钢管混凝土柱-软钢消能部件组合式高墩的抗震性能与设计理论

Currently, seismic designs of both highway and railway bridges with tall piers are lack of an suitable design code. The Minjiang large bridge across the Miaoziping reservoir suffered seriously damage in the Wenchuan earthquake of March 13, 2008. The heavy damage of the bridge indicates that current seismic design procedure for bridges with tall piers is inadequate. More and more bridges with tall piers will be built with rapid and all-round development of the Western China. How to ensure the seismic resilience of the bridges with tall piers, which will be built in the high seismicity and high intensity area of the Western China, has become a major demand for the sustainable social and economic development of China. In this project, an innovative tall box pier system composed concrete-filled steel tubular (CFST) columns and steel plate energy dissipation members is proposed based on the principle of earthquake-resilience design. Taken the highway bridges with tall piers as the research background, the seismic performance, design theory and design procedure for the new composite tall box pier are comprehensively studied by methods of theoretical and numerical analysis and test. Simplified calculation formula of ultimate compression capacity and stiffness of the new composite tall box pier and design method for parameter optimization of steel plate energy dissipation members are also proposed. A simplified seismic design theory for the bridges with new composite tall box piers is established based on the seismic design principle of structures with energy dissipation devices. The theory will be verified from the results of shaking table array test. This project will play an important role in development of new aseismic structural systems and new seismic design concepts of the bridges with tall piers.

当前公路和铁路高墩桥梁抗震设计均无规范可循，2008年汶川地震中庙子坪岷江特大桥遭受严重震害，暴露出高墩桥梁抗震设计尚存在诸多问题。随着我国西部大开发的加速发展和全面推进，高墩桥梁的建设将越来越多。如何确保建于强震频发的西部高烈度地震区高墩桥梁在震后能快速恢复功能，已成为我国社会经济可持续发展的重大需求。基于可恢复功能抗震设计原理，创新性地提出一种具有震后可恢复性的钢管混凝土柱-软钢消能部件组合箱形截面高墩结构体系；以公路高墩桥梁为背景，综合采用理论分析、模型试验和数值分析等手段，系统深入地研究新型组合式高墩的抗震性能、设计理论和设计方法，提出其正截面受压承载力和刚度的简化计算公式以及软钢消能部件的参数优化设计方法；基于消能减震结构设计原理，提出新型组合式高墩桥梁的简化抗震设计理论，并进行地震模拟振动台台阵试验验证。本项目研究将对高墩桥梁抗震结构体系的创新和抗震设计理念的发展起到推动作用。

综合采用理论分析、模型试验和数值分析等手段，开展了系列研究：（1）针对公路高墩桥梁，提出新型组合截面高墩体系的构造细节和设计原则，推导建立了其抗侧刚度的简化计算公式，给出组合截面设计参数取值建议；（2）开展了 6个1/10缩尺比例的新型组合截面高墩受压性能试验和有限元模型参数拓展分析，明确了其受压性能，提出了其正截面受压承载力的实用计算公式；（3）开展7个1/5缩尺比例的高墩模型拟静力试验及有限元模型参数拓展分析，试验结果表明：新型组合截面高墩模型在钢管混凝土柱屈服之前的滞回曲线基本符合双线性模型，平钢板模型的损伤模式为平钢板出现明显的弹塑性屈曲变形，波形钢板模型的损伤模式为波形钢板出现明显的面内剪切变形，符合设计预期；结合参数分析发现，影响组合截面高墩抗震性能的主要因素为钢管厚度和软钢板厚度，提出选择合适的软钢板厚度是决定组合截面高墩耗能能力的关键；（4）开展了2个新型组合截面高墩模型验证性的振动台试验，对新型组合式高墩桥梁的抗震性能进行了检验；将新型组合截面高墩桥梁视为消能减震结构，建立了其简化的抗震计算理论，提出用于E2地震作用下简化抗震计算的等效弹性模型概念；通过试算分析，初步确定了等效弹性模型的等效刚度和等效附加阻尼比。本项目研究成果对高墩桥梁抗震结构体系创新和抗震设计理念发展起到了推动作用。