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Dr. Vagelis Plevris
Qatar University

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Research Keywords & Expertise

0 Concrete
0 Earthquake Engineering
0 FEM
0 FEM analysis
0 Neural Networks

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Concrete
Neural Networks
Robust Design
particle swarm optimization (PSO)
Reliability Analysis
Optimization methods
Finite Element Analysis (FEA)

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Short Biography

Dr. Vagelis Plevris is an Associate Professor at the Department of Civil & Architectural Engineering of Qatar University in Doha, Qatar. He serves as Chief Editor for "Computational Methods in Structural Engineering", a section of the journal Frontiers in Built Environment, by Frontiers in Switzerland.

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Journal article
Published: 29 May 2021 in Applied Sciences
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A new, fast, elegant, and simple stochastic optimization search method is proposed, which exhibits surprisingly good performance and robustness considering its simplicity. We name the algorithm pure random orthogonal search (PROS). The method does not use any assumptions, does not have any parameters to adjust, and uses basic calculations to evolve a single candidate solution. The idea is that a single decision variable is randomly changed at every iteration and the candidate solution is updated only when an improvement is observed; therefore, moving orthogonally towards the optimal solution. Due to its simplicity, PROS can be easily implemented with basic programming skills and any non-expert in optimization can use it to solve problems and start exploring the fascinating optimization world. In the present work, PROS is explained in detail and is used to optimize 12 multi-dimensional test functions with various levels of complexity. The performance is compared with the pure random search strategy and other three well-established algorithms: genetic algorithms (GA), particle swarm optimization (PSO), and differential evolution (DE). The results indicate that, despite its simplicity, the proposed PROS method exhibits very good performance with fast convergence rates and quick execution time. The method can serve as a simple alternative to established and more complex optimizers. Additionally, it could also be used as a benchmark for other metaheuristic optimization algorithms as one of the simplest, yet powerful, optimizers. The algorithm is provided with its full source code in MATLAB for anybody interested to use, test or explore.

ACS Style

Vagelis Plevris; Nikolaos Bakas; German Solorzano. Pure Random Orthogonal Search (PROS): A Plain and Elegant Parameterless Algorithm for Global Optimization. Applied Sciences 2021, 11, 5053 .

AMA Style

Vagelis Plevris, Nikolaos Bakas, German Solorzano. Pure Random Orthogonal Search (PROS): A Plain and Elegant Parameterless Algorithm for Global Optimization. Applied Sciences. 2021; 11 (11):5053.

Chicago/Turabian Style

Vagelis Plevris; Nikolaos Bakas; German Solorzano. 2021. "Pure Random Orthogonal Search (PROS): A Plain and Elegant Parameterless Algorithm for Global Optimization." Applied Sciences 11, no. 11: 5053.

Original paper
Published: 26 April 2021 in Stochastic Environmental Research and Risk Assessment
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Optimization algorithms appear in the core calculations of numerous Artificial Intelligence (AI) and Machine Learning methods and Engineering and Business applications. Following recent works on AI’s theoretical deficiencies, a rigour context for the optimization problem of a black-box objective function is developed. The algorithm stems directly from the theory of probability, instead of presumed inspiration. Thus the convergence properties of the proposed methodology are inherently stable. In particular, the proposed optimizer utilizes an algorithmic implementation of the n-dimensional inverse transform sampling as a search strategy. No control parameters are required to be tuned, and the trade-off among exploration and exploitation is, by definition, satisfied. A theoretical proof is provided, concluding that when falling into the proposed framework, either directly or incidentally, any optimization algorithm converges. The numerical experiments verify the theoretical results on the efficacy of the algorithm apropos reaching the sought optimum.

ACS Style

Nikolaos P. Bakas; Vagelis Plevris; Andreas Langousis; Savvas A. Chatzichristofis. ITSO: a novel inverse transform sampling-based optimization algorithm for stochastic search. Stochastic Environmental Research and Risk Assessment 2021, 1 -10.

AMA Style

Nikolaos P. Bakas, Vagelis Plevris, Andreas Langousis, Savvas A. Chatzichristofis. ITSO: a novel inverse transform sampling-based optimization algorithm for stochastic search. Stochastic Environmental Research and Risk Assessment. 2021; ():1-10.

