铁路实体墩墩顶温差位移及规范适应性研究

Research on Temperature Difference Displacement of Railway Solid Pier Top and Adaptability of Code

温差引起的墩顶位移是设计中一项重要指标,为填补现行2017年版桥规墩顶温差位移无可用计算公式的空缺,以满足规范提出的验算墩顶位移必须考虑0.5倍温差的要求,基于力学平衡和几何关系,通过严密的理论推导,得到了实体桥墩在线性和非线性温差温度场作用下各自的墩顶位移计算公式。通过位移等效得到等效线性温度可取5℃,并将等效线性温差公式用于通用图检算。研究结果表明:(1)理论推导的实体墩温差墩顶位移计算公式可弥补2017年版桥规计算公式的空缺;(2)通过对线性温度场和非线性温度场等效分析,得到等效线性温差为5℃,与德国规范一致;(3)对于已知温度场的桥墩,可采用非线性温度场计算公式,对于设计中缺少温度场的,可采用等效线性温度场计算公式;(4)实体墩通用图验算结果显示,温差墩顶位移随着墩高增大而增大,温差贡献的水平位移可达允许折角的12%。

The pier top displacement caused by temperature difference is an important index in the design.In order to fill the vacancy of applicable calculation formula for pier top temperature difference displacement in the current 2017 bridge code,the requirement of 0.5 times displacement of temperature difference should be taken into account in the code to check pier top displacement.Based on the mechanical balance and geometric relationship,the pier top displacement calculation formulas in both linear and nonlinear temperature fields are deduced respectively through strict theoretical derivation.The equivalent linear temperature could be taken as 5℃by displacement equivalence,and the equivalent linear temperature difference formula is used to check the general chart.The research results show that:(1)The calculation formula of pier top displacement of solid pier temperature difference derived theoretically can make up for the vacancy of calculation formula of 2017 bridge code;(2)Through the equivalent analysis of linear temperature field and nonlinear temperature field,the equivalent linear temperature difference is 5℃,which is consistent with the German Code;(3)For the pier with known temperature field,the calculation formula of nonlinear temperature field could be used,while for the pier without temperature field,the calculation formula of equivalent linear temperature field could be applied in design;(4)The check results of the solid pier general chart show that the displacement of pier top increases with the increase of pier height,and the horizontal displacement contributed by temperature difference could reach about 12%of the allowable bending angle.