对桁架结构的假定有以下哪些?()
A. 节点都是铰接
B. 每个杆件的轴线是直线,并通过铰心
C. 杆件受轴力和弯矩作用
D. 荷载及支座反力都作用在节点上
E. 杆件受轴力、剪力和弯矩的作用。
静定平面桁架的内力计算方法有()
A. 节点法
B. 截面法
C. 联合法
D. 叠加法
E. 微分关系法
计算多跨静定梁时,必须先从基本部分计算,再计算附属部分。()
A. 对
B. 错
Fill in the blanks with the expressions given below.Change the form where necessary. Each expression can be used only once.have a say onmake a racketrun errandsextract...fromcater toscrape bybe destined toemancipate... from1 The amount of oil capable of________the earth is ever decreasing, and we will be officially running out of oil some day.