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Structural frames infilled with masonry material called masonry-infilled frames (MIFs) are common types of constructions around the world. These structures generally have mortared masonry as infill material which made the buildings stiff during past earthquakes and generated additional torsional forces. With a view to improve the seismic performance of MIFs this paper presents the results of a numerical simulation study on the behaviour of previously-tested MIFs with semi-interlocking masonry (SIM) material. In a simplified micro-modelling approach, the concrete and masonry materials are simulated using Concrete Damaged Plasticity technique and the joints are considered as zero-thickness cohesive interfaces modelled using traction-separation model. The numerical model is then used to study the lateral load response of the alternate MIF with SIM. The methodology for FE modelling of MIFs with SIM as an infill material is developed and explained in detail. The numerical models incorporate the sliding of the masonry units under the application of lateral loads. It is shown that the models capture the experimental results quite well although the modelling technique has certain limitations. The outcomes of a sensitivity analysis on the effects of the interface mechanical properties are presented along with discussion of limitations and suggestions for future improvements.

Masonry construction is popular around the world, but the use of mortared masonry presents numerous challenges. In recent decades, masonry construction systems incorporating interlocking masonry units have been proposed to eliminate mortar. The interlocking between masonry units can be achieved using specially shaped units. This paper presents a comprehensive experimental study to determine the behaviour as well as basic material properties of one such semi-interlocking mortarless masonry. The experiments included testings of ungrouted masonry units, prisms, and wallets. In addition, masonry prisms and wallets with grouted cores were also investigated to study the effect of grouting. A detailed description of the construction procedure is explained. The failure mechanisms, maximum strengths, force–displacement relationships, and modulus of elasticity of the samples are obtained and contrasted with the relevant results from the literature. Finally, recommendations are made that may assist material model development required for micro- and macro-modelling of mortarless masonry. The new information generated in this research will enable better understanding of the behaviour and properties of semi-interlocking mortarless masonry and will be useful for validating numerical models in future research.

Worldwide, unreinforced masonry (URM) buildings are present in abundance with many holding cultural and heritage value. URM buildings have a known history of poor performance during past earthquakes because of the weak tensile properties and lack of mechanical connections between elements. Information about the construction of URM buildings for a region is important because it can help engineers and policy makers to perform seismic assessment, risk and loss studies. In this regard, this study includes a characterisation of the heritage URM buildings in Brisbane City, Australia, and its surrounding suburbs using the Queensland Heritage Register (QHR). The QHR includes a total of 1775 heritage sites, of which 323 are identified as URM buildings in Brisbane City and surrounding suburbs. The studied building characteristics obtained from QHR included the architectural styles, construction year, function/use, number of storeys, roof material and load-bearing wall materials. Other features such as roof types (shapes), plan geometry, isolated or interconnected buildings, verandas and openings, and finally the presence of seismic hazards such as gable-end walls, chimneys, and parapets have been obtained using online 3D maps. It was concluded that heritage registers in combination with online digital resources can be successfully utilised to characterise URM buildings.

Masonry-infilled frames (MIFs) are a common construction form in many parts of the world. The presence of mortared masonry makes structural frames relatively stiff resulting in limited displacement capacity and unintended torsional forces that have been responsible for catastrophic destruction of buildings during several past seismic events. An alternative infill material solution is using semi-interlocking (mortarless) masonry (SIM), which is associated with controlled in-plane sliding. Five small-dimensioned specimens, including one bare frame and four SIM-infilled concrete frames were constructed and subjected to cyclic displacements. The variable parameters included specimen aspect ratio, vertical load on frame members, and grouting of masonry. A detailed description of the construction procedure and the testing of material properties used in the experiments are presented. The damage patterns associated to each of the specimens are explained to investigate their deformation modes and to identify the drift thresholds corresponding to the damage in the MIFs. A modified idealisation model is proposed that is suitable for SIM-infilled reinforced concrete MIFs. Critical structural properties of MIFs that include the yield strength, energy dissipation capacity, initial stiffness and ductility are obtained from the idealisation model and the force-displacement relationship. These properties are compared and contrasted against the specimens and also to the traditional MIFs with the relevant data extracted from literature. From the observed damage and the force-displacement relationship, Performance Levels of the MIFs are established. Compared to traditional MIFs, the SIM-infilled MIFs are shown to have significantly smaller initial stiffness and larger performance level drift thresholds.

