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The steel structures of canopies, public garage columns, street lighting, power lines and other street furniture are constantly exposed to weather effects in their service life. The steel structure of street furniture is often exposed to the effects of de-icing salts from the roads. The paper analyses the effects of the urban environment on the durability of steel structures. The macroscopic visual inspection included 181 steel billboard poles on the territory of the City of Belgrade. The analysis of the surface treatment, the condition of the structure and its location provided conclusions regarding the durability of steel structures in urban environments. The environmental corrosivity on the territory of the City of Belgrade has been analysed. The analysis included the bearing steel structure of poles and the joint between the steel structure and foundations., Čeličnu konstrukciju nadstrešnica, stubova javnih garaža, ulične rasvete, dalekovoda i drugog urbanog mobilijara karakteriše stalna izloženost atmosferskim uticajima tokom životnog veka. Čelična konstrukcija urbanog mobilijara je neretko izložena i uticaju soli za održavanje saobraćajnica. U radu je analiziran uticaj gradske sredine na trajnost čelične konstrukcije. Stručnim vizuelno-makroskopskim pregledom obuhvaćen je 181 stub čelične konstrukcije za nošenje reklamnih medija na teritoriji grada Beograda. Analizirajući vrstu antikorozione zaštite, stanje konstrukcije i lokaciju konstrukcije izvedeni su zaključci o trajnosti čelične konstrukcije u urbanoj sredini. Analiziran je i stepen korozivnosti sredine na teritoriji grada Beograda. Analiza je obuhvatila noseću čeličnu konstrukciju stubova i detalj veze čelične konstrukcije i temelja.

When analysing the fire resistance of the steel structure of the stadium roof in the event of a fire, the specific features of the stadium building must be taken into consideration. The stadium stands are open units of the building that are directly connected to the surrounding area. The clear height between the stadium roof and the stands is commonly large. However, the clear height between relatively small parts of the roof, directly above the top of the stands, could be smaller, potentially making this part of the roof the most vulnerable. On the stands of the stadium, it is prohibited to bring items that contain combustible material. In addition, the structure of the stadium, benches or chairs must be made of non-combustible material. Therefore, a fire that could compromise the steel structure of the stadium roof can only come from the stadium premises on the stands or under the stands. The fire scenarios on the stadium roof are not described in detail in the literature compared to indoor (covered) sports arenas. To assess the fire resistance of the roof structure, it is necessary to check all possible and potentially dangerous scenarios. The subject of the analysis presented in this paper is the roof steel structure of the stadium in Loznica, Serbia, which was built in the period 2021–2023. The study considers the following fire scenarios and their effects on the roof steel structure: (i) a local fire on the stands, and (ii) a fire in the stadium premises affecting the external members. The fire in stadium premises was analysed using the analytical expressions provided in Annex B of EN 1991-1-2 and EN 1993-1-2, as well as through CFD (Computational Fluid Dynamics) analysis of fire propagation. The calculation was performed for the domains of temperature, time and resistance, depending on the applied fire load analysis. Results showed that the steel structure of the stadium roof in Loznica meets the load-bearing codified criteria for the fire effects, with the e

Ground floors of industrial buildings, fully supported on the ground or piles, are usually made of several concrete segments connected through free-movement construction joints. These joints should provide shear load transfer of the slab and minimise its vertical displacements while allowing slab horizontal movement to prevent damage due to concrete dry shrinkage. The construction joint “Dilat 08”, consisting of round steel dowels and steel formwork, was experimentally tested in a laboratory environment to determine its behaviour to shear load. The experimental double-shear setup consisted of three slabs connecting through the “Dilat 08” join system, with two side slabs fully supported on the base and the middle slab on which the vertical loading was applied. Specimens were formed with a gap of 10 mm between adjacent slabs to simulate the construction joint opening. Two construction joint orientations were investigated introducing the vertical load to the slab with a steel plate on the edge and to the slab with an angle profile on the edge. Experimental testing of both specimens resulted in construction joint failure due to concrete cracking around steel dowels, near the edges of the middle slab. The investigation confirmed that the joint orientation affects the joint shear response, demonstrating larger joint resistance when the steel plate is installed in the slab subjected to failure. Although contributing to the joint bending stiffness before formwork installation on the site, the horizontal leg of the angle profile decreases the joint resistance. Experimentally obtained joint resistance was compared to the design values of resistance according to Technical Report 34 and EN 1992- 4, highlighting a considerable difference between the two analytical approaches. The comparison between the “Dilat 08” and three types of free-movement joints available on the construction market showed that “Dilat 08” features larger resistance according to Technical Report 34, but it

