Paul Archbold | Athlone Institute of Technology (original) (raw)
Papers by Paul Archbold
Construction Technologies and Architecture
Fibre-reinforced concrete (FRC) is widely employed in the construction industry, with assorted fi... more Fibre-reinforced concrete (FRC) is widely employed in the construction industry, with assorted fibre types being used for different applications. Typically, steel fibres give additional tensile strength to the mixture, while flexible fibres may be used in large sections, such as floor slabs, to control crack width and to improve the handling ability of precast sections. For many reasons, including durability concerns, environmental impact, thermal performance, etc, alternatives to the currently available fibres are being sought. This study examines the potential of using basalt fibres, a mineral and natural material, as reinforcement of concrete sections in comparison to steel fibres and plain concrete mix. Mixes were tested containing 0.5% and 1.0% of basalt fibres measuring 25mm length, 0.5% of the same material with 48mm length and steel fibres measuring 50mm by 0.05%, 0.1%, 0.15% and 0.2% of the concrete volume. For the mechanical performance analysis, the 3-point bending test w...
Construction Technologies and Architecture
Natural fibre reinforced concrete is been studied for many years as a more sustainable option to ... more Natural fibre reinforced concrete is been studied for many years as a more sustainable option to current reinforced concrete used in industry. The most common fibre materials currently adopted are steel, glass and synthetic fibres. Apart from the high oxidation and cost, their environmental impact is a serious issue as they are petroleum-based materials. This study assesses the feasibility of replacing polypropylene fibre with hemp and flax fibres. According to the inventory of carbon and energy (ICE) the embodied energy of polypropylene (PP) is 95.4MJ/kg and the embodied carbon is 4.98kgCO2/kg during its lifetime. It represents approximately 3 times more than the estimated values for vegetable fibres. For this, Different concrete mixtures reinforced by 0.5% to 1.0% of hemp, flax and polypropylene fibres were tested, and their post-crack flexural tensile strength, elastic’s modulus, compressive strength and fracture energy were evaluated. The mixtures containing hemp fibres presente...
Abstract: Traditionally, high yield steel has been the common method of providing reinforcement i... more Abstract: Traditionally, high yield steel has been the common method of providing reinforcement in concrete, primarily due to its high tensile strength. However, steel is susceptible to corrosion, particularly in aggressive environments, leading to potential durability concerns and high costs in repair and maintenance. A promising solution to the problem is the use of fibre reinforced polymers (FRP) as a replacement for reinforcing steel. The use of FRP as reinforcement offers the following advantageous properties: it is lightweight and has high tensile strength, corrosion resistance and flexibility. It is intended in this paper to study the effects of innovative fibre composite materials for reinforcing concrete. This study looks at the use of both basalt FRP rods and carbon FRP grid (C-Grid) as potential alternative reinforcement materials to address the problem of corrosion. The investigation includes an experimental program to evaluate the structural performance of concrete pane...
Walking trials have been carried out on rigid and flexible walkways mounted with a force plate in... more Walking trials have been carried out on rigid and flexible walkways mounted with a force plate in order to determine how vertical pedestrian loading is influence by these two walking platforms. This paper presents the results of this study. The sample population comprised of seven healthy adults and involved over 40 trial walks at normal pacing velocities. The results report dynamic load factors from both single and continuous loading in terms of both walkways. Furthermore, it presents the relationship between pacing velocity and dynamic pedestrian loading in an endeavour to try and model such loading. It is envisaged that the data contained in this paper could contribute to the improvement of existing numerical load models for simulating pedestrian loading scenarios.
The use of fibres as reinforcement of composites is widely applicable for mechanical, materials a... more The use of fibres as reinforcement of composites is widely applicable for mechanical, materials and construction sectors. For instance, most of those fibres are not produced from renewable sources or by ecological procedures and researchers have been trying to develop smart solutions to replace them efficiently keeping a competitive price. Natural fibres are commonly considered as an ecologic alternative. They can be extracted from abundant vegetable, mineral or animal sources and if submitted to adequate treatment, they are able of providing important materials for the industry. Despite the aim of this paper is focused on concrete, results obtained experimentally for this study are still applicable for other purposes of application. Considering natural fibres as light and low-cost materials, when added to a composite mixture, they can become a sustainable alternative for other fibres to produce materials with better thermo-acoustic properties and reducing weight and density of the ...
