Bridge-Column Footings: An Improved Design Procedure

Abstract

The aim of this paper is to discuss and improve on the current highway bridge-footing design procedure. Five California highway-bridge-column footings are presented here as examples, and are analyzed by using both the current Caltrans design procedure and the proposed method, considering moments induced by lateral forces and footing depth. Considerations of passive soil pressure on the side of footings are also discussed in these case studies. The current Caltrans design procedure of neglecting moments induced by lateral forces and footing depth underestimates the soil/pile bearing reactions by about 16–78% for compression, about 27–47% for tension, about 17–75% for flexure bending moment for designing bottom reinforcement, and about 26–58% flexure bending moment for designing top reinforcement. The larger the footing depth and/or the shorter the column, the more unconservative the current design procedure.