INCA prepared the plans, specifications, and estimate for the construction of a flashing crosswalk system on NE 124th Street near the intersection of 105th Avenue NE.  This system includes in-pavement flashing lights, illumination, power service, signage, and sidewalk revisions to meet ADA requirements.

The project was part of an on-call agreement with King County. INCA Engineers provided King County Department of Transportation with professional engineering services on a work order basis for various transportation projects, which included ITS strategic planning, preliminary and final design, communications analysis and design traffic analysis, traffic forecasting and modeling, and signal and illumination design.

The John Day Navigation Lock utilized a steel navigation lock lift gate which is 90 feet wide by 113 feet high, with a maximum heat of 125 feet. The gate is constructed of a series of horizontal bowstring trusses with a skin plate on the upstream side, and the trusses are spaced so that each truss receives approximately the same load. There has been many problems with welds and members cracking since 1963, when the lift gate was put into service. The gate was originally not accepted as constructed and required significant weld testing and repairs.

Tetra Tech INCA prepared an investigative report for the evaluation of cracking in the downstream John Day Navigation Lock lift gate. Cracks were located in the tension ties at the vee joint connections to the arch ribs and at the welded intersection of bracing members and diaphragm edge stiffeners. INCA evaluated the condition of the gate and provided recommendations for immediate and long-term repairs.

INCA reviewed historical data (hydrostatic and hydrodynamic as well as lifting forces), compared Ice Harbor and John Day Dams design and cracking problem similarities, and developed a reliability assessment to determine the existing gate’s remaining life. INCA provided an assessment of the existing gate condition and provided recommendations for any required emergency repairs. A 3D finite element model was developed to assess the level of stress in the members. INCA developed cost estimates for maintaining the existing gate, modifying the existing gate, and constructing a new gate.

Tetra Tech INCA prepared plans, specifications, and estimates for the construction of right-turn lanes and signal modifications for intersections within the City of Kirkland. The design included the addition of right-turn lanes, intersection improvements, stormwater treatment facilities, traffic signal modifications, curb, gutter and sidewalks, striping, and retaining walls. INCA conducted subsurface utility explorations at each signal pole foundation location to identify potential utility impacts prior to construction.

Tetra Tech INCA provided preliminary and final design for the Sitka Dock. INCA developed alternatives for the shore connections and mooring system; analyzed loads, tidal fluctuations, and wind loads; evaluated and developed alternatives for pontoon reinforcement; and provided siting of the pontoon. Special features included the design of ramp connections using a specially fabricated set of elastomeric and steel bearings for kinetic energy absorption in the event of docking collisions.

This design was named an “Outstanding Example of Excellence in Concrete Construction” by the Washington Aggregates and Concrete Association.

Tetra Tech INCA provided design for improvements to Kamber Road, between Richards Road and 137th Avenue SE. Improvements included complete design for sections of concrete sidewalk and bicycle lanes along the roadway; full width overlay with reconstruction in selected areas; design of a new bridge at East Creek; and waterline and sanitary sewer repair and replacement; and signal interconnect along the road.

The poor geotechnical conditions made relocation of utilities very difficult, potentially leading to settling of the roadway. INCA identified options that reduced the need to relocate utilities. This analysis resulted in a $500,000 reduction of overall project construction cost and shortened the construction schedule by two months.

Kamber Road was selected as APWA’s “Public Works Project of the Year” 2007.