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This paper contains a proposed numerical procedure for determination of stress and deformations state due to creep and shrinkage of concrete and relaxation of prestressed steel in composite structures with apply of the finite element method. Stiffness matrix of linear finite-element is performed by use of layers technique, but rheological properties of concrete and prestressed reinforcement are introduced by fictive loading. For procedure development, generalized incremental stress-deformation links are used for viscous materials derived by application of displacement method. The manner is analysed in more details to determine fictive forces due to viscous deformations, especially the axial forces part as a contribution from the pure member bending. Improved procedure is formulated which provides considerable correction of results accuracy without the need of structure discretization on the bigger number of finite elements. Here developed procedure for calculation of composite structures is applicable in various technological procedures of construction-work with enabled gradual inclusion of some individual parts of composite section into a stress active section. It has been shown that time - dependent (rheological) changes considerably change state of stress and deformations of CS and that in their design negative impacts cannot be left out of the analysis. To that aim, the author has developed a program package with whose application, it is simple to get the needed results.

U ovom radu su analizirane osnovne metode projektovanja spregnutih greda od čelika i betona u zgradarstvu, u skladu sa Evrokodom. Analizirana su tri različita tipa čeličnih greda spregnutih sa betonskom pločom na profilisanom limu: greda u vidu klasičnog vruće valjanog I – profila, ''STUB'' sistemi spregnute grede i spregnuta greda sa "saćastim" čeličnim nosačem. Data je komparativna analiza primene tri sistema spregnutih greda. Poređenje je izvršeno i na numeričkom primeru nosača međuspratne konstrukcije javne garaže, raspona 15.50 m., This paper deals with main design methods for steel and concrete composite beams in buildings design, according to Eurocode. There were analyzed three different types of steel beam in combination with concrete slab on profiled steel sheet: standard hot rolled I - profile, composite STUB girder, and castellated composite beam. Comparative analysis of application of three solutions for composite beam was given. Numerical example is shown for structural elements of public car park floor structure , with 15.50 m span.

U ovom radu su analizirane osnovne metode projektovanja spregnutih greda od čelika i betona u zgradarstvu, u skladu sa Evrokodom. Analizirana su tri različita tipa čeličnih greda spregnutih sa betonskom pločom na profilisanom limu: greda u vidu klasičnog vruće valjanog I – profila, ''STUB'' sistemi spregnute grede i spregnuta greda sa "saćastim" čeličnim nosačem. Data je komparativna analiza primene tri sistema spregnutih greda. Poređenje je izvršeno i na numeričkom primeru nosača međuspratne konstrukcije javne garaže, raspona 15.50 m., This paper deals with main design methods for steel and concrete composite beams in buildings design, according to Eurocode. There were analyzed three different types of steel beam in combination with concrete slab on profiled steel sheet: standard hot rolled I - profile, composite STUB girder, and castellated composite beam. Comparative analysis of application of three solutions for composite beam was given. Numerical example is shown for structural elements of public car park floor structure , with 15.50 m span.

Different analytical methods, with different levels of approximations and accuracy, are available for analysis of continuous composite steel-concrete beams. The Eurocode 4 recommends few simple methods for calculation of creep, shrinkage, cracking of concrete and shear lag effects that are explained in the paper. Through the numerical examples of four continuous composite steel-concrete beams, the proposed methods of analyses are evaluated and compared. Practical recommendations for analysis of this type of girders are formulated., Za analizu spregnutih kontinualnih nosača od čelika i betona postoje različite analitičke metode, različitog stepena tačnosti. Evrokod 4 dozvoljava i preporučuje nekoliko jednostavnih metoda kojima se u proračun uvode nelinearni efekti kao što su skupljanje i tečenje betona, ispicalost betonske ploče i shear-lag efekat, i one su objašnjene u radu. Kroz numeričku analizu četiri spregnuta kontinualna nosača ove metode su upoređene i date su praktične preporuke za analizu ove grupe nosača.