Characterisation of buildings is critical for the rapid assessment and seismic loss estimation of buildings after an earthquake event. This paper presents a literature review on the characterisation of unreinforced masonry (URM) buildings followed by a typological study of the building stock in Queensland, Australia. The literature review showed that characterisation studies are aimed at cataloguing and developing inventories of buildings for the purpose of seismic vulnerability and risk assessment, and behaviour-influencing parameters are often used as a basis for building classification. Guided by the literature review, a field study was conducted to document important features of vintage (pre-1940) URM buildings that can influence their behaviour during an earthquake. The surveyed aspects included the construction year, number of storeys, roof type, irregularities in plan, isolated or inter-connected buildings, overall dimensions of the buildings, size and shape of windows, façade opening ratio, presence of chimneys, and the style of parapets. Importantly, it was found that certain parapet typologies are prevalent, but that their seismic behaviour is currently unknown. A few such typologies were recommended for future seismic assessment studies. This study can serve as a basis for conducting seismic assessment risk and vulnerability studies in the future.

Fiber-reinforced polymer (FRP) composite materials have gained popularity in civil, mechanical, aircraft, and chemical engineering domains due to their superior mechanical properties and durability. They have been used for strength and durability enhancements of civil structures and a wide range of steel structures subject to static (flexure, compression) and dynamic (fatigue, impact, and seismic) loads have been strengthened and retrofitted. The strength enhancement provided by FRP composites to steel structures depends on several parameters including fiber types, fiber orientations, number of fiber layers, steel section types (geometry and grade), member slenderness etc. Although the superior properties of FRP are sometimes affected by severe environmental conditions that the structures are exposed to, these adverse effects can be minimized. This paper provides a comprehensive review of various techniques to improve the performance and design of steel structures using FRP composites. Strength prediction models under a range of loading and environmental conditions are presented in this single document for the evaluation and safe design of FRP strengthened steel structures and thereby minimise their vulnerability to failure

This paper summarises the development of a state-of-art impact testing machine for simulating impacts such as vehicular crashes or debris impacts onto structures. The machine has a 200 kg pneumatically powered projectile which can travel horizontally within the barrel of the machine with a maximum velocity of 50 m/s to impact the target structure. The maximum kinetic energy that can be generated by the projectile is 125 kJ by using different combinations of mass and velocity. The diameter of the projectile is 214 mm, and its impacting face can be changed to different shapes, such as flat circle, flat square or an elliptical nose to suit different impact scenarios. An innovative braking mechanism incorporating a crush tube is attached within the barrel to ensure safety when the projectile fails to be restrained by the impact. The crush tube can absorb the maximum imparted by the moving projectile. An advanced data acquisition system is installed to collect quantitative and qualitative test data during a period of 50 ms to 1 s. Two high-speed digital image correlation (DIC) cameras are attached and synchronised with the operation of the impact testing machine to record the images at the rate of 50,000 frames per second. Outputs in terms of strains, deformations, accelerations of the target structure with a record of damage history can be analysed using this 3D DIC technique. The paper also briefly presents the first application of this machine for impact testing masonry wall structures.

Auxetic materials, possessing negative Poisson’s ratios (NPRs), have the ability to shrink (or expand) in the lateral direction under an axial compressive (or tensile) force respectively. Due to this unique feature, an auxetic material is found to sustain high energy absorption capacity, fracture toughness and shear resistance and thus regarded as one of the future materials in the field of impact protection. However, civil engineering applications of auxetic structures or materials are minimal due to miscellaneous restrictions on NPR effects. Accumulative developments in auxetics have facilitated their applications in cementitious materials in recent years. This paper presents an overview of recent advances in the development of auxetic cementitious composites and analyses and summarises their mechanical properties under different loading conditions. Prior to extensive finite element simulations, more attention has been given to the limited experimental results. Particular attention is paid to the expansionary feasibility of the parent material to introduce auxetic behaviour, with precise identification of the limitations, innovative composition methods and facilitation of auxetic features. Finally, the paper outlines the limitations of the current research and envisages few future research opportunities in auxetic cementitious composites.

Square hollow section (SHS) beam–column connections are prevalent in steel structures and extensively used in high seismic risk regions due to their significant architectural and structural benefits. Rehabilitation and strengthening of SHS connections are important considerations due to the vulnerable effects of cyclic loading. Studies on the structural performance of CFRP strengthened SHS connections under large displacement cyclic loading are, however, very limited and the finite element (FE) modelling numerical approach not yet been developed. The objective of the current research is to develop a FE modelling numerical approach to simulate the cyclic response of CFRP strengthened SHS beam–column connections. The modelling techniques are validated by comparing the FE model simulated results with the authors’ experimental results. A detailed parametric study is then conducted to study the effects of the thickness of the beam and column section, moment arm, and the strengthening scheme on the cyclic performance of CFRP strengthened SHS beam–column connections. CFRP strengthened SHS beam–column connections have shown improvements in structural performance with respect to moment hysteresis response, stiffness and energy dissipation capacity. Moreover, CFRP strengthened connections showed less tendency for buckling compared to their bare counterparts. Research findings of the present study will be beneficial to restore the structural integrity of SHS beam–column connections through CFRP strengthening.

