The geotechnical needs of DOTs and other agencies responsible for roads and bridges are vast. Issues include: Culvert repair Soil stabilization Void filling Concrete slab lifting Sinkhole remediation Slope control Slough control in tunneling
Protecting concrete usually means shielding it from the elements of nature or from harsh manmade chemicals. But it’s not just concrete that needs such protection. Corrugated metal pipe, steel surfaces, material hoppers, rail cars and masonry all can come in contact with corrosive or abrasive materials or harsh conditions.
Client: Port of Palm Beach, West Palm Beach, Florida
The Port of Palm Beach is the busy base of operations for many different types of businesses. These range from container shipping to cruise ship departures. One of its clients refurbishes luxury yachts. The port engineer found significant cracks in the seawall adjacent to this client’s main work area. The cracks created major voids behind the wall as the tidal activity washed away loose soil.
Port officials hired a local contractor to repair the seawall. The company could have done a rehabilitation using excavation and backfill and some type of sheet pile or a cementitious patching of the concrete. However, besides being disruptive to the port’s operations, particularly those of the client in that area, such a large-scale rehabilitation is an expensive proposition. In addition, depending on the repair method chosen, patching might be only a short-term solution.
The contractor recommended curtain grouting the seawall using Prime Flex 920, an expansive polyurethane foam, to fill the voids, stabilize the loose soil, and seal the cracks in the seawall. When reacted, the hydrophobic foam forms a rock-hard watertight mass.
The crew initially pumped Prime Flex 920 with probes in five locations. This filled the original void, the known cracks, plus fissures underwater that had not yet been discovered. A floating boom contained any reacted grout, which is inert, as it flowed through the cracks in the seawall. Seawall Doctors and port officials chose Prime Flex 920 because it is certified compliant with NSF/ANSI Standard 61 for contact with potable water. Though the waterway is not a source for drinking water, choosing an eco-friendly product to use was an easy decision.
After the initial grouting phase, port officials chose to have additional grout installed to fill other voids and ensure the sealing of cracks not yet discovered.
The crew completed the project successfully over three days without disrupting port operations or interfering with the client’s job of getting a luxury yacht back on the water.
The port authority official said this solution saved $100,000 from the other options that were explored.