论文部分内容阅读
在螺纹钢筋用接触对焊以后,其疲劳强度将比整根钢筋的疲劳强度降低20~25%,这样一来往往需要增加钢筋的用量。接触对焊后,钢筋疲劳强度降低的主要原因是:在焊接过程中由于接头处加热、顶锻,使得螺纹钢筋原来的螺纹部分被挤压变形,被挤出的钢料使接头处形成一个不匀顺的过渡,造成高度应力集中,因而在多次重复荷载下容易产生裂缝,并可能发展,以致遭到破坏(图1)。
After thread-reinforced steel is contact-welded, its fatigue strength will be reduced by 20-25% compared with the fatigue strength of the entire steel bar. This will often require increasing the amount of steel reinforcement. After contact butt welding, the main reason for the decrease of the fatigue strength of the steel bars is: during the welding process, due to the heating and upsetting of the joints, the original threaded part of the threaded steel bar is squeezed and deformed, and the extruded steel material forms a gap at the joint. The smooth transition causes high stress concentration, and therefore cracks are likely to occur under multiple repeated loads and may develop so as to be destroyed (Figure 1).