Nowadays, numerous experimentally, numerically and analytically based research have been performed to evaluate the structural responses and ultimate capacity of beams with web openings, but mostly under bending. However, in practice, the application of steel cellular elements dominantly loaded by axial pressure is very common. With the lack of appropriate design approaches, we rely on engineering judgement, which can result in uneconomic, time- consuming, or unsafe solutions. To ensure the safety of a structure it is necessary to assess its structural resilience. An overview of the existing experimental study on compressed I-section short columns with web openings, assessment of the impact of openings’ size and shape on cross-section deformation and resistance capacity under pure compression was performed. To accomplish an adequate and easy-to-use design method for hot rolled perforated columns, the design procedures stated in: (i) draft version of new European code prEN 1993-1-13, (ii) the Direct Strength Method (DSM) in American standard AISI S100-16 and (iii) the Continuous Strength Method (CSM) in prEN 1993-1-4 were evaluated based on experimental data, and the obtained outcomes are briefly presented in this paper. Although none of these design methods include all aspects of observed case – hot rolled perforated elements under compression (Eurocode has a strict limit of axial force, CSM and DSM primarily refer to cold-formed steel sections and do not recognize the existence of openings at all), they turned out to be quite accurate. The corresponding results were obtained by modifying those procedures, so they better reflect a case of interest. Thus, DSM method didn’t need any modifications, and CSM had the most.

Following the trend of sustainable development and structure reuse, many novel solutions related to demountable shear connectors for application in steel-concrete composite beams have been proposed in recent years. This paper provides a further contribution to the research field by proposing a demountable connection with bolts and welded headed studs. The transfer of shear force between a steel flange and a composite concrete slab cast in an open trough profiled steel sheeting is indirect, passing through a steel plate or angles. The proposed solution enables convenient dismantling and reuse of both the composite slab and the steel profile. The experimental investigation included push-out tests, performed to assess the connection shear behaviour, determine resistance and ductility, and identify failure modes. Various configurations of the demountable connection were analysed, including connections with continuous and discontinuous slabs over the support. The response of the suggested demountable solution was compared to the corresponding non-demountable shear connection with headed studs. According to experimental investigation, finite element models were developed, and their accuracy was validated by comparing numerical predictions with experimental results. Parametric studies were conducted using numerical models to evaluate the effects of key parameters on the connection performance, such as plate and angle thickness, stirrup reinforcement position, and transverse distance between a headed stud and slab edge. Directions for design were proposed taking into account the results obtained.

In the past few decades, demountable connectors have often been used for connections in composite and mixed steel-concrete structures to reduce construction time and costs. Furthermore, the application of demountable connectors enables the reuse of structural elements in these structures, which leads to sustainable design and a circular economy. In this paper, the demountable connector is made out of two parts: (1) mechanical coupler and rebar anchor placed in formwork before casting the concrete element, and (2) steel bolt used for connecting steel to the RC element. Although this connector is increasingly being used in contemporary building structures, its behaviour in composite connections is still insufficiently defined. The paper presents the results of experimental tests and numerical analysis of the connector with a mechanical coupler, focusing on the local behaviour of the tapered threaded connection between the mechanical coupler and rebar anchor.

Cartridge fired pins, also known as powder actuated fasteners, have a wide application in different construction industry fields, mostly for joints of cold-formed structural elements and profiled steel sheeting, or for installation of shear connectors in composite steel-concrete structures. Installation of cartridge fired pins is mostly governed by high energy introduction from installation device and mechanical fastener to the steel base material, without initial predrilling of holes. Therefore, large plastic deformations of base material are developed through installation procedure, together with various anchorage mechanisms between fastener and base material. This paper presents experimental investigation of most important influence parameters on behaviour and resistance of cartridge fired pins, such as adjusted installation power level on installation device and steel base material strength. Experimental investigation involved X-ENP-21 HVB cartridge fired pins through double-sided shear tests, tension tests with fasteners installed over X-HVB shear connector with two different steel grades (S275 and S355) and two installation power levels (2 and 3.5), and tension tests with fasteners installed over two thicknesses of pro-filed steel sheeting (0.8 mm and 1.0 mm). Cartridge fired pin resistances together with corresponding failure mechanisms were experimentally quantified and presented in this paper.

Implementation of demountable beams in steel-concrete composite floors enables structure reuse during several life cycles, consequently leading to savings in material consumption and reduction of emissions, providing overall ecological benefits. The behaviour of the innovative demountable beam with a shear connection consisting of headed studs and bolts is analysed in this paper. The proposed beam is formed of a steel profile and a steel-concrete composite slab cast in open trough profiled steel sheeting. Headed studs, welded to the additional steel angles, are placed in sheeting ribs, whereas bolts are installed between ribs, connecting the steel angles and profile flange. A numerical FE model of a full-scale steel-concrete composite beam has been developed to analyse the beam behaviour under service loads. Experimental results of push-out tests have been used to describe the loadslip behaviour of headed studs, whereas bolt response has been simulated according to the experimental investigations of lap joints with preloaded bolts and oversize holes. The parametric study has been conducted by varying the bolt diameter, grade and bolt hole size. The results have validated the applicability of the proposed system, confirming the fulfilment of serviceability limit state requirements.

