Analysis of castellated beams according to Eurocode 3

Razmatrani su saćasti nosači kao alternativa punostijenim nosačima na velikim rasponima. Opisana su novija istraživanja i mogući načini otkazivanja takvih konstrukcijskih elemenata. U radu je prikazan proračun takvih nosača prema normi Eurokod 3, a dobiveni rezultati uspoređuju se s normom DIN koja se rabila u nas. Na temelju provedenih parametarskih analiza upozoreno je na područje ekonomične primjene saćastih nosača s obzirom na njihove relativne vitkosti i veličine otvora.The use of castellated beams instead of solid web beams for large spans is considered. Some recent studies are presented, and conditions under which such structural elements can prove defective are proposed. The analysis of such beams according to Eurocode 3 is presented in the paper, and the results obtained are compared with the DIN standard, which is used in our country. Taking note of appropriate parametric analyses, the authors point to the area in which castellated beams can be economical, because of their relative slenderness and span sizes

Reliability of castellated beams subjected to lateral-torsional buckling

Linija izvijanja za određivanje otpornosti saćastih nosača na bočno-torzijsko izvijanje u Eurokodu 3 nije jednoznačno određena. Prikazani su rezultati vlastitih laboratorijskih ispitivanja na temelju kojih je na probabilističkoj razini istražena veličina indeksa pouzdanosti ß u odnosu na ciljanu vrijednost za klasu konstrukcija RC2 primjenom sve četiri linije izvijanja. Utvrđene su linije izvijanja (b i c) prikladne za određivanje bočno-torzijske otpornosti saćastih nosača.The buckling curve that defines resistance of castellated beams to lateral-torsional buckling has not been unambiguously defined in Eurocode 3. The authors present laboratory results on the basis of which the reliability index ß was defined on the probabilistic level in relation to target value for structural category RC2, using all four of buckling curves. The buckling curves (b and c) have been determined as appropriate for defining lateral-torsional resistance of castellated beams

Conservation Guidelines for Monumental Buildings from the Aspect of Safety - on the Example of the Restoration of Dubrovnik

Nakon oštećenja nastalih u Domovinskom ratu bilo je potrebno obnoviti monumentalne zgrade u Dubrovniku. Obnovu je trebalo započeti hitno radi sprečavanja daljnjeg propadanja onoga što je ostalo. Pritom se postavlja pitanje koliko poštovati konzervatorske smjernice i na koji ih način uklopiti u sigurnosne zahtjeve. U budućnosti bi trebalo izraditi preporuke koje bi pomirile te zahtjeve.After war damage it was necessary to renew historical buildings. Renewal had to be quick to prevent the further deterioration of what was left. The problem appeared of how to honour conservation guidelines while complying with safety demands. In future recommendations should be made to reconcile these requirements

Analysis of Vehicle Vibrations – New Approach to Rating Pavement Condition of Urban Roads

Urban road infrastructure is daily burdened by heavy traffic volume. Pavement structure roughness observations are significantly more difficult in urban agglomerations than on roads in unpopulated areas. Roughness, expressed by IRI (International Roughness Index), directly affects the quality and safety of road traffic. Within the framework of the pavement management in relation to safety and the achievement of the best possible ride comfort, it is very important to foresee when a road should be reconstructed. The method for quality evaluations of safety and ride comfort on urban roads presented in this paper is based on vehicle vibrations measurements. In the article, measuring of vehicle vibrations was performed on the main urban roads in Zagreb (Croatia). Measurements covered roads with different pavement surface roughness. This method can be simply and very easily used in pavement management aimed at achieving road safety and better ride comfort. The results of measurements according to this method could be used by traffic and civil engineering experts as an indication for the roads that require reconstruction or maintenance. KEY WORDS: urban roads, traffic flow, safety, vehicle vibrations, road surface roughness (IRI

Safety of roadside columns in case of vehicle impact

U radu je dan cjeloviti pregled pasivno pouzdanih stupova uz prometnice s obzirom na materijal izrade i svojstva apsorpcije energije. Razmatrane su razine pasivne pouzdanosti stupova za putnike u vozilu. Analizirano je ponašanje triju tipova stupova pri sudaru s vozilom, i to s obzirom na mogućnost apsorbiranja određene količine energije, način otkazivanja nosivosti i sigurnost putnika u vozilu. Detaljno su prikazane prednosti i nedostaci primjene pasivno pouzdanih stupova u odnosu na tradicionalne krute stupove, koji se danas još uvijek u najvećoj mjeri ugrađuju uz prometnice.A comprehensive overview of passively safe roadside columns, with an emphasis on materials they are made of and energy absorption properties, is presented in the paper. Levels of passive safety of columns with respect to safety of vehicle occupants are considered. The behaviour of passively safe roadside columns in impact with vehicles is analyzed with respect to their energy absorption possibilities, failure modes and safety of vehicle occupants. Advantages and deficiencies of the use of passively safe columns, as compared to traditional rigid columns that are today most often used alongside roadways, are presented in full detail