Chicago/Turabian Style

Nikolaos P. Bakas; Vagelis Plevris; Andreas Langousis; Savvas A. Chatzichristofis. 2021. "ITSO: a novel inverse transform sampling-based optimization algorithm for stochastic search." Stochastic Environmental Research and Risk Assessment , no. : 1-10.

Journal article
Published: 07 February 2021 in Modelling
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In this work, the performance of reliability methods for the probabilistic analysis of local scour at a bridge pier is investigated. The reliability of bridge pier scour is one of the important issues for the risk assessment and safety evaluation of bridges. Typically, the depth prediction of bridge pier scour is estimated using deterministic equations, which do not consider the uncertainties related to scour parameters. To consider these uncertainties, a reliability analysis of bridge pier scour is required. In the recent years, a number of efficient reliability methods have been proposed for the reliability-based assessment of engineering problems based on simulation, such as Monte Carlo simulation (MCS), subset simulation (SS), importance sampling (IS), directional simulation (DS), and line sampling (LS). However, no general guideline recommending the most appropriate reliability method for the safety assessment of bridge pier scour has yet been proposed. For this purpose, we carried out a comparative study of the five efficient reliability methods so as to originate general guidelines for the probabilistic assessment of bridge pier scour. In addition, a sensitivity analysis was also carried out to find the effect of individual random variables on the reliability of bridge pier scour.

ACS Style

Jafar Jafari-Asl; Mohamed Ben Seghier; Sima Ohadi; You Dong; Vagelis Plevris. A Comparative Study on the Efficiency of Reliability Methods for the Probabilistic Analysis of Local Scour at a Bridge Pier in Clay-Sand-Mixed Sediments. Modelling 2021, 2, 63 -77.

AMA Style

Jafar Jafari-Asl, Mohamed Ben Seghier, Sima Ohadi, You Dong, Vagelis Plevris. A Comparative Study on the Efficiency of Reliability Methods for the Probabilistic Analysis of Local Scour at a Bridge Pier in Clay-Sand-Mixed Sediments. Modelling. 2021; 2 (1):63-77.

Chicago/Turabian Style

Jafar Jafari-Asl; Mohamed Ben Seghier; Sima Ohadi; You Dong; Vagelis Plevris. 2021. "A Comparative Study on the Efficiency of Reliability Methods for the Probabilistic Analysis of Local Scour at a Bridge Pier in Clay-Sand-Mixed Sediments." Modelling 2, no. 1: 63-77.

Journal article
Published: 14 September 2020 in Crystals
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Recently, the use of fiber-reinforced polymers (FRP)-confinement has increased due to its various favorable effects on concrete structures, such as an increase in strength and ductility. Therefore, researchers have been attracted to exploring the behavior and efficiency of FRP-confinement for concrete structural elements further. The current study investigates improved strength and strain models for FRP confined concrete cylindrical elements. Two new physical methods are proposed for use on a large preliminary evaluated database of 708 specimens for strength and 572 specimens for strain from previous experiments. The first approach is employing artificial neural networks (ANNs), and the second is using the general regression analysis technique for both axial strength and strain of FRP-confined concrete. The accuracy of the newly proposed strain models is quite satisfactory in comparison with previous experimental results. Moreover, the predictions of the proposed ANN models are better than the predictions of previously proposed models based on various statistical indices, such as the correlation coefficient (R) and mean square error (MSE), and can be used to assess the members at the ultimate limit state.

ACS Style

Afaq Ahmad; Vagelis Plevris; Qaiser-Uz-Zaman Khan. Prediction of Properties of FRP-Confined Concrete Cylinders Based on Artificial Neural Networks. Crystals 2020, 10, 811 .

AMA Style

Afaq Ahmad, Vagelis Plevris, Qaiser-Uz-Zaman Khan. Prediction of Properties of FRP-Confined Concrete Cylinders Based on Artificial Neural Networks. Crystals. 2020; 10 (9):811.

