Volume 11 (2015): Issue 2 (May 2015)

A 3000 tones capacity silo, located in a seismic area with ground acceleration a_g = 0,20g and T_C =1,0s, was designed in a classical solution The supporting structure has an octagonal shape in planview, and columns with “Maltese cross sections”. The main lateral resisting system is made up of centric bracings with cross-section class I.

The technological project has required two silos and the solution was to support them on a common raft foundation. The stresses and strains due the seismic action led to material consumption that exceeded the agreed budget. In order to reduce the costs, two versions of isolator positions were studied: base isolators (at the connection between infrastructure and superstructure) and at the silo’s bearing level on the supporting structure.

A number of eight vertical seismic isolators were used and in order to limit the horizontal displacements due to wind action and for small intensity earthquakes special devices were introduced

Comparing the state of stresses and deformations and also the cost analysis regarding the positioning of the isolators, the second solution was chosen as the most feasible.

The paper presents a study case and highlights the changes made by the new, in force, seismic Code P100-1/2013 in comparison with the former P100-1/2006, concerning the reinforced concrete frame structural systems design. Different seismic designed RC frames systems, compatible with modern office requirements, were studied. The influence of the earthquake codes provisions on design of regular buildings, having openings fitted for open spaces, with a story height of 3.50m, was assessed. The benefits of tubular structures, with rigid frames made of closely spaced columns on the building perimeter, were analyzed as well. The results of the study case are presented emphasizing the consequences of the application of the new seismic Code on the computation of the reinforced concrete frame structures.

The paper presents the Spectral Representation Theorem of a stationary process and two simulation methods derived from it. In order to test the accuracy of the two simulation methods two numerical applications are employed. First, using a theoretical power spectral density (PSD), two sets of sample functions, corresponding to each method, are generated and a comparison of the obtained numerical results with the analytical PSD is carried out. The second example is more complex and consists in using the stationary zone of the strong motion of the recorded NS acceleration registered at INCERC during the 1977 Vrancea earthquake. The corresponding Fourier Spectrum is calculated. In order to obtain a smoother PSD representation for the real Fourier spectrum, a specific barrier model spectrum (SBM) is fitted to it and the corresponding PSD calculated. This PSD is used to generate two sets of samples. The mean PSD obtained using both methods of simulation is compared with that characterizing the registered acceleration. The paper shows that the generated time series possess all the theoretical probabilistic characteristics discussed below, when the number of terms used in the simulation formulas is large. Three types of estimators are employed in the numerical evaluation of both simulation methods

One of the most destructive natural phenomena is the earthquake. These events destroy lives, goods and disrupt human activities. For this reason the anti-seismic protection of buildings is a very important and of interest subject in Civil Engineering. In the case of structures with a low seismic energy dissipation capacity (for example steel frame structures with Slimdek composite floors), this problem becomes more complicated due to the requirement of dampers. In this paper an experimental study is presented regarding an innovative yielding metallic energy dissipation device, proposed by the author. An experiment is carried out on a shake table. By studying the results from the experiments and from the previous carried out numerical analysis we can conclude that this device provides a high anti-seismic protection for this type of structures.