The relocation of an underground gas main under I-405 was required as part of a Washington State DOT (WSDOT) road-widening plan for 116th Street, a major east-west arterial in Kirkland, Wash.
Pilchuck Contractors, a major natural gas installation and repair company based in Kirkland, which is affiliated with Puget Sound Energy, did the work. Project Manager Tom Ling was responsible for coordinating all of the various aspects of the work.
There were a few challenges related to this job: There were two large traffic generators in the vicinity, a large hospital to the east of I-405 and a large residential area on the west side of I-405; the proposed rerouting of major traffic flow around a natural gas pipeline relocation had to be shown clearly; traffic-control revisions from WSDOT traffic engineers and other involved parties had to be incorporated clearly; and businesses and emergency services had to be kept informed of traffic-control decisions and information needed to be distributed to all involved parties.
Nearby businesses were kept informed, and it was determined that it would be in the best interest of all to perform the work at night. All business entrances would be kept open by using nonskid steel plates over excavations.
Rob Inglis, a traffic-control designer working in Seattle, used TrafficGraphics software to create all of the traffic-control drawings over the course of the project. The software is available from Professional Traffic Graphics Inc.
The initial traffic-control concept was approved by Pilchuck’s project manager and relayed to Inglis. For this project, Inglis chose to start with a color aerial photo of the area, then the lanes and traffic lines were traced in yellow to show more contrast against the gray-green of the photograph. The color signs and symbols were imported and laid out according to MUTCD standards. Inglis then spotlighted various details of the larger drawing using the TrafficGraphics advanced functions in order to show close-up views of individual situations.
Inglis worked closely with the WSDOT engineers, and their revisions were easily incorporated into the existing drawing. It was determined that a police officer would be needed at the intersection of 116th Street and the east I-405 off-ramp and that no left turns would be allowed onto the west I-405 on-ramp. A detour was proposed to allow traffic access to southbound I-405. These changes were added quickly and smoothly. The drawings were converted to PDF (Adobe Acrobat) format for ease of e-mail distribution. The final drawings were approved by WSDOT and permits were issued, and Pilchuck was able to get the construction, which lasted about 21?2 weeks, done on schedule.
