San Pablo Bay, Contra Costa and Marin Counties
Scope of Work
- Survey services associated with the quality assurance program for the seismic retrofit of the bridge, including construction layout for bolt patterns on every retrofit pier jacket (as many as 30 holes each on more than 50 jackets). The precast pier jackets were essential to strengthen the bridge support system.
- Performed a control survey that allows Caltrans to monitor any future bridge movement that could result from an earthquake.
- Install massive precast concrete jackets on each pair of bridge support piers, which would involve drilling holes through the existing bridge support structure using the jacket bolt patterns to guide the drilling operation. The bolt hole needed to line up with a corresponding hole in the jacket on the other side of the support structure. A significant portion of this operation would be performed underwater by divers.
- Obtain precise measurements of the bridge piers from a control survey performed across the San Pablo Bay, understanding that the bridge is subject to lateral movement caused by high winds, tidal forces, wave action, heavy traffic and expansion/contraction of the steel superstructure.
Solutions and Successes
- Brelje & Race developed a survey protocol in that involved collecting data of each entry and exit hole of the jackets, then wrote a custom program routine to translate the raw data that could be used to precisely position and align the bolt holes drilled into the bridge piers. The result provided consistent results that ultimately saved the Client both time and money, as well as assisted divers with their underwater drilling operations.
- Brelje & Race also performed a control survey using over 100 survey disks that would allow Caltrans to check for bridge pier movement in the event of an earthquake or shipping accident.
Other Notes of Interest
Winner - CELSOC Engineering Excellence Awards - 2007 Project of the Year
“With Brelje & Race on our team, we were rewarded with greater project efficiency and safety during the pier jacket installation process. Their quality assurance surveys of the pier jack bolt patterns reduced bolt-hole reaming and dive time for underwater bolt assembly. They also demonstrated foresight and capability to perform a control survey of a greater precision than strictly traditional surveying equipment and methods would have yielded. Brelje & Race’s exceptional attention to detail, ability to work side by side with other subcontractors, and technical expertise played a critical role in the success of this unique and challenging project.” Jack Frost Senior Vice President Tutor-Saliba Corporation