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This article presents a new approach to construct parameterized reduced-order models for nonlinear circuits. The reduced model is obtained such that it matches the variations in the DC operating point of the original full circuit in response to variations in several of its key design parameters. The new approach leverages, through the use of circuit moments with respect to the design parameters, the discrete empirical interpolation approach developed in a model reduction in other domains and enables its efficient application to the problem of DC operating point in nonlinear circuits. Utilizing the idea of rooted trees, the proposed approach constructs orthogonal bases that are used in projecting the full equations of the large original nonlinear circuit onto a reduced system of nonlinear equations in a space with a much smaller dimension. The variations in the DC operating point of the full circuit are then obtained by solving the reduced system of equations, yielding significant computational savings. Numerical examples are presented to demonstrate the efficiency and accuracy of the reduced model in predicting the change in the DC operating point of the original circuit.

Expansive soils (also called reactive soils) undergo heave and settlements due to moisture changes and could result in differential movements in light weight structures. Hence, an estimation of potential ground movement is essential for designing footings for such structures. Shrink-swell index (Iss) is commonly used as a measure of soil reactivity and it is used in Australian standard of residential footing design to calculate ground movement. The shrink-swell test estimates the strain change per unit suction of an undisturbed soil sample; assuming the strain is independent of the insitu moisture content. In this study, 14 undisturbed soil samples were collected from an expansive soil site at different times over a two-year period. The sample locations were very close to each other. The samples had different insitu moisture contents varied from 22 to 37%. Test results indicate that increase in insitu moisture within that range resulted about 50% increase in Iss. Similar increment was observed in a set of samples obtained from another expansive soil site. The impact of insitu moisture content on Iss could lead to incorrect site classification. Consequently, the results of this study indicate that if the site is tested during different times of the year, it will result in different footing recommendations.

Precast concrete building cores are a widely used lateral load resisting system in low and mid-rise multi-storey buildings. However, despite their widespread use in countries like Australia or New Zealand, a very little research or experimental testing has been undertaken to assess their lateral drift behaviour. This article will present the findings and observations of a recent experimental testing programme into reinforced concrete precast building cores, which included three large-scale ‘box-shaped’ precast building core specimens. Adjacent panels in each specimen were connected together using welded stitch plate connections and then connected to foundation blocks on the top and bottom using grout tube connections. The results of the testing showed that the welded stitch plate connections were too flexible to allow full composite action to be developed in the cross-section, which meant the precast building core specimens were around 25% more flexible than an equivalent cast in-situ version. The testing also highlighted common detailing and construction deficiencies that can severely inhibit the ductility of the core.

Timber utility poles are significantly used in power and telecommunication infrastructures all over the world. The deterioration of timber with time is common due to various factors including termi...

Timber utility poles represent a significant part of the power distribution and telecommunication infrastructure. Weathering, decay induced by fungus, and termite attacks deteriorate the condition of timber poles, causing a loss in their strength and toughness. Routine inspections are carried out to assess the condition of poles using conventional inspection techniques. However, the reliability of these techniques is in question. This paper proposes the stress wave propagation (SWP) technique for condition assessment of timber poles and the direct application of the artificial neural network (ANN) pattern recognition algorithm for signal classification. A Fourier-based signal decomposition method has been adopted and the frequency domain statistical features of the decomposed subcomponents were extracted to be used as the inputs for the ANN. Experiments were conducted using both intact and defective timber poles subjected to stress wave propagation. Different ANN models have been developed to classify the signals, and several controlling parameters were evaluated to obtain the best performance model. Further, the support vector machine (SVM) and k-means clustering algorithms were employed to classify the stress wave signals from intact and defective poles. Finally, the results of developed ANN models, SVM classifiers and k-means clustering models for pole classification were compared. The obtained success rates of the ANN model, the SVM classifier and the k-means clustering algorithm were 92%, 87% and 81%, respectively. Further, the trained ANN model was used to predict the health status of in-service poles, which were uprooted and subjected to full-scale bending tests after performing the stress wave propagation.

Due to space limitations, screw anchors may be used closer to the edge of the substrate than distances recommended by manufacturers, e.g. to connect bottom plates, base plates or handrails in resid...

