Use of steel in modern housing construction

Opisuju se problemi stanogradnje polazeći od toga da su troškovi građenja vrlo visoki, a i rokovi izgradnje su dugi. Upozorava se na potrebu pronalaženja inovativnih putova građenja kako bi se problemi riješili. Prikazani su i detaljno obrazloženi sustavi građenja upotrebom čeličnih konstrukcija visoke razine predgotovljenosti koji do sada nisu primjenjivani u Hrvatskoj. Navedeni su brojni inozemni primjeri stambene gradnje u čeliku koji daju argumente za primjenu u Hrvatskoj.Housing problems are described and an emphasis is placed on the fact that construction costs are very high, and that construction times are quite long. It is stressed that innovative construction methods must be found in order to solve problems currently burdening this sector. Construction systems involving steel structures with high level of prefabrication, not as yet applied in Croatia, are presented and explained in great detail. Numerous foreign examples of steel-based housing projects justifying the introduction of such construction in Croatia are presented

Use of steel in modern housing construction

Opisuju se problemi stanogradnje polazeći od toga da su troškovi građenja vrlo visoki, a i rokovi izgradnje su dugi. Upozorava se na potrebu pronalaženja inovativnih putova građenja kako bi se problemi riješili. Prikazani su i detaljno obrazloženi sustavi građenja upotrebom čeličnih konstrukcija visoke razine predgotovljenosti koji do sada nisu primjenjivani u Hrvatskoj. Navedeni su brojni inozemni primjeri stambene gradnje u čeliku koji daju argumente za primjenu u Hrvatskoj.Housing problems are described and an emphasis is placed on the fact that construction costs are very high, and that construction times are quite long. It is stressed that innovative construction methods must be found in order to solve problems currently burdening this sector. Construction systems involving steel structures with high level of prefabrication, not as yet applied in Croatia, are presented and explained in great detail. Numerous foreign examples of steel-based housing projects justifying the introduction of such construction in Croatia are presented

Girder-pier connection modeling according to Eurocode 3

Razmatra se modeliranje priključaka između nosača i stupova uvažavajući njihovo stvarno ponašanje opisano Mj-f krivuljom. Prvo su općenita razmatranja o novoj filozofiji proračuna priključaka, prema Eurokodu 3. Zatim se opisuje metoda komponenata kao analitička metoda karakterizacije priključaka. Identificirane su i obrađene komponente koje čine priključak nosača i stupa u vijčanoj izvedbi. Primjena opisanog modeliranja pokazana je posebno razvijenim kompjutorskim programom CoP.The modeling of girder/pier connections is analyzed taking into account real behavior of such connections as described by the Mj-f curve. General considerations relating to the new connection design philosophy, as based on Eurocode 3, are given in the initial part of the paper. The method of components, an analytical method for characterization of connections, is then described. Components enabling bolted connection between girders and piers are identified and analyzed. The use of the described modeling procedure is shown by means of a specially devised computer program CoP

Reliability of steel railway bridges from the aspect of fatigue

Prikazana je analiza pouzdanosti čeličnih željezničkih mostova iz aspekta umora. Istaknute su prednosti primjene probabilističkog pristupa u odnosu na deterministički pristup. Izračunane su statističke vrijednosti baznih varijabli. Posebno je razmatrana bazna varijabla oštećenja koja je poznata pod nazivom Minerov koeficijent. Formirana je jednadžba graničnog stanja. Indeks pouzdanosti proračunan je za sedam karakterističnih detalja željezničkih mostova na pruzi Zagreb – Rijeka.The analysis of reliability of steel railway bridges, focusing on their resistance to fatigue, is given Advantages of using probabilistic rather than deterministic approach are presented. Statistical values of basic variables are calculated. A special emphasis is placed on the basic variable known as the Miner\u27s coefficient. The limit state equation is formulated. The reliability index is calculated for seven typical details of railway bridges built along the Zagreb - Rijeka railway line

Selection of steel based on ductility

Činjenica da danas postoji više od 2500 vrsta čelika uvelike otežava ispravan izbor pri projektiranju. Specifični zahtjevi za izbjegavanje krtog loma definirani su u EN 1993-1-10. U radu je prikazana metoda procjene sigurnosti za izbjegavanje krtog loma preko mehanike loma, kao i teorijska pozadina inženjerskih pravila definiranih u EN 1993-1-10. Osim uobičajene primjene EN 1993-1-10, pokazane su mogućnosti njene primjene kod specifičnih zahtjeva žilavosti zbog visoke stope prirasta deformacije i/ili visokih učinaka hladne deformacije.Designers are nowadays at difficulty when selecting proper steel grade, as over 2500 types of steel are available on the market. Specific requirements for the avoidance of brittle fracture are defined in EN 1993-1-10. The method for safety assessment with regard to avoidance of brittle fracture via fracture mechanics, and theoretical background of structural rules defined in EN 1993-1-10, are presented in the paper. In addition to the normal use of EN 1993-1-10, its other uses, in case of specific ductility requirements due to high strain rate and/or high cold strain effects, are also presented

