Study the ductility of lap joints in reinforced concrete beams to propose a more sustainable design

The Fib Model Code 2010 introduced new design guidelines for tension laps, which have influenced the upcoming version of Eurocode 2 set to be released in 2023. Unlike the previous Eurocode 2 standards, the Model Code 2010 suggests longer lap lengths, potentially resulting in longer lap joints compared to the British Code (BS 8110-1). This study aims to enhance the sustainability of RC frame buildings by exploring the use of shorter lap lengths to reduce steel consumption in concrete structures and subsequently lower CO2 emissions. A comprehensive investigation, involving both experimental and numerical analyses, was conducted to assess the impact of rebar lap joints on the strength and ductility of beams. The experimental phase focused on simply supported reinforced concrete beams with lap splices subjected to four-point bending, varying lap lengths, and two types of reinforcement bars. The findings indicated that increasing the lap splice length enhances the stiffness, resistance, and ductility of the beams. However, extending the lap splices beyond 50∅ did not yield any additional benefits in terms of strength and ductility. It is evident that the current lap length recommendations by Eurocode 2 and Fib Model Code 2010 could potentially compromise the economic and environmental efficiency of construction projects without significantly enhancing the structural performance of the building.