@article {bnh-8016, title = {Enhancing resilience of critical road structures: bridges, culvers and floodways under natural hazards {\textendash} final project report}, number = {671}, year = {2021}, month = {05/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

Bridges, culverts and floodways are lifeline road structures and part of road networks, which have a significant role in ensuring resilience of a community before, during and after a natural disaster. Historical data demonstrates that the failure of road structures can have catastrophic consequences on a community affected by disaster due to the impact on evacuation and post disaster recovery.\  The main objective of the project is to understand the vulnerability of critical road structures: bridges, culverts and floodways under natural hazards of flood, bush fire and earthquakes. Once the level of vulnerability is established, the evaluation of importance of the structures for prioritization for hardening is important for decision making by road authorities.

The project funded by the BNH CRC addressed the above gap in knowledge through a comprehensive research program undertaken in collaboration with three research partners and six end user partners. In the first stage of the project, major failure scenarios and the consequences of failure were identified as a precursor for a focused research program on vulnerability modelling and prioritization of road structures under natural hazards. The research conducted included assessment of vulnerability of road bridges under flood, bush fire and earthquakes and floodways and culverts under flood. Further, three approaches were used to identify the consequences of failure of road structures under natural hazards: economic impact on the closure of structures on the community, prioritization of structures using analytical techniques and post disaster social, economic and environmental impacts of failure of road structures.

Major findings of the research include identification of the levels of hazard exposure which could lead to failure of structures and the other parameters affecting failure. Further, methods of modeling road structures under different loading regimes has been developed with case studies of typical structures. New design approaches for building back better have been proposed for floodway structures based on parametric analysis of typical types of floodways.

Major findings of the analysis of bridges under flood loading include (a) the current design process in the design standards for log and object impact are unconservative and rigorous analysis is recommended (b) when the flood velocity is over 4 m/s and the flood level reaches the soffit of the bridge deck, the failure probability of the bridge decks are very high. (c) particle size near the bridge pier foundations have a significant impact on the scour of bridge piers and placement of irregular shaped crushed rock at river-bed level can reduce the scour failure. Research conducted on impact of bush fires on composite structures indicated that the shear failure of the web of the girders is the major failure mode. Under earthquake loading, a major finding is that in the areas where peak ground acceleration is over 0.08g, girder bridges could have a high failure probability and a risk mitigation strategy is essential.

Three different tools are developed for determining the impact of failure of road structures considering economic as well as social, environmental and economic impacts.

A major utilisation outcome of the project is a resilient floodway design guide, published in collaboration with the Institution of Public Works Engineers Australia (Qld) (IPWEAQ). A utilisation project is currently in progress jointly funded by the IPWEAQ and BNH CRC. The guide has been reviewed by the IPWEAQ and is currently being revised by the researchers to enable uptake by local council Engineers. An asset management and vulnerability modeling tool for bridges has been developed for the DoT Victoria (formerly known as VicRoads) where the bridges prone to significant damage are highlighted in a GIS map of the road network.

There are two different models developed to evaluate the consequences of the failure of road structures: first considering economic impact of detour required and a second model capturing post disaster social environmental and economic impact of failure of road structures. The first tool has been incorporated into the vulnerability modeling GIS platform developed for \ the DoT, Victoria.

In addition to the above deliverables in the BNH CRC project, two subsidiary projects were undertaken to understand the effect of cyclonic events on bridge structures and also resilience of timber bridges under natural disasters.

The research team is working with the end users to socialize the vulnerability modeling and decision-making tools developed to enable optimized decision making to enhance resilience of road structures under natural hazards. This is currently being continued with direct funding from the DoT, Victoria.

}, keywords = {Bridge, critical, culvert, enhancing, Floodway, Natural hazards, resilience, road, structure}, issn = {671}, author = {Sujeeva Setunge and Priyan Mendis and Karu Karunasena and Kevin Zhang and Dilanthi Amaratunga and Weena Lokuge and Nilupa Herath and Long Shi and Hessam Mohseni and Huu Tran and Kanishka Atapattu} } @article {bnh-7480, title = {Structural design of floodways under extreme flood loading}, journal = {International Journal of Disaster Resilience in the Built Environment}, volume = {11}, year = {2020}, month = {05/2020}, abstract = {

Purpose

Current methods for floodway design are predominately based on hydrological and hydraulic design principles. The purpose of this paper is to investigate a finite element methods approach for the inclusion of a simplified structural design method into floodway design procedures.