Push-out tests are commonly used to investigate the shear performance of mechanical connectors applicable in steel-concrete composite beams. These tests can be complemented by numerical finite element simulations to reduce the need for extensive experimental testing. After validation against experimental results, numerical models could be used for additional analysis and parametric studies. The development of finite element models of push-out tests requires special attention to be put on modelling concrete behaviour, especially if concrete failure is the dominant failure mode. The concrete damage plasticity (CDP) models, combining plasticity and damage mechanics to represent the nonlinear behaviour of concrete, are commonly applied. This paper summarises and presents four different CDP models that have been successfully used by researchers in finite element simulations of push-out tests. The applicability of different models has been discussed in the specific case of shear connection with headed studs in profiled steel sheeting with a varied angle between profiled sheeting ribs and the beam. Results of comparative analysis are presented, indicating a significant influence of the applied CDP model on the response of push-out specimen. The best match between experimental and numerical results is accomplished by implementing the material model proposed by Pavlović with calibrated input parameters. Nevertheless, the applicability of each CDP model depends on the specific problem that is being analysed and therefore should be carefully approached.

Three advanced fire models for structural design are defined in Eurocode: one-zone model, two-zone model and model based on Computational Fluid Dynamics (CFD). This paper describes the effects on structures exposed to fire, based on the CFD model. The advanced computational fluid dynamics model was used to define the thermal action and temperature of the structural steel elements on the analysed case study object, open multi-storey car park Obilićev Venac in Belgrade. The support structure of the car park is a typical composite floor structure with steel columns. Distance between the columns and the floor beams corresponds to the dimension of one parking slot. The maximum temperature values of steel structural elements that occur during a fire are investigated. Based on the results of the tests available in the literature, CFD fire load models were created. Two different fire loads are used in numerical simulations. The first one is the fire load model based on combustible materials, which simulate the typical modern small car weighing up to one tonne. In the second case, the fire loads model was described with the Heat Release Rate (HRR) curve. Two of the referenced HRR curves defined by the French CTICM and Netherlands TNO Institute are used in CFD models. The discussion in this paper is limited to fire cases with one burning car. The parametric study considered the dimensions and positions of the burner element in the model. The effects of the natural ventilation in the open car park during the fire were also investigated. The presented results are from the Research project “Advanced structures design – fire safety guideline for V4” funded by the Višegrad fund. A joint effort of colleagues from Hungary, Czech Republic, Slovakia, Poland and Serbia, produced the project report, which described five different case studies.

Eurocode introduces innovations in the design of steel structures that create new opportunities for designers and contractors to construct more attractive and cost-effective structures. The paper present a new approach to designing steel structures based on advanced methods defined in Eurocode. These methods were not recognised by the old ex Yugoslav steel structures codes. Advanced numerical simulations are a powerful tool that helps engineers understand the deformation and stresses of the structure in detail. Possibilities of high-end design software in the application of GMNIA (Geometrically and Materially Nonlinear Analysis with Imperfections) in the design of complex elements of steel structures will be demonstrated. The authors will illustrate the application of finite element methods of analysis based on Eurocode on practical examples. Buckling limit state and calculation of design resistance of the cylindrical shell with the opening will be shown. On the example of a pedestrian bridge, the stability of plated structural members with web opening will be analysed. The examples of steel girder frames will illustrate the application of global and local imperfections in calculating the design resistance of the structural steel members. The comparison between methods for the design of frame structure is done on the example of the two-storey frame structure. The paper briefly reviews the most important novelties brought about by Eurocode 3 for steel structures. A review of the new advanced design methods in the next edition of the Eurocode for steel structures will be given.

Headed studs are the most commonly used mechanical shear connectors in composite steel-concrete beams. The behaviour of headed studs differs whether they are applied in solid concrete slabs or composite steel-concrete slabs with profiled steel sheeting. Although design codes provide calculation models for shear resistance of headed studs in profiled steel sheeting, certain weaknesses are attributed to design procedures given in EN 1994-1-1. Alternative design models have been proposed by several researchers. In this paper, novel models are presented and compared through the example of headed studs in different types of profiled steel sheeting., Moždanici sa glavom su najčešće primenjivana mehanička spojna sredstava u spregnutim gredama od čelika i betona. Ponašanje moždanika razlikuje se u zavisnosti od toga da li se primenjuju u punim betonskim pločama ili u spregnutim pločama na profilisanom limu. Iako su proračunski modeli za nosivost moždanika u profilisanom limu dati u standardima za projektovanje, važećim proračunskim procedurama datim u EN 1994-1-1 pripisuju se izvesni nedostaci. Iz tog razloga nekoliko istraživača je predložilo alternativne proračunske modele. U radu su prikazani predloženi modeli proračuna i data je uporedna analiza nosivosti moždanika sa glavom u različitim tipovima profilisanog lima.

