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Dimitrios Lignos

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Publications associées (155)

Behaviour of stiffened extended shear tab connections under gravity induced shear force

Dimitrios Lignos

Stiffened extended shear tab connections (either in full-depth or partial-depth configurations) are widely used to connect simply supported beams to the web of supporting girders or columns. Full-scale laboratory tests of stiffened extended shear tab conne ...

2018

Composite beam effects and implications to seismic design provisions

Dimitrios Lignos, Hammad El Jisr

Previous studies have investigated the slab effects on the cyclic behavior of composite beams in moment-resisting frames. Of interest in this paper, is the slab contribution to the flexural strength and effective stiffness of the beam. The former influence ...

2018

Earthquake-Induced Collapse Risk and Loss Assessment of Steel Concentrically Braced Frames

Dimitrios Lignos, Seong-Hoon Hwang

This paper quantifies the collapse risk and earthquake-induced losses for a wide range of archetype buildings with special concentrically braced frames (SCBFs). The collapse risk and expected economic losses associated with repair, demolition and collapse ...

2018

Nonmodel-based framework for rapid seismic risk and loss assessment of instrumented steel buildings

Dimitrios Lignos, Seong-Hoon Hwang

This paper proposes a nonmodel-based framework for estimating story-based engineering demand parameters (EDPs) in instrumented steel frame buildings with steel moment-resisting frames (MRFs). The proposed framework utilizes a wavelet-based damage-sensitive ...

Elsevier2018

Adaptive numerical method algorithms for nonlinear viscous and bilinear oil damper models subjected to dynamic loading

Dimitrios Lignos

Adaptive numerical method algorithms are presented for the numerical simulation of the hysteretic behaviour of nonlinear viscous and bilinear oil dampers within a finite element program for nonlinear dynamic analysis of frame structures under earthquake ex ...

2018

Simulating Local Buckling-Induced Softening in Steel Members Using an Equivalent Nonlocal Material Model in Displacement-Based Fiber Elements

Dimitrios Lignos

Fiber-based elements are commonly used to simulate steel beam-columns because of their ability to capture P-M interactions and spread of plasticity. However, when mechanisms such as local buckling result in effective softening at the fiber scale, conventio ...

2018

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

Fatigue Strength Upgrading of Cover Plate Ends by Welded Extensions in Existing Steel Bridge Girders

Alain Nussbaumer, Vasileios Grigoriou, Dimitrios Lignos

This paper investigates the fatigue upgrading of typical cover plate joint connections in existing steel bridge girders through cover plate extension. The upgraded detail is created by removing the existing transverse end weld, then welding the extension t ...

2018

Fiber-based model for earthquake-induced collapse simulation of steel frame buildings

Dimitrios Lignos

Earthquake-induced collapse risk assessment of steel frame buildings requires the use of simulation models that can realistically replicate dynamic instability of frame buildings. Such models for steel columns should consider the coupling between the axial ...

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

Earthquake-Induced Collapse Risk and Loss Assessment of Steel Concentrically Braced Frames

Dimitrios Lignos, Seong-Hoon Hwang

2018

Influence of embedded steel column base strength on earthquake-induced residual deformations

Dimitrios Lignos, Hiroyuki Inamasu

Recent experiments on steel columns under multi-axis cyclic loading suggest that a steel column may experience appreciable axial shortening due to local buckling. Reconnaissance reports from recent earthquakes indicate that a number of embedded column base ...

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

Improving the collapse risk of steel structures with high-performance steel

Dimitrios Lignos

With the advent of material science, high-performance steel materials have been developed for seismic applications that potentially reduce the earthquake-induced collapse risk of steel frame buildings. The High Yield Point (HYP400) steel is one of those ma ...

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

Influence of non-structural components on the seismic response of cold-formed steel structures

Dimitrios Lignos

Shortcomings exist with respect to accounting for the influence of non-structural components, e.g. gypsum panels installed on the ceilings (floors and roof diaphragms) and walls, on the response of cold-formed steel (CFS) framed structures subjected to sei ...

2018

Seismic retrofit of steel tall buildings with bilinear oil dampers

Dimitrios Lignos

This paper presents retrofit solutions for existing tall buildings by utilizing supplemental damping devices, namely oil dampers with relief valve (bilinear oil dampers). To this end, multiple retrofit schemes are presented for a benchmark 40-story steel m ...

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

Seismic Performance Characterization of Wood-Sheathed and Cold-Formed Steel Framed Floor and Roof Diaphragm Structures

Dimitrios Lignos

This paper describes a research program involving wood-sheathed and cold-formed steel (CFS) framed diaphragm assemblies.The diaphragm’s response to in-plane monotonic and reversed cyclic lateral loading is investigated in an effort to characterize the seis ...

Asce-Amer Soc Civil Engineers2018

Assessment of structural damage detection methods for steel structures using full-scale experimental data and nonlinear analysis

Dimitrios Lignos, Seong-Hoon Hwang

Rapid structural damage assessment methodologies are essential to properly allocate emergency response and minimize business interruption due to downtime in the aftermath of earthquakes. Within this context, data-driven algorithms supported by sensing capa ...

2018

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