HRB600级钢筋混凝土梁受弯性能试验研究

Experimental study on flexural performance of concrete beams with HRB600 steel bars

为研究配置HRB600级钢筋混凝土梁的抗弯性能,文章设计制作12根不同配筋率的HRB600级钢筋、C50混凝土梁,采用三分点静力加载的方式,对试件的破坏形态、钢筋强度设计值取值、极限承载力、跨中挠度及裂缝宽度等进行试验研究。结果表明,配置HRB600级钢筋混凝土梁的受力形态、破坏模式与普通钢筋混凝土梁相同,其极限承载力仍然可以按照相关规范公式进行计算;建议对于受弯构件,HRB600级钢筋的屈服强度标准值取600 MPa,抗拉强度设计值取520 MPa,抗压强度设计值取435 MPa;对比跨中挠度实测值与相关规范计算值,发现两者在正常使用阶段吻合良好;试件实测最大裂缝宽度值比相关规范计算值大,在此结果基础上提出最大裂缝宽度调整系数k,对短期荷载作用下最大裂缝宽度计算公式进行修正,调整后得到的计算值与实测值吻合度较高。

In order to study the flexural performance of concrete beams with HRB600 steel bars,twelve concrete beams with HRB600 steel bars and C50 concrete under different reinforcement ratios were designed and fabricated.Experimental study on the damage modes,design value for steel bar strength,ultimate bearing capacity,midspan deflection and crack width of the members was conducted by means of three-point static loading.The results show that the force patterns and damage modes of concrete beams with HRB600 steel bars are the same as those of the concrete beams with ordinary rebar,and their ultimate bearing capacity can still be calculated according to the relevant code formula.It is recommended that for flexural members,the standard value for yield strength of HRB600 steel bars is 600 MPa,design value for tensile strength is 520 MPa and design value for compressive strength is 435 MPa.Comparing the measured values of mid-span deflection with the calculated values in the relevant code,there is a good agreement between the two values in the normal use phase.The measured maximum crack width values of the members are larger than the calculated values in the relevant code,and on the basis of this result,the adjustment coefficient k of maximum crack width is proposed,and the formula for calculating maximum crack width under short-term load in the code is modified.The calculated values obtained after adjustment are in good agreement with the measured values.