Track thermal buckling is one of the primary safety issues of continuously welded rail tracks. It has been shown that transition zones of open deck steel bridges are more prone to track buckling, as the thermal loads from the bridge and lower track lateral resistance in this region can destabilize the track in the lateral plane. The aim of this paper is to assess the possibility of reinforcing the ballast layer with geotextiles to mitigate the track buckling problem in the transition zones. To do so, a number of laboratory experiments are performed using one and two layers of geogrids and various depths of ballast layer. Single tie push tests are performed on the track and force-displacement curves are derived for the sleepers. It is shown that adding the geotextile layer to the ballast layer can increase its lateral resistance by up to 41%. The results are then introduced in the numerical model of a track developed in Abaqus finite element software for track buckling analysis. It is shown that adding the geogrid layer can increase the track buckling temperature by up to 11.33 °C, an increase of almost 21%, compared to that of an unreinforced track.

Hyperbolic cooling towers are large thin shell reinforced concrete structures that are used to remove the heat from wastewater and transfer it to the atmosphere using the process of evaporation. During its long service life, a cooling tower can experience damage due to the large temperature variations, environmental degradation, or random actions such as impacts or earthquakes. Such a damage can develop over time and result in the sudden collapse of the cooling tower. To ensure that a cooling tower operates safely and efficiently at all times, it is important to monitor its structural health. In this context, structural health monitoring based on the vibration characteristics of the structure, has emerged as a useful method to detect and locate damage in structures. Hyperbolic cooling towers, due to their particular shape, exhibit rather complex vibration characteristics that do not suit the traditional vibration-based damage detection techniques. This paper develops and applies a damage assessment method using the absolute changes in mode shape curvature (ACMSC) in conjunction with Artificial Neural Networks (ANNs) to detect, locate, and quantify damage in hyperbolic cooling towers. ANN is a machine learning technique that can predict behavioural patterns using a set of data samples and finds use in the damage quantification process. The proposed method for detecting and locating damage is experimentally validated and demonstrated its capability to accurately detect and locate damage. A feed-forward network having one hidden layer with Bayesian algorithm is used to train the artificial neural network. Damage indices calculated from noise polluted mode shape data are used to train the network. The trained network is then used to successfully assess the unknown damage severities in the cooling tower. The outcomes of this paper will enable early warning of damages in the cooling towers and will help towards their safe operation.

Past research has indicated that the effects of impact loads due to hard aircraft landings are critical to be considered in the design of runway pavements. However, the current Australian Standard only considers the gravity load of the landed aircraft. Based on the literature it is evident that very limited research has been conducted to understand the performance of conventional runway pavements under impact loading. This paper carries out a comprehensive experimental investigation on the impact response of four types of runway pavements with different compositions. Two are conventional runway pavements and the other two runway pavements have varied compositions to enhance performance under impact loads. The effects of controlling parameters are captured and then used to evaluate the safety and performance of the runway pavements under dynamic impact loads. Experimental results show that the incorporation of high strength concrete in the base layer of the flexible pavement and plastic fibers into the concrete pavement can significantly improve the impact resistance of the two different (conventional) runway pavement systems. The enhanced performance of the runway pavements is captured through the deflection time history, energy absorption and failure mode. These research findings will inform the design of runway pavements for enhanced protective performance.

Most international masonry design standards include the contribution of reinforcements to enhance the capacity of reinforced masonry walls subject to seismic loading. As masonry is brittle, it can potentially fail before the reinforcing bars yield, especially in closely spaced reinforced masonry walls. The assumption that these bars yield at the ultimate load could, therefore, result in an unrealistic over-prediction of the flexural and shear capacities of the walls. This paper presents a detailed investigation of several fully grouted reinforced masonry (FGRM) walls subject to in-plane and out-of-plane loading that is independent of each other. The analyses include the level of pre-compression and a wide range of reinforcement ratios. The assessment has been carried out through an explicit finite element (FE) model. Validation of the FE model is briefly presented and the structural performance, i.e., load capacity, lateral drift index, displacement ductility and stiffness of the FGRM walls are discussed in detail. The influence of reinforcement ratio on the yielding of reinforcing bars in the FGRM walls under in-plane and out-of-plane loading is also shown. It is found that the increase in reinforcement ratio beyond a critical limit degraded the structural performance of the FGRM walls and a suitable reinforcement ratio range is proposed.