Design/methodology/approach

This research uses a three-dimensional finite element method to investigate numerically the different parameters, geometric configurations and loading combinations which cause floodway vulnerability during extreme flood events. The worst-case loading scenario is then used as the basis for design from which several structural design charts are deduced. These charts enable design bending moments and shear forces to be extracted and the cross-sectional area of steel and concrete to be designed in accordance with the relevant design codes for strength, serviceability and durability.

Findings

It was discovered that the analysed floodway structure is most vulnerable when impacted by a 4-tonne boulder, a 900 mm cut-off wall depth and with no downstream rock protection. Design charts were created, forming a simplified structural design process to strengthen the current hydraulic design approach provided in current floodway design guidelines. This developed procedure is demonstrated through application with an example floodway structural design.

Originality/value

The deduced structural design process will ensure floodway structures have adequate structural resilience, aiding in reduced maintenance and periods of unserviceability in the wake of extreme flood events.

}, keywords = {bridge failure, Flood, floodways, impact load, Infrastructure, resilience}, doi = {https://doi.org/10.1108/IJDRBE-10-2019-0072}, url = {https://www.emerald.com/insight/content/doi/10.1108/IJDRBE-10-2019-0072/full/html?skipTracking=true}, author = {Isaac Greene and Weena Lokuge and Warna Karunasena} } @article {bnh-6868, title = {Vulnerability assessment of bridges subjected to extreme cyclonic events}, journal = {Natural Hazards}, year = {2020}, month = {04/2020}, abstract = {

Over the past few years, Queensland in Australia has suffered from a number of severe tropical cyclones, the most recent one being Marcia, which took place in 2015. Damage bill of Cyclone Marcia exceeded $50 million which included the cost of repairing a number of damaged road structures. Failure of road structures such as bridges isolates communities from accessing essential services and commodities. This necessitated a methodical approach to evaluate the failure of bridges to improve their resilience and provide base knowledge for developing emergency maintenance response. Although there are several methods available to evaluate the vulnerability of bridges, fault tree analysis (FTA) was selected in this study by considering its positive attributes over the other methods. FTA was used to estimate the probabilities of failure of main components (superstructure and substructure) and elements of timber and concrete bridges. Secondary data (level 1 and level 2 bridge inspection reports from Transport Main Roads in Rockhampton) before and after the Cyclone Marcia were used in conjunction with expert advice to construct fault trees for both timber and concrete bridges. Potential failure mechanisms were observed, and the degree of susceptibility of main components of timber and concrete bridges to cyclonic events was evaluated. This research was based on selected bridges under specific cyclone in one region, which is a limitation of the study. Few other case study bridges subjected to cyclonic events can be used to strengthen the understanding of the complete dynamics of the bridge failure under these extreme events.

}, keywords = {bridge failure, cyclone, fault tree analysis, preventative maintenance, Vulnerability}, doi = {https://doi.org/10.1007/s11069-020-03931-y}, url = {https://link.springer.com/article/10.1007/s11069-020-03931-y$\#$citeas}, author = {Thilini Pathiranage and Weena Lokuge} } @article {bnh-5620, title = {Analysis of design standards and applied loads on road structures under extreme events}, number = {480}, year = {2019}, month = {06/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This is the fourth report for the Bushfire and Natural Hazards CRC project B8, entitled {\textquoteleft}Enhancing the Resilience of Critical Road Infrastructure: bridges, culverts and flood-ways under natural hazards{\textquoteright}. The work presented here addresses milestone 3.2.2 {\textquotedblleft}Analysis of design standards completed{\textquotedblright} and 3.2.3 {\textquotedblleft}Draft report 4{\textendash} Loads applied on structures under extreme events (flood, earthquake, fire){\textquotedblright}, which are due on 30 December 2015. Thus, this draft report will be reviewed and refined through the input of the external stakeholders, in particular Queensland Department of Transport and Main Roads (DTMR), VicRoads, RMS (NSW) and the Lockyer Valley Regional Council (LVRC).
The following draft report presents an analysis of relevant design codes in regards to bridges, culverts and flood-ways design considerations under natural hazards (earthquake, flood and bushfire). Although effort has been made to include major design codes, the main focus of the practice code analysis has been Australian codes, major American codes and European codes. Section 5 also discusses the strengthening methods for reinforced concrete members under natural hazards.

