Vasilis Sarhosis

Vasilis Sarhosis
University of Leeds · School of CIvil Engineering

BSc, MSc, PhD, FHEA, CEng, FICE FIMEchE, MIMS
Inspection, assessment and monitoring of existing masonry infrastructure

About

177
Publications
91,615
Reads
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2,705
Citations
Introduction
Dr Sarhosis is an Associate Professor in Structural Engineering University of Leeds. He holds both undergraduate and postgraduate degrees in Civil Engineering and worked as a consultant Civil Engineer in UK. He is a Chartered Engineer (CEng) and a Fellow of the Higher Education Academy (FHEA) in UK. He is leading the Masonry Research Group and chairing the National Scientific Committee on the Analysis and Restoration of Structures of Architectural Heritage (ISCARSAH) which is part of ICOMOS.
Additional affiliations
February 2020 - present
University of Leeds
Position
  • Professor (Associate)
January 2016 - January 2019
Newcastle University
Position
  • Lecturer
April 2013 - January 2016
Cardiff University
Position
  • Research Associate

Publications

Publications (177)
Article
Full-text available
A study of the influence of the brick–mortar interface on the pre- and post-cracking behaviour of low bond strength masonry wall panels subjected to vertical in plane load is presented. Using software based on the Distinct Element Method (DEM), a series of computational models have been developed to represent low bond strength masonry wall panels c...
Article
Full-text available
This paper aims to improve automation in brick segmentation and crack detection of masonry walls through image-based techniques and machine learning. Initially, a large dataset of hand-labelled images of different in colour, texture, and size of brickwork masonry walls has been developed. Then, different deep learning networks (U-Net, DeepLabV3+, U...
Article
Full-text available
Two strong earthquakes hit Thessaly region on March 3rd, 2021 (M w = 6.3) and on March 4th, 2021 (M w = 6.1). The epicentres of the earthquakes were located at approximately 23 and 29 km respectively NW of Larissa, one of the most populous cities in Greece. Several aftershocks followed thereafter. Although no injuries were recorded, several structu...
Technical Report
Full-text available
Technical report with multiple authors (please refer to pdf), edited by Anastasios Sextos, Basil Margaris and Nikolaos Klimis. Coordinated by the Hellenic Association of Earthquake Engineering, the Institute of Engineering Seismology and Earthquake Engineering (ITSAK-EPPO) and Democritus University of Thrace with the collaboration of Aristotle Univ...
Article
Full-text available
A detailed modelling approach to represent masonry at the meso-scale is proposed, based on the discrete element method, considering the nonlinear behavior of the joints and the units. The fracture of units is represented by the bonded-block concept, in which a random network of potential cracks is created, allowing the progressive development of fa...
Article
Full-text available
A detailed modelling approach to represent masonry at the meso-scale is proposed, based on the discrete element method, considering the nonlinear behavior of the joints and the units. The fracture of units is represented by the bonded-block concept, in which a random net-work of potential cracks is created, allowing the progressive development of f...
Article
Full-text available
The mechanical properties of masonry, both in the linear elastic range and after the onset of damage, are dependent on the geometric and mechanical properties of its constituent materials: the units and the mortar. Finite element micromodelling, while capable of providing accurate and comprehensive results, is associated with high computational cos...
Article
Full-text available
A homogenisation scheme based on inclusion modelling is coupled with constitutive laws for damage and implemented in a finite element model for the simulation of concrete and reinforcement bar damage in reinforced concrete structures. The scheme is employed for simulating the behaviour of evenly distributed reinforcement and adapted for the simulat...
Article
Full-text available
Historical masonry arch bridges still form an important part of Croatian transportation network. There are approximately 680 masonry arch bridges and culverts currently being used for railways and roadways. Many of these bridges are relatively old (more than hundred years in most cases) but still in usage. Increasing vehicle load and speeds as well...
Article
Full-text available
Within the scope of literature, the influence of openings within the infill walls that are bounded by a reinforced concrete frame and excited by seismic drift forces in both in- and out-of-plane direction is still uncharted. Therefore, a 3D micromodel was developed and calibrated thereafter, to gain more insight in the topic. The micromodels were c...
Article
Masonry panels consisting of piers and spandrels in buildings are vulnerable to in-plane actions caused by seismicity and soil subsidence. Tectonic seismicity is a safety hazard for masonry structures, whereas low-magnitude induced seismicity can be detrimental to their durability due to the accumulation of light damage. This is particularly true i...
