bluuebunny/crossref_metadata_2025 huggingface dataset:
Probabilistic Analysis and Optimization of Roof Trusses
Authors: A. Olsson
Published: August 2022

The influence of gap between wooden members and displaced nail-plates in roof trusses is investigated by means of probabilistic calculations and structural optimization. The employed mechanical model, using the finite element method, captures the non-linear behaviour of the nail-plate joints. The joint stiffness involves the size and location of the nail-plate, and the presence of contact or gap respectively between the wooden members. The analysis shows that even small initial gaps considerably increase the deflection of a roof truss. Misplaced nail-plates also effect the deflection negatively, but it is also shown that the deflection can be significantly decreased, and the utilization of nail-plates improved, by optimizing the nail-plate positions with respect to critical load cases and requirements.
Sensor Network Applications in Structures – A Survey
Authors: Sanath Alahakoon  , D. M. G. Preethichandra  , E. M. I. Mala Ekanayake
Published: August 2022

Sensor networks play a significant role in modern day structures. From large bridges to sky scrapers, application of sensor networks –  both wireless and wired – has strengthened the structural reliability and hence the safety of their users. The objective of this survey paper is to identify different usages of sensor networks in structures and further elaborate on different types of sensing together with the techniques associated with processing the parameters sensed by the sensor networks to achieve the desired implementation goals.
Active Ultra-Wideband Tag Design for Concrete Debris Tracking Systems
Authors: Y. Z. Shen  , C. L. Law  , K. S. Koh  , S. M. Hu
Published: August 2022

Compared with the traditional high-speed video camerameasurement method, ultra-wideband(UWB) technology is valuable in the detection and tracing of debris throw during explosion, due to its distinct advantages such as high positioning accuracy, multipath immunity, and low power consumption. In this pa-per, dielectric properties of Concrete slabs are first measured and used in the design of a slot antenna embed-ded in Concrete. An active UWB tag integrated with the slot antenna is designed for a real-time debris track-ing system. The tag size is 25 × 25 × 25 mm which can be embedded in Concrete. Due to its small size, the tag has high chance to be intact in fragmented Concrete debris in explosion. The tag has low DC power con-sumption of 22.8 mW with output pulse amplitude of 12 V peak to peak (into 50 ohms) resulting in operating range of more than 190 meters.
The use of helical spring and fluid damper isolation systems for bridge structures subjected to vertical ground acceleration
Authors: A. Parvin  , Z. Ma
Published: August 2022

In this study a combination of helical springs and fluid dampers are proposed as isolation and energy dissipation devices for bridges subjected to earthquake loads. Vertical helical springs are placed between the superstructure and substructure as bearings and isolation devices to support the bridge and to eliminate or minimize the damage due to earthquake loads. Additionally, horizontal helical springs are placed between the abutments and bridge deck to save the structure from damage. Since helical springs provide stiffness in any direction, a multi-directional seismic isolation system is achieved which includes isolation in the vertical direction. To reduce the response of displacement, nonlinear fluid dampers are introduced as energy dissipation devices. Time history analysis studies conducted show that the proposed bridge system is sufficiently flexible to reduce the response of acceleration. The response of displacement due to provided flexibility is effectively controlled by the addition of energy dissipation devices.
A Constant Displacement Iteration Algorithm for Nonlinear Static Push-Over Analyses
Authors: Graham C. Archer
Published: August 2022

This paper presents the formulation and implementation of a new static push-over analysis algorithm for the seismic rehabilitation of building frames, in accordance with “NEHRP Guidelines for the Seismic Rehabilitation of Buildings”. The concept of the push-over analysis is described and problems associated with its implementation in a nonlinear finite element program are examined. Earlier work, which contributed to the development of the strategy, is reviewed. The theory of the solution algorithm is presented with special consideration placed on the stability of the algorithm and the method of iteration for the nonlinear behavior. Examples are carried out that demonstrate the remarkably stable and efficient procedure.
Statical Analysis of Pile Groups Containing Batter Piles
Authors: J. Kent Hsiao
Published: August 2022

The traditional statical method uses two approaches for the analysis of a loaded pile group containing batter piles. The first approach uses batter piles to resist a partial lateral load; the residual lateral load is then equally distributed between each pile in the pile group; the distributed residual lateral load in each pile then results in the shear force in that pile. The second approach adjusts the slopes of the batter piles in order to resist the complete lateral load and as a result, there are no shear forces in the piles. Three examples are presented in this paper to demonstrate the use of the two approaches. The results of these three examples are then compared to the “exact” results obtained by using either computer software or a hand calculation. The study presented in this paper has concluded the following: (1) The first approach may result in significant errors; therefore, its accuracy is questionable. (2) The results obtained from the second approach are quite close to the “exact” results; therefore, the second approach is quite an accurate approximate approach for the analyses of pile groups containing batter piles.
Column Analogy in Multi-Cell Structures with Fixed Columns
Authors: A. Badir  , M. Badir
Published: August 2022

