在钢筋混凝土结构构件施工中,经常会发生材料短缺的情况。然而,工程不能因此而停工。这种情况下,就要采用其它材料进行代换。材料的代换应当既不违反设计的强度要求,又要经济合理。但有些施工负责人员在现场施工中,在材料代换时虽然考虑了强度要求和经济情况,却忽略了代换的材料是否合理。如在钢筋混凝土结构施工中经常有人用Ⅱ、Ⅲ级钢筋代换Ⅰ级钢筋,让Ⅰ级(光面) In the construction of reinforced concrete structural members, material shortages often occur. However, the project cannot be shut down. In this case, other materials will be used for substitution. Substitution of materials should not violate the design strength requirements, but also economic and reasonable. However, some construction personnel in charge of on-site construction did not consider whether the substituted materials were reasonable although they took into account strength requirements and economic conditions during material substitution. For example, in the construction of reinforced concrete structures, people often use Class II and Class III steel bars to replace Class I steel bars, so that Class I (glossy)