Procedures for Reliability Assessment of Existing Bridges

Budući da su mnogi mostovi u svijetu davno izgrađeni, a iz društvenih i ekonomskih razloga potrebno ih je i dalje upotrebljavati, nužno je provesti ocjenjivanje njihove pouzdanosti. U radu su opisana najnovija istraživanja u svezi s tom danas vrlo aktualnom problematikom. Predložene napredne proračunske metode za ocjenjivanje postojećih mostova u više koraka utemeljene su na probabilističkoj teoriji pouzdanosti, a razmatraju se karakteristična ispitivanja materijala, ocjene stanja i zalihe nosivosti konstrukcijskog sustava i stvarna prometna opterećenja. Dan je pregled inozemnih normi i napravljena njihova usporedba.Many bridges in the world have been built a long time ago and, because of social and economic needs for their continued use, it is necessary to assess their reliability. An overview of recent studies of these now highly topical issues is presented in the paper. Proposed advanced multi-level methods for assessment of existing bridges are based on the probabilistic theory of reliability, and involve typical material testing, assessment of condition and redundancy of structural systems, and study of actual traffic load. A review of foreign codes with their comparison is presented

Seismic risk for Croatia: overview of research activities and present assessments with guidelines for the future

Iz pozicije glavnog izvršitelja za procjene rizika od potresa za Hrvatsku, napravljen je pregled brojnih i metodološki različitih procjena rizika, uključujući nepovezane pojedinačne inicijative. Cilj rada je pozicionirati i osvrnuti se na doprinose svake od procjena, ali i upozoriti na manjkavosti odnosno ograničenja. Opisana je i uobičajena metodologija analizirajući svaki od faktora seizmičkog rizika, dajući pregled sadašnjeg stanja istraživanja u Hrvatskoj i u svijetu te nudeći smjernice za daljnje strateško djelovanje jer svi postojeći rezultati ističu potres kao neprihvatljiv rizik za Hrvatsku.An overview of numerous methodologically different risk assessments, including sporadic individual initiatives, is presented from the perspective of a leading expert for earthquake risk assessments for Croatia. The aim of the paper is to evaluate and discuss contributions of each of the assessments, but also to caution about their deficiencies i.e. limitations. A common methodology for estimating seismic risk is described by analysing each of its factors, by providing an overview of current research in Croatia and worldwide, and by offering guidelines for further strategic actions, as all existing results reveal that earthquake is an unacceptable risk for Croatia

On the design of walls with openings

U radu se opisuje postupak proračuna zidova s otvorima koji je Veselin Simović uveo početkom sedamdesetih godina prošloga stoljeća. Rješenje je izvedeno u zatvorenom obliku prevođenjem sustava jednadžbi metode sila u linearnu diferencijsku jednadžbu s konstantnim koeficijentima. Spomenuti je postupak proračuna zidova s otvorima uspoređen s „modernijim“ postupkom proračuna metodom pomakâ, provedivim samo primjenom računala. Usporedbe rezultata pokazuju ograničenja primjenjivosti postupka, odnosno, vrste zidova za koje se rezultati mogu smatrati pouzdanima

Post-earthquake damage assessment of buildings – procedure for conducting building inspections

Procjene oštećenja i uporabljivosti građevina u Hrvatskoj, iskočile su u prvi plan nakon potresa u Zagrebu 22. ožujka 2020. S obzirom na manjkavosti pripremne faze, pri čemu nije provedena edukacija stručnjaka prije potresa, nego u hodu, procjene su sadržavale dozu subjektivnosti i interpretacije na temelju znanja, iskustva, ali i intuicije pojedinaca. U radu je detaljno prikazana metodologija koja može pomoći u brzim procjenama te kod detaljnih inženjerskih pregleda koji se moraju napraviti prije obnove. Prikazana metodologija se može iskoristiti u slučaju novoga razornog potresa koji se može dogoditi već sutra.Assessments of building damage and usability were of primary importance after the Zagreb earthquake of 22 March 2020. Due to deficiencies of preparatory phase, where education of experts was not carried out before the earthquake, but later on, the assessments contained certain subjectivity and interpretations, based on knowledge and experience, but also on intuition of individuals. Detailed methodology, which should improve rapid assessments and detailed engineering inspections to be performed before reconstruction, is highlighted in the paper. This methodology may be utilized if another devastating earthquake occurs, which could happen already tomorrow

Zagreb earthquake of 22 March 2020 – preliminary report on seismologic aspects and damage to buildings

