弹性模量取值对渡槽结构抗震安全复核影响的探讨

Discussion on the Influence of Dynamic Elastic Modulus Value on Structural Safety of Aqueducts under Earthquake

通过对某渡槽进行现场动力测试获得结构在自然脉动下的振动特性,结合三维有限元模态反分析,获得其排架混凝土的动弹性模量状况,根据现场质量检测的结果,对排架混凝土动弹性模量的取值及基础约束条件做出最合理的判断。抗震分析表明,排架混凝土动弹性模量的取值会对该渡槽结构的抗倾覆稳定造成比较大的影响。因此,建议在渡槽抗震复核中应着重考虑混凝土的动弹性模量,利用振型分解反应谱法分析时能够对地震作用效应进行更充分的估算,提高结构抗震安全评估的可靠性。

The vibration characteristics of an aqueduct under natural pulsations are obtained through field dynamic testing,and the dynamic elastic modulus E d of bent frame concrete of the aqueduct is obtained through three-dimensional finite element modal inverse analysis.In accordance with the in-situ non-destructive concrete quality inspection results,the most reasonable estimation of E d of bent frame concrete and the constraint conditions of foundation are obtained.The seismic analysis shows that different E d value assignment has a significant impact on the overturning stability of aqueduct.Therefore,it is recommended that proper dynamic instead of static elastic modulus should be adopted in the seismic safety review of aqueducts to ensure an accurate calculation of earthquake force when using modal superposition method,thus to achieve a reliable safety assessment of those structures.