The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Ezio Giuriani - One of the best experts on this subject based on the ideXlab platform.
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improved natural hydraulic lime mortar slab for compatible retrofit of Wooden Floors in historical buildings
Construction and Building Materials, 2018Co-Authors: Alessandra Marini, Stefania Cominelli, Cristina Zanotti, Ezio GiurianiAbstract:Abstract Stiffening of Wooden Floors is often required in the rehabilitation of historical buildings to reduce their deformability in service conditions. Among various techniques available in the literature, the application of an extrados reinforced concrete overlay is often selected because cost/structurally effective and relatively simple to place. Nevertheless, Ordinary Portland Cement (OPC) concrete is considered poorly compatible with historical structures and materials and is, therefore, not well received, especially in case of valuable heritage and monumental constructions. A new retrofit solution based on the replacement of OPC with improved natural hydraulic lime (NHL) is proposed. Like the traditional OPC concrete overlay, the novel solution with improved NHL allows the conservation of the existing planks, and, thus, preserves the integrity of the Wooden ceiling. The structural effectiveness of the proposed technique is investigated through experimental tests on full scale beams with different geometries. Full scale tests are supported by material tests and tests on the wood-mortar stud connection, a key aspect of the beam design. Based on the literature in the field of OPC concrete-wood composites, analytical models are developed and applied to predict the behavior of the NHL mortar-wood stud connection and composite beams. Results in terms of both stiffness and strength are encouraging and set the path for the application of NHL mortar overlays in the rehabilitation of heritage Wooden Floors.
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On the delamination phenomenon in the repair of timber beams with steel plates
Construction and Building Materials, 2016Co-Authors: Giovanni Metelli, Marco Preti, Ezio GiurianiAbstract:Abstract This paper presents a non-invasive technique for the repair of ancient Wooden Floors. Steel plates are glued on one side only by epoxy-adhesive into longitudinal grooves in order to allow the free swelling and shrinkage of the wood in the direction transversal to the plate glueing surface, thus reducing the risk of plate delamination. A set of high strength steel nails provides load transmission from the steel plates to the Wooden beam in the case of loss of adhesion due to fire or delamination. This technique was used to repair a precious beam in a 15th-century Wooden floor in Palazzo Calini (Brescia, Italy). The technique requires particular attention because it might be affected by the delamination of the glued reinforcement due to stress concentration, which occurs at the end of the repairing element or at any cracks in the repaired beam. Results of experimental studies on delamination phenomenon investigated by means of the Moire interferometry analysis are also presented. These show that the risk of plate debonding can be markedly reduced by the capability of the sapwood to develop plastic strain. The Wooden floor has been monitored for more than fourteen years, confirming the effectiveness of the adopted technique.
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The Repair of Timber Beams with Controlled-Debonding Steel Plates
Advanced Materials Research, 2013Co-Authors: Giovanni Metelli, Ezio Giuriani, Egidio MarchinaAbstract:In this paper a non-invasive technique for the repair of ancient Wooden Floors is presented. Steel plates are glued on one side only by epoxy-adhesive into longitudinal grooves in order to allow the free swelling and shrinkage of the wood in the direction transversal to the plate glueing surface, thus reducing the risk of plates’ delamination. A set of high strength steel nails guarantees the transmission of the load from the steel plates to the Wooden beam in case of loss of adhesion due to fire or delamination. This technique was used to repair a precious beam in a Wooden floor of the 15th century in Palazzo Calini (Brescia, Italy). The presented technique requires particular attention because it might be affected by the delamination of the glued reinforcement due to the stress concentration, which occurs at the end of the repairing element or at the cracks of the repaired beam.The main results of experimental and numerical studies focusing on the delamination phenomenon are also presented and discussed. They have shown that the risk of plate debonding can be markedly reduced by the capability of the sapwood to develop plastic strain. The Wooden floor has been monitored for more than eleven years, confirming the effectiveness of the adopted technique. The monitoring has also shownthe importance of limiting the Wooden moisture content variation to reduce the floor’s creep deflection.
Polona Weiss - One of the best experts on this subject based on the ideXlab platform.
