@article {bnh-7971, title = {The Selection and Scaling of Ground Motion Accelerograms for Use in Stable Continental Regions}, journal = {Journal of Earthquake Engineering}, year = {2021}, month = {04/2021}, abstract = {

This paper presents an application of the Conditional Mean Spectrum (CMS) methodology for sourcing accelerogram records for use in dynamic analyses of structures in intraplate regions of lower seismicity. The main challenges with deriving CMS for selecting and scaling accelerograms in regions of lower seismicity stem from the paucity of representative strong motion data and event recurrence data. A step-by-step illustration of the methodology is presented using the south-eastern Australia (SEA) region as an example. The study involves making use of a diversity of Ground Motion Prediction Expressions (GMPEs) including a recently developed regionally adjustable Component Attenuation Model (CAM). Three different schemes using a weighted averaging of candidate GMPEs were adopted and a comparison of predictions demonstrated only minor differences confirming the robustness of the modelling. The CMS constructed in this study have been used to develop a proposed suite of scaled accelerograms for SEA.

}, keywords = {Component attenuation model, Conditional mean spectra, earthquake, engineering, ground motion selection, stable continental region}, doi = {https://doi.org/10.1080/13632469.2021.1913456}, url = {https://www.tandfonline.com/doi/abs/10.1080/13632469.2021.1913456?journalCode=ueqe20}, author = {Yiwei Hu and Nelson Lam and Scott Menegon and John Wilson} } @article {bnh-8207, title = {Shear Wall and Frame Dual Systems Featuring Discontinuous Load Paths in Frame Elements in Low-to-Moderate Seismic Regions}, journal = {Journal of Earthquake Engineering}, year = {2021}, month = {09/2021}, abstract = {

Reinforced concrete buildings constitute a significant portion of construction in Australia. Many existing buildings in Australia and other low to moderate seismic regions have been designed with little to no consideration for ductile detailing. The majority of these buildings also possess vertical irregularities, which can exacerbate their vulnerability in an earthquake event. The seismic performance of shear wall and frame dual systems possessing discontinuities in frame elements in the form of ductility and failure mechanism has been assessed. And design recommendations in terms of response modification factors and designation of appropriate methods of analysis have been provided.

}, keywords = {Vertical irregularity; transfer beam; limited ductile buildings; response modification factor; failure hierarchy; analysis method}, doi = {https://doi.org/10.1080/13632469.2021.1964643}, url = {https://www.tandfonline.com/doi/abs/10.1080/13632469.2021.1964643}, author = {Alireza Mehdipanah and Elisa Lumantarna and Nelson Lam} } @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-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-7575, title = {Modeling of Seismic Actions on Earth Retaining Structures}, journal = {Recent Advances in Computational Mechanics and Simulations}, volume = {103}, year = {2020}, month = {11/2020}, pages = {247-256}, abstract = {

Present work deals with numerical modeling of seismic actions on earth retaining structures. Finite element (FE) analyses have been carried out on scaled-down retaining wall models. The capability of finite element models has been evaluated for the replication of shaking table experiment results. It was observed that FE models are highly sensitive to assigned nonlinear material models, especially for hardening and softening behavior of backfill soil. A detailed and simplified FE modeling procedure is explained for the simulation of seismic actions on earth retaining structures.

}, keywords = {Finite element modeling, Retaining wall, Shaking table experiment, Similitude}, doi = {https://doi.org/10.1007/978-981-15-8138-0_20}, url = {https://link.springer.com/chapter/10.1007/978-981-15-8138-0_20}, author = {Rohit Tiwari and Nelson Lam and Elisa Lumantarna} } @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} } @conference {bnh-6389, title = {Development of Cost-effective Mitigation Strategy for Limited Ductile Reinforced Concrete Buildings}, booktitle = {Australian Earthquake Engineering Society 2019 Conference}, year = {2019}, month = {12/2019}, address = {Newcastle}, abstract = {

