问题 单项选择题

若抗震设防烈度为8度的框架首层顶的梁柱中间节点,横向左侧梁截面尺寸为300mm×800mm,右侧梁截面尺寸为300mm×600mm,纵向梁截面尺寸均为300mm×700mm,其as均为60mm,该框架抗震等级为二级,柱截面尺寸为600mm×600mm。节点左侧梁端逆时针方向组合弯矩设计值=430.52kN·m,右侧梁端逆时针方向组合弯矩设计值=239.48kN·m,节点上下柱反弯点之间的距离为4.65m。则此情况下计算节点的剪力设计值Vj与下列哪项最接近().

A.1476.48kN

B.1330.50kN

C.1182.66kN

D.973.52kN

答案

参考答案:C

解析:

根据《混凝土规范》第11.6.2条式(11.6.2-4)计算,因节点左右侧梁高度截面不等,按规定取平均值,即hb=(800+600)/2=700mm,=60mm,hb0=700-60=640mm。柱的计算高度可取节点上下柱反弯点之间的距离,即Hc=4.65m。

框架抗震等级为二级,取ηjb=1.2,ΣMb=430.52+239.48kN·m。

根据《混凝土规范》式(11.6.2-4),中柱节点的剪力设计值为:

Vj=1.2×(430.52+239.48)/(0.64-0.06)×[1-(0.64-0.06)/(4.65-0.70)]

=1182.66kN

误取梁截面的有效高度为600mm,故A错;框架抗震等级为二级,误取ηjb=1.35故B错;误取梁截面的有效高度为800mm,故D错。

[点评] (1)抗震设计时,一、二、三级框架的节点核心区应进行抗震验算;四级框架节点可不进行抗震验算。

(2)各抗震等级的框架节点均应符合构造措施的要求。即:箍筋的最大间距和最小直径宜符合《高规》第6.3.7条有关柱箍筋的规定。一、二、三级框架节点核心区配箍特征值分别不宜小于0.12、0.10和0.08,且箍筋体积配箍率分别不宜小于0.6%、0.5%和0.4%。柱剪跨比不大于2的框架节点核心区配箍特征值不宜小于核心区上、下柱端配箍特征值中的较大值。

阅读理解

阅读短文,翻译画线句子。

     "Be proud of what you do," my father always told me, "whether you are a boss or a cleaner." 1 当我15岁时, I got a summer job in a hospital. I was told that my duties would include sweeping floors, washing dishes and

cleaning toilets. I smiled and remembered dad's words."

     Even though my job was the lowest, 2 It made me feel excited. I regarded it as a challenge 3 因为它是

我的第一份工作. I learned to be on time and tried to do everything well. In return, I was treated with respect

by doctors, nurses, and patients. Each morning I imagined that the dirty dishes would make patients more sick

if I were not there to wash them clean. After breakfast was done, I started sweeping the floors of all patients'

rooms and cleaning toilets. Though I was tired, I wanted my job to be done well. People would say, 4 "That

young man can always do everything well."

      Working in the hospital taught me that being proud of one's job is very important. I have swept the floors,

and I have been a manager."Be proud of what you do." 5 my father's words have deeply influenced me all my

life. And I'm sure dad must be proud of me.

1._____________________________________________________________

2._____________________________________________________________

3._____________________________________________________________

4._____________________________________________________________

5._____________________________________________________________

单项选择题