Building on Stability
Geo Grout Ground Modification Specialists, Inc. creates level footing for customers
Despite the appeal of living and working in the beautiful City by the Bay, many homeowners and building owners struggle with San Francisco soil quality and the challenges it creates for residential and commercial buildings. The snag? The city is built on loose sand and silt. Couple that with a location prone to earthquakes, and the problems multiply.
That’s why Geo Grout Ground Modification Specialists, Inc. (Geo Grout GMS) was founded. The geotechnical contractor specializes in a wide range of grouting techniques that solve soil and structural problems, says company CEO Steve Adams. Services include ground modification, shoring, grouting, grout consultancy and planning. Geo Grout GMS works with a range of clients, including commercial, industrial, local and state government agencies, residential, manufacturing and mining, he says.
“Liquefaction is a big problem here,” Adams says. According to the U.S. Geological Survey, that means that loose sand and silt, when saturated with water, can behave like a liquid when shaken by an earthquake. Earthquakes cause water pressures to increase in the sediment. The sand grains lose contact with each other, leading to the loss of strength. The soil can then lose its ability to support structures, flow down even gentle slopes and erupt to the ground surface to form sand boils. Many of these phenomena are accompanied by settlement of the ground surface—usually in uneven patterns that damage buildings, roads and pipelines.
“We have been called in to help on freeway projects, pipe installations and construction projects, as well as coming in to provide stabilization for existing projects. One we did after the big earthquake of 1989 was to help the foundation of the de Young Museum in San Francisco,” Adams says.
“I started the first incarnation of the company in 1990 after that devastating earthquake damaged so many large homes and commercial projects,” he says. “The main thing we do is improving the soil to allow construction on building sites. We can take non-buildable sites and make them suitable for construction. The second thing is stabilizing buildings that have settled. We can come in and inject the appropriate filler to level buildings and fix highways, airports, hospitals and many other kinds of structures.”
Plugging the Holes
Grouting procedures can be used in many applications. Adams says that if a construction project needs to be done in sand and requires excavation or if there is a structure that needs to be protected, his team can inject into the sand a permeation that allows the site to be excavated vertically. Geo Grout GMS injects the sand with various types of grout, which stabilizes the sand especially in regard to earthquakes.
Additionally, Adams says projects that are built in sand with neighboring buildings may require vertical cuts that can be stabilized with jet grouting. Jet grouting can also be used to stabilize footings and structures for large buildings that are settling.
For pipes under roads, Geo Grout GMS techs can help stabilize pipes that are settling or not lining up properly, says Tim Avery, Geo Grout GMS General Manager. “For pipe abandonment and displacement, grouting can be a solution. If they’re getting water intrusion, we can come in and grout the areas where the pipe goes through the sheet pile and stop the water from leaking in,” he says.
Avery explains that digging below ground for construction projects can be done in multiple ways. For a cofferdam, which is like a pit that retains water and soil, a contractor may put in sheet piles—usually a type of prefabricated wall to create a safe pit—to build a working area. The sheet pile may be round or square, but if water is coming in through the sheets, his team can do jet grouting or other kinds of grouting solutions to shut the water out to allow projects to be completed.
Essentially, the right kind of grouting can improve all soil conditions to allow contractors to do what they need to do, Adams says.
On a recent freeway project, Avery says his team helped by injecting a microfine cement grout around a 6-foot diameter shaft. A 4-foot ring of soil was grouted around the shaft to stabilize the soil to allow workers to complete their tasks. The grout was injected 50 feet into the soil to stabilize different zones throughout the area so that it wouldn’t collapse into the shaft.
“That allowed them to drill their holes with no cave-ins, and it saves them time and money by providing a support while they drill,” Avery says. “It can also be used to stabilize construction in sand for something like a bigger garage for a house or simply getting footings back up to where they should be and re-level homes, as well as freeways and roads.”
Rebuilding
Geo Grout GMS is in its second incarnation, Adams says. He sold the company in 1996 to some of his staff when he retired. That incarnation subsequently closed. Adams started a construction company in 1999 and realized that grouting was in his blood. Three years ago, Adams started Geo Grout Ground Modification Specialists with the desire to bring back quality, specialty grouting to San Francisco and California, he tells us.
Today, the firm runs a crew of 10 to 20 employees, depending on projects. Geo Grout GMS has three storage yards in the Bay Area in addition to its San Francisco headquarters. GeoGrout GMS recently hired Tim Avery, PE, as General Manager. Avery has been in the industry for over 30 years.
Geo Grout GMS is pursuing a Local Business Enterprise (LBE) certification from the city of San Francisco. According to the city, the LBE program promotes the participation of certified local businesses in city contracts by offering benefits that make their bids, proposals and qualifications more competitive than those submitted by non-local businesses.
“We are really excited about the LBE status,” Adams says. “It will give us a step up and allow us to grow and do larger projects. It is hard to compete with the big firms without that LBE status. The city requires their contractors hire some LBEs on jobs, and that will help launch us into a bigger realm.”
While Adams anticipates getting that proverbial foot in the door, he says the most important facet in growing the business centers around providing high-quality service to customers at a reasonable price.
“Anyone can be in business and do something. The differentiating factor is providing quality work,” he says. “Companies go in with a low bid and cut corners. With pressure grouting, if you cut corners, you can inject very quickly, but it cuts and slices in and you don’t want to do that. You need to pump slowly so the grout doesn’t slice or fracture.”
He adds, “We’re often hired to fix projects that were performed incorrectly the first time.”
“Quality is the key in the business. We’re going to provide a quality product, and we won’t go in and do it too fast. When we leave a work site, they’ll have something they can depend on,” Adams says.