Reconstruction of the Sava Centre in Belgrade, a cultural good of the Republic of Serbia, includes works on the facility, ensuring that the congress centre's construction meets all modern requirements for fire protection. The paper presents the design fires used to conduct fire resistance design of the steel structure of the roof and facade. By applying analytical procedures defined in Eurocodes for structures and performing advanced CFD analysis, it has been shown that most of the purlins in Building A of the Sava Centre satisfy the required 60 minutes of fire resistance. This paper also presents the calculation of the fire loads applied in design fires., Rekonstrukcija Sava Centra u Beogradu, kulturnog dobra Republike Srbije, podrazumeva radove na objektu, koji moraju da obezbede da konstrukcija kongresnog centra ispunjava sve savremene zahteve protivpožarne zaštite. U radu su prikazni proračunski požari korišćeni za dokaz otpornosti na dejstvo požara čelične konstrukcije krova i fasade. Primenom analitičkih postupaka definisanih u Evrokodovima za konstrukcije i napredne CFD analize pokazano je da veći deo rožnjača u bloka A Sava Centra zadovoljava nosivost pri dejstvu požara u trajanju od 60 minuta. Sračunavanje požarnih opterećenja pri definisanju proračunskih požara takođe je prikazano u ovom radu.

Multi-storey car park buildings with steel–concrete composite floor structures are widespread in construction due to the distinct benefits of the implemented structural system. Although there are various possibilities for accomplishing composite action between a steel beam and a concrete slab, some solutions, such as friction-grip bolts commonly applied in the 1970s, did not show good durability. An example is the multi-storey car park building “Obilićev venac” in Belgrade. This case study presents two methods for life extension of the car park building structure. Both approaches focus on applying welded headed studs with the primary intention of providing a durable shear connection. While the first method has been applied during the structure’s reconstruction, the second method is proposed as a novel solution for implementation in steel–concrete composite floors. The application of the proposed connection is discussed and the results of the experimental and numerical research conducted are presented.

For obtaining shear resistance of a welded headed stud in profiled steel sheeting, EN 1994-1-1:2004 defines reduction factors that should be multiplied with the resistance of a headed stud in a solid concrete slab. Two reduction factors are prescribed, for sheeting ribs that are parallel and transverse to the supporting beam. However, the design code does not recognise cases when the angle between ribs and the beam is in the range between 0° and 90°. This research is focused on the specific case in the steel-concrete composite beam design when the angle between profiled sheeting ribs and the beam is 45°. The experimental investigation has been conducted through push-out tests, comparing the response of the connection with a rib-to-beam angle of 45° and the connection with ribs transverse to the supporting beam. In addition, numerical models based on finite element analysis have been made and validated against experimental data. According to the obtained results, similar failure mechanisms manifested through concrete pull-out failure and separation of the concrete cone are observed in shear connections with rib-to-beam angles of 45° and 90°. An increase in the connection resistance is noticed with the decrease of a rib-to-beam angle.

During the assembling of a steel structure with anchors, grout should be used in connections be- tween steel elements and a reinforced concrete support element. In horizontal and vertical joints, grout is used as a good construction practice for solving geometric tolerance problems. Grout can be used with cast-in anchors or post-installed anchors. However, the relation between anchor shear resistance and characteristic grout compressive strength is not described in detail in tech- nical regulations. The behaviour of a connection considering achieved slip tolerances should match the boundary conditions set in the global analysis. In the support joint, grout properties could influence the value of the slip between a steel part and a concrete part of the joint. Slip value could be significant for the relevant design cases featuring the interaction of shear force and ten- sion force. In this paper, results of the push-out test conducted on anchors are presented. Based on the experimental test, the finite element analysis was performed to investigate the shear con- nection behaviour. According to the preliminary results, it can be concluded that a grout strength and a grout thickness influence the connection response when serviceability loads are applied, alt- hough they do not influence the ultimate load bearing capacity of anchors. In some cases, using the contemporary solutions of high strength grout materials, the slip between steel and concrete parts in the connection could be reduced.

Modern conustructions of pedestrian bridges must satisfy functional and increasingly complex architectural requirements. In order to achieve the attractive design of pedestrian bridges, modern constructions generally differ from older, conventional solutions. The vibration problem of such structures shows that the dynamic response of the structure is governing for the design. This paper presents the comparative analysis of several dynamic models of pedestrian loads, described in various standards, guidelines, and recommendations. On the example of an arched pedestrian bridge, comparative analysis of the structure behavior due to the effect of pedestrian load was performed using numerical simulations in the SOFISTIK software, with the results obtained by analytical calculation procedures.

In keeping with current demands for sustainable development in all segments of the industry, numerous research in the field of steel-concrete composite structures has been focused on developing demountable shear connectors. In the past years, various demountable shear connectors have been suggested, with various mechanisms for transferring shear force between a steel profile and a concrete or composite slab. In this paper, a state of the art on the topic is given, and experimental and numerical research results of push-out and beam tests are summarized., U skladu sa zahtjevima za održivi razvoj u svim segmentima industrije, brojna su istraživanja u području spregnutih čelično-betonskih konstrukcija usmjerena na razvoj demontažnih sredstava za sprezanje. Proteklih godina predlagana su različita demontažna sredstva za sprezanje koja su različitim mehanizmima prenosila posmičnu silu između čeličnog profila i betonske ili spregnute ploče. U ovom radu prikazana su najnovija dostignuća na tu temu dajući sažetke eksperimentalnih i numeričkih rezultata istraživanja vezano uz potisna (push-out) ispitivanja i ispitivanja na nosačima.