A procedure is presented for the analysis of multi-cell structures such as multi-span and mul-ti-storey frames by use of the method of column analogy, normally applicable to analysis of single-span and closed frames. The multi-cell structure is first divided into a number of cells each of which can be readily ana-lyzed by column analogy for the applied external loads. A number of simultaneous equations are then written to restore continuity of the isolated cells. Certain moment-coefficients are computed also by column analogy, and used in writing the continuity equations. Solution of these equations yields moment corrections which are superimposed to the moments of the isolated cells to arrive at the final bending moments of the multi-cell structure. The procedure is presented for the analysis of frames with fixed columns, and is applied for the analysis of three examples in order to illustrate the details of the solution. Results obtained are in excellent agreement with values calculated using the stiffness method.
Subsurface Plume Tracking Using Sparse Wireless Sensor Networks
Authors: Vidarshana Bandara  , Anura P. Jayasumana  , Ali Pezeshki  , Tissa H. Illangasekare  , Kevin Barnhart
Published: August 2022

Deployment of sensors for tracking chemical plumes such as those in the subsurface can be quite expensive. A compressed data gathering scheme for chemical plume tracking is presented. With only a fraction (about 25%) of the measurement points required to achieve a given spatial resolution this novel ap-plication of compressed sensing can track the plume within 7% accuracy compared to the case of a full sensor array. The scheme also gathers and re-distributes information of the sensors to the entire network, compress-ing with Discrete Wavelet Transform. The scheme can be used to disseminate global tracking information to sensors as well, with savings in communications by a factor of 5 in average, if such capability is required. The scheme is capable of interpolating randomly missing sensor points with significant accuracy. It also supports data fusion as a simple addition of coefficients requiring no changes to the message length.
Classification-based event detection in ecological monitoring networks
Authors: Jayant Gupchup  , Andreas Terzis  , Zhiliang Ma  , Carey Priebe
Published: August 2022

Power-budgeting is a fundamental challenge in sensor networks today and the energy requirement of different sensing modalities is unevenly distributed. As a result, it is advisable to activate power-hungry sensors only during informative periods. Using low-power sensors, one can predict these informative periods due to strong correlations exhibited by environmental modalities. In this article, we consider an application of detecting “events” using classification based methods to increase the lifetime of the network. Specifically, we explore the problem of using low-power sensors to predict precipitation, which is one of the primary drivers of ecological activity. Such predictions can allow us to schedule the activation of expensive sensors (such as CO2) when they are most informative. In order to achieve this trade-off between power and collecting informative data, we focus our efforts on predicting/ classifying precipitation based on features extracted from inexpensive ambient temperature and barometric pressure modalities. Experimental results obtained from weather data collected over multiple years demonstrates that we can achieve accuracy towards 80% using these low-cost modalities and simple linear classifiers.
The Development of an On-line Structural Health Monitoring System based on Wireless Sensor Networks
Authors: C. Oliver Yang  , Max Yen  , Ning Weng
Published: August 2022

Monitoring structural conditions of the large number of aging bridges in the national transportation infrastructure has become an important issue that directly impacts public safety. Traditional manual inspection not only requires extremely high cost but also cannot address this problem in a timely manner. The wireless sensor networks have been accepted as a promising solution to the above problems. In this paper we have presented an on-line structural health monitoring system that consists of wireless sensor networks for real- time sensing and data sever for on-line analyzing. We designed each component, integrated them to the whole system, and deployed it to one of our campus bridges. Our laboratory simulation and prototype experimental results have verified the functionality and correctness of our system.
Investigations on ballastless tracks in tunnel without reinforcement
Authors: Jia LIU  , Stephan FREUDENSTEIN
Published: August 2022

Ballastless track systems have delivered an optimal performance in the past decades. This ideal comes from the Continuously Reinforced Concrete Pavement or the Jointed Plain Concrete Pavement in road design. It can be deduced that a well-proved system for road pavement is applicable to ballastless track design after certain modifications, which could save materials and simplify the construction work as well. In this paper, a feasibility study of ballastless track forms, in which neither reinforcement nor dowel bars shall be applied have been investigated using Finite Element Analysis. The results show that this idea is feasible in long tunnel with hard and stabile substructure, if a joint spacing less than 4 m can be realized. Meanwhile, these kinds of systems cannot be applied for track with soft substructures such as mass-spring-systems, in which continuous double-layer-reinforcement and sufficient thickness of the track concrete layer are required.
Rolling contact fatigue (RCF) defects of rails in Japanese railways and its mitigation strategies
Authors: Makoto ISHIDA
Published: August 2022

Rail is the one of the most important materials to support and guide railway vehicles safely and smoothly. Since rail sufferes from various interacting forces and environmental atmosphere, wear and fatigue pose large problems with wheel and rail. Hence, wear and fatigue of wheel and rail have been studied so far to keep running safety and some level of riding comfort of vehicle taking into account track maintenance cost. In this review, rolling contact fatigue (RCF) of rail which is one of typical fatigue phenomenon for steel wheelon- rail system is focused on and the history of RCF defects and the maintenance experience of their mitigation measures in Japanese railways are described. The concept of mitigation strategy is balance between wear and RCF. Controlling wear amount is a key word to mitigate RCF defects based on selecting rail material suitable for vehicle/track interaction together with grinding and lubrication. Furthermore, the purpose of Japanese bainitic steel rail is to obtain the suitable amount of wear to prevent the initiation of RCF crack.
Intelligent Wireless Lighting Control using Wireless Sensor and Actuator Networks: A Survey
Authors: Abiodun Iwayemi  , Peizhong Yi  , Chi Zhou
Published: August 2022

Minimizing energy usage and increasing occupant comfort are the two primary objectives of intelligent and eco-friendly buildings. Energy savings of up to 70%, combined with significant occupant productivity gains are possible via the application of wireless sensor and actuator networks (WSAN). Despite the increasing interests in WSAN-based wireless intelligent lighting control, no prior survey work exists. In the paper, we aim to provide a holistic survey of various WSAN-based schemes for intelligent lighting control so that researchers interested in the field can gain up to date knowledge and inspiration for future research. Specifically, an overview of various sensor data collection and management techniques relevant to lighting control is provided; taxonomy of various intelligent decision making schemes for lighting control is detailed; moreover, open issues within this field are identified and future research directions are proposed.
Intrusion Detection System using Wireless Sensor Networks
Authors: Absar-ul-Hasan  , Ghalib A. Shah  , Ather Ali
Published: August 2022

Ground monitoring of areas of high strategic value is necessary in today’s security sensitive world. Often, military setups require tight security cordons to be established around large encampments to protect any intruder, malicious attacker or saboteur from entering the premises and compromising its security. Such monitoring requires 24 / 7 watch over the area for long durations and a high degree of stealthiest. At the same time, cost, reliability and longevity are the fundamental requirements of such a monitoring system. Hence, the ability to monitor an area for intrusion detection by using Wireless Sensor Networks (WSNs) is of great practical importance. In this paper, we describe the design and implementation of a system capable of reliable, robust and efficient monitoring for human intrusion detection. The system allows a group of cooperative but autonomous sensory devices forming a wireless network to detect human presence within the deployment area and also track the positions of moving target. We evaluate the performance of the system consisting up to 30 nodes that includes MicaZ motes and also our custom built low cost sensor nodes. Performance results show that how the custom designed sensor nodes perform equally well and coexist with MicaZ motes. Finally, through this paper, we share our experiences and the valuable lessons learned in developing such a complete running system.
Wireless Technologies for Integrated e-Operations in Offshore Environments
Authors: Malka. N. Halgamuge  , Jayantha P. Liyanage  , Mendis Priyan
Published: August 2022

In large and complex production environments it is impossible to install a full-featured physically wired network to manage operations, 24/7, because of nature and the complexity of activities and data. Wireless networking can bring major benefits in such settings, and in particular where e-Operations and smart technical solutions remains the ambition. Wireless sensor network (WSN) have the capability of real-time monitoring and automatic control of in-building environment is a vital application. Some of the challenges, for instance, the poor link quality in the transitional region may be attributed to the many obstacles within the path including concrete element, brick walls, plasterboard partitions, office furniture and other items that either absorbs or reflects these waves leading to signalloss or multi-path effects. Therefore, combination of technologies, for instance, wireless local area network (WLAN), radio frequency identification (RFID), Bluetooth, ZigBee and remote sensors would be the best solution in congested sites. Sensors can be connected to a WLAN, which then collect data and transmit it to a central location. Experts in production environments can monitor their equipment, production and process condition from a control room or an office. This paper presents a framework for potential application of such a combined solution for offshore oil & gas production environments.
Analysis of Sensory Information for Efficient Operation of Energy Management Systems in Commercial Hotels
Authors: Lanka Udawatta  , Aruna Perera  , Sanjeeva Witharana
Published: August 2022

Due to fluctuating energy prices and ever-increasing uncertainties in supply, the industrial and commercial sectors are poised to speed up introduction of energy saving mechanisms. Having badly hit by recent economic recession, the hotel industry has ever more reasons to save energy. A typical star-class hotel was chosen to conduct the energy usage optimization study presented in this paper. The hotel’s energy consumption pattern data was collected and analysed. Based on sensor information and manage information system data, cooling load requirement is correlated with the number of occupied rooms. It is shown that substantial savings can be achieved by introduction of wing operation to the hotel room allocation system. Moreover, the findings from the present study can be incorporated into a building management system (BMS) when it comes to automating the wing operations.
Damage Identification of a Concrete Arch Beam Based on Frequency Response Functions and Artificial Neural Networks
Authors: V.V. Nguyen  , U. Dackermann  , J. Li  , M. Makki Alamdari  , S. Mustapha  , P. Runcie  , L. Ye
Published: August 2022

This paper presents a vibration-based structural health monitoring (SHM) technique for the identification of damage in a concrete arch beam replica section of the Sydney Harbour Bridge. The proposed technique uses residual frequency response functions (FRFs) combined with principal component analysis (PCA) to form a damage specific feature (DSF) that is used as an input parameter to artificial neural networks (ANNs). Extensive laboratory testing and numerical modelling are undertaken to validate the method. In the proposed technique, FRFs are obtained by the standard modal testing and damage is identified using ANNs that innovatively map the DSF to the severity of damage (length of damage cut). The results of the experimental and numerical validation show that the proposed technique can successfully quantify damage induced to a concrete arch beam simulating a real life structural component of the Sydney Harbour Bridge.
Pattern Recognition Based on Time Series Analysis Using Vibration Data for Structural Health Monitoring in Civil Structures
Authors: S. Mustapha  , Y. Hu  , K. Nguyen  , M. Makki Alamdari  , U. Dackermann  , V.V. Nguyen  , J. Li  , L.Ye
Published: August 2022

A statistical pattern recognition technique was developed based on the time series analysis to detect cracking in steel reinforced concrete structures using vibration measurements. The technique has been developed for the Sydney Harbour Bridge. The measurements were collected from single and tri-axial accelerometers, which were integrated into sensor nodes that were developed at the National ICT Australia. The approach is based on two staged Auto-Regressive (AR) and Auto-Regressive with exogenous inputs (ARX) prediction models. The variation between the residual errors obtained from the intact and damaged states were used to define a Damage Index (DI) capable of identifying physical changed which could be due to structural damage. The effect of the severity of damage on the deviation of the AR-ARX model from its intact state was also scrutinised. The results of the field trial and the laboratory testing demonstrated the ability of the approach in identifying the presence of cracking and handling large volumes of data in a very efficient manner.
Use of Modal Flexibility Method to Detect Damage in Suspended Cables and the Effects of Cable Parameters
Authors: Wasanthi R. Wickramasinghe  , David P. Thambiratnam  , Tommy H.T. Chan
Published: August 2022

Modal flexibility is a widely accepted technique to detect structural damage using vibration characteristics. Its application to detect damage in long span large diameter cables such as those used in suspension bridge main cables has not received much attention. This paper uses the modal flexibility method incorporating two damage indices (DIs) based on lateral and vertical modes to localize damage in such cables. The competency of those DIs in damage detection is tested by the numerically obtained vibration characteristics of a suspended cable in both intact and damaged states. Three single damage cases and one multiple damage case are considered. The impact of random measurement noise in the modal data on the damage localization capability of these two DIs is next examined. Long span large diameter cables are characterized by the two critical cable parameters named bending stiffness and sag-extensibility. The influence of these parameters in the damage localization capability of the two DIs is evaluated by a parametric study with two single damage cases. Results confirm that the damage index based on lateral vibration modes has the ability to successfully detect and locate damage in suspended cables with 5% noise in modal data for a range of cable parameters. This simple approach therefore can be extended for timely damage detection in cables of suspension bridges and thereby enhance their service during their life spans.
An Experimental Study of Reinforced Concrete Façade Panels and Their Fixing Assemblies Subjected to Blast Loads
Authors: Tung Pham  , Ngo Tuan
Published: August 2022

This paper presents experimental studies of concrete façade response to blast pressures. The experimental program also aims to establish the influence of fixings assemblies on the performance of precast concrete façade panels. The current standardized approach of pre-cast concrete design as defined in UFC3-340-02 limits the support fixity of pre-cast wall panels to be a simply supported system. The restriction to a simply supported system in a pre-cast wall panel would lead to inefficient design due to non-optimized use of concrete panel thickness. The experimental results showed that varying fixing assemblies may lead to a partial fixity condition, which is not accounted for in the UFC3-340-02 design guideline. The partial fixity conditions observed in the experimental results indicate that there are residual capacities in the pre-cast façade systems. The efficacy of the façade panel system could be improved by taking into account partial fixity in the support system. Similarly, premature shear failure could also be prevented by understanding the additional contribution of the partial fixity on fixing assemblies.
Study on the Seismic Response Parameters of Steel Medium-Height Buildings with Framed-Tube Skeleton under Near-Fault Records
Authors: M. Azhdarifar  , A. Meshkat-Dini  , A. Sarvghad-Moghadam
Published: August 2022

