Construction of the Santa Isabel hydro project in central Bolivia was completed in 1973. The project includes a penstock, with the lower half comprising an unusual hyperstatic design with no expansion joints and anchors at alternate bends. The penstock was designed for a static head of 864 m plus 15% waterhammer. It burst when filled with water on March 16th, 1973 at a head of 735 m. Cause of the failure was attributed to an improper weld at an unsupported bend in the hyperstatic section of the penstock. Construction of a second parallel penstock was completed and commissioned in March 1981. This paper describes the work undertaken to guard against a repetition of the 1973 failure, compares the isostatic design (with expansion joints) of the upper half of the penstock with the hyperstatic design of the lower half of the penstock, outlines design procedures, and describes construction methods used for installation of the second penstock.