Article
In this work, a simple and effective Rigid Beam Model recently introduced for studying the dynamic behaviour of ancient freestanding stone columns is extended to the case of cantilever unreinforced masonry walls, considered along their thickness and subjected to out-of-plane loading. Both monolithic and multi-block walls were investigated. The prop...
Article
Full-text available
Over the last 50 years, research has mainly focused on characterizing the In-Plane behaviour of unreinforced masonry infill walls. Recently, the focus of research has been addressed to understanding Out-of-Plane behaviour, also from the experimental point of view. However, in the experimental campaigns, there is high variability in the geometrical...
Article
Three-leaf masonry panels are typically composed of external leaves of irregularly bonded units and a rouble infill. The complexity of the response of these structures to mechanical loading arises from: a) the interaction of the leaves and b) the irregularity of the bond pattern of the outer leaves. This complexity makes analytical and computationa...
Conference Paper
This study offers a review of masonry arch bridges in Croatia, it presents their most common typologies, geometric characteristics, and damages. Data about bridges have been collected from official institutions, state archives, and conservation institutes. Statistical analysis considering materials, arch geometry, arch thickness, number of spans, a...
Conference Paper
U radu je dan pregled zidanih svođenih mostova u Republici Hrvatskoj, njihovih tipoloških obilježja i opaženih oštećenja. Podatci o mostovima su prikupljani od ovlaštenih ustanova, državnih arhiva i restauratorskih zavoda. Podatci su statistički obrađeni uzimajući u obzir gradivo, geometrijska svojstva, debljinu svoda (luka), broj raspona i otvoren...
Chapter
The state of Himachal Pradesh in India is located along the foothills of the Himalayas comprising steep terrain, mountainous region and valleys. Approximately 70% of the residential and heritage buildings in the region are made of unreinforced masonry constructed using locally available materials such as mud bricks, stones and timber composites. Th...
Conference Paper
The state of Himachal Pradesh in India is located along the foothills of the Himalayas comprising steep terrain, mountainous region and valleys. Approximately 70% of the residential and heritage buildings in the region are made of unreinforced masonry constructed using locally available materials such as mud bricks, stones and timber composites. Th...
Article
Full-text available
In the seismic performance assessment of reinforced concrete (RC) frames, a reliable estimation of the capacity of unreinforced masonry (URM) infill walls is of utmost importance to ensure structural safety conditions. With particular attention to the out-of-plane (OoP) capacity of URM infill walls after in-plane (IP) damage, the issue of defining...
Article
Full-text available
This paper aims to quantify the evolution of damage in masonry walls under induced seismicity. A damage index equation, which is a function of the evolution of shear slippage and opening of the mortar joints, as well as of the drift ratio of masonry walls, was proposed herein. Initially, a dataset of experimental tests from in-plane quasi-static an...
Article
This paper presents approaches for the employment of non-contact sensing to enhance both the efficiency and reliability of numerical modelling of historic masonry. It commences with a thorough review of the high-level numerical modelling approaches of historic masonry. Following, the accuracy and cost-effectivity of available non-contact sensing te...
Article
Full-text available
Here we present a joint analysis of the geodetic, seismological and geological data of the March 2021 Northern Thessaly seismic sequence, that were gathered and processed as of April 30, 2021. First, we relocated seismicity data from regional and local networks and inferred the dip-direction (NE) and dip-angle (38°) of the March 3, 2021 rupture pla...
Article
This paper presents the development of an experimental campaign to investigate the cyclic, out-of-plane response of reinforced concrete frames containing masonry infill walls, using non-contact optical techniques to measure contour strains and deformations. Bare RC frames, as well as fully infilled walls, both with and without window and door openi...
Article
Full-text available
This paper presents a proof of concept for monitoring masonry structures using two different types of markers which are not easily noticeable by human eye but exhibit high reflection when subjected to NIR (near-infrared) wavelength of light. The first type is a retroreflective marker covered by a special tape that is opaque in visible light but tra...
Conference Paper
Full-text available
Fragility assessment of unreinforced masonry (URM) infill walls under seismic loads is a current research topic for large scale risk analysis of reinforced concrete frame structures. In this paper, Out-of-Plane (OoP) fragility functions are developed by probabilistic approach based on Monte Carlo simulations employing a numerical macro-element mode...