Circular hollow steel (CHS) members have been regarded as structural elements of choice for use in civil infrastructure. Despite the risk of seismic damage of steel structures during an earthquake due to its cyclic characteristics, studies on the cyclic strengthening of CHSs have been minimal. In the present study, a new finite element (FE) modelling approach is developed and applied to study the cyclic performance of carbon fibre reinforced polymer (CFRP) strengthened CHS specimens. The modelling techniques are first validated using results from the authors’ previous experimental work. A detailed parametric study is then carried out to evaluate the effects of CFRP bond length, CFRP layer numbers, ratio of thickness of CFRP to thickness of CHS, CHS member diameter-to-thickness ratio and steel grade on the cyclic performance of the CFRP strengthened CHS members. Results confirm the significant effects of these parameters on the cyclic performance of CFRP strengthened CHS members. The efficiency of CFRP strengthening increases with an increase in the ratio of the thickness of CFRP to the thickness of CHS and also with an increase in the diameter-to-thickness ratio of CHS specimens. Conversely, the efficiency of CFRP strengthening reduces with an increase in the steel grade. Moreover, the ultimate moment capacities obtained from the FE analyses of the bare and CFRP strengthened CHS specimens agree reasonably well with the theoretically predicted values.

Most masonry arch railway bridges in the world are servicing the communities well beyond their intended design lives. However, these bridges would have undergone numerous deteriorations over the period of several decades of service life. The asset owners of these bridges are confronted with the decision over whether to continue servicing or decommissioning these bridges. Such decisions are critical from safety and economic points of views, and it can be addressed only by conducting a proper investigation of such structures. This paper presents the capacity assessment of typical in-service masonry arch bridges based on properties of masonry obtained through core testing. The bridges were modeled and analyzed for the ultimate capacity through limit state analysis method. Important parameters such as influence of backfill properties, strength of masonry, and span-to-rise ratio are discussed. The results indicate that the investigated bridges can sustain the current operating loads with a reasonable margin of safety index.

This paper reviews the approach of eleven national codes on the analysis and design of masonry-infilled frames. It is shown that, in general, codes can be divided into two groups. The first group isolates the masonry and frame members by providing gaps to minimize the interaction between them. This method ensures that the complexities involved in analyzing the structure is avoided. However, the width of the gaps recommended is different for each of the codes. The second group takes advantage of the presence of high stiffness and strength masonry infill. In this technique, an equivalent-strut modeling strategy is mostly recommended. It is shown that the strut model suggested in each of the codes is different. An attempt to obtain a generic model for masonry-infilled frame failed largely due to the existence of many behavior-influencing parameters. Finally, it is suggested to have a paradigm shift in the modeling strategy where the masonry-infilled frames are classified into different categories and a model is suggested for each of them.

This paper presents a review of the literature on masonry-infilled frame structures subjected to lateral loads. A database of 167 experimental studies on the parameters that influence the response of masonry infill are first discussed. It is shown that there are far too many geometrical and material parameters that affect the behaviour and that the experimental results are not consistent. Masonry infill is in general analysed using an equivalent strut modelling method, which is also briefly described. It is demonstrated that despite rigorous studies across many years, researchers have not been able to find a generic model. Finally, finite element concepts introduced by different researchers are discussed which confirm that further research is required to obtain realistic structural performance of masonry-infilled frames. A future research direction is also provided.

Advances in structural engineering and material technology have resulted in increasing use of suspension bridges in infrastructure systems to satisfy the modern transportation requirements. However, during the long life of a suspension bridge, its main cables and hangers could suffer severe corrosion and fatigue leading to failure of at least a part of the bridge. There is a need for a simple and reliable procedure to detect and locate such damage at its onset so that appropriate retrofitting can be carried out to prevent the failure of these important structural elements. Current Structural Health Monitoring (SHM) systems are integrated with a variety of damage detection methods, which are global and local in nature. Limitations in local methods necessitate the non-destructive and global techniques for damage diagnosis leading to continuous development in vibration based damage detection (VBDD) methods. In this context, this paper develops and applies mode shape component specific damage indices namely; vertical damage index (DIV) and lateral damage index (DIL) based on the Modal Flexibility (MF) concept to detect and locate damage in the main cables and hangers of a suspension bridge. The application of these damage indices is illustrated under single, multiple and complex damage scenarios. Effects of noise in the modal data and higher order vibration modes on the damage detection capability are also captured. Results confirm the applicability of the proposed vertical damage index DIV to accurately detect damage in real suspension bridges using only the first few modes. Bridge engineers can use the proposed technique to monitor the health of suspension bridges and prevent their unexpected failure.

