Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleDai R, Behzadi-Sofiani B, Buhagiar S, et al., 2024,
Behaviour, finite element modelling and design of flanged cruciform section steel columns
, Thin Walled Structures, Vol: 204, ISSN: 0263-8231A study into the mechanical behaviour and design of flanged cruciform section steel members subjected to axial compression is presented herein. The mechanical behaviour of flanged cruciform section columns is first described, with particular emphasis on the newly developed approach for determining the elastic local buckling load for full flanged cruciform cross-sections. Existing experimental data on flanged cruciform section steel columns collected from the literature are then employed to validate numerical models developed within the finite element package ABAQUS. A comprehensive parametric study is subsequently conducted that encompasses a broad spectrum of cross-sectional geometries and global slenderness values. The mechanical behaviour and ultimate resistance of flanged cruciform section columns are shown to be dependent on not only the global slenderness, but also on the ratio of the elastic torsional to flexural buckling loads. The existing experimental data alongside the numerical parametric study results are employed to evaluate the resistance predictions provided in the current Eurocode 3 design codes, revealing a high degree of conservatism. Finally, a new design approach for flanged cruciform section columns, suitable for incorporation into future revisions of Eurocode 3, is proposed which provides significantly improved accuracy and consistency in resistance predictions compared with the current provisions. A reliability analysis of the proposed design approach is conducted in accordance with the EN 1990 procedure, resulting in a recommended partial safety factor 𝛾M₁ = 1.0.
-
Journal articleVicencio F, Torres-Olivares S, Miranda-Garnica M, et al., 2024,
Seismic assessment of SSSI effects between adjacent Cross-Laminated Timber (CLT) buildings
, STRUCTURES, Vol: 69, ISSN: 2352-0124 -
Journal articleZhang Y, MálagaChuquitaype C, Lavan O, 2024,
Mixed Lagrangian formulation for modeling structures with clutched inerter devices
, Earthquake Engineering and Structural Dynamics, Vol: 53, Pages: 4203-4222, ISSN: 0098-8847Inerters (ID) and Clutched Inerter Devices (CID) are a novel technology with demonstrated seismic control potential. However, the inherent nonlinearity and discontinuity of the clutching phenomena in CIDs can pose significant challenges for their accurate numerical modeling. In general, conventional existing methods either oversimplify the physics involved or are sensitive to the step size and thus are inherently unstable, demanding excessive numerical resources. Most relevant studies to date have focused on small-scale systems with a limited number of inerters and have used simplified models due to the lack of analysis tools. At the same time, the Mixed Lagrangian Formulation (MLF), has proven to be a powerful tool for simulating non-smooth dynamics phenomena. This paper presents an alternative way of modeling the behavior of CIDs in both MLF and conventional finite element method. We put forward an original formulation of the inerter element, clutching behavior, and the inerter-related dissipation model, as well as their associated computational scheme in MLF and the equivalent construction in FEM. The newly proposed CID element in MLF is then implemented and validated through three examples, including a single degree of freedom system, a multi 10-storey moment resisting frame (MRF), and a 10-storey self-centering concentrically braced frame (SC-CBF) with multiple rocking sections. The results are compared to those from existing models used for clutching inerter and to the proposed FE model. Finally, the advantages of using the MLF framework and salient characteristics of the structures equipped with clutched inerters are discussed. The modeling strategy proposed in this work empowers researchers to simulate structures with a larger number of degrees of freedom, equipped with a considerable amount of inerter-based devices, with reduced effort and improved computational performance.
-
Journal articleYang J, Kyvelou P, Wadee MA, et al., 2024,
Simulation and prediction of residual stresses in WAAM-strengthened I-sections
, Structures, Vol: 69, ISSN: 2352-0124The use of wire arc additive manufacturing (WAAM) as a means of strengthening conventional steelwork is an emerging area of research. An experimental study has revealed that the residual stress distribution in WAAM-strengthened (at the flange tips) I-sections differs significantly from that of a typical hot-rolled I-section, owing to the thermal prestressing arising during WAAM; thus, the establishment of a bespoke residual stress model for WAAM-strengthened I-sections is required. In this paper, 3D thermal-mechanical finite element (FE) modelling is employed to predict the residual stress distributions in WAAM-strengthened I-sections, using two modelling methods – a 3D-transient method and a simplified semi-static method; both modelling methods are shown to provide an accurate representation of experimental observations, with the latter being more computational efficient. Further improvementsin computational efficiency, with almost no compromise in accuracy, are achieved through the introduction of a hybrid numerical-analytical approach. The proposed approach uses the simplified semi-static method to simulate the first WAAM layer only and an analytical modification to allow for multi-layer WAAM stiffeners. Using the hybrid approach, a parametric study is performed in which numerical simulations on a total of 524 benchmark members with varying geometric properties covering a wide range of UK and European I-sections are carried out. Based on the obtained results, predictive expressions for the residual stress distributions in WAAM-strengthened I-sections are developed; the predicted residual stress patterns are shown to be in good agreement with both experimental and numerical results. Use of these expressions is recommended to determine the pattern and magnitude of residual stresses in WAAM-strengthened I-sections for the purposes of numerical simulations and the development of structural design provisions.
