600MPa高强钢筋高强混凝土梁刚度试验研究

Research on Rigidity of High-strength Concrete Beams with 600MPa Steel Bars

分别进行了4组8根不同配筋率的配置600MPa高强钢筋与C60高强混凝土梁的刚度试验,以及1组2根配置400MPa钢筋与C60混凝土的对比梁的刚度试验研究.确定出各级荷载作用下各试验梁的截面应变变化规律,分析了开裂后正常使用阶段实测钢筋应力的变化规律,得到了配置600MPa高强钢筋高强混凝土梁的荷载-挠度全过程曲线.试验结果表明:配置600MPa级钢筋的高强混凝土梁具有良好的变形性能,荷载-挠度曲线仍为典型的三折线变化.其他条件相同时,配置600MPa高强钢筋的混凝土梁相比于配置400MPa钢筋梁的极限承载力提高了41.6%.基于试验研究结果,分析了现有国内外规范公式对于配置600MPa高强钢筋混凝土梁的刚度计算方法的适用性,进而推荐了适用于600MPa高强钢筋高强混凝土梁刚度计算的3种计算模式.

Eight high-strength concrete beams in four groups with 600MPa steel bars,C60 concrete strength,and different reinforcement rates were tested.Two compared concrete beams in one group with 400MPa steel bars were also tested to study the rigidity of the beams.The strain variation of concrete along the depth direction under different level loads was determined,and the stress variation of steel bars under the normal service stage after beam cracking was also analyzed.The complete load-deflection curves of beams with 600MPa steel bars were obtained.Experimental results show that,the high-strength concrete beams with 600MPa steel bars have good deformation properties,and the load-deflection curves of beams with 600MPa steel bars show a typical triangular line.Under the same conditions,the ultimate bearing capacity of beams with 600MPa steel bars increased by 41.6%,compared with the beams with 400MPa.On the basis of the experimental results,the applicability of the calculation formulas of domestic and foreign codes for the rigidity of beams with 600MPa steel bars was analyzed.Finally,three calculation models for high-strength concrete beams with 600MPa steel bars are proposed based on the experimental data.