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.