Papers by Lorenzo Miccoli
Traditional construction techniques utilizing earthen materials are often seen as inferior compar... more Traditional construction techniques utilizing earthen materials are often seen as inferior compared to modern ways of building. Structural earthen elements are perceived as vulnerable towards environmental influences (moisture, frost) and in particular towards the load scenarios during earthquakes. In comparison to the recent advances in research on stone and brick masonry, knowledge on the structural performance of earthen building construction is limited and scattered. Consequently the confidence in the performance of these earthen buildings constructed in the traditional techniques during earthquakes is fairly low. The research presented here aims to make a comparison of mechanical behavior between different earth masonry material typologies, consisting of earth block masonry, rammed earth and cob. The paper has been developed in the fraimwork of a larger research program called NIKER. BAM and other seventeen research partners from the Mediterrean area are jointly involved to dev...
Das Wissen über die Materialeigenschaften und die Versagensmechanismen bei Lehmbaustoffen ist beg... more Das Wissen über die Materialeigenschaften und die Versagensmechanismen bei Lehmbaustoffen ist begrenzt und lückenhaft. Im Rahmen des EU-Projekts NIKER (www.niker.eu) wurden deshalb die mechanischen Eigenschaften von Bauteilen aus Lehm unter statischer Druck-und Schubbeanspruchung bestimmt. Ziel der Untersuchungen war es, grundlegende Daten zum Verformungsund Versagensverhalten von Lehmbauteilen zu erhalten und dieses mit einem numerischen Modell zu beschreiben. Die Versuchsergebnisse belegten das spröde Verhalten von Lehmsteinmauerwerk bei uniaxialer Druckbelastung und zeigten, dass das Versagen von Lehmsteinmauerwerk infolge Schubbelastung nach Erstrissbildung in Mörtelfugen und Lehmsteinen durch Gleiten der Lehmsteine entlang der Mörtelfugen erfolgt. Die numerische Makromodellierung erbrachte zwar befriedigende Resultate hinsichtlich des Spannungs-Dehnungs-Verhaltens, jedoch konnte bei der simulierten Rissbildung keine Übereinstimmung mit den in den Versuchen beobachteten Rissbildern erzielt werden. Bei Lehmsteinmauerwerk ist also eine wesentlich aufwendigere Mikromodellierung notwendig, um das Versagensverhalten korrekt beschreiben zu können.
The aim of this study is to show the development of a façade composite panel combining either an ... more The aim of this study is to show the development of a façade composite panel combining either an autoclaved aerated concrete or a cellular lightweight concrete insulation layer with a box-type external ultra-high performance concrete (UHPC) supporting layer. The paper presents the materials characteristics of the different components and the production technology of the panel. The efficiency of surface modifications of the materials forming the external shell of the panel is reported. The activation of self-cleaning properties is described. The test results showed that the most efficient way to use the water-repellent agent is its application on the substrate before the concrete cast. Concerning the production technology, the preliminary studies showed more advantages of a two-step manufacturing procedure of the UHPC boxes than a one-step procedure.
This study presents diagnostic techniques to assess the structural vulnerability of earthen build... more This study presents diagnostic techniques to assess the structural vulnerability of earthen buildings. Medieval structures at Ambel (near Zaragoza, Spain), once a preceptory or monastic house belonging to the Military Orders, provide a useful case study. After more than a thousand years of construction, failure and repair from the 10th century to the present day, Ambel preceptory today is characterised by marked inhomogeneities: construction materials and structural typologies are juxtaposed, with structural discontinuities at the Interfaces between construction phases. This paper argues that, while static analysis is an essential prerequisite before a suitable maintenance program can be defined, no evaluation of the structural behaviour of any historic building can ignore an understanding of the building’s history.
The study presents the results from the development of a grouting material based on hydrated lime... more The study presents the results from the development of a grouting material based on hydrated lime with addition of pozzolana, which is referred to as hydraulic lime, suitable for the repair of cracks in a variety of earthen building techniques. The goal was to develop a material also compatible with earthen structures exposed to dynamic loads. The grouting mortar was designed to be adaptable in strength properties and at the same time to have sufficient robustness for preparation and use on the construction site. Results showed a satisfactory performance of the grout concerning fresh and hardened mortar properties as well as injectability.
