The 2007 Kentucky Derby was one of the most emotional events in horseracing history. When the management at Suffolk Downs track realized they had a challenge to get the work done during the off-season and be open in time for the simulcast, they put together a team that could get the job done in time.

The thoroughbreds race at Suffolk Downs in East Boston, Mass., just a mile from Logan Airport. The live horseracing and simulcasting make it a popular destination in the area. When management discovered that site drainage work was required, they knew that the construction would have to be completed quickly. The track has been in operation since 1935, and would have to be ready for opening day of the live racing season and simulcast of the Kentucky Derby on May 5, 2007.

The Department of Conservation and Recreation’s Planning and Engineering Division funded and oversaw the contract for the $7 million project. The general contractor, Revoli Construction Co. Inc., of North Reading, Mass. and its subcontractors, completed the work. Hatch Mott MacDonald served as the engineering consultant.

The scope of the work included installation of approximately 2,000 feet of 96-inch diameter centrifugally cast, fiberglass reinforced, polymer mortar (CCFRPM) pipe supplied by Hobas Pipe USA of Houston. The pipe was placed as twin culverts at three different locations around the Suffolk Downs facility in Revere and East Boston. Two of the lines traveled directly under the racetrack surface with the third running under the main entrance road.

Installation

The 21-foot trench width at Suffolk Downs allowed for only a 2-foot clear space between the Hobas pipes and a 1 1/2-foot clear space to the trench wall.

“The pipe went together well, and was embedded with flowable fill and backfilled with select compacted materials to grade,” said Steve Pini, superintendent for the racetrack. “The surface work and track restoration began after Revoli reached grade.”

Phase one included restoring the hydraulic capacity of the drainage system at the two uppermost locations to restore hydraulic capacity and remove blockages. Phase two included replacing the downstream twin 60-inch diameter HDPE pipes with 96-inch CCFRPM pipes, as well as channel and lagoon dredging.

“The 60-inch HDPE pipes were a temporary emergency repair done a few years ago after the collapse of the existing 108-inch corrugated line,” said Pini. “The corrosion from the soils and tidal location cut through the corrugated pipe like a razor blade. We knew we would come back with a permanent fix.”

CCFRPM was the only material specified for the storm drainage improvement piping because of its resistance to corrosion, hydraulic capacity and abrasion resistance. Detailed material specification also included specifics on the interior surface of the pipe, requiring a 50-percent elongation on the resin used. This was required to achieve the necessary abrasion resistance. Proof of prior performance of the pipe product was required. A five-year history and a list of 500,000 feet of installed pipe were required with the submittal package. Since timing was critical, the project specifications included a guaranteed pipe delivery timeframe.

“Work can be performed only in the off-season for the track between Dec. 1, and March 1,” said Shawqi Alsarabi, the contractor’s president. “March 1, 2006, was the completion date for phase one, and March 1, 2007, was the completion date for phase two.” The tight schedule was caused by the fact that work involved removing and replacing a building and two sections of the track.

The pipe manufacturer worked with the contractor and designer to provide installation recommendations for the tricky twin barrel installation submerged in flowable fill by direct bury. The 21-foot trench width allowed for only a 2-foot clear space between pipes and a 1 1/2-foot clear space to the trench wall. The native soil material at the 12-foot cover depth had a constrained modulus of only 700 psi (SPT N=2 blows per foot minimum).

To combat the poor properties of native materials and minimize settlement, a flowable fill was specified for the embedment material. To increase its strength, the fill was allowed to develop before the cover material was placed. “We worked in a tight trench to minimize the amount of soil removed and to save on flowable fill,” said Alsarabi. “The 72-psi pipe stiffness ... performed well even in difficult conditions.”

Much of the work on the project was performed in a stormwater drainage channel, and was subject to storm conditions and fluctuations in water levels. The contractor was required to provide a means to work in the presence of water in the channel, storm events and tidal impacts.

Given the geography of the area, installers constantly battled the storm surge. “We had [an obstacle with] the tide gates during heavy rain and the high tide, which made our bypass ineffective during those events, especially during the second phase,” said Alsarabi. Even given the difficult conditions and quick timing, he added, “The pipe performed well.” PE