Memorial Bridge’s replacement will be built quickly, using cutting-edge technology, but residents are less than thrilled with the design.

Engineers learned a great deal from the tragic I-35 bridge collapse in Minneapolis in 2007. The steel truss bridge, which crossed the Mississippi River, collapsed due to the failure of a single undersized gusset plate.

Like that structure, Memorial Bridge is a steel truss bridge that spans the Piscataqua River from Portsmouth to Kittery, Maine. And, like its counterpart in Minneapolis, it closed due to deterioration of its gusset plates.

That’s why the design of Memorial Bridge’s replacement calls for the total elimination of gusset plates.

“This will be the first truss anywhere that I know of that has no gusset plates. The gusset plates have been completely removed,” said Ted Zoli, chief engineer of HNTB.

Instead, the new bridge will use spliced connections, which are much easier to inspect and maintain, and which can be replaced without jeopardizing the safety of the entire structure, Zoli said.

HNTB designed the Memorial Bridge replacement and, with help from Archer Western Contractors, plans to have it open by July 2013. Zoli offered a presentation about the new bridge at Portsmouth City Hall on Nov. 29, addressing a packed crowd of roughly 150 people. He outlined a number of technological innovations that will be used to construct the bridge quickly and efficiently while making it as safe as possible for motorists, pedestrians and cyclists.

But, in a comment session after the presentation, a number of residents expressed dissatisfaction with the design. Some said the structure does not look modern enough; others said it does not retain the character of the original bridge. And several complained of being left out of the design planning process.

“I’m underwhelmed by the public and community participation to date,” said Portsmouth resident Peter Somssich, who served on the stakeholder committee of the Maine-NH Connections Study. “We should not be rushed into picking a design hastily.”

Archer Western and HNTB constituted one of six design-build teams that bid on the Memorial Bridge replacement project. At $81.42 million, Archer Western’s price tag was slightly higher than its competitors. But it promised to get the job done about five months faster, taking a total of 565 construction days, according to N.H. Department of Transportation project manager Keith Cota.

“They’re telling us that they can produce a project that will basically replace this bridge faster and use the best technical approach to do it,” Cota said.

For every day the bridge is open prior to the target date of July 3, 2013, the team will get an extra $25,000. For every day it goes past the deadline, however, it will incur a $25,000 penalty.

The governor and Executive Council are expected to approve the Archer Western contract on Dec. 14. Demolition of the existing bridge will begin next month, with removal of the lift span taking place Jan. 30, causing a three-day closure to marine navigation. There will be a slightly longer five-day closure when the new lift span is floated in during the spring of 2013.

Stephen Delgrosso, of Archer Western, said the contractor would use as much local labor as possible.

The new bridge design features some striking aesthetic differences. All three truss spans are identical in height, and the profile is more linear and less curved than the existing bridge. Those qualities allow for much quicker steel fabrication, Zoli said.

“It does give you, really, a different aesthetic. There’s no question about it. But a lot of that aesthetic is based on embracing, really, some groundbreaking ideas in truss design,” Zoli said. “We’re taking advantage of some emerging technologies.”

The new truss is shallower, but its steel plates are thicker. Also, unlike now, the truss will be outside the sidewalk, which will prevent plowed snow filled with corrosive de-icing salts from piling up against the steel. The steel will also be sprayed with corrosion-resistant metal that is more durable than paint.

Another advantage of the new bridge is that the lift span will open and close about 25 percent faster than the current structure, Zoli said.

Cota said New Hampshire and Maine will take a number of measures to minimize the impact of the bridge closure, including enhanced detour signage. They plan to establish an advisory committee with representatives from both communities to discuss communication, marketing and promotional opportunities.

Throughout the construction period, a shuttle with capacity for 12 passengers and six bicycles will operate on an hourly basis from 5 a.m. to 1 a.m., seven days a week, with stops at Prescott Park in Portsmouth and at the intersection of Newmarch and Water streets in Kittery, near the John Paul Jones Memorial.

Some residents worry the shuttle capacity will be inadequate. As of 2008, about 900 pedestrians and cyclists crossed Memorial Bridge each day, and that number jumped closer to 1,500 after the bridge closed to motor vehicles in late July. Cota said the DOT would monitor the system and adjust as necessary.

The new bridge will have 11-foot vehicle lanes and five-foot shoulders for bicycle traffic. A Portsmouth Naval Shipyard employee who cycles to work each day questioned whether the bike lanes will be safe. Cota pointed out that many roadways in New Hampshire and Maine have four-foot bike lanes along streets with higher speed limits. He said the five-foot shoulder “meets and exceeds” safety criteria.

“It’s a massive improvement over what you currently have today, and we feel it will still be safe,” he said.

A more common concern among guests at the meeting involved the appearance of the new bridge. Kittery resident Susan Emery was “very disappointed” by the design, which she said “looks much too functional” and “plain.” Portsmouth resident Gerald Duffy agreed, saying he had hoped for a more contemporary design.

Zoli seemed taken aback by the remarks, saying he and other engineers had worried the design was too modern. He said the DOT’s request for proposals demanded the new bridge look similar to the existing structure.

Furthermore, Zoli said, there is only so much engineers can do to alter the appearance of a truss bridge with a lift span. “Moveable bridges are the most constrained type of systems,” he said.

Others, including Peter Somssich, accused the DOT of cutting residents out of the conversation about the bridge design. Kittery resident Steve Workman, another member of the stakeholder committee, said DOT officials had promised to include them in such discussions but never followed through.

“It does feel like our legs got cut out from under us at some point. And a lot of us invested volunteer time to do this,” Workman said.

Cota said the DOT is still seeking feedback about some design elements, but any major changes would push the project behind schedule and over budget.

Portsmouth architect Lisa DeStefano suggested draping a series of cables from the lift towers that would serve no functional purpose but would “harken back to the arches and sweeps we see in the existing bridge.”

Several residents stressed the importance of a lighting system that will make the bridge attractive at night. Tom Emerson, a member of the Kittery Planning Board, suggested using a different color, like the Golden Gate Bridge, or implementing public artwork, like the “Fremont Troll” in Seattle. Susan Turner, of Portsmouth, requested suicide barriers to prevent people from jumping off the bridge.

Even after the new bridge opens, there’s still work to be done on the connections between Portsmouth and Kittery. Cota said the Sarah Mildred Long Bridge will soon replace Memorial Bridge atop the state’s red list of bridges in need of repair. The two states still must decide whether they will replace or rehabilitate the Sarah Long.