Ghassan Al-Chaar[1], Daniel P. Abrams[2]

  1. Research Structural Engineer, USAERDC, P.O. Box 9005 Champaign, Illinois 61826-9005
  2. Hanson Engineers Professor of Civil Engineering University of Illinois at Urbana-Champaign 1245 Newmark Civil Engineering Laboratory, 205 North Mathews Avenue   Urbana, Illinois 61801


This paper summarizes analytical research on stiffness and capacity evaluation of non-ductile reinforced concrete frames with masonry infill panels performed at the US Army Corps of Engineers Construction Engineering Research Laboratory. A series of nonlinear finite element analyses were completed to investigate sensitivities in behavior attributable to various design parameters. Computational simulation models were calibrated with measured data from one-story reinforced concrete frames containing one, two, and three bays. These frames were braced with either masonry or brick infill. The infill-frame structures were constructed at half-scale and subjected to lateral in-plane displacements. Modeling procedures and computed results from this investigation are summarized in this paper.

Finite element models can be employed to supplement expensive testing of large physical models provided that proper simulation exists. Once results of experimental and computational simulations are calibrated, analyses of a large array of different building configurations can be done to investigate plausible concepts for design, evaluation or rehabilitation of actual structures. Research described in this paper addresses variables significant to the determination of ultimate strength and deformation capacities for concrete frames with solid infills, and their sensitivities to variations in material properties and configuration. As well, results of this series of analyses address important variables found in laboratory tests of infill-frame systems, such as mortar type, infill type, load application points, and load distribution.

Key words: Masonry infill, non-ductile reinforced concrete frames, capacity evaluation, inplane capacity, multi-story buildings, multi-bay buildings, reduction in shear capacity due to openings, experimental and finite element study.