St. Marks Pumping Station No. 6 Upgrade

Key Accomplishments

Johnston Construction Company

• JCC’s scope included sequencing and coordinating construction, bypass pumping, demolition, utility coordination, sitework, process piping, pumping equipment, grinder equipment, sluice gates, generator systems, control panels, instrumentation, startup, testing, training, and final turnover.
• The work required bypass pumping to allow the existing pumping station to be taken offline while construction and installation work was completed.
• The pumping station could not be placed online until electrical system modifications, main power feed, motor control centers, emergency generator, controls, pump testing, and startup requirements were completed and verified.
• The project required successful pumping station operation, startup, system demonstration testing, functional testing, owner training, O&M manuals, as-built documentation, warranties, and closeout.
• Johnston Construction Company completed the St. Mark’s Pump Station No. 6 Upgrade for Charles County, Maryland. The project was designed by GHD Inc. and consisted of construction and upgrade work for the St. Mark’s pumping station under a public-bid fixed-price contract.
• The work included construction, coordination, and installation of the materials and equipment shown in the contract drawings and specifications. JCC was responsible for the construction sequence, coordination of work, temporary systems, bypass pumping, electrical connections, temporary piping, testing, startup, and turnover of the completed pumping station.
• A major part of the project included maintaining pumping station operations during construction. JCC provided bypass pumping so the existing pumping station could be taken offline and work could be completed on multiple project components. The bypass pumping system included temporary piping, valves, pipe plugs, pumping equipment, controls, emergency power provisions, alarm/dialer requirements, and coordination with the Owner.
• JCC also coordinated installation and startup of major equipment, including sluice gates, submersible pumps, grinders, power ventilators, flow meter, packaged engine generator system, pump control panel, and pumping station SSRV control panels. Equipment installation required manufacturer’s field services, field testing, final acceptance testing, training, performance affidavits, shop testing, and operation and maintenance documentation.
• The project required careful coordination with Charles County operations, local utility providers, regulatory agencies, and affected site users. JCC coordinated scheduling, submittals, field engineering, inspections, traffic and site controls, temporary facilities, erosion and sediment control, dewatering, utility protection, security, housekeeping, and site restoration.
• Startup and testing included preliminary field testing, functional testing, pump station controls programming coordination, system demonstration testing, startup using actual service conditions, training, and final delivery of the completed system to the Owner. The completed pumping station was required to operate successfully before temporary systems could be removed and the project could be turned over.
• The Project Was Completed On 16th January, 2019

Concrete Services Division

• Concrete Services Division performed the reinforced-concrete work supporting the upgrade of St. Marks Pumping Station No. 6 in Charles County, Maryland.
• CSD furnished the labor, forming systems, reinforcing accessories, placement equipment, tools, and concrete-finishing services required for the pumping-station structures.
• The company formed, placed, finished, and cured reinforced-concrete foundations, walls, slabs, pads, and other structural and equipment-support elements.
• CSD constructed concrete components associated with the pumping-station wet well, station building, process equipment, piping supports, and operational improvements.
• The work included reinforced-concrete walls with specified architectural rub-wall finishes.
• CSD installed slab-on-grade concrete, elevated or structural slabs, equipment housekeeping pads, and equipment foundations required by the project.
• The company coordinated reinforcing-steel installation, concrete embedments, waterstops, dowels, anchor bolts, pipe penetrations, sleeves, and equipment openings with JCC and the other project trades.
• CSD furnished concrete formwork and forming accessories required to achieve the specified structure dimensions, elevations, finishes, and tolerances.
• The company coordinated wall and slab placements with the wet-well construction, precast components, piping, pumps, grinders, sluice gates, electrical equipment, and mechanical systems.
• CSD performed concrete placement using approved mix designs and coordinated inspection and testing requirements for slump, temperature, air content, unit weight, and compressive strength.
• The company consolidated concrete around reinforcing steel, embedded components, waterstops, sleeves, and anchor assemblies to produce complete and durable structural placements.
• CSD provided concrete curing and protection in accordance with the project requirements, including provisions for hot-weather and cold-weather placement conditions.
• The work included non-shrink grout beneath equipment bases and other components requiring full bearing and load transfer.
• CSD installed drilled and adhesively anchored dowels and bolts where required for connections to existing or previously placed concrete.