Chicago/Turabian Style

Afaq Ahmad; Vagelis Plevris; Qaiser-Uz-Zaman Khan. 2020. "Prediction of Properties of FRP-Confined Concrete Cylinders Based on Artificial Neural Networks." Crystals 10, no. 9: 811.

Review
Published: 13 August 2020 in Forests
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The conservation of heritage structures is pivotal not only due to their cultural or historical importance for nations, but also for understanding their construction techniques as a lesson that can be applied to contemporary structures. Timber is considered to be the oldest organic construction material and is more vulnerable to environmental threats than nonorganic materials such as masonry bricks. In order to assess the structural vulnerability of heritage timber structures subjected to different types of risk, knowledge about their structural systems and configurations, the nature and properties of the materials, and the behavior of the structure when subjected to different risks, is essential for analysts. In order to facilitate the procedure, different assessment methods have been divided into the categories in situ and ex situ, which are applicable for vulnerability assessments at the element and full-scale level of a case study. An existing methodology for structural vulnerability assessments and conservation of heritage timber buildings is reviewed and a new methodology is proposed.

ACS Style

Amirhosein Shabani; Mahdi Kioumarsi; Vagelis Plevris; Haris Stamatopoulos. Structural Vulnerability Assessment of Heritage Timber Buildings: A Methodological Proposal. Forests 2020, 11, 881 .

AMA Style

Amirhosein Shabani, Mahdi Kioumarsi, Vagelis Plevris, Haris Stamatopoulos. Structural Vulnerability Assessment of Heritage Timber Buildings: A Methodological Proposal. Forests. 2020; 11 (8):881.

Chicago/Turabian Style

Amirhosein Shabani; Mahdi Kioumarsi; Vagelis Plevris; Haris Stamatopoulos. 2020. "Structural Vulnerability Assessment of Heritage Timber Buildings: A Methodological Proposal." Forests 11, no. 8: 881.

Journal article
Published: 11 June 2020 in Buildings
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Engineers usually use trial-and-error approaches for dealing with design problems where they need to find the most economical design of a structural element in terms of its material cost while satisfying all the safety requirements imposed by the design codes. In this study, we employ a genetic algorithm (GA) with a dominance-based tournament selection technique for dealing with this design challenge. The methodology is applied in the design of reinforced concrete rectangular-shaped isolated footings in accordance with the American Concrete Institute ACI 318-19. First, the footing is encoded into a set of decision variables and an objective function is defined to compute the total cost based on the different construction materials. Then, the compliance of the design with the ACI 318-19 code is enforced by a constraint function that takes into consideration all the demand–capacity ratios for the different resistance requirements such as the allowable bearing pressure of the supporting soil, and the shear and flexural capacities of the footing, among others. Two numerical examples are presented where the results show a significant advantage in terms of material-cost and design-time reduction in comparison with the commonly used trial and error approach, proving the applicability of optimization algorithms (OAs) into the everyday design routine of the structural engineer.

ACS Style

German Solorzano; Vagelis Plevris. Optimum Design of RC Footings with Genetic Algorithms According to ACI 318-19. Buildings 2020, 10, 110 .

AMA Style

German Solorzano, Vagelis Plevris. Optimum Design of RC Footings with Genetic Algorithms According to ACI 318-19. Buildings. 2020; 10 (6):110.

Chicago/Turabian Style

German Solorzano; Vagelis Plevris. 2020. "Optimum Design of RC Footings with Genetic Algorithms According to ACI 318-19." Buildings 10, no. 6: 110.

Journal article
Published: 04 May 2020 in Procedia Manufacturing
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Constrained optimization is a highly important field of engineering as most real-world optimization problems are associated with one or several constraints. Such problems are often challenging to solve due to their complexity and high nonlinearity. Differential evolution (DE) is arguably one of the most versatile and stable population-based search algorithms that exhibits robustness to multi-modal problems and has shown to be very efficient when solving constrained global optimization problems. In this paper we investigate the performance of several DE variants existing in the literature such as the traditional DE, the composite DE (CoDE), the adaptive DE with optional external archive (JADE) and the self-adaptive DE (jDE and SaDE), for handling constrained structural optimization problems. The performance of each DE variant is quantified by using three well-known benchmark structures in 2D and 3D. It is shown that JADE, which updates control parameters in an adaptive way, truly exhibits superior performance and outperforms the other DE variants in all the cases examined.

