Lauritzen Gardens is one of the most recognized botanical gardens and horticultural conservation sites in the United States. Among the 100-plus-acre facility, one area is dedicated to the display of a replica Japanese garden – including a large stone gate that was donated by the local Japanese community. Over time, the stone-gated entrance to this area of the gardens had settled. At the request of the gate’s donors, the project engineer, Lamp, Rynearson & Associates (Lamp Rynearson), chose Thrasher Commercial Group to assist with lifting and leveling this imposing structure that had settled over one-half inch. The repair work also needed to be completed in time for the garden’s 10-year anniversary celebration.
To permanently halt the settling of the large stone gate, Thrasher Commercial Group used retrofit helical piers to stabilize the gate’s foundation. Using soil composition data provided by Lamp Ryneason, the Thrasher team determined that a total of six (6) Model 288 piers with an 8”-10” helix plate configuration would need to be installed to a depth of approximately 50 feet to find competent bearing soils. The 14,900-pound gate, combined with 103,500 pounds of its concrete foundation measuring 23-foot by 10-foot by 3-foot, would then be properly supported. With input from the Supportworks engineering team, it was determined that a design working load of 25 kips per pier would protect the gate foundation against future settlement. By installing helical piers, the gate was successfully stabilized and re-leveled.