North Carolina Tub Crossing Repairs
The Job
This tub crossing repairs project is located in Charlotte, North Carolina. Fifty two OldCastle StarTrack panels at four different grade crossings settled to the point of requiring slow orders at the crossings. In order to restore the track to normal speeds, the settlement had to be corrected.
The Challenge
Due to scheduling constraints with rail traffic, with very short windows on weekend nights, the owner elected to have the repairs completed during a single weekend shutdown period. While this allowed for longer work periods, it also meant that four crossings needed to be repaired in fewer than 24 hours.
The Solution
CJGeo mobilized two polyurethane grouting crews to the system, and grouted two crossings each during two shifts. All 52 of the panels were stabilized and lifted back to grade using CJGrout 48NHL, which allows for immediate resumption of rail traffic, from light rail to heavy haul.
Polyurethane grouting is also sometimes called structural polymer grouting. Regardless of name, the process works very well where fast return to service is important. In the case of tub crossing repairs, grout must set very quickly in order for rail traffic to resume. CJGrout 48NHL achieves 95% of its ultimate strength in fewer than 15 minutes.
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Facing a similar challenge to this tub crossing repairs project by CJGeo? 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.
Rail Bridge Pier Stabilization
The Job
This rail bridge pier stabilization project is located adjacent to the Congaree National Park. This project was a capital repair to a bridge pier for a Class I railroad. The rail line serves the Port of Charleston, SC.
The Challenge
The Congaree River south east of Columbia, South Carolina frequently sees high flow events, inundating the surrounding low country. At the transition from timber trestle to a bridge, the first bridge pier was originally constructed of stone. The pier bears on a timber mat with timber pile supports. Over time, the river channel migrated and began to expose the timber substructure and scour below the pier.
The nearest road was more than four miles away through impassible swamp. So, all work had to be performed from the river. All material had to be pumped across the bridge, a distance of approximately 600 feet. Due to the compressive nature of the underlying materials, any backfill material needed to be as light as possible. But, due to the high likelihood of flooding, couldn’t contribute significant potential uplift.
The Solution
To address the scour, minimize additional load to the underlying soils, and ensure long term stability of the structure, a third party consultant designed a two tier sheet pile jacket for the structure. They specified the backfill material as 65lb/cuft cellular concrete for the lower segment. And, approximately 45lb/cuft cellular concrete for the upper segment.
CJGeo designed mixes which would meet these requirements:
- be pumpable 600LF,
- tolerate the high vibration environment from the more than 12 trains per day, and
- facilitate a short installation timeframe.
After the general contractor installed the first level of sheet piling and dewatered the area, CJGeo placed approximately 150CY of 65lb/cuft CJFill-Under Water material. Next came installation of the second, smaller diameter sheeting ring. CJGeo then filled the annular space between it and the necked down pier with 45lb/cuft CJFill-Standard material.
CJGeo generated and placed all of the CJFill low density controlled low strength material over a period of four days onsite.
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MSE Wall Lightweight Backfill
The Job
This MSE wall lightweight backfill project is located near Richmond, Virginia. The geotechnical investigation for a double bridge replacement in Amelia County, Virginia found a layer of compressible soils below four proposed abutments.
Anticipated settlement exceeded allowable settlement, so the abutments were designed to be backfilled with expanded shale lightweight aggregate.
The two parallel bridges have an AAWDT of 14,000. They carry a rural divided highway (US-360) over Norfolk Southern Railway & Business 360 in Amelia Courthouse, Virginia.
The Challenge
Lightweight fill placement had to be unaffected by frequent rail traffic, have a limited footprint, and be economical. The anticipated settlement at design was 2.5 inches. A challenge arose during construction mobilization due to Covid-related issues. There was nowhere to stockpile the lightweight aggregate onsite. But the trucking market was so unreliable, that the material needed to be staged onsite. This was to ensure continuous MSE wall construction.
