Helical Tiebacks Installed for First Business Center in Appleton, WI

Challenge

The First Business Center building located on the corner of Hwy 41 and Hwy BB was being sold. The title work showed a portion of the property encroached on Hwy 41’s right of way. The owner negotiated with the State to deed over a strip of land along Hwy BB in exchange for the portion being encroached. The State also required a new 167 foot long retaining wall to be constructed for potential expansion of Hwy BB. The engineer designed a poured concrete retaining wall be constructed to allow the sloping grade to be leveled out. The wall required nine helical tiebacks to be installed to prevent tipping of the wall. The face of the wall would be formed and later stained to create a faux stone appearance. This required an integral waler system to be incorporated inside the wall.The engineer specified a minimum embedment length of 20’ to achieve a 15 kip allowable capacity.

Solution

Since the face of the wall was to be a faux stone the Foundation Supportworks anchor plates would need to be installed inside the wall. This required the nine helical tiebacks be installed prior to construction of the wall. Once the tiebacks were in place the concrete contractor wire tied the anchor plates inside the wall and used 4 inch corrugated pipe to create a hole to allow the thread bar and nuts to be installed. Once the forms were removed and prior to backfilling the thread bar was installed and tightened. After the wall was back filled the anchors were pre-tensioned to pull out the coupler slack and mobilize the soil strength. The excess thread rod was torched off and the holes were filled with concrete to allow for staining of the wall when weather permitted. The nine tiebacks were installed in two days.

Project Summary

Structural Engineer: Larson Engineering Inc.

Certified Installer: Foundation Supportworks of WI

Products Installed: (9) Foundation Supportworks Model 150 Helical Tiebacks