Infrastructure Engineering - Research Publications

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    Multi-Criteria Analysis of a Developed Prefabricated Footing System on Reactive Soil Foundation
    Teodosio, B ; Bonacci, F ; Seo, S ; Baduge, KSK ; Mendis, P (MDPI, 2021-11-01)
    The need for advancements in residential construction and the hazard induced by the shrink–swell reactive soil movement prompted the development of the prefabricated footing system of this study, which was assessed and compared to a conventional waffle raft using a multi-criteria analysis. The assessment evaluates the structural performance, cost efficiency, and sustainability using finite element modelling, life cycle cost analysis, and life cycle assessment, respectively. The structural performance of the developed prefabricated system was found to have reduced the deformation and cracking by approximately 40%. However, the cost, GHG emission, and embodied energy were higher in the prefabricated footing system due to the greater required amount of concrete and steel than that of the waffle raft. The cost difference between the two systems can be reduced to as low as 6% when prefabricated systems were installed in a highly reactive sites with large floor areas. The life cycle assessment further observed that the prefabricated footing systems consume up to 21% more energy and up to 18% more GHG emissions. These can significantly be compensated by reusing the developed prefabricated footing system, decreasing the GHG emission and energy consumption by 75–77% and 55–59% with respect to that of the waffle raft.
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    Design of prefabricated footing connection using a coupled hydro-mechanical finite element model
    Teodosio, B ; Baduge, KSK ; Mendis, P (ERNST & SOHN, 2021-11-23)
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    Design and Development of Weatherproof Seals for Prefabricated Construction: A Methodological Approach
    Orlowski, K ; Shanaka, K ; Mendis, P (MDPI, 2018-09-01)
    Satisfactory weatherproofing of buildings is vital to maximise their design life and performance which requires the careful design of external sealing technologies. Systems commonly available have served well in conventional construction however with many prefabricated systems emerging in the building industry new and novel means of weatherproofing between panels and modules need to be developed purpose specific to this application. This paper presents a holistic and fundamental methodological approach to Design and Development of waterproof seals and has been applied specific for prefabricated panelised and modular systems. Two purpose specific weatherproof seals are finally presented. Flow charts of the overview of the suggested methodological approach and the processes within which include DfMA that have been incorporated into understanding and developing seals for this practical application. These strategies have enabled a resourceful and holistic set of processes that can be adapted and used for similar forms of product research in new and developing areas of construction such as prefabrication. The design and development process is thoroughly investigated and has resulted in an exploration of the technical challenges and potential solutions which take into consideration factors from installation limitations to building tolerances.
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    Aggregate Geometry Generation Method Using a Structured Light 3D Scanner, Spherical Harmonics-Based Geometry Reconstruction, and Placing Algorithms for Mesoscale Modeling of Concrete
    Thilakarathna, PSM ; Kristombu Baduge, S ; Mendis, P ; Chandrathilaka, ERK ; Vimonsatit, V ; Lee, H (American Society of Civil Engineers, 2021-08-01)
    Mesoscale numerical modeling is an effective method of representing concrete as a three-phase material. Accurate aggregate geometry representation is an important aspect in numerical mesoscale modeling of concrete to predict mechanical properties as well as the damage initiation and fracture propagation. In this paper, a novel approach of three-dimensional (3D) scanning of aggregates using a structured light 3D scanner is presented, and parametric geometry reconstruction of aggregate geometries using spherical harmonics is carried out. This novel method of scanning aggregates is a faster, safer, economical, and convenient method of obtaining the 3D geometry compared with other methods. A comprehensive database of aggregate geometries is developed, and an innovative aggregate-placing algorithm for these aggregates is presented to develop the mesostructure. In addition to the proposed geometry generation method, a novel parametric-based geometry generation and distribution method for polyhedral aggregate shapes is presented, including flaky and elongated particles. Finally, aggregate transferring methods to finite-element software and mesh generation methods are discussed with the challenges and possible methods to overcome these issues.
