A nearly 100-year-old bridge built over the Ala Wai Canal will undergo significant repairs over the coming year, the city says.

Starting Monday, a $2.6 million project to repair the Kala­kaua Avenue Bridge and roadway will occur Mondays through Fridays, 8:30 a.m. to 3:30 p.m.

The work is expected to take about a year to complete, the city says.

Built in 1929, the bridge — part of a heavily traveled thoroughfare leading into and out of Waikiki — has seen its overall condition degrade over time, the city says.

“The condition of the bridge superstructure is rated ‘poor,’” Cindy Cromwell, city Department of Design and Construction spokesperson, told the Honolulu Star-Advertiser via email. “The rehabilitation work is necessary to restore the structural integrity of the bridge and thus ensure public safety.”

Kaikor Construction Group Inc. was awarded the contract for this repair project, she added.

The work includes repairing cracks, spalling and delamination on the existing bridge structure; filling cavities at the downstream wing wall and sidewalk areas; and replacing affected concrete sidewalk, she said.

“During construction, the traffic on the bridge will remain open with one lane on the bridge blocked off at a time for sidewalk and railing repair work,” Cromwell said.

According to the city, during the work, occasional traffic and pedestrian delays might occur. Single-lane closures along Kala­kaua Avenue and Ala Wai Boulevard are needed for the contractor to perform its work.

Sidewalk repairs along both sides of the bridge will require 24-hour closure of one sidewalk at a time for about two weeks. Pedestrians can use the sidewalk on one side of the bridge when the opposite side is closed. Motorists and pedestrians are advised to use alternate routes, the city says.

Cromwell said the last time the Kalakaua Avenue Bridge was worked on was over 20 years ago. “There was a mauka sidewalk improvement project in 1999,” she added.

In 2017, the last time an annual daily traffic count occurred, about 42,420 vehicles crossed the bridge in a year’s time. Cromwell said the current traffic count for the bridge may be higher, though no traffic numbers were immediately available.

Besides the city, this project has not received additional funding from any outside agency, including from the federal government.

“No federal funds have been or are planned to be used on this project,” Cromwell said.

In past years both Honolulu and the state have received poor marks for the condition of their bridges, roads and other man-made infrastructure.

In particular, the American Society of Civil Engineers — founded in 1852 and representing 150,000 civil engineers worldwide — previously rated Hawaii’s bridges as part of its so-called “Report Card” for America’s infrastructure.

In 2019 the organization gave the state of Hawaii a D+ for its overall infrastructure, while it graded the state as well as the City and County of Honolulu at a C+ level for its bridges.

Under its grading system, an “A” means a structure, like a bridge, is exceptional and fit for the future; a “C” grade deems it mediocre and that it requires attention; and a “D” means it’s in poor shape and at risk, the group says.

To determine those grades, ASCE’s report evaluated several categories including capacity, condition, funding, future need, operation and maintenance, public safety, resilience and innovation with regard to infrastructure.

“Hawaii’s 1,135 bridges have an average age of 60 years. Of these bridges, 6.9% are structurally deficient,” the 2019 ASCE report states. “While the percentage of bridges rated to be in good condition has risen over the past several years due to rehabilitation efforts, the number of structurally deficient bridges has also increased during the same time period. In addition, due to the state’s isolated location, marine environment and various natural hazards, bridge construction costs are the highest in the nation.

“Therefore, current efforts by state and county agencies are focused on preserving the existing bridge inventory and maintaining safety rather than upgrading bridge capacity or resilience to meet future needs,” the report states. “To this end, there are 44 state bridges and up to 34 City and County of Honolulu bridges slated for repair in the next four to six years.”