M. C. Griffith

University of Adelaide · School of Civil, Environmental & Mining Engineering

A coupled damage-plastic based constitutive model using a traction-separation law is developed in this study to simulate the behaviour of mortar joints in masonry structural panels subjected to in-plane (2D) and out-of-plane (3D) loading. A smooth hyperbolic failure surface is used to develop the interface material model, which is implemented numer...

For other than minor modifications or additions to existing masonry structures, an understanding of the in-situ mechanical properties of the masonry is required. Estimation of shear strength of the masonry bond is often made using the in-plane shove test as it only requires access from one side of the masonry being tested, and is therefore consider...

Failure of unreinforced masonry following the 2011 Christchurch earthquake demonstrated that many masonry strengthening solutions were inadequate for the peak ground accelerations that were experienced, and also that many of the failures were associated with underperformance of masonry anchors. Recent in-situ pull-out tests of anchors in vintage ma...

The rapid adoption of 3D-printing (3DP) technologies in construction, combined with an increased willingness to reduce environmental impact, has facilitated reapproaching earth materials for modern building industry. The feasibility of 3DP earth-based materials has been under investigation in recent years, with a particular focus on cob due to its...

The rapid adoption of 3D printing (3DP) technologies in construction, combined by an increased willingness to reduce the environmental impact of building industry, has facilitated reapproaching earth materials for modern building industry. The feasibility of 3DP earth-based materials has been under investigation for few years, with a particular foc...

In the experimental assessment of the in-plane behaviour of unreinforced masonry (URM) walls containing openings, accurate measurement of the deformations occurring in the pier and spandrel substructures is important. Eight full-scale perforated URM walls were tested under in-plane cyclic loading and constant vertical pre-compression load. To measu...

Investigations of damage sustained following the 2010–2011 Canterbury earthquake sequence highlighted premature failure of anchorages in previously strengthened masonry. These failures suggest that a lack of understanding surrounding anchorage design is limiting the ability to seismically retrofit masonry structures. In order to provide experimenta...

This paper presents the results of an experimental study into the behavior of perforated (containing openings) unreinforced masonry (URM) walls subjected to cyclic in-plane lateral loading. Damage to perforated URM walls during previous earthquakes has revealed that the in-plane response is mainly influenced by the pier and spandrel geometry, as we...

A formulation is presented for simplified evaluation of the roof acceleration response for the purpose of assessing non-structural components in unreinforced masonry buildings with flexible diaphragms excluding torsional effects. The method is based on modal calculations that are further studied through nonlinear time-history analysis (NLTHA) of fo...

This paper presents numerical modelling of the in-plane shear behaviour of unreinforced masonry (URM) walls with a semicircular arch opening. To do so, two dimensional finite element (FE) modelling of a series of experimentally tested walls was conducted using the simplified micro-modelling approach. The models successfully captured the load-displa...

Suitability of height amplification factors for seismic assessment of existing unreinforced masonry components", Journal of Earthquake Engineering, ABSTRACT The suitability of 'design' height amplification factors (HAF) for the purpose of seismic assessment of existing non-structural unreinforced masonry (URM) components with known strength was eva...

The present study was conducted to investigate the global and local in-plane response of perforated URM walls under earthquake loading, based on observations of damage from previous earthquakes. To do so, full-scale cyclic in-plane testing of URM walls with an arched opening which were designed to represent walls in heritage URM structures in Austr...

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,...

This study presents an experimental investigation of the effect of environmental exposure on the fibre-reinforced polymer (FRP) to clay brick masonry bond when the reinforcement is near-surface-mounted. Three alternate types of exposure are considered: (i) thermal loading with a single or multiple thermal exposure cycles, (ii) water immersion, and...

The use by practicing engineers of Fibre Reinforced Polymer (FRP) anchors in combination with Externally Bonded Reinforcements (EBR) is increasing. FRP anchors are typically used to prevent premature FRP-to-concrete debonding and/or to ensure the continuity of the load path from the FRP sheet into the concrete substrate. Recently proposed design mo...

Historical unreinforced masonry (URM) buildings in Australia are vulnerable to damage during earthquakes. This was highlighted by the 1989 Newcastle earthquake, which caused extensive damage in older URM construction, despite being of only moderate magnitude (M5.6). Based on the importance of the historical URM buildings, this study was conducted t...