U radu su opisane bitne značajke i glavne posljedice potresa magnitude 5,5 koji je u jeku pandemije virusa COVID-19 zadesio Zagreb i okolicu. Premda je potres, seizmološki gledano, bio umjerene magnitude, prouzročio je gubitak jednoga života i veliku materijalnu štetu. Napravljen je pregled stanja prije trešnje te prikaz lokacije, seizmičke aktivnosti i organizacije pregleda zgrada. Grubo su razvrstani podaci o oštećenjima, s težištem na povijesnoj jezgri i četvrtima blizu epicentra. Na kraju su istaknute nužne aktivnosti koje je odavno trebalo provesti, s nadom da će ih ovaj potres potaknuti.Significant characteristics and main consequences of the 5.5 magnitude earthquake that struck Zagreb and its surroundings in the midst of the COVID-19 pandemic are presented in the paper. Although, from the seismologic aspect, the earthquake was of moderate magnitude, it caused the loss of one life and considerable material damage. An overview of the situation before the quake is given, and information about the location, seismic activity, and organisation of building inspection activity, is presented. The data on damage are roughly classified, with the focus on historic core of the city and districts situated close to the epicentre. A strong emphasis is placed on indispensable activities that should have been carried out a long time ago, in the hope that they will be prompted by this earthquake

The analysis of a child's drawing and symbols in children's visual art

Crtež je oblik vizualne umjetnosti, a djeca svoje likovno izražavanje započinju upravo stvaranjem crteža. Pri crtanju se koriste crtačke tehnike, a tehnike koje djeca rane i predškolske dobi najčešće koriste jesu olovka i olovke u boji, ugljen, tuš i pero, flomasteri u boji te kreda u boji. Svaka crtačka tehnika ima određene specifičnosti i svojstva. Djeca od najranije dobi uživaju u likovnim aktivnostima, što je veoma bitno jer crtanje ima veliku važnost u cjelokupnom dječjem razvoju. Dječji likovni izraz mijenja se kroz nekoliko faza likovnog izražavanja, a to su faza izražavanja primarnim simbolima, faza izražavanja složenim simbolima, faza intelektualnog realizma te faza vizualnog realizma. Svaka od tih faza obuhvaća napredak likovnog izraza, spoznajni, emocionalni te grafomotorički napredak. Dječji likovni uradci skrivaju u sebi mnoga značenja i simbole koji se mogu uvidjeti likovnom analizom. Analiza likovnoga djela provodi se rastavljanjem likovnog uratka na sastavne dijelove, a postupak analize likovnog djela, bilo ono umjetničko djelo ili dječji likovni uradak, zasniva se na točno određenim kriterijima. Kod analize dječjeg crteža važno je obratiti pažnju na detalje, boje, atmosferu crteža te na raspored elemenata na papiru, što se može uvidjeti u prikazanim analizama likovnih uradaka djece predškolske dobi. Dječji likovni radovi prepuni su simbola. Potrebno je naglasiti kako pojava simbola u dječjim crtežima ne znači siromašan likovni izraz ili nemaštovitost. Dječji crtež važan je kao sredstvo pomoću kojega dijete komunicira s okolinom, a upravo simboli koje djeca crtaju nose određene poruke. U početku djeca koriste jednostavne simbole, poput kruga i crte, no simboli s vremenom postaju sve složeniji. Neki simboli koje susrećemo u dječjim likovnim uradcima su srce, kuća, drvo, cvijet s pet latica i sunce. Izrazito je bitno u svakom trenutku poticati djetetovo likovno izražavanje i poštivati djetetov način likovnog izražavanja.Drawing is a type of visual art and children start their artistic expression by creating drawings. Drawing techniques are used, and the techniques used by children at the early age and middle childhood age are pencil and coloured pencil, charcoal, pen and ink, felt-tip pen and coloured chalk. Each drawing technique has its specificities and characteristics. Children enjoy artistic activities from a very early age, which is very important since drawing has great significance in the overall child development. A child’s artistic expression changes in several stages. These are the scribbling stage, the symbols stage, the intellectual realism stage, and the visual realism stage. Each stage covers the artistic expression development, cognitive, emotional and graphomotor development. Meanings and symbols are hidden in children’s works of art and can be distinguished by conducting art analysis. In art analysis, the work of art is disassembled into its components and the analysis procedure is based on precisely defined criteria. When analysing a child’s drawing, it is important to pay attention to details, colours, the atmosphere, and the way the elements are placed on paper, which can be seen in the analysis of pre-school children’s drawings. Children’s works of arts are full of symbols. It is necessary to point out that the symbols in children’s works of art do not mean their artistic impression is poor or they lack imagination. A child’s drawing is important as a means of communication used by the child to communicate with the environment, and the drawn symbols bear certain messages. Simple symbols are used in the beginning, such as a circle and a line, but eventually, they become more complex. Some symbols found in children’s works of art are a heart, a house, a tree, a flower with five petals and the sun. It is extremely important to encourage a child’s artistic expression all the time and respect the way a child does that

