Pendulum motion




Pendulum motion

San Francisco’s new “Grand Central Station of the West”, with mageba seismic isolators supporting key structural elements, will play a decisive role in getting the city moving!
The new Transbay Transit Center is currently being constructed to replace the former Transbay Terminal that was built in 1939 in downtown San Francisco. This modern transit hub, with a floor area of over one million square feet, will serve 11 transportation systems, including California’s future High Speed Rail from San Francisco to Los Angeles. Construction is expected to be completed end of 2017, with bus operations commencing early 2018. 

mageba USA has supplied eight RESTON®PENDULUM seismic isolators to support key structural elements while also protecting them against sudden ground movements – a crucial consideration for an essential transportation hub in a seismically active region such as California. RESTON®PENDULUM seismic isolators have been rigorously tested at leading international test centers, including at UC San Diego and at Eucentre in Italy – an example of which testing can be seen in this video clip.

The isolators have vertical capacities of up to 2,500 kips (11,120 kN), and are designed for horizontal forces of up to 125 kips (556 kN), with maximum displacement capacities of +/- 5.82” (148 mm) in all directions. The design of the isolators required close collaboration with the structure’s designers in addressing the challenge of the limited dimensions prescribed by the slenderness of the connecting elements. A very high standard was applied to achieving a high level of corrosion resistance, including the use of curved stainless steel sheeting for calotte sliding surfaces that are generally chromed. In addition, the isolators were designed to be easily replaceable with separate anchor plates cast in the structure to which the isolators are bolted.

But that is not where mageba’s involvement in the construction of this special structure ends: contracts have since been signed for the design and supply of RESTON®SPHERICAL bearings and TENSA®MODULAR expansion joints – high-quality, highly reliable structural components that will for many years help this critical transportation hub to perform like clockwork!


The lower part of a RESTON®PENDULUM seismic isolator, with separate anchor plates for easy removal/replacement, prior to final assembly


A RESTON®PENDULUM seismic isolator, secured on a pallet for transport to site


A row of RESTON®PENDULUM seismic isolators in position at the Transbay Transit Center


Installation of a RESTON®PENDULUM seismic isolator


Watch a short video of testing of a RESTON®PENDULUM seismic isolator


Rendering of the new Transbay Transit Center in San Francisco, California


Representation (cut-out view) of a RESTON®PENDULUM seismic isolator, showing the spherically-shaped calotte at its heart which accommodates rotations


The RESTON®PENDULUM seismic isolator has been extensively tested at leading international testing centers