Job Description: A developer in North Royalton, Ohio was constructing a new residential street in a new phase of their subdivision. The cul-de-sac at the end of the street was surrounded by steep slopes and delineated wetlands at the toe of the slopes. Since the wetlands could not be disturbed, a retaining wall was deemed necessary adjacent to the cul-de-sac to protect the slope. Heartland Design Group, Inc. was contacted to design and construct a curved retaining wall adjacent to the cul-de-sac. Access was limited in front of the retaining wall for installing equipment.
Analysis and Design: In designing the retaining wall, it was determined that helical screw tiebacks was the most cost-effective and feasible method for resisting the overturning loads of the backfill behind the wall. The 1-1/2" solid steel shaft helical screw pile with three helices (8", 10", and 12" diameter) on the lead section was chosen based on the estimated loads and soil conditions. The tiebacks were to be terminated with threadbar adapters, threadbar, galvanized bearing plate, bearing and wedge washers, and anchor nut.
Installation: (9) SS5 tiebacks were installed to an average length of 25 feet with a Bobcat Mini-Excavator. After the cast-in-place concrete retaining wall was constructed and sufficiently cured, the threadbar adapters, threadbar, and associated components were installed and the wall was backfilled.
Installing the tiebacks.
Making tieback connections after construction of wall.