1,721,129 research outputs found
A shear deformable steel-concrete composite beam model
No full textThis paper presents a model for the analysis of composite beams taking into account the
overall shear deformability, warping of the slab cross section and of the steel beam and partial
shear interaction between the slab and the girder. A suitable restrained displacement field is
introduced by considering the longitudinal displacements given by the product of known
shapes modulated by unknown functions variable along the beam axis. The warping functions
are obtained by considering the problem of unrestrained thin-walled members subjected to
self-equilibrated elementary load schemes. The governing equations are derived, according to
the stiffness method, both in the weak and strong forms starting from the Virtual Work
Theorem which makes it possible to consistently obtain the resultants of the stresses, the
applied forces and the inertia involved in the problem. Some simple applications show the
capacity of the model to describe displacements and stresses
Lateral impact loading and snap-back testing to estimate linear and nonlinear dynamic response of near-shore piles
No full textLinear and Nonlinear Dynamic Response of Piles in Soft Marine Clay
No full textThis paper presents the results of free vibration tests carried out at different load levels on a system of three near-shore steel pipe
piles vibro-driven into soft marine clay. Piles are arranged in an L-shaped horizontal layout and are free at the head. The instrumentation
consists of strain gauges placed at selected levels along the shaft of the loaded pile and accelerometers at the head of the receiver piles. The
aim of this experiment is to analyze the dynamic soil–water–pile and pile-to-pile interaction and to investigate the development of nonlinearities
at increasing load levels. The results of experimental modal analyses, in terms of natural frequencies and damping ratios of
the system, are presented and the complex dynamic behavior of the vibrating soil–water–pile system and the pile-to-pile interaction are
discussed. For a better reliability assessment of the system response in the range of linear behavior, the results of free vibration tests at
the lowest level of the applied loads are compared with those obtained from impact load tests
A novel optimal sensor placement software for supporting the development of monitoring systems in civil engineering structures
Full text linkThis paper proposes a new software for the Optimal Sensor Placement (OSP) featuring an intuitive graphical user interface that simplifies its use. The software automates OSP analyses, enhancing efficiency, reducing human error, and supporting the development of effective dynamic monitoring systems as a result. It incorporates five well-established OSP methods that allow users to explore the optimal number of sensors and their locations on a structure. Moreover, it accommodates both numerical and experimental data as input. Results are provided in both tabular and graphical format. It can be used in all types of structures, even though it was developed primarily for civil engineering applications. A key innovation of the proposed software is its ability to perform OSP analyses on multi-block, complex, and non-orthogonal buildings, increasing versatility. After a comprehensive description of the new software, its applicability and potentiality are shown through simple applications, as well as with real case studies
Long term behaviour of composite continuous two-beam decks with HPC slab
No full textBy using a beam model that accounts for interface shear connection deformability and slab loss of planarity (shear-lag), the long term behaviour of composite continuous two-beam decks with high performance concrete slab is analysed. The main actions usually considered in composite bridge decks design, namely static and geometrical actions and slab shrinkage, are separately analysed by determining, for each, the effective slab width, that describes the shear-lag effect on the cross section and its time evolution
Nomograms for the pre-dimensioning of RC beam-column joints according to Eurocode 8
No full textBeam-column joints in reinforced concrete frame buildings are very important elements whose design must be done with particular attention to guarantee the development of full strength and ductility of structural elements, as well as the respect of the hierarchy principles. Nowadays many codes worldwide require the evaluation of the beam-column joint capacity and provide expressions for the verification of this fundamental element. The respect of these verifications may lead the designer to take decisions which can affect, even significantly, the structural component geometry and also the architectural design of buildings. In this paper a simple and fast-to-use graphical tool is provided to support the design of beam-column joints satisfying Eurocode 8 verification expressions. In detail, nomograms are proposed with the great advantage of being largely applicable for all types of beam-column joints. The use of nomograms makes it possible to obtain an estimation of the beam-column joint sizing and of the horizontal hoop amount. If the joint dimension reveals to be underestimated and/or the hoop amount leads to an excessive close spacing, the designer can promptly modify the design at the early stages of the design process. Worked examples are also proposed, and many types of nomograms are reported in a dedicated appendix
Modelling Strategies for the Updating of Infilled RC Building FEMs Considering the Construction Phases
No full textThis paper deals with modelling strategies for the updating of Finite Element Models (FEMs) of infilled Reinforced Concrete (RC) frame buildings. As is known, this building typology is the most adopted worldwide for residential houses and strategic buildings, such as hospitals, schools, police stations, etc. The importance of achieving trustworthy numerical models for these kinds of structures, especially the latter ones, is clear. The updating procedure mainly consists in changing the geometrical and mechanical material properties of models until pre-determined convergence criteria are verified, the latter based on the comparison between numerical and experimental outcomes. In this work, the modelling strategies that can be adopted to refine FEMs of infilled RC buildings are treated in-depth, starting from the simple model usually developed for design purposes. Modelling techniques relevant to the geometry, the mechanical properties, the mass, and the restraint conditions of the model are discussed. Moreover, the approaches that can be adopted to calibrate numerical models during the construction process are addressed as well. Then, an application of the proposed strategies is provided with reference to a real building that was investigated during its construction. The proposed modelling strategies proved to be effective in the model updating of the considered building and provide useful support for the calibration of FEMs of this building typology in general
Load-consistent effective widths for composite steel-concrete decks
No full textSteel-concrete composite continuous decks are widely used in viaducts and bridges with medium span length (40-100 m). Such decks are usually composed of two steel beams or a single box girder, even in the case of wide concrete slabs (>20 m), that can be sustained by cantilevered cross-beams or be transversally prestressed. In this kind of structure the usual assumption of bending theory, according to which the plane cross-sections remain plane after loading, is not realistic because the slab undergoes a significant warping which is responsible of a non-uniform stress distribution on the slab cross section (shear-lag effect).
In the design of such decks, the main codes of practice (e.g. Eurocode 4) suggest to take into account the shear lag effect by reducing the slab width (effective width method) according to simple formulas, depending on the bridge geometry, obtained and validated for external static actions. However, their use for other kinds of actions, such as geometrical actions (support settlements), concrete shrinkage and thermal actions, is not supported either by numerical analyses nor by experimental tests.
The paper presents new formulations for evaluating the slab effective widths of steel concrete composite bridge decks depending on the kind of loading. Such formulations have been validated by means of a wide parametrical analysis performed thanks to a numerical procedure proposed by the authors. The method proposed can catch the effects of a single load layout, as well as the maximum effects obtained by considering the envelopes of bending moments as usual in bridge design
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