The paper focuses on tall timber buildings. The major aim of this paper is to identify the most sustainable and efficient structural system to increase the height of timber buildings, also ...considering steel–timber hybrid structures. First of all, a brief review of tall buildings’ evolution is presented to understand why tall timber buildings are considered nowadays and which are the most adopted structural solutions. Then, the case study of the tallest timber building in the world is selected and utilized as an archetype. Once the model has been validated, seven alternative structural systems are considered by varying the horizontal load resisting system and preserving the same member cross-sections as the reference building. The variants are tested and compared in terms of material consumption, vibration characteristics and lateral load response. Using the best structural system, the height of the building is increased, pushing the structures beyond the current limits and identifying the most efficient option. The idea is to preserve the column cross-sections and balance the increase in gravity loads due to the additional floors by replacing the concrete floors with timber counterparts. With the same structural system, equivalent steel–timber hybrid solutions are finally tested and compared in terms of sustainability to timber-only counterparts and to the original project. The results of analyses show that the use of steel elements combined with timber can lead to optimized and sustainable structural solutions.
The paper focuses on a review of augmented reality/mixed reality (AR/MR) technologies in the perspective of the application to structural health monitoring (SHM) for submerged floating tunnels (SFT). ...In particular, Microsoft HoloLens Devices (MHD) are precious tools for survey purposes, since they allow the superimposition of information about the surrounding environment, leading to its complete control with a reduction of errors. Preliminary, the most common SHM techniques in traditional waterway crossings are examined, for identifying those best fitting with SFTs. The infrared (IR) thermography for damage detection is deepen. The possibility of connecting IR Camera and MHD, with the aim at facilitating the acquisition of thermal data and enabling stereoscopic thermal overlays in the worker’s augmented view, is examined through three different experiments, namely steel fatigue crack detection on a steel plate, CFRP delamination detection and coating thickness detection on a steel members. To this purpose, a simulation of the combination of thermal image with HoloLens is performed showing the potentiality of how the view of the thermal camera in front of the user can enhance the perception of possible problems on the target structure earlier with respect to analyzing the data afterwards.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Arundo donax L. (ADL), also known as giant reed or Mediterranean cane, is a riparian herbaceous species characterized by long and robust stems. Classified as an invasive species because of its high ...capacity to grow, this natural material has been used for centuries in several sectors: handicrafts, agriculture and, mostly important, in buildings. Even if this species is easily found in the most of Mediterranean landscapes and is characterized by a large employment, most of its physical and mechanical properties are still unknown. In this context, the paper focuses on the identification of the ADL properties as plant and the assessment of the benefits to use Arundo donax in the field of constructions, especially in terms of environmental impact, through a careful analysis of existing architectures. Moreover, a simulation for the determination of the thermal performance and energy demand of a building that use Arundo donax as insulating material is proposed, also comparing the results to traditional insulating products.
Moment Resisting Frames (MRF) should ideally dissipate the seismic energy through the development of plastic hinges in the beams and at the column bases with the purpose to pursue a global failure ...mechanism. The current seismic design criteria, through hierarchy resistance and ductility requirements, are conceived to achieve this objective. However there are still some inaccuracies in the prediction of the structural performances, mainly under cyclic loadings, as much important as the number of bays and stories augments.
The current paper would give a contribution for deepening key issues related to MRF seismic behavior, presenting the numerical simulation of some literature experimental tests conducted on simple portal MRF subjected to monotonic and cyclic loads both in presence and in absence of vertical loads.
The refined Finite Element structural models of the study systems are developed through the software ABAQUS (v6.13-1). The models set up provide very good replications of both monotonic and hysteretic behaviors in terms of strength, stiffness, ductility and energy dissipation. They represent powerful analysis instruments to perform parametric studies, aiming at detecting the main factors affecting the seismic behavior of MRFs, thus leading towards appropriate design criteria.
Italy is located in a very active seismic zone, and many earthquakes have marked the country, some of them in the recent past. In order to take adequate measures of seismic prevention and protection, ...in the last decades, the Italian Civil Protection Department (DPC) initiated a survey and introduced a specific form for the quick and/or post-seismic assessment of buildings. This is useful to obtain statistics on the types of structures and their vulnerability and a judgement on the damage, leading to a decision about the possibility of reuse and/or the level of retrofitting to be applied. Those activities have been developed since the beginning of 2000. This task is currently carried out by the Italian DPC-ReLUIS project research, line WP2 on the inventory of building structures, setting up the CARTIS form for any structural type, like masonry, reinforced concrete, precast concrete, steel, and timber structures, the latter being mainly related to large span buildings, extensively used in Italy. In this context, the paper presents the first draft of the CARTIS form for large span timber structures that provides a general description for typical structural schemes, through the singular points commonly considered as seismic structural vulnerabilities. Moreover, the statistics on timber large span structures based on a sample of 10 buildings is presented.
