@conference {bnh-8345, title = {Geotechnical seismic isolation system based on rubber-soil mixtures: analytical modelling, experimental testing and field measurement}, booktitle = {20th International Conference on Soil Mechanics and Geotechnical Engineering}, year = {2022}, month = {06/2022}, address = {Sydney}, abstract = {

The innovative concept of geotechnical seismic isolation (GSI) with the use of a continuous layer of low-modulus
rubber-soil mixtures (RSM) surrounding the foundation of the structure has attracted considerable research interest globally in the
past decade. This paper presents a summary of the recent works completed by the authors. This includes an equivalent-linear lumped-parameter analytical model for explaining the isolation mechanism of the GSI system. On the other hand, the effectiveness of the isolation system has been validated by geotechnical centrifuge modelling. Its dynamic soil-structure interaction behaviour has also
been demonstrated by using the Euroeseistest-EuroProteas model structure (http://euroseisdb.civil.auth.gr). It has been confirmed
that the controlled stiffness and damping of the GSI-RSM foundation layer can reduce the rocking stiffness, thereby enhances the
seismic isolation capability, whilst without having large permanent deformations due to the higher elasticity of the RSM material.
Finally, a series of shaking table tests have also been conducted to examine the effectiveness of GSI-RSM system on isolating
electrical transformers. Generally, it was found in these studies that a 30\% to 60\% reduction of structural demand can be achieved.

}, keywords = {augmented rocking, geotechnical seismic isolation, rubber-soil mixtures, soil-structure interaction, waste tyre}, url = {https://www.researchgate.net/profile/Dimitris-Pitilakis/publication/361275994_20ICSMGE-Full-Paper-final/links/62a840f06886635d5cd89d75/20ICSMGE-Full-Paper-final.pdf}, author = {Hing-Ho Tsang and Kyriazis Pitilakis and Sheng Li and Wen-Yi Hung} } @article {bnh-7961, title = {Generalized Loading Protocols for Experimentally Simulating Multidirectional Earthquake Actions on Building Columns in Regions of Low-to-Moderate Seismicity }, journal = {Journal of Structural Engineering}, volume = {147}, year = {2021}, month = {04/2021}, abstract = {

This study aimed to quantitatively develop realistic quasi-static loading protocols for simulating bidirectional cyclic actions and axial load variation on building columns in a way that is representative of an actual response during earthquake ground excitation. A case-study building was subjected to a suite of 15 ground motions that were scaled to design basis earthquake (DBE) and maximum considered earthquake (MCE) levels of a typical region of low-to-moderate seismicity. The results showed that the displacement path of a building column under earthquake actions is generally in the form of elliptical loops of various orientations due to the phase difference in the sinusoidal displacements in the two orthogonal axes of the column. Accordingly, this work proposes a bidirectional lateral loading protocol that simplifies and generalizes the displacement path of the column in the form of elliptical loops of four different orientations. Similarly, the patterns of axial load variation in columns were also studied in detail, which led to the development of separate axial load variation protocols for external and internal columns of a building, which can be applied in tandem with the bidirectional lateral loading protocol. The paper concludes with a brief overview of the results of two reinforced concrete (RC) column specimens, which were experimentally tested using the proposed bidirectional loading protocol.

}, keywords = {earthquakes, engineering, reinforced concrete structures}, doi = {https://doi.org/10.1061/(ASCE)ST.1943-541X.0003056}, url = {https://ascelibrary.org/doi/abs/10.1061/\%28ASCE\%29ST.1943-541X.0003056}, author = {Saim Raza and Hing-Ho Tsang and Scott Menegon and John Wilson} } @article {bnh-7137, title = {An Adaptive Ground Motion Prediction Equation for Use in Low-to-Moderate Seismicity Regions}, journal = {Journal of Earthquake Engineering}, year = {2020}, month = {07/2020}, pages = {1-23}, abstract = {

In regions of low-to-moderate seismicity where representative strong motion data is lacking, the modelling of seismic hazard relies on the use of seismological models. This paper presents a set of expressions that can be used as ground motion prediction equations that have been transformed from seismological models which resolve the generation of seismic waves into several components. The feature of this presented set of expressions is that it can be adapted to represent earthquake ground motion behaviour that is defined by a diversity of seismological models. The motivation behind the development of the presented adaptive predictive relationship which is known as the\ Component Attenuation Model\ (CAM) was to fast track, and make transparent, the transformation from seismological models to predictions of response spectral values for engineering applications. Thus,\ CAM\ can be used to waive away the need of executing any software for undertaking stochastic simulations nor time-history analyses for calculation of the response spectral ordinates. An important and original, the feature of\ CAM\ is incorporating the shear wave velocity profile of the bedrock and the associated upper-crustal modification into the model. This article presenting\ CAM\ is essentially a contribution to engineering as opposed to seismology. The potential benefits derived from the fast-tracking can be considerable given that the transformation is seldom a one-off process and would need to be repeated for any given targeted area, in view of uncertainties surrounding seismological conditions of the earth crust around the globe.

}, keywords = {attenuation parameter, Component attenuation model, ground motion prediction equations, upper-crustal modification}, doi = {https://doi.org/10.1080/13632469.2020.1784810}, url = {https://www.tandfonline.com/doi/abs/10.1080/13632469.2020.1784810}, author = {Yuxiang Tang and Nelson Lam and Hing-Ho Tsang and Elisa Lumantarna} } @article {bnh-7017, title = {Axial Load Variation of Columns in Symmetrical RC Buildings Subject to Bidirectional Lateral Actions in Regions of Low to Moderate Seismicity}, journal = {Journal of Earthquake Engineering}, year = {2020}, month = {06/2020}, pages = {1-29}, abstract = {

Columns in building frame systems are subjected to the combined action of bidirectional horizontal loading and axial load variation during an earthquake. Whilst the behaviour of RC columns under unidirectional and bidirectional lateral loading with constant axial load is understood well, the behaviour under bidirectional lateral loading with axial load variation is rarely studied, especially for limited ductile RC columns prevalent in regions of low to moderate seismicity. This paper begins with a numerical study that aims to obtain the generalised patterns and range of axial load variation in RC building columns. To this end, a case study building is subjected to a suite of 15 ground motions, representative of low to moderate seismic regions, in OpenSees. This is followed by an experimental study in which limited ductile high-strength RC columns are tested under bidirectional lateral loading and two different axial load variation protocols, namely synchronous and nonsynchronous variable axial loading protocols. The results of the numerical study demonstrated that axial load variation of the columns in an RC building is primarily dependent on the response spectral acceleration corresponding to the fundamental period of the structure in the two orthogonal horizontal directions and/or the vertical direction. The results of the experimental testing showed that nonsynchronous axial loading (compared to constant and synchronous axial loading) results in the lowest collapse drift capacity and energy dissipation of the RC columns.

