Fairfax, VA., May 18, 2017: Vogel Bros. Building Co., a utility contractor based in Lakeland, Florida, was recently selected by fellow NUCA contractor and associate members as the Water/Sewage Treatment Plant category winner in NUCA’s first national Top Jobs Competition—NUCA’s annual recognition program for premier utility construction and excavation projects. The competition recognizes companies that have completed difficult projects with innovation and efficiency with outstanding results.
The project required a complete rehabilitation of the Krause Street Wastewater Pumping Station, located in the middle of downtown Tampa—underneath the Cross Town Expressway between the Tampa Convention Center and the Hillsborough River. The rehabilitation revolved around the removal and installation of four new VFD controlled 400 hp fully immersible vertical centrifugal sewage pumps. In addition, the project included all new electrical and control gear, full rehabilitation of the wetwell, and replacement of all piping and valves including four 24” pneumatically controlled plug check valves. To allow the work to be completed, the entire station had to be bypassed for five months. The twelve-pump bypass system capable of a peak flow of 65 MGD was provided by fellow NUCA member Godwin Pumps. Several of the manholes the bypass pumps had to draw from were located in the middle of Ashley Drive. Ashley Drive was closed to thru traffic, but patrons exiting the Convention Center required a single lane for the duration of the project. The bypass system point of connection was a new 54” X 36” hot tap on a 30-year-old PCCP line. This line was located in an encasement 10 ft. from the outer wall of the Tampa Convention Center and 10 ft. from the foundation supports for the Tampa Crosstown Expressway. This excavation required two 3-sided guide frame system provided by Trench Plate Rental Co. to allow for the installation of the tapping saddle, valve, and hot tap.
Project Challenges and Solutions
The project’s biggest challenge came at its completion. Video logs of the completed wetwell indicated the influent line was deteriorated. This posed an immediate threat to pedestrians using the city’s Riverwalk. An emergency plan was developed to modify the existing bypass system to go further upstream to allow access to the influent line. The upstream manhole was on the other side of the Hillsborough River, which meant that approximately 18 MGD had to be pumped across the River. Following a bathymetric survey it was determined two 24” HDPE lines could provide enough flow while still allowing 8 ft. of draft down the middle of the channel when sunk in place. Fifteen 900-lbs. concrete ballast were attached to each pipe to sink them in place. The time required to float the 600 +/- ft. of each pipe across the river, connect them, and sink them was approximately eight hours. Therefore, the bypass installation had to be completed at night and the river had to be closed to all traffic. The entire process had to be permitted and approved by the Coast Guard. The emergency repair was designed, permitted, and completed within 8 weeks of being discovered.
Key Subcontractors and Equipment/Material Suppliers
The subcontractors included: Xylem Dewatering Solutions/ Godwin Pumps of America (installed bypass system); Trench Plate Rental Co. (supplied the guide frame system); and Midcoast Marine Group, LLC (performed marine work required to install bypass lines across river).
Benefits to the Client and Community
The Krause Master Pump Station collects flows from the southwestern portion of downtown Tampa and Davis Island. Each of those areas includes many commercial establishments that cannot afford to ever lose functionality. This project allowed for the continued use of the pump station that has been in operation in the same location for 70+ years. The new design of the station now allows for its continued use even during a natural disaster when the river could reach its 100-year-flood level. A specialized metal platform was built inside the station to raise all electrical gear above the 100-year-flood level. All electrical components below the flood level, including the pump motors were designed to remain fully immersed for up to 72 hours. These added precautions should provide a sense of security for the city of Tampa staff and their customers.
A group of independent judges selected the Vogel Bros. Krause Street Master Pump Station project as one of three finalists in the Water/ Sewage Treatment Plant category—one of the ten construction project categories contractors could enter. Convention attendees selected the Vogel Bros. project as the winner of the Water/Sewage Treatment Plant category.
The National Utility Contractors Association (NUCA) is the largest national trade association working solely for the utility and excavation industry. NUCA represents roughly 1,600 contractors, manufacturers, suppliers, and service providers that provide the workforce, equipment, materials and services that build and maintain the nation’s network of water, sewer, gas, electric, and telecommunications infrastructure.
As posted by the National Utility Contractors Association (NUCA), May 19, 2017