Fast 14, USA
Eliminator waterproofs 14 bridges in 10 weekends on Fast 14 project
The Fast 14 project was well named – in just ten weeks, from June to August 2011, the Massachusetts Department of Transportation (Mass DOT) replaced fourteen bridges on the busy I-93 (Interstate 93) near Boston. The work would have normally taken over four years, with drivers having to endure the resulting long-term traffic disruptions and consequential costs to the environment and the economy.
In the summer of 2010 failure of a bridge deck on I-93 disrupted traffic for two days. Upon inspection on this and other structures, it was found that the concrete decking and steel beams were failing on fourteen aging bridges. Faced with the potential economic and environmental impacts of years of traffic jams, Mass DOT decided to reduce the disruption to a minimum, utilising the recommended methods of the Federal Highways Accelerated Bridge Construction Programme.
Massachusetts Department of Transportation
J F White
Chapman Waterproofing Inc.
- Fast 14, Medford
Stirling Lloyd’s Eliminator system was chosen to waterproof the fourteen bridges as it met the DOT’s requirements for speed, durability and quality. Eliminator has a proven track record of over twenty-five years on US bridges. Its fast curing, highly durable properties allows the membrane to be overcoated in 40 minutes and trafficked, prior to paving by regular traffic without damage to the membrane, so avoiding unnecessary traffic disruption and keeping traffic moving, making it the best choice for this fast-track project.
On a weekend after the Friday evening rush hour, crews changed the traffic flow on I-93, dismantled the bridge to be treated, brought in new prefabricated concrete bridge panels, joined them together with rapid setting concrete diaphragms and applied temporary road markings. The new bridge was opened in time for the Monday morning rush hour, so minimising disruption to local commuters.
On a following weekend, the waterproofing was installed. The deck was shotblasted to provide a clean laitance-free surface, followed by the application of the PAR1 primer. This sealed the deck and enhanced the adhesion of the subsequent Eliminator membrane to the deck.
Stirling Lloyd’s Eliminator membrane was spray applied in two light-coloured contrasting coats, which enabled the applicator to check the correct and complete coverage of the membrane, even when applied at night.
To provide a high friction skid-reducing surface, aggregate was broadcast into the second coat of the Eliminator membrane to provide a temporarily trafficable wearing surface.
Upon late inspection, the membrane suffered no damage by regular traffic. This method of working helped speed up the work and reduce costs, it also reduced the cost to the general economy caused by major traffic disruption and delays.
When possession could be taken again, the surface was brushed off, and Stirling Lloyd’s proprietary bond coat, was applied before the application of the asphalt wearing course.
Although the project was set up with demanding completion dates, the general contractor, J F White was successful in exceeding its project performance goals. Traffic delays and emissions from traffic jams occurred over two months instead of four years, minimising the economic and environmental impact of the complete replacement of the bridges. Stirling Lloyd’s highly durable Eliminator system contributed significantly to the time and cost savings on this project and will ensure reduced life-cycle costs and the long-term protection of the Fast 14 bridges.