| Title |
An Analytical Study of the Strengthening Effect of Reinforced Concrete Beam with High Tension Bars |
| Authors |
Lee Swoo-Heon ; Kim Byung-Jun ; Park Min-Suk ; Shin Kyung-Jae |
| Keywords |
Shear Strength ; Reinforced Concrete ; High Tension Bars ; External Pretension Reinforcement ; Geometrical Analysis |
| Abstract |
The objective of this study is to develop equations or the method that can predict the strengthening effect on shear capacity of RC beams with high tension bars. The shear capacity of these beams is defined as summation of shear force by concrete, stirrup and high tension bars. To estimate the shear force by concrete and stirrup, Zsutty equation is used. As like other paper, the Zsutty shear equation produces satisfactory predictions as compared to ACI code equation. And the strengthening effect on shear capacity is achieved through the geometrical method. The basic concept of this method is that externally unbonded high tension bars are converted to a vertical component which affects the shear capacity. This geometrical equation contains three parameters such as the area, inclined angle and specified yield strength of high tension bars. Especially, the high tension bars of experimental specimens in this paper didn`t reach the yield point. Therefore it is necessary to estimate the stress of high tension bars at nominal flexural strength for more exact predicting results. There are two ways to estimate this stress; the flexural design code equations of prestressed concrete in ACI 318-05 and the relation equations between load and deflection. In flexural design code, experimental result of theoretical result is about 0.56～0.62. On the other hand, the relation equations betweem load and deflection show that experimental result of theoretical result is about 0.96～1.01 agreement. This paper presents equations to estimate the stress in high tension bars at nominal flexural strength. From the comparison of experimental and predicted shear capacity, an exact agreement is achieved in proposed method. |