Civil and Environmental Engineering

 

Date of this Version

Summer 7-31-2013

Citation

APA

Comments

A THESIS PRESENTED TO THE FACULTY OF THE GRADUATE COLLEGE AT THE UNIVERSITY OF NEBRASKA IN PARTIAL FULFILLMENT OF REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE, MAJOR: CIVIL ENGINEERING, UNDER THE SUPERVISION OF PROFESSOR MARIA SZERSZEN. LINCOLN, NEBRASKA: JULY, 2013

Copyright (c) 2013 Ali Alhajami

Abstract

Bearing capacity of shallow foundation is one of the most challenging problems for engineers. The difficulty comes from multiple sources of variability and uncertainty. There is an uncertainty in live load. Soil properties including: unit weight, cohesion, and angle of friction represent sources of variability in the determining bearing capacity. The current theories used in practice only estimate bearing capacity and does not give an exact value for it because of these sources of variability. Currently, there are Terzaghi, Meyerhof, Vesic, and Hansen theories for dealing with this problem. Based on previous research Terzaghi theory was found to be the most close estimation tool to the real value of bearing capacity.

The aim of this paper is to calculate the reliability index of Terzaghi’s theory and to propose a resistance factor that corresponds a reliability index of 4. The reliability analysis was done for circular and square footing. Loads, soil properties, width, and depth of the foundation were considered random variables to get a complete picture of the bearing capacity problem. The reliability analysis was done using Monte Carlo simulation and the First order Second Moment method to calculate the reliability index.

Advisor: Maria Szerszen

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