RIDOT’s Special Delivery of Iway Bridge May Earn National Award

Tue July 22, 2008 - Northeast Edition
James A. Merolla



Usually, you build a bridge from the ground up. But an innovative, dramatic delivery of a sectioned bridge after a 12-mi. (19.3 km) trip up river by the Rhode Island Department of Transportation (RIDOT) may win them a national award from a group representing transportation officials across the nation.

RIDOT has announced that the Iway project — the most expensive highway project in the state’s history — has earned national recognition for its unique approach in building the new Providence River Bridge by assembling it off site and “floating” it up Narragansett Bay to Providence.

In August 2006, thousands of Rhode Islanders lined up along miles of the Providence River to watch the centerpiece Iway bridge — now up and being crossed each day by thousands of motorists — be delivered by special barge from Quonset Point/Davisville to the capital city.

An assembly of barges and tugs towed the 4.9-million-lb. (2.2 million kg) bridge 12 mi. up Narragansett Bay in just three hours. In a single day, the skyline of Providence was transformed.

For this innovation, RIDOT has placed first among member DOTs in The Northeast Association of State Transportation Officials, which represents all six New England States, Delaware, the District of Columbia, Maryland, New Jersey, New York, Pennsylvania and the Canadian provinces of Ontario and Quebec. There will be three more regional competitions to determine finalists for the America’s Transportation Award from the American Association of State Highway and Transportation Officials (AASHTO).

The competition celebrates excellence in transportation projects throughout the country in the categories of On Time, On Budget and Innovative Management.

The latter of these, for which RIDOT was lauded, “recognizes new policies or procedures and creative transportation solutions that enhance the effective movement of people, goods and services; increase transportation efficiency and choices; improve safety, accessibility and aid traffic management; and enhance community life.”

This statement epitomizes the Iway project and RIDOT’s approach to construct the $610 million project as efficiently as possible. The new Providence River Bridge was no exception.

“The department is extremely proud of the Iway project and this recognition,” RIDOT Director Michael Lewis said. “The innovative approach in building the bridge offsite and floating it to Providence was the safest, most efficient means of constructing it. It was a great feat of engineering.”

Winning Entries

The 24 winning entries at the regional level will be submitted to the national competition with one winner selected from each category for both large (more than $200 million) and small (less than $200 million) projects. One winner will be selected in each category.

In addition, a Grand Prize will be awarded from those final six entries. A substantial monetary award will be presented to the winning State Department of Transportation for donation to a university of its choice to assist a student pursuing a graduate degree in transportation.

This will likely help the University of Rhode Island, should RIDOT win, as DOT works closely with that college’s civil engineers.

In August 2006, RIDOT orchestrated a series of events to install the 400-ft. (121.9 m) center span for the bridge. The bridge float captured the attention of Rhode Islanders from all over the state who watched on television and read in newspapers about the entire process of raising the bridge, placing it on Self-Propelled Modular Transporters, rolling it onto two large barges, and floating it up the bay.

The day of the float, thousands of people lined the shores of the bay to witness history and watch the bridge sail by. The bridge float also attracted the attention of the History Channel, which produced a documentary on the Iway for its “Mega Movers” series.

The arch bridge is the most prominent part of the agency’s biggest project, the relocation of a section of Route 195 and its interchange with Route 95. In early June, RIDOT closed the old Exit 20 off Route 95 and the IWAY became the permanent way to avoid a contested section of Providence traffic from the south, heading east.

Convention Be Damned

Clearly, the conventional way to build a bridge is to assemble it in place, piece by piece. That’s how the rest of the new bridge, much simpler than the arch section, was put together.

But, according to engineers, assembling a bridge in place is problematic because most of the work has to be done from barges. The Providence River Bridge’s design, meanwhile, yielded a single unit that could be picked up and moved intact.

Cardi Corp. of Rhode Island, the general contractor, chose to build at Pier 2 at Quonset Point/Davisville — a large, flat, solid area that would support the bridge during assembly and allow Cardi to maneuver its cranes and other equipment surrounding it.