}, keywords = {Axial load variation, bidirectional loading, drift capacity, earthquake, RC columns}, doi = {https://doi.org/10.1080/13632469.2020.1772151}, url = {https://www.tandfonline.com/doi/abs/10.1080/13632469.2020.1772151?journalCode=ueqe20}, author = {Saim Raza and Scott Menegon and Hing-Ho Tsang and John Wilson} } @article {bnh-7464, title = {Collapse probability of soft-storey building in Australia and implications for risk-based seismic design}, journal = {Australian Journal of Structural Engineering}, year = {2020}, month = {10/2020}, pages = {1-13}, abstract = {

Collapse prevention is the primary objective of earthquake-resistant design of structures; hence, the probability of collapse should be taken as a crucial performance indicator for risk-based design of new structures or assessment of existing structures. One major challenge in collapse risk assessment is to reliably model the non-linear structural response behaviour. This study features the rocking response behaviour of precast reinforced concrete (RC) columns based on results from previous field testing on parts of a real building and supplemented with a study of their rocking behaviours through a series of shake-table tests. The effects of bidirectional earthquake actions on failure drift capacity of columns have also been incorporated, such that realistic estimates of displacement capacity were made for constructing collapse fragility functions, which were then combined with the ground motion recurrence relationships of Melbourne, Australia for the computation of collapse probability. A suite of typical soft-storey buildings was adopted, with considerations given to a diversity of site conditions. Deaggregation of the results reveals the range of return periods that controls the collapse risk, which could have important implications for the choice of earthquake scenarios for seismic analysis and design in regions of lower seismicity.

}, keywords = {Collapse Probability, drift capacity, Return Period, Risk-based Seismic Design, soft-storey building}, doi = {https://doi.org/10.1080/13287982.2020.1835157}, url = {https://www.tandfonline.com/doi/abs/10.1080/13287982.2020.1835157}, author = {Hing-Ho Tsang and John Wilson and Emad F Gad} } @article {bnh-7574, title = {A Computational Tool for Ground-Motion Simulations Incorporating Regional Crustal Conditions}, journal = {Seismological Research Letters}, year = {2020}, month = {11/2020}, abstract = {

This article introduces a computational tool, namely ground-motion simulation system (GMSS), for generating synthetic accelerograms based on stochastic simulations. The distinctive feature of GMSS is that it has two independently developed upper-crustal models (expressed in the form of shear-wave velocity profiles), which have been built into the program for deriving the frequency-dependent crustal factors, and one of these models was originally developed by the authors. GMSS also has provisions to allow the user to specify their own preferred crustal profile. Sufficient details of both crustal models (forming part of the seismological model) and the accelerogram simulation methodology are presented herein in one article, to allow any person who has programming skills (on a user-friendly platform such as MATLAB, see\ Data and Resources), to develop their computational tools to implement any further innovations in crustal modeling for direct engineering applications. Crustal properties deep into bedrock can only be accounted for implicitly by conventional ground-motion prediction equation (GMPE) as much depends on the region where the ground motion was recorded. This limitation of existing GMPEs poses a challenge to engineering in regions that are not well represented by any strong-motion database. Toward the end of this article, readers are enlightened with the potential transdisciplinary utility of using GMSS, to facilitate the retrieval and scaling of accelerograms sourced from a database of real earthquake records through the construction of a conditional mean spectrum.

}, keywords = {Computational tool, modelling, seismic}, doi = {https://doi.org/10.1785/0220200222}, url = {https://pubs.geoscienceworld.org/ssa/srl/article-abstract/doi/10.1785/0220200222/592863/A-Computational-Tool-for-Ground-Motion-Simulations?redirectedFrom=fulltext}, author = {Yuxiang Tang and Nelson Lam and Hing-Ho Tsang} } @article {bnh-6781, title = {Final report on vulnerability of as-built and retrofitted LDRC buildings}, number = {551}, year = {2020}, month = {03/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Previous Bushfire and Natural Hazard CRC (BNH CRC) reports have presented the fragility curves for reinforced concrete buildings that are supported by reinforced concrete walls and moment resisting frames, and the fragility curves for this type of buildings with four retrofitting options. This study presents the vulnerability curves for these buildings presented in terms of damage factor, which is the ratio of the repair cost to the replacement cost for the buildings. This report contributes to the project {\textquotedblleft}Cost-effective mitigation strategy development for building related earthquake risk{\textquotedblright} which is aimed to develop knowledge to facilitate evidence-based informed decision making in relation to the need for seismic retrofitting, revision of codified design requirement, and insurance policy.