With the new awareness that most Australian reinforced concrete (RC) buildings have not been designed to withstand seismic actions, and are considered to have limited ductility, it is essential to consider retrofitting options. This study aims to evaluate the seismic performance of an archetypal Australian RC building, and then implement various retrofit techniques to find the most suitable retrofit. The structural performance of the buildings before and after various retrofitting were compared to study the effectiveness of the proposed methods as well as the effect on the seismic hazard design factor. SeismoStruct software was used to perform the nonlinear analysis of the structures. This paper contributes to a research with the overall aim of assessing the seismic performance of existing buildings and their expected failure modes, impact of retrofitting measures, and the associated costs.

}, keywords = {earthquake, existing structures, limited ductility buildings, performance validation, seismic evaluation and retrofitting}, url = {https://aees.org.au/wp-content/uploads/2019/12/55-Raneem-Alazem.pdf}, author = {Raneem Alazem and Elisa Lumantarna and Nelson Lam and Scott Menegon} } @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-6387, title = {Predicting Maximum Displacement Demand of Asymmetric Reinforced Concrete Buildings}, booktitle = {Australian Earthquake Engineering Society 2019 Conference}, year = {2019}, month = {12/2019}, address = {Newcastle}, abstract = {

Reinforced concrete buildings make up the majority of Australian building stocks. The buildings generally consist of core walls and/or shear walls as lateral load carrying elements and moment resisting frames as gravitational load carrying elements. The core and/or shear walls are often eccentrically located in the buildings resulting in a large displacement demand on the moment resisting frames that are located at the edge of the buildings. Seismic assessment methods for asymmetrical buildings commonly involve three-dimensional dynamic analyses that can be computationally expensive. This paper presents a simplified analysis method that has been developed to provide estimates for the maximum displacement demand of multi-storey buildings featuring plan asymmetry. The studies form a part of a collaborative research under the Bushfire and Natural Hazards Cooperative Research Centre (BNHCRC)on {\textquotedblleft}cost-effective mitigation strategy development for building related earthquake risk{\textquotedblright}.

}, keywords = {asymmetrical buildings, reinforced concrete, simplified analysis method, torsion}, url = {https://aees.org.au/wp-content/uploads/2019/12/43-Elisa-Lumantarna.pdf}, author = {Elisa Lumantarna and Nelson Lam and John Wilson} } @conference {bnh-6390, title = {Prioritisation strategy for seismic retrofitting of reinforced concrete buildings in Australia}, booktitle = {Australian Earthquake Engineering Society 2019 Conference}, year = {2019}, month = {12/2019}, address = {Newcastle}, abstract = {

This paper presents a study on the seismic evaluation and retrofit of limited ductile reinforced concrete (RC) buildings, which make up the bulk of built infrastructure in the central building districts and high-density residential areas in Australian cities. In low to moderate seismicity regions such as Australia, RC buildings will have structural elements that have been designed with limited to no ductility. The individual building needs to be assessed and ranked for their retrofitting priority. An assessment for retrofitting methodology involving a three-tiered approach will be introduced in this paper. The assessment framework including a tiered approach was developed to evaluate the potential vulnerability of Australian RC buildings and to facilitate decision making in relation to the need for seismic retrofitting. Structural threshold values related to the vulnerable features introduced in the framework were also investigated to support the identification process of the method. It is expected that the developed three-tiered methodology will provide a significant contribution to the seismic evaluation and retrofit of existing RC buildings in Australia.

