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FEATURED PROJECTS

RECENT PROJECTS

PAST PROJECTS

“All MERCO projects are vetted through a highly detailed site logistics and planning process to ensure the most efficient approach to performing the work is implemented.” STEPHEN MERGENTIME, PE PRESIDENT

FEATURED PROJECT

project: Bald Top Road Soil Nailing Project

Owner: Mahoning Township

Project Start: MAY 2021

Project Completion: August 2021

Bald Top Road in Mahoning Township, Pennsylvania, suffered a major slope and pavement failure along 1,200 linear feet of roadway. Merco was contracted to conduct emergency repairs and stabilization to reopen both travel lanes of the roadway. Difficult site conditions required the use of a custom drilling platform to allow safe operator and work access to the slope below the failure. Utilizing this Merco designed drill rig, Merco was able to install soil nails along the upper 10’ of the failed slope after initial clearing efforts, followed by roadway repaving and drainage improvements to prevent further undermining of the slope. All repair work was completed in three months, on schedule, allowing Mahoning Township to re-open both lanes of Bald Top Road.
FEATURED & RECENT PROJECTS

FEATURED PROJECT

project: MD 135 Emergency Rock Slope Repair
Owner: Maryland State Highway Administration
Project Start: 1/16/2016

Project Completion: 7/15/2016

This Merco Design-Build Emergency repair project stabilized a rock ledge overhanging Maryland Route 135 active roadway. This project involved the design of a repair system, blasting the overhanging rock ledge, and the use of rock bolts, shotcrete, and 40,000 sf of wire mesh to stabilize the slope. Additionally, Merco performed drainage improvements and road reconstruction paving, as well as implementing a Maintenance Protection of Traffic (MPT) program. Merco designed, mobilized and completed the Project in 6 months.
FEATURED & RECENT PROJECTS
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FEATURED PROJECT

project: Blue Ridge Tunnel Rehabilitation

Owner: Nelson County, VA

Project Start: 12/2018

Project Completion: 10/2019

Merco was contracted to perform a complete rehabilitation of the historic Blue Ridge (Crozet) Railroad Tunnel, for the purpose of converting the tunnel into a pedestrian trail to be included into the Blue Ridge Trail System. The Blue Ridge Tunnel was originally constructed in the 1850’s by the Blue Ridge Railroad. At 4,237 feet long, it was once the longest railroad tunnel in North America. The work included rehabilitation of the existing brick liner with steel fiber reinforced shotcrete and consolidation grouting to fill voids throughout the brick liner sections. In the unlined sections rock bolts and shotcrete were used to stabilize the tunnel. The removal of two 25-foot-thick reinforced concrete bulkheads was also required for the rehabilitation efforts. This work was performed by conventional drill and blast methods. Controlled precision blasting was performed to enable operations to be maintained in the adjacent tunnel. Portal reconstruction and drainage improvements throughout the tunnel and approaches was also completed. In 2020, the rehabilitated tunnel was opened to visitors as part of the Blue Ridge Trail System.
FEATURED & RECENT PROJECTS
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FEATURED PROJECT

project: Mount Morris Dam North Tunnel Repair
Owner: U.S. Army Corps of Engineers – Buffalo District
Project Start: 3/1/2023

Project Completion: 8/15/2023

In early 2023, the U.S. Army Corps of Engineers (USACE) identified stress fractures in a small adit tunnel at Mt. Morris Dam; an important flood control dam on the Genesee River in upstate New York. Merco was contracted to lead the rehabilitation and stabilization project. After initial planning, it became evident that the steel sets and concrete approach to reinforcing the tunnel initially proposed by the USACE was not possible due to extremely difficult access to the work area. The adit tunnel was only accessible through the dam’s lower gallery. A long narrow corridor the length of the dam and several stair wells would need to be traversed to manually carry all equipment and materials to the actual work site. This would have made it impossible to meet the project’s budgetary and schedule constraints. Merco instead utilized a long-line helicopter to mobilize materials and equipment to the actual work area saving weeks of mobilization time and costs. Further, Merco proposed and implemented a novel repair method utilizing carbon fiber wrap technology to stabilize the tunnel while maintaining the original tunnel opening size, working closely with Kilduff Underground Engineering to design the unique repairs. Additionally, Merco utilized chemical grout injection to fill cracks and voids behind the tunnel liner. After the tunnel was stabilized, a new concrete façade was poured along with a brand-new tunnel entrance door to repair the exterior concrete work, maintaining the original look of the dam, originally constructed in 1952.
FEATURED & RECENT PROJECTS
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RECENT PROJECT