ABSTRACT Bridge decks and underground service structures are often exposed to extreme environment... more ABSTRACT Bridge decks and underground service structures are often exposed to extreme environmental conditions where structural damage due to corrosion is a common phenomenon. This results in reduced service life and expensive repairs. Fibre Reinforced Polymer (FRP) products such as reinforcing rods offer a potential viable alternative to the steel reinforcement, which would allow better service life for structures and much reduced concrete cover as theses bars require minimal environmental protection. Higher service life and reduced quantities of concrete used in FRP reinforced concrete structures can be an attractive feature in terms of sustainability. Carbon FRP (CFRP), Basalt FRP (BFRP) and Glass FRP (GFRP) are the popular corrosion resistant bars that can be used to replace steel to produce more sustainable structures. A case study of two research investigations is discussed in this paper where GFRP and BFRP were used to replace the steel reinforcement without compromising strength and service behaviour of the structures. A comparison between the behaviour of steel reinforced structures with similar FRP reinforced structures and the advantages of building sustainable infrastructure using corrosion resistant reinforcement is also discussed in this paper.
Lecture Notes in Civil Engineering
Footbridge 2017 Berlin - Tell A Story: Conference Proceedings 6-8.9.2017 TU-Berlin
Pedestrian loading on flexible structures such as footbridges, grandstands and lightweight floors... more Pedestrian loading on flexible structures such as footbridges, grandstands and lightweight floors is an area, which is receiving significant attention from the research community of late. Of particular interest is the interaction between the pedestrian loading and the structural response of the loaded structure. This paper describes the design and dynamic analysis of a laboratory-scale FRP composite footbridge, constructed to study human-structure interaction. The bridge was specifically designed to have a natural frequency within the range excitable by human walking. It will be used to investigate the interaction between loads produced by walking and running pedestrians and the vibration of the structure which they are traversing.
The issue of structural condition monitoring is becoming increasingly important as the Ireland's ... more The issue of structural condition monitoring is becoming increasingly important as the Ireland's and the world's civil engineering infrastructure ages. An efficient monitoring process is essential as part of a modern infrastructure management system. Automated monitoring processes offer advantages over traditional, subjective techniques including repeatability, reliability and flexibility. They also offer potential for incorporation into remote monitoring systems. This paper presents a technique developed by the authors for detecting damage in steel laboratory scale beams by identification of changes in the natural frequencies of the first four vertical modes of vibration of the beams. This method was successfully employed to both locate and quantify a range of actual damage scenarios. Using twelve damage scenarios, this method successfully detected the damage location 92% of the time, while detecting the magnitude of the damage with a 75% success rate.
The issue of excessive vibrations of footbridges due to the passage of pedestrians has been well ... more The issue of excessive vibrations of footbridges due to the passage of pedestrians has been well documented in the past decade. Despite this there still remains great uncertainty as to how to predict the acceleration response of a footbridge due to crowd loading. This paper investigates the vibration response of a flexible footbridge subjected to crowd loading. Using a statistical model which caters for the variability of pedestrians, the vibration response of the footbridge is obtained. In this work, the effect of social groups or clusters of pedestrians in a crowd is investigated. Herein a cluster is defined as two or more pedestrians walking together with the same velocity. The predictions of this model are compared to a model which uses only lone pedestrians walking within a crowd. None of the current design codes or guidelines considers the possibility of pedestrians walking together. The size of the clusters is found in literature to follow a Poisson distribution. In this paper variations of the probability of clusters appearing in the crowd are assessed. It is found that the response of a crowd with clusters present is similar to the predictions of the UK National Annex to Eurocode 1.
The characteristic vertical vibration of a flexible footbridge subject to crowd loading is examin... more The characteristic vertical vibration of a flexible footbridge subject to crowd loading is examined in this paper. Typically, bridge vibrations produced from a crowd of pedestrians are estimated by using an enhancement factor applied to the effect caused by a single pedestrian. In this paper, a single pedestrian model, represented by a spring mass damper, which incorporates variables such as pedestrian mass and body stiffness, is used to calibrate a computationally efficient moving force model. This calibrated moving force model is further used in Monte Carlo simulations of non-homogenous crowds to estimate characteristic vertical vibration levels. Enhancement factors, which could be applied to simple single pedestrian moving force models in estimating the response due to a crowd are thus derived. Such enhancement factors are then compared to previously published values. It is found that the greatest difference between the spring mass damper and moving force models respectively occurs when the bridge frequency is at the mean crowd pacing frequency. For bridges with frequencies even slightly removed from this mean, moving force models appear adequate.
Reusable learning objects may be considered to be pre-developed digital learning activities that ... more Reusable learning objects may be considered to be pre-developed digital learning activities that may be integrated into lessons, modules, and courses. Their advantages include their flexibility of content, their accessibility and the possibilities of using them as a means of evaluation. The aim of this project was to develop such an object for use in teaching structural engineering. A review of best practice in development of reusable learning objects was conducted, followed by a suitability analysis of various software packages available for use in the development of the resource. A reusable learning object to be used in the teaching of the principle of second moment of area was developed. This interactive resource was made accessible through a virtual learning environment (Moodle) and accessed by students from engineering and non-engineering programmes in both AIT and GMIT, who provided feedback on the object via an online survey.