Human perception of floor vibrations and uncompromised serviceability of equipment are two most important acceptability criteria considering floor vibrations. While verification of deflection is a simple and well-known procedure in structures’ design for serviceability limit state, the fulfilment of floor vibrations acceptability criteria are presented in different standards in the form of various calculation procedures. Results achieved through those calculation procedures are presented in the form of various classification of floor structures. Classification of composite floor structures due to vibrations is inconsistent considering different calculation procedures. Comparison of various calculation procedures for the definition of composite floor vibrations is presented in this paper. In addition, a parametric analysis is performed on the wide range of steel-concrete composite floor structures, through analysis of various composite floor layouts and a wide range of imposed loads values. The analysis of the relation between deflection, vertical vibrations and accelerations of steel-concrete composite floor beams is presented in this paper. The results of the parametric analysis are given through direct relation between deflections of composite beams and achieved floor class for the fulfilment of vibrations acceptability criteria due to the pedestrian walking.

This paper will focus on fixed roof storage tanks and its sub-category cone roof tanks. Paper presents major factors and outputs of tank design process. Theoretical analysis is done for a cone roof tank model and correlation between tank surface, shell thickness and total steel weight used. Detailed algorithm for tank design was realized using MathCAD software using Eurocode standards. Using this algorithm, 432 hypothetical tanks were designed. Data analysis of the collected output data was analysed using R statistics programming language. Using regression models and testing them led to the optimum statistical model. For the purpose of this work, data for 21 real world tanks including fixed roof and floating roof tanks were collected. The data was collected with help of MOL, INA and few other EPC contractors. Paper compares real world data with outputs of the model. Model can be used for quick estimates and control of material consumptions. Taking few input parameters and applying minimal effort can lead to a very accurate steel consumption prediction. With additional real-world data, acceptable ranges of deviation from the mean could be set-up. Thus, allowing for better control on Client part or EPC companies.

Nowadays, in prefabricated composite construction, composite action between steel beam and concrete slab is often achieved with positioning of shear connectors in envisaged openings of concrete slabs. Prefabricated concrete slabs are used for composite steel-concrete buildings and bridges, both for the construction of new structures and for renovation of existing ones, significantly reducing construction time. Development of different types of shear connectors represent alternative solution to the traditionally used headed studs, considering their shear resistance, stiffness and ductility. New types of shear connectors tend to reduce the construction time and overall construction cost. Mechanically fastened shear connectors represent a viable alternative to headed studs, considering their fast installation process and shear resistance. X-HVB shear connectors are attached to the steel beam with two cartridge fired pins. The first step towards extensive implementation of X-HVB shear connectors in composite construction is to understand their behaviour through experimental investigation. Results of the push-out tests, in accordance to Eurocode 4, with X-HVB 110 shear connectors positioned in envisaged openings of prefabricated concrete slabs are presented in this paper. The experimental investigation comprised three different specimen’s layout. Group arrangement of X-HVB shear connectors in envisaged openings included specimens with minimal recommended distances and specimens with reduced distances between connectors in both directions. Influence of different installation procedures on overall behaviour of the connection is presented, as well as the orientation of shear connectors relative to the shear force direction. Influence of variations is characterized in terms of failure mechanisms, shear resistance and ductility.

Savremeni trendovi u građevinarstvu u oblasti spregnutih konstrukcija od čelika i betona najčešće se ogledaju u povećanim zahtevima za ubrzanom gradnjom, razvojem novih vrsta sredstava za sprezanje i prefabrikovanom gradnjom. Mehanički spojena sredstva za sprezanje predstavljaju alternativu tradicionalno korištenim zavarenim moždanicima sa glavom. Veza ovakvih sredstava za sprezanje sa čeličnim nosačima ostvaruje se pomoću različitih mehaničkih spojnih sredstava koji se ugrađuju procesom eksplozivnog upucavanja. U literaturi se ova mehanička spojna sredstva najčešće označavaju kao ekseri sa eksplozivnim upucavanjem. Mehanički spojena sredstva za sprezanje čine jedinstven sistem formiran od samog sredstva za sprezanje, odnosno moždanika i mehaničkog spojnog sredstva, odnosno eksera. Stoga je njihovo ponašanje u spregnutim konstrukcijama u direktnoj vezi sa ponašanjem eksera sa eksplozivnim upucavanjem. Za razliku od zavarenih moždanika sa glavom ili zavrtenjeva kao sredstava za sprezanje koji se često koriste u zgradarstvu, ponašanje mehanički spojenih sredstava za sprezanje u literaturi nije još uvek detaljno objašnjeno. U ovom radu dat je prikaz X-HVB moždanika kao najpoznatijeg predstavnika mehanički spojenih sredstava za sprezanje. Objašnjeno je njihovo ponašanje u spregnutim konstrukcijama i prikazane su osnovne karakteristike eksera sa eksplozivnim upucavanjem.

