Behaviour of shear connections realised by connectors fastened with cartridge fired pins

Composite action between steel beams and prefabricated or solid concrete slabs can be achieved with various types of shear connectors which differ considering their main properties, installation time and required equipment at the construction site. Mechanically fastened shear connectors represent an alternative solution to the traditionally used welded headed studs or bolted shear connectors. X-HVB shear connectors fastened with two X-ENP-21 HVB cartridge fired pins are their main representative. The behaviour of shear connection realised by X-HVB shear connectors is investigated through experiments and numerical analysis of both parts: shear connectors and cartridge fired pins. Main achievements of this investigation are presented in this paper and should lead to a better understanding of X-HVB shear connectors behaviour and extension of the currently small basis of available experimental results

Ponašanje smičućih spojeva izvedenih moždanicima sa ekserima 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 calibrate FE models of push-out test specimens of X-HVB 110 shear connectors, and shear and tension tests of cartridge fired pins, based on the results of presented experimental research. The novelty in the FE modelling approach developed in this study is phenomenological simulation of installation procedure of cartridge fired pins resulting in preloading of the pins and interaction with iii the base material. Numerical FE models are developed through extensive calibration of main parameters which are introduced in FE simulation of firing the pins in tension tests and further sensitivity study. Parametric study of push-out FE models is performed for X-HVB 110 shear connectors through variation of concrete and steel base material properties. Main failure mechanisms which are obtained through experimental investigation of X-HVB 110 shear connectors in prefabricated concrete slabs are related to deformation capacity and pull-out of cartridge fired pins from the steel base material. Developed FE models of push-out test series matched the failure mechanisms obtained through experimental investigation. Pull-out of cartridge fired pins in FE models is defined by equivalent compressive contact stresses and friction at the interface between the base material and pins modelled as separate parts. This resembles the physical mechanism of the load transfer of cartridge fired pins and is a recommended modelling procedure as it gives good agreement with experimental results. Presented FE modelling approach of installation procedure of cartridge fired pins highlights the clamping of the fastener in steel base material as the most dominant anchorage mechanism. Prediction models for pull-out resistance of cartridge fired pins loaded in tension and shear resistance of X-HVB shear connectors are proposed based on the presented results of experimental and numerical investigation.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 са експлозивним упуцавањем који су оптерећени на смицање и затезање и v калибрисани су према резултатима експерименталног испитивања. Симулација уградње ексера са експлозивним упуцавањем која је дефинисана кроз нумеричке моделе резултовала је преднапрезањем ексера и дефинисањем посебних услова интеракције између ексера и основног материјала. Нумерички модели су развијени кроз опсежну калибрацију основних параметара који су кориштени за дефинисање процеса уградње и накнадно су анализирани кроз студију осетљивости спроведну на моделима са X-HVB 110 можданицима. Параметарска анализа спроведена је на моделима смичућих спојева X-HVB 110 можданика кроз промену механичких својстава бетона и основног челичног материјала. Основни модели лома који су се појавили кроз експериментално испитивање повезани су са деформацијом ексера и њиховим извлачењем из основног челичног материјала. Развијени нумерички модели смичућих спојева са X-HVB 110 можданицима потврдили су овакве видове лома. Носивост на извачење ексера из основног челичног материјала дефинисана је кроз еквивалентни напон притиска и коефицијент трења који је развијен на контактној површини између ексера и основног челичног материјала. Овакав начин нумеричког моделирања процеса уградње ескера показао је добро слагање са резултатима експерименталног испитивања и наглашава укљештење ексера у основни челични материјал као најдоминантнији механизам анкеровања. Предиктивни изрази за носивост ексера на извлачење и носивост X-HVB можданика у смичућим спојевима дефинисани су у овом раду на основу презентованог експерименталног и нумеричког испитивања

Design of pedestrian bridge according to Eurocode 9

Aluminum alloys, due to its numerous advantages, is widely used in the construction of various types of structures in civil engineering. Design of pedestrian bridge, entirely constructed of extruded elements made of aluminum alloy EN-AW 6082 T6 with cross sections designed to enable the use of innovative joints, is presented in this paper. The design and construction of special bolted joints is presented using the recommendations given in standard for design of aluminum structures CNR-DT 208/2011. Also, calculation of pedestrian bridge vibrations through different design methods is given here. Results of numerical analysis are compared with the recommendations from different currently available standards and literature referring to the comfort criteria of pedestrian bridge vibrations

Recent research on ductility of perforated shear connectors

Significant implementation of Perfobond shear connectors in construction of composite steel-concrete structures resluted in development of entirely new type of shear connectors, denoted as perforated shear connectors. Except the shear resistance of this type of shear connector, the overall behaviour of shear connection is strongly influenced by shear connector geometry. Ductility of shear connector, which is strongly influenced by connectors geometry, defines the behaviour of shear connection. The results of resent research on ductility of perforated shear connectors are obtained from numerical models which are calibrated with results of experimental investigation of this type of shear connector. The results of extensive numerical analysis were used for definition of direct relation between connectors ductility and geometry and presented in this paper