Different analytical methods, with different levels of approximations and accuracy, are available for analysis of continuous composite steel-concrete beams. The Eurocode 4 recommends few simple methods for calculation of creep, shrinkage, cracking of concrete and shear lag effects that are explained in the paper. Through the numerical examples of four continuous composite steel-concrete beams, the proposed methods of analyses are evaluated and compared. Practical recommendations for analysis of this type of girders are formulated., Za analizu spregnutih kontinualnih nosača od čelika i betona postoje različite analitičke metode, različitog stepena tačnosti. Evrokod 4 dozvoljava i preporučuje nekoliko jednostavnih metoda kojima se u proračun uvode nelinearni efekti kao što su skupljanje i tečenje betona, ispicalost betonske ploče i shear-lag efekat, i one su objašnjene u radu. Kroz numeričku analizu četiri spregnuta kontinualna nosača ove metode su upoređene i date su praktične preporuke za analizu ove grupe nosača.

Postoji veliki broj primenjenih rešenja u projektovanju višespratnih garaža: različita konstrukcijska rešenja razlikuju se u načinu na koji se projektuju međuspratne konstrukcije. Primena spregnutih konstrukcija u projektovanju međuspratnih konstrukcija rezultuje: smanjenjem utroška čelika, smanjenjem građevinske visine, kraćim vremenom građenja. U ovom radu su analizirane osnovne metode projektovanja spregnutih greda od čelika i betona, u skladu sa Evrokodom. Analizirana su tri različita tipa čeličnih greda spregnutih sa betonskom pločom na profilisanom limu: greda u vidu klasičnog vruće valjanog I - profila, STUB sistemi spregnute grede i spregnuta greda u vidu saćastog čeličnog nosača. Data je komparativna analiza primene tri sistema spregnute grede. Usvojeno rešenje primenjeno je u konstrukciji koja je opisana u drugom delu ovog rada. U drugom delu rada je detaljno izložen proračun noseće čelične konstrukcije javne garaže dimenzija 31x70 m u osnovi, spratnosti P+3, sa detaljima čelične konstrukcije., There is a great variety of applied solutions in multi-storey car parks design: the various construction types differ from one another by the way the floors are built. Applying of composite structures in floor design results in: reduction in steel consumption, reduction of the structural height, shorter construction period. This research deals with main design methods for composite beam from steel and concrete, according to Eurocode. There were analyzed three solutions for steel beam in combination with concrete slab on profiled steel sheet: standard hot rolled I - profile, composite Stub girder, and castellated composite beam. Comparative analysis of application of three solutions for composite beam was given. The admited solution is applied in the construction of which is described in the second part of this paper. The second part of this paper is exposed to the detailed calculation of main steel construction of public car park, with dimensions of 31x70 m in the basis, with B+3 floors, and with structural steel detailing.

In this paper, the analysis of longitudinal shear in concrete slab, according to Eurocode 4 (EN 1994-1-1:2004), is shown. The potential surfaces of shear failure in solid and composite slab are analyzed. For each potential surface of shear failure, the corresponding length is defined. The transverse reinforcement should be determined from the condition that, for any potential surface of shear failure, the design longitudinal shear per unit length (shear flow) is not greater than the longitudinal shear resistance of the slab per unit length. The longitudinal shear resistance of concrete slab per unit length should be determined according to EN 1992-1-1. The rules for transverse reinforcement are based on a truss analogy, i.e. the concrete slab is considered as a truss system that has compressed concrete struts and tensioned reinforcement (chords).The failure occurs when either the reinforcement yields or the concrete struts fail in compression. The transverse reinforcement in the concrete slab transfers the shear stresses from studs (shear connectors) and ensures that the premature failure of the slab will not occur., U radu se prikazuje proračun podužnog smicanja u betonskoj ploči prema Evrokodu 4 (EN 1994-1-1:2004). Analiziraju se potencijalne površine loma usled podužnog smicanja, u punoj i spregnutoj betonskoj ploči. Za svaku potencijalnu površinu loma definiše se odgovarajuća dužina površine smicanja. Proračun nosivosti pri podužnom smicanju se zasniva na uslovu da proračunski podužni napon smicanja, bilo koje potencijalne površine loma usled podužnog smicanja u okviru ploče, ne bude veći od proračunske nosivosti pri podužnom smicanju. Proračunska nosivost pri podužnom smicanju betonske ploče se određuje u skladu sa EN 1992-1-1. Ovaj proračun se zasniva na modelu rešetke, tj. betonska ploča se posmatra kao sistem kosih (dijagonalnih) pritisnutih betonskih štapova kombinovan sa zategama koje predstavlja poprečna zategnuta armatura. Gubitak nosivosti (lom) betonske ploče nastaje ako dođe do tečenja (loma) u armaturi ili ako dođe do drobljenja betona u pritisnutim štapovima. U betonskoj ploči se obezbeđuje adekvatna površina poprečne armature koja će da prenese smičuće napone iz moždanika i obezbedi da ne dođe do prevremenog loma u betonu.

