St. Barnabas 2.5 MG Composite Elevated Water Tank Demolition and Replacement

Key Accomplishments

Johnston Construction Company

• Furnished, installed and maintained the project's required erosion and sediment-control measures throughout JCC's construction operations. Controls were required to be established before major earth disturbance and maintained until final stabilization and restoration were complete.
• Performed site clearing and grubbing within JCC's work limits, including removal and disposal of clearing debris and unsuitable materials that could not be incorporated into permanent construction.
• Managed existing topsoil stockpiles for reuse during final restoration and furnished supplemental topsoil where required.
• Furnished and maintained required tree-protection measures and construction-area controls associated with the project's environmental and site-protection requirements.
• Performed extensive excavation, trenching, bedding, backfilling and compaction required for installation of new water mains, valve vaults, overflow piping and storm-drainage facilities.
• Furnished and installed major portions of the project's large-diameter water-distribution system, consisting primarily of 24-inch and 20-inch water-main piping together with associated fittings, valves and appurtenances.
• Installed the designated 24-inch water-main alignment, including associated fittings and appurtenances connecting the new elevated-tank facilities with the existing WSSC distribution infrastructure.
• Installed associated hydrant improvements within JCC's water-main construction limits.
• Installed the project's 20-inch water-main piping extending toward the new elevated-tank foundation, including coordination of the required transition and flexible connection at the tank interface.
• Furnished and installed the water-main segment serving the new altitude valve vault and bypass piping system, providing an important component of the hydraulic control system serving the replacement elevated tank.
• Constructed the project's Horizontal Isolation Valve Vault, including the associated piping, valves and appurtenances required for system isolation and operation.
• Installed additional sections of 20-inch water main necessary to complete the interconnected underground piping system serving the new tank site.

Concrete Services Division

• Performed the specialized structural concrete forming, placement and finishing package for major underground water-system structures associated with the St. Barnabas Elevated Water Tank replacement project.
• Constructed the concrete components of the Altitude Valve Vault, including the slab, walls and supported top slab required for the underground valve facility.
• Constructed the concrete Flow Control Valve Vault, including slab-on-grade, vertical walls and supported top-slab concrete.
• Constructed the concrete Isolation Valve Vault, providing the structural concrete enclosure required for the project's isolation-valve system.
• Furnished and erected extensive concrete formwork for slabs-on-grade, straight walls, supported slabs and bulkheads associated with the vault structures.
• Stripped and removed formwork following completion of concrete placements and achievement of the required curing conditions.
• Performed concrete placement operations for slabs-on-grade, vault walls and supported slabs in coordination with the overall utility and piping construction sequence.
• Performed float and screed finishing of horizontal concrete surfaces to achieve the required elevations and finished surfaces.
• Completed pointing and patching operations after form removal to address surface imperfections and produce finished structural concrete surfaces.
• Performed specified bag-rub finishing on designated exposed concrete surfaces.
• Provided labor and associated supplies for concrete curing, protecting completed placements during strength development.
• Installed vapor-barrier and waterstop systems at required concrete locations to support the watertight performance of the underground structures.
• Performed labor associated with installation of reinforcing steel and welded-wire mesh incorporated into the structural concrete work. Where reinforcing materials were provided by others, CSD coordinated and performed the required placement labor as defined by its subcontract.
• Installed reinforcing-steel supports and coordinated placement around embedded items, wall penetrations and piping openings before concrete placement.