}, keywords = {applied loads, engineering, extreme weather, resilience, structure}, issn = {480}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @article {bnh-6126, title = {Enhancing resilience of critical road infrastructure annual report 2018-2019}, number = {519}, year = {2019}, month = {10/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The overarching aim of the proposed second stage of the project is to work closely with key stakeholders to implement the methodologies that have been developed for vulnerability modelling of road structures to priorities vulnerable structures for improvements, to quantify the cost of reconstruction and/or cost of hardening of structures, and to integrate community resilience considerations into the decision-making process.

During the last financial year, the research team has published seven peer-reviewed journal papers (5 Scimago Q1 journal papers), 13 national/international conferences papers and one technical report, while there are eight journal papers under review now.

The major research activities include the generic analysis of bridges in terms of structural analysis, community impact model for decision making on strengthening, floodway inspection methodology, and strengthening options for different hazard types and levels. A floodway inspection and maintenance framework were also developed to guide the future inspection and maintenance of those bridges, especially for those have undergone hazard events.

Four workshops and four meetings were held during the second year of Stage 2 of the project. Two workshops were held at RMIT University to discuss with end users and colleagues regarding the feedback and comments of the project progresses. One workshop was held at the University of Southern Queensland and the Queensland University of Technology, respectively. Feedbacks from these end users have largely benefited the research progress.

Four major utilization activities have been identified and are in progress.

Our next step is to focus on the remaining milestones and engaging with those end users to tailor the research direction and fulfill their urgent research needs. The final project completion report will be also submitted then for the review of BNH CRC.

}, keywords = {Emergency management, engineering, infrastructure resilience}, issn = {519}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Lihai Zhang and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @article {bnh-5435, title = {Enhancing resilience of critical road infrastructure: bridges, culverts and flood-ways under natural hazards Annual Report 2017-2018}, number = {466}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

During stage 1 of the project, disaster risk was understood in terms of the vulnerability of road structures, and the impacts of road failure on local communities. Stage 2 aims to enhance disaster preparedness, inform more effective responses, and ensuring that damaged structures are built back better during the recovery. In Stage 2 of this project, research will continue to apply the methods developed in Stage 1 to examine the vulnerability of categories of road structures for decision making. In addition to the assessment of structural vulnerability, a decision support framework will be developed through collaboration with other research projects of the BNH CRC such as decision making and fire modeling. The overarching aim of the proposed second stage of the project is to work closely with key stakeholders to implement the methodologies that have been developed for vulnerability modelling of road structures to priorities vulnerable structures for improvements, to quantify the cost of reconstruction and/or cost of hardening of structures, and to integrate community resilience considerations into the decisionmaking process. During the first year of Stage 2, several research objectives have been achieved, including hazard mapping for Victoria and Queensland, categorization of road structures, and floodway design process. The related methodologies are introduced below one by one.

}, keywords = {bridges, floodways, infrastructure resilience, Natural hazards}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Lihai Zhang and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @article {bnh-6040, title = {Predicting the probability of failure of timber bridges using fault tree analysis}, journal = {Structure and Infrastructure Engineering}, volume = {15}, year = {2019}, month = {02/2019}, pages = {783-797}, abstract = {

The resilience of a community in an extreme event depends mainly on the robustness of the critical infrastructures. Road bridges are a critical link of the road network, which plays a focal role in Australia{\textquoteright}s economy, prosperity, social well-being and quality of life. Timber bridges are a weaker link of the Australian road network and they often provide critical access to the rural communities. This research uses a number of bridge inspection reports to develop a method to predict the probability of failure of a timber bridge. The inspected condition states of the elements in the timber bridge are used to develop a Markov chain based model and Gamma process model to predict the deterioration of each element. The probability of condition state movement for each element thus calculated were used in fault tree analysis to estimate likelihood of failure of a bridge in a given time period. Although the developed method is based on limited data and it has several limitations, model can be further refined with the availability of more inspection reports. The method developed is demonstrated using an inspection report for a timber bridge, which was not used in the development of the models.