Article
Engineering efficiency is paramount for the introduction of novel systems and formats of analysis. This work extends an accessible and efficient analysis platform by combining the kinematic equilibrium approach of limit analysis with the single degree of freedom nature of a hinge-controlled masonry arch to perform dynamic modelling of applied two-d...
Article
Full-text available
A vital aspect when modelling the mechanical behaviour of existing masonry structures is the accuracy in which the geometry of the real structure is transferred in the numerical model. Commonly, the geometry of masonry is captured with traditional techniques (e.g. visual inspection and manual surveying methods), which are labour intensive and error...
Article
Full-text available
Masonry structures represent the highest proportion of building stock worldwide. Currently, the structural condition of such structures is predominantly manually inspected which is a laborious, costly and subjective process. With developments in computer vision, there is an opportunity to use digital images to automate the visual inspection process...
Article
Full-text available
On 28 December 2020, seismic activity in the wider Petrinja area strongly intensified after a period of relative seismological quiescence that had lasted more than 100 years (since the well-known M5.8 Kupa Valley earthquake of 1909, which is known based on the discovery of the Mohorovičić discontinuity). The day after the M5 foreshock, a destructiv...
Article
The aim of this paper is to quantify the effect of geometric uncertainty on the structural behaviour of arches developed using traditional geospatial and remote sensing techniques. Geometric models of twenty-five dry-jointed, rigid block arch specimens were developed using the proposed “Image2DEM” framework, encompassing the Structure-from-Motion (...
Article
Full-text available
During the 2015 Gorkha earthquake of 7.8 Mw that hit Kathmandu Valley, Nepal, numerous Nepalese Pagodas suffered extensive damage while others collapsed. Risk reduction strategies implemented in the region focused on disassembling historical structures and rebuilding them with modern material without in depth analysis of why they suffer damage and...
Article
The aim of this paper is to present the development of discontinuous approaches to simulate the nonlinear dynamic behaviour of the civic clock tower of Rotella, in the province of Ascoli Piceno (Italy). The study involves the use of the Non-Smooth Contact Dynamics method implemented in the LMGC90© code, where sliding motions are governed by Signori...
Conference Paper
In this contribution, a simple and effective Rigid Beam Model, recently introduced for simulating the dynamic behavior of slender freestanding masonry columns and walls, is adopted and improved for studying masonry chimneys. These structures represent a particular masonry building typology, characterized by a conical shape with a very large slender...
Article
Full-text available
The paper deals with an assessment of the seismic fragility of multi-drum ancient columns in the probabilistic assessment framework of incremental dynamic analysis (IDA). The dynamic response of multi-drum ancient is governed by the motion of stone-drums which can rock and slide individually or in group, individuating different possible collapse me...
Article
Masonry arch bridges form an integral part of our rail infrastructure network and their safety is important for the functioning of our society. Although, there have been several studies to understand the in-service condition of masonry arch bridges, these are mainly focusing on static analyses. However, it is well known that moving vehicles exert a...
Article
This paper presents a framework for the three-dimensional structural analysis of full scale, geometrically complex rubble masonry structures from point clouds generated from Structure-from-Motion photogrammetry or terrestrial laser scanning. According to the method, a point-based voxelization algorithm was adopted, whereby a dense point cloud was d...
Article
This paper presents an experimental and numerical study on the mechanical behaviour of masonry triplets subjected to monotonic and cyclic shear loadings. Masonry triplets were constructed with fired bricks bonded together with three different in composition (i.e. cement-to-sand ratios) mortars. Shear tests on triplets show that cyclic loading signi...
Conference Paper
2020 European Association for Structural Dynamics. All rights reserved. In the present paper has been reported the Non-Smooth Contact Dynamics method (NSCD) used for the damage evaluation of the multiple leaf masonry walls of the medieval fortress of Arquata del Tronto, strongly affected by the last Centre Italy earthquakes of August and October 20...
Article
A dynamic analysis procedure for hinge-controlled masonry arches subjected to horizontal acceleration profiles is developed. Constructed from the principle of energy conservation, the establishment of equivalent systems and the path independence of conservative work, a time-incremental analysis structure is established for kinematic propagation. Eq...
