Situation

A major flood caused the Pawtuxet River to rise to levels not seen in the last 100 years, undermining two historic buildings. The primary concern was the risk to the public caused by potential further building collapse, and a secondary concern was to minimize disruption to businesses operating in the buildings.

Challenge

One building had partially collapsed and needed to be further demolished. The other building had a severe crack that was continuing to grow as the river washed away more supporting ground. Allowing the buildings to collapse would have blocked the river and created a flood in the surrounding community. Temporary reinforcements were needed, but the only physical access to the site was from the river itself, which put otherwise very experienced contractors in situations they had never experienced before.

Solution

Pieces of the collapsed building were moved out of the way, and a portion of the parking lot was sacrificed to construct a ramp into the river, allowing a 110k lb excavator to drive through the river and construct a wall of concrete blocks. The wall would divert the river away from one of the buildings to prevent undermining until high-pressure concrete could be pumped under the footings to again stabilize the building.

Results

Further damage to both historic buildings was prevented. Structural stability has been reestablished. Thielsch Engineering restored temporary water and fire mains to the buildings and inspected and recertified the electrical systems. This prevented the buildings from being condemned and allowed the owners to continue operating their businesses with minimal disruption. We then assisted the owner in obtaining a sponsor for federal financial grant money, and we are currently bringing about permanent repairs.