Modeling connections of steel frame structures

Prikazuje se međudjelovanje čeličnih okvira i njihovih priključaka te metoda dimenzioniranja priključaka prema EC 3. Opisana su četiri temeljna pojma vezana uz novi pristup dimenzioniranju priključaka, a to su: karakterizacija, klasifikacija, modeliranje i idealizacija. Istaknute su prednosti metode komponenata, usvojene u EC 3, u odnosu na dosadašnji postupak modeliranja priključaka. Također su obrazložene i ekonomske opravdanosti novog načina dimenzioniranja priključaka.The interaction between steel frames and their connections is explained, and the connection dimensioning method according to EC 3 is presented. Four basic terms related to novel approach to connection dimensioning are described. These terms are: characterization, classification, modeling and idealization. An emphasis is placed on advantages of component method, adopted in EC 3, when compared to the procedure currently used for connection modeling. Economic bases for the use of the new connection dimensioning method are also explained

Differences in estimating reliability of normal and exceptional structures

Prikazana je i obrazložena podjela na uobičajene i iznimne konstrukcije sa stajališta razlikovanja pouzdanosti. Zbog činjenice da kod procjene pouzdanosti iznimnih konstrukcija nema dovoljno iskustva i za njih ne vrijede važeće norme detaljnije su u razmatranju obuhvaćene neke kategorije takvih konstrukcija. Na temelju razlikovanja pouzdanosti uobičajenih i iznimnih konstrukcija, provedena je analiza tih dviju kategorija konstrukcija razmatranih na razini parcijalnih koeficijenata.The division of structures into normal and exceptional ones is presented and explained from the standpoint of their differences in reliability.As estimation of reliability of exceptional structure is hindered by insufficient experience, and by the fact that they can not be measured against applicable standards, this analysis also focuses on individual categories of such structures.Based on differentiation between reliability of normal and exceptional structures, these two categories of structures are analyzed at the level of partial factors

Application of cold formed hollow steel sections

Prema EN 1993-1-1 primjena šupljih profila dopuštena je u izradi čeličnih konstrukcija neovisno o tome jesu li profili toplo dogotovljeni prema EN 10210 ili hladno oblikovani prema EN 10219. Kod projektanata često postoji dvojba u vezi s primjenom hladno oblikovanih profila uslijed negativnog utjecaja hladnog oblikovanja na njihovo ponašanje. Nedoumicu može izazivati i nedorečenost u normi EN 1993-1-8 koja se odnosi na mogućnost zavarivanja u hladno oblikovanim zonama. Osnovna svrha rada je prikazati smjernice za odabir pravokutnih šupljih profila kod projektiranja čeličnih konstrukcija, a posebno se obrazlaže opravdanost primjene hladno oblikovanih profila.According to EN 1993-1-1, the application of hollow steel sections is permitted in the execution of steel structures, regardless of whether they are hot finished according to EN 10210 or cold finished according to EN 10219. Steel designers often have doubts about the use of cold formed hollow sections due to unfavourable effects of cold forming. Such doubts may be due to inconsistencies in EN 1993-1-8 relating to the permissibility of welding in cold formed zones. The main objective of this paper is to present guidelines for the selection of appropriate rectangular hollow sections in the design of steel structures, with justification of the use of cold formed hollow sections

A modern approach to proving fire resistance of structures

Prikazana je praksa i pristup zaštiti konstrukcija od požara u Hrvatskoj. Opisane su mjere zaštite od požara koje se predviđaju glavnim projektom. Iz toga se opisa vidi nesređenost stanja u pogledu primjene inozemnih i domaćih propisa i smjernica. Dane su temeljne postavke Eurokoda o pristupu problemu požara. Na primjeru je pokazana mogućnost dobivanja optimalnih rješenja adekvatnim proračunom. Autori preporučuju hitnu promjenu prakse vezane uz zaštitu konstrukcija od požara.Current practices and approaches to the protection of structures against fire hazard in Croatia are presented. Fire protection measures that are usually specified in detailed design documents are described. This description reveals that the current situation regarding application of foreign and national regulations and guidelines is quite disorderly. Principal Eurocode directives related to the fire protection issue are presented. An example is used to illustrate the way in which optimum analytical solutions can be found. The authors recommend urgent change of current practices regarding protection of structures against fire hazard