottom plate area directly above the fire source,and at the intersection of the bottom plate edge and the web,reaching a maximum temperature of approximately 750 °C.2)With the continuous increase of fire time,the internal temperature of the box girder components continued to rise,and tem-perature gradient of the components kept increasing.The maximum temperature on the surface of the bottom plate was 754 °C,while the temperature at a depth of 20 cm from the surface was 28 °C.3)The relationship curve between the depth of the box girder from the surface and the calculated temper-ature was obtained by quadratic curve fitting,and compared with the recommended values in the speci-fication.The temperature variation trends were generally consistent.However,due to the differences in the temperature rise curve and component size,there were some differences between the calculated value of internal temperature and the recommended values in the specification.4)The fire-affected ar-ea on site was generally consistent with the high-temperature areas displayed by the FDS simulation of the box girder's bottom surface temperature field,with the main damage occurring at the bottom plate and web areas directly above the fire source.The numerical analysis results of the internal temperature field closely matched the field test results,indicating that the internal temperature field calculation of the components provides good accuracy.
bridge engineeringfirenumerical simulationFDSANSYStemperature field
万方数据
维普
