钢-混凝土组合梁非线性变形研究

STUDY ON NON-LINEAR DEFLECTION OF COMPOSITE STEEL-CONCRETE BEAMS

目前,对于钢-混凝土组合梁在荷载长期效应下挠度的研究,我国现行规范是通过降低弹性模量的方法来考虑荷载的长期效应,而没有充分考虑混凝土的收缩、徐变的影响。此外,组合梁交接面的滑移对长期挠度的影响也不可忽视。综合现有研究成果,选取影响挠度的主要影响因素:混凝土的收缩、徐变和抗剪连接件的滑移进行考虑,推导出考虑混凝土的徐变、收缩和剪切件滑移的钢-混凝土组合梁长期挠度计算公式,并对一高层建筑中的两根典型组合梁进行了现场监测与分析。理论分析和实测结果表明:用现行规范中的计算方法计算出的组合梁的长期挠度值偏小,因此,对组合梁的设计和施工提出了一些建议。

At present, the deflection of composite steel-concrete beams under long-term loads is mainly analyzed by the reduced elastic modulus in the national code. The shrinkage and creep of concrete are not considered adequately, also, the interface slip between steel and concrete should not be ignored for long-term deflection. Therefore, a non-linear deflection formula of composite steel-concrete beams under long-term loads is deduced by the main influent factors such as shrinkage, creep, and interface slip, considered and synthesized by previous researches. Two representative composite beams of a tall building are also monitored in situ to study the non-linear deflection, the deflection values of the theoretical calculation and measurement show that the values calculated by the code are smaller than that of the theoretical calculation and the practice. Thus some suggestions for the design and construction of composite beams are proposed.