Nonlinear Dynamic Analysis of Frames with Filler Panels

The bond between filler panels and a building frame is often destroyed by shrinkage or poor construction techniques, causing small gaps that open and close during ground motions. An analytical model and a computer program were developed for nonlinear dynamic analyses of plane frames with filler panels having such gaps at the sides and tops of the panels. Beams and columns of the frame were represented by plane-frame elements. Filler panels were modeled by rectangular finite elements having various nodal displacement patterns. Criteria were devised for monitoring the opening and closing of gaps, and a procedure is described for modification of the stiffness matrix upon closing and opening of the gaps. Sample problems show that the presence of small gaps between frames and filler panels can significantly affect the dynamic responses of structures subjected to ground motions.