}, keywords = {bridge failure, fault tree analysis, inspection, Markov process, rehabilitation, Timber structures}, doi = {https://doi.org/10.1080/15732479.2019.1569069}, url = {https://www.tandfonline.com/doi/abs/10.1080/15732479.2019.1569069}, author = {Weena Lokuge and Matthew Wilson and Huu Tran and Sujeeva Setunge} } @article {bnh-5216, title = {Failure mechanisms of bridge structures under natural hazards}, year = {2018}, month = {12/2018}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The report captures the major failure modes of bridges under exposure to potential natural hazards in Australia: flood, bushfire and earthquake. Attributes of bridge structures which influence failure and the typical levels of natural hazards experienced in Australia are explored. Case studies on analysis of failure of bridges have been presented which can provide input to vulnerability modelling of the bridge structures.

Analysis of case studies and literature indicated that the most common failure mechanisms of bridge structures under flood is scour, debris loading and damage to approach roads. Failure mechanisms of bridges due to bushfire are significantly affected by the construction material of bridge components. Major mechanisms of failure in reinforced concrete structures is observed to be the spalling of concrete, failure due to reduction in strength and elastic modulus of concrete and yielding of reinforcing steel. In steel bridges, when temperatures rise above 400 degrees Celsius, a rapid reduction in strength of members could lead to failure. Failure mechanisms of the bridges due to earthquake are explored using analytical methods and fragility curves have been developed using finite element modeling of a bridge structure. Deck joints have been observed to be the most vulnerable elements of girder bridges in Australia under earthquake loading. The generic methodology developed will be applied to other structural forms in future.

}, issn = {446}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @article {bnh-6643, title = {Floodway inspection and maintenance framework}, number = {540}, year = {2018}, month = {04/2018}, institution = {Bushfire \& Natural Hazards CRC}, address = {Melbourne}, abstract = {

Bridges, culverts, and floodways are vital road infrastructures for the operation of a road network. Their application may vary based on geographic and demographic features of the territory. Floodways are common in rural road networks as they provide economic and environmental friendly solutions over bridges and culverts. Floodways play a significant role in the economy of a country by connecting regional communities, farmlands and agricultural areas to city centers. For example, 48\% of total agricultural production in Australia in 2006 had been produced from regional council areas, those covering only about 6.9\% of Australia{\textquoteright}s population, 11\% of total Australian land mass and 24\% of roads in length [1]. Floodways are common in most of these rural road networks and, hence, play a vital role to distribute agricultural and farming products to highly populated city centers. Therefore, healthy operational levels of floodways are of paramount importance to maintain the continuous supply of essential commodities and the economic balance of Australia.

Floodways are different from bridges and culverts in the design and operational aspects. By definition, floodways are sections of roads which have been designed to be overtopped by floodwater during relatively low average recurrence interval (ARI) floods and are expected to return to fully serviceable level after the flood water recedes [2]. Although, floodways are designed to withstand at low flood levels, extreme natural disasters can damage these vital road infrastructures as evident from the 2011 and 2013 Queensland flood events. 58\% of floodway structures in the Lockyer Valley Regional Council (LVRC) area in Queensland, Australia, were damaged during the 2013 Queensland flood event leading to operational failures in rural road networks. Floodway damage leads to isolating regional communities and hindering the supply of agricultural products to other regions. In a post-disaster period, the long-term impacts on the community and the economy of the country depend on the speed of reestablishing the fully operational level of those floodways.

}, keywords = {Flood, Floodway, framework, maintenance}, issn = {540}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Priyan Mendis and Tuan Ngo and Nilupa Herath and Karu Karunasena and Weena Lokuge and Dilanthi Amaratunga} } @article {bnh-6057, title = {Quantitative assessment of flood discharges and floodway failures through cross-cultivation of advancement in knowledge and traditional practices}, journal = {International journal of disaster resilience in the built environment}, volume = {9}, year = {2018}, month = {11/2018}, pages = { 435-456}, abstract = {

Purpose

The 2011 and 2013 Queensland, Australia flood events caused massive infrastructure damage for low-level stream crossings such as floodways and culverts in regional Queensland. Failures of newly built floodways during the 2013 Queensland flood event in the Lockyer Valley Regional Council area raised significant concerns with respect to floodway design practices adopted in Australia and attracted significant research interest to enhance the resilience of floodways. Review of existing floodway design guidelines indicates that floodway design process is closely related to hydraulic and hydrological aspects. However, conducting a hydrological analysis is a challenging in rural areas, mainly owing to information scarcity. Floodways in rural areas often require a simple and economical solution contrast to more detailed hydrological analysis approaches adopted in urbanised areas. This paper aims to identify and apply the rational method to estimate maximum flood discharges at selected floodway locations in the Lockyer Valley Regional Council area. The paper further attempts to provide the first insight of flood characteristics during the 2011 and 2013 Queensland flood events at three catchment outputs across the selected case study area. It also highlights modern day challenges for practising engineers and researchers when estimating flood characteristics in rural areas. The paper shows that cross-cultivation of advancement in engineering practices and traditional approaches can promote quantitative approaches when assessing floodway damage in regional areas.

