Journal of Civil Engineering Researchers
Volume:1 Issue: 5, 2017

During an earthquake, there are two main effectual factors causing damage to structural and non-structural members; The two factors are relative lateral displacements of stories (drift) and absolute acceleration of stories. In this study, seismic isolators have been considered as a solution for dealing with damages and their causing factors, because they can both decrease the relative lateral displacements and absolute acceleration of stories significantly. Consideration of a 5 story building which was modeled in ETABS software, showed that using a system of lead rubber bearing base isolator(LRB) can significantly reduce the relative displacements and shear forces of stories (on average, about 50%); so the structural designleads to the optimal degree.

In this study a 10-storey building of reinforced concrete moment frame is designed as isolated and fixed-base. Lead-rubber bearing (LRB) is used as an isolation system.In order to consider the actual behavier of structure ,Nonlinear behavior of both isolation system and structure areconsidered in the modeling. The behaviors of designed models under dynamic loads are analyzed using SAP2000 software. At the end of analysis, period, storey acceleration, inter-storey drifts, base shear forces, volume of concrete and weight of rebards are compared for isolated and fixed-base structures.

in this review, we study the effect of H/D ratio of core diameter on concrete core strength. It has been shown that the compressive strength of cylinderical concrete specimen grows up as the height –to-diameter ratio decreases. In fact, the strength correction factors are responsible for evaluating this feature shown in ASTMC42 and BS1881 although we can not apply it to high-strength concrete over 40 MPa. For this purpose, concrete core specimens of 100 mm diameter were cut into different lengths with respect to the following height-to-diameter ratios 1.0,1.25, 1.5, 1.75 and2.0. The results showed that strength reduces when L/D ratio rises. Also, for various strength classes, the correction coefficients of L/D are different.