ACS Style

Manolis Georgioudakis; Vagelis Plevris. On the Performance of Differential Evolution Variants in Constrained Structural Optimization. Procedia Manufacturing 2020, 44, 371 -378.

AMA Style

Manolis Georgioudakis, Vagelis Plevris. On the Performance of Differential Evolution Variants in Constrained Structural Optimization. Procedia Manufacturing. 2020; 44 ():371-378.

Chicago/Turabian Style

Manolis Georgioudakis; Vagelis Plevris. 2020. "On the Performance of Differential Evolution Variants in Constrained Structural Optimization." Procedia Manufacturing 44, no. : 371-378.

Editorial article
Published: 08 April 2020 in Frontiers in Built Environment
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Editorial: Innovative Approaches in Computational Structural Engineering

ACS Style

George C. Tsiatas; Vagelis Plevris. Editorial: Innovative Approaches in Computational Structural Engineering. Frontiers in Built Environment 2020, 6, 1 .

AMA Style

George C. Tsiatas, Vagelis Plevris. Editorial: Innovative Approaches in Computational Structural Engineering. Frontiers in Built Environment. 2020; 6 ():1.

Chicago/Turabian Style

George C. Tsiatas; Vagelis Plevris. 2020. "Editorial: Innovative Approaches in Computational Structural Engineering." Frontiers in Built Environment 6, no. : 1.

Journal article
Published: 12 December 2019 in Mathematics
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This paper investigates the effect of computing the bearing capacity through different methods on the optimum construction cost of reinforced concrete retaining walls (RCRWs). Three well-known methods of Meyerhof, Hansen, and Vesic are used for the computation of the bearing capacity. In order to model and design the RCRWs, a code is developed in MATLAB. To reach a design with minimum construction cost, the design procedure is structured in the framework of an optimization problem in which the initial construction cost of the RCRW is the objective function to be minimized. The design criteria (both geotechnical and structural limitations) are considered constraints of the optimization problem. The geometrical dimensions of the wall and the amount of steel reinforcement are used as the design variables. To find the optimum solution, the particle swarm optimization (PSO) algorithm is employed. Three numerical examples with different wall heights are used to capture the effect of using different methods of bearing capacity on the optimal construction cost of the RCRWs. The results demonstrate that, in most cases, the final design based on the Meyerhof method corresponds to a lower construction cost. The research findings also reveal that the difference among the optimum costs of the methods is decreased by increasing the wall height.

ACS Style

Neda Moayyeri; Sadjad Gharehbaghi; Vagelis Plevris. Cost-Based Optimum Design of Reinforced Concrete Retaining Walls Considering Different Methods of Bearing Capacity Computation. Mathematics 2019, 7, 1232 .

AMA Style

Neda Moayyeri, Sadjad Gharehbaghi, Vagelis Plevris. Cost-Based Optimum Design of Reinforced Concrete Retaining Walls Considering Different Methods of Bearing Capacity Computation. Mathematics. 2019; 7 (12):1232.

Chicago/Turabian Style

Neda Moayyeri; Sadjad Gharehbaghi; Vagelis Plevris. 2019. "Cost-Based Optimum Design of Reinforced Concrete Retaining Walls Considering Different Methods of Bearing Capacity Computation." Mathematics 7, no. 12: 1232.

Review
Published: 01 January 2019 in Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)
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ACS Style

Vagelis Plevris; German Solorzano; Nikolaos Bakas. LITERATURE REVIEW OF HISTORICAL MASONRY STRUCTURES WITH MACHINE LEARNING. Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015) 2019, 1 .

AMA Style

Vagelis Plevris, German Solorzano, Nikolaos Bakas. LITERATURE REVIEW OF HISTORICAL MASONRY STRUCTURES WITH MACHINE LEARNING. Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015). 2019; ():1.

