Value engineering using load-cell test data of barrette foundations – La Maison, Dubai

This paper presents a case history of the design, Osterberg load-cell testing, value engineering and revised design by back-analysis of reinforced concrete barrette foundations, resulting in a reduction of barrette length by about 11%, for the 100-storey La Maison tower in Dubai. Rectangular barrettes were selected as an efficient foundation system to transfer 55 MN load per barrette after comparing the design with equivalent-sized circular piles. Bidirectional static load test results were back-analysed using a finite-element model to modify the barrette length. The stiffness parameters were modified after calibrating against the load-cell results, which was matched with a 20% modulus of elasticity from geophysics tests. The relation between unconfined compressive strength and skin friction was back-calculated and compared with commonly used methods in the UAE. Finite-element analysis of a group of barrettes with revised length showed settlement within the limit values. Revising the barrette length by about 11% resulted in significant savings in both cost and construction time.