配置高强钢筋的混凝土梁裂缝试验研究

采用两点对称集中的同步分级加载方式，对8根配置500MPa钢筋和4根配置400MPa细晶钢筋的混凝土梁进行静力加载试验，观测试件的裂缝发展过程，了解此类构件的裂缝特点，为工程中推广应用500MPa钢筋和400MPa细晶钢筋提供试验依据。试验结果表明，配置500MPa钢筋和400MPa细晶钢筋的受弯构件裂缝发展规律与普通钢筋混凝土受弯构件基本相同，但在正常使用状态下，按照现行混凝土结构设计规范对此类构件进行裂缝宽度验算，计算值均大于试验值。同时，结合其它67根配置高强钢筋的混凝土梁试验数据，评估了现行混凝土结构设计规范裂缝宽度公式的适用性，并在该规范的计算模式基础上，提出平均裂缝间距及短期最大裂缝宽度计算的修正公式，修正公式的计算结果与试验结果符合较好。

Experimental Analysis of Cracking Behavior of ConcreteBeams Reinforced with High Strength Bars

Eight concrete beams reinforced with 500MPa steel bars and four reinforced with 400MPa ultra-fine grain steel bars were tested under two-point symmetrical concentrated static loading to observe the details of crack pattern development on these beams and investigate their cracking characteristics. It was shown that the cracking behavior of the beams with high-strength bars was essentially similar to that of common RC flexural members, whereas the computed crack widths using the formula adopted in the Code for Design of Concrete Structures GB 50010-2002 exceeded that of the experiment under the normal service. Furthermore, the formulas for crack spacing and crack width specified in GB 50010-2002 were evaluated through the experimental results and previous studies of sixty-seven concrete beams reinforced with high-strength bars. On the basis of the calculation model in GB 50010-2002, revised formulas for crack spacing and crack width were proposed. The values calculated by revised formulas were in good agreement with the test results.