The results of an investigation of the probability of earthquake damage to nonstructural 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, in situ data on material strength, and simplified mechanical models. Uncertainties in capacity and demand were quantified based on, respectively, stochastic and deterministic approaches. The damage probabilities were compared with relevant guidelines and empirical damage data from three earthquakes. The study established a link between the qualitative damage states reported in existing guidelines and the quantitative URM component damage states. While some median damage state thresholds correlated well with the data from the guidelines, a larger dispersion value was found in the current study due to the large variations in component properties. Comparisons with empirical data suggest that the developed fragility data provide a realistic estimate of nonstructural component damage that occurred in similar buildings, with a reasonable level of conservatism. The outcome is useful in rapid assessment of the seismic risks due to nonstructural component collapse in URM precincts.

This paper presents a review of the literature on masonry-infilled frame structures subjected to lateral loads. A database of 167 experimental studies on the parameters that influence the response of masonry infill are first discussed. It is shown that there are far too many geometrical and material parameters that affect the behaviour and that the experimental results are not consistent. Masonry infill is in general analysed using an equivalent strut modelling method, which is also briefly described. It is demonstrated that despite rigorous studies across many years, researchers have not been able to find a generic model. Finally, finite element concepts introduced by different researchers are discussed which confirm that further research is required to obtain realistic structural performance of masonry-infilled frames. A future research direction is also provided.

Damage identification for complex structures is a challenging task due to the large amount of structural elements, limited number of measured modes and uncertainties in referenced numerical models. This article presents a study on enhancing the effectiveness of modal characteristics correlation methods for damage identification of complex structures. First, a correlation method using change in the ratio of modal strain energy to eigenvalue is introduced. Damage information is determined via a forward approach by optimizing the correlation level between the patterns of the analytical and measured changes in the ratio of modal strain energy to eigenvalue. Different from traditional optimization-based forward methods that require accurate numerical models, damage sensitivity coefficients of the ratio of modal strain energy to eigenvalue are directly estimated from the experimental modal information. To enhance the damage identification capability, both the elemental modal strain energy–eigenvalue ratio and the total modal strain energy–eigenvalue ratio components are examined in the correlation function. Second, a sensitivity-weighted search space scheme incorporated with genetic algorithm is developed to overcome the ill-posed problem that causes false detection errors. Finally, the correlation method and the enhanced technique are experimentally tested on a complex truss model with nearly 100 elements. To deal with the huge number of degrees of freedom in this structure, a multi-layout roving test with the adoption of redundant channels is designed, and a three-criterion strategy is used for the selection of modes. Results demonstrate the effectiveness of the proposed damage assessment framework to locate and estimate damage in complex truss structures.

Fiber Bragg grating (FBG) accelerometers using transverse forces are very sensitive. When a transverse force is applied to a lightly stretched string fixed by its two ends, a much stronger axial force along the string will be induced. So, the transverse force is amplified and converted into the axial force. At a given pre-strain of the string, the maximum amplification and requirements to obtain it have not been clearly demonstrated. Here, we theoretically prove and experimentally verify that the maximum amplification occurs when the strain induced by the transverse force approximately equals the pre-strain. This revelation improves the understanding of FBG accelerometers using transverse forces.

In recent years, it has become increasingly important to develop methodologies for reliable deterioration assessment of civil structures over their life cycle to facilitate maintenance and/or rehabilitation planning processes. Several approaches have been established to address this issue mainly using Bayesian probabilistic model updating techniques with some capability to incorporate uncertainties in the updating process. However, Bayesian model updating techniques are often found to be complex and computationally inefficient as opposed to their deterministic counterparts such as conventional or hybrid techniques of sensitivity-based model updating. Nevertheless, the deterministic model updating techniques have not been well developed for sophisticated assessment applications such as deterioration evaluation. To address these issues, this article presents a novel methodology for deterioration assessment of building structures under serviceability loading conditions, based upon an improved hybrid model updating approach incorporating the use of long-term monitoring data. This is first realized by a simple but effective scheme to simulate the deterioration mechanism in serviceability loading conditions before enhanced with innovative solutions to classify structural elements as well as to handle measurement and updating uncertainties in a meaningful way. The effectiveness of the established methodology is illustrated through a benchmark 10-story reinforced concrete building which is equipped with a long-term structural health monitoring system.

A Raise Crossing (RC) was suggested to prevent rail-road level crossing from severe accidents. In order to study its effect on the driver’s comfort in multi-direction, a five axle articulated truck was modelled three dimensionally using Multi-body dynamics method. The tractor had a cab with a driver inside and the trailer had two axles. The tire was represented using Flexible Structure Tire Model. Three kinds of curved road were studied to compare their effect on the driver’s comfort. The RC was particularly studied for its road radius, raised height and slope at different driving speed. It showed that lateral acceleration on RC was more than twice of it on SR; for a RC road, when the height of RC or the slope was higher, the driver had to reduce the vehicle’s speed to drive comfortably.