Article
Full-text available
The 2015 Gorkha Earthquake was a humanitarian disaster but also a cultural catastrophe that damaged and destroyed historic monuments across Nepal, including those within the Kathmandu Valley UNESCO World Heritage Property. In the rush to rebuild, traditionally constructed foundations are being removed and replaced with modern materials without asse...
Conference Paper
This paper presents the evaluation of the shear response and failure mode of masonry triplets subjected to monotonic and cyclic shear loadings. In this experimental campaign, different ma-sonry triplets have been constructed using different mortar composition and have been subject-ed to different levels of pre-compression. The cohesion and internal...
Article
Full-text available
This paper presents a literature review of research undertaken on the out-of-plane behaviour of masonry infilled frames. This paper also discusses the effects of bidirectional loads, openings, slenderness, boundary conditions etc. As numerous researchers have reported, these effects play a crucial role in achieving arching action cause, as they can...
Article
Full-text available
This paper presents an investigation of the collapse of a 325-year-old multi-tiered heritage temple during the 2015 Gorkha earthquake in Kathmandu, Nepal. The research comprises a reconnaissance survey followed by a geotechnical investigation and numerical back-analysis carried out to understand the potential causes of the collapse. The assessment...
Conference Paper
Masonry is a heterogeneous anisotropic material, which is composed of units (e.g. bricks, stones, blocks etc.), bonded together with or without mortar. It is probably the oldest building material that is commonly used today. Although masonry is easy to construct, its mechanical behavior is non-linear and thus complex to understand. The need to pred...
Article
In case of induced seismicity, expectations from a structural monitoring system are different than in the case of natural seismicity. In this paper, monitoring results of a historical building in Groningen (Netherlands) in case of induced seismicity has been presented. Results of the monitoring, particularities of the monitoring in case of induced...
Article
Full-text available
Today, there are several computational models to predict the mechanical behaviour of masonry structures subjected to external loading. Such models require the input of material parameters to describe the mechanical behaviour and strength of masonry constructions. Although such masonry material parameters are characterised by stochastic-probabilisti...
Article
Full-text available
Masonry arches are vulnerable to seismic actions. Over the last few years, extensive research has been carried out to develop strategies and methods for their seismic assessment and strengthening. The application of constant horizontal accelerations to masonry arches is a well-known quasi-static method, which approximates dynamic loading effects an...
Conference Paper
In this paper, a novel modelling approach based on the discrete element method for the simulation of backfill material in masonry arch bridges has been proposed. According to the method, bricks in the barrel vault are represented as an assembly of distinct blocks separated by zero thickness interfaces at each mortar joint while backfill is represen...
Chapter
In the presented work the mechanical behavior of a masonry arch bridge of a single-track railway is analyzed numerically. The 3D discrete element model contains the arch barrel, the backfill and the spandrel walls as well. Every voussoir is represented by a discrete element, while the backfill is modelled as an elasto-plastic continuum. Between the...
Article
Full-text available
Aims The paper analyzes the effectiveness of tuned liquid damper in controlling the vibration of high rise building. The new contribution is considering the fluid-structure interaction of a water tank as a Tuned Liquid Dampers (TLD). Background Currently, buildings are being built higher and higher, which requires TLDs to be larger as well. Theref...
Conference Paper
Full-text available
Masonry arches are vulnerable to seismic actions. Over the last few years, extensive research has developed strengthening strategies and methods to resist these seismic actions. However, from such studies, it is evident that the application of reinforcement to a masonry arch is done such that its failure limit is transformed from stability to a str...
Conference Paper
Kathmandu, the capital city of Nepal experienced a cultural catastrophe in the aftermath of the 2015 Gorkha Earthquake (Mw=7.8) which destroyed hundreds of historical and cultural monuments. Five out of the seven mountain zones within Kathmandu’s UNESCO World Heritage Sites suffered damage ranging from the complete collapse of several temples near...
Article
In this study, the performance at failure of old multi-tiered temples in Nepal under horizontal loads mimicking a seismic action has been addressed using three different computational approaches, including a) linear elastic; b) nonlinear static; and c) nonlinear dynamic analyses. Also, a sensitivity study was undertaken to understand the influence...
Article
This paper investigates the mechanical behaviour of skew masonry arch bridges taking into account the arch ring-backfill interaction. A numerical model has been developed using the three-dimensional computational software 3DEC, based on the Discrete Element Method of analysis. Each brick of the masonry skew arch was represented as a distinct block....