Science and Education Publishing American Journal of Civil Engineering and Architecture 2328-7357 2 5 2014 10 08 The Investigation of Effective Parameters on the Stability of Concrete Gravity Dams with Case Study on Folsom, Blue Stone, and Pine Flat Dams 167 173 EN Elyas behradimehr Department of Civil Engineering, Master of civil Engineering, young researchers and elite club, roudehen branch, islamic azad university, roudehen, Iran afshin mansouri babak aminnejad mohammad ali barkhordari bafghi AJCEA2014253 10.12691/ajcea-2-5-3 2014 09 10 2014 09 25 2014 10 08 In this research, the effective parameters in stability of concrete gravity dams in the form of case study on three important dams: Blue stone; Folsom; and Pine Flat, are investigated. Typically, cognition and understanding of effective parameters in stability and knowing the role of each them, in designing new dams, could be very helpful. Concrete gravity dams (which are surveyed in this research) have their strength and stability because of their weight. The shape of their section are triangle and commonly, The base of the triangle is greater than the dam is stable, the more stable dam is. Also, in this investigation we are going to study the horizontal displacement called sliding of dam's bottom, in contact with foundation by ABAQUS software. The sliding displacement has no considerable change in each of the three nodes on heel and toe, and also in middle part of dam, and eventually is equal in each three and all parts of the dam's bottom and foundation. With choosing three nodes on the dam's bottom and similar nodes on the foundation, and with differentiating horizontal displacements of these nodes with each other, the relative displacements of dam are obtained. With using these displacements acquired from ABAQUS software in RS-DAM software, we show them as time series graph and relative displacement. Whenever this graph has a jump with the increase of earthquake PGAs (end of the graph moves away from the starting point of it), dams is considered as unstable.