RC moment-resisting frames (RCMRFs) have commonly been used for low-to-moderate rise buildings in
seismic prone regions. RCMRFs can perform well when they are subjected to strong earthquake ground
motions if they are properly designed and detailed
to dissipate the seismic input energy through
deformations in inelastic range. The connections between beams and columns thus become critical
components to the performance of these structures.
In conventional RCMRF connections, the width of the beam does not exceed the width of the column.
Adopting a flat beam system for the design scheme provides many advantages, such as the reducing the
amount of formwork required, the simplicity for repetition, and the decrease of the required story height.
RCMRFs with flat beams have been used extensively, despite the lack of sufficient information on how
this system behaves under earthquake loading which leads the codes to restrict the use of flat beamcolumn
connections in earthquake prone regions.
