Project Holly Neck

A quick, beautiful, top-quality job.

By Leslie Lichtenberg

The Holly Neck wet-well pumping station in Middle River, Md., stands as a model for the ease, efficiency and cost savings generated when using precast concrete products over conventional alternatives. The new sewage pumping station, a project of the Baltimore County Department of Public Works, converted a waterfront community of 140 homes from septic to public sewer. The station utilized a concrete panel form construction to create a customized 17-foot, 10-inch by 8-foot, 6-inch product that addressed a variety of installation and construction issues.

Following the excavation of a 20-foot hole, the precast concrete pumping station was set in one day, a benefit over cast-in-place concrete which allowed contractors additional time to stabilize and backfill the hole and coordinate piping and hookup.

"The big advantage is in the installation," says Nancy Mayer, president of Mayer Brothers, Inc., in Elkridge, Md. "The general contractor never likes leaving a hole open any longer than necessary; with precast, we were in and out of there quickly," she adds.

"Working from the bottom section up, the precast pumping station was 'match cast' to ensure a perfect fit in the joints and to avoid any pipe penetrations," says Mayer. The 43,000-pound base was topped with a 28,700-pound riser section, and an 11,000-pound top, complete with an aluminum hatch door. The units were sealed, assembled and sealed again to prevent interior water penetration.

A unique feature of the Holly Neck wastewater system was the construction of an aboveground station to house the vacuum-assisted pumps. A departure from the more traditional method of mounting the pumping station on top of a manhole, the project was a first of Baltimore County.

"Public works went the extra mile on this project by including inside pump housing," explains the general contractor on the project, Bill Lipinski of Lee Foundation Co., Inc. "With the quick turnaround on the installation of the precast box, we were able to backfill immediately and build the masonry structure on top."

"Baltimore County was accustomed to building these stations a certain way," explains Rob Sell, project manager for McCrone, Inc., the engineers on the project. "Typically, they would feature a cast-in-place wet well, which was poured and tied to the floor. Using precast in the Holly Neck project required expansion anchors to attach the unit, but the county still managed to save money on the project overall."

Ease of installation and labor efficiency translated to cost savings on the Holly Neck station by significantly reducing the amount of coordination and fieldwork required by the contractor.

Earlier sewage pumping stations designed with cast-in-place products required labor-intensive excavation, monitoring and construction. In addition, efforts to complete such projects expeditiously have often been hampered when site conditions are problematic or weather turns severe. Alternatively, precast concrete promotes cost effectiveness by using a "complete" product that can be customized to meet specific project needs.

"Generally, we can produce a higher quality product under controlled circumstances than on-site," says the precast manufacturer, adding that optimizing the size and specifications of a factory-sealed structure also saves time and money.

With the Holly Neck station, the costs associated with delivery and installation of precast sections were offset by savings in time and labor. Other potential obstacles, including the small site and busy street where it was located, and the required installation of expansion anchors to attach the wet well to the floor, did not interfere with its timely and under-budget completion. Overall, Baltimore County saved an estimated $15,000 to $20,000 on the $380,000 project by using precast concrete instead of other materials.

All parties involved in the Holly Neck wet-well pumping station agree that precast was a primary contributor to the overall quality and efficiency of the project.

"As a builder of these types of stations for more than 48 years, I am always impressed by the quality and value precast concrete adds to the job," says Lipinski. "The Holly Neck project was not an exception - it was a very quick, beautiful, top-quality job."

Project Profile

Project: Holly Neck Wet Well Pumping Station, Middle River, Md.

Owner: Baltimore County Department of Public Works

Engineers: McCrone, Inc.

General Contractor: Lee Foundation Co., Inc.

Precast Manufacturer: Mayer Brothers, Inc., Elkridge, Md.

MD SHA
Approved Plant
Baltimore City, Howard County WBE