The punching shear strength of reinforced concrete (RC) flat slab is the main concern in the structural behavior. This study presents a strengthening technique for improving punching shear resistance in RC two-way flat slabs using RC column capital. Two sizes of column capital were used (600 × 600 and 800 × 800 mm), and the influence of column capital on the behaviours of two-way solid slabs under concentric and biaxial loading thus investigated. Six specimens were tested, with two slabs as reference specimens with concentric and biaxial loading, and four slabs with added column capital. The dimensions of the slabs were 1,600 × 1,600 × 100 mm, while the column dimensions were 200 × 200 mm. The eccentricity of the biaxially loaded slab was set to 150 mm in both directions. The results showed a considerable increase in punching shear capacity for flat slabs using column capital; further, as the column capital increased, the punching strength of the slab also increased.

This paper presented a strengthening technique for enhancement reinforced concrete (RC) slab-column connection behavior using steel plates and steel stiffeners. A bi-axial load was applied with an eccentricity of 150 mm in both x and z directions. Four specimens with dimensions of 1,600 × 1,600 × 100 mm were tested in this research. The steel plate dimensions were chosen to be 600 × 600 and 800 × 800 mm with 6 mm thickness. The steel stiffeners are used to support and enhance the steel plate that it is extended from column to the slab-column connection with different dimension. The results showed an improvement in the stiffness of slab and increasing in the ultimate capacity. Also, when the steel plates dimensions increased, the ultimate capacity and stiffness increased.