Screw anchors are widely used in applications such as fastening base plates in steel and metal construction, formwork and bracing, structural steel applications, railings and handrails. At present, researchers and design engineers rely on the Concrete Capacity Design (CCD) method to predict the strength of screw anchors under the tensile loading as the only method available in literature. In CCD method, the underlying assumption is that the concrete cone and combined concrete cone and pull-out failure modes are the main failure mode for anchors, whereas, previous studies have demonstrated that pull-out is also a very common failure mode of screw anchors. In this paper, experimental results of more than 180 tests on one particular type of screw anchors are studied to better understand their behaviour under tensile loading. Experimental results are classified based on the observed failure modes. New equations are proposed to predict the tensile capacity of this particular type of screw anchors associated with each of the above mentioned dominant failure modes for the first time. The experimental results are compared with the predicted values by the CCD method and specifications provided by the anchor manufacturer. It is also shown that in majority of cases, the CCD method overestimates both the experimental results and the specifications given by the manufacturer.

This letter presents a new approach for finite-element time-domain electromagnetic analysis. The new method combines the property of high-order approximation in the time domain with the crucial property of unconditional stability. The proposed method has been used in circuit simulation and relies on employing a specific formulation of the numerical inversion of the Laplace transform. The method is validated using one- and two-dimensional scattering from a dielectric object.

Behaviour of low rise cold-formed steel-framed residential structures when subject to lateral loading (e.g. wind and earthquake loads) is significantly influenced by both structural and non-structural elements. The ceiling is normally considered as a horizontal diaphragm for the distribution of such lateral loads to the bracing walls. In Australia, the ceiling diaphragm, in single and two storey cold-formed steel-framed houses, is made of plasterboard lining fixed to ceiling battens which in turn are screwed to the roof trusses. Determination of the stiffness and strength of the ceiling diaphragm is crucial for accurate distribution of the lateral load to the lateral resisting elements (e.g. bracing walls). This paper presents experimental results from tests of typical ceiling diaphragms. Further, a detailed finite element model is described which was validated against the experimental results. The model is capable of reproducing the initial stiffness, non-linear deformation and ultimate strength. The finding from this work would assist engineers in designing the lateral load resisting system for houses.

This paper presents a new approach aiming at simulating the steady-state response of dc–dc switching power converters. The proposed method uses the main concept behind the harmonic balance (HB) to compute the amplitudes of the harmonic content in the steady-state waveform. The proposed approach extends the basic HB to enable its efficient implementation to the power converter circuits, through developing equivalent frequency-domain-based stamps for ideal switching elements. The new technique is formulated to yield, along with the amplitudes of the harmonics, the switching times in the ideal switching elements, resulting in the convergence of the Newton method being obtained within few iterations. A major advantage in the proposed method is that it enables removing the control circuitry, which reduces the size of the circuit and significantly contributes to the efficiency of the method. Experimental results show significant speedup over commercial SPICE-based simulators.

The application of hysteretic damper has gained major attention in seismic resistant design of buildings. It provides an efficient and cost-effective solution to reduce the level of damage induced on the building due to seismic excitations. The efficiency of the damper is influenced by parameters such as yield strength, yield displacement and brace-damper assembly system stiffness. The premise of this paper is to investigate the effect of the uncertainty associated with the hysteretic damper design parameters on the probabilistic seismic performance of steel buildings. Two steel buildings which are designed in accordance with the European Standard design code are evaluated. The uncertainties associated with the damper design parameters are incorporated using the Optimised Latin Hypercube sampling method for different confidence levels. The building response is obtained by conducting nonlinear time history analyses in OpenSEES. The annual frequency of exceeding a damage limit state, which is quantified by integrating the seismic fragility curves and hazard curves, is computed for the steel buildings with and without consideration of the design parameter uncertainties.

The stress wave propagation technique can be effectively used to assess the condition of timber utility poles. However, reliable detection of damage based on the reflected wave within the time doma...

The project ‘Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk’ under the Bushfire and Natural Hazards Cooperative Research Centre (BNHCRC) aims to develop knowled...