}, keywords = {reinforced concrete building, seismic evaluation and retrofitting, tiered methodology}, url = {https://aees.org.au/wp-content/uploads/2019/12/21-Bin-Xing.pdf}, author = {Bin Xing and Elisa Lumantarna and Nelson Lam and Scott Menegon} } @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-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-5159, title = {Analytical modelling of podium interference on tower walls in buildings}, journal = {Australian Journal of Structural Engineering}, volume = {18}, year = {2017}, month = {11/2017}, abstract = {

In regions of low-to-moderate seismicity like Australia, a common form of building construction is the one featuring a podium structure that supports a tower with smaller floor plan. This building layout is particularly favoured in metropolitan regions as it can cater for a mix of commercial and residential functionalities. This paper investigates the undesirable effects of podium interferences on the shear demands on the structural walls at and above the interface zone. Shear force redistributions between the connected structural walls were found to be the direct consequence of the differential restraints imposed by the podium structure. The generation of in-plane strutting forces in the slabs and beams connecting the structural walls was also found to be proportional to the extent of the deformation incompatibility between the walls and columns above the podium level. An analytical model is proposed herein for estimating in-plane strutting forces in the connecting slabs (or beams). The model has been verified against results obtained from finite element analyses using 2D, and 3D, sub-assemblages of the building. Deficiencies in the conventional diaphragm modelling approaches have been highlighted, and optimal solutions are proposed.

}, doi = {https://doi.org/10.1080/13287982.2017.1396870}, url = {https://www.tandfonline.com/doi/abs/10.1080/13287982.2017.1396870?journalCode=tsen20}, author = {Mehair Yacoubian and Nelson Lam and Elisa Lumantarna and John Wilson} } @article {bnh-4506, title = {Assessment of Displacement Demand for Earth Retaining Structures}, journal = {Australian Earthquake Engineering Society}, year = {2017}, abstract = {

Earth retaining walls and bridge abutments are part of the key infrastructure in support of a modern transportation system. Assessment of the structural safety of a retaining wall in seismic conditions is considered in this paper. Present work deals with systematic review of analytical modelling of seismic actions on retaining walls. Experimental investigation for finding displacement demand of scaled down retaining wall models has been discussed. A detailed experimental investigation has been recommended for ensuring the accuracy of the analytical modelling approach.

}, keywords = {abutment, displacement, performance, Retaining wall, seismic, similitude.}, url = {http://www.aees.org.au/wp-content/uploads/2018/02/453-Rohit-Tiwari.pdf}, author = {Rohit Tiwari and Nelson Lam and Elisa Lumantarna} } @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-5158, title = {Effects of podium interference on shear force distributions in tower walls supporting tall buildings}, journal = {Engineering Structures}, volume = {148}, year = {2017}, month = {10/2017}, abstract = {

High rise constructions featuring a podium surrounding tower walls are often favoured for the versatile functionality of the building. It is shown in this paper that the podium can impose significant differential restraint on coupled tower walls. Incompatible tower wall displacements under lateral loads were found to be the main contributor to the generation of in-plane strutting forces in floors above and below the podium-tower interface level. Shear force localisations in the interior tower wall immediately above the interface was found to be the direct consequence of these actions. Key parameters contributing to this detrimental shear force localisation in a tower wall were analysed by way of parameter studies on representative models of the building and sub-assemblages. It is revealed that the in-plane rigid diaphragm assumption commonly adopted in practice can significantly suppress compatibility forces generated within the building floor leading to unconservative design of the tower walls. Elaborate nonlinear model has been examined to showcase the consequences of understating the shear demands on these walls.

}, doi = {https://doi.org/10.1016/j.engstruct.2017.06.075}, url = {https://www.sciencedirect.com/science/article/pii/S0141029616305454?via\%3Dihub}, author = {Mehair Yacoubian and Nelson Lam and Elisa Lumantarna and John Wilson} } @conference {bnh-4334, title = {Methods of structural analysis of buildings in regions of low to moderate seismicity}, booktitle = {2017 World Congress on Advances in Structural Engineering and Mechanics}, year = {2017}, month = {09/2017}, address = {Seoul, Korea}, abstract = {

The paper introduces simplified methods for the analysis of multi-storey buildings for regions of low to moderate seismicity. Due to functional and architectural requirement most newly designed and existing buildings feature irregularities. The irregularities can be in a form of vertical irregularity (caused by discontinuity in load carrying elements) and plan irregularity (caused by cores that are eccentric ally placed within the buildings). Contemporary earthquake design standards and assessment procedures require dynamic analyses to be performed on such structures. However, dynamic analyses can be computationally expensive and require expert judgment, especially as far as three-dimensionally modelling is involved.