Chicago/Turabian Style

Vagelis Plevris; German Solorzano; Nikolaos Bakas. 2019. "LITERATURE REVIEW OF HISTORICAL MASONRY STRUCTURES WITH MACHINE LEARNING." Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015) , no. : 1.

Journal article
Published: 26 October 2018 in Journal of Computer Science
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Computer simulations and computational methods, such as the Finite Element Analysis (FEA) have become essential methodologies in science and engineering during the last decades, in a wide variety of academic fields. Six decades after the invention of the digital computer, advanced FE simulations are used to enhance and leapfrog theoretical and experimental progress, at different levels of complexity. Particularly in Civil and Structural Engineering, significant research work has been made lately on the development of FE simulation codes, methodologies and validation techniques for understanding the behavior of large and complex structures such as buildings, bridges, dams, offshore structures and others. These efforts are aimed at designing structures that are resilient to natural excitations (wind loads, earthquakes, floods) as well as human-made threats (impact, fire, explosion and others). The skill set required to master advanced FEA is inherently interdisciplinary, requiring in-depth knowledge of advanced mathematics, numerical methods and their computational implementation, as well as engineering sciences. In this paper, we focus on the importance of sound and profound engineering education and knowledge about the theory behind the Finite Element Method to obtain correct and reliable analysis results for designing real-world structures. We highlight common mistakes made by structural engineers while simulating complex structures and the risk of structural damage because of human-made mistakes or errors in the model assumptions. The event of the collapse and eventual sinking of a concrete offshore platform in the North Sea is presented as a case study where a serious error in the finite element analysis played a crucial role leading to structural failure and collapse.

ACS Style

Vagelis Plevris; Gro Markeset. Educational Challenges in Computer-based Finite Element Analysis and Design of Structures. Journal of Computer Science 2018, 14, 1351 -1362.

AMA Style

Vagelis Plevris, Gro Markeset. Educational Challenges in Computer-based Finite Element Analysis and Design of Structures. Journal of Computer Science. 2018; 14 (10):1351-1362.

Chicago/Turabian Style

Vagelis Plevris; Gro Markeset. 2018. "Educational Challenges in Computer-based Finite Element Analysis and Design of Structures." Journal of Computer Science 14, no. 10: 1351-1362.

Journal article
Published: 25 September 2018 in Heliyon
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OpenSeismoMatlab is an innovative open-source software for strong ground motion data processing, written in MATLAB. The software implements an elastoplastic bilinear kinematic hardening constitutive model and uses a state-of-the-art single step single solve time integration algorithm featuring exceptional speed, robustness and accuracy. OpenSeismoMatlab can calculate various time histories and corresponding peak values, Arias intensity and its time history, significant duration, various linear elastic response spectra and constant ductility inelastic response spectra, as well as Fourier amplitude spectrum and mean period. Due to its open-source nature, the software can be easily extended or modified, having high research and educational value for the professional engineering and research community. In the present paper, the structure, algorithms and main routines of the program are explained in detail and the results for various types of spectra of 11 earthquake strong ground motions are calculated and compared to corresponding results from other proprietary software.

ACS Style

George Papazafeiropoulos; Vagelis Plevris. OpenSeismoMatlab: A new open-source software for strong ground motion data processing. Heliyon 2018, 4, e00784 .

AMA Style

George Papazafeiropoulos, Vagelis Plevris. OpenSeismoMatlab: A new open-source software for strong ground motion data processing. Heliyon. 2018; 4 (9):e00784.

Chicago/Turabian Style

George Papazafeiropoulos; Vagelis Plevris. 2018. "OpenSeismoMatlab: A new open-source software for strong ground motion data processing." Heliyon 4, no. 9: e00784.

