问题 问答题 案例分析题

背景材料:

某高速公路B标段,承建一座10×30m连续箱形梁桥,5跨一联。设计基础为嵌岩桩,桩径1.5m;下部构造为双柱式墩,直径为1.3m,柱顶设置盖梁,墩柱高度为8~18m。施工人员提出如下墩柱施工方案:(1)对已完工的桩基,按要求凿去桩头到设计标高,调直桩头钢筋。(2)墩柱钢筋骨架现场整体制作一与桩头钢筋绑扎焊接,受力主筋直径为22mm的Ⅱ级钢筋,主筋采用对焊工艺,按规定同一截面接头不超过50%,主筋下料长度为墩桩高度+锚人盖梁长度+搭接双面焊缝长度。采用25t吊车(起重臂长30m)整体吊装就位,焊接检查合格后,支撑牢固。(3)墩柱模板采用其他工地使用过的旧钢模,其刚度、拼缝等满足要求。采用整体拼装、涂刷脱模剂后,一次整体吊装就位,再在顶部箍筋四周插入木楔,使钢筋骨架居中,使保护层厚度得到有效控制。(4)按规范要求的工艺浇筑混凝土。

本施工方案中是否有错误、如有请指出并说明理由。

答案

参考答案:

1)主筋下料长度相同,不能满足规范同一截面接头不超过50%的规定。

2)有些墩柱太高,起重臂长度不够,模板不能整体吊装,只能分节段整体拼装就位。

3)只在顶部箍筋四周插入木楔,不能有效控制钢筋保护层厚度,应按要求系好保护层垫块。

选择题
阅读理解

  Trees are useful to man in three very important ways: they provide him with wood and other products, they give him shade, and they help to prevent drought and floods.

  Unfortunately, in many parts of the world man has not realized that the third of these services is the most important. In his eagerness to draw quick profit from the trees, he has cut them down in large numbers, only to find that without them he has lost the best friends he had.

  Two thousand years ago a rich and powerful country cut down its trees to build warships, with which to gain itself an empire. It gained the empire but, without its trees, its soil became hard and poor. When the empire fell to pieces, the country found itself faced by floods and starvation.

  Even though a government realizes the importance of a plentiful supply of trees, it is difficult for it to persuade the villager to see this. The villager wants wood to cook his food with, and he can earn money by making charcoal or selling wood to the townsman. He is usually too lazy or too careless to plant and look after trees. So unless the government has a good system of control, or can educate the people, the forests will slowly disappear.

  This does not only mean that the villagers sons and grandsons have fewer trees. The results are even more serious. For where there are trees their roots break the soil up—allowing the rain to sink in and also hold the soil, thus preventing it being washed away easily, but where there are no trees, the soil becomes hard and poor. The rain falls on hard ground and flows away on the surface, causing floods and carrying away with it the rich topsoil, in which crops grow so well. When all the topsoil is gone, nothing remains but a worthless desert.

63. The purpose that the writer wrote this article for is ____ .

 A. to tell people that trees are very useful to man

 B. to warn people not to cut down trees any more

 C. to warn that man mustn't destroy forests any more

 D. to explain how trees help to prevent drought and floods

64. In the writer's opinion, ____ , or the forests slowly disappear.

 A. measure must be taken                      B. people shouldn't draw benefit from the tree

 C. government must realize the serious results      D. unless trees never be cut down

65. According to the article we know it is ____ to prevent the forests from slowly disappearing.

 A. necessary but impossible                    B. necessary but difficult

 C. impossible and unimportant                  D. difficult and impossible

66. In the last two paragraphs the writer wanted to make it clear that ____ .

 A. where there are no trees, the soil becomes hard and poor

 B. where there are many trees, there are fewer floods

 C. where there are no trees, the land might become desert slowly

 D. floods will make the land become desert