7 research outputs found
Utjecaj nekih parametara na ponaÅ”anje i graniÄnu nosivost viÅ”edijelnih kamenih stupova pri statiÄkom optereÄenju i potresu : disertacija
In this thesis, the effect of several important parameters on the behaviour and bearing capacity of multi-drum stone columns loaded by short-term static loads and earthquakes was investigated. These parameters have not been investigated to date or have been investigated only sporadically. All of the experiments were conducted on smallscale column models using modern equipment for testing and measuring. Dynamic testing of the models was performed using an established earthquake platform. The effects of the column block number and joint type were investigated, as well as several parameters for the bolts used in the column joints (material, length, bolt diameter and the diameter of the bolt hole). Static tests were conducted separately for centric compressive loads and for bending loads with longitudinal compression. During the dynamic tests, the samples were exposed to the acceleration of three different earthquake types with a successive increase in acceleration to failure. During the action of all loads, the characteristic displacements, accelerations and strains of the model were recorded. The motion of the model was recorded with a precision camera. The aim of this research was to contribute to the development of science in the subject area, which has been accomplished through the publication of five scientific papers in relevant worldwide journals. The purpose of this research is to provide conclusions regarding the investigated effects of important multi-drum stone column parameters, and the results should find practical application in the restoration/strengthening of existing multi-drum stone columns and the creation of new multi-drum stone columns. The most important conclusions of the research are listed below. Increasing the number of blocks (joints) in the multi-drum column reduces the columnās stiffness and increases its deformability. The consequence of this is a significant reduction in the columnās bearing capacity for static loads, as well as for longer duration earthquakes, which entered great energy in the construction. For impact-type earthquakes, increasing the number of blocks in a column can result in a greater bearing capacity because the column stiffness is reduced, and smaller earthquake forces are generated in the column. Soft joints (dry, joints made from stone powder and weaker mortar), compared to rigid joints and single-block column, result in a softer column with a lower bearing capacity for static loads and long lasting earthquakes with greater generated energy. However, for impact-type earthquakes, column with soft joints can have a greater bearing capacity than columns with rigid joints or single-block columns. Bolts in multi-drum stone columns significantly contribute to their bearing capacity during earthquakes. The bolt material has no major impact on the column bearing capacity during earthquakes if the column collapse is predominantly followed by bending and less by shear, i.e., if the failure is caused by the bolts pulling out and not by shear failure. The diameter of the bolt has no major effect on the column bearing capacity when it is loaded with smaller transverse forces. In that case, a thick bolt can be unfavourable for some earthquakes, as a thick bolt increases the stiffness of the column, and pull on it larger earthquake forces. In this case, the column failure is followed by the bolt pulling out but not by its failure. When the column is subjected to large shear with respect to bending, increasing the bolt diameter increases the column capacity. The bolt length does not have a greater effect on the column bearing capacity when the bolt has no adhesion with the block, i.e., when the bolt cannot withstand tensile forces. Increasing the bolt hole diameter in relation to the bolt diameter and having a bolt that cannot withstand tensile forces decreases the column bearing capacity during an earthquake. With the same maximum amplitude, the type of earthquake (duration and predominant period) has a considerable effect on all column parameters considered in this research. Therefore, in practice, it is crucial to know what type of earthquake can be expected at the considered location.U okviru teme ove doktorske disertacije, istražen je