In this research, the performance abilities of tube type lateral load resistant framed systems are studied in order to assess the dynamic response properties of mid-rise steel structures under effects of far and near-field ground motions. For this purpose, three 10 story structural models with separated framed tube based skeletons were selected and designed. The structural models have been designed according to the Iranian seismic code 2800 (4th edition). The main criterion which was considered to select powerful ground motions for performing nonlinear time history analyses is the existence of energized coherent velocity pulses as well as high amplitude acceleration spikes in the time history of each earthquake record. Assessment of the analytical results should emphasize the importance of both lateral displacement and drift parameters which must be taken into account during the structural design phase. Furthermore, it was concluded that the maximum drift demand is more than 0.035 and the upper level of rotation of rigid connecting zones was obtained more than 5 percentages of a radian. As a general note, it was concluded that the seismic response parameters of mid-rise steel framed tube structures are intensively influenced by those strong earthquake records which contain powerful forward directivity effects and are able to emerge long period pulses in their time histories.
Seismic Analysis of High-Rise Buildings with Transfer Slabs: State-ofthe- Art-Review
Authors: Y.M. Abdlebasset  , E.Y. Sayed-Ahmed  , S. A. Mourad
Published: August 2022

In many high-rise buildings, architectural requirements may result in a variable configuration for the vertical structural elements between the stories of the building. To accommodate such vertical elements’ discontinuity, a “transfer” floor conveying vertical and lateral loads between upper and lower stories must be introduced. A drawback of the transfer floor is the sudden change in the building's lateral stiffness at its level: the structure becomes susceptible to the formation of a soft-storey mechanism under moderate to severe earthquakes. These buildings generally showed conventional elastic behavior for frequent earthquake but suffer extensive crack in the vicinity of transfer floors for rare earthquake. In this paper, a state of the art review is presented on recent publications dealing with the seismic behavior of high rise buildings with transfer floor.
Reinforced Concrete Beams and Slabs with Bonded CFRP Laminates: Strain Compatibility Paradox
Authors: E.Y. Sayed-Ahmed  , A. A. Abdelrahman  , N. G. Shrive
Published: August 2022

Externally bonded Fibre Reinforced Polymers (FRP) Laminates have been extensively used to strengthen reinforced concrete beams and slabs in flexure. Most design codes of practice provisions assume full strain compatibility between the FRP laminates and the concrete section in order to estimate the moment re-sistance of this hybrid system. However, as shown here, strain compatibility is lost during the early stages of loading. The current design methodologies account for premature failure due to interfacial crack debonding mechanisms by limiting the strains in the FRP to low values, resulting in the use of only a small portion of the FRP laminate capacity. Experimental investigations previously performed on precast bridge girders, hollow core slabs, and beam specimens – all with CFRP laminates bonded to their soffits – highlight the loss of strain compatibility and interfacial debonding. In this paper, recommendations are presented in order to tackle both issues.
Strain Rates in Prestressed Concrete Sleepers and Effects on Cracking Loads
Authors: Javad Taherinezhad  , M. Sofi  , Mendis Priyan , Ngo Tuan
Published: August 2022

Prestressed concrete sleepers (PCSs) play an essential role in structural response and performance of ballasted railway tracks. Due to defects in track or train components, high magnitude dynamic loads may generate at the rail head and transfer to the PCSs which can generate cracks in PCSs. Cracking from dynamic loads have been reported as the most critical problem of PCSs around the world and impose an early replacement of sleepers which is a financial burden to the rail industry. This paper investigates the effects of strain rates on the strength enhancement of PCS. By using available measurements, the strain rates are calculated at two critical points of the PCSs, the rail seat and midspan. Considering the dynamic increase factor (DIF) of concrete, the cracking loads of a PCS are calculated and are compared with commonly occurring dynamic loads. Results show that the maximum strain rates at both rail seat and midspan are about 0.08 and 0.016 1/s, respectively. The increase of cracking wheel load due to the strain rate effects is about 5 to 26 percent. The results are also shown to be able to demonstrate the level cracking from dynamic loads with very short return periods.
Dynamic Behavior of Indonesian Bridges using Interferometric Radar Technology
Authors: M. Maizuar  , Lumantarna Elisa , M. Sofi  , Y. Oktavianus  , Zhang Lihai , Duffield Colin , Mendis Priyan , H. Widyastuti
Published: August 2022

Structural deterioration of critical transport infrastructures (e.g., bridges) represents trillion dollars of transportation budget. Inspection and monitoring structural deterioration of bridge structures require an innovative method for an improved quality and accuracy of measurements. This paper presents and discusses the capabilities of the recent advanced interferomertic radar technique (IBIS-S) for remote monitoring structural vibations of bridges (e.g., displacement and natural frequency). Three case studies bridges in Indonesia were selected for field measurements. The research outcomes demonstrate the potential use of interferometric radar technology as an efficient way for structural health assessment and monitoring of bridges under operational condition.
The Flexural Ductility Behavior of Reinforced Concrete Beams with Tension Lap Splices Exposed to Fire
Authors: Masood M.M. Irheem  , Omar A. El-Nawawy  , Hatem H. Gheith  , Ayman S. Abo-Beah
Published: August 2022

