@article {bnh-4211, title = {Cost-effective mitigation strategy for flood prone buildings: annual project report 2016-17}, number = {333}, year = {2017}, month = {09/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The motivation for this project arises from the experience and observations made during the 2011 and 2013 floods in Australia, which caused widespread devastation in Queensland. The flood events also resulted in significant logistics for emergency management and disruption to communities. Considerable costs were sustained by all levels of government and property owners to effect damage repair and enable community recovery.

A fundamental reason for this damage was inappropriate development in floodplains and a legacy of high risk building stock in flood prone areas. The vulnerability and associated flood risk is being reduced for newer construction by adopting new standards (ABCB, 2012), building controls and land use planning, however, the vulnerability associated with existing building stock remains. The vulnerability of existing building stock contributes disproportionally to overall flood risk in many Australian catchments.

The Bushfire and Natural Hazards Collaborative Research Centre (BNHCRC) project entitled {\textquotedblleft}Cost-effective mitigation strategy development for flood prone buildings{\textquotedblright} aims to address this issue and is targeted at assessing mitigation strategies to reduce the vulnerability of existing residential building stock in Australian floodplains. The project addresses the need for an evidence base to inform decision making on the mitigation of the flood risk posed by the most vulnerable Australian houses and complements parallel BNHCRC projects for earthquake and severe wind.

To date, the project within the BNHCRC has developed a building classification schema to categorise Australian residential buildings into a range of typical storey types. Mitigation strategies developed nationally and internationally have been reviewed. Five typical storey types have been selected which represent the most common residential buildings in Australia. A floodproofing matrix has been developed to assess appropriate strategies for the selected storey types. All appropriate strategies have been costed for the selected storey types through the engagement of quantity surveying specialists.

Furthermore, selected building materials/systems have been tested to ascertain their resilience to floodwater exposure. These tests were aimed at addressing knowledge gaps in the areas of strength and durability of building materials during immersion. The results of the tests showed that flooding did not have any significant effect on the pull-out strength of the bond of the ceramic floor and wall tiles to their substrate, nor on the racking strength of the OSB and HDF wall sheet bracing. However, there was a significant reduction (~45\%) in load carrying capacity of the timber joists when tested in the wet condition.

In the following years of the project vulnerability of predominant storey types will be assessed. The information on vulnerability is fundamental to evaluate mitigation strategies and to examine the opportunities for reducing the vulnerability. The research will include cost benefit analysis to find optimal mitigation strategies for selected storey types located within a range of catchment types.

This project is investigating methods for upgrading existing housing stock in floodplains to increase their resilience in future flood events. The project will provide an evidence base to inform decision making by governments and property owners to reduce flood risk. The risk mitigation achieved will decrease human suffering, improve safety and ensure amenity for communities.

}, issn = {333}, author = {Maqsood, T and Martin Wehner and Dale, K} }