Newsletter: Proving Once Again That Time Is Money

Ductile Iron Pile Deep Foundation Solution Provides More Than 2 Weeks of Schedule Savings


Renovations at an existing high-bay, single-story building at 291 Mystic Avenue in Medford, MA required pile support for a new concrete slab. Traditional drilled micropiles with two rounds of post-grouting were designed to develop capacities of 20 tons. The specified system had to extend 40 feet deep and terminate in stiff to soft Boston Blue clay.

Helical was awarded the project based on competitive pricing for the specified micropiles. With an installation schedule approaching 4 weeks for the specified post-grouted micropiles, our team explored value engineering opportunities to save time and money. We contracted to perform a deeper boring to determine the depth to a competent bearing layer and identified very dense glacial till at depths around 75 to 80 feet.

A Ductile Iron Pile (DIP) alternative was developed consisting of Series 118/7.5 piles (118 mm outer diameter with 7.5 mm wall thickness) driven through the fill, organics and clay to terminate in glacial till or on rock after achieving set. The DIP solution was selected based on cost savings and more importantly a construction schedule that was less than half of the time despite the piles extending twice the micropile length. The installations were performed within the 20-ft high area by cutting piles and using couplers and also trenching for grade beams prior to pile installation. The result was a total of forty-two (42) 20 ton piles to match the micropile design installed to depths of 85 feet in only 7 working days.

The solution provided more than 2 full weeks of schedule savings.