MCEER DEMONSTRATION HOSPITALS
MATHEMATICAL MODELS AND PRELIMINARY ANALYSIS RESULTS
Authors: Tsung Yuan Yang, Andrew Whittaker
Publication Date: February 2002
Abstract:
This report presents structural-engineering information on three medical facilities: two located on the West Coast of the United States and one located on the East Coast. The three facilities have the same plan and vertical geometry: a geometry that is based on an existing facility in San Fernando Valley, in Southern California.
The structural-engineering information was prepared using as-built data from the existing facility in the San Fernando Valley. This facility was constructed in the early 1970s to meet the seismic requirements of the 1970 Uniform Building Code (ICBO, 1970). For the intended purpose of the demonstration hospitals, the framing system of the existing facility was modified slightly to a rectangular plan profile and the penthouse atop the existing facility was eliminated. The vertical shafts in the building for mechanical and vertical transportation systems were replaced by typical floor framing. The resulting building is termed West Coast 1970s (or WC70) in this report.
The Uniform Building Code was used for seismic design in California from the late 1920s through to the time of the introduction of the 2000 International Building Code in 2001. In the late 1960s, the Uniform Building Code was substantially revised. Limits on allowable displacements in buildings were introduced in the 1976 edition of the Uniform Building Code (ICBO, 1976). This change led to substantial increases in the required elastic lateral stiffness, and subsequently the lateral strength, of moment-frame buildings such as the existing facility. As such, the stiffness and strength of mid-to-late 1970s moment-frame construction are significantly greater than those of 1960s construction.
The MCEER Hospital Project serves in part to integrate work on characterization and retrofit of structural and non-structural components and systems. To enable those investigators tasked with developing retrofit strategies for structural components and systems to prepare solutions for weak and flexible buildings similar to those constructed on the West Coast in the 1960s, the authors developed a framing system that complied with the gravity-load and seismic requirements on the 1964 Uniform Building Code. That framing system was designed for the same gravity loads as those used for the design of the existing facility. The resulting framing system is termed West Coast 1960s (or WC60) in this report.
Medical facilities on the West Coast have been designed for earthquake effects for more than 60 years. Such effects were not considered for the design of East Coast medical facilities until the 1990s. As such, there is a large inventory of medical facilities on the East Coast that have minimal resistance to earthquake effects. To facilitate the preparation of retrofit strategies for a typical (vulnerable) 1970s East Coast medical facility, beam and column sizes for the third framing system were developed to comply with the requirements of the 1970 Building Code of New York (Merritt, 1970). This code had no seismic design requirements, and framing systems that complied with the Code were designed for gravity and wind loads only. The framing system was designed for the same gravity loads as WC70 and WC60. The resulting framing system is termed East Coast 1970s (or EC70) in this report.
Full Report:
SAP Input Files: