Effect of Variation in Physical and Mechanical Properties of Reinforcing Steel on Post-Construction Parameters of Buildings in Nigeria

Abstract

The Nigerian market for construction materials has a problem of standardization as a massive range of variation in construction materials properties plagues the market. A larger number of these variations are below the accepted standards and a key material affected is reinforcing steel. This research aims to investigate the effect of variation in physical and mechanical properties of reinforcing steel on post-construction parameters (cost and safety margins) of buildings in Nigeria. Data on variation of selected properties was collected through extensive literature review and processed into tables showing the result of the input data on key building parameters. Data visualization was done using Microsoft Excel to help gain insights on trends and patterns. The trends and patterns observed informed the regression analysis carried out with Microsoft excel, aimed at establishing relationships between variable variations. A rebar optimization algorithm/software was developed to help optimize variation in standard rebar lengths and reduce waste on site, and was tested on five (5) project cases. The results show a wide range of variation for bar diameter and yield strength values, with some values falling as much as 30% below standard. The variation in young’s modulus was seen to be minimal and has the least effect on safety margins. Equations were generated from regression to predict effect of these variations on safety margins. The rebar optimization algorithm proved efficient in reducing waste and saving cost. The algorithm follows a recursive approach for problem solving. The variation in these properties have a significant effect on building safety and cost. The prediction formulae generated can be used by Engineers to track safety margins and the algorithm can help with waste reduction and cost saving on projects.