Symmetric junction manholes under supercritical flow conditions By Juan Saldarriaga, Gina Rincon, Gloria Moscote and Maria Trujillo

The present Discussion aims to evaluate the applicability of the empirical criteria defined for symmetric four-branched junction manholes in the Technical Note. These recommendations are herein used to estimate the maximum shock wave heights and the discharge capacity of 45° and 90° three-branched supercritical junction manholes with variable inlet branch diameters. The equations reported in the Technical Note are assessed by considering the experimental data collected by Del Giudice and Hager (2001), Gisonni and Hager (2002), Gökok (2013), Niedermann (2013) and Crispino et al. (2019). All these research studies analysed junction manholes approached by two circular inlet branches and with a circular outlet branch (subscript u) of diameter Du = 0.240 m. The manhole cross-section was U-shaped, as in the Technical Note, and the side benches had a fixed height of dB = 1.50 Du. In the following, Q is the discharge, h is the flow depth (as well as the shock wave height) and y = h/D is the filling ratio.