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    A review and comparison of design methods for raft substructures on expansive soils
    Teodosio, B ; Kristombu Baduge, KS ; Mendis, P (Elsevier, 2021-09-01)
    Shrink-swell movements of soils cause angular distortion to substructures leading to significant damage to lightweight structures. The built environment of lightweight structures, particularly single-detached dwellings, may compromise the structural performance and cause unforeseen maintenance that may expedite the deterioration of an entire build. Due to the importance of damage minimisation in the design phase of single-detached dwellings, this paper aims to review and compare existing design methods for raft substructures on expansive soils through parametric comparison. The comparison considered parameters related to soil properties, environmental factors and stress conditions, including substructure configuration, affecting the shrink-swell potential of expansive soils. The comparison observed that PTI method calculated beam depths with most proximate values to the overall median, while Lytton and Briaud method calculated beam depths closest to the overall third quartile with respect to all considered design methods. WRI and BRAB method obtained larger values of beam depths, specifically for scenarios with higher plasticity index, liquid limit and longer span, which can be considered as outliers. AS 2870, Walsh and Mitchell method were in the less conservative range based on the range of beam depths calculated. Calculated required beam depths ranged from 300 to 815 mm neglecting outliers with higher dispersion of values when the active depth zone was deeper, the plasticity index and liquid limit were higher, applied uniform load was higher and span of the substructure was longer. This review paper presents the range of probable values, variability and degree of central tendency depending on the values of beam depths calculated by different current design methods that are useful for designers.
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    Flexural Performance of Prefabricated Ultra-High-Strength Textile Reinforced Concrete (UHSTRC): An Experimental and Analytical Investigation
    Chandrathilaka, ERK ; Baduge, SK ; Mendis, P ; Thilakarathna, PSM (MDPI AG, 2020-04-02)
    Textile Reinforced Concrete (TRC) is a prefabricated novel lightweight high-performance composite material that can be used as a load-bearing or non-load-bearing component of prefabricated buildings. Making TRC with Ultra-High-Strength Concrete (UHSC) (≥100 MPa) can be considered as a potential improvement method to further enhance its properties. This paper investigated the performance of Ultra-High-Strength Textile Reinforced Concrete (UHSTRC) under flexural loading. A detailed experimental program was conducted to investigate the behavior of UHSC on TRC. In the experimental program, a sudden drop in load was observed when the first crack appeared in the UHSTRC. A detailed analytical program was developed to describe and understand such behavior of UHSTRC found in experiments. The analytical program was found to be in good agreement with the experimental results and it was used to carry out an extensive parametric study covering the effects of the number of textile layers, textile material, textile mesh density, and UHSTRC thickness on the performance of UHSTRC. Using a high number of textile layers in thin UHSTRC was found to be more effective than using high-thickness UHSTRC. The high modulus textile layers effectively increase the performance of UHSTRC.
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    Prefabrication of substructures for single-detached dwellings on reactive soils: a review of existing systems and design challenges
    Teodosio, B ; Baduge, KSK ; Mendis, P ; Heath, DJ (Taylor & Francis, 2019-08-27)
    The possible thriving Australian construction industry for residential structures has been hindered by skilled labour shortage and eventually triggered housing shortage and affordability crisis. Prefabrication is a promising method to alleviate issues related to housing shortage and affordability by reducing material wastage, construction delays, weather impacts, unexpected costs, skilled labour dependence and construction risks. The full potential of prefabricated construction is yet to be realised in part due to most of developments being focused on its superstructure. Prefabricated substructures should conform with the Ultimate Limit State (i.e. strength capacity) and the Serviceability Limit State (i.e. allowable deformation and damage) stated in the Australian Standards. Due to the initiatives to alleviate issues of housing crisis, skilled labour shortage and unpredictable house damage, it is necessary to review the existing available substructures suitable for single-detached dwellings on reactive soils and to evaluate the necessary considerations and challenges in developing prefabricated substructures. This review will help understand the present state of the design and construction industry and the efforts of inventors and designers to reduce damages due to the shrinking and swelling ground movements. This review also guides product developers to design systems having robust performance without compromising practicality.
