When it first opened to two-way traffic on Feb. 27, 1943, what is now the northbound span of the Gold Star Memorial Bridge cost automobile drivers a 15-cent toll for crossing the Thames River.

Originally known as the Groton-New London Bridge, the Gold Star predates Interstate 95 by two decades.

State transportation officials now estimate it will cost about 30 times the original $6 million construction cost — between $150 million and $200 million — for the rehabilitation needed to improve the “poor condition” rating the bridge received after its last inspection in 2013. By federal standards, it is structurally deficient.

Gov. Dannel P. Malloy, who presented a 30-year transportation plan in his budget last week, stood underneath the bridge in January “to highlight the importance of long-term planning and investment in all modes of Connecticut’s transportation infrastructure.”

“We can’t afford to wait any longer to fix our aging bridges and infrastructure,” he said.

State Department of Transportation spokesman Kevin Nursick said the poor rating is not an indication that the bridge is unsafe, only that it is in need of maintenance.

“The inspection process identifies areas of concern years in advance of any major problems,” Nursick said. “There are hundreds of millions of vehicle trips on bridges across the country. They are immensely overbuilt for their job. The Gold Star Bridge is a long way from being an unsafe bridge.”

He said the bridge has reached the point, however, that plans are underway for major rehabilitation work. Comparing it to the aging of the human body, Nursick said the work is “like hip replacement or knee work.”

Engineers are refining an evaluation of rehabilitation options to define the scope of the work. Options could include repairs to last either 25 years or 50 years, along with how much it would cost to replace the bridge.

In his 30-year transportation proposal released this week, Malloy included $900 million for replacement of the northbound bridge. A spokesman for Malloy said the upcoming repairs and rehabilitation of the bridge are part of the five-year plan for the short-term. The replacement of the northbound bridge is part of the 30-year plan, which does not yet have funding identified.

Nursick said the upcoming rehabilitation project will be paid for through the DOT’s capital improvement fund. A final renovation plan should be completed by the beginning of 2017 with a project ready to start shortly thereafter, he said.

When construction was completed on the steel arch deck truss bridge more than 70 years ago, it was one of the longest, highest and most costly bridges in New England. Its twin was completed in 1973 and now carries southbound traffic. At more than one mile, or 5,925 feet long, the Gold Star is still the longest bridge in Connecticut.

As are all bridges in the state, the Gold Star is inspected at least once every two years, Nursick said. Gov. M. Jodi Rell announced the two-year inspection schedule in 2007 following the collapse of a deck truss bridge in Minneapolis that killed 13 people. Previously, Connecticut was inspecting some bridges on a four-year schedule as a cost-saving measure.

Inspections of both spans of the Gold Star Bridge are painstaking tasks that take a team of more than a dozen inspectors about 2,000 hours to complete. The inspection costs about $500,000, according to the state DOT.

The bridge is inspected with specialized equipment such as 50- and 75-foot snoopers, flatbed tractor trailers with hydraulic arms to maneuver a manned bucket over and under the bridge from the top of the span. Lane closures require state troopers and crash trucks, local police closing roads below the bridge and even some climbers navigating the truss spans and tops of piers.

The scope of work for the next major project will be guided by the details presented in the DOT’s inspection report, a portion of which was obtained by The Day. The 23-page section of the report, called the BRI-18, rates each individual component of the bridge and has extensive notes by inspectors about deficiencies.

In the latest inspection, in 2013, the northbound bridge received an unflattering overall grade of 4, or poor, on a 0-to-9 scale for evaluating the condition of the bridge’s three main components: deck, superstructure and substructure.

In the evaluation of the bridge’s parapets or side walls, inspectors noted small cracks and 92 hollow-sounding concrete spots. It received a score of 4. The aluminum railings, on the other hand, rated an 8, in good condition with no notable deficiencies.

Both the superstructure and deck received a poor grade while the substructure received a grade of 5, or fair.

The superstructure, between the deck and the concrete piers that make up the substructure, received poor grades for things like the bearing devices, floor beams and trusses. The substructure, consisting of reinforced concrete abutments and piers with steel columns, received a 5.

The bridge has been the focus of numerous rehabilitation projects through the years, most recently repairs to a frozen rocker bearing on the structure, Nursick said.

“It’s what the superstructure sits on and allows the bridge to rock forward and back when the bridge contracts,” Nursick said. “When the bearing freezes from corrosion it can’t expand and contract properly.”

That project, which started in February 2014, finished in November.

There was also a major superstructure project in the 1970s and painting in the 1990s. Joint work and pavement preservation is slated to start in the spring.

Another inspection of the northbound side of the bridge is slated to start later this year.

While the northbound side needs the majority of the work, the southbound span and a two-lane off ramp in New London are also due for work scheduled to start in 2017 at a cost of more than $20 million. The work includes replacement of expansion joints on the deck of the structure, elements of the bridge that expands and contract, and have a limited lifespan.

There are also structural repairs, spot painting, replacement of asphalt on the deck, concrete substructure repairs, drainage improvements and replacement of overhead signs to be done.

The southbound side of the Gold Star currently holds an overall rating of 5, or fair condition.

g.smith@theday.com

Twitter:@SmittyDay

Hearing on Gold Star Bridge project

The state Department of Transportation will hold a public informational hearing at 7 p.m.Thursday in City Council Chambers in New London to explain the rehabilitation project scheduled to begin in 2017 on the southbound side of the Gold Star Memorial Bridge.