DYWIDAG Strand Anchors prevent Settlements at a large Retail Center
25 miles south of Birmingham, Alabama, USA, a steep slope located adjacent to a large retail center was reinforced by a Mechanically Stabilized Earth (MSE) Wall. After the completion of the MSE Wall, settlement was detected at the building foundation. The settlement resulted both from the forces applied by the structure above and the instability of the soil both under the building and behind the wall. The foundation of the shopping center settled nearly 90cm (3ft).
The MSE Wall was additionally stabilized using three rows of anchored reaction blocks. These blocks consisted of approx. 3.7m (12ft) square shotcrete leveling pads and precast concrete panels placed against the existing wall. The permanent DYWIDAG Strand Anchors with design loads of approx. 1,779kN (400kips) had to be installed into formations of competent rock deep behind the wall. The anchor length varied from 38m to 61m (125ft to 200ft). DYWIDAG Strand Anchors prevent Settlements at a large Retail Center The DYWIDAG Strand Anchors were loaded against the reaction blocks, thus providing lateral forces that efficiently stabilize the MSE Wall.
One anchor in each row at both ends of the MSE Wall had a single DYNA Force® Sensor installed in its unbonded length. DSI supplied detailed technical literature in addition to the readout box to ensure that the customer was able to self-perform the readings of the 6 DYNA Force® Sensors.
Because of the long anchor lengths, a 500t jack with a 600mm (24") stroke and an EZ Chair were supplied by DSI. The jack was modified in order to allow the DYWIDAG 12 strand Strand Anchors to fit through the center hole of the jack. To facilitate installation of the wedge plates and stressing head, an alignment plate that had the same hole pattern was used. The alignment plate was pulled to the end of the anchor and the wedge plates and stressing heads were guided onto the strands. In locations where a crane was not accessible to lift the DYWIDAG Anchors for installation, DSI provided a vertical uncoiler for easier installation of the anchors.