Research article
Published: 14 May 2018 in Advances in Civil Engineering
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Structural damage identification is a scientific field that has attracted a lot of interest in the scientific community during the recent years. There have been many studies intending to find a reliable method to identify damage in structural elements both in location and extent. Most damage identification methods are based on the changes of dynamic characteristics and static responses, but the incompleteness of the test data is a great obstacle for both. In this paper, a structural damage identification method based on the finite element model updating is proposed, in order to provide the location and the extent of structural damage using incomplete modal data of a damaged structure. The structural damage identification problem is treated as an unconstrained optimization problem which is solved using the differential evolution search algorithm. The objective function used in the optimization process is based on a combination of two modal correlation criteria, providing a measure of consistency and correlation between estimations of mode shape vectors. The performance and robustness of the proposed approach are evaluated with two numerical examples: a simply supported concrete beam and a concrete frame under several damage scenarios. The obtained results exhibit high efficiency of the proposed approach for accurately identifying the location and extent of structural damage.

ACS Style

Manolis Georgioudakis; Vagelis Plevris. A Combined Modal Correlation Criterion for Structural Damage Identification with Noisy Modal Data. Advances in Civil Engineering 2018, 2018, 1 -20.

AMA Style

Manolis Georgioudakis, Vagelis Plevris. A Combined Modal Correlation Criterion for Structural Damage Identification with Noisy Modal Data. Advances in Civil Engineering. 2018; 2018 ():1-20.

Chicago/Turabian Style

Manolis Georgioudakis; Vagelis Plevris. 2018. "A Combined Modal Correlation Criterion for Structural Damage Identification with Noisy Modal Data." Advances in Civil Engineering 2018, no. : 1-20.

Specialty grand challenge article
Published: 10 April 2018 in Frontiers in Built Environment
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Computational Structural Engineering: Past Achievements and Future Challenges

ACS Style

Vagelis Plevris; George C. Tsiatas. Computational Structural Engineering: Past Achievements and Future Challenges. Frontiers in Built Environment 2018, 4, 1 .

AMA Style

Vagelis Plevris, George C. Tsiatas. Computational Structural Engineering: Past Achievements and Future Challenges. Frontiers in Built Environment. 2018; 4 ():1.

Chicago/Turabian Style

Vagelis Plevris; George C. Tsiatas. 2018. "Computational Structural Engineering: Past Achievements and Future Challenges." Frontiers in Built Environment 4, no. : 1.

Original research article
Published: 31 July 2017 in Frontiers in Built Environment
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A new optimization concept is introduced which involves the optimization of nonlinear planar shear buildings by using gradients based on equivalent linear structures, instead of the traditional practice of calculating the gradients from the nonlinear objective function. The optimization problem is formulated as an equivalent linear system of equations in which a target fundamental eigenfrequency and equal dissipated energy distribution within the storeys of the building are the components of the objective function. The concept is applied in a modified Newton-Raphson algorithm in order to find the optimum stiffness distribution of two representative linear or nonlinear MDOF shear buildings, so that the distribution of viscously damped and hysteretically dissipated energy respectively over the structural height is uniform. A number of optimization results are presented in which the effect of the earthquake excitation, the critical modal damping ratio and the normalized yield interstorey drift limit on the optimum stiffness distributions is studied. Structural design based on the proposed approach is more rational and technically feasible compared to other optimization strategies (e.g. uniform ductility concept), whereas it is expected to provide increased protection against global collapse and loss of life during strong earthquake events. Finally, it is proven that the new optimization concept not only reduces running times by as much as 91% compared to the classical optimization algorithms, but also it can be applied in other optimization algorithms which use gradient information to proceed to the optimum point.

ACS Style

George Papazafeiropoulos; Vagelis Plevris; Manolis Papadrakakis. A New Energy-Based Structural Design Optimization Concept under Seismic Actions. Frontiers in Built Environment 2017, 3, 1 .

AMA Style

George Papazafeiropoulos, Vagelis Plevris, Manolis Papadrakakis. A New Energy-Based Structural Design Optimization Concept under Seismic Actions. Frontiers in Built Environment. 2017; 3 ():1.

Chicago/Turabian Style

George Papazafeiropoulos; Vagelis Plevris; Manolis Papadrakakis. 2017. "A New Energy-Based Structural Design Optimization Concept under Seismic Actions." Frontiers in Built Environment 3, no. : 1.

