Metal Building Systems make up a large portion of new low-rise, non-residential construction today. These systems are designed to be extremely efficient and as such exhibit very different behavior than other steel building systems. The current building codes lump Metal Building Systems in with other types of steel building systems in terms of their design criteria.
Through support of the Metal Building Manufacturers Association, the Network for Earthquake Engineering Simulation, and the American Iron and Steel Institute, three Metal Building System specimens will be tested to determine the seismic response of various configurations. The first specimen will be a typical Metal Building System with metal panel side walls. The second specimen will have pre-cast tilt-up concrete sidewalls. The third will have a concrete floor mezzanine attached to one side as well as a tilt-up sidewall.
The full-scale specimens will represent the interior of a 20 ft. high metal building with 18 ft. bay spacing and 60 ft. span length. The response of each specimen will be used to calibrate models for a FEMA P695 study which will determine appropriate design criteria for these unique building systems.
Results
Each specimen was subjected to a series of ground motions with increasing magnitude until the specimens were damaged to a state which precluded further testing. Although it is thought that metal buildings lack ductility, preliminary results suggest that metal building systems generally have a high level of system overstrength and will perform excellently under the most demanding ground motions. But test results of the first two specimens showed that attaching heavy walls to the metal building would reduce the safety margin against collapse. Testing from the third specimen provided data for calibrating a proposed procedure to distribute seismic load to the frame and mezzanine. In addition, this test investigated alternate energy dissipation mechanism. The results will be used to calibrate numerical models for the development of design criteria.
