Assessment of RC Frames for SD Limit State Using Nonlinear Methods of Analysis According to EN 1998-3

Design of structures in seismically active areas according to EN 1998-1 includes a choice between two ductility classes, medium or high, without conditioning by other parameters or favouring any of them. The behaviour factor q is applied as a global reduction factor of internal forces that would develop in the structure in the event of elastic response. According to EN 1998-3 a seismic assessment is determined by comparing the demands with the corresponding capacities. For ductile element, seismic demand and capacity are expressed in terms of chord rotation. The research in this paper was focused on the study of influence of the design ductility classes, as well as of the design seismic actions and the number of frames storeys, on seismic response of reinforced concrete frames designed according to European codes. Seismic performance evaluation of newly designed code-conforming structures is of interest, in order to identify any potential weaknesses and deficiencies in new structures that are designed with appropriate acceptable level of structural damage in the event of a design earthquake. The considered frames were evaluated for the significant damage limit state, for which the return period corresponds to the designed seismic actions. Nonlinear methods of analysis were used, which are the reference methods for assessing seismic performance. The frames designed for high class ductility manifested more favourable seismic performance and the frames designed for lower seismic action had lower values of demand/capacity ratio

Osnovni principi i pravila projektovanja, proračuna i izgradnje zidanih zgrada prema EC 6 i EC 8

Design of masonry structures implies a combination of traditional and contemporary knowledge. By introducing Eurocodes, their design is equated with the design of other type of structures. According to the division of contents of European standards for structural design, the Eurocode 6 provides general rules for design, while Eurocode 8 provides additional rules that should be taken into consideration in design of masonry structures for earthquake resistance. This paper provides a review of the most important provisions for the calculation and design concept for masonry structures in compliance with European standards EN 1996 and EN 1998. The basic design concept of masonry structures in seismically active areas is to allow the reduction of expected seismic activity within linear analysis which are obtained based on elastic response spectrum, where the level of design seismic forces depends on the adopted structural system and prescribed behavior of the structure during earthquakes.Projektovanje zidanih konstrukcija predstavlja kombinaciju tradicionalnih i savremenih saznanja, a uvođenjem Evrokodova izjednačava se njihovo projektovanje sa projektovanjem drugih tipova konstrukcija. Saglasno podeli sadržaja evropskih standarda za projektovanje konstrukcija, Evrokod 6 navodi opšta pravila za projektovanje, dok su u Evrokodu 8 data dodatna pravila koja treba uzeti u obzir pri projektovanju zidanih konstrukcija u seizmičkim uslovima. U radu je dat pregled najvažnijih odredbi za proračun i koncept projektovanja zidanih zgrada saglasno evropskim standardima EN 1996 i EN 1998. Osnovni koncept projektovanja višespratnih zidanih zgrada u seizmički aktivnim područjima ogleda se u tome da se u okviru linearne analize dozvoli redukcija očekivanih seizmičkih dejstava dobijenih na osnovu elastičnog spektra odgovora, pri čemu nivo redukcije seizmičkih sila zavisi od usvojenog konstrukcijskog sistema i propisanog ponašanja konstrukcije

Comparative Analysis of Seismic Response of Regular and Irregular Multi-Storey Frame Buildings

The aim of the paper is to assess the usability of nonlinear simplified methods for practical application for regular and irregular frame structure with different stories. The behaviour of regular and irregular, four and eight multi-storey RC frames, were analyzed using pushover analysis which allows for a more realistic estimation of seismic demands of multi-storey buildings. Nonlinear modeling and analysis allows more accurate determination of stresses, strains, deformations, internal forces and displacements of critical structural components, results that can then be utilized for the final design of the frame components or evaluation of the building global strength capacity and ductility. Numerical modelling of nonlinear behaviour is carried out by applying plastic hinges and the model with inelastic fibers. Estimation of target displacement is performed using capacity spectrum method, equivalent linearization method, coefficient method and displacement modification method. Comparative analysis of pushover curves obtained with plastic hinges model and structural model with inelastic fibers are performed

