ROCK SOCKET TRANSMISSION-LINE FOUNDATION PERFORMANCE

A major goal of overhead transmission line design is to achieve a mini mum cost for a given level of reliability and safety. The greatest unc ertainty in this process is in foundation design. Recognizing this opp ortunity to improve the economics of transmission line design, the Ele ctric Power Research Institute (EPRI) has sponsored, since 1977, a com prehensive program of activities in foundation design. Since little hi gh quality foundation test data existed, a recent task involved perfor ming well documented full-scale load tests of drilled shafts and direc t embedment Pole foundations for single transmission line poles partia lly or totally socketed in rock and subjected to high lateral forces a nd overturning moments. A summary of the results obtained for fourteen load tests is presented. Based on the load tests , a provisional desi gn guideline is also proposed.