复杂荷载下中空夹层钢管混凝土桥墩的受力性能研究

Concrete filled double skin steel tube piers have potential application advantages in piers of bridge engineering due to the light self-weight, good seismic capacity and convenient construction. In this project, the quasi-static test and three-dimensional finite element analysis will be carried out for studying the mechanism of concrete filled double skin steel tube single piers and double piers with rectangular concrete filled steel tube coupling beams under combined compression-bending-shear-torsion effect. Based on the principle of conventional fiber-beam model considering non-linear axial-bending effect, the strain geometrical equations on section under complex stress state, the effective constitutive models of the confined concrete material at spiral cracking state and the steel material considering spatial buckling effect will be derived, and the refined bar model with consideration of compression-bending-shear-torsion combined effect of concrete filled double skin steel tube piers will be established. Then the finite element will be developed using the UEL subroutine of general finite element program ABAQUS. Then the seismic analysis on curved bridges with concrete filled double skin steel tube piers will be made, and the design method considering combined compression-bending-shear-torsion for concrete filled double skin steel tube piers under complex load will be proposed. The research results of this project have scientific significance and application value for the application and development of concrete filled double skin steel tube piers in bridge engineering.

中空夹层钢管混凝土桥墩具有自重轻、抗震性能好、施工方便等特点，在桥梁工程中具有潜在的应用优势。本项目将开展复杂荷载下考虑压弯剪扭耦合效应的中空夹层钢管混凝土单柱墩和采用矩形钢管混凝土连梁的双柱墩的拟静力试验研究和三维精细化有限元分析，揭示其在复杂荷载条件下的受力机理，并基于仅能考虑轴力-弯矩非线性效应的传统纤维梁模型的基本原理，通过推导复杂应力状态下截面应变几何方程、螺旋开裂状态下约束混凝土的等效本构方程和考虑空间相关性屈曲的钢材等效本构方程，建立考虑压弯剪扭耦合效应的中空夹层钢管混凝土桥墩的精细化杆系分析模型，然后在通用有限元程序ABAQUS的子程序UEL中进行有限单元二次开发，开展采用中空夹层钢管混凝土桥墩的曲线高架桥抗震性能分析，提出复杂荷载下考虑压弯剪扭耦合效应的中空夹层钢管混凝土桥墩的设计方法。项目研究成果对中空夹层钢管混凝土桥墩在桥梁工程中的推广和发展具有科学意义和应用价值。

中空夹层钢管混凝土桥墩具有自重轻、抗震性能好、施工方便等特点，在桥梁工程中具有潜在的应用优势。本项目开展了复杂荷载下考虑压弯扭耦合效应的矩形和方形截面中空夹层钢管混凝土单柱墩拟静力试验研究和三维精细化有限元分析，揭示其在复杂荷载条件下的受力机理和耗能性能，并基于数值参数分析研究了材料属性和截面空心率等参数对矩形和方形截面中空夹层钢管混凝土桥墩承载性能和破坏模式的影响规律，研究结果表明：纯扭作用下矩形和方形截面中空夹层钢管混凝土单柱墩中的内外钢管和夹层混凝土分别处理拉剪和压剪应力状态。矩形和方形截面中空夹层钢管混凝土单柱墩在纯扭和压扭拟静力往复荷载作用下均具有较好的耗能性能和延性变形性能。当轴压比小于0.2时，轴压荷载对矩形和方形截面中空夹层钢管混凝土单柱墩的抗扭承载性能影响很小，可不考虑轴压荷载的影响；当轴压比大于0.2时，轴压荷载的增加将使矩形和方形截面中空夹层钢管混凝土单柱墩得抗扭承载力性能下降。压弯扭往复作用下矩形和方形截面中空夹层钢管混凝土单柱墩的破坏模式为柱脚处钢管鼓屈，可采取增设加劲板等措施增强钢管和混凝土的组合性能，进而增强构件的整体抗变形能力。通过数值参数分析得到了材料属性（如钢管屈服强厚度和壁厚、混凝土强度）和截面空心率对压弯扭荷载作用下矩形和方形截面中空夹层钢管混凝土单柱墩压弯扭相关关系影响很小，并提出了复杂荷载下考虑压弯扭耦合效应的矩形和方形截面中空夹层钢管混凝土桥墩的设计方法。基于受力机理分析结果，提出了压扭荷载下矩形和方形截面中空夹层钢管混凝土单柱墩的抗扭承载力预测方法，可供工程设计参考。项目研究成果对中空夹层钢管混凝土桥墩在桥梁工程中的推广和发展具有科学意义和应用价值。