Projects

The WSDOT SR 99 Tunnel Replacement Project is being completed by Seattle Tunnel Partners (STP) a joint venture team of Dragados USA and Tutor Perini.  OSG has been successfully supporting the STP joint venture since the start of the project.  OSG is providing on-site daily environmental compliance support.  OSG has also supported STP by providing specialty testing services for soil contamination and conditions in support of tunneling.