干寒地区新型波形钢腹板组合箱梁温度效应分析

为探索干寒地区新型波形钢腹板组合箱梁桥的温度场分布特征和温度效应，弥补现行规范中缺乏其温度梯度模式定义的不足。本文以西北干寒地区某新型波形钢腹板组合箱梁桥为研究对象，基于现场温度观测数据，分析该新型组合结构在日照作用下的温度分布规律，并运用最小二乘法拟合提出其二维温度梯度模式；建立新型波形钢腹板组合箱梁全桥精细化有限元模型，并通过实测温度梯度函数计算该桥的温度响应；探析压型钢板对新型波形钢腹板组合箱梁温度应力的影响规律。研究结果表明：基于现场实测数据拟合的竖向分段多项式和横向指数函数组成的新型波形钢腹板组合箱梁二维温度梯度，与实测温度场计算值吻合良好，可为该地区类似工程温度荷载计算提供参考；日照温度作用下，新型波形钢腹板组合箱梁顶板与腹板交界面存在明显的温度梯度；翼缘板上缘、顶板-腹板交界面和各箱室中轴线处出现的最大横向拉应力分别为2.42 MPa、1.83 MPa和1.26 MPa，可能引起桥面板开裂，在设计中应给予重视；实测温度梯度下，闭口型压型钢板可使各箱室顶板中轴线上缘横向拉应力降低0.5 MPa以上，对桥面板抗裂有利，而开口型压型钢板可使各箱室翼缘板上缘横向拉应力提高15%~18%，对桥面板抗裂不利。

Analysis on Temperature Effect of New-pattern Corrugated Steel Web Composite Box Girder in Dry Cold Region

In order to explore the temperature field distribution characteristics and thermal effect of corrugated steel web box girder bridge in dry cold region, and to make up for the lack of the definition of temperature gradient mode of CSW box girder bridge in the current code.In this paper, a new-pattern composite box girder bridge with CSWs in dry cold region of Northwest China is taken as the research object. Based on the field thermal observation data, the temperature distribution law of the new composite structure under the action of sunshine is analyzed, and the 2D temperature gradient model is proposed by least square fitting.By establishing the refined FEM of the new-pattern composite box girder with CSWs, the temperature response of the bridge is calculated based on the measured temperature gradient function, and the influence of profiled steel plate on the thermal stress of the composite box girder is analyzed.The results show that the 2D temperature gradient of CSW composite box girder composed of vertical piecewise polynomial and transverse exponential function based on field measured data is in good agreement with the calculated value of measured temperature field,which can provide necessary reference for the calculation of similar engineering temperature load in this climate area.Under the action of solar temperature, there is a significant temperature gradient at the interface between the top plate and the web plate of the new-pattern CSW composite box girder.Transverse tensile stresses up to 2.42 MPa, 1.83 MPa and 1.26 MPa may appear at the upper edge of the flange plate, the top plate web interface and the central axis of each box chamber, which may cause cracks in the deck and should be paid attention to in the design.Under the measured temperature gradient, the transverse tensile stress of the upper edge of the central axis of each box chamber roof can be reduced by more than 0.5MPa by the closed profiled steel sheet, which is beneficial to the crack resistance of the bridge deck. While the open profiled steel plate can increase the transverse tensile stress of the upper edge of the flange plate of each box chamber by 15% ~ 18%, which is unfavorable to the crack resistance of the bridge deck.