Browsing by Publisher "Croatian Association of Civil Engineers"

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    Experimental and numerical investigation of RC beams strengthened with CFRP composites; [Eksperimentalno i numeričko ispitivanje armiranobetonskih greda pojačanih CFRP kompozitom]
    (Croatian Association of Civil Engineers, 2021) Demir A.; İnce Y.; Altıok T.Y.
    This study aims to strengthen reinforced concrete (RC) beams having insufficient shear capacity using Carbon Fibre Reinforced Polymer (CFRP) members and innovative anchorages. An innovative method is also proposed for strengthening beams in interaction site of adjacent structures. Test results show that the behaviour of beams has been improved with CFRP elements. The nonlinear finite element (FE) method, as well as American and Italian guidelines, are used to estimate theoretical capacity of the beams. Test results are compared with theoretical results. It can be concluded that proposed methods can be used reliably, and that the design of RC beams strengthened with these methods can be performed by design engineers based on simple calculations. © 2021 Union of Croatian Civil Engineers and Technicians. All rights reserved.
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    Numerical modelling of floating structure with coupled Eulerian-Lagrangian technique
    (Croatian Association of Civil Engineers, 2022) Gucuyen E.; Erdem R.T.
    Floating structures are complex systems composed of superstructure, floating-mooring components, and anchors. In this study, the behaviours of a pontoon, which is used as a floating structure, and four mooring elements under different wave loading conditions were investigated. A numerical analysis of the coupled motions of the pontoon, mooring lines, and marine environment was performed. While the mooring lines were modelled as wire elements, the pontoon was modelled as a rigid body with six degrees of freedom. Wave loading conditions were represented using two different wave spectra. The first spectrum (Case I) was generated based on a single sinusoidal wave utilising the JONSWAP spectrum, whereas the second one (Case II) was generated based a superimposed multi-sinusoidal wave. Time-varying motions of the pontoon and tensions of the mooring lines were determined based on the numerical analyses for Cases I and II. Critical values were determined using the results of both cases. The numerical solutions were based on bidirectional fluid-structure interaction (FSI) analysis. A fully non-linear free surface simulation was performed using the coupled Eulerian-Lagrangian (CEL) technique. Furthermore, numerical results were compared with the results obtained from analytical solutions of free surface elevations. © 2022 Union of Croatian Civil Engineers and Technicians. All rights reserved.
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    Performance assessment and strengthening proposal of an existing building; [Ocjena ponašanja i prijedlog pojačanja postojeće građevine]
    (Croatian Association of Civil Engineers, 2022) Erdem R.T.; Karal K.
    Due to major-scale earthquakes, revisions of earthquake resistant structural design methods have periodically been made in seismic codes. It is known that many existing buildings are located in active seismic zones in all parts of the world. Severe damage to structural members, with partial or total collapse of buildings, has been observed in past earthquakes. Consequently, the evaluation of seismic performance and strengthening techniques of the existing buildings according to various seismic codes has become a global issue in structural engineering. With the development of computer technology, non-linear methods have been offering increasingly reliable evaluation procedures in the performance-based assessment of buildings. In this study, non-linear performance analysis of an existing typical mid-rise reinforced concrete building is first performed according to Turkish Building Earthquake Code-2018 and American Standard, ASCE. After evaluation of damage to structural members, the building is strengthened by steel braces and the analysis is performed once again. The SAP2000 finite elements analysis software is utilized in the solutions. Damage ratios of structural members as well as modal properties and storey drift ratios are determined and compared according to both codes, and it is concluded that the proposed strengthening method could be a significant alternative in such buildings. © 2022 Union of Croatian Civil Engineers and Technicians. All rights reserved.
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    Analyses of damaged effects on jacket type offshore platform; [Analize učinaka oštećenja na rešetkasto postolje izvanobalne platforme]
    (Croatian Association of Civil Engineers, 2023) Gücüyen E.; Coşkun S.; Tuğrul Erdem R.
    In this paper, an offshore platform subjected to dynamic loading for different damage cases was modelled via fluid-structure interaction (FSI) analysis. Different damage models were considered in the case where one leg was broken, and the Young’s modulus of the damaged member was reduced with four different severity ratios. In addition to the five damaged structures, the undamaged structure was modelled according to two different leg spacing conditions. Thus, the damaged models were compared among themselves as well as with undamaged models. In this study, models were investigated using a numerical FSI technique. The numerical technique was verified using semi-analytical modelling. At this stage, the equation of motion of one of the structural models was solved using a semi-analytical method based on a multi-degree-of-freedom system. In addition, the numerical environment model was verified using a semi-analytical solution of the free-surface motion equation and the wave velocity-wave force curve. An Abaqus finite-element analysis program was used to model the structures and their surroundings. While the structures were modelled using the Lagrangian technique, the fluid surroundings were modelled using the Eulerian technique. Both the conditions of leg spacing and different severity ratios were modelled, and the most negative damage type was revealed. © 2023, Croatian Association of Civil Engineers. All rights reserved.
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    Investigation of concrete slabs made with cement based mortars under impact loads; [Ponašanje betonskih ploča od cementnog morta pri udarnom opterećenju]
    (Croatian Association of Civil Engineers, 2023) Tuğrul Erdem R.; Berberoğlu M.; Gücüyen E.
    As structural members can be subjected to impact loading during their service life, impact experiments are applied for various materials and objects by taking different methods into consideration. The effect of impact load on concrete slabs prepared with cement-based mortars is investigated in this study. A total of nine slab specimens measuring 500 x 500 x 50 mm are tested within the experimental program. Test specimens are prepared to provide different strength values and tested under impact load using the drop test setup. The impact resistance values of the specimens are determined based on the acceleration, impact load and displacement values, as obtained by measurement devices. In addition, crack distribution of the specimens is observed during impact tests. It has been noted that mortar types have a significant effect on the impact behaviour of the specimens. The finite element analysis is generated for each specimen to verify experimental results. Time histories of the acceleration, displacement and impact load values of the selected test specimens are compared. The relationship between experimental and numerical analysis results is presented, which reveals that the finite element procedure can be used in the evaluation of dynamic response of test specimens under the low velocity impact loading. © 2023 Authors. All rights reserved.