The reliable prediction of strength and failure modes of perforated URM walls are important in the seismic assessment of URM buildings. These walls form part of the primary lateral load resisting system in URM buildings and have frequently suffered damage in previous earthquake events throughout the world. Due to the anisotropic characteristics of...

Historical unreinforced masonry (URM) buildings in Australia are vulnerable to damage during earthquakes. This was highlighted by the 1989 Newcastle earthquake, which caused extensive damage in older URM construction, despite being of only moderate magnitude (M5.6). Based on the importance of the historical URM buildings, this study was conducted t...

The strength and deformability of reinforced concrete (RC) structures strengthened with externally bonded fibre-reinforced polymer (FRP) composites can be enhanced with the addition of anchorage devices. The inclusion of anchorage can also result in a higher utilization of the desirable strength properties of the FRP by mitigating debonding. FRP sp...

In the general framework of seismic hazard analysis for quantifying site amplification, knowledge of the near surface shear wave velocity profile is crucial. The non-destructive and affordable ambient vibration array technique has been shown to be a superior method for estimating this shear wave velocity. The present study seeks to investigate the...

Accurately measured strains are critical when investigating the application of Fiber Reinforced Polymer (FRP) materials, but traditional mechanical strain measurement methods have several critical drawbacks related to the installation process and the recording capabilities of the devices. FRP materials typically used in the civil engineering field...

The implementation of Fiber Reinforced Polymer (FRP) anchors in Externally Bonded Fiber Reinforced Polymer (EBR-FRP) systems is an effective method to increase the bond strength and/or ensure the continuity of the load path between FRP materials and the concrete substrate when EBR-FRP systems are used to strengthen and/or repair existing structures...

This paper describes the preliminary results from the building survey work by the project team to document and classify the full inventory of unreinforced masonry (URM) buildings in the heritage listed township of York in West Australia. This Bushfire and Natural Hazards CRC project evolved out of the concerns of one of its end users, the WA Depart...

A three-year ARC funded research project featuring a collaboration between researchers at the University of Auckland in New Zealand and the Universities of Newcastle and Adelaide in Australia is now into its second year with some promising early results and exciting experimental tests to come in the near future. The overall aim of this project is t...

The main Anglican church in Adelaide, St Peter's Cathedral, is prominent on the city's skyline as it sits adjacent to the Adelaide oval and just across the Torrens river from the central business district. In late 2017, the church decided to undertake remedial work of its roof structure in order to stop water ingress problems through several leaks....

Methods for simulating the mechanics of debonding and predicting global load-slip (P-Δ) response from local bond stress versus slip (τ-δ) relationships can vary significantly in their complexity. It is generally accepted that an adequate representation of intermediate crack debonding can be achieved by considering only mode-II (shear) fracture alon...

The effectiveness of FRP retrofits is heavily reliant on the shear bond that can be developed between the FRP and masonry substrate, which has been the focus of experimental research for almost two decades. This paper collates and critically reviews previous experimental work on the shear bond between FRP composites and masonry substrates, identify...

The purpose of the work was to characterize the behavior of FRP anchors installed at the end of FRP sheets and develop a methodology to calculate the capacity when the anchors exhibited the fiber rupture failure mode. To do so an extensive experimental program was undertaken and the force transfer mechanism between the anchor and the structure was...

The data presented in this article contain datasets of passive noise measurements at regolith sites in Adelaide, South Australia. The data were acquired using 3 component (3C) LE-3Dlite Lennartz seismometers with an eigenfrequency of 1 Hz. The data were acquired at 8 sites across Adelaide’s regolith in a hexagonal array layout. Four tests, each wit...

The nature of urban development in New Zealand and Australia followed a similar pattern, with communities frequently having a high density of unreinforced masonry (URM) buildings at their civic centre due to the early colonial practice of repeating the style of building architecture that was fashionable in the United Kingdom during the mid and late...

Five half-scale unreinforced clay brick walls were subjected to out-of-plane shaketable testing, in order to verify whether wall behaviour observed in a previous test campaign involving quasistatic cyclic loading of full-scale walls could be considered representative under dynamic loading. The walls tested in the present study all had identical dim...

