An overview of punching shear phenomena in reinforced concrete flat slabs
List of Authors
  • Chao-Dong Woo , Jeffrey C L Chiang

Keyword
  • Punching shear, flat slabs, reinforced concrete, column, reinforcement

Abstract
  • Punching shear failure could occur in a flat slab column connection in cases of overloads of the slab or due to improper design of column-slab joints. Past incidents showed that accidents that happened due to punching shear failure of flat slabs had resulted in numerous casualties of building occupants. Over the years, many researchers have undertaken various research studies on the behaviour structures in response to punching shear phenomena in reinforced concrete flat slabs. In this Final Year research project paper, some data of the studies were be collected to identify any new developments on the design and analysis of punching shear strength of reinforced concrete flat slabs. In addition to that, published experimental data and results from the past researchers on punching shear strength of flat slabs are collated to compare the experimental punching shear strength to the predicted results by selected design code provisions (i.e. Eurocode 2, BS 8110 and ACI 318). Besides that, the current provisions in the international standards with regards to punching shear design of flat slabs are compared. It was found out that Eurocode 2 is the most accurate among the three codes to predict the punching shear strength of flat slabs without shear reinforcement. As for flat slabs with shear reinforcement, ACI 318 is most accurate and conservative compared to the other two codes. Partial replacement of cement in concrete using steel fibers can increase the punching shear strength and the ductility of the slab. As for the post tensioning reinforcement of flat slabs, it was concluded that in slabs that were reinforced with two strands of post tensioning strands, the post punching resistance was 78% of the punching shear capacity. In this paper, it is also shown that the method of using inclined bonded bars is effective in post reinforcement for flat slabs.

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