Underpinning

Pit underpinning is a conventional underpinning method that stabilizes structures prior to neighboring excavation, using concrete and mortar. A partial width pit (panel) is excavated and shored by hand below the structure and extends to the underpinning design depth. The pit is afterward filled with concrete, leaving several inches of space beneath the bottom of the structure. Mortar is then packed into the space to give the load transfer. After the concrete and mortar attain sufficient strength, added adjacent panels can be constructed as necessary. The complete, cured underpin allows adjacent excavation to take place.