utjecaj nekoliko važnih parametara na ponaÅ”anje i nosivost viÅ”edijelnih kamenih stupova optereÄenih kratkotrajnim statiÄkim optereÄenjima i potresom, a koja do sada nisu bila istraživana ili su istraživana samo sporadiÄno. Sva istraživanja su provedena eksperimentalno na umanjenim modelima stupova, koristeÄi suvremenu opremu za ispitivanja i mjerenja. DinamiÄka ispitivanja modela su provedena pomoÄu provjerene potresne platforme. IzmeÄu ostalog, istražen je utjecaj broja blokova i tipa sljubnica u stupu, te viÅ”e parametara trnova u sljubnicama stupa (materijal, dužina i promjer trna, te promjer rupe za trn). StatiÄka ispitivanja su provedena zasebno za centriÄno tlaÄno optereÄenje i zasebno za savijanje s uzdužnom tlaÄnom silom. Kod dinamiÄkih testova, uzorci su bili izloženi ubrzanju triju razliÄitih tipova potresa, sa sukcesivnim poveÄanjem ubrzanja do njihova sloma. Pri djelovanju svih optereÄenja, praÄeni su karakteristiÄni pomaci, ubrzanja i deformacije modela, te snimano gibanje modela preciznom kamerom. Cilj istraživanja je doprinos razvoju znanosti u predmetnom podruÄju, koji je ostvaren objavom pet znanstvenih radova u relevantnim svjetskim Äasopisima. Svrha istraživanja je donoÅ”enje zakljuÄaka u pogledu istraženih utjecaja razmatranih važnih parametara viÅ”edijelnog kamenog stupa, koji bi trebali naÄi svoju primjenu u obnovi/ojaÄanju postojeÄih i izradi novih viÅ”edijelnih kamenih stupova u praksi. Najvažniji zakljuÄci istraživanja su niže navedeni. S poveÄanjem broja blokova (sljubnica) u viÅ”edijelnom stupu, smanjuje se njegova krutost i poveÄava njegova deformabilnost. Posljedica toga je znaÄajno smanjenje njegove nosivosti za statiÄka optereÄenja, kao i za potrese dužeg trajanja koji unose veliku energiju u konstrukciju. Za potrese kratkog udarnog djelovanja, poveÄanje broja blokova u stupu može rezultirati njegovom veÄom nosivosti jer se smanjenjem krutosti stupa u njemu generiraju manje potresne sile. Meke sljubnice (suha, od kamenog braÅ”na i slabijeg morta), u odnosu na krute sljubnice i stup iz jednog bloka, takoÄer rezultiraju mekÅ”im stupom i njegovom znaÄajno manjom nosivosti za statiÄka optereÄenja i potrese dugog trajanja s veÄom generiranom energijom. MeÄutim, za potrese kratkog udarnog djelovanja, stup s mekom sljubnicom može imati veÄu nosivost nego stup s krutim sljubnicama ili iz jednog bloka po visini. Trnovi u sljubnicama viÅ”edijelnog kamenog stupa znaÄajno doprinose njegovoj nosivosti pri potresu. Vrsta materijala za trn nema veÄeg utjecaja na nosivost stupa pri potresu ako je slom praÄen dominantno savijanjem i manje posmikom, tj. ukoliko dolazi do Äupanja trnova a ne do njihovog posmiÄnog popuÅ”tanja. Promjer trna nema veÄeg utjecaja na nosivost stupa za sluÄajeve kada je optereÄen manjim popreÄnim silama. U tom sluÄaju debeli trn može biti nepovoljan za neke potrese jer se njime poveÄava krutost stupa i na njega navlaÄe veÄe potresne sile, a pri tome je slom stupa praÄen izvlaÄenjem trna a ne njegovim posmiÄnim otkazivanjem. Kada je stup optereÄen velikim utjecajem posmika u odnosu na savijanje, poveÄanje promjera trna Äe rezultirati veÄom nosivosti stupa. Dužina trna nema veÄeg utjecaja na nosivost stupa u sluÄaju kada on nema prionjivost s blokom, tj. kada ne može nositi vlaÄne sile. S poveÄanjem promjera rupe za trn u odnosu na promjer trna i kada trn ne može nositi vlak, smanjuje se nosivost stupa pri potresu. Uz istu maksimalnu amplitudu, tip potresa (trajanje i predominantni period) ima vrlo veliki utjecaj na sve razmatrane parametre u ovom istraživanju. Zato je u praksi krucijalno znati kakvi se tipovi potresa mogu oÄekivati na razmatranoj lokaciji
Effect of the Drum Height on the Seismic Behaviour of a Free-Standing Multidrum Column
The results of a shake-table study on the effect of the drum height on the seismic behaviour and bearing capacity of small-scale free-standing multidrum columns are presented. Columns of equal height with one, three, and six drums through their height were considered for the case of their self-weight only and for the case with an additional weight on the top of the column. The columns were exposed to a horizontal base acceleration of three accelerograms by successively increasing the maximum acceleration to their failure. The characteristic displacements and accelerations of the column were measured. It was concluded that an increase in the number of blocks in the column can significantly increase or decrease its ultimate bearing capacity, depending on the type of the applied accelerogram. It is expected that the experimental database can be useful in the validation of nonlinear numerical models for the dynamic analysis of multidrum columns
