问题 问答题 简答题

对高层建筑结构进行竖向荷载作用下的内力计算时,是否要考虑活荷载的不利布置?

答案

参考答案:

对高层建筑,在计算活荷载产生的内力时,可不考虑活荷载的最不利布置。

这是因为目前我国钢筋混凝土高层建筑单位面积的重量大约为12~14kN/m2(框架、框架—剪力墙结构体系)和14~16kN/m2(剪力墙、简体结构体系),而其中活荷载平均值约为2.0kN/m2左右,仅占全部竖向荷载15%左右,所以楼面活荷载的最不利布置对内力产生的影响较小。

另一方面,高层建筑的层数和跨数都很多,不利布置方式繁多,难以一一计算。

为简化计算,可按活荷载满布进行计算,然后将梁跨中弯矩乘以1.1—1.2的放大系数。

阅读理解

The Clockwork Radio

The British inventor Trevor Baylis created this really clever ′wind-up radio′ for people from Third World countries. in some parts of the Third World countries, it’s very hard for people to get or pay for enough energy. This radio uses no batteries (电池) and does not need any electricity to run it. A clockwork generator (发电机) is put inside the radio and works as the power. When it is fully wound up (上弦), the radio can work for long periods.

The clock work product is not a new invention. The Victorians had already put it in wide use. We may find them used in toys as well. Then what is new about this clockwork radio? Baylis has used this simple but effective (高效的) way of creating electricity to both help the people of the Third World and to develop a product which is selling well in Western Europe.

Even former President of South Africa, Nelson Mandella has one of these radios and personally recommends this product to others.

小题1:What does the clockwork radio use to run it?

A.Batteries.

B.Electricity.

C.A clockwork generator.

D.Wind power.小题2:The Third World countries are       in the world.

A.the rich countries

B.the poor countries

C.Western European

D.Victorian countries小题3:Which sentence is true according to the passage?

A.the clockwork radio can work for only a short period of time.

B.Trevor Baylis created the world’s first clockwork product.

C.The clockwise radio is also a toy for people of the Third World.

D.Nelson Mandella owns one of the clockwork radios.

单项选择题