Construction Technologies and Architecture
Fibre-reinforced concrete (FRC) is widely employed in the construction industry, with assorted fi... more Fibre-reinforced concrete (FRC) is widely employed in the construction industry, with assorted fibre types being used for different applications. Typically, steel fibres give additional tensile strength to the mixture, while flexible fibres may be used in large sections, such as floor slabs, to control crack width and to improve the handling ability of precast sections. For many reasons, including durability concerns, environmental impact, thermal performance, etc, alternatives to the currently available fibres are being sought. This study examines the potential of using basalt fibres, a mineral and natural material, as reinforcement of concrete sections in comparison to steel fibres and plain concrete mix. Mixes were tested containing 0.5% and 1.0% of basalt fibres measuring 25mm length, 0.5% of the same material with 48mm length and steel fibres measuring 50mm by 0.05%, 0.1%, 0.15% and 0.2% of the concrete volume. For the mechanical performance analysis, the 3-point bending test w...
Construction Technologies and Architecture
Natural fibre reinforced concrete is been studied for many years as a more sustainable option to ... more Natural fibre reinforced concrete is been studied for many years as a more sustainable option to current reinforced concrete used in industry. The most common fibre materials currently adopted are steel, glass and synthetic fibres. Apart from the high oxidation and cost, their environmental impact is a serious issue as they are petroleum-based materials. This study assesses the feasibility of replacing polypropylene fibre with hemp and flax fibres. According to the inventory of carbon and energy (ICE) the embodied energy of polypropylene (PP) is 95.4MJ/kg and the embodied carbon is 4.98kgCO2/kg during its lifetime. It represents approximately 3 times more than the estimated values for vegetable fibres. For this, Different concrete mixtures reinforced by 0.5% to 1.0% of hemp, flax and polypropylene fibres were tested, and their post-crack flexural tensile strength, elastic’s modulus, compressive strength and fracture energy were evaluated. The mixtures containing hemp fibres presente...
Abstract: Traditionally, high yield steel has been the common method of providing reinforcement i... more Abstract: Traditionally, high yield steel has been the common method of providing reinforcement in concrete, primarily due to its high tensile strength. However, steel is susceptible to corrosion, particularly in aggressive environments, leading to potential durability concerns and high costs in repair and maintenance. A promising solution to the problem is the use of fibre reinforced polymers (FRP) as a replacement for reinforcing steel. The use of FRP as reinforcement offers the following advantageous properties: it is lightweight and has high tensile strength, corrosion resistance and flexibility. It is intended in this paper to study the effects of innovative fibre composite materials for reinforcing concrete. This study looks at the use of both basalt FRP rods and carbon FRP grid (C-Grid) as potential alternative reinforcement materials to address the problem of corrosion. The investigation includes an experimental program to evaluate the structural performance of concrete pane...
Walking trials have been carried out on rigid and flexible walkways mounted with a force plate in... more Walking trials have been carried out on rigid and flexible walkways mounted with a force plate in order to determine how vertical pedestrian loading is influence by these two walking platforms. This paper presents the results of this study. The sample population comprised of seven healthy adults and involved over 40 trial walks at normal pacing velocities. The results report dynamic load factors from both single and continuous loading in terms of both walkways. Furthermore, it presents the relationship between pacing velocity and dynamic pedestrian loading in an endeavour to try and model such loading. It is envisaged that the data contained in this paper could contribute to the improvement of existing numerical load models for simulating pedestrian loading scenarios.
The use of fibres as reinforcement of composites is widely applicable for mechanical, materials a... more The use of fibres as reinforcement of composites is widely applicable for mechanical, materials and construction sectors. For instance, most of those fibres are not produced from renewable sources or by ecological procedures and researchers have been trying to develop smart solutions to replace them efficiently keeping a competitive price. Natural fibres are commonly considered as an ecologic alternative. They can be extracted from abundant vegetable, mineral or animal sources and if submitted to adequate treatment, they are able of providing important materials for the industry. Despite the aim of this paper is focused on concrete, results obtained experimentally for this study are still applicable for other purposes of application. Considering natural fibres as light and low-cost materials, when added to a composite mixture, they can become a sustainable alternative for other fibres to produce materials with better thermo-acoustic properties and reducing weight and density of the ...