This paper presents the tensile behaviour of individual Double Headed Anchored Blind Bolts (DHABBs) which are anchored within Concrete Filled Square Hollow Section (CFSHS) tubes. The DHABB consists of a conventional Headed Anchored Blind Bolt (HABB) with one additional middle head, between the existing end head in the embedded region and head next to the tube wall. A series of experiments were conducted on the pull-out of single DHABBs under monotonic and cyclic loading using different tube sizes, bolt sizes and concrete types. Detailed results from the experimental work are presented in this paper. A comprehensive three dimensional finite element model was developed and the results were compared with full scale pull-out test results. A good agreement was obtained between the FE and experimental results.

In this paper, the cyclic behavior of groups of double-headed anchored blind bolts (DHABBs), which are anchored within concrete-filled square hollow sections (CFSHSs), is investigated. The ...

One of 2019's biggest scientific challenges is the coronavirus disease (COVID-19). The current COVID-19 epidemic is still a point of interest of all researchers from every field in the hope of finding a way to have it under control. COVID-19 vaccine development is a lengthy procedure that requires several clinical studies to prove its efficacy and overcome the virus mutations. Personal Protective Equipment (PPE) as masks and gloves are essential for moving the battle out of one's body. Developing a highly efficient PPE is crucial, not only to reduce the spread of virus, but also to protect people who work at the frontline. Virus infection is one of the most serious public health problems facing the world today. Between now and then, several antiviral medicines have been tested to determine their effectiveness as prospective COVID-19 treatments. The rise of viral resistance, as well as the adverse effects associated with antiviral medications, are posing further hurdles, resulting in a decrease in their efficiency as antiviral treatments. This opens the possibility for developing an alternative antiviral material that is both safe and effective. When it comes to their potential to destroy a wide range of viruses, silver nanoparticles (Ag-NPs) laden fiber mats have emerged as a novel antiviral platform, according to the findings of the current study. In the past, Ag-NPs have been extensively examined for their antibacterial properties against a wide range of microorganisms. Their ability to combat hepatitis B and HIV has also been demonstrated to be encouraging, as has their ability to inhibit other viruses such as herpes simplex, monkey pox, and respiratory syncytial virus. Here, we tested the potential effect of silver nanoparticles as an alternative antiviral therapeutic based on their unique properties. When compared to imitative antivirals, elemental silver nanoparticles have the ability to attack many virus sites, reducing the likelihood of the virus developing resistance. Our group has been developing silver nanoparticles loaded on toilet paper seat sheets, cellulose membranes, polymer dressings, and cotton textiles in response to the persistent issue. The new generation of fiber mats will be thoroughly described and tested against SARS-CoV-2 virus. SEM, EDS, TEM, and DLS will be utilized to identify the shape of our fibers and estimate the particle size of the embedded nanoparticles.

Stress wave propagation (SWP) technique is a simple and cost-effective non-destructive testing technique which can be effectively employed for the health monitoring of timber utility poles. In this paper, Artificial Neural Network (ANN) pattern recognition algorithm is used for the classification of stress wave responses obtained from testing in-service timber poles. Thirty in-service timber poles in Victoria, Australia are tested which belong to different timber species and varying geometric parameters. The tested poles are uprooted and subjected to full scale bending tests in order to determine the failure moments. Health status of each pole is defined based on the ratio between the failure moment and the design moment capacity. 252 stress wave responses are obtained from the field testings by the application of different impacts. An ANN model is developed to classify these signals based on the defined target groups according to the health status. The mobility spectrum of the pole responses in the low frequency region and the pole diameters are selected as the inputs to the ANN model. The performance of the developed ANN model is evaluated by calculating some performance parameters. Further, Support Vector Machine (SVM) and k-nearest neighbors (k-NN) algorithms are also applied to the same data set for classification. The performance of each technique is compared to select the best performing method. Results of this study showed that the developed ANN model outperforms the other techniques for the condition assessment of timber poles using the stress wave propagation technique.

