太阳辐射作用下钢管混凝土拱不均匀温度场及其引起的脱空分析与试验研究

为厘清太阳辐射作用下钢管混凝土拱肋内部的不均匀时变温度场,剖析其对钢管混凝土脱空效应的影响机制,并为钢管混凝土拱桥的脱空病害防治奠定理论基础,依托受日照辐射较强的贵州香火岩特大跨钢管混凝土拱桥实际工程,建立考虑钢管与混凝土界面接触关系的精细化温度-应力耦合数值模型;基于ASHRAE晴空模型及温度场计算理论,开展了钢管混...

Analysis and Experimental Study of Uneven Temperature Fields in Concrete-filled Steel Tubular Arches Under Solar Radiation and Its Void Effect

In order to clarify the uneven time-varying temperature field inside the concrete-filled steel tube( CFST) arch rib under the action of solar radiation,analyze its influence on the void effect of the CFST,and lay a theoretical foundation for the prevention of CFST voids,a refined temperature-stress coupling numerical model considering the contact relationship between the steel tube and concrete interface was established using the actual Guizhou Xianghuoyan extra-large CFST arch bridge project that is exposed to intense solar radiation. Based on the ASHRAE clear sky model and temperature field calculation theory,an analysis of the time-varying temperature field of the CFST arch rib under solar radiation was carried out. Moreover,the temperature distribution of the CFST arch rib and its variation with time was revealed,and the approximate formula for calculating the temperature gradient of the CFST section is provided. Combined with the stress criterion of the void,the rib section was calculated along with the void height at different positions in the radial direction. Furthermore,the cross-sectional void distribution pattern of the CFST arch rib was clearly defined. Based on the induced vibration theory,the arch sections,which were mainly affected by the temperature and voids,were selected,and the test of the CFST bridge was carried out. Along with the theoretical analysis,the reliability of the theoretical analysis was verified. Research indicates that under the action of solar radiation,the temperature field of the CFST section is highly nonlinear with respect to time and space distribution. The core concrete temperature lags behind that of the outer steel tube,and the maximum temperature difference between the steel tube and the core concrete exceeds 25 °C. Additionally,the interface tensile stress,caused by the uneven temperature difference of solar radiation reaches 1. 4-1. 5 MPa,in which causes the hoop void height of the CFST approaching 0. 11-0. 13 mm. The detection method of the CFST arch ribs,based on the induced vibration method,can help identify the possibility of voids and indicates that the solar radiation slightly increases the void degree in the CFST.