}, keywords = {as-built, buildings, retrofit, Vulnerability}, issn = {551}, author = {Elisa Lumantarna and Nelson Lam and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-7687, title = {Performance of geotechnical seismic isolation system using rubber-soil mixtures in centrifuge testing}, journal = {Earthquake Engineering and Structural Dynamics}, year = {2020}, month = {11/2020}, abstract = {

Geotechnical seismic isolation (GSI) system involves the dynamic interaction between structure and low-modulus foundation material, such as rubber-soil mixtures (RSM). Whilst numerical studies have been carried out to demonstrate the potential benefits of GSI-RSM system, experimental research is indispensable for confirming its isolation mechanism and effectiveness in reducing structural demand. In this regard, centrifuge modelling with an earthquake shaker under an acceleration field of 50\ g adopted in this study can mimic the actual nonlinear dynamic response characteristics of RSM and subsoil in a coupled soil-foundation-structure system. This is the first time the performance of GSI-RSM system was examined in a geotechnical centrifuge. It was found that an average of 40-50\% reduction of structural demand can be achieved. The increase in both the horizontal and rotation responses of the foundation was also evidenced. The unique augmented rocking mechanism with reversible foundation rotation was highlighted.

}, keywords = {augmented rocking mechanism, centrifuge, geotechnical seismic isolation, rubber-soil mixtures, waste tyre}, doi = {https://doi.org/10.1002/eqe.3398}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/eqe.3398}, author = {Hing-Ho Tsang and Duc-Phu Tran and Wen-Yi Hung and Kyriazis Pitilakis and Emad F Gad} } @article {bnh-5433, title = {Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk Annual Report 2017-2018}, number = {464}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {
This project arose out of the on-going research efforts by the group involving\ structural engineering academics at the Universities of Adelaide, Melbourne and\ Swinburne with Geoscience Australia experts all working towards seismic risk\ reduction in Australia. Most of the research team are actively involved in the\ revision to the Australian Earthquake Loads standard (AS1170.4) as well as being\ members of the Australian Earthquake Engineering Society which is a Technical\ Society of Engineers Australia. The devastating impact of the 2010{\textendash}11\ earthquakes in the Christchurch region on the New Zealand economy and\ society has further motivated this group to contribute to this CRC{\textquoteright}s aims of risk\ reduction for all natural hazards in Australia.\ This project addresses the need for an evidence base to inform decision making\ on the mitigation of the risk posed by the most vulnerable Australian buildings\ subject to earthquakes. While the focus of this project is on buildings, many of\ the project outputs will also be relevant for other Australian infrastructure such as\ bridges, roads and ports, while at the\ same time complementing other {\textquoteleft}Natural\ Hazards{\textquoteright} CRC project proposals for severe wind and flood.
}, keywords = {cost-mitigation, earthquake}, author = {Michael Griffith and Hossein Derakhshan and Elisa Lumantarna and Hing-Ho Tsang and John Wilson and Nelson Lam and Mark Edwards and Martin Wehner} } @article {bnh-6011, title = {Design procedure for seismic retrofit of RC beam-column joint using single diagonal haunch}, journal = {Structural Engineering and Mechanics}, volume = {71}, year = {2019}, month = {08/2019}, pages = {341-350}, abstract = {

Exterior beam-column joint is typically the weakest link in a limited-ductile reinforced concrete (RC) frame structure. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for reducing the seismic demand at the joint. Previous research globally has focused on implementing double haunches, while the use of single haunch element as a less-invasive and more architecturally favorable retrofit option has not been investigated. In this paper, the key formulations and a design procedure for the single haunch system for retrofitting RC exterior beam-column joint are developed. An application of the proposed design procedure is then illustrated through a case study.

}, keywords = {limited-ductile; RC frame; exterior beam-column joint; seismic retrofit; single diagonal haunch}, doi = {https://doi.org/10.12989/sem.2019.71.4.341}, url = {http://koreascience.or.kr/article/JAKO201924750736475.page}, author = {Zabihi, Alireza and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-6043, title = {Framework for seismic vulnerability assessment of reinforced concrete buildings in Australia}, journal = {Australian Journal of Structural Engineering}, volume = {20}, year = {2019}, month = {05/2019}, pages = {143-158}, abstract = {

The project {\textquoteleft}Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquoteright} under the Bushfire and Natural Hazards Cooperative Research Centre (BNHCRC) aims to develop knowledge to facilitate evidence-based informed decision-making in relation to the need for seismic retrofitting, revision of codified design requirements and insurance policy. Seismic vulnerability assessment is an essential component in the project. The objective of this paper is to present the framework for carrying out vulnerability assessment of limited-ductile reinforced concrete (RC) buildings in Australia. This paper is organised into four parts: (i) overview of typical building construction in Australia and description of the three broad categories of vulnerable RC buildings identified by the authors; (ii) identification and overview of case study buildings for seismic vulnerability assessment; (iii) definition and description for each performance level and damage state, including recommended material strain limits and drift limits for RC buildings; and (iv) hazard-consistent ground motion inputs for dynamic analyses.

}, keywords = {RC buildings, regions of lower seismicity, Seismic vulnerability assessment, seismic vulnerability of RC buildings}, doi = {https://doi.org/10.1080/13287982.2019.1611034}, url = {https://www.tandfonline.com/doi/abs/10.1080/13287982.2019.1611034}, author = {Scott Menegon and Hing-Ho Tsang and Elisa Lumantarna and Nelson Lam and John Wilson and Emad F Gad} } @conference {bnh-6388, title = {How Safe is Safe Enough? Melbourne Case Study}, booktitle = {Australian Earthquake Engineering Society 2019 Conference}, year = {2019}, month = {12/2019}, address = {Newcastle}, abstract = {

Residual risk exists in our buildings even if they were designed in conformance with modern codes of practice. The risk of being killed by earthquakes in Melbourne was discussed in the AEES 2018 Conference (Tsang et al. 2018a). This follow-up paper attempts to address a fundamental question in seismic design: {\textquotedblleft}How Safe is Safe Enough?{\textquotedblright} Various approaches have been implemented or proposed in the last decade for setting risk-targeted performance requirements for seismic design. A target collapse risk limit for a single building may be considered very low by some; however, the aggregated risk for society could become significant, especially for a metropolitan city like Melbourne. This paper introduces an approach proposed by the authors (refer Tsang et al. 2019for full details and discussion)for evaluating the adequacy of existing code level for collapse prevention and life safety by comparing societal risk functions based on regional earthquake loss modelling with a proposed regulatory requirement that aims to limit the earthquake mortality rate to {\textquotedblleft}as low as reasonably practicable (ALARP){\textquotedblright}. The proposed approach is then applied to Melbourne in a case study. The results show that the earthquake fatality risk for society appears to be unacceptable.

