Papers by Author: Jin Song Lei

Abstract: Based on the Unified Strength Theory(UST),the ultimate load calculation formula for the recycled aggregate concrete-filled steel tubular short columns is derived in this paper,in which the decrease of longitudinal stress because of the hoop tensile tension is considered. The influence of intermediate principal stress on the ultimate load is studied and the failure mechanism is also discussed. The results show that the intermediate principal stress have important effect on the ultimate load which increases with the strength parameter .Through the comparison between the experimental results and the calculating results obtained in this paper,the deviation is small,and it shows that the formula have significance in exerting material potential.

Abstract: In this paper, the influence of temperature on the cracking of reinforced concrete frame is studied. Finite element analysis software is used to simulate the concrete cracking. In the modeling process, separate model element of SOLID65+LINK8 is used. Also, the Hongestad model is applied to the stress-strain relation of concrete and the rule of BISO is applied to the stress-strain relation of steel. By comparing the stress and strain of three different structure frames before and after temperature increasing, the extending rules of concrete cracking and the stress character of beam and column are analyzed. It is found that the maximum stress of beam is located in the end of the beam-column joints and the middle of beam under the temperature action. It is suggested that they are caused by moment and axis-force respectively. However, the greatest stress of column is situated at the end of beam-column joints. The reason is that the end of beam-column joints should deform to coordinate the influence of temperature. Thus, greater peak stress is caused. So, the concrete cracking is always distributed in the middle of beam span or beam-column joints, where the position of stress concentrates. In addition, the stress of steel in beams increases greatly under the temperature load, suggesting that the temperature leads to the internal force redistribution in the concrete component and the cracking of component.