Proceedings ArticleDOI
Axial Hysteretic Modeling of Cold-Formed Steel Members for Computationally Efficient Seismic Simulation
David A. Padilla-Llano,Matthew R. Eatherton,Cristopher D. Moen +2 more
- pp 948-959
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TLDR
In this paper, the axial cyclic response of cold-formed steel C-section structural framing members is modeled using nonlinear hysteretic springs and the model includes strength degradation, unloading stiffness degradation and pinching behavior of the observed experimental response.Abstract:
Analysis and design of cold-formed steel (CFS) structures subjected to seismic forces usually focuses on the behavior of systems such as strapped/sheathed shear walls. Experimental data from tests on these systems offers limited information concerning the seismic performance of the individual CFS components or other configurations of shear walls. Buckling and cross-sectional deformations (unique to thin-walled steel sections) highly influence the response under cyclic loading of CFS members and the associated systems. Therefore, accurate and computationally efficient hysteretic models are required to predict the seismic performance of individual CFS components and CFS buildings. Experimental data from twenty-four axial tests is utilized to calibrate a hysteretic model that represents the axial cyclic response of cold-formed steel C-section structural framing members. The model includes strength degradation, unloading stiffness degradation and pinching behavior of the observed experimental response. Model parameters and damage rules are calibrated for local, distortional and global buckling based on the hysteretic energy dissipated. The calibrated parameters can be utilized to develop a toolbox of nonlinear hysteretic springs to represent framing axial members in CFS structures for seismic analysis and facilitate performance based earthquake engineering of CFS structures.read more
Citations
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Journal ArticleDOI
Seismic Response and Engineering of Cold-formed Steel Framed Buildings
Benjamin W. Schafer,D. Ayhan,Jiazhen Leng,P. Liu,David A. Padilla-Llano,Kara D. Peterman,Matthew Stehman,Stephen G. Buonopane,Matthew R. Eatherton,R. L. Madsen,B. Manley,Cristopher D. Moen,Narutoshi Nakata,Colin A. Rogers,Cheng Yu +14 more
TL;DR: In this article, a North American effort under the abbreviated name: CFS-NEES has begun to address this challenge head on, including shear wall testing, characterization, and modeling; cyclic member testing and characterization; and, whole building shake table testing and modeling.
Journal ArticleDOI
Cold-formed steel framing walls with infilled lightweight FGD gypsum Part II: Axial compression tests
TL;DR: Wu et al. as mentioned in this paper investigated axial compressive behavior of an innovative cold-formed steel (CFS) framing wall with infilled lightweight flue gas desulfurization (FGD) gypsum.
Dissertation
A Framework for Cyclic Simulation of Thin-Walled Cold-Formed Steel Members in Structural Systems
Abstract: The objective of this research is to create a computationally efficient seismic analysis framework for cold-formed steel (CFS) framed-buildings supported by hysteretic nonlinear models for CFS members and screw-fastened connections. Design of CFS structures subjected to lateral seismic forces traditionally relies on the strength of subassemblies subjected to lateral loading of systems, such as strapped/sheathed shear walls and diaphragms, to provide adequate protection against collapse. Enabling performance-based seismic design of CFS buildings requires computationally efficient and accurate modeling tools that predict the nonlinear cyclic behavior of CFS buildings, the individual CFS components and connections. Such models should capture the energy dissipation and damage due to buckling and cross-sectional deformations in thin-walled CFS components subjected to cyclic loads such as those induced by earthquakes. Likewise, models for screw-fastened CFS connections should capture the energy dissipation and damage due to tilting, bearing, or screw shear when subjected to cyclic loading. In this dissertation, an analysis framework for CFS structures that captures the nonlinear cyclic behavior of critical components including axial members, flexural members, and screw fastened connections is presented. A modeling approach to simulate thin-walled behavior in CFS members is introduced where parameters were developed using results from an experimental program that investigated the cyclic behavior and energy dissipation in CFS axial members and flexural members. Energy dissipation and cyclic behavior of CFS members were characterized for members experiencing global, distortional and local buckling. Cyclic behavior and energy dissipation in thin steel plates and members was further investigated through finite element analysis in ABAQUS to provide a strategy for modeling steel columns cyclic behavior including local buckling. Model parameters were developed as generalized functions of the hysteretic energy dissipated and slenderness. The capabilities of the analysis framework are demonstrated through simulations of CFS wood sheathed shear wall cyclic responses validated with experimental results from full scale shear wall tests.
The cfs-nees effort: advancing cold-formed steel earthquake engineering
Benjamin W. Schafer,D. Ayhan,Jiazhen Leng,P. Liu,David A. Padilla-Llano,Matthew Stehman,Matthew R. Eatherton,R. L. Madsen,B. Manley,Narutoshi Nakata,Colin A. Rogers,Cheng Yu +11 more
TL;DR: In this article, the authors summarize a multi-year effort to advance our understanding in the seismic behavior of, and improve the design of, buildings framed from cold-formed steel (CFS), including a U.S. National Science Foundation funded project and companion industry-funded projects taken together under the abbreviated name: CFS-NEES.
References
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Journal ArticleDOI
Hysteretic models that incorporate strength and stiffness deterioration
TL;DR: In this paper, three basic hysteretic models used in seismic demand evaluation are modified to include deterioration properties: bilinear, peak-oriented, and pinching, and the models incorporate an energy-based deterioration parameter that controls four cyclic deterioration modes: basic strength, postcapping strength, unloading stiffness, and accelerated reloading stiffness deterioration.
A Beam-Column Joint Model for Simulating the Earthquake Response of Reinforced Concrete Frames
Laura N. Lowes,Nilanjan Mitra +1 more
TL;DR: In this article, the authors present a table of contents and a list of FIGURES and TABLES for each of them, including the most commonly used ones: Table 1.
Journal ArticleDOI
Characterization of CD8+ T-cell responses in the peripheral blood and skin injection sites of melanoma patients treated with mRNA electroporated autologous dendritic cells (TriMixDC-MEL).
Daphné Benteyn,An M. T. Van Nuffel,Sofie Wilgenhof,Jurgen Corthals,Carlo Heirman,Bart Neyns,Kris Thielemans,Aude Bonehill +7 more
TL;DR: Monitoring of the presence of TAA-specific CD8+ T cells infiltrating the skin at sites of intradermal TriMixDC-MEL injection and within the circulation of melanoma patients treated in two clinical trials indicates that some compartmentalization occurs after TriMix-DC therapy.
Characterizaiton of Cold-formed Steel Shear Wall Behavior under Cyclic Loading for the CFS-NEES Building
TL;DR: In this paper, the authors provide a full hysteretic characterization of OSB sheathed cold-formed steel (CFS) shear walls designed for use in the National Science Foundation funded Network for Earthquake Engineering Simulation (NEES) project: CFS-NEES.