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Title: Linear Analysis of Concrete Frames Considering Joint Flexibility

Author(s): Anna C. Birely, Laura N. Lowes, and Dawn E. Lehman

Publication: Commentary Reference



Appears on pages(s): 381-392

Keywords: analytical models; beam-column joints; effective stiffness; rigid offsets


Date: 5/1/2012

Linear analysis is the first—and sometimes only—analysis method used to support the seismic design and evaluation of reinforced concrete (RC) buildings. Standards such as ASCE/SEI 41-06 provide recommendations for modeling structures as part of a linear analysis. These include appropriate effective stiffness values to be used for frame members to simulate the reduced stiffness due to cracking and frame-member rigid offset lengths to be used within the beam-column joint region to simulate the increased stiffness of this zone. While significant research has been conducted to develop and validate appropriate effective stiffness values for beams and columns, comparatively little research has addressed the simulation of beam-column joint rigidity or the validation of linear analysis methods for the prediction of frame response. The research presented herein used data from prior laboratory tests of RC frame subassemblages to evaluate existing recommendations and develop improved recommendations for simulating joint flexibility to improve the accuracy of linear response modeling.