Floodway Design Process Revisited

Abstract

Floodways are small road structures that are meant to be overtopped by floodwater during a flood event with relatively low average recurrence interval and expected to be in complete functional stage after the flood water recedes. The severity of 2011 and 2013 flood events in Queensland damaged the floodways in the state causing a huge impact mainly to the rural community during the recovery and rehabilitation stage. Therefore, the resilience of these small critical road structures is of great importance for the survival, safety and recovery stages during such events. Using a case study region in Lockyer Valley Regional Council area, the authors found that majority of the structural damage was caused due to the heavy impact load from the boulders/logs that came with the flood water. Another aspect reviewed was the damage sustained by floodway aprons due to excessive debris loading. This is of particular concern since aprons are the most expensive component of a floodway to repair or replace. Since floodways encounter many forces throughout their service life thorough review and investigation of current design standards are required in order to improve floodway resilience. In an attempt to develop a floodway design process, this paper focusses on the analysis of two types of floodways and reports the procedure used to develop design charts. Detailed finite element analysis is demonstrated by using one type of floodway. Finally, the contribution that resulted from the structural analysis is linked with the current floodway design guide.

A Pioneering Integration of Structural Health Assessments and Dynamic Analyses: Bridge Pier Responses to the Impact of Floating Objects during Extreme Floods

“…Based on empirical evidence, studies on the dynamic behavior of logs as floating objects in relation to hydraulic structures have highlighted their considerable kinetic energy, resulting from their substantial mass and accelerated movement within floodwater currents. This presents a notable risk to the structural stability of bridge piers, particularly during flood events and log impact [1,[14][15][16].…”

Structural design of floodways under extreme flood loading

“…This research, through the undertaking of a Finite Element Methods approach expands on the authors conference paper titled "Floodway Design Process Revisited" (Greene et al, 2019) to deduce what causes a standard engineering floodway type to be most vulnerable, while acting in a frequently submerged state. Utilising this state of vulnerability as the basis of design, ultimate design bending moments and shear forces can be determined and structural design charts deduced.…”