Flat-jack method for testing masonry

Nedavni seizmički događaji koji su protresli Hrvatsku naglašavaju potrebu za obnovom značajnog broja postojećih građevina. Veliki dio njih spada među ranjive nearmirane zidane konstrukcije. Kako bi obnova i pojačanje takvih konstrukcija bili efikasni i održivi, potrebno je provesti detaljne istražne radove u procesu ocjene postojećeg stanja građevinske konstrukcije korištenjem raznih metoda. Flat-jack metoda pokazala se kao vrlo korisna polurazorna metoda ispitivanja. Ona pomoću plosnatih preša unosi naprezanje u ziđe te posljedično uzrokuje njegovu deformaciju. Mjerenjem spomenutih naprezanja i deformacije te obradom dobivenih podataka osigurava se uvid u mehanička svojstva ziđa. Kroz tri faze spitivanja mogu se odrediti vertikalno stanje naprezanja, modul elastičnosti i početna posmična čvrstoća ziđa.The recent seismic events that shook Croatia made it clear that there is a great need for the renovation of a significant number of existing buildings. A large portion of these are vulnerable buildings made of unreinforced masonry. In order to make the renovation and strengthening of such structures efficient and sustainable, detailed investigations must be conducted to assess the existing condition of the structure. Various methods are used for this purpose. The flat-jack method has been proven to be a very useful semi-destructive testing method. Flat-jacks are used to apply stress to the masonry, causing it to deform. An insight into the mechanical properties of the masonry is acquired by measuring the aforementioned stresses and deformations and processing the measured data. The vertical stress state, the modulus of elasticity, and the initial shear strength of the masonry can be determined during the three test phases