}, keywords = {building, Collapse, earthquake, Earthquake fatality, F-N function, Societal risk}, url = {https://aees.org.au/wp-content/uploads/2019/12/66-Hing-Ho-Tsang.pdf}, author = {Hing-Ho Tsang and James Daniell and Friedemann Wenzel and John Wilson} } @article {bnh-6055, title = { Innovative Upscaling of Architectural Elements for Strengthening Building Structures}, journal = {Sustainability}, volume = {11}, year = {2019}, month = {05/2019}, pages = {2636}, abstract = {

For conservation of heritages or life prolongation of aged buildings that contributes to environmental sustainability, there is a global need of structural strengthening or upgrading so as to restore their original functions or fulfil more stringent performance requirements stipulated in modern design codes of practice. However, the actual implementation is usually met with resistance from the property owner; hence, it is desirable to adopt an effective, economical and less invasive technique. In order to provide a further incentive, this article explores an innovative idea of upscaling decorative architectural elements, such as brackets, knee braces and corbels, in order that they also possess adequate strength capacity to resist extreme loadings such as earthquake actions. The required dimensions of architectural brackets for seismic retrofitting of concrete beam-column joints are calculated for different levels of seismicity through a parametric study. It is demonstrated that the proposed design can enhance both the aesthetics and structural performance of a building. This exemplifies how art can be integrated into engineering design for solving real-world problems.\ 

}, keywords = {building structure; strengthening; seismic retrofitting; aesthetic; heritage; conservation; architectural element; reinforced concrete; connection; structural art}, doi = {https://doi.org/10.3390/su11092636}, url = {https://www.mdpi.com/2071-1050/11/9/2636}, author = {Hing-Ho Tsang} } @article {bnh-6129, title = {Progress report on costing of limited ductile reinforced concrete buildings}, number = {520}, year = {2019}, month = {10/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

{\textquotedblleft}Cost-effective mitigation strategy development for building related earthquake risk{\textquotedblright} under the Bushfire and Natural Hazards Cooperative Research Centre (BNHCRC) aims to develop knowledge to facilitate evidence-based informed decision making in relation to the need for seismic retrofitting, revision of codified design requirement, and insurance policy. Previous report has presented vulnerability assessment of two types of reinforced concrete (RC) buildings, RC buildings that are mainly supported laterally by limited ductile RC walls and buildings that are supported jointly by limited ductile RC walls and RC frames. The analyses demonstrate buildings that are jointly supported by RC walls and frames to be more vulnerable. This report presents summary findings of the vulnerability analyses along with descriptions for the types of damage observed for each performance levels with the aim of estimating cost of repair for this type of buildings.\ 

}, keywords = {buildings, concrete, emergency recovery, engineering, risk and safety}, issn = {520}, author = {Elisa Lumantarna and Nelson Lam and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-6050, title = {Strengthening and repair of reinforced concrete columns by jacketing: state-of-the-art review}, journal = {Sustainability}, volume = {11}, year = {2019}, month = {06/2019}, pages = {3208}, abstract = {

Sustainability necessitates the protection of infrastructure from any kind of deterioration over the life cycle of the asset. Deterioration in the capacity of reinforced concrete (RC) infrastructure (e.g., bridges, buildings, etc.) may result from localised damage sustained during extreme loading scenarios, such as earthquakes, hurricanes or tsunamis. In addition, factors such as the corrosion of rebars or ageing may also deteriorate or degrade the capacity of an RC column, thereby necessitating immediate strengthening to either extend or ensure its design life is not limited. The aim of this paper is to provide a state-of-the-art review of various strengthening and repair methods for RC columns proposed by different researchers in the last two decades. The scope of this review paper is limited to jacketing techniques for strengthening and/or repairing both normal- and high-strength RC columns. The paper also identifies potential research gaps and outlines the future direction of research into the strengthening and repair of RC columns.

}, keywords = {Infrastructure, Multi-hazard, sustainability}, doi = {https://doi.org/10.3390/su11113208}, url = {https://www.mdpi.com/2071-1050/11/11/3208}, author = {Saim Raza and Muhammad Khan and Scott Menegon and Hing-Ho Tsang and John Wilson} } @article {bnh-6141, title = {A universal approach for evaluating earthquake safety level based on societal fatality risk}, journal = {Bulletin of Earthquake Engineering}, year = {2019}, month = {10/2019}, pages = {1-24}, abstract = {

Residual risk exists in our buildings even if they were designed in conformance with modern codes of practice. Various approaches have been implemented or proposed in the last decade for setting risk-based performance requirements for seismic design of building structures. However, there is insufficient consideration about the aggregated risk for society, which could be significant especially for a densely populated metropolitan city. This paper introduces a rational and universal approach for evaluating the adequacy of structural safety requirements by comparing societal risk functions based on probabilistic loss assessment with a proposed regulatory requirement that aims to limit the mortality rate to {\textquotedblleft}as low as reasonably practicable\ (ALARP){\textquotedblright}. The proposed approach is then applied to Melbourne, Australia, in a case study, which shows that the earthquake fatality risk for the society appears to be unacceptable. The outcome can be used for justification of a seismic retrofitting policy or a required change of the design code level. The proposed scheme is also applicable to other natural hazards and for safety engineering applications generally.

}, keywords = {Building structure, Collapse, Earthquake fatality, F{\textendash}N, Seismic safety, Societal risk}, doi = {https://doi.org/10.1007/s10518-019-00727-9}, url = {https://link.springer.com/article/10.1007/s10518-019-00727-9}, author = {Hing-Ho Tsang and James Daniell and Friedemann Wenzel and John Wilson} } @article {bnh-6137, title = {Use of Macroseismic Intensity Data to Validate a Regionally Adjustable Ground Motion Prediction Model}, journal = {Geosciences }, volume = {9}, year = {2019}, month = {09/2019}, chapter = {422}, abstract = {

In low-to-moderate seismicity (intraplate) regions where locally recorded strong motion data are too scare for conventional regression analysis, stochastic simulations based on seismological modelling have often been used to predict ground motions of future earthquakes. This modelling methodology has been practised in Central and Eastern North America (CENA) for decades. It is cautioned that ground motion prediction equations (GMPE) that have been developed for use in CENA might not always be suited for use in another intraplate region because of differences in the crustal structure. This paper introduces a regionally adjustable GMPE, known as the component attenuation model (CAM), by which a diversity of crustal conditions can be covered in one model. Input parameters into CAM have been configured in the same manner as a seismological model, as both types of models are based on decoupling the spectral properties of earthquake ground motions into a generic source factor and a regionally specific path factor (including anelastic and geometric attenuation factors) along with a crustal factor. Unlike seismological modelling, CAM is essentially a GMPE that can be adapted readily for use in different regions (or different areas within a region) without the need of undertaking any stochastic simulations, providing that parameters characterising the crustal structure have been identified. In addressing the challenge of validating a GMPE for use in an area where instrumental data are scarce, modified Mercalli intensity (MMI) data inferred from peak ground velocity values predicted by CAM are compared with records of MMI of past earthquake events, as reported in historical archives. South-Eastern Australia (SEA) and South-Eastern China (SEC) are the two study regions used in this article for demonstrating the viability of CAM as a ground motion prediction tool in an intraplate environment.

}, keywords = {Attenuation, crustal model, GMPE, intraplate region, MMI, seismic hazard}, doi = {https://doi.org/10.3390/geosciences9100422 }, url = {https://www.mdpi.com/2076-3263/9/10/422}, author = {Yuxiang Tang and Nelson Lam and Hing-Ho Tsang and Elisa Lumantarna} } @article {bnh-5198, title = {Report on fragility curves for limited ductile reinforced concrete buildings}, year = {2018}, month = {12/2018}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Reinforced concrete buildings make up the majority of Australian building stocks.\ Structural elements of these buildings are often designed with limited to\ nonductile detailing. With a very low building replacement rate many of the\ Australian buildings are vulnerable to major earthquakes and pose significant risk\ to lives, properties and economic activities.

"Cost-effective mitigation strategies for building-related earthquake risk{\textquotedblright} under the Bushfire and Natural Hazards Cooperative\ Research Centre (BNHCRC) aims to develop knowledge to facilitate evidencebased\ informed\ decision\ making\ in\ relation\ to\ the\ need\ for\ seismic\ retrofitting,\ revision\ of codified design requirement, and insurance policy. Seismic\ vulnerability assessment is an essential component in the project.\ 

This report presents sets of fragility curves that have been developed for two types of reinforced concrete buildings, buildings that are mainly supported by shear or core walls and buildings that are supported by walls and moment resisting frames. The seismic assessment frameworks, the approach for selection of ground motions and the development of archetype building models will be discussed. The fragility curves for low-rise, mid-rise and high-rise buildings for both types of limited ductile reinforced concrete buildings will be presented in the forms of PGV, MMI and RSDmax as intensity measures.

}, issn = {433}, author = {Elisa Lumantarna and Helen M. Goldsworthy and Nelson Lam and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-4692, title = {Seismic retrofit of exterior RC beam-column joint using diagonal haunch}, journal = {Engineering Structures}, volume = {174}, year = {2018}, month = {01/2018}, abstract = {

Exterior beam-column joint is typically the weakest link in a limited-ductile RC frame structure. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for reducing the seismic demand at the joint. Previous research globally has focused on implementing double haunches, whilst the performance of using single haunch element as a less-invasive and more architecturally favourable retrofit option has not been investigated. In this study, the feasibility of using a single haunch system for retrofitting RC exterior beam-column joint is explored. This paper presents the derivation of the key formulations for the implementation of a single diagonal haunch as well as the generalization of the formulations for all three systems: the non-retrofitted subassembly, the double haunch retrofitting system, and the single haunch retrofitting system. The formulations have then been validated by available experimental data for non-retrofitted subassembly and double haunch retrofitting system. Finally, the effectiveness of the single haunch retrofitting system is compared with that of the double haunch retrofitting system through a parametric study.

}, keywords = {Exterior beam-column joint, limited-ductile, RC frame, Seismic retrofit, Single diagonal haunch.}, doi = {10.1016}, url = {https://www.sciencedirect.com/science/article/pii/S0141029617328857}, author = {Zabihi, Alireza and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-5009, title = {Seismic retrofit of precast soft-storey building using diagonal steel-shape memory alloy bracing device: Numerical investigation}, journal = {Advances in Structural Engineering}, year = {2018}, month = {10/2018}, abstract = {

A diagonal steel-shape memory alloy bracing device is proposed for seismic retrofitting of vulnerable building frame structure. Superelastic shape memory alloy bar is put in series with steel bars in the bracing. The device makes use of the loading plateau of superelastic shape memory alloy to limit the tensile force of diagonal bracing. A precast soft-storey building frame in Australia was selected for a case study. A numerical model of the frame was developed and validated with the results from full-scale pull-down field tests. Nonlinear time history analysis was then conducted to evaluate the seismic performance of the frame with different retrofitting strategies. The result shows that the diagonal steel-shape memory alloy bracing can reduce the displacement demand on the soft-storey frame. Meanwhile, the level of tensile force of steel-shape memory alloy bracing can be controlled by the force plateau of the shape memory alloy bar, which is recommended to be 20\% of the yielding force of the steel bar. The lower tensile force demand could alleviate the force demand at the associated support connections.