The estimation of seismic performances of reinforced concrete girder bridges using nonlinear dynamic analysis

varijantama konstrukcija grede mosta jeste kontinuirni nosač sa četiri polja (35 m + 50 m + 50 m + 35 m) i zglobno je oslonjena na vrhove stubova i krajnje oporce. Stubovi su potpuno uklješteni u tlo sa dužinama 7 m, 14 m i 21 m, tj. analizirano je 18 različitih kombinacija dužina stubova. Geometrijska nelinearnost se obuhvaća preko P–Δ efekta, a materijalna nelinearnost se uključuje u analize kroz vlaknaste modele plastičnih zglobova. Procjena seizmičkih performansi je izračunata na osnovu zahtijevane lokalne duktilnosti i kapaciteta lokalne duktilnosti koje posjeduju kritični poprečni presjeci u stubovima analiziranih varijanti mostova. Za nelinearne dinamičke analize upotrebljeni su umjetno (sintetički) generirani i realni zapisi zemljotresa.The paper applies nonlinear dynamic analysis to estimate seismic performances of reinforced concrete girder bridges. In all analysed variations, the structure of the beam implies the continual girder with four fields (35 m + 50 m + 50 m + 35 m) hinged to the pier tops and the abutments. The piers are completely fixed to the ground with the lengths of 7 m, 14 m and 21 m; hence, 18 diverse combinations of pier lengths have been analysed. Geometric nonlinearity is included via the P–Δ effect, while the material nonlinearity is included into the analyses using the fibre models of plastic hinges. The estimation of seismic performances has been calculated on the basis of the demanded local ductility and the local ductile capacity of the critical cross-sections in the piers of all bridge analysed variations. Artificially (synthetically) generated and recorded earthquake accelerograms have been utilized for nonlinear dynamic analyses

The Road Steel Bridge Over Bosut River in Serbia Part 1: The Assessment of the Bridge

AbstractMaintenance requirements for existing bridges outpace more and more available resources each day. Besides improved repair techniques, this situation emphasizes the need for a comprehensive approach to bridge management. An important activity in bridge maintenance is the inspection and assessment process, which includes determination of the general condition and structural safety of each bridge, as well as estimation of deterioration rates. Eventually, some idea of the structure repair can be determined. In this paper, the assessment of road steel bridge over Bosut river in Serbia was presented. During exploitation, numerous damages appeared on the bridge structural elements, mostly due to hundred years’ old exploitation and inadequate maintenance of the bridge. In order to evaluate the real condition of the bridge structure and possibilities for further exploitation, the assessment of the bridge was carried out. The assessment included: detailed visual inspection of all accessible elements with registration of characteristic defects and damages, evaluation of incorporated materials quality, determination of the depth of cracks in the river piers and structural calculation according to current regulations for road bridges loads. Based on the results of both field and laboratory tests, it was concluded that the durability of bridge structure is significantly reduced, due to advanced corrosion process of steel material

Fiber beam-column element implementation in academic CAD software Matrix 3D

Theoretical foundations of beam -column finite element implemented (and tested) within academic CAD software developed on FTN (Department of civil engineering) are presented in this paper. Aforementioned FE is force-based fibre element, divided into a discrete number of monitored sections. Besides of material nonlinearity, finite-element is capable of capturing geometrical nonlinearity. Some of numerical issues needed for performing incremental-iterative solution procedures with those elements are addressed in the paper. Finally, results and comparison with available data are shown

NDA TH mosta fundiranog na šipovima preko p-y krivih za pesak prema Reese-u

У раду je приказан прорачун моста коришћењем нелинеарне динамичке анализе (НДА) преко временске историје (ВИ) уз уважавање динамичке интеракције конструкција темељ тло. У систему тло-шип-конструкција, конструкција је моделована као оквирни систем са више степени слободе (МДОФ), тло је моделовано преко пе-ипсилон криви за песак као линк елементи, а према Рисовом моделу. Анализиран је редослед формирања пластичних зглобова у стубу, шипу и слом тла

Pile-Soil-Pile Interaction in Designing the Foundation of RC Structures

The paper analyzes the effects of pile-soil-pile interaction on the transverse bridge frame on specific example of building. It considers a small group of piles arranged in a single row. The columns are continuously set on piles over the RC blocks (raft beams). The typical pilesoil conditions were varied. Some phases of construction, typical of this type of calculation, have been included. The interaction was analyzed for homogeneous and linear elastic soil (semi-space), with some other models of analyzing pile-soil interaction were also indicated. The paper also presents redistribution of forces depending on the stiffness of the raft beams or superstructure. The calculation parameters were introduced in mathematical model using a simplified method