1,720,969 research outputs found
Structural behaviour of contemporary vaulted spaces with complex ashlars: the Abeille’s sail vault
Full text linkThe aim of the research is to investigate the static and dynamic behaviour of contemporary vaulted spaces, generated by the Flat Vault of Abeille patented in 1699. In fact, its reinterpre-tation and its use in architecture can both enhance the existing architectural heritage and char-acterize the new construction of building through the use of traditional construction materials and techniques. It follows that the identification of this “new type” of vault is essential to de-sign it correctly and to optimize the geometry for structural purposes.
The Abeille-Type ashlar is a polyhedron that has two axial sections, in the shape of an isosceles trapezoid, oriented in opposite directions. The arrangement of the ashlar takes place in the two orthogonal directions creating a bidirectional flat plate, with a single type of optimized ashlar, whose geometry guarantees the mutual support of the individual blocks of the vaulted system, once assembly is complete. Starting from this ashlar and applying its deformation on curved surfaces, it is therefore possible to design “contemporary” types of vaults, characterized by complex ashlars in order to optimized both an aesthetic-formal and a structural function.
The research proposes to apply already consolidated structural analysis methodologies – on traditional vaults – on this structure and describes the results of an experimental with quasi-static tests on a 1:8 small-scale vault model made of 3D printed blocks assembled with dry joints. In particular, shear in-plane and tilting tests were carried out by means of manual ac-tuators and controlled with incremental displacements. Different configurations are investi-gated both for the shear failure (simple or pure shear) and the tilting collapse (different in-plane angle). The results experimentally obtained were analysed in terms of damage/collapse mechanisms, strengths capacity and ultimate displacements.
The Distinct Element Method (DEM) will be used for the numerical analyzes, being until now the most accurate and realistic for masonry structures, since it can take into consideration their discontinuous nature and the interlocking/toothing of the individual elements. In fact, it allows to investigate the vault ashlars as rigid and separate entities, witch interact with each other through the block planar interfaces; so the stability and the deformation of the whole vault is managed by the join contacts.
Both experimental and numerical results furnish important data to formulate the behaviour of this vault. After the validation the results are extended to a full-scale vault by means of the similarity criteria, whose efficacy in the generalization of the results from the model to the prototype is demonstrated. In this way, the model can be finally adopted to simulate the be-haviour of a contemporary vault with the Abeille-Type ashlars
Assessing the Influence of RMS and VDV on Analysis of Human Perception of Vibrations in Buildings Caused by Selected Sources of Traffic
Full text linkThis research paper delves into the nuanced effects of traffic-induced vibrations on human comfort and perception within residential and commercial buildings. By prioritizing the influence of vehicle types—including metro trains, trams, and cars—over their speed or mass, the study presents a novel perspective on addressing vibrational comfort. Conducted in the urban context of Warsaw’s metro line construction, this investigation employs a rigorous methodology, utilizing both the Root Mean Square (RMS) and Vibration Dose Value (VDV) analytical methods to quantify vibrational impacts. The findings illuminate the distinct contributions of various transportation modes to the perceived vibrations, offering significant insights into the complex relationship between the Human Perception of Vibration Index (HPVI) and VDV values. It underscores the necessity of integrating a multifaceted consideration of vehicle type, operational dynamics, and urban infrastructure in the strategic planning and design of buildings. Such a holistic approach is essential for mitigating the adverse effects of transportation-induced vibrations, thereby enhancing the quality of life and well-being of urban inhabitants
Rammed Earth with Straw Fibers and Earth Mortar: Mix Design and Mechanical Characteristics Determination
Full text linkRaw earth is one of the oldest building materials, which is suitable for various uses: from the construction of load-bearing walls to use for plasters and finishes. The presence of straw fibers can give different behavior to this material. The present paper illustrates preliminary sensory and qualitative analyses, and subsequent laboratory tests that allow the characterization of the raw earth material with straw fibers for rammed earth constructions through mechanized compaction and the identification of a compatible earth mortar. The raw material considered in this study is mainly clayey; for this reason, a mix design usable with the pisé (or clay) technique has been developed. Cylindrical samples have been made through a press and subject to unconfined compression and indirect tensile tests. The results of the tests showed consistent tensile and compressive strength values in the context of earth materials. At the same time, a study for the realization of a mortar with the same base soil was carried out considering four mixtures, in order to investigate the best compromise between workability, shrinkage and compressive strengths. The purpose of the study was to investigate the mechanical characteristics of the local material through preliminary and laboratory tests, to classify it according to the Unified Soil Classification System (USCS) and to verify its suitability for a possible use in the construction field
Correction to: Essential dynamic characterization of a historical bridge: integrated experimental and numerical investigations
No full textREINTERPRETATION OF THE HISTORICAL “ABEILLE” MASONRY VAULT
No full textIn European countries, the masonry vaults represent one of the most recurrent types of horizontal structural elements in architecture. For this reason, the evaluation of their mechanical behaviour is a recurring topic in the scientific literature. Within this category of dry vaults, the “Flat Vault” is less investigated but increasingly of interest for the world of architecture, due to the availability of digital design and fabrication tools. This paper investigates the study case of “Abeille Flat Vault”, in particular, the structural behaviour of this vault and its reinterpretation in space, for new buildings. This vault consists of single ashlars that compose a bidirectional plate in space. The geometry of the individual ashlar generates the interlocking mutual support and guarantees the stability of the whole system.
