Effective Moment of Inertia of Reinforced Concrete Piles

Traditionally, reinforced concrete (RC) piles for earth retaining systems have been designed using symmetrical reinforcement. The non-symmetric or asymmetric RC pile is a recently patented struc-tural element. Savings of up to 50% of longitudinal reinforcing steel can be obtained using non-symmetrically reinforced piles in comparison with traditional symmetrical ones. In this work, the calculation of the short-term deflection of cracked RC piles using the concept of effective moment of inertia is investigated. Five specimens with both symmetric and asymmetric reinforcements were tested in four-point bending tests. In addition, a numerical finite element analysis of symmetric and non-symmetric circular RC members was also carried out to enlarge the available data-base. The widely used expressions of effective moments of inertia proposed by Branson and Bischoff (originally conceived for rect-angular sections) were adapted to fit experimental and numerical results. Both symmetrically and asymmetrically reinforced concrete elements were studied.