New demands towards fast construction resulted in development of different types of prefabricated concrete slabs and shear connectors. Composite action between steel beam and concrete slabs can be achieved with group positioning of shear connectors in envisaged openings of prefabricated concrete slabs. The aim of presented investigation is to promote application of mechanically fastened shear connectors in prefabricated concrete slabs. X-HVB 110 shear connectors fastened to the steel base material with X-ENP-21 HVB cartridge fired pins are used in experimental and numerical analysis presented in this thesis. Presented investigation should improve understanding of X-HVB shear connectors behaviour which is currently based on their application in solid or composite concrete slabs. Also, this investigation should result in extension of currently small basis of experimental results, which are mostly part of the technical reports and are considered as proprietary. Feasibility study presented in this work highlighted the importance of further investigation of X-HVB shear connectors in group arrangement, at distances smaller than minimal recommended, in order to satisfy current recommendations for minimal partial shear connection degree in composite floor structures with profiled steel sheeting. Detail examination of X-HVB 110 shear connectors positioned in envisaged openings of prefabricated composite slabs is performed. The experiment aims at understanding the effects of the spacing between shear connectors, orientation of shear connectors relative to the shear force direction and installation power level used for installation of cartridge fired pins, when they are used for prefabricated composite construction. In order to generate all structural performance data, this investigation included experimental investigation of cartridge fired pins performed through shear and tension tests. Extensive finite element analysis is conducted in this research in order to develop and c, Савремени трендови у грађевинарству се најчешће огледају у повећаним захтевима за убрзаном градњом, што је утицало на развој нових вртса префабрикованих бетонских плоча и средстава за спрезање. Спрезање префабрикованих бетонских плоча и челичних гредних носача најчешће се постиже постављањем можданика у отворе у бетонској плочи, који су за то предвиђени у процесу префабрикације. Предмет научног истраживања је понашање смичућих спојева остварених помоћу X-HVB можданика у префабрикованим бетонским плочама. X-HVB 110 можданици повезани су са челичним профилима уз помоћ два X-ENP-21 HVB механичка спојна средства (ексера) експлозивним упуцавањем. Приказано испитивање треба да допринесе бољем разумевању понашања X-HVB можданика у смичућим спојевима, које је тренутно засновано на испитивањима у пуним и спрегнутим бетонским плочама на профилисаним лимовима. Такође, испитивање треба да допринесе проширењу тренутно мале базе експерименталних испитивања, којa су највећим делом садржанa у техничким извештајима који нису лако доступни истраживачима. Упоредна анализа носивости заварених можданика са главом и X-HVB можданика у спрегнутим плочама са профилисаним лимом, презентована у овом раду, нагласила је потребу за додатним испитивањима ове врсте можданика када су они груписани на растојањима која су мања од минимално препоручених, како би се задовољиле тренутне препоруке у погледу минималног процента парцијалног смичућег споја. Детаљно експериментално испитивање X-HVB 110 можданика постављених у отворе префабрикованих бетонских плоча спорведно је у овом раду. Испитивање је обухватило утицај положаја и међусобног растојања можданика у односу на правац смичуће силе као и различите јачине уградње ексера. У циљу јасног сагледавања понашања ове врсте можданика, експеримeнтално испитивање ескера је спроведено кроз тестове смицања и затезања. Нумерички модели базирани на методи коначних елемената развијени су за потребе симулирања смичућих спојева са X-HVB 110 можданицима као и ескера

