Utjecaj vertikalne komponente potresa na AB nosače velikog raspona

Abstract

Most of the previous studies in the field of earthquake engineering have neglected the effects of vertical ground motion and are usually guided by horizontal motion. The EN1998 proposes action analysis of the vertical acceleration for certain types of elements and their length and their distance from the active fault. In this paper simply supported beams with various spans, 10, 15 and 20 m, are calculated for the action of real earthquakes with different intensities. Two typical cross sections were chosen: "T" cross section and rectangular cross section. The linear and nonlinear material models were used, and all the models were calculated using rigid and elastic supports. Through the combinations of these different spans, cross sections, material models and types of the supports, the influence and importance of the vertical component of the ground motion is estimated. Based on the results obtained it was concluded that there is a need for the application of vertical acceleration in the seismic analysis of these elements.Dosadašnja su ispitivanja učinaka potresa zanemarivala vertikalno gibanje tla te se uglavnom usmjeravala prema horizontalnoj komponenti. EN1998 daje preporuku analize djelovanja vertikalnog ubrzanja za određene vrste elemenata i njihovih duljina te njihove udaljenosti od aktivnog rasjeda. U radu se analiziraju jednostavno oslonjeni nosači različitih raspona, 10, 15, 20 m te pravokutnog i "T" poprečnog presjeka. Primijenjena su dva tipa oslanjanja, kruti i elastični ležaj te dva tipa modela materijala, linearni i nelinearni. Nosači su podvrgnuti djelovanju četiri realna potresa različitog intenziteta. Na ovaj se način pratila promjena u momentima savijanja nosača u polovici raspona kako bi se vidio doprinos vertikalnog ubrzanja. Na temelju dobivenih rezultata zaključeno je kako za analizirane nosače ipak postoji potreba primjene vertikalne akceleracije prilikom seizmičke analize