Precast reinforced concrete industrial buildings are one of the most common structural systems in the civil engineering practice. Nevertheless, their seismic response has been poorly investigated. Data about the response of cladding panels and their connections to the main structural system have not been available at all. Therefore the cyclic and the monotonic response of typical connections of cladding panels and the main structural system of precast buildings was investigated within the SAFECLADDING project. Three types of connections were analysed: a) typical connections of vertical panels, b) typical connections of horizontal panels and c) angles that are used for both types of panels. Thirty, mostly cyclic tests were performed. Two types of connections of vertical panels were investigated: connections, which include cold formed and hot rolled channels. Their response in the horizontal as well as vertical direction was examined. The mechanism of the response of these connections, subjected to horizontal cyclic load, had not been known at all before the experiments. Therefore, one of the main results of these investigations was the identification of the main phases of the response. The type of the failure under the horizontal load depended on the type of the channels, whether they were cold formed or hot rolled, however the strength of both types of connections was similar. In cyclic tests it was relatively small. Both, the strength as well as the sliding of the strap, were considerably larger in the monotonic tests. The response in the vertical direction was essentially sliding as long as the gap between the panel and the beam was not closed. In other investigated connections, the response was considerably different. The strength was larger, particularly in the connections of the horizontal panels and columns. The seismic capacity of typical connections of cladding panels in industrial buildings has been defined for the first time. It was found that these connections can be quite vulnerable when they are subjected to strong seismic load. This data, together with properly estimated seismic demand (see next socio-economic achievement), enable development of the methodology for estimation of the level of the seismic vulnerability of industrial buildings, identification of those buildings, where the seismic strengthening should be provided, and the identification of optimal strengthening procedures. In this way, a relatively small investment into the increased seismic safety will prevent huge direct and indirect costs due to the collapse of panels, which was clearly demonstrated during the last earthquakes in Italy.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 6517601The strength and the response mechanisms of connections of cladding panels were defined based on the experimental investigations. These data were further used to define numerical models of connections, which were employed in the analysis of the seismic demand of connections and panels, and the role of panels in the global seismic response of the whole building. This was one of the main contributions of the analyses, since the panels have been so far typically considered only as a part of the mass of the structure, while their influence to the stiffness and the global response of the precast building has been typically neglected. It was found that the influence of the panels to the response of the whole structure depends significantly on the type of all four connections. In the first phase of the analysis the influence of the most common sliding connections to the response of panels and whole building was analysed. The seismic demand of cladding panels and their connections to main structural system of industrial buildings have been defined for the first time. This data, together with properly estimated seismic capacity (see previous socio-economic achievement) enable development of the methodology for estimation of the level of the seismic vulnerability of industrial buildings, identification of those buildings where the seismic strengthening should be provided, and the identification of optimal strengthening procedures. In this way a relatively small investment into the increased seismic safety will prevent huge direct and indirect cost due to the collapse of panels, which was clearly demonstrated during the last earthquakes in Italy.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 6519905In the nuclear power plant Krško (NEK) the seismic resistance is continuously checked by taking into account the latest available data and modern methods of analysis. The research team at FGG, involved in earthquake engineering, has successfully collaborated with the NPP Krško for many years, especially in reviewing and assessing projects that are related to the seismic safety of NPP facilities and their equipment. The report contains the results of an independent evaluation of a project, conducted by a U.S. company, comprising the determination of floor spectra for all objects of the nuclear island at increased seismic loading (maximum ground acceleration of 0.6g, 0.7g and 0.8g). Floor spectra were calculated also for the Essential Service Water Intake Structure (ESWIS) and the new building for the new diesel generator. In separate reports the structural displacements were determined for all facilities. The methods of analysis used and the obtained results were summarized in the new version of the update safety analysis report (USAR). Within the review procedure, we developed, independently of the contractors, the mathematical model of the buildings of the nuclear island and of the diesel generator building and conducted several independent control analyses. It would not be possible to achieve a high quality of the review work without the knowledge generated in research in the field of earthquake engineering. A number of review reports have been prepared, of which only some are included in COBISS (in addition to the numbers in the heading, also COBISS.SI-ID numbers 6466401, 6465889, 6465633, 6466657, 6466145, 6466913)
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 6465377The report presents and analyses results of non-standardised friction tests carried out on 9 different sets composed of thermal isolative FIBRAN boards made of extruded polystyrene foam (400-L or 700-L product; one board with thickness of 200 mm or two boards with thickness of 120 mm at the 400-L or 100 mm at the 700-L) and concrete slab, and in particular variants also with hydro insulation or polyethylene foil (TI sets). The testing assembly used enables application of selected pre-compression on the TI set in vertical direction (in our case 50kPa, 100kPa, 200kPa and 300kPa) and inducing of displacements with help of hydraulic actuator INSTRON with capacity of 250 kN in horizontal direction. With help of LVDTs on selected measuring points of the TI set displacements and deformations were measured in order to determine contact/contacts between elements of the TI set where sliding occurred. Based on the tests’ results the most optimal TI set below concrete foundations was selected and upgraded with ribs as part of the FIBRAN boards. FIBRAN board containing ribs was designed in order to obtain higher resistance of buildings with the TI set below the concrete foundation against sliding in case of earthquake.
F.07 Improvements to an existing product
COBISS.SI-ID: 6530657The principal investigator is one of the three editors of the international journal Earthquake Engineering and Structural Dynamics (Wiley) with the highest impact factor among the journals in the field of earthquake engineering. In 2013, he processed 135 manuscripts submitted for publication. Editorial work provides an overview of research performed worldwide and also enables some influence on the directions of future research. The principal investigator is also a member of editorial boards of five other international journals.
C.04 Editorial board of an international magazine