1.(案例题)【背景资料】某钢筋混凝土简支梁,截面尺寸b×h=250mm×700mm,计算跨度L0=7m9、钢筋混凝土梁截面抗弯刚度随荷载的增加及持续时间增加而( )。

A.141.46N/mm2

B.158.62N/mm2

C.174.45N/mm2

D.196.83N/mm2

A.<p><img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705394556594875.png" title="1705394556594078278.png" alt="image.png"/></p>

B.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705385156930867.png">

C.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705385156953353.png">

D.<img src="https://cg-service.oss-cn-shanghai.aliyuncs.com/20240116/1705385156997213.png">

A.101.25kN·m

B.124.63kN·m

C.140.88kN·m

D.163.18kN·m

A.165mm

B.177mm

C.184mm

D.198mm

A.0.0912mm

B.0.137mm

C.0.176mm

D.0.225mm

A.7.91mm，满足要求

B.12.54mm，满足要求

C.17.50mm，满足要求

D.24.82mm，不满足要求

A.采用高强度等级的钢筋

B.采用细直径的钢筋替代粗直径的钢筋

C.增加受力钢筋的有效配筋率

D.增大受拉钢筋保护层厚度

E.采用预应力混凝土

A.平均刚度原则

B.实际刚度原则

C.最小刚度原则

D.最大刚度原则