1.(案例题) [背景资料]已知一T形截面独立梁需承受弯矩M = 650kN·m ,混凝土强度等级为C30,钢筋采用HRB400级,T形梁截面尺寸 b×h=300mm×700mm, ；环境类别中为-类。(按单筋截面考虑)请根据背景资料完成相应小题选项,中单选题四选一(A、B、C、D选项),多选题五选二 或三或四(A、B、C、D、E选项)；不选、多选、少选、错选均不得分。8、若本案例中的弯矩降低到 550kN·m,按《混凝士结构设计规范》GB 50010-2010 (2015年版)算得的等效受压区高度为( )。

A.0.01

B.0.002

C.0.0025

D.0.0033

A.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384181035559.png">

B.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384181053404.png">

C.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384181081187.png">

D.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384181098481.png">

A.正截面受弯承载力计算

B.斜截面受剪承载力计算

C.构件变形及裂缝宽度验算

D.扭转承载力计算

A.0.01

B.0.002

C.0.0025

D.0.0033

A.0.614

B.0.550

C.0.518

D.0.508

A.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384180856563.png">

B.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384180915885.png">

C.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384180943861.png">

D.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705384180960409.png">

A.0.2%

B.45ft/fy

C.0.2%和45ft/fy的最大值

D.0.2%和45ft/fy的最小值

A.11.9N/m2

B.14.3N/m2

C.16.7N/m2

D.19.1N/m2