project: Delaware River Route 78 Emergency Rock Anchor Installation
The work involved the emergency stabilization of the Route 78 Toll Bridge east abutment due to an adjacent slope failure. Merco crews mobilized and installed high-capacity rock anchors through the existing abutment foundation. Due to limited site access the anchors were installed with a Merco designed drill feed at heights of up to 80 feet above grade. All work was performed below the bridge structure to enable the free flow of traffic through the work zone.
FEATURED & RECENT PROJECTS
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RECENT PROJECT

project: Yards Creek Intake Tunnel Closure

As a key component to the Yards Creek hydroelectric upgrade project for First Energy, Merco was selected to perform specialty work along the intake channel and within the intake tunnel to the power plant. The rock slopes adjacent to the channel were scaled of all loose material then covered with rockfall drape system for worker protection at the base of the channel. The existing tunnel and entrance gallery were also stabilized utilizing #14 Grade 150 DCP Rock Anchors. Merco performed all work during scheduled outages.
FEATURED & RECENT PROJECTS
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RECENT PROJECT

project: Legislative Plaza Motlow Tunnel Demolition

Skanska USA Building selected Merco for the demolition of the Motlow Tunnel, part of Skanska’s contract to renovate and rebuild the Legislative Plaza and War Memorial Building in Nashville Tennessee. Demolishing the severely deteriorated tunnel required the excavation of at least 8 feet of surrounding rock, which was impractical to remove mechanically given its proximity to government and commercial structures in downtown Nashville. Merco met this challenge with precision blasting utilizing Dyno Nobel’s novel Digishot digital detonation system, enabling Merco to create precise and controlled shot designs to solve access, vibration, and airblast limitations, ensuring safety and compliance with high-tech seismographic monitoring from multiple locations.
FEATURED & RECENT PROJECTS
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RECENT PROJECT

project: 1300 Manhattan Ave Rock Slope Stabilization
In October 2022, Merco was contracted to stabilize a fractured slope at 1300 Manhattan Avenue in Union City, New Jersey. Due to previous excavation and site work, the rock slope around the proposed apartment building had become fracture and highly dangerous to work around. Merco worked to initially scale the slopes and remove any loose rock in immediate danger of falling. After scaling efforts, the Merco crew drilled and installed over 100 soil nails and rock anchors in combination with Maccaferri’s double twist netting system in order to further protect the site from future rock falls.
FEATURED & RECENT PROJECTS
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RECENT PROJECT

project: Great Hill Tunnel and Pipeline Restoration

This emergency restoration and repair project was required due to a tunnel liner failure in the existing raw water supply to the water treatment plant in North Branford, serving the city of New Haven, CT. Merco installed a bypass pumping system to enable dewatering of the tunnel while maintaining the raw water supply. The existing tunnel was a 3,500 LF long concrete-lined rock tunnel starting at an intake structure within Lake Gaillard and extending to the water treatment plant. Merco installed tunnel ventilation system and utilities through the intake structure and a personnel access shaft at the downstream end of the tunnel. The restoration work included chemical cutoff grouting for water infiltration, liner repair patching, shotcrete liner repair, and extensive cement grouting. The project was performed working (2) 12-hour shifts, 6 days a week and was completed in 3 months.
FEATURED & RECENT PROJECTS

Metro North Emergency Rock Slope Remediation

Highland Mills, NY

Merco removed three large unstable rock slope masses, up to 600 CY in size. Other work included improving site access, tree and vegetative clearing, scaling of entire rock slope, and installation of rock slope stabilization and rock fall mitigation devices, including 15’ to 30’ tensioned rock bolts and composite cable mesh. All work, except for large rock mass removals, was completed under live railroad track conditions within 20 feet of active track, which was protected during all work operations. Work was completed ahead of schedule with no railroad impacts due to Merco’s work.

