In many buildings the centres of resistance do not coincide with the centres of mass. As a consequence, lateral base motion during an earthquake gives rise to torsional vibration of the structure. The inelastic seismic behaviour of asymmetric-plan buildings is considered using the histories of base shear and torque. The procedure to construct the base shear and torque (BST) surface of the system with an arbitrary number of resisting elements in the direction of asymmetry and of ground motion is proposed. The factors that determine the shape of the BST surface are the strength eccentricity, lateral and torsional capacity of the system and planwise distribution of strength. The BST surface contains most of information necessary to describe the inelastic properties of a system. However, the inelastic deformation cannot be computed unless a nonlinear static or dynamic analysis is performed

No abstract

The paper presents methodology for safety assessment and design of earthquake resistant structures based on application of damage spectra. The damage spectrum can be used for seismic evaluation of vulnerability of structures with given properties and can provide information of damage potential of the recorded ground motions. Damage spectrum represents a variation of a damage index versus structural period for a single-degree-of-freedom system subjected to an earthquake ground motion. The improved damage index, based on plastic deformation and hysteretic energy dissipation, is applied. It depends on maximal plastic deformation, ductility capacity and function including cumulative damage effects. This function, besides the parameter including influence of deterioration, depends on the history of cyclic deformations and on both cyclic and accumulative ductility

<p>The paper deals with design proposal of new roadway bridge across the Danube in Novi Sad, with an overall length of 545 m, having the spans: 40,0+40,0+50,0+50,0+91,7+188,3+85 m. The bridge deck, width of 23,5 m, carries 4 lanes of vehicular traffic and two lanes of pedestrian/ cycleway.</p><p>The main bridge part is an asymmetric cable-stayed structure, with a main span of 188,3 m and a back span of 91,7 m. The unique single pylon of the original curved shape and height of 59,5 m is rigidly fixed into the deck. The stays of harp configuration are in middle plane. The aesthetics plays a major role in bridge design to be a meeting point for engineering and architecture. The proposed bridge has an original architectural appearance well incorporated in Novi Sad city environment of plane left bank and the hilly right bank with old Patrovaradin Fortress. This is a feasible original bridge design concept from structural point of view as well.</p>

Eurocode 8 spectra are scaled by the peak ground acceleration values that are defined for the given site through a probabilistic seismic hazard analyses (PSHA). However, spectra that are created by combining the empirical shapes with the single PSHA-defined scaling factor will not represent the so-called Uniform Hazard Spectra (UHS). Moreover, the very shape (Type 1 or Type 2) of the Eurocode 8 elastic spectrum is selected with respect to the magnitude of the earthquakes “that will contribute most to the seismic hazard defined for the purpose of probabilistic hazard assessment…”. Such definition is somewhat obscure since these “most contributing” earthquakes are, even at the same site and for the same probability i.e. for the same “return period”, different (in a general case) for different vibration periods, while the whole Eurocode 8 spectrum is scaled by using only the PSHA estimate of the peak ground acceleration. In this Paper we present an illustrative example of the Uniform Hazard Spectra for the city of Belgrade and compare the obtained UHS spectra, as well as the scenario empirical spectra scaled for different earthquake parameters, to the corresponding Eurocode 8 spectra, further pointing out the intrinsic ambiguities in the current EC8 suggestions for creation of design spectra. [Projekat Ministarstva nauke Republike Srbije, br. 36043