Title:
Punching Shear of Continuous Flat Reinforced Concrete Slabs
Author(s):
N. J. Gardner and Xiao-Yun Shao
Publication:
Structural Journal
Volume:
93
Issue:
2
Appears on pages(s):
219-228
Keywords:
concrete construction; flat concrete slabs; punching shear; reinforced concrete; structural design; Structural Research
DOI:
10.14359/1494
Date:
3/1/1996
Abstract:
This paper presents experimental results for the punching shear of a two-bay-by-two-bay flat reinforced concrete slab. The results show that the interior column slab connection is more critical in punching shear than the edge and corner column connections in a properly designed multibay flat slab. Large flexural cracks indicative of steel yield were evident at all connections where punching shear failures occurred. Supplementary supports can increase punching shear capacity by about 30 percent at edge column connections. An empirical method using a shear perimeter around the loaded area is developed. The code provisions of ACI 318-89, BS 8110-85, and the CEB-FIP 1990 Model Code were recalculated in terms of mean concrete strength using published experimental results to remove their conservatism. Comparison shows that isolated punching tests can represent the punching shear behavior of interior column slab connections in continuous slab systems. All four methods were adequate to predict the capacity of edge and corner column connections under gravity loads. Finally, the code format equations and the proposed equation were recalculated to obtain 95 percent characteristic values.