Rt. 78 Rockfall Mitigation, MP 44.75

Berkeley Heights, NJ

This rock slope stabilization and rockfall mitigation project was 1,000 LF with slope heights up to 70’. Over 600 CY of clearing and scaling was performed before installation of an average of 6” thick (331 CY total) Shotcrete by installing 150 5’6” Rock Dowels to pin shotcrete to the slope and installation of 225 perforated rock drains. All shotcrete was manually installed with experienced nozzlemen from an aerial manlift. All drilling was installed from aerial manlifts using Merco Fabricated Drill Feeds. 968 LF of 8’ tall Rock Catch Fence was installed. All work was self-performed by Merco.

Bergen Railroad Tunnel Rehabilitation Program

This major tunnel enlargement and rehabilitation project was complicated by the almost constant flow of train traffic carrying over 40,000 railroad commuters to and from New York City each day.
MERCO had to safely maintain and protect the trains traveling through the South Tunnel from the blasting and other construction activities they were performing in the North Tunnel.

Cameron Run Stormwater Tunnel Rehabilitation

MERCO’s rehabilitation of seven 20-foot diameter stormwater tunnels through the CSX railroad embankment presented numerous challenges. Over the years the existing tunnels had become severely deformed. Previous attempts at grout injection repairs had little beneficial effect, and in many cases actually made matters worse. Beginning in 1994 wooden props were installed in an effort to further support the deformed tubes. MERCO’s approach to the rehabilitation process was based on optimizing the existing support structures. The existing steel liner plate tunnels were pushed back into oval shape, new steel supports were installed throughout, and the tubes were relined with a minimum of 6” thickness of steel fiber reinforced shotcrete. MERCO performed all work under live track conditions.

Otisville Tunnel Rehabilitation

This project involved stabilization of 924 LF of exposed rock in this active railroad tunnel operated by Metro North Railroad. Included was extensive cleaning of the tunnel walls, capturing and off-site testing of all wash water for environmental impacts, thorough rock scaling of sidewalls and crown, installation of rock drains, strip drains, and dental shotcrete to stabilize overhanging rock slabs, as well as installation of steel fiber reinforced shotcrete. All work was performed during limited track outages and was performed with hi-rail equipment. Merco utilized a Normet shotcrete robot to facilitate installation. All work was performed during specified outage time frames and was completed with no delays to the railroad.

Rt. 5 Rock Slope Stabilization

Edgewater, NJ

This NJDOT rock slope stabilization and rockfall mitigation project was 1,600 LF with slope heights up to 100’. Nearly 2,000 CY of material was removed from the slopes, which were then scaled and partially stabilized with rock bolts. Over 400 Rock Dowels, 3,850 SY of Rockfall Drape Net, 2000 SY of Wire Mesh Slope Protection, 25 CY of Dental Shotcrete, over 3,300 SY of 4” Shotcrete Treatment, two Fault Zone Treatments including bolting, drainage infrastructure, and nearly 600 CY of shotcrete were used. Merco self-performed all shotcreting and assisted their subcontractor on scaling, bolting, and mesh operations.

Shellpot Bridge

Wilmington, DE

MERCO completely rehabilitated this historic truss swing-span bridge and its approaches. Work included demolition of the existing pier caps and piles replacing them with concrete piles and precast pier caps. The existing girder stringers were refurbished, we removed and refurbished the 260-foot swing span, and refurbished and replaced all the mechanical and electrical operating machinery. Additionally, the center pivot pier, rest piers and abutments were reconstructed. The project was constructed under limited schedule considerations.

Stone Harbor Boulevard Bridge

MERCO constructed a new 7-span, pre-stressed concrete box beam bridge supported on 20” square prestressed, 70 foot long concrete piles and cast-in-place concrete pile caps. This phased construction consisted of installation, maintenance, and removal of a 12’ wide Merco designed temporary bridge structure and traffic control system.

Union Pacific Clayton Bridge Removal

This project involved the complete removal and demolition of an existing 5-span steel plate girder railroad swing bridge over the Tensas River. Merco completely removed the 5 heavily reinforced concrete piers and 2 abutments utilizing controlled explosives demolition techniques. All work was performed from barge mounted equipment.