Shrink-swell behavior of expansive soils highly influences the performance of lightly loaded structures with shallow footings. Expansive soils often undergo heave and settlement due to soil moisture variation, which may cause differential movement in the structure. This phenomenon becomes critical when the changes in soil moisture are widespread due to climatic conditions. Indeed, there have been reports in the media regarding footing movements and cracks in new houses in Victoria particularly following the breaking of the last prolonged drought. As part of an ongoing research study on damage to residential structures caused by ground movements, a field site has been established on a vacant land in a western suburb of Melbourne. Soil moisture variation and corresponding ground movements are monitored using Neutron moisture probe and magnetic extensometers respectively. Soil suction variation is also measured from undisturbed samples in the laboratory. This paper describes the site selection, instrumentation and soil classification. The variations of soil properties with depth are discussed. Soil moisture variation is compared with climate data of the site and presented along with the corresponding soil layer movements.

Timber utility poles are extensively used in power distribution and telecommunication sectors to support the overhead cables and other attachments. These utility poles are designed to have sufficient inherent capacity to withstand the imposed actions. However, timber poles deteriorate with time losing the strength and toughness mainly due to weathering, decay and termite attacks. Therefore, pole failures occur when the imposed stresses on the pole exceed the remaining strength of the pole. It is essential to avoid pole failures which will have severe safety concerns and significant economic impacts. This paper presents a brief review of the currently available timber deterioration models and proposes a framework for evaluating the residual strength of the in-service timber utility poles. The developed framework permits the asset managers to evaluate the structural reliability of these assets and to determine the optimum pole replacement rates. The residual strength of an in-service pole is directly related to the remaining section modulus of the pole at its critical section which is the ground line region of the pole. Hence, this paper presents the evaluation of the remaining section modulus for sectioned pole specimens which were condemned from service due to pole replacements. Further, the variation of section modulus with the service life is illustrated for the analysed Australian pole specimens and compared with the predictions of the current deterioration models.

Modular buildings are built using factory manufactured building units or modules that are transported and assembled on-site. Among the many different types used, modules of volumetric form analogous to intermodal freight containers have the greatest potential to achieve complete building systems or fully-modular building systems where on-site work could be reduced to foundation, module assembly and the finishing of module-to-module interfaces as required. However, despite the many reported benefits, volumetric module use has some technical, logistical and regulatory issues that have constrained its widespread application. Two of such issues that have been widely reported are the lack of efficient structural systems for lateral load transfer and the lack of high-performance inter-module connections that can not only meet structural demands but can also fulfil certain constructional and manufacturing needs as well. Therefore, this paper focuses specifically on the latter of the two identified issues and briefly summarises the work conducted into its resolution.

Timber poles are widely used in electricity transmission and telecommunication sectors throughout the world. The stress wave propagation for the condition assessment of timber poles is identified as a promising non-destructive testing (NDT) technique due to its simplicity and cost-effectiveness compared to other traditional methods. In this paper, a novel damage severity evaluation criterion for timber poles is proposed on the basis of short-time wavelet entropy of the reflected stress waves. The stress waves are generated by transverse impacts close to the ground level of the pole. The reflected stress waves are recorded and processed in the time frequency domain using the discrete wavelet transform. The decomposed signal components using discrete wavelet analysis are used to determine the wavelet entropy. The wavelet entropies of intact and damaged poles are compared to obtain the relative wavelet entropy (RWE) for damage severity estimation. Further, a numerical model for an in situ pole system is developed to simulate the transverse stress wave propagation and to evaluate the capability of the proposed defect severity estimation method. The developed numerical model is validated with experimental data from controlled testing and the data from field tests. The validated numerical model is then used to simulate different defect scenarios. The wavelet entropy is sensitive to the damage severity in timber poles and can be used as an effective tool to evaluate the severity of damages.

Masonry infill walls significantly contribute to the seismic demand imposed on RC buildings. However, in general, infill walls are considered as nonstructural elements in seismic design and...

The work of breathing through north- and south-facing Portex Polar 'Blue-Line' paediatric tracheal tubes of sizes 3.0-7.0 mm ID has been measured using sinusoidal flow at equivalent ventilatory rates of 10-50 breaths min-1 with tidal volumes of 10-500 ml. North-facing tubes are designed to sit with the connection on the forehead after intubation, whilst south-facing ones are designed so that the connection sits on the chin of the patient. It was found that the total work of breathing through north-facing tubes is approximately 8% higher than the total work of breathing through south-facing tubes of the same size, irrespective of tidal volume or respiration rate. The total work of breathing was dependent on total tube length but independent of tube design. The endotracheal connectors themselves were found to contribute a significant proportion of the total work of breathing but there was no significant difference between the inspiratory and expiratory performance of the tubes.