New demands towards fast construction resulted in development of different types of prefabricated concrete slabs and shear connectors. Composite action between steel beam and concrete slabs can be achieved with group positioning of shear connectors in envisaged openings of prefabricated concrete slabs. The aim of presented investigation is to promote application of mechanically fastened shear connectors in prefabricated concrete slabs. X-HVB 110 shear connectors fastened to the steel base material with X-ENP-21 HVB cartridge fired pins are used in experimental and numerical analysis presented in this thesis. Presented investigation should improve understanding of X-HVB shear connectors behaviour which is currently based on their application in solid or composite concrete slabs. Also, this investigation should result in extension of currently small basis of experimental results, which are mostly part of the technical reports and are considered as proprietary. Feasibility study presented in this work highlighted the importance of further investigation of X-HVB shear connectors in group arrangement, at distances smaller than minimal recommended, in order to satisfy current recommendations for minimal partial shear connection degree in composite floor structures with profiled steel sheeting. Detail examination of X-HVB 110 shear connectors positioned in envisaged openings of prefabricated composite slabs is performed. The experiment aims at understanding the effects of the spacing between shear connectors, orientation of shear connectors relative to the shear force direction and installation power level used for installation of cartridge fired pins, when they are used for prefabricated composite construction. In order to generate all structural performance data, this investigation included experimental investigation of cartridge fired pins performed through shear and tension tests. Extensive finite element analysis is conducted in this research in order to develop and c, Савремени трендови у грађевинарству се најчешће огледају у повећаним захтевима за убрзаном градњом, што је утицало на развој нових вртса префабрикованих бетонских плоча и средстава за спрезање. Спрезање префабрикованих бетонских плоча и челичних гредних носача најчешће се постиже постављањем можданика у отворе у бетонској плочи, који су за то предвиђени у процесу префабрикације. Предмет научног истраживања је понашање смичућих спојева остварених помоћу X-HVB можданика у префабрикованим бетонским плочама. X-HVB 110 можданици повезани су са челичним профилима уз помоћ два X-ENP-21 HVB механичка спојна средства (ексера) експлозивним упуцавањем. Приказано испитивање треба да допринесе бољем разумевању понашања X-HVB можданика у смичућим спојевима, које је тренутно засновано на испитивањима у пуним и спрегнутим бетонским плочама на профилисаним лимовима. Такође, испитивање треба да допринесе проширењу тренутно мале базе експерименталних испитивања, којa су највећим делом садржанa у техничким извештајима који нису лако доступни истраживачима. Упоредна анализа носивости заварених можданика са главом и X-HVB можданика у спрегнутим плочама са профилисаним лимом, презентована у овом раду, нагласила је потребу за додатним испитивањима ове врсте можданика када су они груписани на растојањима која су мања од минимално препоручених, како би се задовољиле тренутне препоруке у погледу минималног процента парцијалног смичућег споја. Детаљно експериментално испитивање X-HVB 110 можданика постављених у отворе префабрикованих бетонских плоча спорведно је у овом раду. Испитивање је обухватило утицај положаја и међусобног растојања можданика у односу на правац смичуће силе као и различите јачине уградње ексера. У циљу јасног сагледавања понашања ове врсте можданика, експеримeнтално испитивање ескера је спроведено кроз тестове смицања и затезања. Нумерички модели базирани на методи коначних елемената развијени су за потребе симулирања смичућих спојева са X-HVB 110 можданицима као и ескера

Different types of shear connectors, which are used for achievement of steel-concrete composite action, have been developed during decades. Their suitability for various range of structures and loadings is determined by shear resistance, ductility of shear connectors, obtained failure mechanisms and fatigue resistance. Headed studs are widely used for composite construction of buildings and bridges. Perforated shear connectors, mechanically fastened shear connectors or bolted shear connectors with mechanical couplers are alternative solution for achievement of composite action between steel and concrete. Results of experimental and numerical analysis of these types of shear connectors are used for comparative analysis and presented in this paper. Presented analysis included comparison of stiffness and different failure mechanisms for these types of shear connections, with focus on the ductility at different load levels. Besides, results are compared with recommendation given in EN 1994-1-1 for ductile shear connectors.

This paper presents the experimental programme of an extensive research project that deals with analysing the behaviour of compressed stainless steel columns with equal angle sections. The research focuses on different material and geometrical parameters of pin-ended angle columns produced from austenitic and lean-duplex stainless steel alloys. To assess the influences of initial imperfections on column compressive resistance caused by different manufacturing procedures, three types of angle products are included: cold-formed, hot-rolled and laser-welded sections. In order to obtain both elastic and inelastic ultimate responses, including flexural and torsional-flexural buckling modes, the lengths and cross-section geometries of specimens are selected to cover non-slender sections and slender sections covering the entire wide slenderness range. The experimental programme covers all relevant tests: 15 tensile coupon tests, 15 stub-column tests, 48 overall buckling tests on slender columns and 2 residual stress tests, including measurements of initial geometric imperfections. The purpose of these experiments is to provide a reliable database to determine design rules for angle members and extend the scope of procedures currently codified in EN 1993-1-4 (2015), not only to conventional angle profiles, but also to contemporary products such as laser-welded angles.

One of the most important acceptance issues regarding the implementation of small-scale wind turbines in urban environments is related to human comfort. Turbine-induced vibrations can have a large influence on small-scale turbine implementation for urban wind harvesting. A typical five-storey steel-framed office building with a roof-mounted, horizontal-axis wind turbine was numerically analysed. The aim of the work was to investigate the increase in vibration after the installation of the turbine. A comparison was made between floor vibrations caused by wind action on the building only and by wind action on the building and turbine combined. The results were then compared with requirements given in various design codes. The main outcome of the analysis is that the installation of the turbine did not compromise the building's serviceability.

