Design Charts for Minor Service Structure Foundations (506-1F)

This report presents a series of design charts which allow an entirely graphical procedure to be followed in selecting the proper size of drilled shaft foundation for standard Texas Highway Department signs. The procedure uses a boring log of Texas Highway Department cone penetrometer measurements and a graphical overlay-slide device which was developed in this project to determine the soil shear strength parameters, c and ¢. These data are used to select one of five typical soil types which span the range of soil properties normally encountered and this determines the footing design chart to use. The footing is sized to carry the moment for which the sign support column is designed.|The procedure is simple, and while only an approximation of the more complex and more exact theory developed and verified in Research Study 2-5-67-105 "Design of Footings for Minor Service Structures," it will produce designs that are slightly more conservative than those given by the more exact theory.|A detailed discussion of the assumptions involved is given and a user's guide is presented. Recommendations are made on how to design footings to rest in a non-uniform soil profile. There are 21 design charts which have been tailored for Texas Highway Department design standards but five additional basic design charts permit the design of footings for non-standard sign supports.