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

A Softening Constitutive Law and Gradient-Inelastic Fiber-Based Element for 3-Dimensional Frame Simulations Under Seismic Excitations

Steel frame structures are essential components of modern infrastructure. Understanding their behavior under seismic loading is critical for ensuring public safety and minimizing damage that occurs during earthquakes. To accurately predict the response of ...

EPFL2024

Reducing uncertainties in response predictions of earthquake-damaged masonry buildings using data from image-based inspection

Ian Smith, Katrin Beyer, Bryan German Pantoja Rosero, Mathias Christian Haindl Carvallo

Image information about the state of a building after an earthquake, which can be collected without endangering the post-earthquake reconnaissance activities, can be used to reduce uncertainties in response predictions for future seismic events. This paper ...

Springer2024

Numerical Modeling of FRP-Strengthened Masonry Structures Using Equivalent Frame Models

Katrin Beyer, Francesco Vanin, Ivana Bozulic

The present study focuses on enhancing the seismic resistance of existing masonry structures. To that aim, the use of fiber-reinforced polymer (FRP) strengthening serves to improve structural behaviour by attaching FRP strips to the masonry walls. Despite ...

Springer2024

Fault roughness controls injection-induced seismicity

Lei Wang, Simon Guérin-Marthe

Surface roughness ubiquitously prevails in natural faults across various length scales. Despite extensive studies highlighting the important role of fault geometry in the dynamics of tectonic earthquakes, whether and how fault roughness affects fluid-induc ...

National Academy of Sciences2024

Frictional weakening leads to unconventional singularities during dynamic rupture propagation

Marie Estelle Solange Violay, François Xavier Thibault Passelègue, Federica Paglialunga, Mathias Alexandre David Lebihain

Earthquakes i.e. frictional ruptures, are commonly described by singular solutions of shear crack motions. These solutions assume a square root singularity order around the rupture tip and a constant shear stress value behind it, implying scale-independent ...

2024

Seismic Testing of Adjacent Interacting Masonry Structures – Analysis of a Blind Prediction

Katrin Beyer, Andrea Penna, Igor Tomic

Masonry aggregates, which emerged as layouts of cities and villages became denser, make up historical centres all over the world. In these aggregates, neighbouring structures may share structural walls that are joined at the interfaces by mortar or interlo ...

Springer2024

Experimental Investigation on Size-Effect of Rubble Stone Masonry Walls Under In-Plane Horizontal Loading: Overview and Preliminary Results

Katrin Beyer, Savvas Saloustros

Rubble stone masonry is a common construction typology of historical city centres and vernacular architecture. While past earthquakes have shown that it is one of the most vulnerable masonry construction typologies, there are few experimental campaigns giv ...

2024

Shear and steel-fibre reinforcement for the punching resistance of flat slabs at internal and edge columns

Diego Hernández Fraile

Reinforced concrete flat slabs consist of a continuous, thin concrete plate that rests on a grid of columns. The supporting surface of the columns is very small compared to the floor plan dimensions, leading to concentrations of shear forces near the colum ...

EPFL2024

Influence of model uncertainty and long term deformations in action effects calculation in reinforced concrete structures

Xhemsi Malja

Most codes of practice adopt a semi probabilistic design approach for the dimensioning and assessment of structures. Accordingly, structural safety is ensured by performing limit state verifications using design values determined with adequately calibrated ...

EPFL2024

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

Energy dissipation in fiber-polymer composites adhesive joints under cyclic loading

Ghazaleh Eslami

Sustainable development has emerged as a paramount consideration in various fields of industry, including construction, to preserve the environment and its finite resources. Lightweight structures, such as fiber-polymer composite structures, address both s ...

EPFL2023

Full Scale Experiments of a Composite Steel Moment Resisting Frame: Behavioral Insights and Implications on Seismic Design

Dimitrios Lignos, Hammad El Jisr

This paper discusses the cyclic performance of a heavily instrumented 2-bay full-scale composite-steel moment resisting frame (CMRF) sub-system from the onset of structural damage up until incipient collapse. The CMRF featured stiffened end plate bolted co ...

EEME2023

Full-Scale Experiments of Cyclically Loaded Welded Moment Connections with Highly Dissipative Panel Zones and Simplified Weld Details

Dimitrios Lignos, Andronikos Skiadopoulos

This paper presents the experimental results of two welded unreinforced flange-welded web (WUF-W) beam-to-column connections that defy the current design paradigm of prequalified welded connections. The proposed WUF-W connections feature customized beveled ...

2023

The new Chapter 9 of Eurocode 8 Part 3 for Seismic Assessment of Existing Steel Structures

Dimitrios Lignos

The seismic assessment of existing steel structures necessitates the development of practice- oriented engineering models for use in nonlinear static and dynamic analysis procedures. These models should encompass the full range of the anticipated nonlinear ...

2023

Seismic Assessment and Retrofit of Pre-Northridge High Rise Steel Moment Resisting Frame Buildings with Bilinear Oil Dampers

Dimitrios Lignos

This paper presents quantitative information on the effectiveness of seismic retrofit solutions using bilinear oil dampers for seismically deficient existing tall steel buildings. For this purpose, a benchmark 40-story steel space moment-resisting frame bu ...

MDPI2023

Surrogate modelling for seismic collapse risk assessment of steel moment resisting frames

Dimitrios Lignos, Andronikos Skiadopoulos, Nenad Bijelic

With the overall goal of reducing the numerical burden of uncertainty quantification involved in seismic risk assessments, this paper examines opportunities for assessment of seismic collapse capacity and risk using data-driven surrogates as a complement t ...

2023

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

Equivalent Frame Models for FRP-Strengthened Masonry Buildings

Fibre-reinforced polymers (FRP) strengthening can be applied to decrease the seismic vulnerability of existing masonry buildings, both with regard to in-plane and out-of-plane failure mechanisms. Experimentally, the impact of strengthening solutions has be ...

Proceedings of the 2nd Croatian Conference on Earthquake Eng2023

Geometric tolerances of welded connections with inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos, Ce Wen

Prequalified beam-to-column connections in steel moment resisting frames usually concentrate inelastic deformations in the steel beam ends. As such, nonlinear geo-metric instabilities (i.e., local buckling) may occur in these regions at modest lateral drif ...

Ernst & Sohn2023

Towards instability-free welded moment connections

Dimitrios Lignos, Andronikos Skiadopoulos

In capacity-designed steel moment resisting frames (MRFs), inelastic deformations are mostly concentrated in the steel beams and the column fixed ends of the first story, while the participation of the panel zones in energy dissipation is limited. In such ...

2023