Evaluation and rehabilitation of concrete pier

This paper presents a case study of repair and strengthening work carried out on a defective reinforced concrete pier. The pier manifested severe cracking and spalling at the joint between its walls and platform. The distress was due to twisting of the platform as a result of torsional stress, which had also caused diagonal shear cracks to appear on the walls. A comprehensive investigation was carried out in order to determine the causes and extent of the problem and to define the remedial measures needed to rectify the problem and prevent future deterioration. The investigation included three phases: field investigation, which included soil borings, platform temperature measurement, and measurement of twist and tilt of the platform; laboratory investigation, which included soil testing and concrete core testing; and analysis of the structure. The repair work consisted mainly of providing a silica-fume-blended cement shotcrete jacketing system around the structure. The repair work was successful, economical, technically feasible, and not very labor-intensive.