Journal article
Published: 08 January 2017 in European Journal of Environmental and Civil Engineering
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This paper investigates the mechanical properties of sandcrete mixes with metakaolin (MK) as a mineral additive. Three different types of binders were prepared: one used as reference, based on 100% w/w ordinary Portland cement (PC), and two modified, where MK replaced PC in percentages 10% or 20% by weight of the reference cement content. Experimental tests have been carried out in order to obtain the full stress–strain diagram for the material under uniaxial compressive loading. The results of the tests have been post-processed numerically in order to obtain various mechanical characteristics of the sandcrete material, such as compressive strength, modulus of elasticity and strain at maximum strength. It has been found that, in general, specimens with metakaolin in the binder exhibit enhanced compressive strength compared to the reference samples without metakaolin. The improvement in compressive strength was more pronounced in samples with higher concentration of binder (50% w/w) and low or medium water per binder (W/B) ratio. Samples with higher compressive strength were characterised by higher values for the measured ultrasonic pulse velocity. The strain values, recorded at maximum strength, are considerably higher than the strain value of 2‰ for concrete under uniaxial compressive load.

ACS Style

Panagiotis G. Asteris; Konstantinos G. Kolovos; Adamantia Athanasopoulou; Vagelis Plevris; Gerassimos Konstantakatos. Investigation of the mechanical behaviour of metakaolin-based sandcrete mixtures. European Journal of Environmental and Civil Engineering 2017, 23, 300 -324.

AMA Style

Panagiotis G. Asteris, Konstantinos G. Kolovos, Adamantia Athanasopoulou, Vagelis Plevris, Gerassimos Konstantakatos. Investigation of the mechanical behaviour of metakaolin-based sandcrete mixtures. European Journal of Environmental and Civil Engineering. 2017; 23 (3):300-324.

Chicago/Turabian Style

Panagiotis G. Asteris; Konstantinos G. Kolovos; Adamantia Athanasopoulou; Vagelis Plevris; Gerassimos Konstantakatos. 2017. "Investigation of the mechanical behaviour of metakaolin-based sandcrete mixtures." European Journal of Environmental and Civil Engineering 23, no. 3: 300-324.

Review
Published: 01 January 2017 in Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015)
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ACS Style

Vagelis Plevris; Nikolaos Bakas; Gro Markeset; John Bellos. LITERATURE REVIEW OF MASONRY STRUCTURES UNDER EARTHQUAKE EXCITATION UTILIZING MACHINE LEARNING ALGORITHMS. Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015) 2017, 2685 -2694.

AMA Style

Vagelis Plevris, Nikolaos Bakas, Gro Markeset, John Bellos. LITERATURE REVIEW OF MASONRY STRUCTURES UNDER EARTHQUAKE EXCITATION UTILIZING MACHINE LEARNING ALGORITHMS. Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015). 2017; ():2685-2694.

Chicago/Turabian Style

Vagelis Plevris; Nikolaos Bakas; Gro Markeset; John Bellos. 2017. "LITERATURE REVIEW OF MASONRY STRUCTURES UNDER EARTHQUAKE EXCITATION UTILIZING MACHINE LEARNING ALGORITHMS." Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2015) , no. : 2685-2694.

Book chapter
Published: 23 December 2016 in Computational Methods in Applied Sciences
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Nowadays, the design of concrete structures in Europe is governed by the application of Eurocode 2 (EC2). In particular, EC2—Part 1-1 deals with the general rules and the rules for concrete buildings. An important aspect of the design is specifying the necessary tensile (and compressive, if needed) steel reinforcement required for a Reinforced Concrete (RC) section. In this study we take into account the equivalent rectangular stress distribution for concrete and the bilinear stress-strain relation with a horizontal top branch for steel. This chapter presents three detailed methodologies for the design of rectangular cross sections with tensile reinforcement, covering all concrete classes, from C12/15 up to C90/105. The purpose of the design is to calculate the necessary tensile steel reinforcement. The first methodology provides analytic formulas and an algorithmic procedure that can be easily implemented in any programming language. The second methodology is based on design tables that are provided in Appendix A, requiring less calculations. The third methodology provides again analytic formulas that can replace the use of tables and even be used to reproduce the design tables. Apart from the direct problem, the inverse problem is also addressed, where the steel reinforcement is given and the purpose is to find the maximum bending moment that the section can withstand, given also the value and position of the axial force. For each case analytic relations are extracted in detail with a step-by-step procedure, the relevant assumptions are highlighted and results for four different cross section design examples are presented.

