Haris Alexakis

Aston University · School of Engineering and Applied Science

Skewed masonry arch railway bridges are common, yet their structural behaviour under typical working loads, along with gradual changes in behaviour due to degradation, can be difficult to determine. This paper aims to address this problem through detailed monitoring of a damaged, skewed masonry arch railway bridge in the UK, which was recently repa...

Developing early-warning sensor-based maintenance systems for ageing railway infrastructure, such as masonry arch bridges, can be a challenging task due to the difficulty of identifying degradation/damage as the source of small, gradual changes in sensor data, as opposed to other environmental and loading effects. This paper offers a new method of...

Ageing infrastructure, such as masonry railway bridges, suffers from structural deterioration due to fatigue loading. This paper presents an experimental study of brick masonry deterioration under gradually increasing cyclic loading with the aid of Acoustic Emission (AE) sensors. Two masonry beams were tested in the laboratory under similar stress...

Marsh Lane viaduct is a typical example of a 19th century brick masonry railway arch in the UK. It frequently carries passenger trains to and from Leeds Station. This paper broadly discusses the sensing techniques and associated analysis procedures used to (i) identify the reasons for existing damage, (ii) quantify their impact on the dynamic respo...

Skewed masonry arch bridges form an important part of the rail and road infrastructure networks in the UK, as well as other European countries. However, the precise flow of forces in these structures is not well understood, which can pose a problem when it comes to assessment and maintenance. The skewed masonry arch railway bridge considered in thi...

This study presents a multi-sensing monitoring system recently installed in a Victorian railway viaduct in Leeds, UK. The viaduct is in continuous use since its construction during the 19 th century and suffers extensive cracking due to the combined action of increased train loads and environmental effects. The bridge was retrofitted in 2015 and th...

The Marsh Lane viaduct is a masonry railway bridge constructed during the 19th century nearby Leeds Central Railway Station. The bridge appears significantly damaged due to the increase of the operational train loads over the last decades and due to environmental effects. Due to this degradation, extensive repair was conducted in 2015. After this r...

This paper studies the long term structural behaviour of a Victorian railway viaduct under train loading and temperature variation. A multi-sensing, self-sustaining and remotely controlled data acquisition system combines fibre Bragg grating strain sensors with acoustic emission sensors for the study of both global dynamic deformation and local mas...

This paper examines and compares the minimum horizontal acceleration that is needed to initiate uplift of the single-nave barrel vault and of the rocking frame which are the two most common masonry structural systems used to bridge a span. The paper concludes that regardless of the direction of the rupture of the buttresses, the single-nave barrel...

This paper investigates the limit states of a circular masonry arch supported on rectangular buttresses when subjected to lateral inertial loading in addition to gravity loading by employing the principle of stationary potential energy. Depending on the slenderness of the arch compared to the slenderness of the buttresses, the study identifies two...

In this paper we revisit the fracturing of masonry towers and buttresses when subjected to lateral loading. At their limit state, tall, slender masonry towers and buttresses collapse by pivoting about their base corner; whereas, less slender configurations may collapse by developing a shear failure. Because of the unilateral behavior of masonry, at...

This chapter revisits the limit equilibrium analysis of masonry arches when subjected to gravity and lateral loads. Firstly, the major contributions during the last three centuries either with geometric or energy formulations are discussed, and subsequently, the performance of the distinct element method (DEM) is examined against rigorous solutions...

This paper revisits the fracturing of masonry buttresses and towers when subjected either to a concentrated oblique force at their head or to lateral inertial loading due to ground shaking and presents the corresponding failure criteria in elongation and shear. The loading configurations examined result either from the thrust that an elevated arch...

In this paper we compute the minimum thickness and the location of the imminent intrados hinge of symmetric elliptical masonry arches when subjected to their weight. The paper explains that the problem of determining the minimum thickness of a masonry arch capable to support its own weight has multiple solutions. The infinite many neighboring solut...

In this paper, we revisit the limit equilibrium analysis of masonry arches. Firstly, the major contributions during the last three centuries associated with geometric and energy formulations are discussed, and subsequently, the paper explains that the problem of determining the minimum thickness of a masonry arch capable to support its own weight h...

More than a century ago Milankovitch presented for the first time the correct and complete solution for the theoretical minimum thickness, t, of a semicircular masonry arch with radius, R (t/R=0.1075). This paper uses a variational formulation approach and shows that this solution is not unique and that it depends on the stereotomy exercised.

More than a century ago Milankovitch presented a remarkable formulation for the thrust-line of arches that do not sustain tension, and by taking radial cuts he published for the first time the correct and complete solution for the theoretical minimum thickness, t, of a semicircular arch with radius, R. This paper shows that Milankovitch's solution,...

In this paper, we compute the location of the imminent hinges and the minimum thickness, t, of a circular masonry arch with mid-thickness radius, R, and embracing angle, β, which can just sustain its own weight together with a given level of a horizontal ground acceleration, ε g. Motivated from the recent growing interest in identifying the limit e...

In this paper, we compute the minimum thickness and the location of the imminent intrados hinge of symmetric elliptical masonry arches when subjected to their weight. While this problem (Couplet’s problem) was solved rigorously for semicircular arches more than a century ago, no results have been available for elliptical arches. Motivated from the...

More than a century ago, the Serbian engineer and astronomer Milutin Milankovitch presented a remarkable formulation for the thrust-line of arches that do not sustain tension, and by taking radial cuts and a polar coordinate system, he published for the first time the correct and complete solution for the theoretical minimum thickness, t, of a mono...

More than a century ago the Serbian engineer and astronomer Milutin Milankovitch presented a remarkable formulation for the thrust-line of arches that do not sustain tension, and using polar coordinates he published for the first time the correct and complete solution for the theoretical minimum thickness, t, of a semicircular arch with radius R. T...

More than a century ago the Serbian engineer and astronomer Milutin Milankovitch presented a remarkable formulation for the thrust-line of arches that do not sustain tension, and using polar coordinates he presented for the first time the correct and complete solution for the theoretical minimum thickness, t, of a semicircular arch with radius R. T...

In the archaeological site of Ancient Nemea, Greece, southeast of the Temple of Zeus, there is an ancient stadium in which the athletes of the past entered through a 36 m-long tunnel—a cut-and-cover vaulted structure, constructed of limestone. The tunnel was buried with earth until it was discovered in 1978. At present, some limestone blocks of the...