Existing reinforced concrete structures are frequently deemed to be prone to severe damage and/or collapse as a result of the loads that the structure is expected to experience if it were to be subjected to large intensity earthquake shaking. Among the different approaches to elevate the seismic capacity of existing reinforced concrete structures i...

Subsurface geometry, particularly the depth of bedrock, is crucial in seismic hazard studies because the basin geometry has been shown to play an important role in the altering of seismic waves. Estimating the bedrock surface using ambient seismic noise analysis has been undertaken by many researchers, with most studies focusing on sites with a str...

https://www.youtube.com/watch?v=ZkqKHgNQgM8

An experimental campaign consisting of nine pressure-controlled quasi-static airbag tests on unreinforced masonry (URM) walls and accompanying material testing was completed to investigate methods for seismic retrofit of out-of-plane loaded cavity walls. Three control walls were tested to serve as a baseline for wall strength comparisons: (1) a dou...

Three major seismic events have damaged the Old Exchange Building, Adelaide, southern Australia. The building was graced by the Britannia statue on the parapet of the building. The statue lost its arm during the 1897 Beachport earthquake and bowed its helmeted head during the 1902 Warooka seismic event. It was removed after the 1954 Adelaide earthq...

Failure of domestic unreinforced masonry (URM) chimneys was the first and most frequently encountered evidence of damage observed immediately following the 14 November 2016 Kaikoura earthquake, and previous earthquakes in New Zealand and around the world. The damage typically observed involves the cantilever part of a URM chimney above the roofline...

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...

Masonry is a composite material with highly variable and relatively uncertain anisotropic mechanical properties. In contrast to other construction materials such as reinforced concrete and steel, common modelling approaches are not fully applicable to unreinforced masonry (URM) buildings, and serious mistakes can easily be made if practitioners lac...

Heritage URM buildings represent the history, culture and identity of our towns and cities making them important assets to retain and preserve. However, they are vulnerable to damage during earthquakes. This vulnerability arises firstly from the building class to which they belong; unreinforced masonry, which performs poorly during earthquake shaki...

Similar unreinforced masonry (URM) buildings are found in Australia and New Zealand due to the two countries’ shared history of European settlement. It is known that there is a large inventory of URM buildings in both countries and that these buildings are potentially earthquake prone. Therefore, an understanding of their behaviour when subjected t...

Professor Griffith will give an overview of recent and ongoing research into the seismic behaviour of unreinforced masonry (URM) construction in Australia. His talk will focus primarily on: * the seismic vulnerability of URM walls to out-of-plane bending and the associated local failure mechanisms; * the influence of flexible floor and roof diaphr...

An experimental programme was developed to improve our understanding of the actual in situ strength of non-structural components in typical South Australian unreinforced masonry (URM) construction. The focus was on testing URM walls and chimneys in out-of-plane direction, and in the course of this study 132 as-built URM material specimens were coll...

The use of Externally Bonded Fibre Reinforced Polymer (EBR-FRP) systems is an established technique for the structural improvement of existing buildings but the technique features disadvantages. Premature FRP-to-concrete debonding has been commonly highlighted as one of the main problems, together with the difficulty of fully wrapping the structura...

An in-situ unreinforced masonry (URM) wall testing programme was conducted to study the effects of as-built wall boundary conditions on its out-of-plane strength. In total, eight pressure-controlled quasi-static airbag tests were done on 4 double-leaf cavity walls and 4 single-leaf solid walls, followed by relevant material testing. The walls were...

The use of Externally Bonded Fiber Reinforced Polymer (EBR-FRP) systems is an established technique for the structural improvement of existing buildings but the technique features disadvantages. Premature FRP-to-concrete debonding has been commonly highlighted as one of the main problems, together with the difficulty of fully wrapping the structura...

Anchorage devices can enhance the strength and deformability of reinforced concrete (RC) structures strengthened with fiber-reinforced polymer (FRP) materials. Anchorage can also result in a higher utilization of the desirable strength properties of the FRP. FRP anchors are commonly used in practice as such anchors are particularly well-suited to a...

Seismic site classification is the most widely accepted practical method in the design of seismic resistant infrastructure. The horizontal vertical spectral ratio (HVSR) technique for analyzing ambient noise data has been successfully applied to quantify site effects in the estimation of seismic site classes associated with seismic hazards. This su...