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    Performance of lightweight hemp concrete with alkali-activated cenosphere binders exposed to elevated temperature
    Kristombu Baduge, S ; Mendis, P ; San Nicolas, R ; Nguyen, K ; Hajimohammadi, A (Elsevier BV, 2019-11-10)
    This study investigates the performance of three different types of cenosphere as a lightweight supplementary cementitious material for alkali-activated binder for lightweight carbon-negative hemp-concrete for non-load bearing applications. Mechanical performance of hemp concrete exposed to three temperatures, room temperature (RT), 300 °C and 600 °C are studied using mechanical testing, thermogravimetric analysis (TGA) and Fourier-transform Infrared Spectroscopy (FTIR). Hemp concrete with cenosphere binder remained its integrity and showed a lower load carrying capacity even after exposure to elevated temperatures. Compressive strength capacity and elastic modulus of the samples reduced with the increase of temperature and shows the composite material is more suitable for non-load bearing application considering its mechanical behavior and fire requirements. The density, age, and type of cenosphere showed effects on mechanical properties at room temperature and elevated temperatures. The study shows that alkali activated cenosphere binders can potentially be a sustainable alternative to the lime binder.
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    Cohesive-strength homogenisation model of porous and non-porous materials using linear comparison composites and application.
    Lee, H ; Vimonsatit, V ; Huen, WY ; Mendis, P ; Baduge, KSK (Nature Publishing Group, 2020-02-25)
    An estimation of the strength of composite materials with different strength behaviours of the matrix and inclusion is of great interest in science and engineering disciplines. Linear comparison composite (LCC) is an approach introduced for estimating the macroscopic strength of matrix-inclusion composites. The LCC approach has however not been expanded to model non-porous composites. Therefore, this paper is to fill this gap by developing a cohesive-strength method for modelling frictional composite materials, which can be porous and non-porous, using the LCC approach. The developed cohesive-strength homogenisation model represents the matrix and inclusion as a two-phase composite containing solids and pores. The model is then implemented in a multiscaling model in which porous cohesive-frictional solids intermix with each other at different scale levels classified as micro, meso and macro. The developed model satisfies an upscaling scheme and is suitable for investigating the effects of the microstructure, the composition, and the interface condition of the materials at micro scales on the macroscopic strength of the composites. To further demonstrate the application of the developed cohesive-strength homogenisation model, the cohesive-strength properties of very high strength concrete are determined using instrumented indentation, nonlinear limit analysis and second-order cone programming to obtain material properties at different scale levels.
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    Structural behaviour of prefabricated stressed-skin engineered timber composite flooring systems
    Orlowski, K ; Baduge, SK ; Mendis, P ; Oktavianus, Y (Elsevier, 2019-12-01)
    The primary focus of this study is understanding the behaviour and structural performance of prefabricated composite timber floor cassette systems with Oriented strand board (OSB) stressed-skins. These do not have a dedicated top flange, instead their plywood webs are integrally bonded to the OSB flooring skin through a chemical connection. Subsequently, local buckling of the stressed-skin was found to occur as the first failure mode. Specimens with 150 mm and 300 mm nail spacings were investigated for its effects on performance due to the criticality of the integrated web to floor skin connection in these systems. A total of 20 stressed-skin specimens were tested in three-point bending with recordings of the applied force, displacement, slip and failure modes. It was found that local buckling of the skin is prone to occur prior to reaching the designed SLS limit. A detailed Finite Element Analysis (FEA) which takes into consideration the full behaviour of the materials and the glue and nail connections along with failure modes has been validated and used to provide insight to potential design solutions. Key parameters investigated include the adhesive properties, the ratio of clear effective outstand width of the flange to the thickness of the stressed-skin (beff,o/t), ratio of the clear depth of the web to the thickness of the web (dp/tw), ratio of the clear span to the total depth of the composite beam (Lc/D) and finally the spacing of the nails. This has resulted in a broad level understanding of the effects of these design parameters to the behaviour of stressed-skin engineered timber flooring cassettes.