COST-BENEFIT ANALYSIS OF BI-DIRECTIONAL LOAD TESTING FOR DRILLED SHAFTS AND PERFORMANCE OF ADVANCING CIVIL INFRASTRUCTURE PRACTICE IN THE UNITED STATES

The advancement of civil infrastructure practice increasingly relies on reliable foundation testing methods to ensure structural safety and cost efficiency. This study examines the cost-benefit analysis of bi-directional load testing for drilled shafts and its impact on advancing civil infrastructure practice in the United States. The specific objectives include: (i) investigating the effect of Osterberg Cell (O-Cell) bi-directional load test placement on technical and structural performance, and (ii) analysing the impact of AFT (Applied Foundations Testing)-Cell bi-directional static load test arrangement on economic and operational performance. A quantitative research design was adopted, and 20 drilled shaft test data were analysed using descriptive statistics, independent samples t-tests, and benefit-cost analysis with SPSS version 25. Findings indicated that AFT-Cell significantly reduced settlement (p = 0.02) while both methods provided comparable maximum load capacity. Economically, AFT-Cell yielded higher net benefits and time savings (BCR = 1.50) compared to O-Cell (BCR = 1.40). The study concludes that AFT-Cell offers superior technical reliability and marginally higher operational value. It recommends prioritizing AFT-Cell for critical projects while considering O-Cell where budget constraints exist.