Design/Methodology/Approach

The research identifies limitations when assessing flood impact in rural regions in collaboration with experience from industry partners and authors themselves. The authors developed a framework to overcome those limitations arising from information scarcity to minimise the trial and error design approaches utilised in the current design practices for floodways.

Findings

This paper developed a simple and effective hydrological method with minimum inputs. It also provides an example on collating available but scattered resources and traditional method to quantitatively assess flood discharges of a rural catchment in Australia. Flood discharges at three catchment outlets along the Left-Hand Branch Road in the Lockyer Valley Region during both 2011 and 2013 Queensland flood events are estimated for the first time. The findings highlight the impact of flood discharges and flooded period on floodway failures.

Research implications/limitations

The current research is based on a selected case study area in Australia. However, similar challenges are expected all across the world, due to the scarcity of rainfall and flood measurement gauges.

Practical implications

Floodway designers can apply similar framework to estimate the flood discharges instead of current practice of trial and error process. This will provide more scientific and reliable estimation and assessment process.

Social implications

One of the social impacts identified in the broader research is the community outrages and disagreement between floodway design engineers and the community. Following the developed framework in the manuscript, design engineers will be able to justify their assumptions and design work.

Originality/value

The paper presents a novel framework on collating different and scattered information towards estimating flood discharges in rural areas. The manuscript presents the first insights on estimated flood discharges in the selected case study area during the 2011 and 2013 Queensland flood events. This will enable further research to be performed in a quantitative manner rather than the present approach of qualitative manner.

}, keywords = {Damaged assets, Flood discharge, Flooding, rainfall}, doi = {https://doi.org/10.1108/IJDRBE-09-2017-0051}, url = {https://www.emerald.com/insight/content/doi/10.1108/IJDRBE-09-2017-0051/full/html}, author = {Buddhi Wahalathantri and Weena Lokuge and Karu Karunasena and Sujeeva Setunge} } @article {bnh-4386, title = {Enhancing the resilience of critical road infrastructure: annual project report 2016-17}, number = {311}, year = {2017}, month = {09/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

In the funded first stage, the project aimed to develop vulnerability models for critical road structures: bridges, culverts and floodways under natural hazards of flood, bush fire and earthquakes. In the second stage of the project, optimized maintenance and strengthening regimes required to enhance resilience of critical road structures will be identified and a decision making tool will be developed.

During the past year, the research focused on analysis of the case studies available from end user partners and development of the methodology for vulnerability modeling of bridges and floodways under natural hazards of flood, earthquake and bushfires. Three case studies were analysed to further establish the methodology and a reliability based approach was established to account for the variability of the frequency and the intensity of disasters. A field study was undertaken to understand the economic impact due to failure of road structures during the 2011 and 2013 floods in the Lockyer Valley region in Queensland.

Three major workshops and a number of informal meetings were held during the past year with excellent participation of end users and researchers. A workshop has also been organized on 24 July 2017 to plan the work program for the second stage of the project and develop the utilization plan.

Six Ph.D candidates are progressing their research funded by APA, RMIT and IPRS scholarships. Three of the students secured CRC top up scholarships as well. One Master by research student completed in 2016 and one PhD will complete in 2017.\  Each of the four strands of the project has recruited a researcher to engage in the project and also utilized final year undergraduate projects to contribute to the research project.

Major outcomes during the past year can be summarized as development of the vulnerability modeling methodology for critical road structures exposed to extreme events and demonstration of the methodology using four case studies. This work has been published in number of journal papers and conferences and posters published in highly regarded journals and conferences. Members of the team also has been successful in winning awards for their work.\ 

}, issn = {311}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @article {bnh-5191, title = {Predicting the failure of timber bridges by using current inspection reports}, journal = {Engineering for Public Works}, volume = {7}, year = {2017}, month = {11/2017}, pages = {85-89}, chapter = {85}, abstract = {

There is a large timber bridge stock in service within Australia and currently over 300 timber bridges on Queensland state controlled roads. Majority of these timber bridges are in the latter half of their service life and require constant maintenance as the timber components deteriorate over time. Detailed level 2 inspections are performed as part of the bridge management systems used by road authorities. This paper discusses a simple method to use an inspection report to predict the chance of the failure of the bridge in a given number of years. Although the Markov process adopted in this research was based on inspection reports for several timber bridges for three time periods, it can further be refined using a data base of inspections for many time periods and environmental conditions. The proposed method is demonstrated using an inspection report for a hypothetical timber bridge.

