Publications de Ahmed Mohamed Ahmed Elkady

The use of ductile steel fuses for the seismic protection of acceleration sensitive non- structural components: Numerical and Experimental verification

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Recent seismic events have showcased the vulnerability of non-structural components to even low- or moderate-intensity earthquakes that occur far more frequently than design-basis ones. Thus, community-critical buildings, such as hospitals, telecommunicati ...

EEME2023

Proposed Panel Zone Model for Beam-To-Column Joints in Steel Moment Resisting Frames

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady, Andronikos Skiadopoulos

In capacity designed steel moment resisting frames (MRFs), beam-to-column joints (i.e., panel zones) are designed to remain elastic. To potentially exploit the beneficial aspects of the stable panel zone hysteretic response in shear, a robust panel zone mo ...

2023

Analytical Studies in Support of an Improved Approach to the Design of Acceleration-Sensitive Nonstructural Elements

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper summarizes a series of analytical studies that were conducted in connection with an improved approach for the design of acceleration-sensitive nonstructural elements. In the new approach, bracing to secure nonstructural elements to the structure ...

Applied Technology Council, Sponse2022

Experimental Study to Validate an Improved Approach to Design Acceleration-Sensitive Nonstructural Components

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Nonstructural components in buildings can be subjected to very large acceleration and deformation demands during earthquakes. This is particularly true for flexible components that are tuned or nearly tuned to one of the modal frequencies of the supporting ...

Applied Technology Council, Sponse2022

EaRL: An Open-Source Software for Earthquake Risk, Loss and Lifecycle Assessment

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Evaluating earthquake-induced losses, such as structural repair costs, downtime and casualties, is becoming a standard practice within the performance-based earthquake engineering framework. Nonetheless, this evaluation is a demanding task that requires de ...

2021

Proposed Panel Zone Model for Seismic Design of Steel Moment-Resisting Frames

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady, Andronikos Skiadopoulos

This paper proposes a new mechanics-based model for the seismic design of beam-to-column panel zone joints in steel moment-resisting frames. The model is based on realistic shear stress distributions retrieved from continuum finite element (CFE) analyses o ...

ASCE-AMER SOC CIVIL ENGINEERS2021

Experimental Evaluation and Numerical Modeling of Wide-Flange Steel Columns Subjected to Constant and Variable Axial Load Coupled with Lateral Drift Demands

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper presents results from an experimental evaluation on the pre- and post-buckling behavior of 12 steel wide-flange cantilever columns under axial load and lateral drift demands. The influence of several loading and geometric parameters, including t ...

2020

Proposed methodology for building-specific earthquake loss assessment including column residual axial shortening

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper proposes methodological developments for quantifying the impact of residual axial shortening of first-story steel columns on earthquake loss estimations in steel moment-resisting frame (MRF) buildings. A new formulation is proposed that accounts ...

2020

EaRL—Software for Earthquake Risk, Loss and Lifecycle Analysis

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Performance-based earthquake engineering (PBEE) has become an increasingly popular framework to design, retrofit and manage structures. This probabilistic framework integrates data from the seismic hazard, structural response, damage fragility and damage c ...

2020

Hysteretic Behavior of Moment-Resisting Frames Considering Slab Restraint and Framing Action

Dimitrios Lignos, Hammad El Jisr, Ahmed Mohamed Ahmed Elkady

This paper examines the influence of framing action and slab continuity on the hysteretic behavior of composite steel moment-resisting frames (MRFs) by means of high-fidelity continuum finite-element (CFE) analyses of two-bay subsystems and typical crucifo ...

2020

Composite steel beam database for seismic design and performance assessment of composite-steel moment-resisting frame systems

Dimitrios Lignos, Hammad El Jisr, Ahmed Mohamed Ahmed Elkady

This paper discusses the development of a publicly available database of composite steel beam-to-column connections under cyclic loading. The database is utilized to develop recommendations for the seismic design and nonlinear performance assessment of ste ...

2019

Proposed Updates to the ASCE 41 Nonlinear Modeling Parameters for Wide-Flange Steel Columns in Support of Performance-Based Seismic Engineering

Dimitrios Lignos, Alexander Riley Hartloper, Ahmed Mohamed Ahmed Elkady

Nonlinear static and dynamic analyses are utilized by engineers for performance-based seismic risk evaluation of new and existing structures. In this context, nonlinear component modeling criteria are typically based on ASCE 41 guidelines. Experiments on w ...

2019

Improved Seismic Design and Nonlinear Modeling Recommendations for Wide-Flange Steel Columns

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper presents the findings of parametric finite-element (FE) simulations of more than 50 wide-flange steel columns under cyclic loading. The column sizes, which are mostly highly ductile according to the current design practice in North America, are ...

2018

Revised ASCE-41 modeling recommendations for moment-resisting frame systems

Dimitrios Lignos, Alexander Riley Hartloper, Ahmed Mohamed Ahmed Elkady

Nonlinear static and dynamic analysis is utilized by engineers to evaluate the seismic behavior of new and existing structures in the context of performance-based earthquake engineering. Numerous experiments on steel moment-resisting frames and their compo ...

2018

EaRL: Toolbox for Earthquake Risk and Loss Assessment of Building Assets

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady, Seong-Hoon Hwang

Infrastructure (asset) risk management is essential for a resilient environment. Several industries are concerned to improve their building asset preparedness subject to seismic hazard. To this end, the development of software tools that quantify and asses ...

2018

Fragility Curves for Wide-Flange Steel Columns and Implications on Building-Specific Earthquake-Induced Loss Assessment

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady, Subash Ghimire

Building-specific loss assessment methodologies utilize component fragility curves to compute the expected losses in the aftermath of earthquakes. Such curves are not available for steel columns assuming they remain elastic due to capacity design considera ...

2018

Full-Scale Testing of Deep Wide-Flange Steel Columns under Multiaxis Cyclic Loading: Loading Sequence, Boundary Effects, and Lateral Stability Bracing Force Demands

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper discusses the findings from 10 full-scale steel column tests subjected to multiaxis cyclic loading. The columns use deep wide-flange cross sections typically seen in steel moment-resisting frames designed in seismic regions. The effects of bound ...

2018

Steel Columns under Multi-Axis Seismic Loading: Experimental Findings and Design Recommendations

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

This paper summarizes the findings of two test programs that investigated the hysteretic behavior of wide-flange columns in steel moment-resisting frames. Both deep and shallow steel columns were examined. The members were subjected to unidirectional and b ...

Trans Tech Publications2018

Development of Bidirectional Cyclic Lateral Loading Protocols for Experimental Testing of Steel Wide-Flange Columns

Dimitrios Lignos, Ahmed Mohamed Ahmed Elkady

Steel columns in frame buildings subjected to earthquake shaking undergo bidirectional lateral drift demands. Till now, the majority of past experimental and numerical studies were primarily concerned with the unidirectional column behavior. This paper pro ...

2017

Experimental and Numerical Evaluation of Steel Columns for Performance-Based Seismic Assessment of Steel Moment Frames

Dimitrios Lignos, Alexander Riley Hartloper, Ahmed Mohamed Ahmed Elkady

This paper summarizes the findings of a long term experimental program corroborated with detailed finite element simulations that investigated the hysteretic behavior of wide-flange columns in steel moment-resisting frames (MRFs) designed in highly seismic ...

2017