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seismic upgrading of old masonry buildings by seismic isolation and cfrp laminates a shaking table study of reduced scale models
Bulletin of Earthquake Engineering, 2009Co-Authors: Miha Tomaževic, Iztok Klemenc, Polona WeissAbstract:The efficiency of improving the seismic resistance of old masonry buildings by means of seismic isolation and confining the structure with CFRP laminate strips has been investigated. Five models of a simple two-story brick masonry building with Wooden Floors without wall ties have been tested on the shaking table. The control model has been built directly on the foundation slab. The second model has been separated from it by a damp-proof course in the form of a PVC sheet placed in the bed-joint between the second and the third course, whereas the third model has been isolated by rubber isolators placed between the foundation slab and structural walls. Models four and five have been confined with CFRP laminate strips, simulating the wall ties placed horizontally and vertically at floor levels and corners of the building, respectively. One of the CFRP strengthened models has been placed on seismic isolators. Tests have shown that a simple PVC sheet damp-proof course cannot be considered as seismic isolator unless adequately designed. Tests have also shown that the isolators alone did not prevent the separation of the walls. However, both models confined with CFRP strips exhibited significantly improved seismic behavior. The models did not collapse even when subjected to significantly stronger shaking table motion than that resisted by the control model without wall ties.
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Seismic Upgrading of Old Brick‐Masonry Urban Houses: Tying of Walls with Steel Ties
Earthquake Spectra, 1996Co-Authors: Miha Tomaz˘evic˘, Marjana Lutman, Polona WeissAbstract:Abstract The influence of tying the walls with steel ties on the seismic behavior of existing brick‐masonry houses has been investigated. Three models of simple two‐story brick masonry houses with Wooden Floors, with or without wall ties, have been tested on a simple earthquake simulator. In addition, a model with identical structural configuration, but with r.c. slabs instead of Wooden Floors, has been tested for comparison. Whereas Wooden Floors with joists not anchored to the walls did not prevent separation and disintegration of the walls, rigid slabs and steel ties significantly improved seismic behavior. On the basis of test results, a simple method for designing the ties has been proposed.
Alessandra Gubana - One of the best experts on this subject based on the ideXlab platform.
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state of the art report on high reversible timber to timber strengthening interventions on Wooden Floors
Construction and Building Materials, 2015Co-Authors: Alessandra GubanaAbstract:Abstract The goal of this State-of-the-Art-Report (STAR) on high reversible strengthening interventions on timber Floors is to give an overview of the new techniques developed and tested to achieve in-plane and out-of-plane stiffness upgrading by means of less invasive and reversible interventions. In recent years a growing sensibility towards the preservation and maintenance of heritage buildings has led researchers to test different dry retrofitting systems. The report focuses on strengthening interventions based on the use of wood or wood based elements: the most adopted or most promising techniques are so briefly described. While the problem of upgrading the bending stiffness has a solid analytical background in the concrete-to-timber composite section theory, the problem of upgrading the in-plane stiffness still requires attention. The importance of the correct evaluation of the in-plane mechanical properties of floor timber diaphragms is nowadays clearly assessed in order to determine the building structural response under lateral seismic loads. In some codes, simplified analytical procedures are proposed to determine the in-plane stiffness, but generally, with regard to new timber building floor typologies. The tests described in literature are generally referred to different setups, test rigs, boundary conditions, aspect ratio of the floor samples and also the recorded parameters are not always the same ones: it is so difficult to compare the experimental data as to achieve a general stiffness evaluation approach.
Roger Langohr - One of the best experts on this subject based on the ideXlab platform.
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Micromorphological Study of Construction Materials and Living Floors in the Medieval Motte of Werken (West Flanders, Belgium)
Geoarchaeology - An International Journal, 1999Co-Authors: Anne Gebhardt, Roger LangohrAbstract:The "Hoge Andjoen," an early Medieval motte (860-960 CE), is an artificial hill made up of at least eight man-made "ground raising/leveling" layers. Each layer is associated with a stabilization level and a well-preserved occupation surface with evidence such as living Floors, traces of cultivation, and goat/sheep trampling. The presence of this hill generated a local rise in the original groundwater table present in the natural, buried soil of the site. In some parts of the hill, and with little relation to the sedimentary boundaries, this process generated permanent water stagnation with pronounced anaerobic conditions and locally strong gradients of oxidoreduction. These gradients created a series of particular migrations and accumulations of iron, manganese, and phosphorus components. All organic artifacts, such as oak posts, Wooden Floors, leather, and seeds remained well preserved in the strongly reduced parts of the hill; they are completely decayed in the aerated zones of the hill. The soil moisture regime within the motte further influenced a series of postdepositional migrations/accumulations of clay and organic matter. The micromorphological study of this archaeological site allows verification of hypotheses developed during field surveying. These hypotheses relate mainly to the origin and mode of dumping of the various types of earthy material, the human activities related to the nine successive living Floors, and the traces of numerous postdepositional processes observed throughout this archaeological structure.
