Interstate H-1 Waimalu Viaduct Widening

Location: Oahu, Hawaii
Client Name: State of Hawaii, Department of Transportation, Highways Division
Date Completed: 2001
Construction Cost: $60,000,000
Disciplines Applied: Civil Engineering, Surveying & MappingPlanning & Permitting (for EA, planning for relocation of 12 families, NPDES permitting, public participation program)

Project Description:

RMTC was contracted to prepare designs, plans, specifications and cost estimate for the construction of this project which featured widening of the Interstate Route H-1 (H-1) westbound by approximately 30 feet between the Kaonohi Street overcrossing and the Pearl City Off-Ramp. The purpose of the widening was to meet current interstate standards and enhance traffic flow. The existing road section consisted of five 11-foot wide lanes, a 4-foot wide median shoulder and a 10-foot wide right shoulder. Now completed, the new road section consists of six 12-foot lanes, a 10-foot median shoulder and a 12-foot right shoulder.

Modifications were made to the following:

  • Waimalu Viaduct structure;
  • improvements to meet current State and Federal seismic standards;
  • the Austin-Bishop Separation bridge structure (Kaahumanu Street overcrossing);
  • installation of noise barrier walls along portions of the project limits;
  • H-1 roadside and cross drainage systems;
  • H-1 lighting and power system;
  • restoration and enhancement of landscaping and modification of the H-1 irrigation system;
  • other utilities along and/or crossing H-1 to accommodate the improvements;
  • beautification and safety improvements to remnant State parcels below Waimalu Viaduct, including landscaping, irrigation and fencing;
  • permanent roadway and utility modifications to accommodate the improvements along Moanalua Road, Kaahele Street, Pono Street, Ponokaulike Street, Ponokaulike Place, Ponohana Loop and Ponohana Place;
  • adjustments to Waimalu BWS pump station, Waimalu Stream overbanks, Newtown Driving Range and other lots adjacent to the right-of-way; and
  • traffic safety features within the project limits.