Author: Shad M. Sargand

Publisher:

Published: 2006

Total Pages: 338

ISBN-13:

Spread footing foundations have been used to support various types of civil engineering structures over the years. However, one type of structure to which they have not seen much widespread application is highway bridges. This is because bridge engineers generally take a rather conservative approach and specify deep foundations, such as H-piles and drilled pier shafts, to support the bridge superstructure weight and live loads. In the current research project, the ORITE team continued to investigate several technical aspects related to spread footing foundations. Four additional spread footings constructed at two interstate highway construction sites were instrumented with modern sensors and monitored through construction stages and beyond. The spread footing design methods presented in the AASHTO LRFD Bridge Design Specifications (2004) were validated on the basis of the field performance data accumulated during the ORITE research project(s). Twelve SPT-based settlement prediction methods (for footings resting on cohesionless or slightly cohesive soils) were evaluated in light of the field performance data. General performance analysis of spread footing foundations at bridge construction sites was made to draw some guidelines concerning the use of spread footings for supporting highway bridge structures. Finally, detailed cost comparisons were made between spread footing and pile foundation options. Overall, the results of the research project indicated that: 1) spread footing can be a viable option as the highway bridge foundation; and 2) the design methods presented in the AASHTO LRFD Bridge Design Specifications (2004) appear to be satisfactory.