The first in a series of testing programs at CU Boulder CIEST investigating performance of critical lifeline systems under extreme loading conditions. This study focuses on the response of various thermoplastic pipe materials and a coupling connection under externally applied axial and lateral loading. Internally pressurized, 6-in. (150-mm) diameter specimens were tested to failure under various loading scenarios including axial tension, compression, and cyclic loading as well as transverse 4-pt bending. This project initiated the development of self-reacting test frame capable of applying dynamic tension and/or compressive loading in excess of 100,000 lbs to linear structures up to 12 ft long. CIEST’s 1,000,000 lb four-post load frame was employed to apply lateral loading.