12m跨度的简支钢梁，其截面如图所示，承受均布静力荷载设计值q=80kN/m，假设梁截面由抗弯强度控制。钢材用Q235-B，E43型焊条、手工焊。
若拟对梁腹板在跨度方向离支座x处做翼缘和腹板的拼接对接焊缝，焊缝质量等级三级，试问，根据焊缝强度，确定焊缝位置x（m），与下列何项数值最为接近（）.
A．2.97
B．2.78
C．2.8
D．3.18
参考答案：A
解析：
解答如下：
三级对接焊缝，查《钢结构设计规范》表3.4.1-3，取
按对接焊缝抗弯刚度要求，该处梁截面所能承受的边缘纤维弯曲拉应力为：
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| Every day after breakfast, my mother would go to read the paper and my father would wear that old apron(围裙). For the next hour __1__ would do the dishes, singing songs. I thought it was strange for a boy's father to wear an apron, especially for my hero. I thought it was a __2__ work. But from last Sunday, the tradition ended. "Tommy, it's time for you to take a greater role(角色) in the __3__. Starting today, I want you to do the dishes." The news made me unhappy. My favorite breakfast seemed __4__. Then, my father said to my mother, "Let's go to read the paper together." "Won't you do the dishes?" my mother asked. "Our son would be glad to do that every __5__ from now on." But I __6__ didn't like doing housework. Just when I had decided not to do it, my father came into the kitchen. In his right hand was the old apron. "It'll keep your clothes __7__ getting wet." And __8__ I could protest(抗议), he had put the thing on me. "Thanks, son. Your mother and I appreciate(感激)this." I looked __9__ at the dishes. I could see my dad washing them. Soon I began to __10_ as my father did. Then I knew the kind of man I wanted to be. | |||
| ( )1. A. she ( )2. A. man's ( )3. A. family ( )4. A. delicious ( )5. A. morning ( )6. A. truly ( )7. A. to ( )8. A. after ( )9. A. up ( )10. A. read | B. he B. dirty B. school B. dry B. noon B. even B. out of B. before B. down B. think | C. I C. woman's C. office C. clean C. afternoon C. really C. from C. when C. forward C. sing | D. we D. fun D. world D. terrible D. night D. only D. by D. until D. out D. play |