Based on a comprehensive review of both previous studies and implemented practices in the field of construction structures, it’s obvious that reinforcing steel bar’s length is limited. Consequently, lap-splices are commonly used in reinforced concrete (RC) structures to solve such problem. Generally, in the design process,safety and serviceability must be satisfied. In essence, in beams with lap splices it’s important to check the ductility, since some variables as fire of RC beams can change the behavior. The present paper aims to validate the effect of fire on the flexural ductility behavior of reinforced concrete beam with lap splice. An experimentaltest Program of thirteen simply supported RC beams with lap-splices were designed, cast and tested in laboratory. The main selected variables are: concrete cover, temperature and fire exposure duration. Results show that; under fire effect with different concrete cover, duration and temperature over the lap-splices zone has major effects on the ductility of RC beams. As, the ductility of beams decreases when the temperature and fire duration increases. Furthermore, ductility of RC beams increases as concrete cover increases under similar conditions. Collectively,this study shows that the fire has a major effect on the bond strength of lap-spliced RC beams and ductility has different behavior when compared with non-fired beam. Consequently, codes have to take fire effects on the lapsplice in design process.
Numerical Simulation of Stretch Bending for L-section Aluminum Alloy Profile
Authors: Y. Liu  , L. Song  , J. Yin  , F. Ma  , Z. Sha  , D. Yang  , S. Zhang
Published: August 2022

High precision stretch bending of aluminum alloy profile is the key technology for making car’s frame body. A numerical simulation study on the displacement-controlled process for a typical kind of L-section aluminum alloy profile used in high-speed rail with finite element analysis software is presented. The effect of different friction coefficients, with or without baffle and cover plate on the equivalent stress,strain and cross-sectional distortion are investigated. It is shown that the increase of the friction coefficient can increase the cross-sectional distortion, equivalent stress and strain. The installation of baffle and cover plate can significantly reduce the cross-sectional distortion in the middle section of the profile, and increase the equivalent stress and strain to some extent.
Uniaxial Dynamic Tensile Properties of Hydraulic Concrete after Freezing-Thawing Cycles
Authors: Haitao Wang  , Haoyu Sun  , Xinxin Zhuang
Published: August 2022

In this paper, freeze-thaw cycles tests of 0, 25, 50, 75 and 100 times for large aggregate concrete were carried out and uniaxial dynamic tensile tests under the strain rates of 10-5/s, 10-4/s, 10-3/s and 10-2/s were also performed. The damage morphology of the specimens after freezing-thawing cycles was observed, the mass loss after different freezing-thawing cycles, the dynamic ultimate tensile strength, peak strain and the relationship of stress-strain under different strain rates were measured. The results showed that relation curve between the mass loss of large aggregate concrete and the freezing-thawing cycles was quadratic. Under the same strain rate, the dynamic ultimate tensile strength and the peak strain decreased withthe increase of freezing-thawing cycles. With the same freezing-thawing cycles and the increase of strain rate, the dynamic ultimate tensile strength increased, while the peak strain decreased. According to the test date, the incremental portion of stress-strain curve was fitted and the failure criterion of large aggregate concrete under dynamic uniaxial tensile stress was established, which could provide the theoretical reference for the design and maintenance of large aggregate structures.
Dynamic analysis on a buried horizontal double-layer SF-type liquidstorage tank by finite element method
Authors: X. Cheng  , L. Hu  , W. Zhang  , D. Yu
Published: August 2022

To study the dynamic responses of a buried horizontal double-layer SF-type liquid-storage tank considering liquid-solid interaction, a three-dimensional finite element model of the double-layer buried horizontal liquid-storage tank is established, and the model is calculated and simulated by using FEM (finite element method). The results show that the double-layer buried horizontal SF-type liquid-storage tank is a composite multi-layer structure; thus, the dynamic responses of the inner layer, interlayer and outer layer are different under the same earthquake wave: the tank wall displacement of the interlayer is the maximum, whereas that of the outer layer is the minimum; the tank wall equivalent stress of the inner layer is the maximum, whereas that of the outer layer is the minimum; and the distributions of strain and velocity in the inner and outer layers are also different. The double-layer SF-type oil-storage tank has different dynamic response rules under the actions of the El-Centro wave and the Lanzhou wave. Compared with the El-Centro wave, the dynamic responses of the double-layer oil-storage tank are more significant under the action of the Lanzhou wave. The dynamic responses of the horizontal double SF tank are found to be closely related to the spectral characteristics of the seismic wave and exhibit different dynamic responses under different earthquakes.
Effects of Subsoil Characteristics on the Earthquake Loading of Steel Lattice Telecommunication Towers in the South Asia
Authors: A.M.L.N Gunathilaka  , C.S Lewangamage  , M.T.R Jayasinghe
Published: August 2022

