Behaviour factor and displacement amplification factor for the seismic design of single-layer barrel vaults

Behavior factor and displacement amplification factor play an important role in the seismic design of structures. In the previous research investigations, no attention has been paid to study these factors for single-layer barrel vaults, and these factors have not been specified for these structures in seismic design codes. Therefore, in this paper, special attention is focused on the determination of the seismic response modification factors for this type of structures. This paper aims to investigate the mentioned factors considering the effect of the parameters of the rise-to-span ratio and the length of the structure. To this end, 15 single-layer barrel vaults with different rise-to-span ratios and different lengths were designed and these factors together with the ductility and over-strength factors were computed and discussed in detail. The results indicate that the seismic response modification factors are dependent on the rise-to-span ratio and are almost small. Finally, by means of the regression analysis implemented on the results extracted, two equations were presented individually in terms of the rise-to-span ratio to obtain the behavior factor and displacement amplification factor for single-layer barrel vault structures. Furthermore, an equation was proposed in terms of the height of the structure to compute the fundamental period of this type of structures. A criterion was presented for the determination of the target displacement at the reference point in the pushover analysis corresponding to the design basis earthquake (DBE) level as well.