Corporate HQ Stabilization
The Job
Starting immediately after construction was completed, the slab on the grade floor within the cafeteria, loading dock, and kitchen at a corporate headquarters building in Pittsburgh, Pennsylvania settled. Over the course of 12 years, the owner had four different grouting companies attempt to address the problem. Lime slurry injection below the slab was disruptive, and settlement always resumed shortly thereafter.
Compaction grouting was performed in one area but was so disruptive that despite the fact that it was the only method where settlement didn’t resume, the owner kicked the contractor off the site after nearly four months of not having access to their executive dining room.
The Challenge
Settlement progressed over time to be as much as four inches, affecting nearly 20,000 square feet of floor. A general contractor retained by the owner reached out to CJGeo about performing low-impact grouting to address the settlement.
Because settlement affected the entire kitchen, food prep, serving and majority of the dining areas, repairs had to be facilitated continued use of the facility. Additionally, due to the 24-hour staffing of the facility, the noise had to be limited, and there was zero tolerance for dust.
Video inspection of the extensive gravity sanitary and floor drains below the floor revealed six defects, including a 2″ offset in a sanitary drain line for a 6 stall restroom.
The Solution
CJGeo performed 17 DCP tests to determine the depth of uncontrolled fill, which was the presumed cause of settlement. DCP testing showed pockets of WOH fill down to 35′ below the finish floor, and voids ranging from 2″ to 18″ immediately below the floor.
Over the course of 7 nights onsite, CJGeo crews installed 12,000 pounds of CJGrout 20SDB into voids immediately below the floor, and 53,000 pounds of CJGrout 35NHV61 for polyurethane compaction grouting. Compaction grouting was performed up to 35′ deep, but to an average depth of 15′ over the entire area.
All work was completed off-hours. As soon as the kitchen shut down for the evening, CJGeo crews swung into action, grouting through the night until wrapping up in time for the food prep crews to get ready for breakfast at 0500.
To facilitate grouting under four walk-in freezers and refrigerators, over the course of a 24-hour shift, all cold contents were moved to reefer trailers, CJGeo grouted to 30′ under the freezers and refrigerators, which were then immediately turned back on, and then refilled.
Through careful coordination with multiple operational divisions for the owner, general contractor, flooring restoration contractors, plumbers, and remediation contractors, CJGeo successfully completed the project under budget and on time.
Speak With An Expert
Facing a similar challenge to this project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Sewer Collapse Sinkhole Repair
The Job
This sewer collapse sinkhole repair project is located in central Virginia. When the operators of a tire and auto shop noticed a sinkhole developing next to their building. They weren’t sure what to do. After an employee crawled into the hole and discovered that he could stand up underneath their building, the owner reached out to the city. City crews determined that a 20″ VCP combined sewer & storm pipe had collapsed under the structure, roughly 25′ below grade.
The Challenge
An on-call contractor for the city installed a new manhole and rerouted the pipe around the building. However, addressing the sinkhole was out of their businesses’ scope. The project manager reached out to CJGeo, who visited the site and recommended DCP testing to better quantify the extent of the problem.
The Solution
DCP testing showed that outside of the large hole on the surface, there was little deep disturbance. Working with the city’s consulting engineer, CJGeo developed a grouting plan to install two different CJGrouts. 20SDB in the bulk voids near the surface. And 35NHV61 for soil grouting to address voids within the underlying ground near the failed sewer line.
While onsite for just 6 hours, a CJGeo crew completed the work with zero disruption to the businesses’ operations.
Speak With An Expert
Facing a similar challenge to this sewer collapse sinkhole repair project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
School Floor Leveling
The Job
This school floor leveling project is located in Princeton, West Virginia. The Princeton Middle School is a slab-on-grade masonry structure and serves approximately 550 students in grades 6 through 8.
The Challenge
The corridor floor in the arts wing settled up to 3.5 inches. A geotechnical investigation found voids up to 2.5 inches below the settled slab. Due to budgetary constraints, the repair needed to address the settlement & instability without requiring flooring replacement.
A hand auger confirmed that the fill material below the slab had consolidated to the point of providing sufficient capacity. So, there was no need for polyurethane compaction grouting, which would have been useful if the soils were still loose.
