Foundation Repair Case Studies: Commercial Foundation Piering Project

Wednesday, June 20th, 2018

Challenge

A leak in the sprinkler system caused this office building to settle.

Excessive water can have a very detrimental effect on a structure’s foundation.

The owners of this office building contacted Thrasher when they were remodeling two suites along the south wall. When the carpet was pulled back, large cracks and a sloping concrete floor were exposed. The owners initially thought that mudjacking the slab floor was all that would be needed to fix the problem. Our Thrasher field consultant conducted an inspection and evaluation and determined that the building's front had settled approximately an inch and a half. Additional examination revealed that the building's sprinkler system was leaking about 200 to 300 gallons of water per day in this area.

When it comes to settlement, the cause is always the soil. Our clay-based earth in the area undergoes large expansion and large contraction depending on the elements. When clay soil comes in contact with moisture is softens and swells. The can cause foundation footings to drop into the softened ground. When clay soil gets dry, like in a drought, it shrinks. When this soil shrinks, voids can get created under the footing and cause the structure to sink into that void. The final element that can affect the ground is the compaction process during the build. Before a structure is built, developers move soil around the building site to grade and level for footings to be poured. This movement often disrupts dense virgin soil. Once disrupted, that soil will never be as compact as it once was. This will cause small cracks and voids in the replaced soil. Then we put a hefty structure in that soil. This can cause the structure to settle into the small cracks and gaps created during the building process. 

In this particular circumstance, mother nature was not the main culprit. As new products are developed to make owning a building or home more desirable, those products can often fail. Such as sprinkler systems. A small leak over time can soften and swell the soil right next to the foundation. Additionally, elements out of our control, such as rain and drought and foundation problems, can happen quickly and without warning. 

Some warning signs to look for in your home or building include; Cracks in drywall, sticking doors and windows, cracks around windows, cracks in the brick mortar or block mortar, cracks in the floor, uneven floors.

Too much water around your foundation can cause major structural damage. Thrasher provides interior and exterior waterproofing and drainage system solutions for homes and businesses.

These signs and symptoms are evidence that one part of the foundation is moving at a different rate than another. 

To fix settlement permanently, you must bypass all the problem soils. These soils often are far below the footing of the foundation. Our team of highly trained individuals utilize a hydraulic press to push a steel tube into the ground straight down from the structure's footing. These piering tubes reach a depth of soil competent enough to hold several times the weight of the structure. Also, the piers are load-tested as they are pushed into the ground to ensure they are deep enough and straight and will hold the structure for many years to come. Every building has a different weight and size of footing. These factors cannot be left to guesswork. We have multiple structural and geotechnical engineers that can help design a solution for any structure on staff. Often, the piers themselves can hold much more weight than the footing of the structure. This is where most get it wrong. It is essential to determine the load of the pier and the spacing in which the footing can handle. Thrasher's engineering team designed a repair plan utilizing 16 Atlas resistance piers to lift the building's south wall back into place. Now this office building can make the necessary cosmetic repairs inside and outside without worry of them reappearing or getting any worse. 

Most Pier projects can be done within one week and cause little disruption to everyday life. Thrasher completed the project in 4 days without interrupting the tenants' daily operations in the building, allowing the remodeling project to resume and be completed on schedule.