地震作用下高烈度区连续刚构桥参数敏感性分析

大跨连续刚构桥的参数变化对其地震响应影响较大,为了进一步研究地震作用下刚构桥各参数变化对桥梁内力的影响,以一连续刚构桥为例,采用正交数值试验的方法,以主梁跨中横桥向弯矩、墩顶顺桥向弯矩、墩底顺桥向弯矩及墩底横桥向弯矩为考核指标,分析地震作用下结构参数(边中跨比、梁底幂次、墩高比)的变化对桥梁内力的影响规律及其参数敏感性。研究结果表明:对于跨中横桥向弯矩,墩高比对其影响较大,墩高比的增加可使弯矩值最大增加28%;对于墩顶顺桥向弯矩、墩底顺桥向弯矩以及墩底横桥向弯矩,边中跨比对其影响较大,边中跨比的增加可使弯矩值最大分别增加51%、55%和52%。高烈度区的桥梁设计应重视边中跨比及墩高比的选择。

Parameter Sensitivity Analysis of Continuous Rigid-frame Bridgesin High Seismic Intensity Regions under Seismic Action

The seismic response of long-span, continuous rigid-frame bridges is greatly affected by a parameter change. To further study the influence of various parameters of rigid-frame bridges on the internal force of the bridge under the action of an earthquake, the orthogonal numerical test method was adopted with a continuous rigid-frame bridge as an example. The transverse bending moment at the middle span of the main beam, the longitudinal bending moment at the pier top and bottom, and the transverse bending moment at the pier bottom were taken as the evaluation indices. The influence law of structural parameters (side span-to-central span ratio, power of beam bottom, pier height ratio) on the internal force of the bridge under seismic action, and the parameter sensitivity were analyzed. Results indicated that the pier height ratio had a great influence on the mid-span transverse bending moment. Additionally, it was observed that with the rise in pier height ratio, the maximum bending moment value increased by 28%. The side span-to-central span ratio had a large influence on both the longitudinal bending moment at the pier top and bottom and the transverse bending moment at the pier bottom, and with the increase of side span-to-central span ratio, the maximum value of the bending moment increased by 51%, 55%, and 52%, respectively. Bridge design in high-intensity areas should pay close attention to the choice of side span-to-central span ratio and pier height ratio.