Graphical abstract, This paper presents a method for determining values of dynamic parameters of the Hunt and Crossley model in order to estimate the amount of force generated at the point of contact (contact force) in an impact. A two-degree-of-freedom lumped-mass-system based on a non-linear visco-elastic model as proposed by Hunt and Crossley has been widely used to accurately model contact force. The primary difficulty associated with the Hunt and Crossley contact force model is the need to determine the unknown dynamic parameters of the model, which can be obtained by calibrating the model against results from high-speed impact experiments. Spherical impactors have to be placed in the gas-gun barrel for accelerating onto the target specimen. An innovative and inexpensive method proposed in this paper describes the use of compression testing on a test rig employing cylindrical specimens of colliding bodies to obtain the dynamic parameters thereby waiving away the need of costly and time-consuming impact experiments.

Reinforced concrete (RC) impact-resistance barriers, such as rockfall barriers, often consist of a cantilever RC wall, which is expected to experience flexural bending under impact loading ...

The Christchurch earthquake has given a renewed impetus to the development and use of low damage connections within moment-resisting frames in New Zealand. When using a low-damage technology, the building is designed to be easily repairable after a severe earthquake and is hence expected to be more resilient and cost-effective. This paper reports on a sub-assemblage test that investigates the behaviour of a newly proposed low damage connection between a steel beam and composite column. The connection incorporates blind-bolts, curved T-stubs and replaceable buckling restrained fuses (RBRFs). The RBRF is the only element which is allowed to yield when the earthquake level is higher than the design-based earthquake, so the establishment of a suitable strength hierarchy is vital to the success of the design. Two loading protocols have been applied using the same sub-assemblage but with a new RBRF at the start of each test; i.e. the RBRF was replaced after each test. The contributions of the connection, beam, and column to the total rotation have been summarised. The results show that a semi-rigid connection can be achieved by using this type of connection. Furthermore, an analytical approach has been proposed to predict the behaviour of this type of connection.

The Hunt and Crossley model has been demonstrated to give accurate predictions of contact force generated by the impact of a solid object. The simulated contact force values have been demonstrated to match closely with experimental results as reported in the literature. However, derivation of the expression for finding the value of the damping coefficient has never been presented. The writing of this paper was motivated by the need to fill in the important knowledge gap.

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

Impact of hailstone and flying debris in extreme weather conditions is a major contributor to damage to glazing panels and other types of building facades. Localized damage to the glazing panel in the form of Hertzian fracture is controlled mainly by the amount of force that is developed at the point of contact. Weibull statistics forms the foundation of contemporary probabilistic models designed to estimate the value of the limiting force to result in Hertzian fracture. This conventional approach to probabilistic modelling has significant shortcomings as the calibrated probabilistic parameters have to be specific to the type of installations. The alternative approach of predicting risks of Hertzian fracture is by stochastic simulations of Griffith flaws. This paper presents an adaptive stochastic simulation methodology for predicting risks of Hertzian fracture of glass which is subject to the impact by hail and flying debris. The proposed simulation model has been verified experimentally for annealed glass based on comparison of the simulated contact force values against results from experimental measurements. The introduced simulation procedure has been used for assessing the risk of Hertzian fracture in both annealed and toughened glass. The use of the adaptive stochastic modelling methodology for predicting Hertzian failure in scenarios of hail impact is illustrated in this paper by examples.

