Thesis
Effects of dynamic amplification of occupant loads on floors and decks
Washington State University
Master of Science (MS), Washington State University
05/2020
DOI:
https://doi.org/10.7273/000004067
Handle:
https://hdl.handle.net/2376/125188
Abstract
Dynamic occupant loads create significantly higher demands on structures than static loads and are often unaccounted for in the design of floors and decks. This study comprised two parts. First, recent interior floor collapses reported throughout the United States were investigated for possible causes and design recommendations were provided. Second, the span rating methodologies for deck boards used in the construction of outdoor decks and balconies were studied, resulting in suggested changes in the policies. Dynamic overloads caused 15 floor collapses, which were investigated to identify common threads, make recommendations to reduce future collapses and suggest avenues of continued research. From the research, it was identified that most failures occurred in multifamily structures within 1.6 km (1 mi) of a university in the southeastern United States. Notably, sixty percent of failed floors were framed using metal-plate connected wood trusses. Living spaces of multifamily structures in close proximity to universities are recommended to be designed above code minimums to counteract rhythmic loading. Pairing this with campus education on the dangers of floor overloading is recommended to mitigate collapse risk until more research is conducted. The American Lumber Standard Committee (ALSC) publishes a Policy for Evaluation of Recommended Spans for Span Rated Decking Products (ALSC 2004). This policy was critically reviewed and suggested changes were provided to the current ALSC policy regarding the concentrated load requirement and testing procedure. It is recommended that span ratings for deck boards are developed using a minimum concentrated load of 300 lbs applied over a 4" by 4" area with a load duration factor of 1.0. Currently, ALSC policy requires deck boards be tested in a two-span load condition with the concentrated load applied to one span. It is recommended that this test be conducted in a similar fashion, but with deck boards fastened with typical fasteners to simulated deck joists. The boundary effect of testing with these fasteners (rather than idealized pin-roller conditions) was quantified and recommended to be incorporated into the ALSC policy.
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Details
- Title
- Effects of dynamic amplification of occupant loads on floors and decks
- Creators
- Madison Ann Broers
- Contributors
- DONALD A BENDER (Advisor) - Washington State University, Composite Materials and Engineering Center
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Civil and Environmental Engineering
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900890790901842
- Language
- English
- Resource Type
- Thesis