Caltrans Updates Panel on Bay Bridge Bike Path and Tower Rods
Date: May 11, 2016
District: District 4
Contact: Leah Robinson-Leach
Phone: (510) 715-6730
OAKLAND – The new Bay Bridge Bike Path extension will be open this summer, allowing riders and pedestrians to travel from Oakland all the way to Yerba Buena Island. On Thursday, Caltrans engineers will update the Toll Bridge Program Oversight Committee (TBPOC) on what remains to be done on a redesigned section of the Bay Bridge Bike Path. They will also present corrosion protection results for a network of anchor rods in the base of the iconic white tower.
Previously approved changes to the bike path focused on the final section linking the path to Yerba Buena Island. A cantilever design replaced the original plan for a truss system, allowing for architectural harmony with the rest of the bridge. The changes added $2.5 million to the cost of the bike path, which is now expected to be completed, and open to the public, late this summer.
At Thursday’s meeting, Chief Bridge Engineer Brian Maroney will also deliver results of a testing program on the bridge’s tower anchor rods, which became the focus of attention after Caltrans engineers discovered water had intruded into the rod casings. Maroney will also submit the most feasible option to the board for protecting the rods from potential future corrosion.
More than 99 percent of the rods tested withstood the most severe earthquake-level tension they are expected to experience, however two rods were found to have stripped threads and one rod stripped to the breaking point.
TBPOC directed Caltrans to establish a tower anchor rod-testing program and adequately repair the grout. Caltrans analyzed a variety of scenarios to determine the best solution. To test various methods, life-sized models of the anchor rods, known as mock-ups, were created. The mock-ups were constructed and tested at the Caltrans Burma Road offices and in the SAS tower base. A contractor was brought onboard to construct the mock-ups and perform the tests under the direction of Caltrans engineers.
At the conclusion of the investigation, including advanced analysis and scientific testing, a team consisting of engineers and scientists from Caltrans, California Transportation Commission (CTC), Bay Area Toll Authority (BATA) and the Federal Highway Administration (FHWA) and the Toll Bridge Seismic Safety Peer Review Panel, all concluded that the rods are fit for purpose and should be grouted as soon as possible.
"An abundance of analysis and testing over the last fifteen months has proven that this tower base connection has layers of protection to provide superior safety and post-earthquake performance."
Caltrans will also present a scope, schedule and budget proposal related to assessing a cathodic protection system for the east span tower anchor rods and foundation in an effort to evaluate additional corrosion protection methods.
This Caltrans News Flash further explainins the anchor rod mock-up testing.
This video may also be viewed at: https://youtu.be/AtG4ByhYwCs.
Please visit http://www.baybridgeinfo.org for more details about the Bay Bridge project.
This News Flash is the 79th in a series of videos highlighting Caltrans' activities that present the wide-ranging and critical work that Caltrans does to enhance California's economy and livability. To see more of these and other videos, search for #CaltransNewsFlash on Twitter or visit Caltrans News Flash on YouTube (http://bit.ly/1ez3LYz).
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