The Solution
CJGeo provided a value engineering proposal to utilize 30lb/cuft CJFill-Ultra Lightweight cellular concrete in place of the expanded shale lightweight aggregate. This significantly reduced the unit weight of the lightweight fill. Given the 70lb/cuft density used in the design, further reducing the anticipated settlement.
CJGeo mobilized a 200CY/hour low density controlled low strength material (LD-CLSM) plant to the site and placed lifts ranging in size from 35 to 300CY. Wall erection crews were able to walk on the in-place cellular concrete without leaving footprints as quickly as 4 hours after each placement.
The total project volume was approximately 7200CY.
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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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Tub Crossing Repair
The Job
This tub crossing repair was done for a short line railroad in New Jersey. The sandy soils of South Jersey are great for growing produce and mining pure silica sand. While most of the produce is shipped by truck, a lot of the silica is shipped by rail. The rails inevitably cross the roads, and many of the crossings are at grade.
The Challenge
A short-line railroad was experiencing significant settlement and pumping of multiple precast modular crossings in the Vineland & Millville areas. Each crossing saw significant truck traffic, primarily from aggregate mining, and also significant heavy haul rail traffic from transporting sand.
Voids below the panels were holding water due to poor drainage. Each time a truck or train passed over the panels, they deflected downwards. This deflection pumps base material out from under the crossing, causing settlement.
The Solution
Working with a rail maintenance contractor, CJGeo performed polyurethane grouting on a total of four precast tub crossings in the area, using CJGrout 40NHL. Each crossing repair took a single day. Polyurethane grouting allowed for the immediate resumption of automobile traffic, and rail traffic. Th CJGeo crew installed supplemental bolting to address the deterioration of the panels resulting from the extensive movement of the panels.
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Facing a similar challenge to this tub crossing repair project by CJGeo? 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.
Industrial Short Line Tub Crossing Repair
The Job
This short line tub crossing repair project is located in Baltimore, Maryland. Sparrows Point, in Baltimore, Maryland is a brownfield site. It’s transforming from being steel manufacturing to industrial and logistics use. From it says as a heavy manufacturing facility, there is an extensive freight rail network throughout the site, with many grade crossings subject to significant heavy truck traffic & heavy haul rail traffic.
The Challenge
A precast tub-style grade crossing on a road feeding a metals recycling plant developed a 2.5″ belly. The local FRA inspector instructed the railroad to correct the settlement.
The Solution
CJGeo performed structural polyurethane grout injection to fill voids below the panels. And then lift them back into their correct alignment. The work took just a few hours, without disruption to the rail or auto traffic.
CJGrout 40NHL is a four pound per cubic foot geotechnical polyurethane grout. It’s specifically designed for high dynamic load environments like rail, port, and airfield traffic. CJGeo’s crews use 40NHL for modular grade crossing repairs to ensure the longest life repair possible.
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Facing a similar challenge to this short line tub crossing 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.
NC Tub Crossing Repair
THE JOB
This NC tub crossing repair project is located in Charlotte, North Carolina. The 8′ long panels of tub-style grade crossing settled. As a result, MOW placed a speed restriction on the crossing. This affected passenger schedules. The settlement affected three panels. The belly in the slabs was approximately 2 inches. The crossing deflected slightly with heavy truck traffic. The crossing deflected significantly with rail traffic.
THE CHALLENGE
The repair had to be completed in just a few hours, to avoid disruption to rail traffic. The repair had to allow for immediate resumption of rail traffic, and tolerate tamping of the adjacent truck during the repair. Additionally, the tub crossing repair had to be done in a manner that did not disturb the adjacent asphalt pavement.
THE SOLUTION
High-density geotechnical polyurethane grouting to stabilize and lift the affected modular grade crossing panels. Geotechnical polyurethane grouting is far superior to mudjacking, in that the process is faster, and can more easily ensure a complete filling of voids under the crossing panels. Lifting precision of fewer than 0.1 inches is standard.
A CJGeo modular grade crossing repair crew filled the voids and corrected settlement in a few hours. During the tub crossing repair, the rail system used a tamper on the approaches. This helps ensure the longevity of the grouting repair. The structural polymer grouting process used here is sometimes referred to as slab jacking.
