Mr. Tamanaie managed design of the structures in this Los Angeles County I-405 interchange, including two connector ramps, a complex widening combined with a sidehill viaduct approach structure, soundwalls, and retaining walls. Congestion and limited space required innovative design features such as tight bridge alignment radii and deep shaft foundations and outrigger bents. This was one of the first projects of its kind to be funded privately and constructed by Caltrans.

Mr. Tamannaie managed the design of North Bend Drive Bridge over Main Drainage Canal. This bridge is a 118-foot long, three span concrete slab bridge on concrete pile extensions, designed and constructed according to Caltrans specifications and standards. As part of the project, the bridge was designed to carry a large waterline externally and the channel bed was lined with concrete.

Mr. Tamannaie was responsible for leading the design of 2 bridges over Pleasant Grove Creek, as part of Fiddyment Ranch development, in Roseville California. These bridges are:

• Fiddyment Road Bridge over Pleasant Grove Creek, a four-span, cast-in-place, prestressed concrete box girder bridge on multicolumn bents. This bridge housed multiple utilities for the development.
• Blue Oaks Boulevard Bridge over Pleasant Grove Creek, a 120-foot long, three span concrete slab bridge on concrete pile extension bents.

Mr. Tamannaie was in charge of the structural improvements for Anatolia Residential Development and Infrastructure Project, Rancho Cordova, California. Project structures included a utility bridge, as well as sewer, water and drainage facilities. The bridge designed was a multispan precast, pretensioned concrete girder bridge on large diameter CIDH pile shafts with a length of approximately 300 feet to support a water and sewer crossing over the Folsom South Canal. One of the other significant structures for the project was an underground reinforced concrete sewer lift station with dimensions of 20’ by 20’, buried 40’ deep in the ground, housing two powerful pumps inside for forced flow.

Mr. Tamannaie was the Bridge Project Engineer for type selection and final design of the Willow Springs Bridge, a maintenance structure for the City of Folsom that also carries water and sewer pipes for the development project. A single-span, prefabricated steel truss bridge, with a span of 130 feet, manufactured by Excel Bridge Company was selected. The abutments and pipe supports were designed for the bridge, and the bridge and its concrete deck design were reviewed. The bridge was delivered to the site in two segments, erected on falsework, assembled, released and decked over for service.

Through a contract with Intel, Mr. Tamannaie was assigned the seismic analysis of the newly constructed Interconnect Link, a multispan, enclosed pedestrian skyway connecting two of the Intel's campus buildings. This private facility, founded on single-column pile shaft bents, crosses the City of Santa Clara's Juliet Street's right-of-way. As required by the City, the skyway, having been designed by others according to the UBC, was analyzed to confirm that it met the Caltrans "No Collapse" seismic criteria. The structure was analyzed expeditiously using the Caltrans methods for seismic and pile shaft stability analyses as the construction of the new corporation's campus was nearing its completion. It was determined that the skyway, while subject to large permanent deformations due to rotation of its shaft foundation, would not collapse catastrophically after the maximum credible seismic event. This resulted in the City's approval of the project and issuance of permit to cross its right of way.

Mr. Tamannaie led the effort for analysis and mitigation of flood scour damage sustained by the Tracy Bridge, the power plant's access over the Truckee River in Nevada. The foundation of this steel through-girder bridge was heavily eroded by the floods of 1997, reducing the load bearing capacity of the bridge considerably. In two reports, the condition and load-bearing capacity of the bridge and repair and replacement options were discussed. The bridge pier area was dewatered for visual inspection of the extent scour and rock riprap was placed around it. The bridge was subsequently posted with new load limits.

Mr. Tamannaie led the Analysis to determine the cause of collapse of the Chili Bar Bridge over the American River in El Dorado County. This 1930s-era concrete arch bridge had collapsed during its removal, plunging equipment and operator down into the river. The process of staged bridge removal was simulated using computer models until collapse was reached. By looking at the state of bridge member stresses right before collapse, it was determined that the arches, being of lower quality and compressive strength concrete, had been pushed beyond their confinement stress limit and reached a state of sudden failure. This failure was similar to that of compressive bridge members under seismic conditions. A report was submitted for these findings.

Mr. Tamannaie provided design modifications through a Cost Reduction Incentive Proposal (CRIP) for a very a large double box culvert under the ten existing lanes of I-10 in San Bernardino County. Initially designed to be built in several stages using traffic detours, the structure was redesigned during construction using short nighttime freeway closures. Sheetpiling was driven to serve as the walls of the culvert and a slab poured with quick-set concrete on the existing ground as its top deck. This procedure allowed the opening of the freeway for the morning rush traffic. Subsequent to the night operations, the earth bound by the walls and deck was mined, reinforced concrete walls were poured against the exposed sheetpiling, and an invert slab was poured to create the required culvert and waterway. This change through the CRIP process was reached in record time, saved the Contractor and Caltrans thousands of dollars in traffic control, resulted in a safer project and allowed the contractor to meet his contractual time obligations.