ORCID Profile
0000-0001-8486-5236
Current Organisation
Queensland University of Technology
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Publisher: Springer Science and Business Media LLC
Date: 06-02-2018
Publisher: Informa UK Limited
Date: 02-2022
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-2015
Publisher: Springer Science and Business Media LLC
Date: 03-2019
Publisher: Elsevier BV
Date: 1990
Publisher: Springer London
Date: 2009
Publisher: Informa UK Limited
Date: 2013
Publisher: World Scientific Pub Co Pte Ltd
Date: 09-03-2018
DOI: 10.1142/S0219455418501602
Abstract: This paper presents a study on detecting structural deterioration in existing buildings using ambient vibration measurements. Deterioration is a slow and progressive process which reduces the structural performance, including load-bearing capacity. Each building has unique vibration characteristics which change in time due to deterioration and damage. However, the changes due to deterioration are generally subtler than the changes due to damage. Ex les of deterioration include subtle loss of steel-concrete bond strength, slight corrosion of reinforcement and onset of internal cracks in structural members. Whereas damage can be defined as major sudden structural changes, such as major external cracks of concrete covers. Herein, a deterioration detection method which uses structural health monitoring (SHM) data is proposed to address the deterioration assessment problem. The proposed novel vibration-based deterioration identification method is a parametric-based approach, incorporated with a nonparametric statistical test, to capture changes in the dynamic characteristics of structures. First, autoregressive (AR) time-series models are fitted to the vibration response time histories at different sensor locations. A sensitive deterioration feature is proposed for detecting deterioration by applying statistical hypotheses of two-s le [Formula: see text]-test on the model residuals, based on which a function of the resulting [Formula: see text]-values is calculated. A novel AR model order estimation procedure is proposed to enhance the sensitivity of the method. The performance of the proposed method is demonstrated through comprehensive simulations of deterioration at single and multiple locations in finite element models (FEM) of 3- and 20-storey reinforced concrete (RC) frames. The method shows a promising sensitivity to detect small levels of structural deterioration prior to damage, even in the presence of noise.
Publisher: Elsevier BV
Date: 2018
Publisher: IOP Publishing
Date: 14-06-2016
Publisher: Hindawi Limited
Date: 20-07-2012
DOI: 10.1002/STC.413
Publisher: Elsevier BV
Date: 2021
Publisher: IGI Global
Date: 2010
Publisher: Informa UK Limited
Date: 04-08-2023
Publisher: Springer Science and Business Media LLC
Date: 26-01-2013
Publisher: Elsevier BV
Date: 11-2019
Publisher: CRC Press
Date: 15-08-2013
DOI: 10.1201/B15963-97
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 04-2022
Publisher: American Society of Civil Engineers (ASCE)
Date: 02-1984
Publisher: Elsevier BV
Date: 11-2019
Publisher: SAGE Publications
Date: 09-2012
DOI: 10.1260/2041-4196.3.3.257
Abstract: Road safety barriers are used to minimise the severity of road accidents and protect lives and property. There are several types of barrier in use today. This paper reports the initial phase of research carried out to study the impact response of portable water-filled barrier (PWFB) which has the potential to absorb impact energy and hence provide crash mitigation under low to moderate speeds. Current research on the impact and energy absorption capacity of water-filled road safety barriers is limited due to the complexity of fluid-structure interaction under dynamic impact. In this paper, a novel fluid-structure interaction method is developed based on the combination of Smooth Particle Hydrodynamics (SPH) and Finite Element Method (FEM). The sloshing phenomenon of water inside a PWFB is investigated to explore the energy absorption capacity of water under dynamic impact. It was found that water plays an important role in energy absorption. The coupling analysis developed in this paper will provide a platform to further the research in optimising the behaviour of the PWFB. The effect of the amount of water on its energy absorption capacity is investigated and the results have practical applications in the design of PWFBs.
Publisher: Elsevier BV
Date: 07-1993
Publisher: Elsevier BV
Date: 04-2016
Publisher: Springer Science and Business Media LLC
Date: 2000
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 06-2021
Publisher: Informa UK Limited
Date: 08-05-2018
Publisher: Springer International Publishing
Date: 27-11-2022
Publisher: Elsevier BV
Date: 11-2017
Publisher: Wiley
Date: 05-1986
Publisher: American Society of Civil Engineers (ASCE)
Date: 04-2018
Publisher: Elsevier BV
Date: 11-2017
Publisher: Elsevier BV
Date: 08-2018
Publisher: CRC Press
Date: 31-08-2016
Publisher: Elsevier BV
Date: 12-2018
Publisher: Springer London
Date: 2011
Publisher: Elsevier BV
Date: 08-2005
Publisher: Informa UK Limited
Date: 08-2004
Publisher: IGI Global
Date: 2010
DOI: 10.4018/978-1-61692-022-7.CH013
Abstract: Assessing the structural health state of urban infrastructure is crucial in terms of infrastructure sustainability. This chapter uses dynamic computer simulation techniques to apply a procedure using vibration-based methods for damage assessment in multiple-girder composite bridges. In addition to changes in natural frequencies, this multi-criteria procedure incorporates two methods, namely, the modal flexibility and the modal strain energy method. Using the numerically simulated modal data obtained through finite element analysis software, algorithms based on modal flexibility and modal strain energy change, before and after damage, are obtained and used as the indices for the assessment of structural health state. The feasibility and capability of the approach is demonstrated through numerical studies of a proposed structure with six damage scenarios. It is concluded that the modal strain energy method is capable of application to multiple-girder composite bridges, as evidenced through the ex le treated in this chapter.