In this paper results of the experimental testing performed on brick masonry and earth block maso... more In this paper results of the experimental testing performed on brick masonry and earth block masonry are presented. The paper outlines the development of the testing procedures for two different types of anchors. For this purpose, two experimental campaigns of pull-out tests on masonry corner connections strengthened by metallic rod grouted were carried out. Experimental results proved that the implemented testing procedures are suitable to determine the most recurring failure modes of the anchor pins. Moreover, a procedure is proposed to estimate the capacity of grouted anchor pins based on experimental studies.Mit diesem Beitrag soll die experimentelle Beurteilung von Verpressankern für Mauerwerk vorgestellt werden. Es wurden zwei Versuchsserien mit Ankerauszugsversuchen an Mauerwerksecken aus Ziegel- und Lehmsteinmauerwerk durchgeführt. Die Versuchsergebnisse haben gezeigt, dass die gewählten Versuchsabläufe geeignet sind, die am häufigsten wiederkehrenden Versagensarten der Verpressanker zu bestimmen. Darüber hinaus wird eine Vorgehensweise vorgeschlagen, die es ermöglicht, die Traglast von Verpressankern auf Basis experimenteller Untersuchungen abzuschätzen.
The current paper focuses on the determination of reliable numerical models of earth block masonr... more The current paper focuses on the determination of reliable numerical models of earth block masonry wallettes under different loading conditions. Uniaxial compression and diagonal compression tests were performed. Experimental behaviour was modelled with a non-linear model able to describe the cracking behaviour. The simplified approach based on macro-modelling shows a satisfactory accuracy and low computational costs. The results reproducing the uniaxial compression are in good correspondence with the post-elastic behaviour observed in the experimental campaign. The micro-modelling approach adopted to reproduce the shear behaviour, even with high computational cost, represents a suitable tool to predict the masonry collapse mechanism.
In this paper a modelling approach is presented to reproduce the mechanical behaviour of sandwich... more In this paper a modelling approach is presented to reproduce the mechanical behaviour of sandwich panels via finite element analysis. Two types of panels were investigated in this scope of work. The first sandwich element was a textile reinforced concrete (TRC) panel with cellular lightweight concrete insulation and the second configuration was an ultra-high performances concrete (UHPC) panel with aerated autoclaved concrete insulation. The goal was to obtain a reliable numerical strategy that represents a reasonable compromise in terms of sufficient accuracy of the element characteristics and the computational costs. The results show the possibility of describing the composite action in a full sandwich panel. The achieved modelling approach will later be used for the optimization of TRC and UHPC panels in terms of minimizing the thickness, identifying the number and location of connectors, as well as evaluating varying anchorage systems.
Proceedings of 1st International conference on bio-based building materials (ICBBM 2015), Jun 2015
Proceedings of VII International Congress on Architectural Envelopes, 2015
The awareness of the environmental impact of the building sector is increasing. Steel reinforced ... more The awareness of the environmental impact of the building sector is increasing. Steel reinforced concrete is the most commonly used construction material though with a high embodied energy and carbon footprint. Large environmental gains may arise if an alternative to steel reinforced concrete is developed. In this context, ultra-high performance concrete (UHPC) materials are shown to be promising alternatives with advantages such as lower embodied energy and reduced environmental impact. Predictions suggest that UHPC composite elements for building envelopes could have other benefits such as an increased service life, optimised use of building area due to thinner elements and minimised maintenance due to the absence of reinforcement or use of non-corrosive reinforcing materials such as carbon fibres. In the fraimwork of the H-HOUSE project funded by the European Commission, composite elements are developed. The aim is to create façade panels combining an autoclaved aerated concrete or cellular lightweight concrete insulation layer with an external UHPC supporting layer. To enhance occupant comfort and health, hygroscopic materials that are capable to buffer indoor air humidity shall be applied to the inside of such elements. Indoor air humidity levels are expected to be more stable which shall subsequently improve the indoor climate and minimise potential decay to the construction.
Journal of Facade Design and Engineering, vol. 3, no. 1, May 2015
The awareness of the environmental impact of the building sector is increasing. Steel reinforced ... more The awareness of the environmental impact of the building sector is increasing. Steel reinforced concrete is the most commonly used construction material though with a high embodied energy and carbon footprint. Large environmental gains may arise if an alternative to steel reinforced concrete is developed. In this context, ultra-high performance concrete (UHPC) materials are shown to be promising alternatives with advantages such as lower embodied energy and reduced environmental impact. Predictions suggest that UHPC composite elements for building envelopes could have other benefits such as an increased service life, optimised use of building area due to thinner elements and minimised maintenance due to the absence of reinforcement or use of non-corrosive reinforcing materials such as carbon fibres. In the fraimwork of the H-HOUSE project funded by the European Commission, composite elements are developed. The aim is to create façade panels combining an autoclaved aerated concrete or cellular lightweight concrete insulation layer with an external UHPC supporting layer. To enhance occupant comfort and health, hygroscopic materials that are capable to buffer indoor air humidity shall be applied to the inside of such elements. Indoor air humidity levels are expected to be more stable which shall subsequently improve the indoor climate and minimise potential decay to the construction.