Concrete Filled Steel Tube (CFST) columns are popular in high rise buildings due to their superior strength, seismic and fire resistance capacities and construction simplicity. Structural framing systems in high rise buildings are commonly coupled with reinforced concrete outrigger and belt systems to facilitate lateral load resistance. When axial shortenings of vertical elements occur due to time dependent phenomena of creep, shrinkage and elastic deformations, the horizontal stiff elements balance the shortening differentials in the vertical elements and cause load redistributing among them dynamically. This can result in high transfer stresses induced in the stiff outrigger and belt systems which need to be considered in design or mitigated during construction. To plan mitigation strategies such as the time to connect the shear core to the structural frame to effectively reduce time dependent transfer stresses, it is necessary to quantify current and future differential axial shortenings. This paper first quantifies the differential axial shortening (DAS) between the shear core and columns, considering effects of construction sequence, time dependent material properties and reinforcement and then quantifies the transfer stresses built up in outrigger and belt systems in CFST high rise buildings. This information will be useful in mitigating the adverse effects of these high transfer stresses.

Fast computers and sophisticated numerical methods along with sound mathematical models have enabled structural health monitoring to emerge as an efficient means of evaluating the health of a structure and detect any damage to enable appropriate retrofitting. This paper uses vibration based methods to develop and apply techniques to detect the damage in beam and plate structures that form important components in buildings and bridges. The success of this technique will enhance the safety and efficiency of structures and prevent their unexpected and sudden collapse.

Portable water-filled road barriers (PWFB) are roadside structures placed on temporary construction zones to separate work site from moving traffic. Recent changes in governing standards require PWFB to adhere to strict compliance in terms of lateral displacement of the road barriers and vehicle redirectionality. Actual road safety barrier test can be very costly, thus researchers resort to Finite Element Analysis (FEA) in the initial designs phase prior to real vehicle test. There has been many research conducted on concrete barriers and flexible steel barriers using FEA, however not many is done pertaining to PWFB. This research probes a new method to model joint mechanism in PWFB. Two methods to model the joining mechanism are presented and discussed in relation to its practicality and accuracy to real work applications. Moreover, the study of the physical gap and mass of the barrier was investigated. Outcome from this research will benefit PWFB research and allow road barrier designers better knowledge in developing the next generation of road safety structures.

Structural Health Monitoring (SHM) is defined as the use of on-structure sensing system to monitor the performance of the structure and evaluate its health state. Recent bridge failures, such as the collapses of the 1-35W Highway Bridge in USA, the collapse of the Can Tho Bridge in Vietnam and the Xijiang River Bridge in the Mainland China, all of which happened in the year 2007, have alerted the importance of structural health monitoring. This book presents a background of SHM technologies together with its latest development and successful applications. It is a book launched to celebrate the establishment of the Australian Network of Structural Health Monitoring (ANSHM). The network comprising leading SHM experts in Australia promotes and advances SHM research, application, education and development in Australia. (Imprint: Nova)

This paper illustrates the damage identification and condition assessment of a three story bookshelf structure using a new frequency response functions (FRFs) based damage index and Artificial Neural Networks (ANNs). A major obstacle of using measured frequency response function data is a large size input variables to ANNs. This problem is overcome by applying a data reduction technique called principal component analysis (PCA). In the proposed procedure, ANNs with their powerful pattern recognition and classification ability were used to extract damage information such as damage locations and severities from measured FRFs. Therefore, simple neural network models are developed, trained by Back Propagation (BP), to associate the FRFs with the damage or undamaged locations and severity of the damage of the structure. Finally, the effectiveness of the proposed method is illustrated and validated by using the real data provided by the Los Alamos National Laboratory, USA. The illustrated results show that the PCA based artificial Neural Network method is suitable and effective for damage identification and condition assessment of building structures. In addition, it is clearly demonstrated that the accuracy of proposed damage detection method can also be improved by increasing number of baseline datasets and number of principal components of the baseline dataset.

This paper treats the dynamic crush response and energy absorption of aluminum foam-filled conical tubes subjected to impact loading. Nonlinear dynamic computer simulation techniques are used together with validated computer models. The main goal of the study is to generate fundamental information on the dynamic response and energy absorption of foam-filled conical tubes with respect to the variations in geometry, material and loading parameters. The research information is quantified in terms of important impact response parameters such as mean crush load, total energy absorbed and crush force efficiency that can be used in practical applications. Results indicate that foam-filled conical tubes are efficient impact energy absorbers under both axial and oblique loading conditions. The research finding can be used to develop guidance for the design of these devices for impact applications.

