Seismic Reliability-Based Design Versus Safety-Factor Based Design of Shallow Foundations Near a slope

Document Type : Research


1 Ph.D. Student, School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, USA.

2 Associate Professor, Geotechnical Engineering Research Center, International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, IRAN.

3 Postdoctoral Fellow, School of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran.


In this study, the stability of the foundation near a slope is investigated through a typical example of designing a shallow foundation. Foundation stability is typically evaluated through the bearing capacity’s factor of safety and the reliability of the design, which depicts a more realistic perspective of design safety. Although an increase in the bearing capacity of the foundation leads to a subsequent increase in the safety factor and reliability index, a monotonically increasing functional relationship between the safety factor and reliability does not exist. This study investigates the effects of the foundation and slope properties on the Reliability-based Design (RBD) and Safety-Factor Based Design (SBD). Also, some valuable hints for practical engineers” who are not familiar with reliability concepts” are presented to achieve a more reliable SBD. The results show that it is vital to consider how to increase the bearing capacity in the SBD methods. For example, in cohesive-frictional soils, by changing the embedment depth of the foundation (df), and the distance between the foundation and slope crest (x) to reach the target safety factor, we can obtain a more reliable SBD.


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