Apr 07, 2020

Storm Water System: A Concrete Solution

This article originally appeared in Storm Water Solutions March/April 2020 issue as "A Concrete Solution"

concrete solution

The recent restoration of a 2.2-mile section of historic McGregor Boulevard in the city of Fort Myers, Florida, finally gave residents the long-awaited relief to congestion problems plaguing the area for years. Most Fort Myers residents have been impacted by the regular lane closures and emergency construction on this route over the past decade and a half due to failures with the existing storm water system.

Fortunately, the city of Fort Myers assembled a team of experts to devise and execute a plan alongside the Florida Department of Transportation (FDOT) to permanently overhaul the storm water system by replacing the failing plastic pipe with structural concrete pipe.

Fort Myers receives 54 inches of precipitation annually, which is more than 20 inches above the annual (Continental) U.S. average. Not to mention that during major storm events, Fort Myers can be drowned by a large volume of precipitation in a short period of time. These factors required the installation of a new rugged and dependable storm water system to effectively manage any weather events and minimize travel disruptions on McGregor Boulevard, considered "The Gateway to Fort Myers," according to Public Works Director Richard Moulton. 

The Drainage Problem

When McGregor Boulevard was originally constructed more than 100 years ago, the only semblance of a road in the area was a slim strip of graded, crushed shell down the middle of First Street. That all changed with the addition of McGregor Boulevard to Fort Myer’s transportation landscape, which today is lined with majestic Royal Palm Trees that exemplify the moniker, “City of Palms”. 

Completed in 1915 for an estimated modern-day-equivalent of $300 million, McGregor Boulevard enjoyed varying degrees of maintenance and upgrades over the years by the FDOT. 

In 1999, when the FDOT transferred ownership of McGregor Boulevard within the Fort Myers city limits, the pipe used in the original storm water system between Colonial Boulevard and Poinciana Avenue was replaced with corrugated high-density polyethylene (HDPE) plastic pipe.

Post-installation inspection video records starting in 2000 revealed immediate and future structural distress in the storm water system. As a result, the city had to repair and replace numerous sections of the HDPE pipe and subsiding pavement over the next decade and a half. This ongoing time-consuming exercise was costly to the city and disruptive to its residence. 

  • HDPE plastic pipe

water pipe

storm water
 Picture 1 (top). In 1999, the original pipe was replaced with HDPE plastic pipe. 

 2. Instead of periodic repairs, the entire pipe system was replaced.

 3. Fort Myers receives 54 inches of precipitation a year. 

A Concrete Solution

Spurred by a series of super-tidal events that surcharged the storm water system in the coastal impacted zones, city officials ultimately decided to replace the entire plastic pipe system rather than continue with the periodic repairs. It is believed that the surcharged weather events exacerbated the compromised pipe sections leading to accelerated failures of the pipe embedment and more significant pavement subsidence. What would have been a more manageable situation became more cavernous due to the surcharged events.

Through successful coordination with the FDOT, officials of Fort Myers found a way to secure funding and restore the infrastructure, officially known as the McGregor Boulevard Flexible Pavement Restoration. The city designed the $5.4 million project in-house led by Saeed Kazemi, P.E., who served as engineer of record on the project. Underground preparation was performed by Andrews’ Site Work and the installation of Rinker Materials concrete pipe was facilitated by Wright Construction Group. Construction engineering inspection (CEI) services were performed by local engineer Paul Wingard, P.E. (KCCS Construction Services). 

The engineering plans directed the removal and disposal of 11,672 feet of existing HDPE before being replaced with 232 feet of elliptical reinforced concrete pipe (ERCP) and 11,440 feet of 18-inch through 30-inch reinforced concrete pipe (RCP). In addition to replacing the HDPE, the project required the milling and resurfacing of 51,400 square yards of asphalt, the installation of 18,350 square yards of pavement base and subgrade material, 8,600 yards of asphalt and 350 tons of asphalt leveling course.

During construction, the underground contractor noted they discovered in many areas it was apparent the previous construction did not even bother to relocate utilities as there was HDPE drainage pipe with bore holes right through it. Additionally, the HDPE drainage pipe was bent extremely outside of allowable tolerances around impediments, which caused the pipe to restrict storm water flow. 

The contractor also found the existing HDPE drainage pipe to be crushed underneath the pavement due to traffic loading that cannot be supported by the pipe itself. This is evident at the ground surface level by the many dips and depressions along the roadway, which prompted the many years of maintenance and ultimately the need to completely reconstruct McGregor Boulevard. 

McGregor Boulevard Flexible Pavement Restoration demonstrates a unified effort between FDOT and Fort Myers on behalf of the city's residents. 

As construction concluded, one local business owner along McGregor Boulevard noted the project has helped increase traffic while limiting congestion. Beyond the much-appreciated benefits to area residents, the healthy storm water system on McGregor Boulevard also ensures visitors are welcomed to the “city of Palms” regardless of weather conditions.  

About the author

Sarah Matin is regional engineer for Rinker Materials. Matin can be reached at [email protected].