钢管混凝土空间组合桁架连续梁桥地震响应影响分析

发布时间：2018-12-15 01:06

【摘要】：为揭示河谷场地"钢管混凝土空间组合桁架连续梁桥"地震响应规律,以京昆高速公路"干海子特大桥"为工程背景,建立其三维有限元动力计算模型;采用有限元与间接边界积分方程耦合法(FEM-IBIEM耦合法)进行场地反应计算,并通过多点激励(改进LMM法)方式进行地震动输入,研究行波效应、局部场地效应对其地震响应影响,并和一致激励进行比较,结果表明:该类桥梁低墩较高墩对地震动更敏感,且在墩高突变区域最为明显;较一致激励和高墩和对应梁跨,行波效应增大其墩底轴力、跨中下弦杆和斜腹杆轴力,但减小其它量测值;低墩和对应梁跨,行波效应减小其墩底弯矩、墩顶位移和跨中位移;较一致激励和行波效应,局部场地效应显著增大了大多桥墩和梁跨的位移和内力,且对墩高突变处低墩、梁跨的放大作用最为明显,因此对于河谷场地中"钢管混凝土空间组合桁架连续梁桥"抗震设计,特别是墩高突变区的低墩和梁跨,必须重点考虑局部场地效应的影响。
[Abstract]:In order to reveal the seismic response law of "concrete filled steel tube space composite truss continuous beam bridge" in the valley site, the 3D finite element dynamic calculation model of "Qianhaizi Bridge" of Beijing-Kunming Expressway is established. The site response was calculated by using the coupling method of finite element and indirect boundary integral equation (FEM-IBIEM), and the ground motion was inputted by multi-point excitation (improved LMM method) to study the traveling wave effect. The effect of local site effect on seismic response is compared with uniform excitation. The results show that the low pier of this kind of bridge is more sensitive to ground motion than the high pier and the most obvious is in the abrupt region of pier height. The traveling wave effect increases the axial force at the bottom of the pier, increases the axial force at the bottom of the pier, and decreases the other measured values, but decreases the other measured values, while the traveling wave effect decreases the bending moment at the bottom of the pier, the displacement of the top of the pier and the displacement of the middle span of the pier. Compared with uniform excitation and traveling wave effect, the local site effect increases the displacement and internal force of most piers and beam spans significantly, and the amplification of beam spans is most obvious for the low piers with abrupt changes in pier height. Therefore, for the seismic design of concrete filled steel tube space composite truss continuous beam bridge in valley site, especially for the low pier and beam span in the high abrupt zone of pier, the influence of local site effect must be considered.
【作者单位】：天津城建大学土木工程学院;天津市土木建筑结构防护与加固重点实验室;
【基金】：国家自然基金项目(51678390) 天津市自然科学基金重点项目(12JCZDJC28900) 天津市科技兴海项目(KJXH2012-19)
【分类号】：U442.55

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