Continuing education

Abstract

Driven by increase in trend of construction two storey house in the community, more bamboo and wood are needed to construct formwork in the traditional concreting method. The present of waste from the discarded wooden formwork make the construction method is an inefficient and environmentally unfriendly. A semi-precast method offers a more economical method of construction owing to its less use of bamboo/wood in slab concreting process. This study is intended to characterize the dynamic behavior of semi-precast slab. There were 5 full scale slab specimens cast for this research. One specimen was monolith slab that acts as a control specimen. While the other 4 specimens were made with various shear connector arrangements. On each slab specimens, the dynamic testing was firstly proceeded. The dynamic testing was conducted to determine the dynamic characteristics, displacement mode, mode curvature and absolute difference of curvature mode of slab. The static test was carried out when the dynamic was completed to determine the ultimate capacity as well as collapse pattern of slab being tested. The results showed that there were differences in natural frequency for each slabs, either monolithic or semi-precast slabs. Monolith slab has natural frequency of 14.84 Hz, while semi-precast slab without shear connector has natural frequency of 13.45 Hz. Semi-precast slab with shear connector spacing of L/4(100) - L/2(150) - L/4(100), L/3(100) - L/3(150) - L/3(100) and 100 mm have natural frequency of 13.62 Hz, 13.46 Hz and 15.97 Hz. Displacement mode of monolith slab is smaller than that of semi-precast slab. These test results show that semi-precast slab has a slightly lower stiffness than monolith slab, but it has the same strength characteristics. An indication of similarity was also found between the characteristic of absolute difference of curvature mode and the crack pattern occur in slab that suggest the potential use of absolute difference of curvature mode to predict crack pattern in concrete structural members. In general, the results showed that semi-precast slab has similar structural characteristics to monolithic plates.