This book aims to present the research that has been done and is in progress in the world today on the use of post tensioning with tendons for steel trusses. The focus is on external prestressing and strengthening with tendons. The objective is to find the reduction in forces of the truss members and weight of the truss by the post tensioning. Also the reduction in amount of cost savings using post tensioning can be estimate. It also describes the methods used in accomplishing this maintenance and repair work.