An experimental campaign was developed to evaluate the response of non-structural elements of unreinforced masonry buildings for simulated earthquake loads. Eleven walls within 4 URM properties were subjected, in-situ, to uniformly distributed static loads applied using a system of airbags. The buildings were located in Darlington, a suburb of Adel...

This paper presents a numerical investigation into the behaviour of unreinforced clay brick masonry walls with window and door type openings, subjected to in-plane loads. Nonlinear finite element simulations of full scale walls experimentally tested at The University of Newcastle have been undertaken using the commercial finite element analysis sof...

This paper describes a methodology for modelling the nonlinear, inelastic load?displacement behaviour of two-way spanning unreinforced masonry walls subjected to out-of-plane loading. The model utilises a simplified macroblock approach that starts with the assumption of a collapse mechanism based on the wall's boundary conditions. It then treats th...

The development of standard analytical procedures and design guidelines for concrete requires extensive tests at material and structural level. For ultra-high performance fibre reinforced concrete (UHPFRC) this task is even more complicated than that of conventional concrete due to the potential range of fibre types and volume fractions. The experi...

Unreinforced masonry walls subjected to out-of-plane horizontal bending can fail by two alternate modes: stepped failure along the brick-mortar bond, or line failure cutting directly through the bricks. Because of random variations in material properties throughout a panel and the tendency for failure to occur across the weaker elements, vertical c...

The applicability of the N2 method, the modal pushover analysis (MPA) and an adaptive pushover analysis method are investigated for estimating the peak seismic responses of unreinforced masonry buildings with flexible diaphragms. The performance of nonlinear static procedures are compared against the nonlinear time-history analyses of three low-ris...

It is natural to extend conventional unimodal optimization to challenging multimodal optimization design of composite structures by means of emergent niching particle swarm optimization (PSO), due to multimodal characteristics of composite structures by nature. The advanced multimodal PSO algorithms adopted in the present study include the species-...

Static and vibration characteristics of thin-walled straight and curved box beams were investigated experimentally. Three different beam configurations were considered for the tests: one straight and two curved box beams. The load was applied at the centroid of the box section for the straight and one curved beam specimens. However, for the other c...

The use of Fibre Reinforced Polymer (FRP) materials as Externally Bonded Reinforcements (EBR) is an established technique for structural improvement of existing buildings. Nevertheless the technique features disadvantages, and premature FRP-to-concrete debonding has been commonly highlighted as one of the main problems, together with the difficulty...

Earthquakes cause severe damage to masonry structures due to inertial forces acting in the normal direction to the plane of the walls. The out-of-plane behavior of masonry walls is complex and depends on several parameters, such as material and geometric properties of walls, connections between structural elements, the characteristics of the input...

A case study was conducted to investigate the applicability of equivalent frame modelling for the nonlinear time-history analysis of unreinforced masonry buildings with flexible diaphragms. The dynamic responses calculated from the equivalent frame models were compared against shake table test results of a full-scale two-storey stone masonry buildi...

Significant research has been conducted to establish the seismic capacity of unreinforced clay brick masonry buildings in Australia. In this paper, we consider modern and older existing construction typical of Australia. The paper presents results of laboratory tests on large scale walls, in-situ tests of walls in houses, and analytical predictions...

Numerous low to moderate magnitude earthquakes have been recorded across the state of New South Wales (NSW) since European settlement in 1788. Of these, significant damage was caused by the moderate M5.6 Newcastle earthquake in December 1989, causing the deaths of 13 people and extensive damage to unreinforced masonry (URM) buildings. The majority...

Array ambient noise measurement is a useful method to obtain the dynamic characteristics of near-surface geology. The method is advantageous for site seismic investigation in urban areas, largely as a result of improvements in the signal-to-noise ratio (SNR) due to the summation of the individual recordings of the array stations. This technique ena...

The efficiency of externally bonded fibre reinforced polymer reinforcement to strengthen or repair existing reinforced concrete structures is compromised due to the difficulty in achieving the full strength of FRP sheets prior to debonding of the sheet from the substrate. Straight FRP anchors feature a number of advantages to solve this problem, bu...