Modular building construction is an emerging trend in the construction industry. During the course of road transportation of the modular unit of a building, vehicular vibrations on the truck-trailer may cause damage to components that are attached to the unit. The amount of dynamic loading depends on many parameters including the level of loading on the vehicle, location of the centre of mass, suspension setup of the truck-trailer, and amount of damping of the vibrating parts. The effects of these parameters on the vertical motion of the trailer-chassis are the focus of interest in this study. The acceleration response spectrum representing the filtering effects of the suspension system and that of the mounting can be calculated by modelling road roughness as a stationary Gaussian process , whereas the truck-trailer-trailer is represented as a 2D pitch-plane model. Parametric variations in the acceleration response spectra are presented in the compact form of peak value curves. An algebraic expression for calculation of the maximum spectral accelerations experienced by attachments to the unit is also presented. It is concluded at the end of the study that a component mounting should be designed to withstand a vertical acceleration of the component of up to 32 m/s. 2 (or 3.3 g) in both directions in addition to gravitational acceleration . The design of mountings and their connections which satisfy this strength requirement can be deemed sufficiently robust to withstand vibration in the normal course of road transportation without the need for any further assessment. Less conservative predictions of the strength demand can be obtained using recommended algebraic expression or design charts provided in the paper.

Modular building construction relies on prefabricated modules which are assembled onsite to form complete buildings. The assembly requires modules to be connected at discrete locations and results in the formation of discontinuous diaphragms. Diaphragm discontinuities could potentially lead to structural instability or possible diaphragm failure if unaccounted for. Therefore, the primary objective of this study is to evaluate the influence of in-plane diaphragm stiffness and strength on the seismic performance of multi-story modular buildings. A simplified method is presented to establish diaphragm service stiffness considering shear deformation of individual module diaphragms as well as shear and axial deformation of diaphragm connections. This method is used to construct numerical models of a four-by-four bay four-story modular steel building. Three diaphragm stiffness levels, namely rigid, stiff and flexible, are considered for these models and were each subjected to 44 horizontal ground motions relating to seismic events having a return period of 500 years. The results show that increased diaphragm flexibility leads to inter-story drifts that are dramatically large and inertial forces that are considerably different from calculated values using the equivalent lateral force procedure described in current seismic codes. This study is extended further to evaluate performance targets for both elastic and inelastic diaphragm response under a seismic event having a return period of 2500 years. The results are used to propose new seismic design factors, which include force and ductility amplification, and could be implemented for the design of diaphragm connections in multi-story modular buildings.

Cast-in fastenings for use in concrete are widely used in Australia. While design guidelines for headed fasteners are currently in place in Europe and the US, guidance on the design of hold-down bo...

Low-damage technologies have been developed in recent years which limit the damage imposed on structural elements when a building is subjected to a very rare earthquake event. This has been achieved by a capacity design approach applied to the connections in which the ductile part of the connections yields and all other structural elements remain elastic. Examples of low-damage connections are the sliding hinge joint in steel buildings and variations associated with this, and a combination of a post-tensioning system and mild steel dissipater in precast concrete and timber buildings. A system developed by the authors uses replaceable buckling restrained fuses (RBRFs) that do not require a post-tensioning system to be used conjointly. This system has been studied both experimentally and numerically. This paper considers the use of RBRFs as an energy dissipation device installed at beam-column connections in composite moment-resistant frames. These RBRFs could be replaced after a major event, and hence would cause little disruption. A 2D building frame has been modelled for a case study and its behaviour under 100-year, 500-year and 2500-year return period earthquake events has been summarised. A consecutive earthquake with a return period of 500 years or 2500 years has been applied to the building following both 500-year and 2500-year return period earthquake events. This study was performed since there is a possibility that the consecutive earthquake would occur prior to the replacement of the RBRFs. The results show that the building could still sustain the consecutive earthquakes with little additional residual displacement.

Concrete Filled Steel Tubes (CFSTs) are being used as columns in moment resisting frames in many parts of the world. Because of their aesthetic appearance, favourable ductility and large load bearing capacity, they are popular with architects and engineers. The use of CFSTs is limited in some countries (like Australia) due to the problems and cost associated with the connection of steel beams to the closed column section, unlike open H-shaped columns where ordinary structural bolts can be used. In this paper, a structural system is proposed which uses moment resisting frames as the lateral load resisting system. This system eliminates the use of welds at the site, which is the most common method, although expensive, which is used to achieve a moment resisting connections. The proposed system uses double T-stub connections to connect universal beams on opposite sides of the CFST column, and headed anchored blind bolts are used to connect those T-stubs to the column. This system provides sufficient stiffness and strength to be used in low to mid-rise buildings in low to moderate seismic regions. The proposed system uses a capacity design method to limit the load and non-recoverable damage in the connection (especially in the anchorage). One of the components in the connection, the web of the bottom T-stub, is designed as a fuse to create a low damage system for very rare earthquakes.