Publisher: IGI Global
Date: 2010
DOI: 10.4018/978-1-61692-022-7.CH015
Abstract: P Infrastructure engineering and sustainable design are among the important drivers of sustainable development. Increased industrialisation has brought to the forefront the susceptibility of concrete columns (in both buildings and bridges) to vehicle impacts. Accurate vulnerability assessments are crucial in the design process due to the possibly catastrophic nature of the failures that can occur. This chapter reports on research undertaken to investigate the impact capacity of columns of low to medium raised buildings designed according to the Australian standards. Numerical simulation techniques were used in the process and validation was done by using experimental results published in the literature. The investigation thus far has confirmed the vulnerability of typical columns in five story buildings located in urban areas to medium velocity car impacts. Hence, these columns need to be re-designed or retrofitted. In addition, accuracy of the simplified method presented in EN 1991-1-7 to quantify the impact damage was scrutinised. A simplified concept to assess the damage caused by all collision modes was introduced. The research information will be extended to generate a common database to assess the vulnerability of columns in urban areas to the new generation of vehicles. /P P & nbsp /P
Publisher: CRC Press
Date: 30-03-2016
DOI: 10.1201/B21185-167
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 2024
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 11-1996
Publisher: Elsevier BV
Date: 2008
Publisher: Elsevier BV
Date: 2020
Publisher: IGI Global
Date: 2010
DOI: 10.4018/978-1-61692-022-7.CH017
Abstract: Managing the sustainability of urban infrastructure requires regular health monitoring of key infrastructure such as bridges. The process of structural health monitoring involves monitoring a structure over a period of time using appropriate sensors, extracting damage sensitive features from the measurements made by the sensors, and analysing these features to determine the current state of the structure. Various techniques are available for structural health monitoring of structures, and acoustic emission is one technique that is finding an increasing use in the monitoring of civil infrastructures such as bridges. Acoustic emission technique is based on the recording of stress waves generated by rapid release of energy inside a material, followed by analysis of recorded signals to locate and identify the source of emission and assess its severity. This chapter first provides a brief background of the acoustic emission technique and the process of source localization. Results from laboratory experiments conducted to explore several aspects of the source localization process are also presented. The findings from the study can be expected to enhance knowledge of the acoustic emission process, and to aid the development of effective bridge structure diagnostics systems.
Publisher: Informa UK Limited
Date: 2013
Publisher: Elsevier BV
Date: 08-2021
Publisher: Mathematical Sciences Publishers
Date: 10-2006
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-1987
Publisher: Informa UK Limited
Date: 04-1988
Publisher: Elsevier BV
Date: 07-1990
Publisher: Elsevier BV
Date: 07-2022
Publisher: SAGE Publications
Date: 10-02-2014
Abstract: The use of Mahalanobis squared distance–based novelty detection in statistical damage identification has become increasingly popular in recent years. The merit of the Mahalanobis squared distance–based method is that it is simple and requires low computational effort to enable the use of a higher dimensional damage-sensitive feature, which is generally more sensitive to structural changes. Mahalanobis squared distance–based damage identification is also believed to be one of the most suitable methods for modern sensing systems such as wireless sensors. Although possessing such advantages, this method is rather strict with the input requirement as it assumes the training data to be multivariate normal, which is not always available particularly at an early monitoring stage. As a consequence, it may result in an ill-conditioned training model with erroneous novelty detection and damage identification outcomes. To date, there appears to be no study on how to systematically cope with such practical issues especially in the context of a statistical damage identification problem. To address this need, this article proposes a controlled data generation scheme, which is based upon the Monte Carlo simulation methodology with the addition of several controlling and evaluation tools to assess the condition of output data. By evaluating the convergence of the data condition indices, the proposed scheme is able to determine the optimal setups for the data generation process and subsequently avoid unnecessarily excessive data. The efficacy of this scheme is demonstrated via applications to a benchmark structure data in the field.