The aim of the work is to identify an approach for the design of the reinterpretation of “Abeille Flat Vault” deformed on a spatially curved surface so to obtain the structural behaviour of the in-plane horizontal shear distortion of the full-scale Abeille’s Sail Vault. So, the evaluation and the investigation of the structural behaviour turn out to be very important to obtain a coherent reinterpretation of this discontinuous vaulted structure, in order to enhance the existing Architectural Heritage and to characterize the realization of new buildings according to the guidelines of architectural restoration
Mechanical Characteristics and Water Absorption Properties of Blast-Furnace Slag Concretes with Fly Ashes or Microsilica Additions
Full text linkThe paper shows the results of an experimental tests campaign carried out on concretes with recycled aggregates added in substitution of sand. Sand, in fact, has been totally replaced once by blast-furnace slag and fly ashes, once by blast-furnace slag and microsilica. The aim is both to utilize industrial by-products and to reduce the use of artificial aggregates, which impose the opening of pits with high environmental damage. The results show that in the concretes so made the water absorption capacity has reduced and durability has improved. The test campaign and the results described in the present article are certainly useful and can be especially utilized for research on a larger scale in this field
Dynamic Identification on an Irregular Structure
Full text linkThis paper presents the experimental analysis on the “Municipal Headquarters” of Palagianello Town. This is a strategic building with a high complexity at planimetric and altimetric level, so it is interesting the evaluation of its structural dynamic performance in case of seismic emergency management. To this aim, environmental vibrations have been acquired in situ and accelerometers have been positioned in well-defined points. The data were analyzed with an easy and accurate process that includes the Operational Modal Analysis (OMA), to identify the natural frequencies, the mode shapes and the damping ratios with non-destructive testings. Subsequently, the experimental results were compared with those of two numerical models (with and without infill walls) defined by means of the finite element method (FEM); this allowed for better calibration of the model and to arrive at more realistic conclusions about the behavior of the structure. The paper discusses the influence of the stiffness contribution of masonry infills on the dynamic properties of the building. Moreover, it shows that the adoption of ad hoc chosen locations of the sensors could influence the accuracy of the experimental results, especially for structures characterized by irregularities
Flexible Polyurethane Adhesives: Predictive Numerical Model Calibration through Experimental Testing at Elevated Temperature
Full text linkThe thermo-mechanical behavior of polyurethane adhesive joints in wood structures is a crucial aspect that needs to be understood to ensure the durability and safety of timber structures, especially in seismic regions. As mass timber, particularly cross-laminated timber, continues to gain popularity as a building material, it is important to pay special attention to the behavior of connections between the timber elements. The use of flexible polyurethane adhesives presents a promising alternative to conventional mechanical connections in seismic-resistant timber structures. This research highlights the potential of polyurethane-based joints at elevated service temperature, offers a promising alternative to traditional wood joints, and suggests viability for post-fire restoration of wood structures. The response at the interface between wood and polyurethane under flexural stresses is also evaluated, underscoring the broader application possibilities of flexible adhesives in wood construction for mechanical and physical improvements
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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