The mover was Mammoet Corp. of the Netherlands, which specializes in moving very large, heavy objects like offshore oil-drilling rigs.

The bridge, which DOT said is unusual because it has three arches instead of two, was designed by William D. Warner Architects and engineered by Maguire Associates.

“I had the pleasure to be present for this event, viewing the arrival of the bridge from the vantage point of the Fox Point Hurricane Barrier, along with many other officials who had come to witness this extraordinary feat,” said Providence Mayor David Cicilline in a letter congratulating DOT for its nomination. “In addition to sharing our appreciation of the tremendous expertise on display in the dramatic conveying of the span to the Providence Harbor, many remarked on the graceful design of the structure and the manner in which it complements the Providence skyline.

“Added to this is the welcome opportunity we [now] have, due to the impending dismantling of the older I-195 span across the water, to open up 19 acres of prime waterfront land for parks and river walks, unifying the aesthetics of the west side of the river with that of the east, where extensive and superb development has already been completed,” added Cicilline. “In sum, the Iway project and its centerpiece — the Iway bridge and the careful planning and expert care which brought it to Providence — is a splendid achievement that, in my considered opinion, makes RIDOT a strong candidate in a bid to receive an Innovative Management Award from AASHTO.”

The 1,250-ft. (381 m) bridge over the Providence River is located south of the current alignment of I-195, and features a 400-ft. (122 m) center span utilizing a tied-arch design. The bridge’s design is unique in that it uses three network arches rather than two, in order to support its large width totaling almost 170 ft. (51.3 m). It is the widest network arch bridge in the world.

Literally Building History

Steel fabrication of this centerpiece began in the fall of 2005 at a facility in Connecticut. All welding and painting took place indoors, and fabrication continued uninterrupted through the winter. RIDOT also chose to metalize the steel pieces for the bridge, an investment that will provide many years of service before repainting is needed.

The following spring the completed parts of the bridge were transported by truck to the Davisville Pier at the Quonset Business Park. In just a few months, the bridge was substantially complete and ready for the complex process of moving it to Providence.

At a cost of $3 million, Mammoet orchestrated a series of events that, once in motion, resulted in the bridge being moved in only a week’s time.

Before the bridge could be moved, however, it needed to be raised to a height of approximately 30 ft. (9.1 m). This allowed the bridge to be at a height taller than its piers when it arrived in Providence so it could be easily set in place.

Mammoet accomplished the jacking of the bridge by using a series of strand jacks, each capable of lifting 600 tons (544 t). Once the bridge was raised, Self-Propelled Modular Transporters (SPMTs) were driven underneath. These large motorized dollies carried cribbing made of steel and cargo containers, upon which the bridge rested.

Four days later, the towers used to hold the strand jacks were disassembled and the bridge was ready to move. On Aug. 25, 2006, the bridge was carefully rolled to the edge of the pier where two 300-ft. (91.4 m) barges were waiting. The barges were connected by two 100-ft. (30.5 m) crane booms to help stabilize them and the decks of both barges were kept flush with the surface of the pier by means of ballast control.

The following day the bridge was literally driven off the pier and onto the barges. This was done very slowly, and ballast water was pumped into and out of the barges as needed to keep them level as the weight of the bridge was transferred from the pier to the barges. The entire loading process took less than a day, and the following morning the stage was set for the water transport.

According to RIDOT, weather conditions were ideal at dawn on Aug. 27, 2006, and seas were calm. The barges were able to make almost twice the speed predicted and the entire assembly, which looked like a massive catamaran, arrived two hours ahead of schedule. The bridge was secured for night in preparation for final placement the following morning when the tide was lowest.

On Aug. 28, 2006, the bridge was positioned above its piers. Workers for Mammoet and Cardi Corporation carefully guided the bridge to its precise location as ballast water was pumped into the barges. Workers then severed the connections between the bridge and the barges and let the falling tide do the rest. The entire operation only took a few hours and the barges and their SPMT/container assemblies were low enough to be removed.

During the summer of 2007, Cardi completed the pouring of a concrete deck. On Nov. 3, 2007, a portion of the bridge was opened to traffic. CEG