Search results for "Steel structures"
showing 9 items of 9 documents
Sul controllo del meccanismo di collasso di controventi eccentrici
2007
The effectiveness of different non-linear static procedures, for the detection of the collapse mechanism of eccentric braced frames, is investigated. EBFs introduced into truss frame structures are considered. For such a typology of structures, plastic deformations are concen-trated in a single resistant element at each floor, greatly increasing the risk of the formation of soft storey mechanisms, even if the structure is designed according to the capacity design. The results of different non-linear static procedures are compared to those obtained by incremental dynamic non-linear analysis, considering a meaningful set of artificially generated stationary accelerograms, compatible with a ta…
Tandem laser-gas metal arc welding joining of 20 mm thick super duplex stainless steel: An experimental and numerical study
2020
The present work covers the topic of strains and stresses prediction in case of welded steel structures. Steel sheets of 20 mm thickness made in UR™2507Cu are welded using a laser and gas metal arc welding processes combination. The focused laser beam leads the arc in a Y-shape chamfer geometry. Both sources are 20 mm apart from each other in order to avoid any synergic effect with each other. In order to predict residual strain, a 3D unsteady numerical simulation has been developed in COMSOL finite element software. A volume heat source has been identified based on the temperature measurements made by 10 K-type thermocouples, implanted inside the workpiece. The 50 mm deep holes are drille…
Risk based Fatigue Inspection Planning – State of the Art
2013
AbstractThe present paper presents the methodology and the practical calculations for risk based inspection planning of fatigue cracks in welded offshore steel structures. Due to the uncertainty in the variables involved in the problem the planning has to be carried out by stochastic modeling and risk based assessments. Scatter in potential crack growth has to be analyzed by applied probabilistic facture mechanics and the uncertainty in the performance of the actual inspection technique has to be determined. With given risk acceptance criteria the practical outcome of the analyses is recommended inspection techniques and associated planned inspection time intervals. The classical theory is …
Seismic assessment and retrofit of a concrete building highly damaged by reinforcement corrosion
2020
In existing concrete structures damaged by corrosion, the limited quantity and poor distribution of reinforcements as well as a lack of seismic details are common to many cases because they are built before the advent of seismic codes. In this paper the seismic assessment and retrofit of a concrete building sited in Sicily is presented in order to show a case-study of a corroded reinforced concrete structure to be trans-formed with new structural elements for functional reasons linked to Civil Protection. After many decades of complete abandonment, the structure was strengthened with different strategies, allied to the construction of new steel-concrete composite floors: concrete and steel …
Numerical validation of LRPH behaviour by FEM analysis
2019
LRPH connection is a special steel device mainly usable to join beam elements of plane or spatial steel frames. It is identified as Limited Resistance Rigid Perfectly Plastic Hinge and it is covered by patent n. 102017000088597 at the Italian Ministry of Economic Development and identified in the International Patent System with the number PCT/IB2018/055766. The fundamental innovations of this device are the mutual independence of their own resistance and stiffness features and the respect of assigned constraints related to the elastic and limit behavior of the joined elements. Within the frame structural scheme, the device plays the role of a rigid perfectly plastic hinge, and it is consti…
Comportamento di una passerella pedonale strallata nei confronti delle azioni del vento
2007
The wind behaviour of a stayed footbridge has been analyzed. In order to avoid aeroelastic phenomena, an experimental campaign on a 1:15 scale model has been realized at the boundary-layer wind-tunnel of the Milan Polytechnic. The aerodynamic characterization of the structure has allowed to direct the project towards the choice of non-solid barriers, but with a medium porosity, by avoiding possible problems that can lead to ultimate limit state condi-tions of the structure (e.g., flutter or vortex shedding). In this way the quantitative effect of barriers has been estimated deducing reliable values not only for the alongwind forces, but also for the crosswind and torsional actions.
Limited Resistance Rigid Perfectly Plastic Hinges for Steel Frames
2017
The paper concerns the proposal of a new special device for steel frames that can be utilized as external constraint as well as internal one connecting the structure beam elements. The device is designed as a rigid perfectly plastic hinge characterized by suitably chosen stiffness and resistance. Its constituting material is steel. The elastic stiffness and the limit resistance, treated as independent of each other, are fixed with the aim of satisfying special features required to the structure. The proposed device is thought as a sandwich section with wing thickness appropriately variable. Its dimensions are designed so that it can exhibit the fixed independent stiffness and limit resistan…
Interventi migliorativi in acciaio a tutela delle opere di interesse storico-monumentale dal rischio sismico
2007
The research concerns the analysis of structural behaviour of some historic-monumental buildings in which steel structures are used for the seismic protection. A dynamic model has been made to individuate the macro-element with an high seismic risk, that is, for church studied, the drum-dome system. Then a scaled model has been tested to determinate the evolution of the lesions, the retrofitting works, that are constituted by steel frames, bare or braced, inserted inside door/window holes of the drum-dome system, and the variation structural ductility. An elastic linear analysis, with a FEM software, has been developed for other type of buildings, in which the vertical structures are made w…
Progetto di Strutture in acciaio per le nuove costruzioni e per gli interventi di consolidamento. IV Edizione
2005
The book is a state of the art summary of recent development in the behavior, analysis and design of steel and composite structures. The book provides advanced students, researchers al professionals in civil and structural engineering with the basic principles upon which the modern codes are based. In the first part, the materials, the actions and the sectional behavior are analyzed on the base of the limit state theory. Then the connections (bolted and welded)and the stability effects are examined. In this way is possible speak about seismic performance, retrofitting an refurbishment of existing buildings, referring to the italian rules, to the european codes EC3, EC4 and to the AISC rules.