Self-supporting lattice towers, which are having quite a few unique structural features, play a vital role in communication networks. Ensuring structural stability of these giant structures under all possible natural and human threats are vital as failures of such structures may cause a catastrophic human & property damages. Further, possible communication outages caused by failure of tower/towers in disaster situation are a critical as it may hamper rescue and other emergency operations. This was experienced by South and South East Asian countries during 2004 Tsunami. Hence, need of mitigating these situations have been highlighted by various reports. Therefore, ensuring structural integrity of self-supporting lattice towers under seismic forces is an essential and timely need. This paper discusses a seismic performance of four leg and three leg lattice towers under Response Spectrum analysis under different sub soil conditions. Results of seismic analyseshas also been compared with wind analyses results.
The Effect of Detailing Steel in the Compression Regions of Internal Supports on the Ductility of Reinforced Concrete Beams
Authors: B.R. Cagney  , K.W.Wong
Published: August 2022

A clause on detailing in AS 3600 stipulates that 25 percents of the maximum steel in the span of a reinforced concrete beam has to be extended beyond the near face of each internal support. This suggests that the internal support regions have more flexural ductility than the original designed amount. This ductility is obtained indirectly by determining the amount of moment that the support regions are capable of distributing. Non-linear analysis of beams designed and detailed to the design limits specified by AS3600 shows that they have substantial reserve in moment redistribution and load capacity as a result of the inclusion of steel in the compressive zones of the supports. This reserve capacity can be exploited for design and for the strengthening of beams.
Accelerograms for Dynamic Analysis under the New Australian Standard for Earthquake Actions
Authors: Lam Nelson , Wilson John , Srikanth Venkatesan
Published: August 2022

The new Australian Standard for Earthquake Actions requires buildings exceeding 50 m in height and located in areas with hazard factor of Z ≥ 0.08 (which applies to most capital cities including Canberra, Sydney, Melbourne, Adelaide and Perth) to be designed for earthquake actions based on dynamic analyses. This paper presents a methodology for generating and using artificial accelerograms for obtaining site-specific design response spectra, which could be used for dynamic analyses. This time-history analysis approach of determining earthquake actions can result in more efficient designs in comparison with using response spectra specified by the Standard. An ensemble of accelerograms simulated for both rock and soil conditions are available in an electronic file named: “accelerograms for public access.xls” which can be downloaded free from the journal website for shared usage by all. The  accelerogram file also contains listing of the baseline corrected displacement time-histories which are required for input into shaking table experiments and certain seismic simulation programs.
Non-destructive evaluation of ceramic candle filters using artificial neural networks
Authors: Kuan-Chen Fu  , Yanqin Zhou  , Lijun Li
Published: August 2022

Ceramic candle filters play an important role in coal-based turbine system for a modern power plant. However, after exposure to the high pressure and high temperature in the gas turbine chamber, the effectiveness of the filters deteriorates over time. Their failure to perform may create catastrophic consequences for the multi-million dollar equipment downstream. A non-destructive evaluation procedure using artificial neural networks is proposed to examine the filters. In lieu of experimental data, the vibration signatures of filters damaged to various degrees are created by means of analytical simulation. Then, a feed-forward artificial neural network and a radial basis function neural network are built and trained to evaluate the signatures for the purpose of determining the filters’ degree of deterioration. Good results are obtained and presented here. The application of the proposed procedure should not be confined to the ceramic candle filters alone. It is a general procedure that will find many applications on the evaluation of other structural components and engineering products in the industry.
Actions on Structures: Regulations and Standards
Authors: L. Pham
Published: August 2022

This paper presents an overview of the historical development of Australian loading specifications followed by discussions on the regulatory and policy aspects of the development. These included the historical and rational reasons for the development of each individual standard as well as the state of the current system. It is hoped that practitioners will gain some insights into the background and principles underpinning the system that is currently in place.
Calculation of Earthquake Actions on Building Structures in Australia
Authors: Lam N. T. K. , B.A. Gaull  , J.L. Wilson
Published: August 2022

This paper presents from first principles methods of evaluating the seismic performance of a building using the method of inertial forces, method of maximum energy and method of maximum displacement. The introduction of these methods forms the main thrust of the paper. Importantly, the building can be deemed safe should this be indicated by any one of the three methods none of which requires the natural period of the building nor structural response factors to be estimated. Whilst these methods are verysimple and consume little time to apply, the accuracies of the results are comparable with those from response spectrum methods. It is noted that the fundamental basis of each of these methods is very consistent with the new response spectrum model stipulated by the new Australian standard for seismic actions. A succinct and insightful account of the development of the seismic hazard model for Australia is also provided followed by a commentary on the use of dynamic analysis methods in practice.
Seismic performance of pile-to-pile cap connections: An investigation of design issues
Authors: M. Teguh  , Duffield Colin , Mendis Priyan , G.L. Hutchinson
Published: August 2022

