Abstract :
Concrete tower foundations of mushroom type, requiring no forms or back filling, as used in recent Baltimore-Holtwood transmission line, are found to be cheaper and stronger than steel tripod foundations previously used in a similar line alongside. It was found that mushroom type concrete foundations could be built with a smaller construction force and at lower cost, and more rapidly, than certain types of concrete foundations requiring forms and back filling. The procedure of digging holes and concreting of mushroom type foundations is described. Method of erecting transmission towers by the use of a shear leg is described in some detail.