Minimizing cutting wastes of reinforcing steel bars through optimizing lap splicing within reinforced concrete elements

A major waste stream in construction of concrete structures is the steel reinforcement waste generated during cutting of steel rebar to their final required lengths. The amount of steel waste generated during the cutting process can be affected considerably by the cutting patterns specified to steel providers after structural design of reinforced concrete elements. This paper proposes a novel approach for minimizing the cutting waste from reinforcing bars by taking advantage of a slight flexibility in selecting the location of lap splices of reinforcing bars within reinforced concrete members as specified by design codes. The focus is placed on identifying the lap splicing patterns for steel reinforcement used in concrete columns and shear walls. A framework to implement the proposed approach is presented and applied to a case study involving the construction of columns and shear walls for an actual 6 storey building. The estimated waste produced after adoption of optimal lap splicing patterns obtained using the allowable flexibility for the lap splices location is compared with the waste generated when cutting patterns are optimized based on fixed lengths, with no flexibility, according to conventional cutting waste minimization methods. The results show a decrease of 50.7% and 55.7% in terms of steel waste generated, and a reduction of 7.7% and 11.8% in steel reinforcement consumption for columns and shear walls, respectively, due to optimizing the lap splicing patterns by the framework.