Title: Tension Stiffening Model for Steel Fiber-Reinforced Concrete Members
Author(s): C.-W. Hong, K.-K. Yun, B.-H. Lee, and J.-H. Lee
Publication: Symposium Paper
Appears on pages(s): 259-274
Keywords: cracking; fiber-reinforced concrete; tension stiffening
This paper presents results of an investigation into the tension stiffening effects of steel fiber reinforced concrete members in direct tension. Tension stiffening effects and losses of strain energy were analyzed from the load-defl .ection curves with the main experimental variables such as concrete strength, steel fiber content, and concrete cover depth. Tension stiffening effect of RC members increases linearly until first crack, decreases inversely with number of cracks, and then decrease rapidly when splitting cracks occur. The higher the content of steel fiber the higher tension the stiffening due to its bridging effect after cracking inside of member. Therefore, it is necessary to consider the tension stiffening effects with a nonlinear analysis. From the comparison between the results of experiment and existing models, it is found that the existing models could not incorporate the effects of concrete strength, cover depth and fiber reinforcement. Thus, it is required to develope a new model which could include these factors. This study proposes a new model which is defined by tension stiffening factor by considering concrete strength. and the ratio of cover depth with al and a2, respectively. The tension stiffening model for steel fiber reinforced concrete is, also, proposed as a shape of u-i-bilinear, considering concrete cover. depth. The analysis using the proposed model shows good agreement with that of experiment on direct tension and flexural members at all concrete strength levels.