后张法施工预应力构件时,对单根粗钢筋一段张拉一段固定,固定端可选用的锚具是( )。
A.锥形螺杆锚具
B.螺丝端杆锚具
C.钢制锥形锚具
D.墩头锚具
E.帮条锚具
参考答案:B,D,E
Rising sea levels and drought caused by global warming could an increasing number of natural disasters.
A.try out
B.come about
C.result in
D.get into
容积率是一种既可采用上限控制又可采用下限控制的规划指标。( )