The Solution
CJGeo mobilized a two-person polyurethane grouting crew to the site. Over a few hours, they filled all the voids utilizing CJGrout geotechnical polyurethanes and corrected the settlement. After the floor was lifted back into position and the voids all filled, the custodian reinstalled the cove base at the correct height. CJGeo patched the injection holes with off-white stained grout to match the VCT flooring.
CJGeo used CJGrout 28FDL for this repair. 28FDL is a fast, dry environment lifting foam that works great for lifting bellies out of lightly loaded slabs. There were no water leaks below the slab, there was a significant belly, and the loads were less than one tenth of the grout’s capacity, so it was a great fit. To make sure there weren’t any remaining voids, the crew installed CJGrout 20SDB, which is higher mobility than 28FDL.
Speak With An Expert
Facing a similar challenge to this school floor leveling project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Tunnel Abandonment – Boston
THE JOB
A plumbing contractor hand tunneled 140LF of 4’x5′ tunnel under two apartment buildings near Boston, Massachusetts. In preparation for a renovation project, a structural inspection was performed. The structural inspection revealed the slab floors which were tunneled under were not designed as structural slabs. The structural engineer directed the property owner to immediately fill the tunnels to restore structural integrity.
THE CHALLENGE
The tunnel abandonment work had to be completed during the winter, and while one of the two affected buildings was occupied. The non-occupied building was also in the process of asbestos abatement and a full gut renovation.
Due to the plumbing running through the tunnels, an excavatable grout was required. Also, the grout had to be low exotherm in order to not affect the new PVC plumbing.
THE SOLUTION
CJGeo proposed polyurethane grouting for the tunnel abandonment. Polyurethane grouting can be performed in any weather, is low exotherm, and can be placed in very thick lifts. The specific grout chosen was a low exotherm bulk void filling polyurethane.
CJGeo mobilized a polyurethane grouting truck with more than 9000 pounds of polyurethane grout, due to the unknown exact volume of the tunnels. During an 8″ snowstorm, CJGeo abandoned both tunnels in a single day. The unoccupied building was grouted via holes drilled through the floor. The tunnel below the occupied building was free sprayed from inside the tunnel. All tunnels were kept under negative pressure ventilation in order to address installation odors.
CJGeo placed 4100 pounds of polyurethane grout into the two tunnels.
Speak With An Expert
Facing a similar challenge to this project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Office Floor Settlement Repair
The Job
This office floor settlement repair project is located near Norfolk, Virginia. The slab floor inside of a grain import/export facility office sank both differentially and globally. All exterior walls are on driven timber piles, but the floor floats independently of the foundations. Slab settlement up to 3 inches affected approximately half of the building footprint.
The Challenge
Over the roughly 15 years that the floor was settling, maintenance crews were constantly repairing various systems. These repairs were including tuckpointing CMU walls, moving/shimming HVAC ducting, and rerouting water lines.
The foundation repair work on this building couldn’t impact operations. Ship loading and unloading could not be disrupted for any reason. The settled building houses many operations critical to ensuring timely loading and unloading.
The Solution
CJGeo proposed polyurethane grouting for this slab foundation repair project. Polyurethane grouting is safe, fast, and economical for floor settlement repair. Structural polymer grouting is another name for polyurethane grouting. The material of choice was CJGrout 28FDL. 28FDL is optimal for lifting light duty commercial floors experiencing both global and differential settlement.
CJGeo mobilized two polyurethane grouting crews to the facility on a Saturday morning. The 4,000 square foot repair only took nine hours start to finish. There were zero disruption to operations. During lifting, previous cosmetic repairs were undone to facilitate lifting. This included removing extensive patch material from the CMU walls, loosening plumbing connections, and adjusting HVAC ductwork.
By mobilizing multiple crews with multiple equipment redundancies, CJGeo was able to ensure that the repair had zero disruptions to the facility and its operations.
Speak With An Expert
Facing a similar challenge to this office floor settlement repair project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Port Shed Floor Stabilization
THE JOB
This port shed floor stabilization project is located in Baltimore, Maryland. The 11″ thick slab floor of a storage shed at a port facility settled up to 6 inches. Exploratory coring & non-destructive imaging (GPR & microgravity) indicated there were extensive voids below the floor.
