Publications associées à Experimental Investigation of Instability-Free Welded Moment Connections With Simplified Weld Details

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

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

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

Experimental and analytical investigation of shear-reinforced concrete and dowel action

Marko Pejatovic

Codes of practice can be overly conservative, particularly for the shear resistance of reinforced concrete beams with shear reinforcement when large loads act close to supports. This thesis addresses the topic by proposing a refined design approach based o ...

EPFL2024

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

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

Hysteretic behaviour of welded connections with highly inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos

The current practice in capacity-designed steel moment resisting frames (MRFs) worldwide allows for limitedshear yielding in the column web panel zone. As such, inelastic deformations concentrate near the beam ends, thereby leading to flexural stre ...

Ernst & Sohn2023

Exploring the potential of the critical shear crack theory for reinforced and post-tensioned glass beams: Initial analysis and experiments

Alain Nussbaumer, Pieter Christian Louter, Jagoda Cupac

In the evolution of structural glass beam elements, the requirements for post-fracture load bearing capacity and safe failure behaviour have led to the development of reinforced and post-tensioned beams. Maximum bending capacity in the post-fracture state ...

2023

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

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

Dissipative Embedded Column Bases for Enhanced Seismic Performance of Steel Moment Resisting Frames

Albano António De Abreu E Presa De Castro E Sousa, Dimitrios Lignos, Hiroyuki Inamasu

This paper presents an innovative design concept for embedded column base (ECB) connections. The developed ECB connection achieves a non-degrading hysteretic response. In the proposed ECB connections, the dissipative zone is shifted into the embedded porti ...

EEME2023

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

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

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

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

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

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

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

Full-scale testing of European steel beams with reduced beam section under reversed cyclic loading

Dimitrios Lignos, Hiroyuki Inamasu

Steel beams with reduced beam section (RBS) are often used as part of prequalified connections in seismic regions. However, RBS connections are not as common in Europe. Reasons relate to easiness in fabrication, which requires on-site welding, and the seis ...

Springer Nature2022

Seismic stability of steel moment resisting frames with inelastic panel zones

Dimitrios Lignos, Andronikos Skiadopoulos

This paper summarizes preliminary findings of nonlinear simulations aiming to quantify the seismic demands of codecompliant steel MRFs with variable panel zone targeted shear distortions, 𝛾!. The probability of beam fractures is explicitly considered in th ...

Earthquake Engineering Research Institute2022