NY Grade Crossing Repair
The Job
10 panels of StarTrack modular grade crossing tubs settled in an urban street crossing owned by a short line. As a result of the settlement multiple clips broke. This caused the panels to pump.
The Challenge
The crossing tubs settled, and when crossed by trucks, pumped water containing the sub-ballast up between the tubs and adjacent pavement. The adjacent track also settled significantly.
The Solution
CJGeo proposed grouting immediately below the panels, and also into the underlying disturbed subballast using CJGrout 48NHL geotechnical polyurethane grout.
The CJGrout 48NHL was injected through 5/8″ holes drilled through the panels. The settlement pattern of each panel determines the specific hole spacing. It takes about five minutes for the grout to cure to 95% of its ultimate strength. After grouting, it’s important to tamp the approaches. Because the rails are clipped, lifting the panels lifts the rails & ties in the approaches. If the approaches aren’t tamped, the crossing can teeter totter, which is bad. Tamping is done immediately after grouting, and preferably before any rail traffic resumption.
CJGeo performed the StarTrack modular grade crossing repair without impacting rail traffic. The facility was able to function normally throughout the repair, which took less than a day.
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New York Tub Crossing Lifting
The Job
Eight panels of StarTrack modular grade crossing tubs settled. As a result of the settlement multiple clips broke. This tub crossing lifting project was for a short line serving an industrial facility in Geneva, New York.
The Challenge
The crossing tubs settled, and when crossed by trucks, pumped water containing the subballast up between the tubs and adjacent pavement. The crossing was the only entrance into an industrial facility that took two trains per day. Because of limited onsite storage, rail service couldn’t be disrupted at all.
The Solution
CJGeo proposed grouting immediately below the panels, and also into the underlying disturbed subballast using CJGrout 48NHL geotechnical polyurethane grout. CJGeo performed the tub crossing lifting work without impacting rail traffic, and the facility was able to function normally throughout the repair, which took less than a day.
Polyurethane grouting with CJGrout is an excellent alternative to cement based grouting, because:
- CJGrout cures within a few minutes, so there are no limitations on rail traffic
- CJGrout is not brittle, so does not break down in dynamic environments like thin layers of cement-based grout tend to do
- CJGrout application is not weather dependent; in this case, it was snowing during installation
- CJGeo controls the entire CJGrout logistics process, so there’s no need to wait on ready mix trucks or coordinate deliveries of material that goes bad within a few hours of offsite mixing
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Illinois Spillway Grouting
The Job
A spillway serving as a dam for a lake owned & maintained by a property owner association outside of Carbondale, Illinois stopped having water flowing over the spillway, requiring spillway grouting. The property owners determined that the lake was draining through voids under the spillway slab. This made them concerned about destabilization of the spillway, which was the sole access for six homes.
The Challenge
The flow velocity was rather high, and immediately on the other side of the spillway was a 30′ cliff. The water was designed to spill over as a waterfall. Given the extraordinary difficulty of retrieving any material washed over the waterfall, the grout had to have an exceptionally fast set. It also needed to provide adequate bearing capacity for the roadway slabs.
The Solution
CJGeo proposed grouting below the spillway with CJGrout 40NHL. CJGrout 40NHL is usually used for differential settlement correction. CJGrout 40NHL performs well for differential settlement correction because it reacts very quickly. It’s used for medium duty lifting, such as highway pavement, so it would provide more than enough bearing capacity.
The owners were very excited that it would be significantly less expensive to grout the existing spillway than to have someone local install a portadam and replace the entire structure. CJGeo mobilized a single polyurethane grouting crew to the site. They stopped the leaks and kicked all the water flow over the spillway in a single day.
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I-64 Soundwall Backfill
The Job
VDOT’s I-64 widening project is a multi-phase widening of Interstate 64 between Richmond & Newport News. This soundwall backfill work occurred as part of Segment 2, near the Queen’s Creek bridge.
The Challenge
Approximately 150LF of a combination sound & retaining wall needed to retain more than 10′ of backfill. In order to keep the drilled foundation size consistent along the alignment, the backfill material needed to be significantly lighter than the soil backfill used in other segments, where there was minimal retained depth.
The material needed to be freely-draining and less than 40lb/cuft. To ensure proper drainage, the lightweight fill material couldn’t impact the function of the combination drain waterproofing system applied to the wall.
The Solution
CJGeo proposed backfilling the affected wall segments with 30lb/cuft CJFill-UL. Used extensively by VDOT for backfilling the retained zones of MSE walls, CJFill-UL provides significantly better bearing capacity than soils or aggregates, and once cured does not apply lateral loads to the structures it is placed against.
During installation, lateral pressure from the cellular concrete is simply the hydraulic head. Hydraulic head is calculated by multiplying the pour thickness, in this case 5′, by the wet cast density, here 30lb/cuft, so 150PSF. Because CJFill-Ultra Lightweight cellular concrete does not contain any aggregate, there is no internal friction to contribute towards lowering pressures.
CJGeo placed approximately 200CY of CJFill-UL for the soundwall backfill the wall in two pours, each approximately 5′ thick. The contractor was able to place the pavement base on top of the material the following day.
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Veranda St Bridge Infill
The Job
This bridge infill work was part of Maine DOT’s Veranda Street Bridge Replacement Project, in Portland, Maine. Using rapid bridge replacement, the project took a three span bridge and converted it to a single span bridge.
The Challenge
To manage settlement due to up to 80′ of underlying WOH material, lightweight fill was needed to infill two spans, and backfill the new abutments. The absolute lowest unit weight possible requirement led to a hybrid cellular concrete/EPS fill design. The bulk of the infill is EPS blocks. However, due to the irregular surfaces, piers, etc., and the need for a lightweight load distribution slab, cellular concrete was integral to the design.
