高温沥青混合料摊铺时正交异性钢桥面板温度响应分析

Analysis on Temperature Response of Orthotropic Steel Bridge Deck during Paving of High-temperature Asphalt Mixture

为了研究高温沥青混合料摊铺时正交异性钢桥面板在温度影响下的结构受力响应,基于瞬态温度场理论和热力学边界假设条件,确定数值模拟所需的各项热力学参数,以及通过试验-数值模拟方法得到了界面热阻参数。采用生死单元法建立了正交异性钢桥面板在高温沥青混合料摊铺全过程的时变温度场有限元模型,并结合某长江大桥在浇注式沥青混凝土摊铺过程中的实测数据,验证了该模拟方法的可靠性。基于该模型分析了高温摊铺下正交异性钢桥面板温度场时空变化规律。结果表明,在开始摊铺浇注式沥青混凝土30 min左右,摊铺区域处跨中钢桥面板上最高温度达到95℃,在结构分析中应考虑温度应力;位于摊铺区域的钢桥面板主要承受压应力,最大压应力温度增量139 MPa,位于非摊铺区的钢桥面板主要受拉应力,最大拉应力温度增量70 MPa;顶板温度的横向影响范围在摊铺边缘左右各约1 m,横隔板处顶板的纵向温度较其他截面略低6~7℃。该分析结果可为设计人员在计算摊铺施工时提供不利影响分析依据,并为施工人员在摊铺过程中进行施工监测提供参考。

In order to study the structural force response of orthotropic steel bridge deck under the influence of temperature during paving of high-temperature asphalt mixture,based on the transient thermal field theory and thermodynamic boundary assumptions,the thermodynamic parameters required for numerical simulation are determined,and the interface thermal resistance parameters are obtained by the test-numerical simulation method.The corresponding time-varying temperature field finite element model in the whole process of paving is established by birth-death element method.Combining with the measured data of a Yangtze River bridge during paving of the gussasphalt pavement,the reliability of the simulation method is verified,the spatio-temporal variation of the temperature field of the orthotropic steel bridge deck under high temperature paving is analyzed accordingly.The result shows that(1)about 30 min after the start of paving the gussasphalt concrete,the highest temperature at the steel bridge deck of mid-span in the paving area reaches 95℃,and the temperature stress should be considered in the structural analysis;(2)the steel bridge deck in the paving area are mainly subjected to compressive stress,and the maximum compressive stress increment is 139 MPa,while the steel bridge deck in the non-paving areas are mainly subjected to tensile stress,and the maximum tensile stress increment is 70 MPa;(3)the horizontal influence range of the roof temperature is about 1 m at the left and right sides of the paving edge,while the longitudinal temperature of the roof at the diaphragm is slightly lower than other sections by 6-7℃.The analysis result can provide designers with a basis for analysing adverse influence when calculating paving construction,and provide a reference for construction personnel to monitor construction during the paving process.