This research tested a series of three one-quarter scale two bay by two story frames under static and dynamic loads. The research considered the ability of frames with different reinforcement designs to develop resistance mechanisms, and evaluated the effective dynamic increase in response when a frame was loaded dynamically. The static tests were slowly loaded through a hydraulic actuator at the location of the removed column. The dynamic test was loaded with additional dead weight and the center supporting column suddenly removed to simulate a collapse scenario. The dynamic loads and strains in the horizontal direction were 1.3 to 3.4 times greater than the corresponding static loads. Subsequent analysis of the test data and results from static simplified analyses and dynamic single degree of freedom (SDOF) models showed that there is a very fine tipping point at which the structure is pushed past the compressive arch or flexural range of response into the catenary action range of response. At this point the dynamic effects increase significantly due to a snap through type of effect.
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