The Link Light Rail Capitol Hill Station (CHS) located along the Central Link portion of the Link Light Rail system serves the Capitol Hill neighborhood in Seattle, Washington. The West Entry and Pedestrian Concourse were constructed as part of the CHS project. The West Entry, located on… READ MORE

In March of 2014, ZGA was contacted to conduct an emergency evaluation of an apparently failing solider pile retaining wall. We were informed that wedge plates, which hold tieback anchors in tension, were apparently launching off the wall an impacting an adjacent apartment complex. Our initial evaluation… READ MORE

Working as a subconsultant to the prime engineering consultant on the project, ZGA provided geotechnical design services for the Dogwood Street bridge replacement project located in Issaquah, Washington. The project consisted of constructing a new 95 foot bridge across Issaquah Creek and associated road widening on… READ MORE

Zipper Geo Associates provided environmental consulting services at an existing retail lumber facility located in Issaquah, Washington. Our services initially included a Phase I Environmental Site Assessment (ESA). The Phase I ESA concluded the site contained an area with contaminated soil and groundwater in concentrations that exceeded… READ MORE

ZGA completed an engineering geology assessment for this proposed timber harvest area in accordance with the Washington State Forest Practices Act. The purpose of the project was to evaluate the likelihood that the proposed timber harvest would cause movement on potentially unstable slopes or deliver… READ MORE

In 1998, King County acquired the former Burlington Northern rail corridor along the east side of Lake Sammamish. The corridor would later become the missing link between Redmond and Issaquah in the County’s 44 mile trail system connecting Puget Sound in Seattle to east King County… READ MORE

ZGA provided design and construction phase geotechnical and environmental services for this new substation and three tall transmission poles that will help service the Canyon Park area. The project included a review of geotechnical reports prepared by others for the site vicinity, subsurface exploration, laboratory testing,… READ MORE

Zipper Geo Associates provided environmental consulting services in response to historical releases of dry cleaning solvents (primarily tetrachloroethylene) at two adjoining tenant spaces in this strip mall located in Bothell, Washington. The purpose of the project was to facilitate a property transaction. Our Remedial Investigation included… READ MORE