District Engineer, Ewa Z. Bauer - Golden Gate Transit

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Board of Directors Agenda Item No. 6.C. Meeting of August 10, 2012 Page 6 On November 21, 2008, the District submitted the 2008 Biennial Bridge Inspection Report and the Load Ratings for the Golden Gate Bridge, Bridge No. 27-0053, to Caltrans and FHWA. On April 6, 2012, the District submitted the “National Bridge Inventory – Structure Inventory and Appraisal” reports for the Lincoln Boulevard Overcrossing, Toll Plaza Undercrossing, Alexander Avenue – Bunker Road (Overpass), and Alexander Avenue – East Gate Road (Overpass) to Caltrans and FHWA. On April 19, 2010, staff began the 2010 Biennial Bridge Inspection. The inspection of Span 2 was completed in September 2010. The inspection of Span 3 was completed in February 2011. The inspection of Span 1 was completed on April 29, 2011. Inspection of the available portions of the North Approach Viaduct was completed on October 21, 2011. Inspection of the South Approach Viaduct was completed on December 13, 2011. Inspection of the Fort Point Arch and South Anchorage Housing were completed on January 4, 2012. Inspection of both the North and South Towers was completed on June 1, 2012. On August 10, 11, and 12, engineering staff met with representatives from FHWA and Caltrans to review the District’s bridge inspection plan and the latest federal requirements concerning mandatory bridge inspections. Staff is revising various aspects of the plan to reflect these requirements. On December 2, 2011, the District responded to a request for information from Caltrans relating to FHWA and Caltrans’ review of the District’s bridge inspection plan. Staff is finalizing a Request for Proposals to engage a consultant to perform an underwater inspection of the Golden Gate Bridge South and North Tower Piers. On March 12-15, 2012, engineering staff participated in FHWA training for Fracture Critical Bridge Inspection Techniques for Steel Bridges. All participants passed the certification examination. On April 16-19, 2012, engineering staff participated in FHWA’s on Bridge Inspection Refresher Training course. All participants passed the certification examination bringing the District into full compliance with FHWA requirements for bridge inspector training. Golden Gate Bridge Main Cable Access System. Access staging for the lower/mid-span portion of both cables, where it can be supported directly from the bridge sidewalk, has been erected. The Engineering Department is preparing a Request for Proposals to procure access to the upper portions of the Main Cables. Seismic Instrumentation. The State of California, Division of Mines and Geology – Strong Motion Instrumentation Program (SMIP) has completed installing and testing the Phase I seismic instrumentation system. Seventy-six seismic sensors and two recording stations were installed as part of this phase. On April 10, 2001, and September 21, 2004, the Seismic Instrumentation Advisory Panel (Panel) approved the Phase II sensor locations for the South Approach Structures. Twenty-five additional sensors were proposed for the South Approach and were included as part of the Phase II Seismic Retrofit project. On September 24, 2002, the Panel approved the design plans for the Phase II Seismic Instrumentation, North Approach Structures. Twenty-four additional sensors for the North Approach were added to the Seismic Instrumentation System. Subsequent panel
Board of Directors Agenda Item No. 6.C. Meeting of August 10, 2012 Page 7 meetings were held on September 30, 2003, September 21, 2004, and October 25, 2006, to review the progress on construction of the Phase II Seismic Instrumentation and the MEMS system developed by the U.C. Berkeley Citris program. The MEMS has been tested with satisfactory results and was removed by U.C. Berkeley in March 2007. On October 25, 2006, the Panel recommended installing a wind monitoring system on the Golden Gate Bridge. On April 27, 2007, the Board authorized SMIP to install the wind monitoring system, including an anemometer and a seismic recorder connected to selected, existing and new seismic sensors on the Suspension Bridge. On August 29, 2007, the Panel approved the design of the wind monitoring system, and recommended measuring ambient vibration and analyzing the bridge computer model with data recorded from the 1999 Bolinas and 2000 Napa earthquakes. The wind monitoring system was completed in October 2008. On June 28, 2010, a small nearby earthquake triggered the sensors and recorded the earthquake. Earthquake Response Plan. Staff has developed an Earthquake Response Plan. Engineering staff is developing a program for a refresher course on performing post-earthquake bridge inspection in accordance with the Earthquake Response Plan. In 2002, SMIP installed an independent seismic sensor with a warning light and buzzer in the Sergeant’s control room. On March 1, 2007, the Bridge Earthquake Response Pager System successfully recorded and transmitted the Lafayette Earthquake with a 1%g ground acceleration at the bridge. On October 30, 2007, the Bridge Earthquake Response Pager System successfully recorded and transmitted the Alum Rock Earthquake with a 1%g ground acceleration of the bridge. On July 7, 2012, the Pager System was tested with satisfactory results. On March 5, 2012, a 4.0 magnitude earthquake occurred on the Hayward fault near El Cerrito. The ground acceleration registered at the Bridge was insignificant to trigger the Bridge Earthquake Response Pager System. In accordance with the triggering criteria described in the “Bridge Earthquake Response Plan,” a Level 1 inspection was performed by Sergeant’s Office personnel with video cameras and a driving inspection of the roadway. It was determined that there was no damage to the bridge caused by the earthquake. BUS TRANSIT FACILITIES Novato Bus Facility Security Improvements, Contract 2012-BT-6. Staff prepared design plans and bid documents for security improvements at the Novato Bus Facility. The project was advertised for construction bids on November 15, 2011, and on December 20, 2011, six bids were received and opened. On January 27, 2012, the Board authorized award of the Contract to the low bidder, Massa Construction Co., Inc., in the amount of $568,215. The Notice to Proceed was issued effective February 13, 2012. The contractor has completed installation of the electrical rough-in. A new concrete ramp and pathway outside of the Dispatch Building has been constructed. The new bus driveway sliding security gate and the employee driveway swing gates have been installed. The installation of the new perimeter security fencing is complete. Installation of the new electrical panels, gate openers, and electronics continues.
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District Engineer, Ewa Z. Bauer - Golden Gate Transit

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