Full-scale testing of corrugated fibreboard shelter subjected to static-equivalent wind loads

Abstract

DuraKit Shelters Inc. has developed a modular house for emergency, temporary or semi-permanent occupation that uses corrugated fibreboard as the main structural material. The houses are marketed internationally and so must resist tropical cyclone wind loadings. Two full-scale shelters, measuring 4.9 m×6.1 m in plan, were subjected to static forces equivalent to loads caused by wind acting normal to the ridge of the roof. Five areas of each full-size specimen were independently loaded using a large test facility built in 5 days on a rural outdoor site for a cost of approximately Cdn$8000. The testing illustrated strengths and weaknesses in the design and construction of both the shelter and the testing apparatus. The shelter generally performed well, but was susceptible to premature local failures in regions where tension was applied through the thickness of corrugated fibreboard panels or where the quality of construction was imperfect. The testing apparatus also generally performed well, once its connections to the specimen were modified to eliminate localized areas of high stress and the relatively large deformation of the specimen were accommodated. Failure of the second specimen initiated at the roof-to-wall connection of the windward wall when the applied load reached 73% of the pressures caused by tropical cyclone winds. Roof deflections observed on the full-scale shelter agree reasonably with those predicted using finite element analysis. The observed deflections were greater than the predicted values, and the discrepancy can be attributed to creep and other effects not considered in the finite element analysis. This suggests that finite element modeling is an appropriate tool for investigating the behaviour of corrugated fibreboard structures.