}, keywords = {diagonal bracing, retrofit, shape memory alloy, soft-storey building, superelastic}, doi = {10.1177/1369433218800939}, url = {http://journals.sagepub.com/doi/abs/10.1177/1369433218800939}, author = {John Wilson and Hing-Ho Tsang and Xiaoxian Liu} } @article {bnh-5160, title = {Unified models for post-peak failure drifts of normal- and high-strength RC columns}, journal = {Magazine of Concrete Research}, volume = {70}, year = {2018}, month = {11/2018}, pages = {1101}, chapter = {1081}, abstract = {

Displacement-based design of reinforced-concrete (RC) columns requires reliable estimation of the drift capacity beyond the elastic range. Although many post-peak drift models exist for normal-strength RC (NSRC) columns, very limited work has been done in this area on high-strength RC (HSRC) columns. This paper evaluates the capability of existing drift models to predict post-peak drift capacity of both NSRC and HSRC columns. A comparative study is conducted using a comprehensive database of 190 RC columns (79 HSRC and 111 NSRC) from past experimental studies. The results of the comparative study indicate that most of the existing drift models overestimate post-peak drift capacity of HSRC columns, primarily because the influence of concrete strength has been ignored. This paper also proposes a unified set of empirical drift models that have a unique ability to predict post-peak drift capacity of lightly to moderately reinforced NSRC as well as HSRC columns. The new models can serve as tools for structural design engineers to estimate drift capacity of RC columns at an early design stage. Moreover, the models can assess the drift performance of RC columns in existing buildings and hence can also aid in decision-making regarding the need for retrofitting.

}, doi = {https://doi.org/10.1680/jmacr.17.00375}, url = {https://www.icevirtuallibrary.com/doi/10.1680/jmacr.17.00375}, author = {Saim Raza and Hing-Ho Tsang and John Wilson} } @conference {bnh-6026, title = {Analytical Model for Seismic Retrofit of Concrete Beam-Column Joint using Diagonal Metallic Haunch}, booktitle = {World Congress on Advances in Structural Engineering and Mechanics}, year = {2017}, month = {01/09/2017}, publisher = {Swinburne University of Technology}, organization = {Swinburne University of Technology}, address = {Korea}, abstract = {

Exterior beam-column joint is typically the weakest link in a limited-ductile concrete frame structure. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for reducing the seismic demand at the joint. Previous research globally has focused on implementing double haunches, whilst the performance of using single haunch element as a less-invasive and more architecturally favourable retrofit option has not been investigated. In this study, the feasibility of using a single haunch system for retrofitting RC exterior beam-column joint is explored. This paper presents the key formulations and illustrates its effectiveness by investigating the changes in the shear demand at the joint through a case study.

}, keywords = {building, building disaster proof, construction, Emergency management, engineering, hazards, risk management}, author = {Hing-Ho Tsang and Zabihi, Alireza and Emad F Gad and John Wilson} } @article {bnh-5093, title = {Application of hybrid simulation for collapse assessment of post-earthquake CFRP-repaired RC columns}, journal = {ASCE Journal of Structural Engineering}, volume = {143}, year = {2017}, month = {01/2017}, abstract = {

Hybrid simulation combines the flexibility and cost-effectiveness of computer simulations with the realism of experimental testing to provide a powerful platform for large-scale experimental investigation of the seismic response of structures through collapse. This paper presents applications of hybrid simulation for (1)\ tracing the seismic response of a limited-ductility reinforced-concrete (RC) column through collapse and (2)\ evaluating the capability of carbon fiber reinforced polymer (CFRP) repair on rehabilitating the earthquake-damaged RC column to its initial collapse resistance capacity. A state-of-the-art hybrid testing facility, referred to as the multiaxis substructure testing (MAST) system, was used to simulate complex time-varying six-degrees-of-freedom (6-DOF) boundary effects on the physical specimens using mixed load/deformation modes. Based on the experimental results, a comparative collapse risk assessment of the initial and repaired column was conducted, which illustrates the effectiveness of using CFRP repair to restore and improve the collapse resistance of earthquake-damaged RC columns.

}, doi = {https://doi.org/10.1061/(ASCE)ST.1943-541X.0001629}, url = {https://ascelibrary.org/doi/10.1061/\%28ASCE\%29ST.1943-541X.0001629}, author = {Mojgen Hashemi and Al-Ogaidi, Y and Al-Mahaidi, R and Robin Kalfat and Hing-Ho Tsang and John Wilson} } @article {bnh-5087, title = {Collapse assessment of reinforced concrete building columns through multi-axis hybrid simulation}, journal = {ACI Structural Journal}, volume = {114}, year = {2017}, month = {01/2017}, abstract = {

One of the major challenges in collapse assessment of reinforced concrete (RC) structures has been the lack of realistic data obtained from reliable experimental loading protocols that are capable of accurately quantifying the reserve capacity of RC structures beyond the design level to the state of complete collapse. Until now, quasi-static (QS) symmetrically cyclic or monotonic tests with constant axial load have been commonly used, which are not adequate to accurately capture the actual response of a collapsing RC structure in real earthquake events. Hybrid simulation (HS) can be considered an attractive alternative to realistically simulate more complex boundary conditions and improve response prediction of a structure from elastic range to collapse. This paper presents a comparative experimental study on two identical, large-scale, limited-ductility RC columns that are tested to collapse through QS and HS, respectively. The RC columns serve as the first-story corner-column of a half-scale symmetrical five-byfive-bay five-story RC ordinary moment frame building structure. A state-of-the-art facility, referred to as a multi-axis substructure testing (MAST) system, is used that is capable of controlling all six-degrees-of-freedom (6-DOF) boundary conditions in mixed load and deformation modes. The load protocol in the QS test includes constant axial load combined with bidirectional lateral deformation reversals, while in the HS, more realistic boundary effects including fluctuation in axial load and the ratcheting behavior (that is, asymmetrical lateral deformation prior to collapse) are simulated. The hysteretic response behaviors obtained from the QS and HS tests are then used for calibrating the analytical models employed in a comparative collapse risk assessment. The results show that the improved interface boundary effects lead to significant changes in hysteretic response and the calibration parameters and, as a result, estimating the probability of collapse. This highlights that the credibility of collapse assessment results relies to a great extent on the application of correct boundary interface on RC columns.

