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September 2012 - November 2015
June 2007 - August 2012
Publications
Publications (73)
Resistance factors (ϕ-factors) are reliability-based factors of safety used in load and resistance factor design (LRFD) of structural systems. The ϕ-factors specified in the consensus standard for the structural design of pultruded fiber-reinforced polymer (FRP) structural members and connections are generally lower than the ϕ-factors used for more...
Strength reduction factors (ϕ-factors) are statistically based factors of safety for the load and resistance factor design of structural systems. The ϕ-factors are generally lower in current industry practice for the structural design of pultruded fiber-reinforced polymers (FRP) structural members and connections than the ϕ-factors used for more co...
Medieval churches constructed of unreinforced masonry (URM) represent critical assets of Italian architectural heritage. In order to preserve these churches against earthquakes, obtaining robust information regarding their material mechanical characteristics is necessary as part of a reliable structural analysis and strengthening intervention progr...
The rise of performance-based earthquake engineering, in combination with the complexity associated with selecting records for time-history analysis, demonstrates an expressed need for localized default suites of ground motion records for structural designers to use in the absence of site-specific studies. In the current research investigation, dea...
Bridges are fundamental links for the movement of goods and people and bridge damage can thus have significant impacts on society and the economy. Earthquakes can be extremely destructive and can compromise bridge functionality, which is essential for communities. Evaluation of bridge functionality is thus fundamental in the planning of emergency r...
Rapid seismic risk assessments are critical to help practitioners, facility stakeholders, architectural heritage superintendence, and insurance companies in their asset management decision-making processes. In particular, the integrity of the Italian church portfolio has often been threatened by earthquakes. The Italian church portfolio includes th...
A novel, integrated framework is proposed to assess the vulnerability of a case study unreinforced masonry (URM) Italian church by applying interacting modern tools including unmanned aircraft systems (UAS), “structure from motion” (SfM) photogrammetric survey equipment and software, and finite element method (FEM) analysis software in a complete h...
Completing safety evaluations of buildings is critical for the health and safety of a city’s community following a damaging earthquake. Most contemporary post-earthquake evaluations involve groups of people who physically inspect buildings, most often without training specific to evaluating earthquake damage. Three main problems arise from this pra...
Previously developed seismic risk management frameworks generally aid decision makers in determining a specific retrofit strategy. In contrast, the decision-making framework (DMF) proposed herein is used to assist property portfolio managers to determine whether a particular building should be retrofitted in the first place as part of a more holist...
The results of an investigation of the probability of earthquake damage to non-structural unreinforced masonry (URM) components are presented. The components include parapets, chimneys, and out-of-plane loaded facades typical of low-rise pre-1940 construction in Australia and New Zealand. The study is based on a street survey of component geometry,...
The architecture of Yangon, Myanmar has been heavily influenced by British colonisation from the mid-1800s, with a large portion of the historic building stock being constructed of unreinforced masonry (URM). The city’s historic buildings have regularly been exposed to the ravages of war and natural disasters, as well as low levels of maintenance d...
As a result of the 2010/2011 Canterbury, New Zealand earthquakes, Reinforced Concrete Frame with Masonry Infill (RCFMI) buildings experienced a level of damage that was different to that observed for other construction systems. An extensive survey was conducted by the Christchurch City Council and the Canterbury Earthquake Recovery Authority follow...
Small to Medium-sized Enterprises (SMEs) are often vulnerable to the adversities caused by major earthquake events, which may include business disruption, damage to goods and property, impaired employee health and safety, financial strain and loss of revenue, or even total loss of the business. SMEs are expected to make critical decisions to prepar...
Buildings constructed with reinforced concrete frames with masonry infill (RCFMI) comprise of unreinforced masonry walls that are tightly infilled into the space between the reinforced concrete frames. Poor seismic performance of RCFMI buildings has been observed during past earthquakes and it has been recurrently acknowledged that damage to masonr...
This paper provides the results of an experimental research program on the material and structural performance of a novel, innovative type of masonry unit with the potential to pro-vide safe and economic structures. The masonry block is a reinforced concrete block that uses a mortarless, interlocking connection and steel connection plates to form w...
Proof testing of multiple fired-clay-brick unreinforced masonry (URM) infill walls set within reinforced concrete frames was undertaken using airbags to simulate out-of-plane (OOP) loading. The proof testing was conducted to provide engineers in various research and practitioner roles with verified wall behaviour for the purpose of seismic assessme...
Recognising that in situ conditions for URM walls rarely reflect the idealised conditions assumed in analytical predictive models, nineteen unreinforced masonry (URM) walls in six different buildings were physically tested in situ to establish their out-of-plane (OOP) force-displacement behaviour, and the measured results were compared to the forec...
