Full-scale field test for buried glass-fiber reinforced plastic pipe with large diameter

In this paper, we present the result of full-scale field test for buried glass fiber reinforced thermosetting polymer plastic (GFRP) pipes with large diameter (inner diameter of 2400 mm). Installation of pipe takes 10 days to complete 16 m depth backfilling layer by layer. The vertical and horizontal ring deflections are measured for 387 days. The short-term deflection measured by the field test is compared with the result predicted by the Iowa formula and the finite-difference analysis (FDA). As a result, the value calculated by the Iowa formula tends to overestimate to a considerable extent. Vertical and horizontal ring deflections calculated by the FDA agreed with test results. In addition, the long-term ring deflection is predicted by using the procedure suggested in ASTM D 5365 in the range of 40-60 years of service life of the pipe based on the experimental results. From the study, it was found that the long-term vertical ring deflection up to 60 years is less than the 5% ring deflection limitation.