The state Department of Transportation announced Thursday that crews have started construction on a long-awaited project to rehabilitate Roosevelt Bridge in Central Oahu.

The $14.9 million project, 80 percent of which is funded through federal dollars and 20 percent from state money, will improve the bridge’s safety and its structural capacity, as well as widen it to provide for a 7-foot shoulder lane on both sides of the two-lane stretch. Work will also include bridge railing replacements, seismic retrofits and concrete crack repair. The contract was awarded to Hawaiian Dredging Construction Co.

Lane closures in the area are expected during six weekends between May and December. The first closure of the bridge is scheduled for 9 p.m. May 5 to 5 a.m. May 8. Traffic will be detoured to the H-2 freeway.

The Roosevelt Bridge is at mile point 14.4 on Kamehameha Highway near Kipapa Gulch between Ka Uka Boulevard and Lanikuhana Avenue. It is about 484 feet long and 34 feet wide.

The bridge, which was built in 1933, does not meet current design standards for roadway width and load capacity, and can accommodate only 16-ton loads. After the project’s completion, which is slated for January, the bridge will be able to hold 35-ton loads, DOT said. The wider shoulder lanes would also be used for pedestrians and bicyclists.

At a blessing ceremony Thursday, with state and federal officials in attendance, Ed Sniffen, who heads DOT’s Highways Division, said the bridge, described as a major thoroughfare for Central Oahu, is safe but needs to be improved because it was built to design standards in the 1930s. He said the project has “been on the books for many years.”

“Our focus is on the preservation (of existing roads) and our safety first,” Sniffen said. “We must get this done as soon as possible.”

DOT officials are also in the planning stages of another project to add more lanes in the area. Sniffen said the two options, which would cost about $100 million to $200 million each, would be to realign the bridge or to build another bridge next to the existing one. Sniffen said because the state is already spending money to improve the bridge, the more feasible option would be to build another one next to it. But he said there is no time frame to get that project started.

State Sen. Michelle Kidani said residents have not expressed safety concerns about the bridge, but have pushed for more lanes in the area. Kidani (D, Mililani-Waikele-Kunia) said the project has been discussed for many years and that “it will much improve the safety (of the bridge).”