Lerch Bates Inc. Building Insight

Global Leaders in Technical Consulting for the Building Industry

Earthquakes and Elevators

In March 2010, I had the unique opportunity to review earthquake damage on 11 traction elevators located in two hotels in Santiago, Chile.  On Sunday, February 27, 2010 at approximately 3:30AM, and lasting for nearly four minutes, an 8.2 Richter earthquake struck near Santiago Chile. Damage was extensive to many buildings and a loss of life was experienced in and around the epicenter, which was about 130 miles from Santiago.

The two hotels, while in close proximity to each other were very different; one was older and low rise while the other was newer and higher rise. The first, an 8-story low-rise hotel included six traction elevators; three passenger and three service.  All elevators were installed in 1965. The second, a 24 story high-rise hotel included five traction elevators; three passenger and three service.  All elevators were installed in 1998.

After the quake, in the 8-story hotel, each of the six traction elevators had the counterweight assemblies come out of the rails.  Fortunately, the hotel had a seismic monitoring device that automatically stopped the elevators at the next floor when seismic activity was first detected.  This feature, which worked just as designed, prevented more damage to the elevator cars like counterweight frames crashing into the car tops.

In the 24-story hotel no counterweights came out of the guide rails.  These elevators were also equipped with a seismic detection instrument that immediately placed the cars out of service when seismic activity was detected. One of the passenger cars had its hoist cables come out of the 2:1 car top sheave grooves while the car was in motion.  The hoist cables had to be replaced.    Other than that, no damage occurred to the cars with bracket spacing at 1.8 meters.

The biggest cause of damage to the elevators occurred with a 6 inch waterline on the top floor of the 8 floor hotel ruptured allowing water to flow across the floor for two hours running down the passenger elevator shaft.  This caused failure of the microprocessor boards on top of the car (Mitsubishi locates their car controller on the car top).  It also damaged door operators and caused flooded pits.

The lessons I learned from this experience were:

  • Lesson 1: in earthquake zones, always equip the elevators with seismic detection instruments to immediately stop the car.
  • Lesson 2:  Guide rail brackets should be spaced more closely together.  All of the counterweights derailed in the hotel with bracket spacing of 4.0 meters but none of the counterweights derailed with bracket spacing of 2.0 meters.
  • Lesson 3:  All sheaves should be equipped with rope restraints eliminating the ability of the ropes to jump grooves.
  • Lesson 4:  Always know where the shut off valves are located for major water pipes in the building.  While this is not an elevator related piece of equipment, it would have prevented the significant damage to the electrical boards.

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