Retaining Wall Built with Techno Metal Posts

When a customer contacted TMP's Central Iowa dealer, Corey DePenning with a request for a retaining wall, he was reminded of an original stained wood and steel retaining wall project by another TMP dealer near Toronto, Canada. He proposed this idea to the customer, and without hesitation, the project was launched. These types of retaining walls are more often seen in commercial projects, but helical piles can be used on almost any scale, making a residential helical pile retaining wall an effective and durable solution. The wall, measuring 100 feet long and anywhere from 6 to 10 feet high (depending on the section), proved to be challenging. This was mainly due to the time required for the job and the difficult area to work on, but the final results made it all worthwhile.

Techno Metal Post piles were required to have a minimum embedment depth of ten feet. The project was designed by a certified engineer from the state of Iowa, who recommended using P5 piles (5.563″ x 0.258″ O.D shaft size) every 6' on-center for the wall, custom caps were designed with W8x18 soldier pile beams above, and  P3 (3.5″ x 0.216″ O.D shaft size) tie-back anchors, installed at a 15-degree angle.

Location: Des Moines, Iowa

Obstacles: Existing retaining wall and tree roots

Soil type: Black earth and clay mixed with shale at about 14' depth.

Advantage: Cheaper than driven H piles and much less time-consuming. The entire wall was completed in one week.

Materials: P5 piles (563″ x 0.258” O.D shaft) for the wall and P3 dual helix (3.5″ x 0.216″ O.D shaft) as tie back anchors.

Equipment: EM1 machine