The early part of the paper presents the simplified method for the analysis of torsionally balanced (TB) buildings. Generalised modal displacements that were derived from parametric studies involving multi-storey buildings with vertical irregularities are introduced. The simplified method has been extended to account for the effects of torsion due to plan asymmetry to produce estimates of the maximum displacement demand at the edges of torsionally unbalanced (TU) buildings.

}, author = {Elisa Lumantarna and Alireza Mehdipanah and Nelson Lam and John Wilson} } @article {bnh-4505, title = {Methods of Structural Analysis of Buildings Incorporating Higher Modes Effects}, journal = {Australian Earthquake Engineering Society }, year = {2017}, pages = {10}, abstract = {

Dynamic analysis method has been suggested for the analysis of irregular buildings in the seismic standards. However, dynamic analyses can be computationally expensive and there are uncertainties associated with the selection of ground motion records for the regions of low to moderate seismicity. In a relevant research by the authors, it has been shown that linear response of irregular buildings featuring transfer beams resembles the response of regular buildings in the regions of low to moderate seismicity such as Australia. Hence, Generalised Lateral Force Method (GLFM) of Analysis is introduced and developed to incorporate the effects of higher modes based on generic modal displacement values. This method can be used for shear wall dominant RC buildings with or without transfer beam irregularity features. Shortcomings of the conventional Equivalent Static Analysis Method are resolved and the robustness of the method in estimating the seismic demands within the elastic limit is demonstrated by comparison with dynamic analyses.

}, keywords = {dynamic analysis method., higher mode effects, Multi-storey buildings, static analysis method}, url = {http://www.aees.org.au/wp-content/uploads/2018/02/463-Alireza-Mehdipanah.pdf}, author = {Alireza Mehdipanah and Elisa Lumantarna and Nelson Lam} } @article {bnh-5092, title = {RC walls in Australia: reconnaissance survey of industry and literature review of experimental testing}, journal = {Australian Journal of Structural Engineering}, volume = {18}, year = {2017}, month = {04/2017}, abstract = {

This paper presents the findings of a recent reconnaissance survey of the reinforced concrete (RC) construction industry in Australia. The survey involved the review of the structural documentation of a set of case study buildings constructed in Australia. The types of walls and observed methods of detailing are documented. Upper and lower bound values for typical wall attributes have been presented which researchers can utilise to design laboratory test specimens or perform parametric computer studies, to ensure their study accurately represents real-world conditions. A literature review of experimental testing of the lateral in-plane capacity of RC walls is included. The literature review identified 81 experimental studies, in which 501 RC wall test specimens have been tested worldwide. It is shown that very little experimental studies have been performed on RC walls that match what is being constructed in Australia.

}, doi = {https://doi.org/10.1080/13287982.2017.1315207}, url = {https://www.tandfonline.com/doi/abs/10.1080/13287982.2017.1315207}, author = {Scott Menegon and John Wilson and Nelson Lam and Emad F Gad} } @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} } @article {bnh-4669, title = {Analytical Simulation of Limited Ductile RC Beam-Columns}, year = {2016}, month = {11/2016}, abstract = {

A systematic analytical modelling technique for the simulation of limited-ductile beamcolumn elements based on the concentrated plasticity model is proposed in this paper. The modelling technique employs a backbone curve for the monotonic behaviour of the limited ductile beam-column elements based on empirical equations. The hysteretic behaviour of the beam-columns in the cyclic loading is modelled and calibrated to results from experiments on columns obtained from the literature using OpenSEES software. The modelling technique provides an important tool for the seismic performance assessment of existing buildings which have been designed with considerations of low to no ductile detailing.

