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Displaying 26 - 50 of 137

Lessons from the 2023 Southeast Turkiye Earthquakes: A Study on Damaged RC Buildings Considering the Hassan Index

June 30, 2024
Author(s)
Cemalettin Donmez, Jeff Dowgala, Meltem Eryilmaz-Yildirim, Muhammet Fethi Gullu, Lissette Iturburu, Fahri Baran Koroglu, Remy Lesquesne, Baki Ozturk, Santiago Pujol, Julian Rincon, Chungwook Sim, Matthew Speicher
A survey was conducted across 10 cities in Southeast Türkiye to classify damage in 242 reinforced concrete (RC) buildings constructed in the last 15 years, ranging from 2 to 16 stories. The 'robustness' of these buildings was quantified using ratios of

Tornado Wind Speed Maps for Building Design: Research and Development of Tornado Risk Assessment Methodology

October 2, 2023
Author(s)
Lawrence A. Twisdale, Sudhan S. Banik, Lauren A. Mudd, Marshall Hardy, Shahriar Quayyum, Fangqian Liu, Melissa K. Faletra, Peter J. Vickery, Marc Levitan, Long Phan
The first-ever engineering-derived tornado wind speed maps have been produced for the contiguous United States. Using multi-variate statistical analysis of 11 tornado and physiographic variables, we developed 9 broad tornado climatology regions. We

A DNS study of the impact of gravity on spherically expanding laminar premixed flames

September 25, 2023
Author(s)
Lukas Berger, Raik Hesse, Michael Hegetschweiler, Antonio Attili, Konstantin Kleinheinz, Joachim Beeckmann, Gregory T. Linteris, Heinz Pitsch
Determining laminar flame speeds from spherical flame experiments is dicult for low flame speeds, when the flame shapes quickly become non-spherical due to the influence of gravity. Direct Numerical Simulations (DNS) of spherically expanding laminar

A Microgravity Flame Speed Study on Refrigerant Mixtures of 2,3,3,3-Tetrafluoropropene (R1234yf) and Difluoromethane (R32)

September 25, 2023
Author(s)
Raik Hesse, Roman Glaznev, Christian Schwenzer, Valeri I. Babushok, Gregory T. Linteris, Heinz Pitsch, Joachim Beeckmann
Today's hydrofluorocarbon (HFC) refrigerants are designed to have a low global warming potential (GWP), resulting in fast atmospheric decomposition and increased reactivity. This causes them to be mildly flammable. The laminar flame speed SL,u ranks

Data Reduction Considerations for Spherical Constant Volume Flames of R32(CH2F2) with Air

September 25, 2023
Author(s)
Michael Hegetschweiler, Lukas Berger, Raik Hesse, Joachim Beeckmann, Chaimae Bariki, Heinz Pitsch, Gregory T. Linteris
The present work explores data reduction techniques for the measurement of the laminar burning velocities of R32(CH2F2)-air using a constant volume combustion device in which the pressure-time history is the only measured parameter. To allow clear

Elucidating the challenges in extracting ultra-slow flame speeds in a closed vessel - A CH2F2 microgravity case study using optical and pressure-rise data

September 25, 2023
Author(s)
Raik Hesse, Chaimae Bariki, Michael Hegetschweiler, Gregory T. Linteris, Heinz Pitsch, Joachim Beeckmann
Refrigerants with a low global warming potential (GWP) possess mild flammability. Hence, a fundamental understanding of their combustion characteristics is required to assess their fire-hazardous potential. The laminar burning velocity is one fundamental

Simultaneous Particle Image Velocimetry and Schlieren Measurements of Slow-burning Flames

September 25, 2023
Author(s)
Christian Schwenzer, Raik Hesse, Roman Glaznev, Valeri I. Babushok, Gregory T. Linteris, Heinz Pitsch, Joachim Beeckmann
The measurement of laminar flame speed is an essential factor in determining the reactivity, exothermicity, and diffusivity of a combustible mixture. In this study, the Schlieren method and Particle Image Velocimetry (PIV) were utilized simultaneously to

