Stone Arch Lightweight Backfill
The Job
This stone arch lightweight backfill project is located in Somerset, New Jersey. The stone arch bridge, constructed in the 1800s, was experiencing significant scour at the bases of the arch. This caused differential settlement of the structure, and deterioration of the wing walls.
The bridge is adjacent to a historic mill structure. Due to historic preservation requirements, the structure had to be maintained in kind, as opposed to replaced.
The bridge was originally bearing on shallow stone foundations.
The Challenge
As part of rehabilitating the structure, structural engineers designed two new mass footings in the stream bed to underpin the edges of the stone arch. Then, to strengthen the arch designed a 12″ thick reinforced concrete arch overlay on top of the stone arch for the full length/width of the bridge.
In order to compensate for this additional weight, designers determined that a lightweight fill material was needed to reduce the chances of inducing settlement.
Designers also evaluated remedial deep foundations but determined that lightweight fill was the fastest and most economical solution.
The Solution
After the structure had been rehabilitated, CJGeo installed 325CY of 30lb/cuft CJFill-Ultra Lightweight to complete the stone arch lightweight backfill installation. Placed in lifts up to 4 feet thick, the work was took just three days.
By using 30lb/cuft closed cell cellular grout, the dead load on the underlying soil decreased by up to 935lbs/sqft relative to compacted soil backfill.
Cellular concrete is self-consolidating and pumpable hundreds of feet. Therefore, single side access was not a problem, and no compaction equipment was necessary.
A crew of two workers completed the pour using continuous wet batch generation. CJGeo chose wet batch generation due to the relatively small daily volume of material placement.
Speak With An Expert
Facing a similar challenge to this stone arch lightweight backfill 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.
Coal Pier Sinkhole Grouting
The Job
This pier sinkhole grouting project by CJGeo is located at the mouth of the Elizabeth River, off the Chesapeake Bay. With an annual throughput capacity of 48 million tons, Norfolk Southern’s Pier 6 at Lamberts Point in Norfolk, Virginia is one of the largest coal trans-loading facilities in the world. As an around-the-clock facility built around precision logistics, there’s little tolerance for disruption or downtime.
The Challenge
When two sinkholes opened up at the end of Pier 6 adjacent to the bulkhead, railroad personnel reached out to an onsite maintenance contractor. Steel plates were installed to provide temporary protection while a long-term solution could be implemented.
The Solution
CJGeo performed DCP testing at the site in order to quantify the depth of voids below the pavement adjacent to the sinkholes. The DCP testing showed that in addition to large voids visible from the sinkholes immediately below the pavement, there were large pockets of voids down to 15’ below the surface.
CJGeo crews then used CJGrout 35NHV61, a hydro insensitive, NSF-certified geotechnical polyurethane to fill all voids and restore stability to the area. The grouting work took five hours onsite to install 3400 pounds of material, with zero disruption to operations.
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Facing a similar challenge to this pier sinkhole grouting 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.
PA Turnpike Undersealing
The Job
This PA Turnpike undersealing project is located on the Northeast Extension of the Pennsylvania Turnpike. The Northeast Extension runs from Philadelphia to Scranton. As part of a 24 lane mile mill & pave rehabilitation on the Pennsylvania Turnpike, slab stabilization was required. The Turnpike’s specification for stabilization is either liquid asphalt or polyurethane.
In this work area, the turnpike has two northbound and two southbound lanes. A cast in place barrier wall separates the lanes. The pavement is an approximately nine inch thick rigid concrete with up to eight inches of asphalt overlay. Joint spacing ranges from twenty feet to eighty feet.
The Challenge
In order to keep MOT in place continuously, work had to be done 24 hours per day. Multiple mobilizations were used to work around bridge repairs at three different overpasses in the undersealing work area.
The Solution
CJGeo proposed undersealing with CJGrout 40NHL, a 4.0 lb/cuft free rise polyurethane grout formulated specifically for undersealing thick pavements in transportation environments. 40NHL is hydro insensitive, so performs well in wet environments, as confirmed with NYSDOT GTP-9 testing.
Using a double gang drill and single grout truck, CJGeo crews undersealed up to 1.8 lane miles per shift. Drilling operations happened overnight. Grouting during the day is safest, and allows for easy visualization of the entire zone of influence. By working continuously, the general contractor was able to keep MOT in place continuously, avoiding the cost of setting and pulling MOT each day.
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Facing a similar challenge to this PA Turnpike undersealing 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.
Bridge Approach Polymer Grouting
The Job
This bridge approach polymer grouting project is located just outside of Washington, DC. The George Washington Memorial Parkway connects Washington, DC with Fairfax and Alexandria Counties in Virginia. Originally designed as a scenic route, the road has transformed into a heavily used commuter route in and out of Washington. The road runs along the Potomac River, with bridges crossing deep ravines, including Windy Run.
The Challenge
Our biggest challenge with this project was making sure this heavily populated commuter route was completed in a timely fashion.
The Solution
CJGeo proposed polyurethane compaction grouting using CJGrout 30NHL. CJGrout 30NHL’s design is for improving the bearing capacity of loose soils similarly to cementitious compaction grouting. Grouting is done on 4’ centers, at 5’, 10’ & 15’ below grade. Top-down grouting ensured maximum densification of underlying soils. This grouting program was generally prescriptive, but with ground movement of 0.5 inches cutoff criteria.
CJGeo installed approximately 25,000 pounds of CJGrout 30NHL to increase the bearing capacity of the embankment soils. Due to polyurethane grout’s nearly immediate cure, CJGeo helped ensure that ground improvement stayed out of the critical path of this accelerated project. Pre & post grouting DCP testing showed improvement in soil density.
Speak With An Expert
Facing a similar challenge to this bridge approach polymer grouting 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.