Condition monitoring of mining conveyor is a highly essential task to ensure minimum disruption to the mining operational system. Failure of one or more conveyor components can result in significant operational downtime, economic loss, and safety risks. The current monitoring method still involves subjective measure from maintenance engineers, where at some cases, fault can be left undetected and leads into site incident. Therefore, there is a high demand for real-time condition monitoring technology to detect early fault on conveyor. In this study, the effective application of distributed optical fibre sensor (DOFS) was explored for long distance real-time condition monitoring of mining conveyor. The fault detection framework was developed by integrating and modifying the Isolation Forest algorithm to analyse optical signals for effective detection of defective idlers. Further, the optical signal was analysed to extract the damage progression of defective idler with time and space. The results were used to classify various levels of damage and to set appropriate damage thresholds. Also, software interface, that can be used to set the sensing parameters, to collect, analyse, and visualise the signal in real-time, was developed. Finally, the developed condition monitoring system was used to monitor a 1.6 km long section of a conveyor structure in Western Australia for a period of 10 months. The results and findings from the field monitoring were presented together with automated fault detection framework for condition monitoring of mining conveyor.

In regions of low-to-moderate seismicity, the design of multi-story buildings with strong-beams weak-columns are quite common, which triggers the formation of a soft-story collapse mechanism during rare ground motions. A design approach to overcome this issue is introducing a ductile soft-story at the first level, such that the damage is controlled, while the above stories remain in the elastic response range. In this approach, the ductile soft-story acts as an isolator and limits the damage at only the first-level, thereby reducing the cost and time of repair and improving the safety and resilience of these buildings. The use of concrete-filled steel tube (CFT) columns can be considered as an attractive solution to construct such ductile soft-stories. To validate this concept, the multi-axis substructure testing (MAST) system at Swinburne University of Technology is used to conduct a set of 3D quasi-static cyclic tests on CFT columns with both circular (CCFT) and square (SCFT) cross-section shapes. A combination of bidirectional horizontal load protocol with vertical load variation is applied to the specimens. The data obtained from these experiments are used to study the physical damage progression and hysteresis response of CCFT and SCFT columns under complex 6-DOF boundary forces. The obtained experimental data are then used to calibrate FE numerical models to conduct performance-based fragility analysis of the soft-story buildings, at the system level, and vulnerability assessment of CFT columns, at the component level. The results show confidence in the superior seismic performance of CFT columns and highlight the advantages of using these elements in the construction of seismic resilience and sustainable buildings.

This paper provides an overview and the results of a recent experimental study testing the lateral cyclic displacement capacity of limited ductile reinforced concrete (RC) walls. The experimental program included one monolithic cast in-situ rectangular wall specimen and one monolithic cast in-situ box-shaped building core specimen. The specimens were tested using the MAST system at Swinburne University of Technology. They were tested under cyclic in-plane unidirectional lateral load with a shear-span ratio of 6.5. The specimens were detailed to best match typical RC construction practices in regions of lower seismicity, e.g. Australia, which generally results in a ‘limited ductile’ classification to the Australian earthquake loading code. This reinforcement detailing consisted of constant-spaced horizontal and vertical bars on each face of the wall and lap splices of the vertical reinforcement at the base of the wall in the plastic hinge region. The rectangular wall and building core specimens both achieved a relatively good lateral displacement capacity given the limited ductile reinforcement detailing adopted. The lap splice at the base of the specimens resulted in a somewhat different post-yield curvature distribution being developed. Rather than a typical plastic hinge with distributed cracks being developed, a ‘two crack’ plastic hinge was formed. This consisted of one major crack at the base of the wall and another at the top of the lap splice, with only hairline cracks developing between these two major cracks. The majority of the plastic rotation was concentrated in each of these two major cracks.