Resistance and serviceability analysis of steel footbridge structure according to Eurocode

This paper briefly presents resistance and serviceability analysis of steel footbridge structure. The main structural system consists of cold-formed members, which were designed according to EN 1993-1-3. Analysis of vibration of the footbridge structure was performed, including comparative study from the aspect of different criteria regarding the comfort according to Eurocode and SETRA/AFGC recommendations. Additionally, the paper compares behavior of steel footbridge with static and structural equivalent footbridge whose base material is aluminum alloy

Design recommendations of floor vibrations induced by human activities

Structural engineers are now facing with new demands towards long spans, lightweight floors in steelconcrete composite construction and big open interiors. Thеsе new design trends аrе leading to the extensive problems related to the serviceability limit state, especially problems with unwanted floor vibrations. Annoying vibrations caused by human activities are an important serviceability problem, which can significantly affect the comfort of people, quality of life and structures functionality. Over past years many design recommendations of floor vibrations induced by human activities have been published. This paper presents a short overview of dynamic loads modeling and design recommendations of floor vibrations induced by human activities

The influence of a roof mounted small-scale HAWT on headed studs fatigue resistance

Installation of small-scale wind turbines in urban regions can gain higher energy efficiency, considering that energy production takes place at the place of its consumption. The aim of this work is to investigate effects of installation of a small-scale horizontal axis wind turbine (HAWT) on a roof structure of an existing building. This paper is focused on fatigue resistance of headed studs that are preinstalled in the building roof composite steel-concrete deck to ensure shear connection and that are indirectly dynamically loaded during wind turbine operation. Turbulent wind profiles with mean wind speeds from 3 m/s up to 15 m/s are generated and applied on the model of HAWT with 5 m rotor diameter using Ashes software package. Time-dependent forces and bending moments induced by wind turbine operation are applied on the composite roof deck model. Based on the time-history of transverse force in the composite steel-concrete beam and wind speed records during a year, fatigue cumulative damage of headed studs is calculated according to Eurocode. It is obtained that installation of HAWT do not significantly affect residual life of headed studs with reference to fatigue

Najnovije evropske preporuke za proračun širokih veza greda-stub sa čeonom pločom

Connections made by use of wide end plates, i.e., by means of four bolts in one row are widely used in steel structures, i.e., in building engineering. On the other hand, the applicable version of European standard EN 1993-1-8, does not provide recommendations for designing of such connections but rather limits itself to application of somewhat narrow bonds). Extensive research has been conducted in recent years throughout Europe in order to extend implementation of Eurocode with regards to connections made by wide end plates. This paper will show the latest research conducted in this engineering field, as well as key calculation points relating to resistance of a rigid joint made by use of four bolts in one row.Veze sa širokom čeonom pločom, odnosno sa četiri zavrtnja u redu imaju značajnu primenu u čeličnim konstrukcijama u zgradarstvu. Međutim, trenutna verzija evropskog standarda EN 1993-1-8, ne daje preporuke za projektovanje ovakvih veza, već se ograničava samo na primenu uskih veza. Proteklih godina širom Evrope su vršena istraživanja sa ciljem da se proširi primena evrokoda i na veze sa širokim čeonim pločama. U ovom radu su prikazana najnovija istraživanja u ovoj oblasti, kao i osnovne specifičnosti proračuna nosivosti momentne veze sa četiri zavrtnja u jednom redu

Experimental investigation of X-HVB shear connectors in prefabricated composite decks

Increasing demands towards fast construction and smallest possible quantity of work resulted in development of different types of prefabricated composite decks and group arrangement of shear connectors. Short presentation of basic characteristics of X-HVB shear connectors and powder-actuated fasteners is given in this paper. Experimental investigation of X-HVB shear connectors through standard push-out tests, according to EC4:2004, is presented in this paper. Two different orientations of shear connectors, forward and backwards to the shear force are experimentally investigated

The influence of a roof mounted small-scale HAWT on headed studs fatigue resistance

Installation of small-scale wind turbines in urban regions can gain higher energy efficiency, considering that energy production takes place at the place of its consumption. The aim of this work is to investigate effects of installation of a small-scale horizontal axis wind turbine (HAWT) on a roof structure of an existing building. This paper is focused on fatigue resistance of headed studs that are preinstalled in the building roof composite steel-concrete deck to ensure shear connection and that are indirectly dynamically loaded during wind turbine operation. Turbulent wind profiles with mean wind speeds from 3 m/s up to 15 m/s are generated and applied on the model of HAWT with 5 m rotor diameter using Ashes software package. Time-dependent forces and bending moments induced by wind turbine operation are applied on the composite roof deck model. Based on the time-history of transverse force in the composite steel-concrete beam and wind speed records during a year, fatigue cumulative damage of headed studs is calculated according to Eurocode. It is obtained that installation of HAWT do not significantly affect residual life of headed studs with reference to fatigue