The analysis of a child's drawing and symbols in children's visual art

Crtež je oblik vizualne umjetnosti, a djeca svoje likovno izražavanje započinju upravo stvaranjem crteža. Pri crtanju se koriste crtačke tehnike, a tehnike koje djeca rane i predškolske dobi najčešće koriste jesu olovka i olovke u boji, ugljen, tuš i pero, flomasteri u boji te kreda u boji. Svaka crtačka tehnika ima određene specifičnosti i svojstva. Djeca od najranije dobi uživaju u likovnim aktivnostima, što je veoma bitno jer crtanje ima veliku važnost u cjelokupnom dječjem razvoju. Dječji likovni izraz mijenja se kroz nekoliko faza likovnog izražavanja, a to su faza izražavanja primarnim simbolima, faza izražavanja složenim simbolima, faza intelektualnog realizma te faza vizualnog realizma. Svaka od tih faza obuhvaća napredak likovnog izraza, spoznajni, emocionalni te grafomotorički napredak. Dječji likovni uradci skrivaju u sebi mnoga značenja i simbole koji se mogu uvidjeti likovnom analizom. Analiza likovnoga djela provodi se rastavljanjem likovnog uratka na sastavne dijelove, a postupak analize likovnog djela, bilo ono umjetničko djelo ili dječji likovni uradak, zasniva se na točno određenim kriterijima. Kod analize dječjeg crteža važno je obratiti pažnju na detalje, boje, atmosferu crteža te na raspored elemenata na papiru, što se može uvidjeti u prikazanim analizama likovnih uradaka djece predškolske dobi. Dječji likovni radovi prepuni su simbola. Potrebno je naglasiti kako pojava simbola u dječjim crtežima ne znači siromašan likovni izraz ili nemaštovitost. Dječji crtež važan je kao sredstvo pomoću kojega dijete komunicira s okolinom, a upravo simboli koje djeca crtaju nose određene poruke. U početku djeca koriste jednostavne simbole, poput kruga i crte, no simboli s vremenom postaju sve složeniji. Neki simboli koje susrećemo u dječjim likovnim uradcima su srce, kuća, drvo, cvijet s pet latica i sunce. Izrazito je bitno u svakom trenutku poticati djetetovo likovno izražavanje i poštivati djetetov način likovnog izražavanja.Drawing is a type of visual art and children start their artistic expression by creating drawings. Drawing techniques are used, and the techniques used by children at the early age and middle childhood age are pencil and coloured pencil, charcoal, pen and ink, felt-tip pen and coloured chalk. Each drawing technique has its specificities and characteristics. Children enjoy artistic activities from a very early age, which is very important since drawing has great significance in the overall child development. A child’s artistic expression changes in several stages. These are the scribbling stage, the symbols stage, the intellectual realism stage, and the visual realism stage. Each stage covers the artistic expression development, cognitive, emotional and graphomotor development. Meanings and symbols are hidden in children’s works of art and can be distinguished by conducting art analysis. In art analysis, the work of art is disassembled into its components and the analysis procedure is based on precisely defined criteria. When analysing a child’s drawing, it is important to pay attention to details, colours, the atmosphere, and the way the elements are placed on paper, which can be seen in the analysis of pre-school children’s drawings. Children’s works of arts are full of symbols. It is necessary to point out that the symbols in children’s works of art do not mean their artistic impression is poor or they lack imagination. A child’s drawing is important as a means of communication used by the child to communicate with the environment, and the drawn symbols bear certain messages. Simple symbols are used in the beginning, such as a circle and a line, but eventually, they become more complex. Some symbols found in children’s works of art are a heart, a house, a tree, a flower with five petals and the sun. It is extremely important to encourage a child’s artistic expression all the time and respect the way a child does that

