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In this research, the effect of using steel fiber and polypropylene on the behavior of the lightweight self-compacting concrete (LWSCC) beams have been studied. Seven beams have been cast with different parameters and compared. Two ratios of coarse aggregate replacement with light-weight aggregate expanded clay (LECA) have been considered partially and full replacement (50% and 100%) in this study based on previous study. Also, a 1% volumetric ratio fiber reinforcement has been added to investigate its effect on the flexural performance of LWSCC. A reduction in the ultimate load capacity and stiffness have been observed for LWSCC beams compared with the control beam by about 19% and 24.8% for partial and full LECA replacement, respectively. The steel fiber enhanced the performance of LWSCC beams in terms of cracking formation, crack width, ultimate capacity and allow the beams to have more ductile behavior. The ultimate load for fibrous LWSCC has been increased by about 11% and 12% for partial and full LECA replacement compared to beams without fibers. Beams with polypropylene and steel fibers exhibit similar behavior to the beams with steel fiber only in term of load-vertical displacement curves. However, the difference in the ultimate load capacity were 4% and 5% for the partial and full LECA replacement, respectively.

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.