City Zeroes In On Bridge Conditions

The Grand Avenue bridge over the Quinnipiac River has rusty joints. Located in the seams between the segments of the bridge, the rust has begun to expand. This is the source of a widely-known bump on that bridge — one that City Engineer Giovanni Zinn intends to fix.

Zinn and Chief Structural Engineer Zachary Shapiro have compiled a comprehensive report on the conditions of a total of 167 bridges in New Haven, drawing information from biennial inspections of the bridges conducted by the Connecticut Department of Transportation as well as the city’s own check-ups. This year’s report, unlike in past years, evaluates bridges maintained by the state of Connecticut and Amtrak in addition to 60 city-owned bridges.

In the report, Zinn and Shapiro concluded that two city-owned bridges, two state-owned bridges, and one Amtrak-owned bridge in New Haven are in poor condition. The pair outlined repairs for the city- and state-owned structures in need of work.

During inspections, each bridge gets a set of condition ratings, which evaluate several components of the bridge including both the surface road and the substructure.

“You’re looking for signs of wear, signs of contact — any type of sign of distress,” Shapiro, who is certified in bridge inspection, explained during a tour of some the bridges earlier that day. Inspectors take photographs as they examine the bridges, he added. ​“You look for corroded parts of metal. You look for cracks.”

Some of the bridges detailed in the report might easily be mistaken for regular roads. Take, for instance, a stretch of Crown Street between Temple and Church, marked on each end by two bands of darker concrete.

“I guarantee there’s probably 20 people in New Haven who know it’s a bridge,” Zinn said.

Underground, beneath that segment of the street, is the Church Street Tunnel.

That Crown Street bridge received inspection scores of 7s and 8s across various categories out of 9. Those scores mean that the bridge is ​“in pretty good shape,” Zinn said. It’s rare for a bridge to receive a score of 9, he added.

Bridges with scores of 4 and below are considered to be in ​“poor condition.” This classification has traditionally been the threshold for a bridge to qualify for state and federal funding for repairs. Lately, Zinn said, Connecticut has started to fund smaller-scale preservation projects designed to prevent minor signs of distress from worsening.

Zinn focused on that bridge and several others at a presentation of the new report to the Board of Alders City Services and Environmental Policy Committee meeting held last week at City Hall.

At the committee meeting, Zinn explained to the alders that bridges receiving a score of 3 will begin to be inspected at a more frequent rate than the standard two-year intervals.

“Now you’re making me nervous,” Cedar Hill Alder Anna Festa said. “’Cause I would want that fixed right away.”

“We’re on top of it,” Zinn reassured the committee.

“I know you are, but I worry that the state isn’t,” Festa responded.

Zinn affirmed that no bridge in the city has gotten to the point of a more frequent inspection schedule because of poor conditions.

He flipped through slides of photos as he delved into a few particular bridges in need of minor and major repairs.

The bump on the Grand Avenue bridge is hardly the only defect that contributed to its ​“poor condition” status. In a $25 million rehabilitation effort, Zinn wants to replace the bridge’s approach spans, the parts of the bridge nearest to land, which are well over a century old. He also wants to replace the system of wheels, gears, and drum girder that opens and closes the bridge. Engineers’ main concern is that the bridge might get stuck in an open position if conditions worsen beyond a certain point, Zinn said.

In addition, engineers plan to adjust the bridge in anticipation of the rising sea levels that come with climate change. He recalled that when Hurricane Sandy hit New Haven, water levels rose up to the bridge’s drum girder, several feet above the river’s current height. His team will elevate the bridge’s electrical equipment to protect it from potential water damage.

Bridges’ materials often expand in the heat, and engineers account for this with ​“joints” between segments that allow for a measure of flexibility in the bridge’s expansion. On hot summer days, Zinn said, the Grand Avenue bridge has expanded so much that the Fire Department needed to hose it down with cold water.

Zinn attributed the bridge’s dramatic expansion partly to its heat-absorbent black paint. The bridge will be repainted, he said, and the color will be decided by a ranked choice voting system. Some of the colors on the ballot include a red mimicking the Ferry Street bridge, a shade of green popular in Oregon that Zinn likened to a ​“rustic copper,” and a historically-minded ​“yellowish-white.” Black will also be an option for residents who like the bridge the way it is.

Zinn anticipates that construction on the bridge will begin in 2020 and last between one and two years.

The other city-owned bridge deemed to be in poor condition is the Humphrey Street bridge over the Mill River.

While the top half of the bridge received scores of 6 and 7, the bridge’s sub-structure received a four. The stones on the central piers holding up the bridge have lost some mortar and are starting to shift. Some scour — a process by which the riverbank around the bridge erodes, often during storms — has also occurred. Scour can expose parts of the bridge to damage and decay.

Repairs to this bridge, set to begin in Spring of 2021, will include adding large stones, called ​“rip rap,” by the shore and the foot of the bridge so as to reshape and stabilize the riverbank.

The city will add a new waterproofing membrane to the road over the bridge, while possibly also installing pedestrian lighting along the sidewalks.

Other city-owned spans that Zinn and Shapiro mentioned include the bridge on Edgewood Avenue over West River, the bridge on Orange Street over the Mill River, and the bridge on Ferry Street over the Quinnipiac river. Zinn noted minor repairs that might benefit these bridges, saying that his department will weigh the costs and benefits of making those fixes now or waiting a decade or so to make more substantial repairs.

As part of a new practice, Zinn and Shapiro also presented on two state-owned bridges in poor condition: the bridge on South End Road over Morris Creek, which the state plans to replace beginning in Spring of 2022; and the bridge on Ferry Street over the railroad, which is due for a thorough repair. Zinn said he is working with the state to mitigate potential traffic problems that the Ferry Street bridge’s construction could pose.

View the full Bridge Condition Report here.