考虑压型钢板影响的钢筋桁架-混凝土组合板静力性能设计方法

Design Methods for Static Performance of Steel-Bars Truss Slabs Considering Effects of Profiled Steel Sheets

为研究钢板底模对钢筋桁架-混凝土组合板的受弯承载力、短期及长期刚度的影响,首先评述了国内外钢筋混凝土板与钢-混凝土组合板设计方法的特点及适用范围,采用现有钢筋桁架-混凝土组合板的试验结果验证了各设计方法的可靠性;在此基础上,提出了考虑压型钢板影响的钢筋桁架-混凝土组合板静力性能设计方法。结果表明:极限荷载作用下压型钢板可达到屈服强度,带钢板底模的组合板试件比无钢板底模的试件受弯承载力提高47.0%~60.3%;尽管正常使用荷载作用下压型钢板的应变略低于理论计算值,但其对组合板短期刚度的贡献非常明显,提高幅度达112.1%~180.0%;钢板底模的密闭作用导致混凝土收缩变形沿截面高度的分布是非均匀的,组合板长期挠度增大119.7%;试件跨高比与环境相对湿度是影响钢筋桁架-混凝土组合板收缩性能的关键参数,考虑非均匀收缩影响提出的长期挠度设计公式具有较高的预测精度,公式计算结果与有限元分析结果比值的均值为0.951~0.979,判定系数R~2为0.657~0.873。

To investigate the effects of profiled steel sheets on the flexural capacity,short-term and long-term stiffness of steel-bars truss slabs,typical design methods for reinforced concrete slabs and composite steel-concrete slabs were first summarised and evaluated,and benchmarked against the test results reported by the authors and other researchers.Design procedures were then proposed for steel-bars truss slabs considering the influence of profiled steel sheets.The results indicated that the profiled steel sheets in steel-bars truss slabs could reach their yield strength under ultimate limit state,and therefore an increase of 47.0%-60.3% in the flexural capacity was observed for steel-bars truss slabs when compared to slab samples without profiled steel sheets;the contribution of profiled steel sheets to the short-term stiffness was significant,and the increase magnitudes were 112.1%-180.0%,despite the strains of profiled steel sheets under the normal service load were smaller than expected;the sealing effect of profiled steel sheets resulted in uneven distribution of shrinkage deformation of concrete along the height of cross section,and an additional 119.7% deflection could be obtained accordingly.Span-to-depth ratio and ambient relative humidity were the key factors that influenced the shrinkage performance of steel-bars truss slabs,and the proposed design procedures accounting for non-uniform shrinkage distributions showed good accuracy with the test results,with the ratio of 0.951-0.979 and the correlation coefficient R~2 of 0.657-0.873.