Postoji veliki broj primenjenih rešenja u projektovanju višespratnih garaža: različita konstrukcijska rešenja razlikuju se u načinu na koji se projektuju međuspratne konstrukcije. Primena spregnutih konstrukcija u projektovanju međuspratnih konstrukcija rezultuje: smanjenjem utroška čelika, smanjenjem građevinske visine, kraćim vremenom građenja. U ovom radu su analizirane osnovne metode projektovanja spregnutih greda od čelika i betona, u skladu sa Evrokodom. Analizirana su tri različita tipa čeličnih greda spregnutih sa betonskom pločom na profilisanom limu: greda u vidu klasičnog vruće valjanog I - profila, STUB sistemi spregnute grede i spregnuta greda u vidu saćastog čeličnog nosača. Data je komparativna analiza primene tri sistema spregnute grede. Usvojeno rešenje primenjeno je u konstrukciji koja je opisana u drugom delu ovog rada. U drugom delu rada je detaljno izložen proračun noseće čelične konstrukcije javne garaže dimenzija 31x70 m u osnovi, spratnosti P+3, sa detaljima čelične konstrukcije., There is a great variety of applied solutions in multi-storey car parks design: the various construction types differ from one another by the way the floors are built. Applying of composite structures in floor design results in: reduction in steel consumption, reduction of the structural height, shorter construction period. This research deals with main design methods for composite beam from steel and concrete, according to Eurocode. There were analyzed three solutions for steel beam in combination with concrete slab on profiled steel sheet: standard hot rolled I - profile, composite Stub girder, and castellated composite beam. Comparative analysis of application of three solutions for composite beam was given. The admited solution is applied in the construction of which is described in the second part of this paper. The second part of this paper is exposed to the detailed calculation of main steel construction of public car park, with dimensions of 31x70 m in the basis, with B+3 floors, and with structural steel detailing.

In this paper, the analysis of longitudinal shear in concrete slab, according to Eurocode 4 (EN 1994-1-1:2004), is shown. The potential surfaces of shear failure in solid and composite slab are analyzed. For each potential surface of shear failure, the corresponding length is defined. The transverse reinforcement should be determined from the condition that, for any potential surface of shear failure, the design longitudinal shear per unit length (shear flow) is not greater than the longitudinal shear resistance of the slab per unit length. The longitudinal shear resistance of concrete slab per unit length should be determined according to EN 1992-1-1. The rules for transverse reinforcement are based on a truss analogy, i.e. the concrete slab is considered as a truss system that has compressed concrete struts and tensioned reinforcement (chords).The failure occurs when either the reinforcement yields or the concrete struts fail in compression. The transverse reinforcement in the concrete slab transfers the shear stresses from studs (shear connectors) and ensures that the premature failure of the slab will not occur., U radu se prikazuje proračun podužnog smicanja u betonskoj ploči prema Evrokodu 4 (EN 1994-1-1:2004). Analiziraju se potencijalne površine loma usled podužnog smicanja, u punoj i spregnutoj betonskoj ploči. Za svaku potencijalnu površinu loma definiše se odgovarajuća dužina površine smicanja. Proračun nosivosti pri podužnom smicanju se zasniva na uslovu da proračunski podužni napon smicanja, bilo koje potencijalne površine loma usled podužnog smicanja u okviru ploče, ne bude veći od proračunske nosivosti pri podužnom smicanju. Proračunska nosivost pri podužnom smicanju betonske ploče se određuje u skladu sa EN 1992-1-1. Ovaj proračun se zasniva na modelu rešetke, tj. betonska ploča se posmatra kao sistem kosih (dijagonalnih) pritisnutih betonskih štapova kombinovan sa zategama koje predstavlja poprečna zategnuta armatura. Gubitak nosivosti (lom) betonske ploče nastaje ako dođe do tečenja (loma) u armaturi ili ako dođe do drobljenja betona u pritisnutim štapovima. U betonskoj ploči se obezbeđuje adekvatna površina poprečne armature koja će da prenese smičuće napone iz moždanika i obezbedi da ne dođe do prevremenog loma u betonu.