Utilizing Secant Pile Walls as Retaining Structures and Bridge Abutments

Abstract

This study presents a design solution for a highway underpass beneath a busy main road in Hail city, Saudi Arabia. The traffic intensity within the project area is very high and some buildings are located very close to the highway. An initial design suggested by the ministry of transportation (MOT, Saudi Arabia) included a sheet pile system and retaining wall abutments. The geotechnical investigation conducted for the site revealed that layers of sandy soils will require the use of sheet piles to prevent loss of lateral support or damage to the foundations of the adjacent buildings and service roads. This study suggested the use of dual-purpose secant piles walls capable of supporting the subsurface soil and provides fewer disturbances to traffic flow during the construction phase. The spread footing and 13.5 m retaining wall design suggested as a first solution was found more expensive and takes longer period of construction. Details of the secant pile walls procedure are given and compared to the conventional retaining wall and sheet pile solution. Cost comparison and elements of choice were highlighted and provided in more details.