单项选择题
已知一钢筋混凝土偏心受压柱截面尺寸b×h=400mm×500mm,柱子的计算长度10=4000mm,混凝土强度等级为C30,纵向钢筋HRB400,as=40mm。
A.135mm B.298mm C.193mm D.158mm
A.αM=0.450,ηn=1.250 B.αM=0.432,ηn=1.430 C.αM=0.406,ηn=1.430 D.αM=0.485,ηn=1.336
A.75 B.86 C.98 D.106