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Green Valley Road OC

By:confab

The longest single piece precast prestressed concrete bridge girders manufactured in California were installed during a warm August 2015 night for the construction of the Green Valley Road Overcrossing structure in Cordelia, California.  The girder shape chosen during type selection for this bridge was the relatively new California Wide Flange which was adopted by Caltrans as a standard section in 2012.  For the Green Valley Road structure, Con-Fab California Corporation fabricated girders that were 7’-6” deep x 166’-5” long, weighing 217,000 lbs each.

Contemporary highway bridge designs are incorporating longer spans which are supported by ongoing advances in concrete and reinforcing technologies.  The CA Wide Flange section was specifically developed to meet the demand for designs with longer clear spans and wider girder spacings for precast bridge structures that are cost competitive with cast-in-place box girder construction. The use of the California Wide Flange Girder in California highway bridge construction has increased demonstrably each year since its adoption by the State which reflects favorably on the cost effectiveness of this section.

While the materials science and fabrication processes are in place to supply this cost effective bridge element, a very important consideration for the use of long precast girders is the identification of any transportation constraints. Extremely long bridge girders can be delivered to most destinations around the State.  However the more remote sites do require a transportation route analysis to confirm the product can be delivered.  California bridge girder manufacturer’s welcome all information requests from designers regarding the ability to deliver long girders to specific sites.

The Green Valley Road Overcrossing structure is a part of a multi-year, multi-phase transportation project conducted by Caltrans, The Solano Transportation Authority, and the Metropolitan Transportation Commission to provide major improvements to the Interstate 80, Interstate 680 and State Route 12 interchanges. The project will benefit citizens by improving travel times, reducing cut-through traffic on local streets, and enhance safety by streamlining connections for motorists transitioning between these three major state routes linking the Bay Area, the Napa Valley, and Sacramento.

 

Project Name:  Green Valley Road OC

Location: Cordelia, California

Owner: The State Of California and the Solano Transportation Authority

Engineer: Mark Thomas and Company, Inc + Nolte Associates

Prime Contractor:  DeSilva Gates Construction

Bridge Subcontractor:  Viking Construction

Precast Subcontractor:  Con-Fab California Corporation

Building CA 3E

By:confab

The shell construction of Building CA 3E at Lam Research Corporation’s Fremont, California campus is nearing completion for delivery to the owner in April 2016.  This unique structure supports Lam Research’s core business as an innovative supplier of wafer fabrication equipment and services for the global semiconductor industry.

Thirty 8 inch thick precast prestressed concrete wall panels, measuring 12 feet wide by up to 50 ft tall, were used to enclose two elevations of the structure.  In their final position, these non-load bearing wall panels are laterally supported at three points: at the foundation; at the mezzanine level located 18 ft above the base; and at the fan deck located 49 ft above the ground. The utilization of prestressing accommodates a building geometry that requires the panels to span 31 ft from the mezzanine to the top of panel in a high seismic region.  The performance demand was further elevated by a project specific seismic design criterion specifying an importance factor of 1.5, thereby increasing the seismic design loads by 50% when compared to an ordinary structure.  The inherent benefits of prestressing the panels also simplified the shipping and handling operations.

This project was built on an existing, operating campus with significant limitations to the space available for the contractor’s use.  The construction zone was not significantly larger than the footprint of the new building.  Offsite production of the wall panels allowed fabrication concurrent with jobsite construction activities and mitigated adverse impacts to the construction sequence, schedule and space that would have occurred with site cast walls, providing yet another example of the benefits associated with precast building elements.

 

Project Name:  Building CA 3E

Location: Fremont, California

Owner: Lam Research Corporation

Architect: Devcon Construction, Inc.

Engineer:  Biggs Cardoza Associates, Inc.

Prime Contractor: Devcon Construction, Inc.

Precast Subcontractor: Con-Fab California Corporation

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