-
Journal articleBehzadi-Sofiani B, Wadee MA, Gardner L, 2024,
Pin-ended stainless steel equal-leg angle section members under compression and major-axis bending: experimentation, FE modelling and design
, Thin Walled Structures, Vol: 203, ISSN: 0263-8231The behaviour and design of cylindrically-pinned stainless steel equal-leg angle section members under compression and compression combined with strong-axis bending are investigated herein. An experimental investigation, including material testing, initial geometric imperfection measurements and physical tests on hot-rolled stainless steel equal-leg angle section members is first presented. Numerical models are developed by means of shell finite element modelling formulated within ABAQUS and validated against experimental data. A numerical parametric study is then presented considering both hot-rolled and cold-formed stainless steel equal-leg angle section columns alongside beam-columns with a wide range of cross-section and member geometries. Finally, new design proposals for cylindrically-pinned stainless steel equal-leg angle section members under compression and compression plus major-axis bending are developed and verified against the results of physical experiments and numerical simulations. The proposed design rules are shown to offer substantially more accurate and consistent resistance predictions compared to existing codified design rules. The reliability of the new design provisions, with a recommended partial safety factor γM1 = 1.1, is verified following the EN 1990 procedure.
-
Journal articleQuishpe-Otacoma C, Tello-Ayala K, Malaga-Chuquitaype C, et al., 2024,
Experimental and numerical cyclic response of mixed steel-concrete shear walls
, FRONTIERS IN BUILT ENVIRONMENT, Vol: 10 -
Journal articlePanto' B, Ortega J, Grosman S, et al., 2024,
Advanced calibration of a 3D masonry arch bridge model using non-destructive testing and numerical optimisation
, Construction and Building Materials, Vol: 438, ISSN: 0950-0618Historical masonry arch bridges constitute the backbone of many existing transportation networks in different countries in Europe and worldwide. They represent valuable cultural heritage assets and play an essential social and economic role. Since construction, old masonry bridges have accumulated structural damage from traffic and environmental actions. Furthermore, depending on their geometrical and mechanical characteristics, they may be particularly vulnerable to extreme events like earthquakes. Thus, accurate structural assessment under different loading conditions is critical for the conservation of these structures. Realistic assessment requires suitable numerical models to represent the characteristic 3D behaviour. The complexity of this task is further compounded by the practical difficulty in obtaining essential information on the internal bridge structure and the masonry mechanical parameters, which are vital to achieve accurate response predictions against service and extreme actions.This paper presents an advanced calibration procedure for a refined macroscale bridge model, allowing for the anisotropic nature of the masonry material. The proposed calibration approach is applied to an actual multi-span masonry viaduct, where sonic, ultrasonic, and ground penetrating radar tests are conducted to investigate the internal structure of the viaduct and determine the elastic properties of the masonry materials. In addition, the dynamic characteristics of the bridge are evaluated through in-situ measurements under environmental vibrations and used for model validation. The results from a standard simplified model calibration and an enhanced calibration are compared considering the vibration modes of the bridge. Simplified calibration is carried out using the results from in-situ tests, while a statistic inference procedure and numerical optimisation are adopted in the refined calibration to achieve improved accuracy. Although the paper focuses on a specific cas
-
Conference paperEl Khoury K, Vollum R, Izzuddin B, 2024,
Restraint-Induced Cracking in Edge-Restrained Walls: Validation of Numerical Model and Parametric Study
, 15th fib PhD Symposium Budapest -
Journal articleSlack H, Walport F, Chan HU, et al., 2024,
A consistent approach to the definition of initial geometric imperfections for in-plane stability design of steel moment frames
, Structures, Vol: 65, ISSN: 2352-0124Geometric imperfections can have a significant influence on the behaviour and ultimate resistance of steel structures. For the purposes of structural design, particularly design by geometrically and materially nonlinear analysis with imperfections (GMNIA), a suitable choice of imperfections, in terms of both amplitude and shape, is therefore required; an inappropriate choice of imperfections can lead to misleading results and unsafe resistance predictions. The development of a practical strategy for defining imperfection shapes in the in-plane GMNIA-based design of steel moment frames is the focus of the present study. The proposals are also suitable for GNIA-based design. Both overall sway imperfections (i.e. frame out-of-plumbness) and individual member bow imperfections, together with combinations thereof (i.e. sway-member imperfection combinations), are considered. Several methods for introducing imperfections are assessed. Each method is categorised depending upon whether the imperfection is established through: (1) direct definition or (2) the scaling of eigenmodes. The recommended direct definition-based method introduces a sway imperfection in sympathy with the applied lateral loading and member imperfections with alternating directions between storeys, as dictated by the column base boundary conditions. The recommended eigenmode-based method uses the first sway mode and determines the number of non-sway modes according to the eigenvalues under the design loading, with all non-sway modes for which the eigenvalues αcr,ns < 25 also contributing to the imperfection. The eigenmodes are scaled to ensure the bounds of the prescribed imperfection amplitudes are suitably maintained. The consistency and accuracy of the proposed methods are demonstrated for 21 different frame configurations.
-
Journal articleLapira L, Gardner L, Wadee MA, 2024,
A new model for calculating the ultimate shear resistance of steel I-section girders
, Thin Walled Structures, Vol: 200, ISSN: 0263-8231The design resistance in shear of thin-walled I-sections has elicited numerous theories over the past decades. While there is a consensus on the post-buckling tension-field action that increases the ultimate resistance of thin webs in shear, the mechanism governing this tension-field action still remains debated. Presently, four constituent components for the shear resistance of I-sections are identified: (1) the resistance of the isolated web subject to a pure shear stress; (2) an increase in the web buckling stress due to flexural restraints provided by the flanges; (3) an increased web post-buckling resistance due to membrane restraint provided by the flanges; and (4) a direct contribution from the flanges to the shear resistance of the I-section. Each of these components is examined through parametric studies using finite element (FE) models analysed within Abaqus that are validated against published experimental results. A new design methodology for the resistance of I-sections in shear is presented, with closed-form expressions developed for each of the four component contributions. When compared with the current approach within EN 1993-1-5, the proposed formulae predict the shear resistance of the cross-section with greater accuracy and consistency.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.