问题 单项选择题

某一设有吊车的钢筋混凝土单层厂房,下柱长He= 11.5m。上下柱的截面尺寸如图2-20所示。截面采用对称配筋,as=a’s=40mm。采用C30的混凝土,纵向钢筋为HRB335,内力组合后的最不利内力设计值,上柱是M=112kN·m,N=236kN;下柱是M= 400kN·m,N=1200kN。

若已知下柱为大偏心受压,截面中和轴通过腹板,轴向压力作用点至纵向受拉钢筋的合力点的距离e=800mm,则下柱截面的一侧纵向受拉钢筋的最小配筋面积最接近于()mm2
提示:计算时不考虑工字形翼缘的斜坡面积,最小配筋面积应在计算配筋面积与按最小配筋率计算的面积中取较大值。

A.305

B.335

C.360

D.410

答案

参考答案:C

解析:

阅读理解

The Healthy Habits Survey(调查)shows that only about one third of American seniors have correct habits. Here are some findings and expert advice.

1. How many times did you brush your teeth yesterday?

·Finding:A full 33% of seniors brush their teeth only once a day.

·Step:Remove the 300 types of bacteria in your mouth each morning with a battery-operated toothbrush. Brush gently for 2 minutes, at least twice a day.

2. How many times did you wash your hands or bathe yesterday?

·Finding:Seniors, on average, bathe fewer than 3 days a week. And nearly 30%wash their hands only 4 times a day-half of the number doctors recommend.

·Step:We touch our faces around 3, 000 times a day-often inviting germs(病菌)to enter our mouth, nose, and eyes. Use toilet paper to avoid touching the door handle. And, most important, wash your hands often with hot running water and soap for 20 seconds.

3. How often do you think about fighting germs?

·Finding:Seniors are not fighting germs as well as they should.

·Step:Be aware of germs. Do you know it is not your toilet but your kitchen sponge(海绵)that can carry more germs than anything else? To kill these germs, keep your sponge in the microwave for 10 seconds.

小题1:What is found out American seniors?

A.Most of then have good habits.

B.Nearly 30%of then bathe three days a week.

C.All of then are fighting germs better than expected.

D.About one third of them brush their teeth only once a day小题2:Doctors suggest that people should wash their hands          .

A.twice a day

B.three times a day

C.four times a day

D.eight times a day小题3:Which of the following is true according to the text ?

A.We should keep from touching our faces.

B.There are less than 300 types of bacteria in the mouth.

C.A kitchen sponge can carry more germs than a toilet.

D.We should wash our hands before touching a door handle.小题4:The text probably comes from            .

A.a guide book

B.a popular magazine

C.a book review

D.an official document

填空题