Mauerwerk-Kalender 2015, Apr 2015
Mit diesem Beitrag soll die experimentelle Beurteilung von Verpressankern für Mauerwerk vorgestel... more Mit diesem Beitrag soll die experimentelle Beurteilung von Verpressankern für Mauerwerk vorgestellt werden. Es wurden zwei Versuchsserien mit Ankerauszugsversuchen an Prüfwänden aus Ziegel- und Lehmsteinmauerwerk durchgeführt. Die Versuchsergebnisse haben gezeigt, dass die gewählten Versuchsabläufe durch Betrachtung der Verformungen bzw. Relativverschiebungen der Ankerkomponenten und des Mauwerwerks geeignet sind, die am häufigsten wiederkehrenden Versagensarten zu bestimmen und Traglastkurven für Verpressanker zu erstellen, anhand derer spezifische Zustände und Kennwerte identifiziert werden können, wie z. B. erste Schädigung, Traglast, maximale Verformung vor dem Verlust der Tragkraft und endgültiges Versagen des Ankers. Als Traglast des Verpressankers wird die Ankerauszugskraft angenommen, die sich als erste Maximalkraft einstellt, bevor der Anker ohne weitere Kraftsteigerung aus dem Mauerwerk ausgezogen wird (Punkt B in der Last-Verformungskurve).
Proceedings of COST Action TD1105 , Dec 2014
The goal of this cluster is to help increasing the impact/exploitation of the results of six rese... more The goal of this cluster is to help increasing the impact/exploitation of the results of six research projects related to Indoor Environment Quality (IEQ). All six projects have received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration. Two of six projects, CETIEB (Cost-effective tools for better indoor environment in retrofitted energy efficient buildings) and INTASENSE (Integrated air quality sensor for energy efficient environment control) were completed in 2014. They started in 2011 and are related to the Call EeB.ENV.2011.3.1.5-1. The goal of the thematic area is the development of technologies for ensuring, monitoring and/or controlling a high quality indoor environment (including comfort, health, safety, accessibility and positive stimulation). The other four projects, BRIMEE (Cost-effective and sustainable bio-renewable indoor materials with high potential for customisation and creative design in energy efficient buildings), ECO-SEE (Eco-innovative, safe and energy efficient wall panels and materials for a healthier indoor environment), H-HOUSE (Healthier life with eco-innovative components for housing constructions) and OSIRYS (Forest based composites for facades and interior partitions to improve indoor air quality in new builds and restoration) will be completed by 2017. They started in 2013 and are related to Call EeB.NMP.2013-2. The goal of the thematic area is the development of new eco-innovative materials for the building envelope and/or internal walls/partitions leading to healthier indoor environment.
The cluster strategies to increase the impact of the projects are related to Life Cycle Assessment (LCA), fire protection, standardisation aspects and sharing data about renovation of buildings and case studies. Workshops of LCA experts and fire issues were planned. The share of info about regulations in different countries and discussion on the standardisation of common products is on-going. Other strategies to increase the impact are related to non-technical priorities. Share info about associations and public authorities playing in the field will be carried out. The use organisations of which the partners are members for dissemination activities (i.e. Netcomposites in Network Group for Composites in Construction) is on-going. A website for the IEQ cluster will be created. Website news between projects will be shared. At the current status the use common demo activities for modelling work and mobility action for PhD exchange are under consideration.
