- As ecoroofs have become more widespread throughout the U.S., it has become increasingly important to understand their structural behavior. The purpose of this research was to investigate the load effects exerted on a roof structure with an ecoroof during rain events and the subsequent drainage period, with the intention of using this information in the development of a structural specification for the design of ecoroofs. Research consisted of the construction of a full-scale ecoroof specimen, with a slope of 0.25/12, which was subjected to four tests where structural behavior was observed. Two tests investigated structural effects while the ecoroof freely drained, and two observed the structural effects while the drain was blocked and water was impounded on the ecoroof. Following experimental
research, a model was used to investigate the second-order effects associated with hydraulically loaded ecoroofs, and a moment amplification factor was developed to aid in the consideration of second-order effects during the ecoroof structural design process. Experimental results showed that structural responses were minimal during events were free drainage occurred. Analytical results showed that the moment amplification for sloped hydraulically loaded roofs converges towards the moment amplification value associated with a flat roof with the same structural characteristics as the height of the impounded water on the roof increases. Additionally, second-order moment amplification is inversely related to EI/L4. Recommendations for design center around the adaptation of a new load category, termed a transient water live load, which accounts for the difference in load between the ecoroof at a drained state, and at a saturated state.