R/C Beam-to-Column Connections with Wide Beams (sponsored by NSF)

The primary objective of this research project was to determine the viability of using wide-beam RC frame construction in zones of moderate and high seismic risk. Such frames have been used successfully to reduce story heights and construction costs in regions of low seismic risk. However, there were concerns about proportioning, detailing, and the seismic response of such frames. Some of the major concerns were the permissible beam width, the percentage of beam reinforcement that can be anchored outside the column core, and whether wide-beam RC frames have adequate lateral stiffness to keep story drifts below permissible values during high seismic loading.

This research project used a combined experimental and analytical approach to answer these concerns. The experimental study consisted of six tests of beam-to-column connections constructed with the beams wider than the supporting columns. Three of the specimens represented interior connections and three represented exterior connections. All specimens were constructed at 2/3 scale and they all incorporated a floor slab and transverse beams. The analytical study used the hysteretical response measured during the tests of beam-to-column subassemblies to construct a beam model for use in dynamic response studies. Sample buildings that incorporated the use of wide-beam construction and consisted of various numbers of spans and stories were then subjected to different input ground motions.



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