}, keywords = {Bond-Slip, Concentrated Plasticity Modelling Technique, Failure Mechanisms, Lightly Reinforced Columns, OpenSEES.}, url = {https://www.aees.org.au/wp-content/uploads/2018/06/331-Alireza-Mehdipanah-et-al.pdf}, author = {Alireza Mehdipanah and Nelson Lam and Elisa Lumantarna} } @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} } @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} } @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-5098, title = {Simplified elastic design checks for torsionally balanced and unbalanced low-medium rise buildings in lower seismicity regions}, journal = {Earthquakes and Structures}, volume = {11}, year = {2016}, pages = {741-777}, chapter = {741}, abstract = {

A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.

}, doi = {10.12989/eas.2016.11.5.741}, url = {http://koreascience.or.kr/article/ArticleFullRecord.jsp?cn=TPTPJW_2016_v11n5_741}, author = {Nelson Lam and John Wilson and Elisa Lumantarna} } @article {bnh-3456, title = {Drift capacity of lightly reinforced concrete columns}, journal = {Australian Journal of Structural Engineering}, volume = {15}, year = {2015}, month = {11/2015}, pages = {131-150}, chapter = {131}, abstract = {

This paper presents the findings of a research project investigating the lateral load drift behaviour of lightly reinforced concrete columns. Such columns of limited ductility are common in regions of low-moderate seismicity, and although their strength properties are well defined, the drift performance is less understood. The paper presents the results of an experimental study undertaken and the development of a theoretical model for predicting the lateral load-drift behaviour of lightly reinforced concrete columns together with a simplified bi-linear model for checking purposes. The test results are presented and clearly indicate the dramatic impact that the axial load ratio has on the drift performance of columns of limited ductility, particularly the significantly lower drift capacities that are available in compression dominated columns.

}, doi = {10.7158/S13-002.2014.15.2}, url = {http://www.tandfonline.com/doi/pdf/10.7158/13287982.2014.11465154}, author = {Ari Wibowo and John Wilson and Nelson Lam and Emad F Gad} } @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} } @article {bnh-3454, title = {Overturning of precast RC columns in conditions of moderate ground shaking}, journal = {Earthquakes and Structures}, volume = {8}, year = {2015}, month = {2015}, pages = {1-18}, chapter = {1}, abstract = {

A simple method of assessing the risk of overturning of precast reinforced concrete columns is presented in this paper. The displacement-based methodology introduced herein is distinguished from conventional force-based codified methods of aseismic design of structures. As evidenced by results from field tests precast reinforced concrete columns can be displaced to a generous limit without sustaining damage and then fully recover from most of the displacement afterwards. Realistic predictions of the displacement demand of such (rocking) system in conjunction with the displacement capacity estimates enable fragility curves for overturning to be constructed. The interesting observation from the developed fragility curves is that the probability of failure of the precast soft-storey column decreases with increasing size of the column importantly illustrating the "size effect" phenomenon.

}, doi = {10.12989/eas.2015.8.1.001}, url = {http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=TPTPJW_2015_v8n1_1}, author = {Bidur Kafle and Nelson Lam and Elisa Lumantarna and Emad F Gad 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} } @article {bnh-3457, title = {Drift performance of lightly reinforced concrete columns}, journal = {Engineering Structures}, volume = {59}, year = {2014}, month = {02/2014}, pages = {522-535}, chapter = {522}, abstract = {

This paper presents the findings of a research project investigating the lateral load drift behaviour of lightly reinforced concrete columns. Such columns are common in regions of low{\textendash}moderate seismicity, and although their strength properties are well defined, the drift performance is less understood. The paper presents the results of an experimental study undertaken and the development of a theoretical model for predicting the lateral load{\textendash}drift behaviour of lightly reinforced concrete columns. The model includes a study undertaken to estimate the drift capacity of lightly reinforced columns at lateral load failure and axial load failure based on a large database of previous experimental tests. The results of a case study example are presented and clearly indicate the dramatic impact that the axial load ratio has on the drift performance of lightly reinforced columns, particularly the significantly lower drift capacities that are available in compression dominated columns.

