نوع مقاله : مقاله پژوهشی
موضوعات
عنوان مقاله English
نویسندگان English
It is obvious that surface roughness should be considered in seismic calculations due to their many effects on seismic response of sites. In this paper, the combined effect of slope angle of hill material layers and height in alternating topography under the influence of Landers earthquake for two geometry of semi-circle and trapezoidal hills is using finite difference method is presented. Due to dynamic interaction between the hills, alternating topographic displacement is larger than single topography. For example, a single hill with a height of 30 meters has an amplification of approximately 1.79 at an angle of 15 degrees while at the same height and angle, the triple sine hill has experienced an amplification of 1.97. Then, the effect of density, elasticity modulus and Poisson ratio of materials on seismic motion of hills with non-horizontal layered materials is investigated. With increasing density and Poisson ratio, alone, seismic amplification increased but changes in the amount of elasticity modulus alone did not affect the magnification. Differences in layering due to Poison Ratio had negligible effect on amplification. The hill’s height is an important parameter that effects on amplification responses. As height increases, the amplification increases too. Another important parameters are number of adjacent hills, height of adjacent hill and also the distance between the hills. The more height hill adjacent to the base hill, the more amplification for the base hill. The obtained results demonstrate that as the height of the hill increases, the effect of different angles of layering increases on amplification of the base hill. It means that although the hill’s height is an important parameter, but also this parameter directly increases the effect of the angle between layers of the hill on amplification and seismic response of the hill. It is very important to consider these effects for design the structures located on these hills. Another important parameter that is studied in this research is the mass density of the hill’s material. The mass density has an increasing effect on seismic response of the hill; as the mass density of the hill material increases, the amplification increases. This means that as the weight of the hill increases, the amplification increases; as it is also an important matter in seismic behavior of different buildings in seismic codes. Obtained results show that elasticity modulus of the soil does not have any important effect when the angle between the soil layers are investigated.
کلیدواژهها English