This thesis presents a study of techniques used to improve the performance of small vocabulary isolated word speaker dependent automatic speech recognition systems in adverse environments. Such systems are applicable to 'command and control' applications, for example industrial applications where machines are controlled by voice, providing hands-free and eyes-free operation. Adverse environments present the largest obstacle to the deployment of accurate and usable speech recognition systems. This is because they cause discrepancies between training and testing environments. Two solutions to the problem are investigated. The first is the use of secondary modelling of the output probability distribution of the primary classifiers. It is shown that a significant improvement in performance is obtained for a small vocabulary isolated word speaker dependent system, operating in an adverse environment. Results are presented of simulations using the NOISE.'-: database as well as in an actual factory environment using a real-time system. Based on the outcome of this research, a voice operated parcel sorting machine has been installed at the Australia Post Mail Centre at Underwood, Queensland. A pilot study is also undertaken for the use of lip information to enhance speech recognition accuracy in adverse environments. It is shown that the inclusion of other data sources can improve the performance of a speech recognition system.

Phenomenography is an area of research which focuses on identifying and describing the qualitatively different ways in which people understand phenomena in the world around them. Two units, structural analysis and traffic engineering, were selected for the purpose of understanding the various ways students relate to significant aspects of Civil Engineering. Integral to the study was the use of student group discussions which were recorded and analysed. The findings comprise descriptions of the different conceptions of learning held by students and lecturers in relation to specific engineering phenomena and their implications for teaching enhancement and curriculum development in Civil Engineering.

Phenomenography is an area of research which focuses on identifying and describing the qualitatively different ways in which people understand phenomena in the world around them. Two topics were selected for the purpose of understanding the various ways students relate to significant aspects of Civil Engineering. Integral to the study was the use of student group discussions which were recorded and analysed. It was possible to identify and describe the different conceptions of learning held by students in relation to specific engineering phenomena and to investigate the implications of these findings for teaching enhancement and curriculum development of Civil Engineering.

The effects of asymmetry on the response of multistorey buildings to earthquakes are presented using a simple microcomputer based procedure. The degree of asymmetry is varied by changing the position of the core in the buildings. Numerical examples are presented where results have been obtained from the quasistatic code approach and real-time dynamic analysis. Results for deflections, shear forces and bending moments are presented. Significant changes in these responses and in some cases reversal of their directions are obtained by varying the degree of asymmetry. It is also observed that not only the twisting of the building about a vertical axis but also the direction of this twisting have a significant influence on the results. The need for a three-dimensional analysis to account for the effects of assymetry is evident.

Responses of asymmetrical multistorey buildings to earthquake are obtained by the quasi-static code approach and real time dynamic analysis, using two different structural models. In the first model, all vertical members are assumed to be restrained at the slab levels and hence their end rotations, about horizontal axes, are taken as zero. In the second model this restriction is removed and the rotation is assumed to be proportional to the lateral stiffness of the member. A simple microcomputer based procedure is used in the analyses, by both models. Numerical examples are presented where results obtained from the models are given. Effects of modelling on the response of three buildings, each with a different type and degree of asymmetry, are studied. Results for deflections and shear forces are presented and the effects of the type of model on the response are discussed.

Abstract: A simple finite element method, based on the analogy with a beam on an elastic foundation, has been developed and applied to the analysis of track structures subjected to point or uniformly distributed loads, A technique for treating infinitely long tracks by using an equivalent model of finite length has also been developed and incorporated into the analysis. Variations in track and/or foundation properties along the Length of the track are easily handled in the proposed method. The entire analysis can be conveniently programmed to run on a microcomputer, and with a few elements gives fast and accurate results. Important parameters are identified and their effects on the results discussed.

A simple finite element method is presented for the axisymmetric free vibration analysis of conical shells with uniform or varying wall thickness. The method is based on an analogy with a beam on elastic foundation, where the foundation modulus and beam flexural rigidity are replaced by appropriate parameters pertaining to the shell under consideration. The technique is attractive for implementation on a microcomputer and with few elements it gives good results which compare well with other solutions.

Most high-rise buildings are asymmetric as they are unsymmetrical in plan and/or elevation or they have unsymmetrical mass distribution in the floors. Due to this there is coupling between the lateral and torsional components of the building response when subjected to lateral loads. The location of vertical members, especially heavy service cores and/or shear walls influence the amount of torsional coupling which is turn influences the building response. In this paper the effects of eccentrically locating vertical members on the response of high-rise buildings are investigated and the results discussed.

A simplified method is presented to treat the complicated problem of scattering of plane harmonic SH-waves by cavities of any shape, either in full or half space. The essence of the method is the discretization of the boundary of the cavity into a series of straight strips. By doing this only plane waves will be encountered in the analysis. An approximate method to include the effects of diffraction due to grazing waves is also incorporated. Results compare reasonably well with existing closed-form solutions. The angle of incidence of the waves is seen to be a dominant parameter in the analysis.

