1,721,439 research outputs found
On failure modes and design of multi-bolted FRP plate in structural joints
No full textTechnical recommendations for design of all FRP structures are by now available and recognized. Inside this frame, the design of all FRP bolted connections with steel bolts has a not negligible position due to its importance in application, especially when bolted connection have, or could have, a significant role in term of bearing capacity and hierarchy between structural parts. The design strength formula for bolted FRP connections proposed in European and national normative and guidelines - define different approaches in function of the numbering of bolts, the geometrical characteristics and typology of each joint and action, that could be out or in plane. Nevertheless, the specific case of multi-bolted (MB) or high-multi-bolted (HMB) FRP plate used in structural joints has been not yet clearly faced, nor from experimental and numerical approach, nor for failure mode. Besides also the strength design approach becomes complex in presence of MB connections. By the way, this research try to investigate specifically this point starting from recent experimental based results dedicated to the structural performance of MB and HMB FRP plates used in connections, and in comparing them with expected ultimate strengths and available design formula. In comparing available formula with experimental outputs - and in verifying their reliability/compatibility - the proposed investigation shows also some thought onto the potential oversize/undersize of this kind of structural joints. The research is exclusively dedicated to the MB FRP plates produced by pultrusion process and used in joints subjected to only in plane action
Damage assessment of GFRP pultruded structural elements
No full textThis study shows a procedure for the identification of the mechanical characteristics and dynamic parameters of glass fiber-reinforced polymer (FRP) pultruded elements. The matching between analytical model and experimentally acquired modal and natural frequency data is used to investigate the homogeneity of materials (resin and fibers) and the mechanical characteristics variation for pultruded profile with different cross sections, also in presence of induced damage. The experimental results are given primacy, and then the model must be modified by trial and error methodologies of model updating approach. This work depicts the sensitivity analysis based FE model updating procedure and its application to mechanical characteristics and damage assessment of different GFRP members from modal parameters. The accuracy analysis, that relies upon the relative confidence between the results (exp. and analytical) features a FE model of pultruded composite profiles with orthotropic behavior. The same structures were subjected to damage and their identification is based on dynamic response through the curvature mode shapes. This approach allows to know the location and size of damage, the change in dynamic characteristics and thus the decrease in strength and stiffness. The damage identification was carried out also with FE analysis by updating the undamaged beam model. © 2012 Elsevier Ltd
Using Experimental Dynamic Modal Analysis in Assessing Structural Integrity in Historic Buildings
No full textThe research optimizes the use of the dynamic modal analysis based on experimental data as a non-destructive approach in identifying the structural integrity of historic buildings. Currently dynamic modal analysis is widely used to global understand displacements of construction given their size and structure. This research proposes to simplify the ways in which to assess the structural conservation management required for historic buildings including complex monuments. The simplified approach suggested in this research is based on using ambient vibration as the excitation and the use of accelerometer sensor applied in appropriate configuration. The proposed approach, would provide a more expeditious methodology in assessing structural integrity than other methods. The research validates the results achieved with the Experimental Dynamic Modal Analysis (EDMA) methodology by comparing experimental results with those achieved with comparable FE assessment
Sul comportamento strutturale di elementi in c.a.p. a parete sottile e provvisti di rete elettrosaldata ad elevata duttilita
No full text
Sulla risposta sismica di strutture in PFRP: il caso della copertura della Chiesa di S. M. Paganica all’Aquila – Parte I: il materiale
No full textOn the monitoring of historic Anime Sante church damaged by earthquake in L’Aquila
No full textThe paper shows the activity of a 2-year static and dynamic monitoring activity to check the structural response and the actual level of damage of a historic church hit by earthquake in L'Aquila (Italy) in 2009. Structural health monitoring was carried out with accelerometers and transducers that recorded time histories of the main earthquake-induced ground motions and ambient vibrations. The paper focuses particularly on residual performance and assessment of the ancient church after six earthquake response data setbecause of the seismic swarmvia a modal identification of output-only systems by using frequency domain decomposition. In this way, fundamental frequency, mode shapes, damping ratios and displacements can be estimated without knowing the input that has excited the system. The dynamic monitoring provides also a way to check possible drops of tension in the cables and relaxation in the FRP belts used for safety. Efficiency and reliability of modal identification of basilica-type churches, via the dynamic response of macro-elements only in comparison with the whole analysis, are finally proposed. Copyright (c) 2012 John Wiley & Sons, Ltd
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