问题 问答题

无腹筋梁和有腹筋梁的受剪力学模型有什么不同

答案

参考答案:无腹筋梁的受剪力学模型为拉杆拱模型。即,斜裂缝顶部的残余截面为拱顶,拱顶至支座间的混凝土为拱体,纵向钢筋为拉杆,形成拉杆拱模型。
有腹筋梁的受剪力学模型有拱形桁架模型和桁架模型。拱形桁架模型认为,开裂后的混凝土拱体为上弦杆,裂缝间齿块为受压腹杆,箍筋为受拉腹杆。桁架模型认为,斜裂缝出现后的混凝土梁可比拟成铰接桁架:压区混凝土为上弦杆,受拉纵筋为下弦杆,箍筋为竖向拉杆,裂缝间混凝土为斜压杆。

阅读理解

BEIJING—Chinese Premier Wen Jiabao has visited the "left-behind"(留守) children whose parents are working in cities before Children's Day.

During a visit to northwest China's Shanxi Province, Wen visited the home of Yang Saike, a primary school boy in a village of Xingping City. Yang, whose parents were working in Fujian, thousands of kilometers away, was cared for by his grandparents. His parents fail to go home even once a year. Wen talked with many children and asked them many questions about their schooling and life.

"You are so pretty," Wen said to Liu Mengqi, a seven-year-old girl living with her grandmother. Liu's parents were also working in the city.

"Have you been to school yet?" Wen asked two other girls.

"We are going to the pre-school class," said one.

"Mom and dad at home?" Wen asked. The children shook their heads.

"Children cannot see their parents very often, which is a new problem in the country-side. We should give them more care and love," said the premier.

The premier asked local governments to do something to protect and care for such children at home and freeing their parents in cities from worries about their children.

小题1:Wen says a new problem in the country is that "left-behind" children _________.

A.seldom get care from the government

B.seldom get together with their parents

C.cannot do well in school like others.

D.cannot get any love from their parents小题2:Wen Jiabao asks local governments_________.

A.to do more for "left-behind" children and their parents

B.to let the parents see their children only once a year

C.to stop the local people from going to work in cities

D.to build more schools for the "left-behind" children小题3:The proper title (标题) for this passage is "Give ________ more love".

A.poor children

B.disabled children

C.country children

D.'left-behind' children

单项选择题