Humans can produce significant dynamic loads, both while remaining in place and moving. Most building codes prescribe uniformly distributed static design live loads for offices, corridors, and public assembly areas such as shopping malls, airport terminals, gymnasia and dance floors. PIs' previous studies have defined forces caused by in situ activities. The objectives of the research are: (a) to define the dynamic loads generated by activities involving motion such as walking and running; and (b) to establish the benefits and efficiency of low power semiactive control technologies to mitigate excessive structural response due to phase related occupant loads. A special force platform, with a flat transfer function in the frequency range of the anticipated loads, will be constructed, instrumented and used to measure forces generated by one, two, and groups of subjects while performing prescribed activities. Loads due to individuals and groups will be characterized using analytical functions, multivariate regression analysis, and random simulation. Simulated results will be compared with measured data for small groups and design loads will be suggested both in time and frequency domains. A lightweight test floor system will be constructed in the second phase of the project. The dynamic characteristics of the floor system will be determined experimentally and analytically. The structure will be instrumented with a variable damper device. The variation in damping will be accomplished by using variable area in the damper mechanisms. The test floor will be loaded by both in situ and moving occupants and the response will be controlled using a closed loop system.