ACS Style

Vagelis Plevris; George Papazafeiropoulos. Design of RC Sections with Single Reinforcement According to EC2-1-1 and the Rectangular Stress Distribution. Computational Methods in Applied Sciences 2016, 205 -259.

AMA Style

Vagelis Plevris, George Papazafeiropoulos. Design of RC Sections with Single Reinforcement According to EC2-1-1 and the Rectangular Stress Distribution. Computational Methods in Applied Sciences. 2016; ():205-259.

Chicago/Turabian Style

Vagelis Plevris; George Papazafeiropoulos. 2016. "Design of RC Sections with Single Reinforcement According to EC2-1-1 and the Rectangular Stress Distribution." Computational Methods in Applied Sciences , no. : 205-259.

Original research paper
Published: 28 July 2016 in Bulletin of Earthquake Engineering
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The performance of a family of nonlinear generalized single step-single solve (GSSSS) time integration schemes is assessed by comparison of their results in terms of total energy and the agreement with respective results published in the literature. The nonlinear algorithms have been developed by their linear counterparts using a Newton–Raphson iterative procedure to ensure dynamic equilibrium inside each time step. A literature review of the available time integration schemes used for nonlinear problems and the family of linear GSSSS algorithms are presented along with several commonly used time integration algorithms as special cases. Afterwards, the nonlinear schemes are formulated, and outlined in an explicit flowchart, which describes the nonlinear integration procedure in detail. The nonlinear family of algorithms is applied to six benchmark problems involving the dynamic response of SDOF systems with various stiffness and damping properties, as well as to a 3dof structure representing finite element systems containing rigid connections, penalty factors and other such types of constraints. It is shown that the schemes with Continuous Acceleration formulation (such as the HHT-a method) perform in general better than the others, even with a large time step, which leads to reduced computational effort for the estimation of the nonlinear dynamic response with relatively little loss of accuracy.

ACS Style

George Papazafeiropoulos; Vagelis Plevris; Manolis Papadrakakis. A generalized algorithm framework for non-linear structural dynamics. Bulletin of Earthquake Engineering 2016, 15, 411 -441.

AMA Style

George Papazafeiropoulos, Vagelis Plevris, Manolis Papadrakakis. A generalized algorithm framework for non-linear structural dynamics. Bulletin of Earthquake Engineering. 2016; 15 (1):411-441.

Chicago/Turabian Style

George Papazafeiropoulos; Vagelis Plevris; Manolis Papadrakakis. 2016. "A generalized algorithm framework for non-linear structural dynamics." Bulletin of Earthquake Engineering 15, no. 1: 411-441.

Original article
Published: 20 January 2016 in Neural Computing and Applications
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In the last decades, a plethora of advanced computational models and techniques have been proposed on the modeling, assessment and design of masonry structures. The successful application of such sophisticated models necessitates the development of reliable analytical models capable of describing the failure of masonry materials. Nevertheless, there is a lack of analytical models due to the anisotropic and brittle nature exhibited by the masonry materials. In the present paper, the use of neural networks (NNs) is proposed to approximate the failure surface of masonry materials in dimensionless form. The comparison of the derived results with experimental findings as well as analytical results demonstrates the promising potential of using NNs for the reliable and robust approximation of the masonry failure surface under biaxial stress.

ACS Style

Panagiotis G. Asteris; Vagelis Plevris. Anisotropic masonry failure criterion using artificial neural networks. Neural Computing and Applications 2016, 28, 2207 -2229.

AMA Style

Panagiotis G. Asteris, Vagelis Plevris. Anisotropic masonry failure criterion using artificial neural networks. Neural Computing and Applications. 2016; 28 (8):2207-2229.

Chicago/Turabian Style

Panagiotis G. Asteris; Vagelis Plevris. 2016. "Anisotropic masonry failure criterion using artificial neural networks." Neural Computing and Applications 28, no. 8: 2207-2229.