Modified Frye–Morris polynomial model for double web-angle connections

The polynomial model proposed by Frye–Morris is generally used to predict the moment-rotation behaviour of eight types of angle connections. The problem with the Frye–Morris model is that it either overestimates or underestimates the connection stiffness as it was developed by assimilating only few test results. A nominal air-gap distance of 10 mm is provided between beam and column, while assembling the connections for fabrication conveniences. This air-gap distance has considerable influence on the connection behaviour observed from the previous studies and an improved polynomial model was suggested for top and seat-angle connection based on the numerical parametric studies by considering the air-gap distance as an additional size parameter. In line with this, the Frye–Morris model for double web-angle connection is also modified based on numerical parametric studies. A new equation is proposed based on the Frye–Morris procedure with air gap as an additional parameter. The proposed equation is compared with the experimental results and Frye–Morris model and is found to be in close agreement.