This report presents an experimental and computational study of two reinforced concrete beam-column assemblies, each comprising three columns and two beams. The two beam-column assemblies represent portions of the structural framing system of two ten-story reinforced concrete frame buildings. One building was designed for Seismic Design Category C (SDC C) and the other for Seismic Design Category D (SDC D). The beam-column assemblies were taken from the exterior moment-resisting frames of these buildings. The assembly from the SDC C building was part of an intermediate moment frame (IMF) and the assembly from the SDC D building was part of a special moment frame (SMF). The full-scale test assemblies were subjected to monotonically increasing vertical displacement of the center column to simulate a column removal scenario. The test was terminated when a collapse mechanism of each assembly was developed and the vertical load carrying capacity of the assembly was depleted. The primary test specimen response characteristics were measured. These included vertical and horizontal displacements at specific locations, rotations at beam ends, and strains in reinforcing bars at various locations. In addition, concrete surface strains were recorded by measuring the change in length between prepositioned targets at pre-selected critical zones of the beams. Computational analyses of the beam-column assembly tests were carried out using two levels of modeling: (1) detailed models with a large number of elements: solid elements for concrete and beam elements for both longitudinal and transverse reinforcement, and (2) reduced models with a limited number of elements: beam elements for beams and columns and rigid links connected by nonlinear rotational springs for the beam-column joints. Good agreement was observed between the experimental and computational results.
Citation: Technical Note (NIST TN) - 1720Report Number:
NIST Pub Series: Technical Note (NIST TN)
Pub Type: NIST Pubs
buildings, computational model, computer simulation, design standards, disproportionate collapse, finite element analysis, progressive collapse, reinforced concrete structures, structural robustness, testing.