The analysis of a child's drawing and symbols in children's visual art

Crtež je oblik vizualne umjetnosti, a djeca svoje likovno izražavanje započinju upravo stvaranjem crteža. Pri crtanju se koriste crtačke tehnike, a tehnike koje djeca rane i predškolske dobi najčešće koriste jesu olovka i olovke u boji, ugljen, tuš i pero, flomasteri u boji te kreda u boji. Svaka crtačka tehnika ima određene specifičnosti i svojstva. Djeca od najranije dobi uživaju u likovnim aktivnostima, što je veoma bitno jer crtanje ima veliku važnost u cjelokupnom dječjem razvoju. Dječji likovni izraz mijenja se kroz nekoliko faza likovnog izražavanja, a to su faza izražavanja primarnim simbolima, faza izražavanja složenim simbolima, faza intelektualnog realizma te faza vizualnog realizma. Svaka od tih faza obuhvaća napredak likovnog izraza, spoznajni, emocionalni te grafomotorički napredak. Dječji likovni uradci skrivaju u sebi mnoga značenja i simbole koji se mogu uvidjeti likovnom analizom. Analiza likovnoga djela provodi se rastavljanjem likovnog uratka na sastavne dijelove, a postupak analize likovnog djela, bilo ono umjetničko djelo ili dječji likovni uradak, zasniva se na točno određenim kriterijima. Kod analize dječjeg crteža važno je obratiti pažnju na detalje, boje, atmosferu crteža te na raspored elemenata na papiru, što se može uvidjeti u prikazanim analizama likovnih uradaka djece predškolske dobi. Dječji likovni radovi prepuni su simbola. Potrebno je naglasiti kako pojava simbola u dječjim crtežima ne znači siromašan likovni izraz ili nemaštovitost. Dječji crtež važan je kao sredstvo pomoću kojega dijete komunicira s okolinom, a upravo simboli koje djeca crtaju nose određene poruke. U početku djeca koriste jednostavne simbole, poput kruga i crte, no simboli s vremenom postaju sve složeniji. Neki simboli koje susrećemo u dječjim likovnim uradcima su srce, kuća, drvo, cvijet s pet latica i sunce. Izrazito je bitno u svakom trenutku poticati djetetovo likovno izražavanje i poštivati djetetov način likovnog izražavanja.Drawing is a type of visual art and children start their artistic expression by creating drawings. Drawing techniques are used, and the techniques used by children at the early age and middle childhood age are pencil and coloured pencil, charcoal, pen and ink, felt-tip pen and coloured chalk. Each drawing technique has its specificities and characteristics. Children enjoy artistic activities from a very early age, which is very important since drawing has great significance in the overall child development. A child’s artistic expression changes in several stages. These are the scribbling stage, the symbols stage, the intellectual realism stage, and the visual realism stage. Each stage covers the artistic expression development, cognitive, emotional and graphomotor development. Meanings and symbols are hidden in children’s works of art and can be distinguished by conducting art analysis. In art analysis, the work of art is disassembled into its components and the analysis procedure is based on precisely defined criteria. When analysing a child’s drawing, it is important to pay attention to details, colours, the atmosphere, and the way the elements are placed on paper, which can be seen in the analysis of pre-school children’s drawings. Children’s works of arts are full of symbols. It is necessary to point out that the symbols in children’s works of art do not mean their artistic impression is poor or they lack imagination. A child’s drawing is important as a means of communication used by the child to communicate with the environment, and the drawn symbols bear certain messages. Simple symbols are used in the beginning, such as a circle and a line, but eventually, they become more complex. Some symbols found in children’s works of art are a heart, a house, a tree, a flower with five petals and the sun. It is extremely important to encourage a child’s artistic expression all the time and respect the way a child does that

Influence of contact stresses on bearing capacity of traditional stone columns

Tradicijski kameni stupovi, izvedeni spajanjem baze, tijela i kapitela trnom u osi stupa, često su prožeti karakterističnim pukotinama u blizini spojeva koje kontinuirano propagiraju. Brojnim sanacijama tijekom povijesti ne uspijeva se zaustaviti raspucavanje, što upućuje na neku suštinsku manjkavost. Radi utvrđivanja uzroka problema pokrenuto je sustavno istraživanje koje se temelji na nizu numeričkih modela različitih složenosti i laboratorijskom ispitivanju na gotovo realnim dimenzijama uzoraka. U ovom radu je prikazan dio rezultata koji opisuje karakteristično ponašanje stupova.Traditional stone columns, built by linking the base, body of column and capital with a dowel in the column axis, are often characterized by typical cracks in connection zones that are continuously propagating. Despite numerous retrofit, this cracking can not be stopped, which points to an intrinsic defect. A systematic study involving a number of numerical models of variable complexity, and laboratory testing of quasi-real size samples, was initiated In order to determine the cause of the problem. Some results describing typical behaviour of columns are presented in the paper

Influence of spatial variability of ground motion on seismic response of bridges

An approach to seismic analysis of bridges under spatially variable ground motions is presented. The phenomenon of spatial variability of earthquakes, its effects on bridge response, and differences with respect to simultaneous excitation of supports, are explained. The model of such excitation is described in detail, and procedures for generation of spatially variable ground motions are outlined. Numerical analysis methods, efficient for solving this problem, are also presented. The described methodology is applied in the seismic analysis of an arch bridge. The analysis results show that the spatial variability of ground motions has a detrimental effect on most of the analysed bridge response values