1,722,018 research outputs found
Concept, Design and Construction of an Aluminium Alloy Housing Prototype in Seismic Zone
No full textThe historical development of aluminium alloys in Structural Engineering was neglected until the 1970s due to the lack of technical regulations. Since then, there was a significant progress, particularly with the introduction of European recommendations and standards, such as Eurocode 9 and Eurocode 8, which cover the design of aluminium alloy structures and seismic-resistant buildings. The paper presents the construction of the first residential building in Europe with a seismic-resistant structure entirely made of aluminium alloy. It describes a prefabricated system designed specifically for this purpose, utilizing extrusion profiles for the gravity-resistant system and aluminium alloy shear walls for seismic resistance. The manuscript details the concept, structural design, and construction phases, showcasing the potential of aluminium alloys as a viable alternative to steel in building earthquake-resistant structures
Numerical Studies on Innovative Prestressed Aluminium Alloy Profiles for Curtain Wall Systems
No full textAluminium curtain walls consist of thin extruded aluminium profiles, which are bearded by building structure, glass fixed on profiles, and subsidiary materials, such as EPDM (Ethylene propylene diene monomer) gaskets, membranes, brackets, silicone, etc. They can be arranged according to either stick (assembled on site) or unitized (assembled in shop) systems. These curtain walls are light, resistant to corrosion, and provide a nice appearance to the building facades. The main disadvantage of aluminium alloy systems is linked to the high material deformability, which makes challenging to absorb the building sway induced by wind and seismic forces respecting the standard provisions. To overcome this structural limitation, in the paper, a novel profile made of aluminium alloy and reinforced with tensioned steel wires to be used for curtain walls was conceived in the framework of a research contract between the Department of Structures for Engineering and Architecture (DIST) and the CMS Srl company. Firstly, numerical analyses were performed using the ABAQUS non-linear code on several extruded profiles to evaluate the system sensitivity to the number and location of wires. Finally, the performance of the reinforced profile was compared to that of the unreinforced aluminium alloy member, allowing us to find the optimal configuration of the aluminium alloy-steel mixed system to attain the maximum increase of stiffness and strength
Design Method of Lightweight Steel Exoskeletons for Seismic-Energy Upgrading of Existing RC Buildings
No full textAll over the world, the built heritage suffered a lot of damages and collapses after seismic events due to several structural deficiencies. Also, it is known the importance of limiting energy consumption in the building sector, which is one of the major sources of greenhouse gas emissions. These issues suggested an integrated approach in the building retrofit. Among the multiple techniques developed in recent years, this research focused on lightweight steel exoskeletons combined with thermal insulating panels for seismic-energy retrofitting purpose. The main focus of the paper is to develop a seismic design method for lightweight steel exoskeletons to provide an efficient guide for designers. The used system is the Resisto 5.9 seismic coat, which is made of cold-formed profiles with bolted connections having X-bracing as seismic-resistant systems. The results of the research are herein presented with the application of the proposed procedure to an existing RC 2D frame building analyzed by a FEM calculation model. Starting from the capacity curves of the existing frame, the design method allows to size the cross-section of diagonal members. Subsequently, pushover analyses are carried out on the structure reinforced with the proposed system to assess the global behavior of the building and to validate the theoretical design curve. Finally, the results derived from the proposed analysis procedure show the effectiveness of the retrofitting system to obtain the seismic upgrading of the inspected RC structure, as well as the effectiveness of the presented design method
Conceptual Investigation of the Northridge’s Earthquake Structural Failures on Steel MRF by the Aid of Swiss Cheese Model
No full textOn January 17, 1994, the Northridge earthquake, USA, struck the southern California area, causing unexpected damage to beam-to-column welded steel moment-resting frames (WMRF). After 30 years of this benchmark earthquake, it is interesting to investigate this event from a different point of view, namely, through a combined consideration of forensic engineering and risk management. The Swiss Cheese Accident Model provides an excellent framework for understanding how a series of minor or major errors or failures can align to result in a catastrophic event. The study presents an effort to approach the failure of the Northridge earthquake of steel WMRF through the view of the Swiss Cheese accidental model. The investigation identified the layers of defense and their associated holes. Moreover, we discussed the weaknesses, corrective actions, and improvement actions
Numerical Model and Seismic Vulnerability of Infilled Industrial Steel Structures
No full textA numerical framework for the seismic vulnerability assessment of industrial steel structures with masonry infills is presented. This peculiar structural typology has been extensively observed in many industrial areas in the Italian territory and is commonly characterized by the absence of bracings or any anti-seismic design criteria. As such, masonry infills represent the main seismic resistant structural component which, then, cannot be neglected in the vulnerability analyses. An efficient finite element model is adopted to simulate the structural nonlinear behaviour, considering both geometrical and constitutive nonlinearities. Epistemic uncertainties related to the geometric data and the mechanical characteristics of steel and masonry are considered. The approach is tested for infilled steel structures in the industrial area of Spezzano Albanese, in southern Italy. Fragility curves are constructed considering or not considering the presence of infills and the results show that the seismic behaviour is drastically different in the two cases. In particular, it turns out that if the mechanical contribution of the infill is neglected, the structures exhibit high damage even for low intensities of the seismic action
