| Title |
Flexural Behavior and Stress of Unbonded Tendons of Post-Tensioned Lightweight Concrete One-Way Slabs |
| Authors |
Yang Keun-Hyeok ; Mun Ju-Hyun ; Byun Hang-Yong ; Oh Myoung-Ho |
| Keywords |
Post-tension ; Lightweight Concrete ; Flexural Strength ; Stress Increase in Unbonded Tendons ; ACI 318-08 |
| Abstract |
Six post-tensioned lightweight concrete (LWC) one-way slabs were tested under a symmetrical one-point top loading system. According to tendon profile, the specimens were classified into two groups: S-group for slabs with straight tendons and V-groups for slabs with harped (counter-moment shaped) tendons. The span-to-tendon depth ratio() varied to be 15, 35 and 55 in each group. The flexural cracking moment and ultimate moment of one-way slab tested and stress increase measured in unbonded tendons were compared with those of post-tensioned normal-weight concrete (NWC) beams compiled from the comprehensive database and predictions obtained from the design equations specified in the ACI 318-08 provision. Test results showed that the distribution and width of flexural cracks was significantly affected by the , indicating that the larger the , the smaller the crack width. On the other hand, tendon profile had a significant influence on deflection and flexural capacity of one-way slabs, showing a smaller deflection and a higher strength in slabs with harped tendons than in slabs with straight tendons. At the same value of reinforcing inde, the flexural cracking moment and ultimate moment of post-tensioned LWC one-way slabs were pretty comparable to those of post-tensioned NWC beams. In addition, flexural strengths and tendon stress increase of post-tensioned LWC one-way slabs could be conservatively predicted by the ACI 318-08 provision. |