}, doi = {http://dx.doi.org/10.1016/j.engstruct.2013.11.016}, url = {http://www.sciencedirect.com/science/article/pii/S0141029613005701}, author = {Ari Wibowo and John Wilson and Nelson Lam and Emad F Gad} } @article {bnh-5181, title = {Drift performance of lightly reinforced concrete columns}, journal = {Engineering Structures}, volume = {59}, year = {2014}, month = {02/2014}, pages = {522-535}, chapter = {522}, abstract = {

This paper presents the findings of a research project investigating the lateral load drift behaviour of lightly reinforced concrete columns. Such columns are common in regions of low{\textendash}moderate seismicity, and although their strength properties are well defined, the drift performance is less understood. The paper presents the results of an experimental study undertaken and the development of a theoretical model for predicting the lateral load{\textendash}drift behaviour of lightly reinforced concrete columns. The model includes a study undertaken to estimate the drift capacity of lightly reinforced columns at lateral load failure and axial load failure based on a large database of previous experimental tests. The results of a case study example are presented and clearly indicate the dramatic impact that the axial load ratio has on the drift performance of lightly reinforced columns, particularly the significantly lower drift capacities that are available in compression dominated columns.

}, doi = {https://doi.org/10.1016/j.engstruct.2013.11.016}, url = {https://www.sciencedirect.com/science/article/pii/S0141029613005701?via\%3Dihub}, author = {Ari Wibowo and John Wilson and Nelson Lam and Emad F Gad} } @article {bnh-3455, title = {Drift Performance of Point Fixed Glass Fa{\c c}ade Systems}, journal = {Advances in Structural Engineering}, volume = {17}, year = {2014}, month = {11/2014}, pages = {1481-1495}, chapter = {1481}, abstract = {

Glass fa{\c c}ade systems in buildings are subject to racking actions caused by inter storey drifts from earthquakes and wind action. The performance of fa{\c c}ade systems is dependent on the amount of imposed drift and the interaction of the glass panels with the fa{\c c}ade structural support frames. There are two major concerns related to the glass fa{\c c}ade system performance during and immediately after a seismic event; hazards to people from falling glass and the cost associated with building down time and repair. It was observed that earthquake damage to glass fa{\c c}ade systems resulting from in-plane racking actions is increasingly common and yet there has been limited research published in this field. The research completed to date has mainly focused on traditional framed glass fa{\c c}ade systems; however, the racking performance of point fixed glass fa{\c c}ade system (PFGFS) is likely to be quite different. Therefore, the aim of the research presented in this paper is to assess the in-plane racking performance of PFGFS which is a fa{\c c}ade system gaining popularity worldwide.

Two unique full scale in-plane racking laboratory tests on typical PFGFS with different types of connections were conducted and specific racking mechanisms were identified. Sophisticated non-linear finite element models (FE models) were developed and benchmarked against experimental results with excellent correlation. Further detailed FE analyses were conducted to evaluate the individual drift contributions of each racking mechanism such as rigid body translation of the glass panels at the oversize holes for construction tolerance, spider arm rotation and spider arm deformation. It was found that most of the drift capacity is attributed to the rigid body translation at the oversize holes. In this paper, the laboratory test setup and the experimental results are discussed together with the confirmatory FE analysis results to assess the in-plane racking performance of the PFGFS.

}, doi = {https://doi.org/10.1260/1369-4332.17.10.1481}, url = {http://journals.sagepub.com/doi/abs/10.1260/1369-4332.17.10.1481}, author = {S Sivanerupan and John Wilson and Emad F Gad and Nelson Lam} }