Osnove betonskih konstrukcija : interna skripta
Ova skripta je nastala kao pomoÄ pri savladavanju gradiva iz predmeta Osnove betonskih konstrukcija na Preddiplomskom sveuÄiliÅ”nom studiju GraÄevinarstva FGAG, Split i iz predmeta Betonske Konstrukcije 1 i Betonske Konstrukcije 2 na Preddiplomskom struÄnom studiju graÄevinarstva FGAG, Split, a takoÄer pokriva i dio materije koji se predaje u okviru predmeta Betonske Konstrukcije 1 i Betonske Konstrukcije 2 na SveuÄiliÅ”nom diplomskom studiju graÄevinarstva FGAG, Split
Osnove betonskih konstrukcija : interna skripta
Ova skripta je nastala kao pomoÄ pri savladavanju gradiva iz predmeta Osnove betonskih konstrukcija na Preddiplomskom sveuÄiliÅ”nom studiju GraÄevinarstva FGAG, Split i iz predmeta Betonske Konstrukcije 1 i Betonske Konstrukcije 2 na Preddiplomskom struÄnom studiju graÄevinarstva FGAG, Split, a takoÄer pokriva i dio materije koji se predaje u okviru predmeta Betonske Konstrukcije 1 i Betonske Konstrukcije 2 na SveuÄiliÅ”nom diplomskom studiju graÄevinarstva FGAG, Split
Mw 6.4 Petrinja earthquake in Croatia: Main earthquake parameters, impact on buildings and recommendation for their structural strengthening
Razorni potres Petrinja (opÄi pojam za potrese na Banovini) od 29.12.2020. magnitude Mw 6.4 oduzeo je 7 ljudskih života i prouzroÄio katastrofalne Å”tete na podruÄju Banovine. U radu su prikazani i analizirani najvažniji parametri potresa te naglaÅ”ena njihova važnost u razumijevanju nastalih oÅ”teÄenja i ruÅ”enja graÄevina te oblikovanju optimalne konstrukcije za njihovu obnovu. Dan je doprinos u razumijevanju složenog mehanizma nastanka potresa preko analize naponsko-deformacijskog stanja u stijenskom masivu tijekom meÄudjelovanja tektonskih ploÄa. Uzroci ruÅ”enja i oÅ”teÄenja zgrada objaÅ”njeni su kombiniranim utjecajem svojstava njihove konstrukcije, tla i samog potresa. Predložena su rjeÅ”enja optimalne konstrukcije novih zgrada, kao i rjeÅ”enja konstrukcijskog ojaÄanja oÅ”teÄenih zgrada.Strong Mw 6.4 Petrinja earthquake from 29.12.2020. took 7 lives and caused catastrophic damage in the Banovina area. The paper presents and analyses the most important earthquake parameters and highlights their importance in understanding the damage and demolition of buildings, as well as creating an optimal structure for their reconstruction. A contribution is made to the understanding of the complex mechanism of earthquake formation through the analysis of the stress-strain state in a rock mass during tectonic plate conflict. The causes of demolition and damage to buildings are explained by the combination of the properties of their structure, soil and the earthquake itself. Solutions for optimal structure of new buildings, as well as solutions for structural renovation of damaged buildings are proposed and described
Osnove betonskih konstrukcija : usklaÄeno s: HRN EN 1992-1-1:2013/A1:2015
Knjiga je prvenstveno namijenjena studentima i kao takva u potpunosti obuhvaÄa gradivo iz predmeta Osnove betonskih konstrukcija na Preddiplomskom sveuÄiliÅ”nom studiju graÄevinarstva te iz predmeta Betonske Konstrukcije 1 i Betonske Konstrukcije 2 na Preddiplomskom struÄnom studiju graÄevinarstva FGAG Split. DjelomiÄno se odnosi i na gradivo u okviru predmeta Betonske Konstrukcije 1 i Betonske Konstrukcije 2 na SveuÄiliÅ”nom diplomskom studiju graÄevinarstva te gradivo predmeta Nosive konstrukcije 1 na SveuÄiliÅ”nom preddiplomskom studiju arhitekture i urbanizma FGAG Split. Intencija je autora da se materija ne prikazuje na detaljistiÄki i u Å”irinu, veÄ da se na jasan i koncizan naÄin predstave osnove proraÄuna, dimenzioniranja i oblikovanja armirano betonskih konstrukcija. Kako je nastajala u dužem razdoblju, materijali su pratili i razvoj normi za proraÄun betonskih konstrukcija, od PBAB-a, preko europske prednorme, do najnovije europske norme za beton: HRN EN 1992-1-1:2013/A1:2015 (EC-2). Navedena norma, važeÄa u Republici Hrvatskoj te po kojoj je ovo izdanje knjige usklaÄeno, danas u svijetu nesumnjivo predstavlja jednu od najmodernijih normi za proraÄun, dimenzioniranje i oblikovanje armirano betonskih konstrukcija