Unreinforced masonry (URM) buildings are spread around the world and represent one of the most earthquake-prone type of construction. Out-of-plane (OOP) collapse of URM buildings due to earthquake loading is typically considered the highest hazard for the population and hence a clear understanding of the walls OOP behaviour in relation to different...
Due to the large number of existing unreinforced masonry (URM) buildings worldwide, and the significant seismic risk that this building stock represents, it is important to quantify the seismic behaviour of such buildings in order to provide assessment guidance to practicing structural engineers. Current assessment guidelines have received little b...
The study of unreinforced masonry buildings and their performance in earthquakes is a topic that has led to strong Australasian collaboration amongst masonry researchers over the last decade, that has resulted in significant advances in knowledge and empirical evidence, comprehensive capture of post-earthquake 'perishable data', the development of...
The non-structural components in buildings are often subject to greater earthquake accelerations than that of the ground. This acceleration amplification is due to the building's main lateral resisting system being subject to additional 'relative' accelerations as they deform when subjected to ground motion. Floor accelerations can be conservativel...
Unreinforced masonry (URM) building construction is prominent in the form of load-bearing, partition, and infill walls. Significant out-of-plane (OOP) failures of URM walls often occur during moderate and severe earthquake shaking and such walls are often identified in structural engineering assessments as being amongst the most vulnerable elements...
Unreinforced masonry (URM) building construction is prominent in the form of loadbearing, partition, and infill walls. Significant out-of-plane (OOP) failures of URM walls often occur during moderate and severe earthquake shaking and such walls are often identified in structural engineering assessments as being amongst the most vulnerable elements...
Purpose: In the interest of advancing practice in the field of facilities management, facility asset managers dealing with regulatory environments pertaining to earthquakes and buildings can learn a great deal from the successes and short-comings of a case study programme from the Auckland Council Property Department (ACPD), which manages the publi...
Video of testing of seven-wire post-tensioning strand for free-length failure using "sand wedges"
ASCE 41 requires that the thrust force effectuated by out-of-plane arching action of masonry infill panels against the bounding frame be considered in the assessment of masonry infill walls for which arching action is relied upon. Hence, a pre-existing but incomplete model for predicting the thrust force was amended with an empirical equation used...
As territorial authorities, government agencies, and other large-asset owners were responding to regulatory and market forces in the wake of the 2010–2011 Canterbury, New Zealand, earthquakes by assessing and planning retrofits for buildings determined to be particularly vulnerable to earthquakes, an opportunity existed to identify and taxonomicall...
Brick and Block Masonry - ISBN 978-1-138-02999-6, pp 2063-2071, DOI 10.1201/b21889-271
Experimental research has been performed previously to measure the out-of-plane (OOP) seismic performance of in-situ and retrofitted unreinforced clay brick masonry (URM) walls with solid thicknesses of contiguous and overlapped masonry leaves. However, comparati...
Following the devastating 1931 Hawke’s Bay earthquake, commercial buildings in the Hawke’s Bay, New Zealand region were rebuilt in mostly homogenous structural and architectural styles. Most were constructed of reinforced concrete (RC) two-way space frames in the Art Deco aesthetic popularised during the interwar time period. Although most Art Deco...
In the aftermath of the 2010 – 2011 Canterbury earthquakes in New Zealand, the residual capacity and reparability of damaged reinforced concrete (RC) structures was an issue pertinent to building owners, insurers, and structural engineers. Three precast RC moment-resisting frame specimens were extracted during the demolition of the Clarendon Tower...
Due to the large number of existing unreinforced masonry (URM) buildings in New Zealand, and the significant seismic hazard that this building stock represents, a significant effort has been recently made to quantify the seismic behaviour of such buildings in order to provide assessment guidance to practicing structural engineers and to help inform...
Pushover analysis is a popular technique to determine the displacement capacity and failure mechanisms of assemblies of building components or global building behaviour. As pushover analysis is often used for the assessment of unreinforced masonry (URM) buildings, there is a need to benchmark existing modelling frameworks against large scale testin...
Following the 2010–2011 Canterbury earthquakes, a renewed focus has been directed across New Zealand to the hazard posed by the country’s earthquake-vulnerable buildings, namely unreinforced masonry (URM) and reinforced concrete (RC) buildings with potentially non-ductile components that have historically performed poorly in large earthquakes. The...
Extensive research has been performed previously on assessing the out-of-plane (OOP) seismic performance of unreinforced clay brick masonry (URM) walls and the retrofitting of URM loadbearing and infill walls having a solid wall thickness. However, comparatively little research has been performed pertaining to URM walls with cavities (i.e., continu...
