New Precast Concrete Moment Connections under a Column Removal Scenario

Published

September 22, 2025

Author(s)

Malcolm Ammons, Jonathan Weigand, Travis Thonstad

Abstract

This technical note presents an experimental investigation of the performance of five novel precast concrete moment-resisting connections subjected to a simulated column removal scenario. The objectives of the investigation were 1) to characterize the behavior and failure modes of the connection assemblies and 2) assess their viability for use in precast concrete construction to achieve robust performance against disproportionate collapse. The tested assemblies were derived at a five-eighth scale from a 10-story prototype building and consisted of two half-span spandrel beams connected to a central column. The assemblies were designed specifically for moments induced from the loss of an exterior column in the prototype building. A capacity design approach was taken to concentrate inelastic action in designated components at the beam-to-column interface. Each assembly was subjected to monotonically increasing vertical displacement applied to the unsupported column until connection failure. The assemblies were extensively instrumented to measure the vertical force applied to the assembly, displacement at different locations along the beams and column, in-plane rotations of the precast concrete components, and strains in the reinforcing bars and steel connection components. All the assemblies failed as was intended by design, with rotational deformations concentrating in designated ductile components until their eventual failure. A computational methodology was used in conjunction with the experimental results to evaluate the structural robustness of the assemblies against sudden column loss. All the assemblies were shown capable of withstanding loads greater than the applicable gravity loading that they would need to sustain to prevent collapse under sudden column loss. Although the threaded rod connection assembly's connections were the easiest to make in a laboratory setting, all the connection concepts were proven viable for use in precast concrete construction, with each concept having unique advantages and disadvantages.

Citation

Technical Note (NIST TN) - 2348B

Report Number

2348B

NIST Pub Series

Technical Note (NIST TN)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/NIST.TN.2348B

Local Download

Keywords

Connections, disproportionate collapse, experimental, moment-resisting connections, precast concrete, progressive collapse, robustness.

Citation

Ammons, M. , Weigand, J. and Thonstad, T. (2025), New Precast Concrete Moment Connections under a Column Removal Scenario, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.TN.2348B, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=960673 (Accessed October 8, 2025)