问题 单项选择题

下列桥梁承载结构施工方法中,投入施工设备和施工用钢量相对较少的是( )。

A.转体施工法
B.顶推法施工
C.移动模架逐孔施工法
D.提升与浮运施工

答案

参考答案:A

解析: 桥梁承载结构的施工方法包括:支架现浇法、预制安装法、悬臂施工法、转体施工法、顶推法施工、移动模架逐孔施工法、横移法施工和提升与浮运施工。其中,转体施工法的特点是:①可以利用地形,方便预制构件。②施工期间不断航,不影响桥下交通,并可在跨越通车线路上进行桥梁施工。③施工设备少,装置简单,容易制作并便于掌握。④节省木材,节省施工用料。采用转体施工与缆索无支架施工比较,可节省木材80%,节省施工用钢60%。⑤减少高空作业,施工工序简单,施工迅速,当主要结构先期合拢后,给以后施工带来方便。⑥转体施工适合于单跨和三跨桥梁,可在深水、峡谷中建桥采用,同时也适应在平原区以及用于城市跨线桥。⑦大跨径桥梁采用转体施工将会取得良好的技术经济效益,转体重量轻型化,多种工艺综合利用,是大跨及特大路桥施工有力的竞争方案。

单项选择题
阅读理解

阅读理解。

     Running, as most of you already know, is a sport that all sorts of people love. Running a marathon is also

something that many long-distance runners have as a goal. Now if you decide you want to train for a marathon,

how do you go about getting yourself into excellent shape for the race of your life? 

     Most marathon training schedules last around 20 weeks and are designed for runners who can run 4-5 days

per week. The secret of a successful training schedule lies in avoiding injury that can happen through pushing

yourself too fast or too hard. So, the idea is to increase your mileage gradually from, let's say,20 miles per week

up to runs of 50 miles per week at some point before the actual marathon. Alternate (交替) hard days with easy

days: an easy day could be a day off altogether or something else like a three-mile run which, although it might

not seem to be really worth the effort to some of you, actually is a joy to do.

     Be careful how you warm up and slow down, because these are the times when injuries could happen. When

you set off for a run, take the first mile slowly and when you break into a sweat, stop and do some stretching

exercises for a couple of minutes. Always take the last mile slowly too-if you stop suddenly after a hard run,

then those of you who might have heart attacks are putting yourselves at greater risk at the point. One word of

warning: don't start a training schedule without some guidance from a properly qualified trainer. He or she will

be able to tell you what you're doing right or wrong! Remember that under normal circumstances, health

benefits from regular running are an increased sense of energy and well being, together with fitness.

1. In the second paragraph, the writer says that _____. [ ]

A. it's not worth doing a three-mile run

B. there should be some easy days rather than hard days

C. the training period should last for three weeks

D. a short run can be a pleasant experience

2. The most dangerous times are when you are _____. [ ]

A. starting and stopping

B. building up speed

C. running hard

D. sweating a lot

3. This article might be written for _____. [ ]

A. people interested in taking up running

B. young athletes

C. people already involved in running

D. athletics trainers

4. If you run on a regular basis, you will _____.[ ]

A. avoid having heart attacks

B. be able to win a marathon

C. feel better and more energetic

D. become a faster runner