关于钢筋混凝土结构受力情况和按极限状态计算方法的研究,在国内外都日益广泛和深入。这些研究的有益成果,自然宜在实际计算中加以考虑。本文不可能探讨所有研究成果,现仅对某些原则性问题加以探讨。直到现在,在规范文件中对混凝土的标号尚没有明确的定义。这指的是,在选择混凝土级配时必需使所得混凝土的强度不低于标号的数值。在引用概率来确定强度特征之后,设计标号的概念就应具 The study on the stress condition and the calculation method of the limit state of the reinforced concrete structure is increasingly widespread and in-depth both at home and abroad. The beneficial results of these studies should naturally be taken into account in practical calculations. It is impossible to discuss all the research results in this paper. Now we only discuss some of the principle issues. Until now, the number of concrete in the specification document has not been clearly defined. This means that when selecting a concrete grading, it is necessary to make the strength of the obtained concrete not lower than the numerical value of the reference. After quoting probability to determine strength characteristics, the concept of design label should be