| Title |
Field Application and Monitoring of Delay Joints to Reduce Shrinkage Cracks |
| Authors |
Lee Myung-Ho ; Sho Kwang-Ho ; Park Hyung-Cheol |
| Keywords |
Delay Joint ; Underground Parking Lot ; Crack ; Beam Reinforcement ; Slab Reinforcement ; Monitoring |
| Abstract |
Delay joints are useful to reduce shrinkage cracks to allow a significant part of the shrinkage to take without inducing stresses. Recently, delay joints have been used in slabs of underground parking lots. Mark Fintel proposed that delay joint is usually 60 to 90cm wide across the entire building. Development length of HD13 for longitudinal reinforcement of slab is about 60cm, but, development length of HD25 for longitudinal reinforcement of beam is about 220cm. So, different development lengths between slab and beam make difficult to construct the delay joint. In this paper delay joints are constructed to have same width in slab and beam regions uncutting reinforcements in beam region. Also, to confirm the possibility to construct delay joint uncutting the longitudinal reinforcement of beam, behavior of restrained beam reinforcement in regions of delay joint was monitored using total eighteen measuring instruments (strain gauges, LVDTs, thermo couple and so on). Lastly effect of delay joint was investigated through the assessment of occurred slab crack. |