Previous work on the adjacent bulkhead uncovered extensive voids below the exterior footings (pile-supported) and multiple abandoned, but unfilled, pipes under the floor.
THE CHALLENGE
Due to relatively thin voids, which were all less than 6 inches, and void filling grout had to be highly mobile. However, this posed environmental challenges due should the grout make its way into an unfilled abandoned pipe and into the adjacent waterway. The owner did not want to lift the floor, so grouting had to be sufficiently low mobility to prevent runaways, but also fill all voids at an economical hole spacing.
THE SOLUTION
CJGeo proposed polyurethane grouting for this slab foundation repair project. The original design was for a 50/50 mix of polyurethane and cement grouting. CJGeo proposed a valued engineering proposal to perform all grouting with polyurethane. CJGrout 35NHV geotechnical polyurethane grout was proposed to balance mobility for completeness of fill and reaction time to avoid any runaway loss into the adjacent waterway.
CJGeo mobilized a two-reactor polyurethane grouting rig and installed approximately 6300lbs of polyurethane grout over a three-day period. Pneumatic rock drills were used to speed drilling.
Speak With An Expert
Facing a similar challenge to what CJGeo addressed on this port shed floor stabilization project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Commercial Floor Void Fill
THE JOB
This commercial floor void fill project is located in Manhattan. During a Local Law 11 inspection, the owner of a coop building’s first floor asked the GC to investigate a settled slab floor inside part of the building. The contractor began opening up a 2′ square hole in the floor. During this, all the debris was disappearing. After opening the hole it was apparent why. There was a 2′ to 3′ deep void around the entire perimeter of the building footprint.
THE CHALLENGE
Filling a 90CY void under the floor of an operating business can be a challenge anywhere. Complicate it with a 40′ x 10′ laydown area, Mid-Town Manhattan traffic, and cold winter temperatures, and you’ve got quite the challenge.
The cause of settlement was the consolidation of poorly placed fill, which was primarily construction debris. Lightweight void filling material is best to minimize future settlement of the underlying fill material.
THE SOLUTION
At the suggestion of an on-staff structural engineer, the general contractor’s project manager reached out to CJGeo about performing polyurethane grouting to fill the voids. CJGeo proposed using a low-exotherm, high mobility bulk void filling foam to fill the voids. 3′ deep voids are too deep to fill with most polyurethane grouts. A true low exotherm foam is needed for efficiently and safely filling any voids thicker than about 6″. High mobility foams are also critical when filling voids in order to ensure complete coverage.
CJGeo mobilized a two-reactor polyurethane grouting rig. The CJGeo crew installed approximately 4800lbs of CJGrout 20SDB geotechnical polyurethane grout over a two-day period. CJGeo pulled continuous negative pressure on the void through the floor. This was to allow for continuous operation of the facility during grouting. CJGeo’s work didn’t disturb operations at all. All of the voids were completely full of grout at the end of the project. The polyurethane grouting process used here for slab foundation repair is sometimes also called slab jacking or structural polymer grouting.
Speak With An Expert
Facing a similar challenge to this commercial floor void fill project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
Chemical Underpinning
The Job
This chemical underpinning project is located outside of Pittsburgh, Pennsylvania at a manufacturing facility. Water began to seep through the floor of the shop, break room, and bathrooms inside a manufacturing facility. The investigation determined that a water line had broken, and weekend soils below the floor, causing the settlement. Voids were also present below the floor.
The Challenge
The client’s primary concern was addressing the stability of the area without affecting normal usage.
The Solution
CJGeo proposed chemical grouting to stabilize the weakened soils, along with structural polyurethane grouting to fill voids. Previous repairs to address floor settlement had been completed, so a hydro-insensitive undersealing polyurethane grout was used to ensure stability without lifting the slab.
Due to saturated soils, CJGrout 35NHV was the best material for filling voids immediately below the floor. 35NHV is a normal speed, hydro-insensitive geotechnical polyurethane, specifically formulated for void filling applications. It provides high bearing capacity, and minimizes the chance of undesirable lifting during installation.
Speak With An Expert
Facing a challenge similar to this chemical underpinning project? Give us a shout or shoot us a text. Click the state marker for the location of the project for contact info for the appropriate rep.