}, url = {https://www.concrete.org/publications/internationalconcreteabstractsportal/m/details/id/51689438}, author = {Mojgen Hashemi and Hing-Ho Tsang and Al-Ogaidi, Y and John Wilson and Al-Mahaidi, R} } @article {bnh-4212, title = {Cost-effective mitigation strategy for building related earthquake risk: annual project report 2016-17}, number = {348}, year = {2017}, month = {09/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The 1989 Newcastle Earthquake caused damage to 70,000 properties, with an associated total economic loss of AU$ 4 billion. Consistently, the insurance industry has estimated the economic risk posed by a moderate earthquake in any of the capital cities in Australia to be of the order of billions of dollars. A major reason for this risk is that Australia has not designed buildings for earthquake-induced forces until 1995 so that a large portion of our building stock is seismically vulnerable.

As demonstrated in Christchurch, New Zealand, in 2010-11, a magnitude 6 earthquake can have a devastating impact on a city and country (damage rebuild estimated at ~ 20\% national GDP!) even though buildings there have been designed for earthquakes for many decades.

This project includes collaborative research from 4 partner institutions to establish:

  1. The relative vulnerabilities to earthquake shaking of the most common forms of building construction in Australia;
  2. What earthquake retrofit techniques worked and what didn{\textquoteright}t as a starting point in developing a {\textquoteleft}menu{\textquoteright} of economically feasible seismic retrofit techniques that could be used in Australian cities;
  3. With industry end-user support, conduct proof of concept tests on some of the most promising seismic retrofit techniques on buildings scheduled for demolition by the SA state government;
  4. Use the new damage and economic loss models developed over the first 3 years of this project to undertake a seismic risk assessment case study of the Melbourne metro area; and
  5. Advance a series of end user focused research utilization projects in the areas of improved building regulation, community risk reduction, design profession guidance and insurance industry engagement with their policy holders. These will include an Earthquake Mitigation Case Study for the historic town of York in Western Australia and Development of a Rapid Visual Screening procedure for Australian buildings

Finally, using the new damage loss models and costings for seismically retrofitting buildings, make recommendations for the development of seismic retrofit guidelines and policy based on the strong evidence base developed.

}, issn = {348}, author = {Michael Griffith and Hossein Derakhshan and Elisa Lumantarna and Hing-Ho Tsang and Helen M. Goldsworthy and John Wilson and Nelson Lam and Mark Edwards} } @article {bnh-5089, title = {A design spectrum model for flexible soil sites in regions of low-to-moderate seismicity}, journal = {Soil Dynamics and Earthquake Engineering}, volume = {92}, year = {2017}, month = {2017}, pages = {36-45}, chapter = {36}, abstract = {

Design spectrum (DS) models in major\ codes of practice\ for\ structural designof buildings typically stipulate empirical site factors for each of the five, or six, site classes. Although the phenomenon of resonant like amplification behaviour of the structure caused by multiple\ wave reflections\ is well known, the potentials for such periodic amplification behaviour are not explicitly considered in code models. This is partly because of expert opinion that such effects are very {\textquotedblleft}localised{\textquotedblright} in the frequency domain and can be suppressed readily by damping. However, investigations into the risk of collapse of non-ductile, and irregular structural systems, common in regions of low-to-moderate\ seismicity, revealed the extensive influence of periodic base excitations on flexible soil sites (with initial small-strain natural period\ Ti\>0.5s). In this paper, an alternative DS model which addresses the important phenomenon of soil resonance without the need of computational site\ response analysis\ of the subsurface model of the site is introduced.

}, doi = {https://doi.org/10.1016/j.soildyn.2016.09.035}, url = {https://www.sciencedirect.com/science/article/pii/S0267726116303219}, author = {Hing-Ho Tsang and John Wilson and Nelson Lam and Ray Kai Leng Su} } @article {bnh-5090, title = {A refined design spectrum model for regions of lower seismicity}, journal = {Australian Journal of Structural Engineering}, volume = {18}, year = {2017}, month = {03/2017}, abstract = {

This paper presents a refined site classification scheme and a design spectrum (DS) model for different site conditions, with site natural period as the key classification parameter. The refined model has a particular emphasis on the phenomenon of resonant-like amplification behaviour in soil sites, which have not been explicitly considered in any existing code models. The need to address the effects of soil resonance and increased displacement demand is particularly justified in regions of lower seismicity, where structures are typically of limited ductility with low energy dissipation capability. Significantly, the mitigating effects of a very flexible soil site resulting in reduction in the level of seismic demand on low-rise buildings is a distinctive feature of the model which has been well validated by comparison with results obtained from computational site response analysis of soil columns derived from real borehole records, as well as from strong motion data recorded in the 1994 Northridge earthquake.

}, doi = {https://doi.org/10.1080/13287982.2017.1297529}, url = {https://www.tandfonline.com/doi/abs/10.1080/13287982.2017.1297529}, author = {Hing-Ho Tsang and John Wilson and Nelson Lam} } @conference {bnh-6028, title = {Analytical development of seismic retrofit technique for RC beam-column joint using single diagonal haunch}, booktitle = {24th Australian Conference on the Mechanics of Structures and Materials}, year = {2016}, month = {12/2016}, publisher = {Swinburne University of Technology}, organization = {Swinburne University of Technology}, address = {Perth, Australia}, abstract = {

Exterior beam-column joint is typically the weakest link in a limited-ductile RC frame structure. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for preventing brittle failure of the joint. Previous research has been focused on implementing double haunches, whilst the performance of using single haunch element as a less-invasive and more architecturally favourable retrofit option has not been investigated. Hence, the feasibility of using single haunch system for retrofitting RC beam-column joint is explored in this study. This paper presents the analytical development of the technique and illustrates its effectiveness by showing the changes in the shear demand at the joint.