A New Seismic Coating System for Requalification of Existing Constructions
No full textThe current trend in the retrofit of existing buildings is to think mainly to environmental aspects, giving few attention to seismic issues. Contrary, recent EU’s policies in this field are based on integrated approaches able to improve both energy and earthquake performances of the existing built-up. Therefore, the so-called seismic coats have been launched on the building market. In this framework, the design of a new envelope system, named DUO SYSTEM, for seismic-environmental requalification of existing constructions made of masonry or reinforced concrete is presented and illustrated in the present paper. The novel seismic-environmental coating system is composed of a cold-formed aluminium framed structure equipped with a shear wall system, represented by either OSB panels or aluminium alloy trapezoidal sheeting, which are designed according to the Sheeting Braced Design theory. In the current work, firstly, the novel seismic coat has been presented by detailing all its components. Secondly, the anti-seismic solutions based on OSB shear walls have been used for upgrading two existing school buildings, one made of masonry and the other made of reinforced concrete. Finally, the comparisons of performances of examined buildings before and after the intervention have been made to evaluate the benefits provided by the proposed coating system under seismic and environmental viewpoints
T-resolution: refinements and model elimination
Full text linkT-resolution is a binary rule, proposed by Policriti and Schwartz in 1995 for theorem proving in first-order theories (T-theorem proving) that can be seen - at least at the ground level - as a variant of Stickel's theory resolution. In this paper we consider refinements of this rule as well as the model elimination variant of it. After a general discussion concerning our viewpoint on theorem proving in first-order theories and a brief comparison with theory resolution, the power and generality of T-resolution are emphasized by introducing suitable linear and ordered refinements, uniformly and in strict analogy with the standard resolution approach. Then a model elimination variant of T-resolution is introduced and proved to be sound and complete; some experimental results are also reported. In the last part of the paper we present two applications of T-resolution: to constraint logic programming and to modal logic
Enhancing Seismic Performance of Steel Plate Shear Walls Through Innovative Design and Curved Shape Slots
No full textThis study introduces innovative Steel Plate Shear Walls (SPSWs) with a specific shape as seismic energy dissipative devices for both new and existing structures. These systems incorporate curved shape slots and varying opening ratios, significantly impacting their seismic performance. A comprehensive numerical investigation of the cyclic behavior of these panels is conducted using the Finite Element Method (FEM) with ABAQUS software. The numerical model is validated by means of the comparison with experimental data of previously tested specimens available in the literature. The analyses provide a thorough assessment of the hysteretic behavior of specimens, including key performance metrics, such as maximum load-carrying capacity, initial stiffness, and out-of-plane displacements up to 5% drift. Additionally, eigenvalue analysis is employed to calculate the critical elastic buckling load for each specimen. The study compares the ratio between the yielding force and the elastic buckling force, as well as critical parameters influencing out-of-plane deformations, for each configuration. Finally, the optimal configuration of innovative SPSWs with a specific shape, incorporating curved shape slots, is suggested based on design parameters related to the hysteretic behavior
A Comparison of Different Formulations for an Inverse Source Magnetostatic Problem
No full textThe resolution of inverse problems is a quite common task in the diagnostic processes based on electromagnetic field measurements, in particular when internal characteristics of the object under test are to be estimated from external measurements. This class of problems are well known to be ill posed, and a number of different techniques have been proposed to make the estimation process reliable. In this paper, with reference to an application in the framework of low frequency magnetic fields measurements, the effects of different choices for the degrees of freedom are discussed, with the aim of improving the solution reliability
SEISMIC VULNERABILITY ASSESSMENT OF A 17TH CENTURY NEAPOLITAN FARM
Full text linkIn this paper, seismic vulnerability appraisement, restoration, and consolidation plan of a 17th century masonry building (Rossi farm) with cultural and artistic value located in a small city near Naples are reported and discussed. This case study is presented and described, providing historical data and information about its actual conditions, spaces, functions and structures. Once the crack pattern detected in the building has been appropriately traced, the knowledge is deepened by performing all the three seismic risk assessment analyses proposed by the “Italian Guidelines for the assessment and reduction of seismic risk of cultural heritage". The first evaluation level is a qualitative and simplified tool allowing for the knowledge of the risk level of the building under study. Afterwards, the structure has been subjected to more accurate investigations dealing with its local mechanisms and global behaviour in the second and the third evaluation levels, respectively. In all three analysis phases, the results have shown the high vulnerability of the masonry farm. Based on these results, a consolidation plan, according to the Cultural Heritage Italian Guidelines suggestions, has been proposed
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