ABSTRACT Bridge decks and underground service structures are often exposed to extreme environment... more ABSTRACT Bridge decks and underground service structures are often exposed to extreme environmental conditions where structural damage due to corrosion is a common phenomenon. This results in reduced service life and expensive repairs. Fibre Reinforced Polymer (FRP) products such as reinforcing rods offer a potential viable alternative to the steel reinforcement, which would allow better service life for structures and much reduced concrete cover as theses bars require minimal environmental protection. Higher service life and reduced quantities of concrete used in FRP reinforced concrete structures can be an attractive feature in terms of sustainability. Carbon FRP (CFRP), Basalt FRP (BFRP) and Glass FRP (GFRP) are the popular corrosion resistant bars that can be used to replace steel to produce more sustainable structures. A case study of two research investigations is discussed in this paper where GFRP and BFRP were used to replace the steel reinforcement without compromising strength and service behaviour of the structures. A comparison between the behaviour of steel reinforced structures with similar FRP reinforced structures and the advantages of building sustainable infrastructure using corrosion resistant reinforcement is also discussed in this paper.
Lecture Notes in Civil Engineering
Footbridge 2017 Berlin - Tell A Story: Conference Proceedings 6-8.9.2017 TU-Berlin
Pedestrian loading on flexible structures such as footbridges, grandstands and lightweight floors... more Pedestrian loading on flexible structures such as footbridges, grandstands and lightweight floors is an area, which is receiving significant attention from the research community of late. Of particular interest is the interaction between the pedestrian loading and the structural response of the loaded structure. This paper describes the design and dynamic analysis of a laboratory-scale FRP composite footbridge, constructed to study human-structure interaction. The bridge was specifically designed to have a natural frequency within the range excitable by human walking. It will be used to investigate the interaction between loads produced by walking and running pedestrians and the vibration of the structure which they are traversing.
The issue of structural condition monitoring is becoming increasingly important as the Ireland's ... more The issue of structural condition monitoring is becoming increasingly important as the Ireland's and the world's civil engineering infrastructure ages. An efficient monitoring process is essential as part of a modern infrastructure management system. Automated monitoring processes offer advantages over traditional, subjective techniques including repeatability, reliability and flexibility. They also offer potential for incorporation into remote monitoring systems. This paper presents a technique developed by the authors for detecting damage in steel laboratory scale beams by identification of changes in the natural frequencies of the first four vertical modes of vibration of the beams. This method was successfully employed to both locate and quantify a range of actual damage scenarios. Using twelve damage scenarios, this method successfully detected the damage location 92% of the time, while detecting the magnitude of the damage with a 75% success rate.
The issue of excessive vibrations of footbridges due to the passage of pedestrians has been well ... more The issue of excessive vibrations of footbridges due to the passage of pedestrians has been well documented in the past decade. Despite this there still remains great uncertainty as to how to predict the acceleration response of a footbridge due to crowd loading. This paper investigates the vibration response of a flexible footbridge subjected to crowd loading. Using a statistical model which caters for the variability of pedestrians, the vibration response of the footbridge is obtained. In this work, the effect of social groups or clusters of pedestrians in a crowd is investigated. Herein a cluster is defined as two or more pedestrians walking together with the same velocity. The predictions of this model are compared to a model which uses only lone pedestrians walking within a crowd. None of the current design codes or guidelines considers the possibility of pedestrians walking together. The size of the clusters is found in literature to follow a Poisson distribution. In this paper variations of the probability of clusters appearing in the crowd are assessed. It is found that the response of a crowd with clusters present is similar to the predictions of the UK National Annex to Eurocode 1.
The characteristic vertical vibration of a flexible footbridge subject to crowd loading is examin... more The characteristic vertical vibration of a flexible footbridge subject to crowd loading is examined in this paper. Typically, bridge vibrations produced from a crowd of pedestrians are estimated by using an enhancement factor applied to the effect caused by a single pedestrian. In this paper, a single pedestrian model, represented by a spring mass damper, which incorporates variables such as pedestrian mass and body stiffness, is used to calibrate a computationally efficient moving force model. This calibrated moving force model is further used in Monte Carlo simulations of non-homogenous crowds to estimate characteristic vertical vibration levels. Enhancement factors, which could be applied to simple single pedestrian moving force models in estimating the response due to a crowd are thus derived. Such enhancement factors are then compared to previously published values. It is found that the greatest difference between the spring mass damper and moving force models respectively occurs when the bridge frequency is at the mean crowd pacing frequency. For bridges with frequencies even slightly removed from this mean, moving force models appear adequate.
Reusable learning objects may be considered to be pre-developed digital learning activities that ... more Reusable learning objects may be considered to be pre-developed digital learning activities that may be integrated into lessons, modules, and courses. Their advantages include their flexibility of content, their accessibility and the possibilities of using them as a means of evaluation. The aim of this project was to develop such an object for use in teaching structural engineering. A review of best practice in development of reusable learning objects was conducted, followed by a suitability analysis of various software packages available for use in the development of the resource. A reusable learning object to be used in the teaching of the principle of second moment of area was developed. This interactive resource was made accessible through a virtual learning environment (Moodle) and accessed by students from engineering and non-engineering programmes in both AIT and GMIT, who provided feedback on the object via an online survey.