}, url = {https://issuu.com/ipweaqld/docs/epw_september_2017}, author = {Weena Lokuge and Matthew Wilson and Huu Tran and Sujeeva Setunge} } @article {bnh-3116, title = {Enhancing resilience of critical road infrastructure: bridges, culverts and flood-ways under natural hazards: annual project report 2015-2016}, number = {236}, year = {2016}, month = {10/2016}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

In the funded first stage, the project aims to develop vulnerability models for critical road structures: bridges, culverts and floodways under natural hazards of flood, bush fire and earthquakes. In the second stage of the project, optimised maintenance and strengthening regimes required to enhance resilience of critical road structures will be identified and a decision making tool will be developed.

During the past year, the research focused on analysis of the case studies available from end user partners and development of the methodology for vulnerability modeling of bridges and floodways under natural hazards of flood, earthquake and bushfires. Three case studies were analysed to further establish the methodology and a reliability based approach was established to account for the variability of the frequency and the intensity of disasters. A field study was undertaken to understand the economic impact due to failure of road structures during the 2011 and 2013 floods in the Lockyer Valley region in Queensland.

Four workshops and a number of informal meetings were held during the project with excellent participation of end users and researchers. A mini-symposium held in July 2015 at RMIT University brought researchers, end users and wider stakeholders from across Australia and the UK. A stakeholder workshop held on 17 March 2016 identified end user needs and a utilisation plan was developed based on the outcomes. During the workshops, case study data were identified and the methodology for vulnerability modeling was refined. Future data needs were communicated to the end users.

Five Ph.D candidates commenced work with the research team on APA and IPRS scholarships. Three of the students secured Bushfire and Natural Hazards CRC{\textquoteright}s top up scholarships as well. One Masters by research student and one PhD will complete in 2016 and 2017 respectively.\  Each of the four strands of the project has recruited a researcher to engage in the project and also utilised final year undergraduate projects to contribute to the research project.

Major outcomes during the past two years can be summarised as development of the vulnerability modeling methodology for critical road structures exposed to extreme events and demonstration of the methodology using four case studies. This work has been published in 26 Publications including 9 journal papers, 12 refereed conference papers and 5 reports. In addition, the project research team has been invited to a total number of 12 highly regarded conferences roundtables, workshops and forums to present keynote speeches, chair and co-chair panels and facilitate workshops.

}, issn = {236}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @article {bnh-5073, title = {Fault tree analysis method for deterioration of timber bridges using an Australian case study}, journal = {Built Environment Project and Asset Management}, volume = {6}, year = {2016}, abstract = {
Purpose
{\textendash} Deterioration of timber bridges can often be related to a number of deficiencies in the bridge elements, connectors and/or as a result of been in aggressive environments which they are exposed to. The maintenance cost of timber bridges is affected significantly by a number of deterioration mechanisms which require a systematic approach for diagnosis and treatment. Evaluating the risk of failure of these bridges is of importance in bridge performance assessment and decision making to optimize rehabilitation options. The paper aims to discuss these issues.

Design/methodology/approach
{\textendash} This paper identifies common causes for timber bridge deterioration and demonstrates an integrated approach based on fault tree analysis to obtain qualitative or quantitative estimation of the risk of failure of timber bridge sub-systems. Level 2 inspection report for a timber bridge in Queensland, Australia has been utilized as a case study in this research to identify the failure modes of the bridge.

Findings
{\textendash} A diagnostic tool for timber bridge deterioration will benefit asset inspectors, managers, and engineers to identify the type, size and the distress mechanisms in order to recognize the proper corrective measures either to prevent or to reduce further deterioration. Timber bridge maintenance is a major issue in Queensland, Australia. If a decision support tool can be developed, it will benefit road authorities and local councils.

