An Experimental and Computational Study of Precast Concrete Moment Frames under a Column Removal Scenario

Published: September 22, 2015

Author(s)

Joseph A. Main, Yihai Bao, Hai S. Lew, Fahim Sadek, Vincent P. Chiarito, Stephen D. Robert

Abstract

This report presents an experimental and computational study of two precast concrete moment-frame assemblies, each comprising three columns and two beams. The two moment-frame assemblies represent portions of the perimeter moment frames of two 10-story precast concrete frame buildings. One building was designed for Seismic Design Category B (SDC B) and the other for SDC D. The assembly from the SDC B building was part of an ordinary moment frame (OMF), and the assembly from the SDC D building was part of a special moment frame (SMF). The full-scale test specimens were subjected to monotonically increasing vertical displacement of the unsupported center column to simulate a column removal scenario. The tests were continued beyond the ultimate capacity of the assemblies to characterize the failure modes and collapse mechanisms that were developed. Experimental measurements included the vertical load, vertical and horizontal displacements at specific locations, rotations at beam ends, and strains in reinforcing bars and other steel components. In addition, video cameras recorded the progression of damage, including surface cracking, spalling, and component failure in the regions surrounding each moment connection. The failure of both the OMF and the SMF assemblies was characterized by (1) fracture of the bottom anchorage bars at the welded connection to the center column and (2) diagonal cracking and shear deformation of the end columns under outward forces generated by arching action in the beams. Other failure modes that were observed included shear stud failure for the OMF specimen and bond failure of anchorage bars for the SMF specimen.
Citation: Technical Note (NIST TN) - 1886
Report Number:
1886
NIST Pub Series: Technical Note (NIST TN)
Pub Type: NIST Pubs

Keywords

buildings, computational model, computer simulation, design standards, disproportionate collapse, finite element analysis, moment resisting connections, progressive collapse, precast concrete structures, structural robustness, testing.
Created September 22, 2015, Updated November 10, 2018