Extensive research has been performed previously on assessing the out-of-plane (OOP) seismic performance of unreinforced fired clay brick masonry (URM) walls and the retrofitting of URM load-bearing and infill walls having a solid wall thickness. However, comparatively little research has been performed pertaining to URM walls with cavities (i.e.,...
Previous research using industry-representative standard posttensioning anchor components from the United States has shown that premature wire fractures of seven-wire, low-relaxation unbonded posttensioning strand can occur at strand strains of 0.01 or less. Building on this research, this paper describes an experimental investigation into whether...
The presented research deals with the development of statistical models for predicting seismic retrofit net construction cost (RNCC) of confined masonry (CM) buildings. Real data from 183 CM school buildings in Iran were collected to establish the RNCC and its determinant variables, among which two were unprecedented in the literature: (1) mortar q...
Following the devastating 1931 Hawke’s Bay earthquake, buildings in Napier and surrounding areas in the Hawke’s Bay region were rebuilt in a comparatively homogenous structural and architectural style comprising the region’s famous Art Deco stock. These interwar buildings are most often composed of reinforced concrete two-way space frames, and alth...
This paper describes Auckland Council’s roles and responsibilities in ensuring that the engineering of our heritage buildings is to levels of safety required legally and by the Government, the council’s own policies on building safety as an employer, and as a kaitiaki of publicly accessed heritage places. The paper describes the level of investment...
Extensive research has been performed previously on assessing the out-of-plane (OOP) performance of unreinforced masonry (URM) walls and retrofitting URM load-bearing and infill walls for OOP capacity. However, little research has been performed within New Zealand pertaining to clay brick masonry walls with cavities, despite their prominence in the...
Various methods have been developed to assess and improve the performance of buildings in earthquakes, with the goal being to reduce associated fatalities and economic losses. In the reported study, the characteristics and vulnerability of buildings constructed as reinforced concrete frames (RCF) with masonry infill that are located in the Auckland...
The 2010-2011 Canterbury earthquakes and corresponding Royal Commission reports have resulted in changes to the legislative environment and led to increased public awareness in New Zealand of the earthquake performance of unreinforced masonry (URM) buildings. As a result, building regulators, owners, tenants, users, and heritage advocates will be f...
This report represents the final submission to BRANZ regarding research project LR0441.
Extensive research has been performed previously on modelling the out-of-plane (OOP) performance of unreinforced masonry (URM) walls and retrofitting URM load-bearing and infill walls for out-of-plane capacity. However, little empirical research has been perform...
The 2010-2011 Canterbury earthquakes and corresponding Royal Commission reports have resulted in changes to the legislative environment and led to increased public awareness in New Zealand of the earthquake performance of unreinforced masonry (URM) buildings. As a result, building regulators, owners, tenants, users and heritage stakeholders will be...
As part of past hazard modelling projects in New Zealand, pilot studies have been performed to determine building typological information relevant to structural engineers and seismological hazard researchers. Relevant typological information includes construction material, structural configuration, age of the structure, number of stories, as well a...
This report describes the findings from an experimental investigation on the effects of important anchor wedge dimensional parameters on the ultimate strains and stresses of seven-wire, low relaxation unbonded post-tensioning (PT) strand at failure. Previous research on industry-representative standard PT anchor components from the U.S. has shown t...
Territorial authorities in New Zealand are responding to regulatory and market forces in the wake of the 2011 Christchurch earthquake to assess and retrofit buildings determined to be particularly vulnerable to earthquakes. Pending legislation may shorten the permissible timeframes on such seismic improvement programmes, but Auckland Council’s Prop...
Following the 1931 Hawke’s Bay earthquake, buildings in Napier, Hastings, and surrounding areas were rebuilt in a comparatively homogenous structural and architectural style comprising the region’s famous Art Deco building stock. These ‘interwar buildings’ are most often composed of reinforced concrete frames and (while detailed in a fairly ductile...
Following the 1931 Hawke’s Bay earthquake, buildings in Napier and surrounding areas were rebuilt in a comparatively homogenous structural and architectural style comprising the region’s famous Art Deco stock. These ‘interwar buildings’ are most often composed of reinforced concrete frames and, while detailed in a fairly ductile fashion for the tim...
This paper presents an experimental investigation on the strand wire fracture stresses and strains in unbonded post-tensioning strand-anchorage systems subjected to a variety of loading conditions that can affect the performance of the strand inside the anchor. While unbonded post-tensioned gravity load systems (for example, floor and roof slabs) a...
This paper presents an experimental study on the ultimate behavior of unbonded post-tensioning monostrand anchorage systems under monotonic tensile loading. New types of seismic precast concrete structural systems using unbonded post-tensioning have emerged in recent years. While unbonded post-tensioned gravity systems (for example, floor and roof...