The 2001 Nisqually Earthquake severely damaged the Boeing Company’s auditorium and cafeteria building.  The building shape is very irregular in both plan and elevation.  Lateral resistance is by chevron-braced vertical frames scattered around the building.  The foundation is auger-cast piles at each column.

After the earthquake there were only minor visible indications of distress.  However, significant vertical displacement of the second-floor in the open auditorium area was noticed.  Soil liquefaction during the earthquake dragged down many of the pile-support column foundations in an uneven pattern, with a six-inch differential across the building.  Many of the foundation to column base connections were in tension due to the drag-down effect.  The resulting displacement yielded and buckled some of the chevron bracing elements of the lateral force resisting frames.

Building repair included potential of future soil liquefaction simultaneous with seismic lateral displacements.  Installation of friction dampers in series with the existing chevron bracing was chosen as the most cost-effective and quickest method for repair.  The damper slip distance was set to accommodate the simultaneous effects of seismic lateral displacements and soil liquefaction.

Non-linear time-history analysis was used to simulate response for several different design earthquake records.

Construction was uneventful and less expensive than the next least costly alternative, which would have been to disconnect and jack the building columns to relieve locked‑in settlement stresses; followed by repair and replacement of damaged lateral bracing and underpinning the braced frame foundations.  It is important to note that the client’s major concern was to minimize building closure time.  CP&A worked nights and overtime to minimize the engineering schedule and devised simple installation methods and procedures to shorten the construction schedule.  CP&A also convinced the damper supplier to shorten delivery time by reconfiguring delivery schedules on other projects.