混凝土板的负筋在施工中,如果不注意而被压低,会使板的承载力大大降低,出现质量事故。那么,它的危害程度究竞有多大?下面举例来说明这个问题。例,有一现浇板,其混凝土强度等级为C20,板厚100衄,负筋配置φ10@140(取板宽为lm计,A,=561mm~2),此板负筋在施工中不慎被压低20mm,试验算该板承裁力降低多少? The negative reinforcement of the concrete slab is under construction. If it is pressed down without paying attention, the bearing capacity of the slab will be greatly reduced and quality accidents will occur. So, how much harm does it have to pay? Here are some examples to illustrate this issue. For example, there is a cast-in-place slab, the concrete strength grade is C20, the slab thickness is 100 衄, and the negative rib configuration is φ10@140 (taken by a plate width of lm, A,=561 mm~2). The negative ribs of this plate are careless during construction. It is pressed down by 20mm. How much does the test result reduce?