体外索钢箱——混凝土组合连续梁非线性结构性能试验研究

钢箱-混凝土组合连续梁负弯矩区混凝土的开裂问题影响了这类组合结构向更大跨度的发展。针对这一问题，提出在钢箱-混凝土组合连续梁中施加体外索的新技术，研究施加体外索对增强钢箱一混凝土组合连续梁负弯矩区混凝土的抗裂能力，提高钢箱-混凝土组合连续梁弹塑性结构性能的有利作用。经对比试验表明，施加体外索后，钢箱-混凝土组合连续梁负弯矩区混凝土的开裂荷载提高2．8倍，组合连续梁的弹塑性抗弯刚度提高29．35％，承载力提高34．67％，结构性能显著提高。在试验研究基础上，分析钢箱-混凝土组合连续梁负弯矩区局部力学性能与整体非线性结构性能的关系，揭示体外索提高钢箱-混凝土组合连续梁弹塑性结构性能的力学实质，给出承载力计算建议。研究结果可作为体外索钢箱-混凝土组合连续梁工程应用和理论分析的参考。

Experimental Study on Nonlinear Structural Performance of External Cable Steel Box Concrete Composite Continuous Beam

The cracking problem of concrete in the negative moment zone of steel box concrete composite continuous beams has affected the development of such composite structures towards larger spans. In response to this issue, a new technology of applying external cables in steel box concrete composite continuous beams is proposed, and the beneficial effect of applying external cables on enhancing the crack resistance of concrete in the negative bending moment zone of steel box concrete composite continuous beams is studied, improving the elastic-plastic structural performance of steel box concrete composite continuous beams. Through comparative experiments, it has been shown that after the application of external cables, the cracking load of concrete in the negative bending moment zone of the steel box concrete composite continuous beam increases by 2.8 times, the elastic-plastic bending stiffness of the composite continuous beam increases by 29.35%, the bearing capacity increases by 34.67%, and the structural performance is significantly improved. On the basis of experimental research, the relationship between the local mechanical properties in the negative moment zone of the steel box concrete composite continuous beam and the overall nonlinear structural performance is analyzed, revealing the mechanical essence of external cables improving the elastic-plastic structural performance of the steel box concrete composite continuous beam, and providing suggestions for bearing capacity calculation. The research results can serve as a reference for the engineering application and theoretical analysis of external cable steel box concrete composite continuous beams