The main problem when strengthening existing reinforced concrete structures using externally bonded fibre reinforced polymers is premature FRP-to-concrete debonding. Bent FRP anchors were introduced as a solution to improve the FRP-to-concrete bond strength, but incomplete information on anchor behaviour and the absence of reliable design equations...

A displacement-based (DB) assessment procedure was used to predict the results of shake table testing of two unreinforced masonry buildings, one made of clay bricks and the other of stone masonry. The simple buildings were subject to an acceleration history, with the maximum acceleration incrementally increased until a collapse mechanism formed. Us...

Observations after strong earthquakes show that out-of-plane failure of unreinforced masonry elements probably constitutes the most serious life-safety hazard for this type of construction. Existing unreinforced masonry buildings tend to be more vulnerable than new buildings, not only because they have been designed to little or no seismic loading...

A case study was conducted to investigate the applicability of the equivalent frame modelling for the nonlinear time-history analysis of unreinforced masonry buildings with flexible diaphragms. The dynamic responses calculated from the equivalent frame models were compared against shake table test results of a full-scale two-storey stone masonry bu...

The effects of diaphragm flexibility on the seismic response of low-rise unreinforced masonry buildings are examined using one-way stiffness- and strength-eccentric single-storey systems subjected to unidirectional ground excitation. A wide range of diaphragm stiffnesses are considered. Results show that diaphragm flexibility can induce different e...

On 25 April 2015 at 11:56 local time a moment magnitude (M w) 7.8 earthquake struck Nepal, with the epicentre in Gorkha District (northwest) of Kathmandu and south of the China border. More than 390 aftershocks followed with magnitude 4 or higher, including a magnitude 6.7 and a 7.3 earthquake on 26 April and 12 May 2015, respectively. The epicentr...

Ultra-high performance concrete (UHPC) which is characterised by high strength and, when reinforced with steel fibres, high ductility, has the potential to revolutionise the construction industry. The application of UHPC is currently mainly limited to landmark projects due to the high cost of manufacture, which often involve specialist materials su...

A novel analysis technique is introduced for efficient modelling of box girder bridge decks. The general three-dimensional equations used to accurately define the deformation of these complex beam-like slender structures are decoupled into a two-dimensional cross-sectional problem and a one-dimensional beam problem through decomposition of the thre...

Out-of-plane bending tests were conducted to determine whether rammed earth (RE) walls, designed to satisfy the thermal performance requirements specified by the Building Code of Australia, will satisfy the seismic loading requirements. A 2.4 m tall by 1.2 m wide full-scale insulated RE wall comprised of two 175 mm thick leaves separated by a 50-mm...

Structural strengthening using externally bonded fibre reinforced polymer (FRP) materials is an established method to enhance the performance of existing structures. Although standardised design methods are available for the strengthening of simple elements, limited guidance is available to apply these designs to the complex geometries which are co...

The application of the horizontal vertical spectral ratio (HVSR) technique using microtremor measurement to quantify the natural period of sites in urban areas is widely used around the world. However, this technique is still under development in regions with low impedance contrast between the top layer and the underlying bedrock, such as regolith....

A simplified numerical model was used to investigate the out-of-plane seismic response of vertically spanning unreinforced masonry (URM) wall strips. The URM wall strips were assumed to span between two flexible diaphragms and to develop a horizontal crack above the wall mid-height. Three degrees of freedom were used to accommodate the wall displac...

The single microtremor method has been applied to Adelaide's regolith which exhibits low impedance contrast between the upper and bedrock layers. Preliminary findings show that the predominant fundamental period is between 0.8 and 3.0 seconds. This suggests greatly amplified ground motions for 3 to 5 storey buildings in the Adelaide City due to fut...

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...

For the prediction of buckling response of grid stiffened composite panels having different stiffening arrangements, an efficient finite element modelling technique is presented. The laminated skin of the stiffened structure is modelled with a triangular degenerated curved shell element. An efficient curved beam element compatible with the shell el...

As part of a seismic retrofit scheme, surface bonded glass fiber-reinforced polymer (GFRP) fabric was applied to two unreinforced masonry (URM) buildings located in Christchurch, New Zealand. The unreinforced stone masonry of Christchurch Girls’ High School (GHS) and the unreinforced clay brick masonry Shirley Community Centre were retrofitted usin...