Composite Underpinning System in Harsh Winter Conditions-Video

Video Transcription

Video Summary

Alan Wodka describes the underpinning and excavation work for Somerville High School’s $256 million renovation. The steep site contained a four-story brick building dating to 1895, and the work required supporting the existing structure while demolishing and replacing the C wing.<br /><br />The original plan used hollow-bar micropiles to carry building loads, followed by soil nailing and excavation. Asbestos, an unexpected rubble foundation, and redesigns forced a change in sequence and delayed the start from summer to December 2018. Crews worked through severe winter conditions, limited access, snow, and difficult soil-hauling logistics. At the rubble-wall section, they installed soldier piles with permanent tiebacks and shotcrete lagging.<br /><br />Despite the challenges, soil nail and movement tests showed satisfactory performance, and measured soldier-pile movement remained minimal. The six- to seven-person crew completed the work on April 4, 2019—about ten days after the revised target date. Wodka emphasizes that out-of-sequence construction, more than cold weather, was the project’s main difficulty.

Keywords

Somerville High School

underpinning

excavation

micropiles

soldier piles

soil nailing