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Micromorphological Study of Construction Materials and Living Floors in the Medieval Motte of Werken (West Flanders, Belgium)
Geoarchaeology: An International Journal, 1999Co-Authors: Anne Gebhardt, Roger LangohrAbstract:The "Hoge Andjoen," an early medieval motte (860-960 A.D.) is an artificial hill made up of at least eight man-made "ground raising/leveling" layers. Each layer is associated with a stabilization level and a well-preserved occupation surface with evidence such as living Floors, traces of cultivation, and goat/sheep trampling. The presence of this hill generated a local rise in the original groundwater table present in the natural, buried soil of the site. In some parts of the hill, and with little relation to the sedimentary boundaries, this process generated permanent water stagnation with pronounced anaerobic conditions and locally strong gradients of oxidoreduction. These gradients created a series of particular migrations and accumulations of iron, manganese, and phosphorus components. All organic artifacts, such as oak posts, Wooden Floors, leather, and seeds remained well preserved in the strongly reduced parts of the hill; they are completely decayed in the aerated zones of the hill. The soil moisture regime within the motte further influenced a series of postdepositional migrations/accumulations of clay and organic matter. The micromorphological study of this archaeological site allows verification of hypotheses developed during field surveying. These hypotheses relate mainly to the origin and mode of dumping of the various types of earthy material, the human activities related to the nine successive living Floors, and the traces of numerous postdepositional processes observed throughout this archaeological structure. INTRODUCTION The "Hoge Andjoen" Medieval Motte (Werken, West Flanders, Belgium; Figure 1) is a flat artificial hill about 6 m in height and 50 m in base diameter (Figure 2), surrounded by a ditch several meters wide (Figure 3[a]). The site is constructed on the boundary between the occasionally inundated Holocene polder area and the upland with Weichselian coversands resting on a Tertiary sandy to clayey substratum (Figure 1). The archaeological excavation (Vanthournout, 1991) revealed a complex stratigraphy of successive layers. On the basis of the field investigations, eight construction phases (CP1-8) and nine occupation layers (OL1-9) (Figure 3[b]) can be identified. The total occupation and raising of the site lasted approximately 1 century (860-960 A.D.). The purpose of this micromorphological study is threefold: 1. To characterize further the various features, such as types of earth and types of occupation layers described during the field study (Langohr, 1991). 2. To test the various hypotheses formulated during the macromorphological study. These concern mainly the origin of the earth used to construct the hill and the human activities related to the occupation layers. 3. To study further the various characteristics related to diagenetic pedogenetic processes.
Oriol Munne - One of the best experts on this subject based on the ideXlab platform.
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Wireless Sensor Network Technology for Monitoring Moisture Content of Wood
SSRN Electronic Journal, 2014Co-Authors: Ivan Arakistain, Jose Miguel Abascal, Oriol MunneAbstract:Leaks represent a very important hazard for the buildings and they can affect all sorts of building materials and specially wood due to its hygroscopic properties. Excessive moisture content can affect in a negative way building processes such as the installation of Wooden Floors or the use of wood as a structural material. Moisture meters can provide prompt and non-destructive determination of wood moisture, and as such are among the most useful tools available to wood products manufacturers and scientists. However, a continuous monitoring system is needed in order to avoid excessive moisture content which can damage Wooden Floors as well as structural wood. Data and procedures are presented in order to develop a suitable monitoring tool based on wireless sensor networks to provide an electronic tool of active security both for the installation of Wooden Floors and for the proper maintenance of existent buildings which have a timber structure.
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Wireless sensor network technology for moisture monitoring of wood.
arXiv: Other Computer Science, 2013Co-Authors: Ivan Arakistain, Jose Miguel Abascal, Oriol MunneAbstract:Leaks represent a very important hazard for the buildings and they can affect all sorts of building materials and specially wood due to its hygroscopic properties. Excessive moisture content can affect in a negative way building processes such as the installation of Wooden Floors or the use of wood as a structural material. Moisture meters can provide prompt and non-destructive determination of wood moisture, and as such are among the most useful tools available to wood products manufacturers and scientists. However, a continuous monitoring system is needed in order to avoid excessive moisture content which can damage Wooden Floors as well as structural wood. Data and procedures are presented in order to develop a suitable monitoring tool based on wireless sensor networks to provide an electronic tool of active security both for the installation of Wooden Floors and for the proper maintenance of existent buildings which have a timber structure.
