Highways

MAKAHA BRIDGE REPLACEMENT

Farrington Highway, Replacement of Makaha Bridge No. 3 & No. 3A
District of Waianae, Island of Oahu, State of Hawaii
Project No. BR-093-1(20)

Project information
The State of Hawaii Department of Transportation (HDOT), Highways Division, is proposing to replace Bridge No. 3 and No. 3A, two aging wood bridges with prefabricated steel bridges and an epoxy coated deck. This project is located in Makaha in the Waianae District on the island of Oahu. Bridge No. 3 and No. 3A are located along Farrington Highway near Kili Drive at mile marker 14.02 (No. 3) and mile marker 14.096 (No. 3A).

Project purpose and need

The existing bridges were built in 1937 and is currently ranked as the top two priority bridges in need of an upgrade. The purpose of the project is to improve its structural integrity, hydraulic openings, and stream channel improvements.

The bridges will ensure that residents west of the bridge sites will have continued safe access to the highways. The structures will include 11 foot travel lanes and 7.5 foot shoulders, improvements along two drainageways, relocation of bus facilities, guardrail upgrades, replacement of existing driveways, relocation of water and electrical utilities, and signage upgrades.

The placement of the bridges will ensure that the structures will not preclude future realignment of Farrington Highway and will consider long term effects of climate change and sea level rise. Stream openings and other weather-resistant features of the Makaha Bridge No. 3 and 3A replacements will remain within the 100-year storm level predictions.

Project Environment Considerations
The proposed project anticipates most work to occur without lane closures. When closures are needed, public notice will be advertised, and variable message boards will be installed. Construction will work to reduce rights of way and commit to minimizing impacts on the public, including implementing the following measures.

• 2 Lane access will be maintained for most of construction period.
• Off peak intermittent single lane closures will be implemented when necessary.
• Bridge demolition and launching will require 2 full weekend shutdowns over 2-3 days with a detour in place.
• Contractor will work with Waianae High School to determine short and midterm opportunities.
• Contractor will coordinate with emergency management to ensure services are available during shutdown.

Proposed Redesign

The proposed redesign of Makaha Bridge #3 and #3A will use prefabricated steel rather than the originally planned concrete structure. The use of pre-fabricated steel elements is expected to reduce the cost of replacements for the existing bridges by 10-20 percent. The new plan has reduced construction costs by eliminating the need of a temporary bypass road, temporary bridge and culverts, center pier at bridge #3, and construction parcel on the East Makai side of Bridge 3.

Project Schedule

The Makaha Bridge Replacement project is anticipated to begin by fall 2021. The redesign of construction has reduced the working schedule from 15 months to 9 months, with an anticipated completion date of Summer 2022, pending approvals and weather conditions.