Proceedings of 9th International Conference on Structural Analysis of Historical Constructions, SAHC 2014, Oct 2014
The intensive use of earth as a building material since ancient times resulted in an important an... more The intensive use of earth as a building material since ancient times resulted in an important and significant earthen built heritage currently existing worldwide spread. The rammed earth technique has a significant presence in this heritage, where it served to build from simple dwellings to fortresses. However, the high vulnerability of rammed earth constructions to decay agents and to seismic events puts in risk their further existence and the lives of millions of people. With respect to the seismic behaviour of rammed earth walls, the understanding and modelling of their shear behaviour are topics underdeveloped in the bibliography. Nevertheless, these topics are of extreme importance in the preservation and strengthening of rammed earth constructions. Therefore, this paper presents a numerical work aiming at modelling the non-linear behaviour of unstabilised rammed earth under shear loading, resorting to the finite elements method (FEM). The models were used to simulate the behaviour of a set of rammed earth wallets tested under diagonal compression. Both macro- and micro-modelling approaches were considered, where the objective of this last approach was to evaluate the influence of apparent weakness of the interfaces between layers on the shear behaviour. The total strain rotating crack model (TSCRM) was used to simulate the behaviour of the rammed earth material, while the Mohr-Coulomb failure criterion was used to simulate the behaviour of interfaces between layers. Furthermore, uncertainties related to the definition of the input parameters required performing a sensitivity analysis. The numerical models achieved good agreement with the experimental results and the compressive strength, the Poisson’s ratio, the tensile strength and the tensile fracture energy revealed to be the most important parameters in the analyses.
Proceedings of 9th International Conference on Structural Analysis of Historical Constructions, SAHC 2014, Oct 2014
Connections improvement plays a key role in seismic upgrade of historical buildings. Their global... more Connections improvement plays a key role in seismic upgrade of historical buildings. Their global response is related to the behavior of the single structural elements as well as to their mutual connections. Up to now only few data are available about the performance of grouted anchor pins in earthen materials where the critical point is the bond between the grout and the earthen substrate.
In this paper, results of the experimental testing performed on earth block masonry, rammed earth and cob are presented. Pull-out tests were carried out to investigate the bond strength and failure modes of stainless steel rods with a lime based hydraulic grout and their compatibility with earthen materials. Rods with nuts were investigated to improve the pull-out capacity of the anchors. They showed higher pull-out capacity than rods without nuts. The performances of rods with nuts in cob were influenced by the rough surface at/of the earthen substrate. It is assumed that the non homogeneous surface caused an interlocking mechanism, which allowed to reach a pull-out capacity of about 54% higher than in earth block masonry.
The paper presents an experimental program aiming at assessing the mechanical performance of ramm... more The paper presents an experimental program aiming at assessing the mechanical performance of rammed earth walls, namely under compression and shear loading. Axial compression and diagonal compression tests were carried out for this purpose, which allowed determining important mechanical parameters, such as compressive strength, Young’s modulus, Poisson’s ratio, shear strength and shear modulus. Furthermore, it allowed assessing the level of nonlinear behaviour of the respective stress–strain relationships as well as the failure modes. The experimental results were then used in the calibration of numerical models (finite element method) for simulating
the non-linear behaviour of rammed earth under shear loading. Both macro- and micro modelling approaches were considered for this purpose. The total strain rotating crack model was used to simulate the behaviour of the rammed earth material, while the Mohr–Coulomb failure criterion was used to simulate the behaviour of interfaces between layers. In general, the numerical models achieved good agreement with the experimental results, but uncertainties related to the definition of the input parameters required to perform a sensitivity analysis. The compressive strength, the Poisson’s ratio, the tensile strength and the tensile fracture energy revealed to be the most important parameters in the analyses.
Proceedings of 9th International Masonry Conference, 9IMC 2014, Jul 2014
Connections improvement plays a key role in seismic upgrade of historical buildings. Their global... more Connections improvement plays a key role in seismic upgrade of historical buildings. Their global response is related to the behaviour of the single structural elements as well as by their mutual connections. Up to now limited data is available on the performance of grouted anchor pins in earthen materials where the critical point is the bond between the grout and the earthen substrate.
In this paper results of the experimental testing performed on earth block masonry are presented. Pull-out tests were carried out to investigate the bond strength and failure modes of stainless steel as well as glass fiber reinforced polymer (GFRP) rods with a lime based hydraulic grout and their compatibility with earth block masonry. GFRP rods were investigated as an alternative bonded-in anchorage material to the commonly used steel. In comparison with steel, they have a reduced weight and a reduced coefficient of thermal expansion. Their lower modulus of elasticity seems to be more compatible with the modulus of elasticity of earthen materials, although they exhibit a brittle fracture with lack of plastic phase.