Originality/value
{\textendash} Timber bridge maintenance is a major issue in Queensland, Australia. If a decision support tool can be developed as initiated in this research paper it will benefit road authorities and local councils.
}, doi = {https://doi.org/10.1108/BEPAM-01-2016-0001}, url = {https://www.emeraldinsight.com/doi/pdfplus/10.1108/BEPAM-01-2016-0001}, author = {Weena Lokuge and Nirdosha Gamage and Sujeeva Setunge} } @article {bnh-2351, title = {Enhancing resilience of critical road infrastructure: bridges, culverts and floodways under natural hazards: Annual project report 2014-2015}, number = {144}, year = {2015}, month = {02/11/2015}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The project aims to develop vulnerability models for critical road structures: bridges, culverts and floodways under natural hazards of flood, bushfire and earthquakes. In the second stage of the project, optimized maintenance and strengthening regimes required to enhance resilience of critical road structures will be identified and a decision making tool will be developed.

During the past year, the research focused on analysis of the case studies available from end user partners and development of the methodology for vulnerability modeling of bridges and floodways under natural hazards of flood, earthquake and bushfires. A field study was undertaken to examine the community impact due to failure of road structures during the 2011 and 2013 floods in the Lockyer Valley region in Queensland. Researchers spent one week conducting semi-structured interviews of the community and identified the major community impacts due to failure of road structures.

Four workshops and a number of informal meetings were held during the year with excellent participation of end users researchers. During the workshops, case study data were identified and the methodology for vulnerability modeling was refined. Future data needs were communicated to the end users.

Two new Ph.D candidates commenced work with the research team on APA scholarships and two more will commence in July 2015. Each of the four strands of the project has recruited a researcher to engage in the project.

Major outcomes during the past year can be summarized as development of the vulnerability modeling methodology for critical road structures exposed to extreme events and demonstration of the methodology using four case studies. This work has been published in three peer reviewed conference papers and submitted as four journal papers. One journal paper has been accepted for publication. In addition, work was presented as invited papers at three industry events.

}, issn = {144}, author = {Sujeeva Setunge and Chun Qing Li and Darryn McEvoy and Kevin Zhang and Jane Mullett and Hessam Mohseni and Priyan Mendis and Tuan Ngo and Nilupa Herath and Karu Karunasena and Weena Lokuge and Buddhi Wahalathantri and Dilanthi Amaratunga} } @conference {bnh-2082, title = {Framework to inspect floodways towards estimating damage - peer viewed}, booktitle = {Adelaide Conference 2015}, year = {2015}, address = {Adelaide, Australia}, abstract = {

Research proceedings from the Bushfire and Natural Hazards CRC \& AFAC Conference in Adelaide, 1-3 September 2015.\ 

}, author = {Buddhi Wahalathantri and Weena Lokuge and Karu Karunasena and Sujeeva Setunge} } @article {bnh-1950, title = {Vulnerability of Floodways under Extreme Flood Events}, journal = {Natural Hazards Review}, volume = {17}, year = {2015}, month = {13/07/2015}, abstract = {

Floodways are commonly used in rural road networks due to the economic and environmental benefits offered as a low-cost and practical road crossing in flood-prone areas. They are designed with provision for submergence so that water flows over with minimum impediment to flow, at a probability given design flood. The floodway design process is traditionally governed by hydraulic aspects rather than structural aspects. Hydrological condition, availability of material, and familiarity of construction techniques are significant when selecting the floodway type. Nevertheless, extreme conditions can cause significant damage to floodways, as was evident from the 2011 and 2013 Queensland flood events, during which 58\% of floodways in the Lockyer Valley Regional Council (LVRC) area in Queensland, Australia, which is the case study area of this paper, were damaged, causing huge economic lost at council and national level. This created a new track in research and development activities to assess vulnerability and to find methods for improving the resilience of floodways during extreme flood events. In line with this, the present study evaluates local design guidelines and damaged floodways to assess failure modes and severity of damage using a damage index (DI) method.

}, keywords = {Damage index, Damage severity, Design guidelines, Flood, Floodway, Vulnerability}, issn = {1527-6996}, doi = {10.1061/(ASCE)NH.1527-6996.0000194}, url = {http://ascelibrary.org/doi/abs/10.1061/(ASCE)NH.1527-6996.0000194}, author = {Buddhi Wahalathantri and Weena Lokuge and Karu Karunasena and Sujeeva Setunge} }