The Solution
Over two mobilizations for the bridge infill, through snow and freezing temperatures, CJGeo placed 3200CY of 25lb/cuft CJFill-Ultra Lightweight cellular concrete for abutment backfilling and existing pier infills. Then, CJGeo placed 778CY of 30lb/cuft CJFill-Ultra Lighweight as a topping slab over the EPS fill masses.
To ensure high quality material and minimize weather-related risks, CJGeo used onsite batching to generate the material. A mobile batch plant custom built for generating cellular concrete mixes water and dry bulk cement onsite. The cement paste and foam blend continuously to generate a completely homogenous material. With a slump of around 11.5 inches, both densities of CJFill-Ultra Lightweight cellular concrete were able to flow around all of the existing structures and provide a void-free fill.
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New Jersey Grade Crossing Stabilization
The Job
This grade crossing stabilization project is located in Edison, New Jersey. A precast modular grade crossing (Oldcastle StarTrack) crossing developed significant pavement deterioration. NJDOT directed the railroad to stabilize and lift the panels and then patch the adjacent asphalt.
The Challenge
The grade crossing sees up to 8 trains per day (heavy industrial service), and crosses a four lane arterial highway. So, there wasn’t any allowable downtime. Because of this, traditional cementitious grout was not a viable option. Cementitious grouts generally need hours to reach strength, so can significantly disrupt train schedules, and require long lane closures for vehicles.
The Solution
CJGeo proposed grouting the panels using CJGrout 60NHL. 60NHL is a geotechnical polyurethane grout specifically formulated for heavy applications such as rail and aircraft loads. A CJGeo polyurethane grouting crew mobilized to the site and in fewer than 2 hours onsite restored the affected panels. Another name for this process is concrete raising.
This grade crossing stabilization project did not require ground improvement grouting. The cause of the settlement was the bedding fines washing out, so only shallow grouting was necessary.
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Facing a similar challenge to this grade crossing 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.
Garden State Parkway grouting
The Job
This Garden State Parkway grouting project is located near Middletown, New Jersey. As part of ongoing large diameter culvert rehabilitations and replacements, four new bored stormwater crossings and the original culvert they replaced needed to be grouted. The tunnels ranged from 120″ down to 74″, for a total of 312CY, and the abandonment required 405CY.
The Challenge
Grout needed to meet the minimum strength requirements of the owner, and ideally needed to be light enough to facilitate single lift annular space grouting.
The Solution
CJGeo’s preconstruction team worked with the general contractor to design a grouting program which facilitated single lift abandonment of the original culvert, and single lift grouting of the four various annular space runs. CJGeo utilized onsite dry batching to generate 30lb/cuft CJFill Ultra Lightweight cellular concrete.
CJFill is a type of Low Density Controlled Low Strength Material, or LD-CLSM. The “low density” comes from using preformed foam, in this case Aerlite-iX, as a substitute for aggregate. This significantly reduces the unit weight, which exponentially increases pumpability. In this case, all 405 cubic yards of abandonment grout were placeable at once.
Because CJFill LD-CLSM is significantly lighter than water, each annular space grouting run was doable in a single lift. Filling each carrier pipe partially with water was all it took to facilitate this.
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CBBT Sheet Pile Pregrouting
The Job
This sheet pile pregrouting project is located in the Chesapeake Bay. The Chesapeake Bay Bridge Tunnel’s Parallel Thimble Shoal Tunnel Project is constructing a second tunnel parallel to the original to reduce traffic congestion. All launch & receiving work is on man-made islands in the Chesapeake Bay. The islands are dense with utilities, equipment and operations facilities associated with the existing tunnel, which is in continuous use.
The Challenge
During previous phases, installation of sheet piling for tunneling activities and other driven elements induced consolidation of the loose sandy fill on the islands. This was causing settlement of duct banks, pavements and other structures, which were remedied by CJGeo using polyurethane compaction grouting.
In this case, sheet piles had to be driven immediately adjacent to the roadway. This is in order to excavate the receiving pit for the tunnel boring machine. The construction team was concerned about inducing settlement of the adjacent roadway. They reached out to CJGeo about performing compaction grouting under the footing for the original tunnel’s portal wall. This was after the wall had been demolished down to grade.
The Solution
CJGeo performed compaction grouting utilizing an NSF-certified potable water contact plural component CJGrout 35NHV polyurethane grout. Cutoff criteria was 0.10 inches of movement of the foundation or adjacent roadway. Upon completion of the compaction grouting by CJGeo, sheet piling installation started. There was only nominal movement of the foundation and roadway.
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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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Spillway Bridge Grouting
The Job
This spillway bridge grouting project is located in Toano, Virginia. Toano is between Williamsburg and Richmond. Two DOT-maintained bridges crossing two privately owned dam spillways had to be closed because of extensive undermining of the spillways.
The undermining was allowing nearly all of the flow to happen below the spillway slabs. This caused large sinkholes to form adjacent to and under the roadway pavement. It also led to some settlement of the spillway slabs.
The Challenge
There was very little room to work–just under 4′ of clearance below the bridge beams. Also, the velocity of the water through the voids below the structure was quite high.
The Solution
CJGeo proposed a combination of plural component polyurethane grouting to address the water flows and voids, and hydrophobic chemical grout placed directly into cracks. A single CJGeo grouting crew was able to complete the repairs in a day (roughly 2500sqft of work, and approximately 4500lbs of CJGrout 35NHV61 polyurethane, plus 30 gallons of hydrophobic chemical grout). Dye testing during and after the grouting work confirmed that no more leaks were present under or around the spillway structures.
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Facing a similar challenge to this spillway bridge grouting 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.
