Quantitative comparison of 2D and 3D modeling for concrete gravity dams

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2014


Supervisor: YALIN ARICI


Seismic behavior of gravity dams has long been evaluated and predicted using a representative 2D monolith for the dam. Formulated for the gravity dams built in wide-canyons, the assumption is nevertheless utilized extensively for almost all concrete dams due to the established procedures in 2D space as well as the expected computational costs of building a three dimensional model. A significant number of roller compacted concrete dams are being designed based on these procedures regardless of the valley dimensions, joint-spacing or joint details. Based on the premise that the assumption is overstretched for practical purposes in a variety of settings, the purpose of this study is to critically evaluate the behavior of monoliths within a dam and determine the representativeness of this assumption. A generic 80m high dam was considered in different valley settings, corresponding to multiples of the dam height. For a range of selected ground motions, the difference between the responses of individual monoliths to the full monolithic dam solution was compared in a 3D analyses setting. The results were compared to the commonly used 2D solutions. The results showed that the 2D assumption generally yielded better estimates to the 3D case for the independent monoliths and wide valleys whereas it showed large discrepancies with respect to 3D models for the fully monolithic case and narrow valleys.