Damage in recent earthquakes has resulted in the design of pile foundation systems becoming more conservative, particularly pile-to-pile cap connections. However, the application of current international design practice results in pile cap joint details having congested steel reinforcement in the pile cap and this is extremely difficult to construct in accordance with the designers recommendations. The formation of plastic hinges in the piles remains a serious risk. A review of critical design issues and former research investigations into the soil-structure interaction of pile systems and the findings of a three-dimensional, nonlinear finite element analysis of the system is reported. Significant gaps have been identified between current practice and the performance of piling systems when subjected to seismic events. Preliminary findings indicate potential for alternate connection details to improve performance under seismic action. The paper concludes with a concise summary of current state-of-the-art design approaches and details further research requirements.
Research on seismic safety, retrofit, and design of a steel cable-stayed bridge
Authors: H. Otsuka  , K. Yamahira  , Y. Komiya
Published: August 2022

After the 1995 Great Hanshin Earthquake, Japanese design specification of highway bridges was revised and many piers and bearing supports have been retrofitted. Large span bridges such as arch, truss, and cable-stayed bridges located in bay area of Kobe city also suffered damages from this earthquake. Therefore the investigation of seismic performance of long span bridges has been conducted for large earthquake. The Aratsu bridge constructed in 1987 is a steel cable-stayed bridge of 345m length, continuous three spans, and single plane of stay cables. The seismic performance of this bridge was examined by nonlinear time history analyses using tri-linear back bone and hysterecis loops. Furthermore fiber model analysis and FE analysis are successfully used to check the behaviors of this bridge. According to the analysis of the target bridge, weak members for large earthquake have been clarified. Install of damper and displacement restrainer, and strengthening of components of bearing supports are proposed retrofit countermeasures. The behavior of retrofitted bridge satisfies the criteria of design specification of highway bridges.
Development of the New Australian Earthquake Loading Standard
Authors: Wilson John , Lam Nelson , L. Pham
Published: August 2022

This paper outlines the development of the Australian Earthquake Loading Standard, AS1170.4 published in 2007. Australia is a country of low to moderate seismicity with a number of Magnitude 6.8 events recorded and a moderate 5.6 magnitude event in Newcastle in 1989 that killed 13 people and caused in excess of $2 Billion damage. A new design response spectrum has been developed for Australia which has a very good representation of accelerations, velocities and displacements for rock and soft soil sites. The methodology used to develop the spectrum could be extended to other countries of low to moderate seismicity. The Standard introduces a tiered approach to earthquake loading from a simplistic force based approach to a more complex displacement based method. The displacement based method has significant advantages in low seismic regions and allows designers to design for gravity and wind loads and then to carry out a displacement check for earthquake effects.
Challenges of Low-to-Moderate Seismicity in India
Authors: C.V.R.Murty  , Javed N. Malik
Published: August 2022

India is a vast country that is growing even faster. Particularly over the last decade, there has been a sudden spurt in the construction activity in the country, especially in the large low-to-moderate seismic regions of the country. But, no systems are in place to regulate these massive constructions to ensure seismic safety. This paper raises the challenges in the current practice and provides measures to overcome them. In particular, the paper argues for separate provisions for the design and construction of structures in low-tomoderate seismic regions.
A New Analytical Method for Stochastic Response of Structure-Damper System
Authors: Wei Guo  , Hong-nan Li  , Guo-huan Liu
Published: August 2022

Fundamental principles from structural dynamics, pseudo excitation method and perturbation techniques are used to develop a new fast stochastic method for seismic analysis of the combined structuredamper system. In the approach, the mathematical equation of structure-damper system is expressed in the perturbation form, based on which the inverse operation of the matrices is avoided. Moreover, the new method also does not need the solution of any complex eigenvalue problem, in contrast to other methods found in the literature. Finally, the computation efficiency of the method is examined, and numerical comparisons with exact results are carried out to verify the accuracy of the proposed method. In all cases examined, the approach presented here shows excellent agreement with the exact results.
Nonlinear Analysis of Reinforced Concrete Frames by a Combined Method
Authors: U. Starossek  , T. Löhning  , J. Schenk
Published: August 2022

A more realistic and hence nonlinear analysis of reinforced concrete structures is becoming increasingly important. A combination of the displacement method, the transfer matrix method, and a crosssection module is suggested which leads to an effective analysis method for reinforced and prestressed concrete frames. The combined method considers both material and geometrical nonlinearities including large displacements and rotations. The computation of the system is incrementally and iteratively carried out by the displacement method. At element level, an extended transfer matrix method is used. Thus neither displacement nor force shape functions are required. Instead, the axial strain and curvature distributions along the element are segmentally approximated by polynomials. The transfer matrix method provides both the element forces and the element stiffness matrix. It is recursively applied to the deformed element, which is discretised into individual segments whose number and lengths depend on the stiffness gradient. The cross section module is based on cross-sectional integration. It takes into account nonlinear material behaviour including cracking, softening and yielding of reinforcement. The combined method is presented for plane frames but can be extended to spatial systems.