Column base plates have been analyzed and designed traditionally on the assumptions that the plate is rigid and that the plate thickness can be determined from the cantilever action of the plate projections beyond the column face. Recent investigations have attempted to investigate the actual behavior of column base plates and quantify the differences between the real and assumed behavior. This paper describes the salient features of the two-dimensional finite element analysis of certain base plates which had been tested in the laboratory, and presents the significant findings. The computer results confirm the observed behavior of the test specimens to a reasonable extent.

Cylindrical shells which are used as fluid or (granular) solid retaining structures and which are subjected to vibration are usually designed as having uniform thickness. However it is known that for shells under hydrostatic (and static) loads the bending and hoop stresses vary with the height of the shell. Moreover the natural frequencies of the shell can be elevated by not conforming to uniform thickness. This can enable vibration isolation of the shell and elimination from the destructive effects of resonance. In the present work, the optimum design of a cylindrical shell is treated such that the maximum stresses are near the allowable values and such that the fundamental natural frequency is made as high as possible. The static and dynamic aspects are carried out separately. In both cases the inner radius of the shell is kept constant, while the thickness (and hence the outer radius) is varied along the shell axis. Since analytical solutions are either impossible or tedious to carry out, a numerical procedure using the finite element method has been adopted. The results confirm that the design of cylindrical shells can be optimised so that material economy is achieved and the performance is enhanced.

The response of a prestressed beam subjected to an end impact is treated using the method of wavefront expansion. The impact can be prescribed in the form of stress, strain, velocity or acceleration boundary conditions. The Timoshenko equations, modified to include the initial stress, are used to model the beam. The analysis is based on the concept of a wave as a carrier of discontinuities in the field variables and their derivatives.

The effect of initial stress on the transient response of a beam subjected to impulsive end loading is investigated. This loading can be prescribed in the form of stress, strain, velocity or acceleration boundary conditions. The Timoshenko equations, modified to include the presence of initial stress, are used to model the beam. The analysis is based on the concept of a wave as a carrier of discontinuities in the field variable and its derivatives. These discontinuities are determined from a set of recurrence relations that are, in turn, generated by using time-harmonic asymptotic series solutions to the equations of motion. The numerical results obtained confirm the influence of prestress on the transient velocity, bending moment, and shear force distributions in the beam. The results for zero initial stress compare favorably with those from a closed form solution, while the other results follow a particular trend. Solutions to problems with other boundary conditions can be obtained by using the present results.

Experiments are conducted to study the behavior of base plates under the action of axial loads and moments by eccentric loading on the column. The parameters in the study are the thickness of the base plate and the eccentricity of the load. At the lowest eccentricity, failure was by cracking of the concrete, while at other eccentricities the primary mode of failure was by the yielding of the base plate. Comparisons of the test results with the predictions from the Working Stress Method gave a range of 1.09-1.89 for the factor of safety with a mean value of 1.35 for specimens that failed by yielding of the base plate. The strain distributions in the base plate were obtained at various stages of loading. They indicate the existence of a critical section of maximum strain, a section of zero strain and strain reversal. The eccentricity of the load seems to have a greater influence on the strains than the thickness of the base plate. The test results show that flexible base plates when loaded at high eccentricities fail primarily by yielding of the plate and that their behavior is somewhat different to that predicted by the present design methods.

Herein the propagation of transient waves in a rod due to impulsive end loading is investigated using the method of wavefront expansion. The Mindlin–Herrmann equations which include the Poisson effect are used to model the rod. Since this rod theory is restricted to lower values of Poisson's ratio (< 0.283), the present work also has the same restriction. The impulsive end loading on the rod can be prescribed in the form of stress, strain, velocity or acceleration boundary conditions. The analysis is based on the concept of a wave as a carrier of discontinuities in the field variables and their derivatives. These discontinuities are determined from a set of recurrence relations which are in turn generated by the use of time harmonic asymptotic series solutions to the equations of motion. Transients due to both velocity and strain (or stress) boundary conditions are treated. Numerical examples are presented to illustrate the method of solution. The results indicate the distortion of the transient waves due to the dispersive nature of the governing equations. Transients due to other boundary conditions at the rod end can be treated by using the results presented in the paper.

The propagation of higher order flexural transients in a Timoshenko beam, subjected to impulsive boundary loads is treated in this paper. The higher order transients are either generated by higher order boundary conditions or induced by homogeneous boundary conditions. The analysis is based on the concept of a wave as a carrier of discontinuities in the field variable and its derivatives. These discontinuities are determined from a set of recurrence relations which are in turn generated by the use of time-harmonic asymptotic series solutions to the equations of motion. Numerical examples are presented to illustrate the method of solution for higher order transients and the resulting velocity, bending moment and shear force distributions have been computed.