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Facing a similar challenge to this NC tub crossing 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.
Industrial Driveway Crossing Repair
The Job
This industrial driveway crossing repair project is located in Frederick, Maryland. MARC’s Brunswick Line’s Frederick extension passes through multiple industrial sites & driveways. This particular crossing served as the driveway of a ready mix concrete operation, so saw extensive high dynamic loading in a wet environment.
The Challenge
The repair had to be performed without disrupting either rail or industrial traffic. There was a four-hour window between the last morning train and the first evening train for performing the repair to the eight modular tub crossing panels. The settlement was up to two inches, with extensive spalling.
The Solution
CJGeo’s crew installed supplemental bolts due to replace the OEM center panel anchors, and then grouted the crossing in the mid-day window, without disruption to any stakeholder. The structural polymer grouting work took less than a day onsite. The work was done between the morning and evening commuter trains, but multiple freight trains used the crossing during the repair.
CJGrout 48NHL was the grout of choice. CJGrout 48NHL is formulated specifically for high, dynamic loading environments, such as rail crossings, and airfields. It provides superior bearing capacity, excellent resiliency to dynamic loads, and is great for correcting differential settlement between panels. Because it is relatively low mobility, CJGrout 48NHL is unlikely to affect adjacent pavement.
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Facing a similar challenge to this industrial driveway crossing 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.
Light Rail Tub Crossing Repair
This light rail tub crossing repair project is located in Charlotte, North Carolina. It is part of Charlotte’s CATS system.
THE JOB
A suburban grade double-crossing was rebuilt to address poor drainage infrastructure in the area. This included installing two different culverts adjacent to the crossing panels, and then resetting all of the panels which had to be removed for the culvert installation. During routine track inspections, the panels showed signs of deflection up to one inch with rail traffic. The system’s track division was concerned that pumping of the crossing panels would lead to destabilization of the base, and settlement. At the lower elevation end of the crossing, there was extensive evidence of sub-base material being pumped out from under the crossing within two weeks of the crossing reconstruction. 368 track feet were affected.
THE CHALLENGE
Work had to be completed during non-revenue hours, between 0200 & 0430 over two nights. There was also a high probability of the voids below the panels being waterlogged.
THE SOLUTION
High-density polyurethane grouting to stabilize the grade crossing panels. Specially-formulated hydro-insensitive void filling (high-mobility) grout was proposed in order to ensure complete filling of voids below the panels, whether waterlogged or dry.
CJGeo successfully stabilized the crossing during the two-night work period.
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Facing a similar challenge to this light rail tub crossing 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.
Railroad Sinkhole Stabilization
The Job
This railroad sinkhole stabilization project is located in Martinsburg, West Virginia. During the installation of a 42″ jack & bore casing below a three-track Class 1 railroad, ballast started showing in the spoils. Soon afterward a sinkhole appeared between tracks 2 & 3, 15 feet above the casing. The jack & bore installation was stopped, and the contractor reached out CJGeo requesting an emergency mobilization.
The Challenge
CJGeo had to mobilize with very little notice, and work had to be performed adjacent to an operational track.
The Solution
CJGeo mobilized two polyurethane compaction grouting crews, who were on the road in less than an hour. Within four hours of the sinkhole formation, CJGeo was onsite with more than 250CY of material placement capacity.
CJGeo successfully grouted the sinkhole, using CJGrout 20SDB. Rail traffic continued on adjacent tracks, and the face of the bore was restored, allowing the jack & bore operation to safely restart. CJGeo performed this repair using a polyurethane grout with an elastic modulus similar to the existing soil in order to prevent creating a hard spot in the rail. CJGrout 20SDB was the best fit grout for railroad sinkhole stabilization project because:
- it cures to 95% strength within 15 minutes
- doesn’t impede auger boring
- is highly mobile, so will pass through ballast easily
- doesn’t have lifting capacity, so wouldn’t move the adjacent tracks
- is formulated for bulk placements without charring
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Facing a similar challenge to this railroad sinkhole 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.
