www.cafetinnova.org Indexed in Scopus Compendex and Geobase Elsevier, Chemical Abstract Services-USA, Geo-Ref Information Services-USA, List B of Scientific Journals, Poland, Directory of Research Journals ISSN 0974-5904, Volume 07, No. 04 August 2014, P.P.650-654 #SPL02070422 Copyright ©2014 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved. Proceedings of 3-Day International Conference on Emerging Trends in Civil Engineering (ICETE-2014,) 6th–8th January, 2014 Dynamic Analysis of RCC Cantilever Retaining Wall with Different Parameters P. R. JAGTAP 1 , S. M. PORE 1 AND VIPUL PRAKASH 2 1 Department of Civil Engineering, Dr. Babasaheb Ambedkar Technological University Lonere, Dist- Raigad- 402103, Maharashtra, India 2 Department of Civil Engineering, IIT Roorkee-247667, India Email: prjagtap26@gmail.com, struct_engg@yahoo.co.in, spvpgp@gmail.com Abstract: For the safe and economic design of retaining structures, correct estimation of earth pressure on retaining surfaces is very important. Due to analysis complexities, this problem has drawn attention of researchers from last few decades. Even under static conditions this is one of the most critical and complex problems of soil mechanics and geotechnical engineering. Dynamic loading conditions make the problem further complicated. In this paper, a method is studied to obtain the natural time period of a retaining wall both for active and passive earth pressure condition and the dynamic analysis of such a wall is carried out. Time period of RCC cantilever retaining wall is found out from derived natural time period formula. Shear force and bending moment at the base of retaining wall is obtained with the help of time period and parameters such as height of wall and unit weight of retained soil. Parametric study shows that these are most influencing parameters affecting behaviour of retaining wall. Keywords: Retaining wall, time period, earth pressure, shear force, bending moment. 1. Introduction: Most important consideration in proper design and installation of retaining walls is that the retained material is attempting to move forward and down slope due to gravity. This creates lateral earth pressure behind the wall which depends on the angle of internal friction (phi) and the cohesive strength (c) of the retained material, as well as the direction and magnitude of movement the retaining structure undergoes. Present state-of-the-art for the analysis and design of retaining walls under earthquake loading is based on the method proposed by Mononobe and Matsuo (1929) [8] and Okabe (1926) [9] (M-O analysis). Also the Indian Code of Practice, IS- 1893 [6] suggests the use of α h and α v based on seismic coefficient to any time-period calculation, which could again make the analysis far too conservative. As IS-1893 does not provide any rational method for calculation of natural period of the retaining wall, seismic analysis for such system is still based on what one can term as a pseudo static analysis. Many analysis have come up for the solution of such problems based on Finite Element Method. The basic lacuna in most of these analyses is that the earth pressure is generated under incipient failure of the soil medium. In this paper, a method is studied to obtain the natural time period of a retaining wall quite accurately and to carry out a dynamic analysis of such wall based on modal response technique. The parametric study of natural period of retaining wall is carried out by varying the different parameter like height, unit weight of soil, angle of internal friction of soil, thickness of wall and grade of concrete. The dynamic shear force and bending moment are derived based on modal response technique by lumped mass system and the same is compared with the static shear force and bending moment of retaining wall. 2. Analytical Work For the safe and economic design of retaining structures, correct estimation of earth pressure on retaining is very important to civil engineers. Due to its complexity in analysis, this problem has drawn the attention of researchers through the decades. Even under static conditions this is one of the most critical and complex problems of soil mechanics and geotechnical engineering. So, under dynamic condition and under seismic loading, the problem is no doubt challenging. Among the theories available till date for the estimation of seismic earth pressure, the Mononobe–Okabe (1929, 1926) method, which is the pioneering work in this field, is commonly used. 2.1. M-O Analysis The total forces on the wall under active as well as passive earth pressure conditions are as per [8] and [9]