}, keywords = {building, construction, earthquake, engineering, retrofitting, risk management}, author = {Zabihi, Alireza and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-5077, title = {Minimum loading requirements for areas of low seismicity}, journal = {Earthquakes and Structures}, volume = {11}, year = {2016}, pages = {539-561}, chapter = {539}, abstract = {

The rate of occurrence of intraplate earthquake events has been surveyed around the globe to ascertain the average level of intraplate seismic activities on land. Elastic response spectra corresponding to various levels of averaged (uniform) seismicity for a return period of 2475 years have then been derived along with modifying factors that can be used to infer ground motion and spectral response parameters for other return period values. Estimates derived from the assumption of uniform seismicity are intended to identify the minimum level of design seismic hazard in intraplate regions. The probabilistic seismic hazard assessment presented in the paper involved the use of ground motion models that have been developed for regions of different tectonic and crustal classifications. The proposed minimum earthquake loading model is illustrated by the case study of Peninsular Malaysia which has been identified with a minimum effective peak ground acceleration (EPGA) of 0.1 g for a return period of 2475 years, or 0.07 g for a notional return period of 475 years.

}, doi = {https://doi.org/10.12989/eas.2016.11.4.539}, url = {http://koreascience.or.kr/article/ArticleFullRecord.jsp?cn=TPTPJW_2016_v11n4_539}, author = {Nelson Lam and Hing-Ho Tsang and Elisa Lumantarna and John Wilson} } @conference {bnh-6008, title = {Retrofitting RC Beam-Column Joint in Australia using Single Diagonal Haunch}, booktitle = {Australian Earthquake Engineering Society 2016 Conference}, year = {2016}, month = {11/2016}, publisher = {Australian Earthquake Engineering Society}, organization = {Australian Earthquake Engineering Society}, address = {Melbourne}, abstract = {

Exterior beam-column joint is potentially the weakest link in a limited-ductile RC frame structure in Australia. The use of diagonal haunch element has been considered as a desirable seismic retrofit option for preventing brittle failure of the joint. Previous research globally has focused on implementing double haunches, whilst the performance of using single haunch element as a less-invasive and more architecturally favourable retrofit option has not been investigated. In this study, the feasibility of using a single haunch system for retrofitting RC beam-column joint in Australia is explored. This paper presents the key formulations of the technique and illustrates its effectiveness by showing analytically the changes in the shear demand at the joint.

}, keywords = {Exterior beam-column joint, limited-ductile, RC frame, seismic retrofitting, single haunch}, author = {Zabihi, Alireza and Hing-Ho Tsang and Emad F Gad and John Wilson} } @article {bnh-4667, title = {Seismic Vulnerability Assessment of Asymmetrical Reinforced Concrete Buildings in Australia}, journal = {Australian Earthquake Engineering Society }, year = {2016}, month = {11/2016}, abstract = {

Many reinforced concrete buildings in Australia are laterally supported by reinforced concrete cores/shear walls that are eccentrically located in the buildings. The structural elements at the edges of the asymmetrical buildings can be subjected to a significant displacement demand, making this type of buildings highly vulnerable in an earthquake. Seismic assessment methods for asymmetrical buildings commonly involve three-dimensional dynamic analyses that can be computationally expensive. This paper presents a simplified analysis method for multi-storey buildings featuring plan asymmetry. The method has been used to assess the seismic vulnerability of asymmetrical reinforced concrete buildings in Australia.

}, keywords = {Aymmetrical buildings, fragility curves, reinforced concrete., simplified analysis method}, url = {https://www.aees.org.au/wp-content/uploads/2018/06/379-Lumantarna-et-al.pdf}, author = {Elisa Lumantarna and Alireza Mehdipanah and Nelson Lam and Hing-Ho Tsang and John Wilson and Emad F Gad and Helen M. Goldsworthy} } @article {bnh-3464, title = {Local intraplate earthquake considerations for Singapore}, journal = {The IES Journal Part A: Civil \& Structural Engineering}, volume = {8}, year = {2015}, month = {11/2014}, pages = {62-70}, chapter = {62}, abstract = {

The current National Annex for Singapore to Eurocode 8 is primarily to address distant hazards from Sumatra and is not intended to provide coverage for potential local intraplate hazards. The latter type of hazards has safety implications on low-rise structures including many of the aged building construction. It is argued that the absence of local seismic activities in the recorded history within the Malaysian peninsular cannot be used as evidence to justify the assumption that its level of potential local hazards is any lower than other intraplate regions such as Australia, Southern India, and Central and Eastern United States, because of the relative smallness of the landmass of the peninsular. This paper presents a response spectrum model for intraplate earthquakes using relevant data from other regions around the world as opposed to relying on very limited amount of data from regional monitoring. Finally, a response spectrum model that takes into account potential threats from both distant and local seismic sources is recommended for future adoption by Singapore.

}, doi = {http://dx.doi.org/10.1080/19373260.2014.974873}, url = {http://www.tandfonline.com/doi/abs/10.1080/19373260.2014.974873?journalCode=tiea20}, author = {Nelson Lam and Hing-Ho Tsang and Elisa Lumantarna and John Wilson} } @conference {bnh-2510, title = {Recommended Site Classification Scheme and Design Spectrum Model for Regions of Lower Seismicity}, booktitle = {Tenth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Pacific }, year = {2015}, month = {11/2015}, address = {Sydney, Australia}, abstract = {

This paper proposes a site classification scheme and a design spectrum (DS) model for different ground conditions, with site natural period as the key parameter. The proposed model has a particular emphasis on the phenomenon of resonant-like amplification behaviour in soil sites, which have not been explicitly considered in existing code models. The need to address the effects of soil resonance is particularly justified in regions of lower seismicity, where structures are typically of limited ductility with low energy dissipation capability. Significantly, the mitigating effects of a very flexible soil site resulting in reduction in the level of seismic demand on low rise buildings is a distinctive feature of the proposed model which has been well validated by comparison with results obtained from computational site response analysis of soil columns derived from real borehole records, as well as from strong motion data recorded in the 1994 Northridge earthquake.

}, author = {Hing-Ho Tsang and John Wilson and Nelson Lam} }