The Laguna Interchange is part of the 26-mile long Eastern Transportation Corridor (ETC) Toll Roads in Orange County. The double interchange forms the union of the State Route 241 with Interstate 5 and State Route 133. It involves 11 bridges among a total of nearly 60 similar bridges within the Corridor. Mr. Tamannaie was the Task Manager for the design of this interchange as well as another bridge in the Corridor, El Camino Real Overcrossing. Segments of this design build project were completed between 10 to 14 months ahead of schedule and it won numerous awards from various professional societies, including:

• Project of the Year Award by the Orange County Branch of the American Society of Civil Engineers
• American Concrete Institute's (ACI) 1999 Engineering and Design Award
• The American Consulting Engineers Council's 1999 Engineering Excellence award
• The Consulting Engineers and Land Surveyors' Excellence in Engineering and Grand Awards
• The Orange County Engineering Council's Engineering Project Achievement Award
• The Build America Award for Excellence by the Associated General Contractors and AON, Inc.

Mr. Tamannaie managed the Federal Demonstration Project for widening of Lawrence Expressway for HOV lanes in Santa Clara County. The project involved widening and seismic retrofit of Stevens Creek Boulevard Undercrossing and El Camino Real Overcrossing. This project won the South Bay Chapter of American Public Works Association's Public Works Project of the Year Award in 1997.

Mr. Tamannaie designed the Barranca Parkway HOV Drop Ramp project, a bridge supporting an HOV ramp that makes a T-intersection with an existing overcrossing structure in the median of State Route 5 in Orange County. The bridge and its mechanically stabilized embankment (MSE) approach structure form a unique structural and aesthetic design. The designation of "drop ramp" entered the Caltrans lexicon with this type of bridge, built on the California highway system for the first time. The project received Caltrans's 1993 Excellence in Transportation Award in the category of Best Operational Improvements.

Mr. Tamannaie Served as the Project Manager for a segment of a fast-track Caltrans project, funded by LACMTA, for completion of SR 30 in Los Angeles county. The project included 15 bridges, five of which were designed by Mr. Tamannaie's team. The suspended Marshall Creek Flume, carries the flood channel over the 10-lane depressed freeway. The latter is a unique, complex, and large self-supporting prestressed concrete box structure carrying truck traffic on top and the load of the existing floodwater channel severed by the freeway alignment. This structure was presented at The 2002 International Bridge Conference as a unique water conveyance structure and has been used as a model for similar projects.