The paper deals with an experimental study for in situ mechanical characterization of ancient timber members using combined Non Destructive Testing (NDT) techniques. An experimental campaign, ...including non-destructive and destructive tests, was developed on timber structural elements and defect-free specimens, made of old chestnut wood (
Castanea sativa
Mill.). The following NDT methods were employed in the research activity: hygrometric tests to estimate wood moisture content; ultrasonic investigations to determine stress wave properties; sclerometric tests to assess material hardness and superficial consistence; resistographic measurements to detect internal defects and density variations. Destructive tests in compression parallel to grain and in bending were performed to assess stiffness and strength properties, post-elastic behaviour and collapse mechanisms of the timber elements. Experimental results are discussed and statistically analyzed. Correlations between non-destructive and destructive parameters are provided, based on linear regression models, for the prediction of the wood density, strength and modulus of elasticity of the tested old chestnut timber. The analysis shows that the use of NDT techniques is a useful supplement to the traditional visual grading, allowing a reliable mechanical identification of timber members in practical applications, leading to the appraisal of the timber structures safety and integrity.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
•A procedure for in situ determination of density of timber members is presented.•The method is based on ND tests carried out in transverse direction.•The ND test considered are sclerometric needle ...penetration and resistance drilling.•The method is defined based on the statistical elaboration of measured data.•The method is specifically conceived for built cultural heritage of notable value.
In the context of a wide research study for in situ mechanical identification of ancient timber structures by non-destructive techniques (NDTs), the paper illustrates a method for the determination of the density of timber elements, through the statistical combination of in situ sclerometric needle penetration and resistance drilling parameters measured in transverse direction. The method is applied to ancient chestnut samples, even though it can have a general validity. Once estimated the density, the mechanical properties both in compression and in bending can be evaluated through correlations with density.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The recent development of timber structures, thanks to new materials more and more efficient from the mechanical point of view, allows the application, as seismic resistant systems, of both framed ...and braced multistory multispan timber structures, which are already well consolidated in the field of steel constructions, they offering excellent seismic performances. Although materials are different, the structural systems have the similarity to be assemblage of structural members connected each other. Therefore it is possible to apply the same seismic design approach, by transferring the knowhow from steel to timber structures and adapting the design rules to the peculiarities of timber. In particular the seismic design parameters are to be calibrated and the dissipative zones to be characterized, they being the connections themselves or specific dissipative devices.
In this context, the paper deals with the application of steel links for the development of seismic resistant dissipative heavy timber frames: steel links have the aim of dissipating seismic energy, while timber elements and steel connections remain in the elastic field, according to capacity design. Specifically, 2D single-storey timber structures equipped with dissipative links, in different structural configurations, are studied. They have been designed through linear dynamic analyses. Therefore, non-linear static analyses are performed, using the structural calculation program SAP2000, with the aim of evaluating the global behaviour and determining the behaviour factors for each structural type. The study proves the suitability and the efficiency of the proposed system and design procedure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Timber structures mechanical identification in monumental buildings is dealt with.•The timber roof of the Diplomatic Hall of the Royal Palace of Naples is studied.•In situ investigations, as prior ...to structural analyses, are addressed.•Both geometrical and visual surveys are presented, in addition to in situ ND tests.•Geometry, static schemes, wooden species, defects and degradations are determined.
Especially in monumental buildings the preservation is compulsory for perpetuating the history of the construction technologies and of the past used materials. Therefore, the evaluation of the residual bearing capacity of existing structures is necessary, in order to detect any structural deficiency and to select proper restoration interventions. First of all a comprehensive knowledge of the structures should be acquired through in depth surveys, aiming at the structural identification.
In this context, the paper exemplifies the structural identification procedure with reference to the complex covering timber structure of the Diplomatic Hall of the Royal Palace of Naples. The focus is specially on the in situ investigation phase, as the first essential step prior to the structural analysis of stress and deformation. Both geometrical and visual surveys are presented, in addition to in situ ND tests, the latter being performed by the CNR IVALSA Institute according to the current Italian Rules. As a result, the geometrical and static schemes were identified, the wooden species distinguished, the moisture content assessed, defects and degradations due to both aging and biological attacks detected, the effective transversal section determined and the effectiveness of the connections evaluated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The paper deals with the experimental analysis of an innovative connection system for composite timber-steel-concrete floors. The connection device consists of a collar composed by two or more parts, ...astride the timber beam, bolted together at adjacent wings. A rubber layer is interposed at the collar-beam interface. The slipping action transmission is guaranteed by the superior wings of the collar or by a steel stud, purposely welded to the collar in the upper part, which are immersed in the concrete cast. In this paper push-out monotonic tests on several rectangular-shaped configurations of the connection system are presented, being part of a more comprehensive experimental campaign, aimed at the system performance evaluation and optimization. First, the preliminary numerical analyses, meant to define both the best geometrical characteristics of the specimens and the configuration of the testing apparatus, are illustrated. Then the push-out tests, considering subsequent improvements of the connection system are detailed. The connection behaviour is discussed in terms of force-slip relationship.
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