Assessing the Feasibility of Achieving Functional Recovery Goals through Seismic Retrofit of Existing Reinforced Concrete Buildings

September 23, 2023
Author(s)
Negar Mohammadgholibeyki, Maria Jose Echeverria, Amir Safiey, Dustin Cook, Maria Koliou, ABBIE LIEL
Damage from past earthquakes has significantly impeded post-earthquake building function, threatening community resilience, and motivating consideration of functional recovery in building design and assessment. This study examines whether it is feasible to

Flame Propagation in Blends of R152a, R134a, and R-1234yf with Air

September 13, 2023
Author(s)
Dennis Kim, Valeri I. Babushok, Michael Hegetschweiler, Gregory T. Linteris
Laminar burning velocity measurements have been made using a constant volume experiment with dry air and the refrigerant R152a (CH3CHF2), pure and blended with R134a (CH2FCF3), or R1234yf (CF3CFCH2). The resulting burning velocity data deduced from the

Backbone Curve Variations on Steel Building Seismic Response

June 2, 2023
Author(s)
Bruce Maison, Matthew Speicher, Dimitrios Lignos
A 4-story steel moment-frame building designed according to ASCE 7 was used in a numerical parameter study to assess the effects of modeling features on peak drift demands. Features studied included strength, stiffness, ductility, and degradation along

ASCE/SEI 41 Assessment of Reinforced Concrete Buildings: Comparison of the Nonlinear Dynamic Procedure with Other Evaluation Methods

May 22, 2023
Author(s)
Andrew Sen, Dustin Cook, ABBIE LIEL, Tarbin Basnet, Russell Berkowitz, Ariel Creagh, Wassim Ghannoum, Ayse Hortacsu, Insung Kim, Hamid Koodiani, Dawn Lehman, Laura Lowes, Adolfo Matamoros, Farzad Naeim, Siamak Sattar, Rob Smith
The U.S. consensus standard for seismic evaluation and retrofit of existing buildings, ASCE/SEI 41, establishes provisions for seismic analysis procedures that vary in complexity and fidelity. Although ASCE/SEI 41 provides detailed nonlinear dynamic

ASCE/SEI 41 Assessment of Reinforced Concrete Buildings: Benchmarking ASCE/SEI 41 Nonlinear Dynamic Procedures with Empirical Damage Observations

May 19, 2023
Author(s)
Dustin Cook, Andrew Sen, Tarbin Basnet, Hamid Koodiani, Ariel Creagh, Abbie Liel, Russell Berkowitz, Wassim Ghannoum, Ayse Hortacsu, Insung Kim, Dawn Lehman, Laura Lowes, Adolfo Matamoros, Farzad Naeim, Siamak Sattar, Rob Smith
ASCE/SEI 41 is the consensus U.S. standard for the seismic evaluation and retrofit of existing buildings. Although the performance-based engineering standard is based on decades of research and the result of significant vetting by ASCE and other committees

Design Guide for New Tornado Load Requirements in ASCE 7-22

January 30, 2023
Author(s)
Erik Perfetto, James Taylor, Karah Osburn, Brian O'Connor, Marc Levitan, Jennifer Mitchell
This instructional guidance is for design professionals and building officials to help them determine when a building or other structure is required to be designed to minimum tornado loads and how to calculate design tornado forces. This guide is in

Effects of Modeling Decisions on the Lateral Performance of Cold-Formed Steel Framed Walls

October 17, 2022
Author(s)
Zhidong Zhang, Matthew Speicher, Amanpreet Singh, Tara Hutchinson, Benjamin Schafer
This study proposes a modeling protocol for the lateral performance of cold-formed steel (CFS) framed wall-lines that contain both steel sheet sheathed shear walls as well as gravity walls and may include the impact of non-structural finish on these wall
Displaying 26 - 50 of 137
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