@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} } @mastersthesis {bnh-7361, title = {Damage modelling of reinforced concrete bridge piers under flood and log impact}, volume = {Doctor of Philosophy (PhD)}, year = {2019}, month = {11/2019}, school = {RMIT University}, address = {Melbourne}, abstract = {

Australia has suffered from the loss of life and extreme damage to infrastructure from natural hazards such as bushfire, flood etc. Floods are Australia{\textquestiondown}s costliest disasters on bridges, one of the most important components of highway and railway transportation network. Therefore, safety and serviceability of bridges have always been a great concern to the practice and profession of civil engineering. The resilience of critical infrastructures such as roads and bridges is vital in evacuation support activities for during, before and after disaster response and recovery. In addition, bridges have a significant impact on the resilience of road infrastructure and the damage to bridges could significantly increase the vulnerability of the community served by the transportation infrastructure. Therefore, understanding the factors which affect the resilience of bridge structures, is extremely important to ensure the design specifications, as well as maintenance regimes for bridge structures. Furthermore, considering the resilience and vulnerability of structures is vital during, before and after disasters. Roads Corporation of Victoria (VicRoads) has identified that older structures consisting of U-slab decks are vulnerable to flood loading. The proposed project will focus on understanding damages to U-slab bridges exposed to flood loading.\ \ \ 
The vulnerable element of the case study U-slab bridges has been identified using a simplified analysis using Space-Gass. This analysis indicated that the superstructure of a U slab structure is quite robust under flood loading and slender piers can be vulnerable. Water flow pressure on the piers has been studied using Computational Fluid Dynamics (CDF) methodology to examine the pressure distribution on piers with two different cross-sectional shapes. This work has demonstrated that the pressure distribution on a bridge pier under flood loading can be simulated using a uniformly distributed load. Further, it is noted that the magnitude of the flood-induced force is significantly affected by the geometry of the pier cross-section.
Considering the concrete plasticity damage (CPD) modelling, nonlinear analysis has been conducted to evaluate the damage behaviour of the piers, and a simple damage index based on energy absorbed, which can be derived from a standard finite element modelling output, has been introduced. Based on that different damage levels of a bridge pier under flood loading damage indices have been derived.
Based on the review of practice and the literature review the log or moving object impact is likely to be occurring during flood loading. Therefore, a comprehensive investigation has been conducted to understand the structural response of a moving object impact, i.e., log impact. Using a validated model, the general relationship between different aspects of the structural response has been studied. Moreover, the bridge damage response during log impact has been studied, and the numerical results have been compared to provisions of different design standards. This study has concluded that the current provisions of design standards on the log or any moving object impact on bridges under flood loading could be unconservative and will require a systematic study considering the varying mass of impacts and the geometry of bridge piers.
}, keywords = {Bridge, engineering, Flood, modelling}, url = {https://researchrepository.rmit.edu.au/discovery/fulldisplay?docid=alma9921892810901341\&context=L\&vid=61RMIT_INST:ResearchRepository\&lang=en\&search_scope=ResearchETD\&adaptor=Local\%20Search\%20Engine\&tab=Research\&query=any,contains,Maryam\%20Nasim\&offset=0}, author = {Maryam Nasim} } @article {bnh-6042, title = {Dynamic Behavior of Indonesian Bridges using Interferometric Radar Technology}, journal = {Electronic Journal of Structural Engineering}, volume = {18}, year = {2018}, month = {2018}, pages = {23-29}, abstract = {

Structural deterioration of critical transport infrastructures (e.g., bridges) represents trillion dollars of transportation budget. Inspection and monitoring structural deterioration of bridge structures require an innovative method for an improved quality and accuracy of measurements. This paper presents and discusses the capabilities of the recent advanced interferomertic radar technique (IBIS-S) for remote monitoring structural vibations of bridges (e.g., displacement and natural frequency). Three case studies bridges in Indonesia were selected for field measurements. The research outcomes demonstrate the potential use of interferometric radar technology as an efficient way for structural health assessment and monitoring of bridges under operational condition.

}, keywords = {Bridge, displacement, Dynamic behavior, IBIS-S, Natural frequency}, url = {http://www.ejse.org/Archives/Fulltext/2018-1\%20Sp/2018-1-3.pdf}, author = {Maizuar Maizuar and Elisa Lumantarna and Sofi Massoud and Oktavianus Yusak and Lihai Zhang and Colin Duffield and Priyan Mendis} } @article {bnh-6044, title = {Health Assessment of a Pedestrian Bridge Deck using Ground Penetrating Radar}, journal = {Electronic Journal of Structural Engineering}, volume = {18}, year = {2018}, month = {2018}, pages = {30-37}, abstract = {

Scanning concrete structures using ground penetrating radars (GPR) continues to be one of the most efficient methods for defect (i.e. crack, void and delamination) detection within concrete structures as well as detection of reinforcing bars damage due to corrosion. The aim of this study was to assess the structural health of a 45-year old pedestrian bridge deck. To achieve this, a number of experiments using a GPR system were conducted on a strong concrete floor with known construction drawings to detect cover depth and rebar orientations. After validating the GPR results through the experiments, the GPR system was used for nondestructive assessment of the pedestrian bridge deck. From the scanned results, the location and orientation of the reinforcing bar were established. In addition, the diameters of the bars was estimated by measuring the thickness of the hyperbola curves in the B-scans. The scanned output shows no signs of corrosion of reinforcement or damage of concrete in the form of delamination or cracking.

}, keywords = {Bridge, Ground Penetrating Radars, Non-Destructive Techniques, Structural Heath Assessment}, url = {https://www.researchgate.net/profile/Colin_Duffield/publication/326734315_Health_Assessment_of_a_Pedestrian_Bridge_Deck_using_Ground_Penetrating_Radar/links/5b61464baca272a2d678d7d9/Health-Assessment-of-a-Pedestrian-Bridge-Deck-using-Ground-Penetrating-Ra}, author = {Saeed Miramini and Massoud Sofi and Ahmed Aseem and Ali Baluwala and Lihai Zhang and Priyan Mendis and Colin Duffield} } @article {bnh-4668, title = {Displacement Based Design of Bridge Abutments}, journal = {Australian Earthquake Engineering Society}, year = {2016}, month = {11/2016}, abstract = {

The present study deals with the drift and displacement capacities of reinforced concrete (RC) bridge abutments subjected to seismic excitations. Two dimensional (2D) finite element (FE) analyses have been conducted to investigate the behavior of the bridge abutment taking into account dynamic actions of the backfill in seismic conditions. The capability of scaled down bridge abutment models is also investigated in order to replicate the dynamic behavior of prototype bridge abutments. The analyses have taken into account interactions between the abutment and the backfill, which can significantly affect the seismically induced displacement behavior of the bridge abutments. It was observed that scaled down bridge abutment models could effectively replicate the seismic behavior of prototype bridge abutments. The stiffness of the bridge abutment degrades significantly with increasing intensity of ground motion. The location of the point of rotation of the bridge abutment is almost constant irrespective of the height of the stem wall. Drift and displacement behavior of the bridge abutment is highly controlled by the thickness of the stem wall.

}, keywords = {abutment, Bridge, design, performance, seismic, similitude.}, url = {https://www.aees.org.au/wp-content/uploads/2018/06/337-Tiwari-et-al.pdf}, author = {Rohit Tiwari and Nelson Lam and Elisa Lumantarna} }