Dynamic loading effects on overhead lines- Impact on foundations

The Technical Brochure (TB) presents an overview of various factors that the line engineer needs to understand and consider in designing overhead line foundations under quasi-static rapid/cyclic loadings or under full dynamic loadings. Results from several full-scale foundation tests under rapid uplift loadings indicate that the foundation capacity can be increased by about 25% - 40%. Foundation uplift capacity on cohesive soils is increased significantly because of the suction beneath the foundation. Under cyclic load tests on grillage foundations, the foundation deformation stabilizes (shakedown) after several load cycles even if it has accumulated some permanent strain, provided the loading amplitude is kept below a static threshold value. Results from a full dynamic analysis…