Half of state's bridges fall short of standards
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By Jan TenBruggencate
Advertiser Staff Writer
By Jan TenBruggencate
The condition of state bridges has shown little improvement over the last several years, with nearly half failing to meet federal standards in several surveys.
Although there has been a little progress year-over-year, the state and the counties are not making significant strides. Fully half of the state's bridges were substandard by federal measures in 2001, and 46 percent still were in 2006.
Most of the substandard bridges in 2006 are the same ones that were poorly rated in 2001.
State highway officials say their funding is far short of what's needed to significantly change that.
Hawai'i has the third-worst record in the country with 513 of its 1,110 bridges rated substandard. Only Rhode Island and Massachusetts have a higher proportion of substandard bridges, and the national average is 25.8 percent.
One reason for the poor ranking is that Hawai'i has many old bridges that don't meet current federal highway standards, but are in no danger of failing.
"They are not a problem from a structural point of view, but they will never meet standards," said Ian Robertson, a professor of structural engineering at the University of Hawai'i.
Crawl under any old bridge and you're likely to find issues. Cracked concrete. Flaking rust. Foundations crumbling. Streams eroding the soil and rock under bridge supports.
The big issue in fixing that is the cost. State bridges alone need $2 billion to bring them all up to standard, state Transportation Department spokesman Scott Ishikawa said.
The federal government provides about $20 million a year — just 1 percent of the need. Federal money generally covers 80 percent of bridge work and state funds cover the remainder, but Ishikawa said the state is able to rehabilitate or replace only two to five bridges a year.
With 275 deficient or obsolete bridges out of 758 bridges under the Transportation Department's control, that means it fixes between 1 and 2 percent of its bridges annually.
"Whatever our budget allows, we try to build as many bridges as we can, but nationally, the federal transportation budget is shrinking year after year," he said.
'I DON'T SEE A HUGE ISSUE'
Robertson said that given the budget issues, the state is doing a good job by conventional standards.
"I don't see a huge issue here any more than any other state, but we will always be low in the national rankings because of our historical bridges," he said.
State and county officials insist they inspect regularly, make repairs where needed, and when they can't bring a bridge up to its original standard, they reduce the allowed load.
"Those structures that cannot safely carry current vehicle legal loads are posted with weight limits," he said.
Both state and county officials say that while bridges may be ranked as substandard, that does not mean they are in danger of failure, or even that they are necessarily unsafe.
"We inspect them, and if we see a problem, we correct it. If something is unsafe, we'll address it right away," said Eugene Lee, director of the City and County of Honolulu's Department of Design and Construction.
The city has 418 bridges that it keeps track of. Those under federal oversight — about half of them — are inspected every two years. The rest, which tend to be smaller bridges that don't carry much traffic, are inspected every four or five years, Lee said.
Of the 1,110 bridges listed by the Federal Highway Administration for Hawai'i in 2006, 513 were considered "structurally deficient" or "functionally obsolete." Five years earlier, there were 1,071 bridges listed, and 537 were deficient or obsolete.
The highway administration defines bridges as structurally deficient if engineers have been required to close them, or will need to close them without immediate work or if their use has been limited to light vehicles.
Functionally obsolete bridges have issues related to how much they can carry, or the conditions of the road approaching the bridge that no longer meet the criteria for the system of which the bridge is a part.
That generally means standards have changed or highway speeds have been increased and the bridge no longer meets current requirements.
"A perfectly good bridge that was fine yesterday can be obsolete today because the standards changed," Lee said.
Many of the state's multitude of concrete bridges that span small streams, while they may date back 70 or 80 years, are sturdy and should last many years more.
In some cases, communities demand that historic bridges be preserved, sometimes due to their historic character, but sometimes also because the aged, often one-lane bridges on some rural roads — like ones on Maui's Hana Highway and Kaua'i's North Shore — discourage speeding and reduce traffic.
The steel trusses of the Hanalei Bridge, crossing Hanalei River, were so severely corroded that chunks of rust would sometimes fall and hit cars, but the community insisted that the look and feel of the 1912 wood-decked bridge be preserved. Ultimately, the state Department of Transportation in 2003 built an entirely new steel truss bridge on the site, to the same original one-lane design.
"The Hanalei Bridge is going to remain on the (obsolete) list, because it's a one-lane bridge," Ishikawa said.
A few miles down the road, the state kept maintaining a 48-year-old wood and steel bridge over the Wainiha River. Then one day in 2004, it developed a significant sag.
Authorities said they suspected that it failed under a construction vehicle much heavier than the bridge's rated load. The state built a galvanized steel truss bridge that sits atop the old Wainiha No. 2 bridge, which remains in place. The truss bridge is considered temporary.
On O'ahu, the city recently rehabilitated Hale'iwa's classic 1921 Anahulu Stream Bridge, also known as the Rainbow Bridge, rather than replacing it with a bridge of modern design.
Aged bridges that have archaic designs are one reason the state has such a poor showing on the list of substandard bridges, Ishikawa said.
"Some of the bridges on the road to Hana, we can fix them up, but as long as they stay one-lane, they remain on the list as obsolete bridges," he said.
Federal statistics seem to indicate that while Hawai'i has a lot of substandard bridges compared to the national average, that's partly because so many of them are obsolete bridges.
If only those bridges classified structurally deficient are counted, Hawai'i actually ranks near the national average — with 14 percent of bridges deficient compared to 12.4 percent nationwide.
"This state has done a good job of replacing and retrofitting bridges as needed," said Robertson, the UH engineering professor.
Both the state and the counties have lists for the repair of bridges. The state's major bridge construction list through 2021 calls for rehabilitation, widening or replacement of 11 Kaua'i bridges, two on Moloka'i, two on Maui, seven on the Big Island and 27 on O'ahu.
Government officials can occasionally improve the bridge situation without dipping into their own pockets.
State deputy director for civil defense Ed Teixeira said that Federal Emergency Management Funding was used to make earthquake damage retrofits on a number of Hamakua Coast bridges that were deemed critical for emergency transportation.
None of those bridges suffered significant damage in the Oct. 15 Big Island earthquakes, although unimproved bridges did, Teixeira said.
Reach Jan TenBruggencate at email@example.com.