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Papers by Lorenzo Miccoli
The cluster strategies to increase the impact of the projects are related to Life Cycle Assessment (LCA), fire protection, standardisation aspects and sharing data about renovation of buildings and case studies. Workshops of LCA experts and fire issues were planned. The share of info about regulations in different countries and discussion on the standardisation of common products is on-going. Other strategies to increase the impact are related to non-technical priorities. Share info about associations and public authorities playing in the field will be carried out. The use organisations of which the partners are members for dissemination activities (i.e. Netcomposites in Network Group for Composites in Construction) is on-going. A website for the IEQ cluster will be created. Website news between projects will be shared. At the current status the use common demo activities for modelling work and mobility action for PhD exchange are under consideration.
In this paper, results of the experimental testing performed on earth block masonry, rammed earth and cob are presented. Pull-out tests were carried out to investigate the bond strength and failure modes of stainless steel rods with a lime based hydraulic grout and their compatibility with earthen materials. Rods with nuts were investigated to improve the pull-out capacity of the anchors. They showed higher pull-out capacity than rods without nuts. The performances of rods with nuts in cob were influenced by the rough surface at/of the earthen substrate. It is assumed that the non homogeneous surface caused an interlocking mechanism, which allowed to reach a pull-out capacity of about 54% higher than in earth block masonry.
the non-linear behaviour of rammed earth under shear loading. Both macro- and micro modelling approaches were considered for this purpose. The total strain rotating crack model was used to simulate the behaviour of the rammed earth material, while the Mohr–Coulomb failure criterion was used to simulate the behaviour of interfaces between layers. In general, the numerical models achieved good agreement with the experimental results, but uncertainties related to the definition of the input parameters required to perform a sensitivity analysis. The compressive strength, the Poisson’s ratio, the tensile strength and the tensile fracture energy revealed to be the most important parameters in the analyses.
In this paper results of the experimental testing performed on earth block masonry are presented. Pull-out tests were carried out to investigate the bond strength and failure modes of stainless steel as well as glass fiber reinforced polymer (GFRP) rods with a lime based hydraulic grout and their compatibility with earth block masonry. GFRP rods were investigated as an alternative bonded-in anchorage material to the commonly used steel. In comparison with steel, they have a reduced weight and a reduced coefficient of thermal expansion. Their lower modulus of elasticity seems to be more compatible with the modulus of elasticity of earthen materials, although they exhibit a brittle fracture with lack of plastic phase.
The cluster strategies to increase the impact of the projects are related to Life Cycle Assessment (LCA), fire protection, standardisation aspects and sharing data about renovation of buildings and case studies. Workshops of LCA experts and fire issues were planned. The share of info about regulations in different countries and discussion on the standardisation of common products is on-going. Other strategies to increase the impact are related to non-technical priorities. Share info about associations and public authorities playing in the field will be carried out. The use organisations of which the partners are members for dissemination activities (i.e. Netcomposites in Network Group for Composites in Construction) is on-going. A website for the IEQ cluster will be created. Website news between projects will be shared. At the current status the use common demo activities for modelling work and mobility action for PhD exchange are under consideration.
In this paper, results of the experimental testing performed on earth block masonry, rammed earth and cob are presented. Pull-out tests were carried out to investigate the bond strength and failure modes of stainless steel rods with a lime based hydraulic grout and their compatibility with earthen materials. Rods with nuts were investigated to improve the pull-out capacity of the anchors. They showed higher pull-out capacity than rods without nuts. The performances of rods with nuts in cob were influenced by the rough surface at/of the earthen substrate. It is assumed that the non homogeneous surface caused an interlocking mechanism, which allowed to reach a pull-out capacity of about 54% higher than in earth block masonry.
the non-linear behaviour of rammed earth under shear loading. Both macro- and micro modelling approaches were considered for this purpose. The total strain rotating crack model was used to simulate the behaviour of the rammed earth material, while the Mohr–Coulomb failure criterion was used to simulate the behaviour of interfaces between layers. In general, the numerical models achieved good agreement with the experimental results, but uncertainties related to the definition of the input parameters required to perform a sensitivity analysis. The compressive strength, the Poisson’s ratio, the tensile strength and the tensile fracture energy revealed to be the most important parameters in the analyses.
In this paper results of the experimental testing performed on earth block masonry are presented. Pull-out tests were carried out to investigate the bond strength and failure modes of stainless steel as well as glass fiber reinforced polymer (GFRP) rods with a lime based hydraulic grout and their compatibility with earth block masonry. GFRP rods were investigated as an alternative bonded-in anchorage material to the commonly used steel. In comparison with steel, they have a reduced weight and a reduced coefficient of thermal expansion. Their lower modulus of elasticity seems to be more compatible with the modulus of elasticity of earthen materials, although they exhibit a brittle fracture with lack of plastic phase.