Thin-walled cylindrical and conical shells represent one of the most complex structural elements considering their behaviour and susceptibility to buckling. A brief theoretical review including the presentation of different currently available design recommendations is given in this paper. Influence of initial imperfections on nonlinear behaviour of cylindrical and conical shells is also presented through numerical analysis. Shells with different wall thicknesses and different values of initial imperfections, but constant length and diameter of shell are analysed. Numerical analysis includes materially and geometrically nonlinear analysis of cylindrical and conical shells, using experimentally obtained stress-strain relation of carbon steel and stainless steel. Material nonlinearity and initial geometrical imperfections resulted in significantly lower buckling resistance of shells., Tanke kružne cilindrične i konusne ljuske predstavljaju jedan od složenijih konstruktivnih elemenata u pogledu ponašanja i osetljivosti na izbočavanje. U radu je dat kratak teorijski osvrt, s prikazom različitih, trenutno dostupnih, proračunskih preporuka. Prikazana je numerička analiza uticaja početnih imperfekcija na nelinearno ponašanje kružnih cilindričnih i konusnih ljuski. Analizirane su ljuske različite debljine zida, s konstantnim vrednostima dužine i prečnika ljuske, kao i s različitim vrednostima početnih imperfekcija. Analiza obuhvata uticaj materijalne i geometrijske nelinearnosti na ponašanje ljuski od ugljeničnog i nerđajućeg čelika, uključujući eksperimentalne krive napon-dilatacija. U radu je pokazano da materijalna nelineranost i početna geometrijska imperfekcija dovode do značajnog pada nosivosti na izbočavanje ljuski.

Savremeni trendovi u građevinarstvu u oblasti spregnutih konstrukcija od čelika i betona najčešće se ogledaju u povećanim zahtevima za ubrzanom gradnjom, razvojem novih vrsta sredstava za sprezanje i prefabrikovanom gradnjom. Mehanički spojena sredstva za sprezanje predstavljaju alternativu tradicionalno korištenim zavarenim moždanicima sa glavom. Veza ovakvih sredstava za sprezanje sa čeličnim nosačima ostvaruje se pomoću različitih mehaničkih spojnih sredstava koji se ugrađuju procesom eksplozivnog upucavanja. U literaturi se ova mehanička spojna sredstva najčešće označavaju kao ekseri sa eksplozivnim upucavanjem. Mehanički spojena sredstva za sprezanje čine jedinstven sistem formiran od samog sredstva za sprezanje, odnosno moždanika i mehaničkog spojnog sredstva, odnosno eksera. Stoga je njihovo ponašanje u spregnutim konstrukcijama u direktnoj vezi sa ponašanjem eksera sa eksplozivnim upucavanjem. Za razliku od zavarenih moždanika sa glavom ili zavrtenjeva kao sredstava za sprezanje koji se često koriste u zgradarstvu, ponašanje mehanički spojenih sredstava za sprezanje u literaturi nije još uvek detaljno objašnjeno. U ovom radu dat je prikaz X-HVB moždanika kao najpoznatijeg predstavnika mehanički spojenih sredstava za sprezanje. Objašnjeno je njihovo ponašanje u spregnutim konstrukcijama i prikazane su osnovne karakteristike eksera sa eksplozivnim upucavanjem.

Existing design codes for steel-concrete composite structures give only general information about the shear connection provided by headed studs in group arrangement. Grouting of the openings in prefabricated concrete slabs, where the grouped headed studs are placed in the deck pockets is alternative to cast-in-place decks to accomplish fast execution of composite structures. This paper considers the possibility to reduce the distance between the studs within the group, bellow the Eurocode limitations. This may lead to increased competitiveness of the prefabricated construction because more studs are placed in the group if negative effectives of smaller distances between studs are limited. The main purpose of this work is to investigate these limits and propose an analytical calculation model for prediction of the shear resistance of grouped stud arrangements in the deck pockets. An advanced FEA model, validated by results of push-out experiments, is used to analyze the shear behavior of the grouped stud with smaller distance between them than recommended by EN 1994-1. Calculation model for shear resistance, which is consistent with the existing Eurocode rules, is proposed based on a newly introduced equivalent diameter of the stud group, d(G). The new calculation model is validated by comparison to the results of FE parametric study. The distance between the studs in the longitudinal direction and the number of stud rows and columns in the group are considered as the main variables.

The Railway road bridge in Novi Sad is situated on the international railroad Belgrade-Budapest. The bridge is designed for two railway tracks (with design speed of 160 km/h), two road lanes and two footpaths. The bridge structure consists of four structures: two approach composite bridges at the banks and two steel tied network arch bridges over the river and transition structure between two arches. The spans are 27.0+177.0+ 3.0+219.0+48.0 m, totally 474.0 m in length. The rises of arches are 34.0 m and 42.0 m respectively. The width of the bridge is 31.440 m. The arches and ties, as well as the girders of the approach spans, are steel box girders. The decks of all bridge structures are the composite reinforced concrete slabs with thickness of 300 mm, locally 400 mm. The launching was very complex, in both analysis and construction. The arch bridges were fully assembled on the banks and launched by skids over the bank and by pontoons over the river, to the final position on piers. The bridge was designed fully according to European standards and additionally - according to requirements of German codes DIN-Fachbericht 101 to 104 Edition 2009 and Deutsche Bahn Richtlinie 804, Edition 2003. The bridge is, despite of heavy loads and structural complexity, very rational in steel volumes and construction costs as well. The bridge is also, with the arch span of L = 219 m, the bridge with the longest span in the world in the category of tied network arch bridges with two rail tracks. The bridge is open to rail traffic at 7th April 2018.