KAILUA-KONA — Efforts to replace an 86-year-old bridge in Waimea are gearing up again.
The state Department of Transportation plans to advertise later this week a notice of interest to procure a design consultant to prepare new documents, design plans, project specifications and cost estimates for replacing the Waiaka Stream Bridge, said DOT spokeswoman Shelly Kunishige.
Meanwhile, the department said it will revise the weight limit for the bridge after the agency announced a lower limit earlier this month following a reassessment of how it calculates weight restrictions to account for heavy truck loads.
An effort to replace the decades-old bridge, located close to the intersection of Kohala Mountain and Kawaihae roads in Waimea, has been on and off for years.
In 2011, the state released a draft environmental assessment to replace the 38-foot-long, 26-foot-wide bridge with one that’s 80 feet long and 53 feet wide, featuring a shoulder/bike lane and raised sidewalk with railings. It was estimated that the project would cost about $8 million to $14 million, not including land acquisition costs.
At that time, an inspection of Waiaka Stream Bridge turned up a sufficiency rating of 26 out 100, where 100 means a sufficient bridge that meets current engineering design standards. That score meant the bridge was structurally deficient and in need of repair or assessment. The environmental assessment, however, said that didn’t mean the bridge was unsafe.
A DOT webpage that identifies the status of various infrastructure projects marked the bridge as being in “good” condition.
Kunishige said the website reflects only the physical bridge condition, while the sufficiency rating takes into account multiple criteria. The “26” rating was because of the bridge’s deck geometry, approach alignment and design capacity, she added, “but the bridge supports and deck themselves are sound.”
In 2015, DOT pulled the final environmental assessment and finding of no significant impact because of “new circumstances and information that require additional studies,” according to a letter from the director released at the time.
In 2017, lawmakers approved a budget with $6 million for planning and land acquisition; it didn’t include money for actual construction. That sum included $4.8 million in federal funds, with the remaining $1.2 million coming from highway revenue bond funds, Kunishige said.
In the meantime, the department’s Hawaii District office is looking into potential short-term improvements to the bridge, such as widening the road on the approach, and will have the results of that investigation in May.
Earlier this month, the department announced a reduction in the weight restriction for the Waiaka bridge and several others throughout the state. That included lowering the limit for Waiaka Stream Bridge to 15 tons. Kunishige said a limit for the bridge was previously not posted. The limit for unposted bridges, she said, is 40 tons.
Kunishige said previous guidance was based on lower vehicle loads and wasn’t the result of any structural changes to the bridges.
“As the federal guidance is updated and adjusted to account for newer, heavier vehicles, our calculations are being updated and adjusted as well,” she said.
In a letter to Hawaii Island officials and the manager of a local trucking company, DOT Highways Division Deputy Director Ed Sniffen said staff reanalyzed the Waiaka bridge to consider average daily truck traffic and will revise the weight limit to 18 tons.
The new limits won’t affect passenger vehicles, the agency said, which typically weigh about 2 tons. However, other vehicles, such as emergency vehicles, buses and tractor-trailers, might be affected by the change.
Kunishige said bridge design staff coordinated with the state Department of Education and various county agencies about the posted weight restrictions and pre-cleared many school buses and transit service vehicles. Vehicles that aren’t cleared, she said, are eligible for annual permits to travel over the bridge.
While the department can’t offer annual permits to truck operators, whose loads change trip to trip, Kunishige said operators should contact the district office if they want to pre-clear their maximum load.
Email Cameron Miculka at cmiculka@westhawaiitoday.com.