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 10-2014
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2021
Publisher: Elsevier BV
Date: 2014
Publisher: American Institute of Aeronautics and Astronautics
Date: 15-04-1985
DOI: 10.2514/6.1985-715
Publisher: CRC Press
Date: 03-11-2016
DOI: 10.1201/B21889-133
Publisher: Civil-Comp Press
Date: 2012
DOI: 10.4203/CCP.96.53
Publisher: Informa UK Limited
Date: 03-04-2017
Publisher: SAGE Publications
Date: 05-2012
DOI: 10.1260/1369-4332.15.5.727
Abstract: This paper presents two novel concepts to enhance the accuracy of damage detection using the Modal Strain Energy based Damage Index (MSEDI) with the presence of noise in the mode shape data. Firstly, the paper presents a sequential curve fitting technique that reduces the effect of noise on the calculation process of the MSEDI, more effectively than the two commonly used curve fitting techniques namely, polynomial and Fourier's series. Secondly, a probability based Generalized Damage Localization Index (GDLI) is proposed as a viable improvement to the damage detection process. The study uses a validated ABAQUS finite-element model of a reinforced concrete beam to obtain mode shape data in the undamaged and damaged states. Noise is simulated by adding three levels of random noise (1%, 3%, and 5%) to the mode shape data. Results show that damage detection is enhanced with increased number of modes and s les used with the GDLI.
Publisher: Informa UK Limited
Date: 05-2012
Publisher: Elsevier BV
Date: 09-1995
Publisher: Mathematical Sciences Publishers
Date: 12-2006
Publisher: Elsevier BV
Date: 06-2009
Publisher: Elsevier BV
Date: 2013
Publisher: Bentham Science Publishers Ltd.
Date: 17-12-2009
Publisher: Elsevier BV
Date: 09-2001
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 2002
Publisher: American Society of Civil Engineers (ASCE)
Date: 09-2015
Publisher: Elsevier BV
Date: 10-2014
Publisher: Elsevier BV
Date: 04-2021
Publisher: World Scientific Pub Co Pte Lt
Date: 06-2020
DOI: 10.1142/S0219455420400027
Abstract: This study attempts to propose innovative multi-layer cement-based composites to have high impact resistance which could be used for runway. In this paper, the performances of two innovative multi-layer composite runway pavements using asphalt concrete-high strength concrete-cement-treated aggregate and asphalt concrete-high strength concrete-cement mortar in surface-base-subbase layer were evaluated under impact loads. ABAQUS/Explicit software was used to simulate loading condition and nonlinear stabilized runway pavement layers characteristics. In addition, a detailed parametric study was also carried out to explore the effects of the selected materials and load-related parameters in changing the performance of multi-layer composites. The findings of the study will be helpful to introduce protective multi-layer composite runway pavement and consequently to reduce the maintenance work of runway pavement.
Publisher: Elsevier BV
Date: 09-2022
Publisher: Civil-Comp Press
Date: 2012
DOI: 10.4203/CCP.99.293
Publisher: Inderscience Publishers
Date: 2016
Publisher: American Society of Civil Engineers (ASCE)
Date: 09-2002
Publisher: Informa UK Limited
Date: 02-03-2020
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-2021
Publisher: Elsevier BV
Date: 11-2010
Publisher: IGI Global
Date: 2016
DOI: 10.4018/978-1-4666-9619-8.CH071
Abstract: Structural Dynamics has gained prominence recently due to (i) vibration problems in slender structures that have emerged as a result of new materials technology and aesthetic requirements, (ii) ageing bridge structures whose health needs to be monitored and appropriate retrofitting carried out to prevent failure and (iii) increased vulnerability of structures to seismic, impact and blast loads. Knowledge of structural dynamics is necessary to address these issues and their consequences. In recent times, structural dynamics research has generated considerable amount of new knowledge to address these issue, but this is not readily available to practicing engineers as very little or none of it enters the class rooms. This paper argues for the need to include structural dynamics and the new research knowledge into the syllabus of all civil engineering courses, especially those with a major in structural engineering. This will enable our future structural engineers to design and maintain safe and efficient structures.
Publisher: Sri Lanka Journals Online (JOL)
Date: 30-06-2010
Publisher: IEEE
Date: 07-2009
Publisher: Elsevier BV
Date: 07-2017
Publisher: Elsevier BV
Date: 02-1988
Publisher: Elsevier BV
Date: 11-1985
Publisher: Elsevier BV
Date: 05-2010
Publisher: Civil-Comp Press
Date: 2013
DOI: 10.4203/CCP.102.131
Publisher: Elsevier BV
Date: 08-2016
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 02-2018
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 10-2002
Publisher: Elsevier BV
Date: 11-2016
Publisher: Civil-Comp Press
Date: 2006
DOI: 10.4203/CCP.83.255
Publisher: Elsevier BV
Date: 04-2014
Publisher: SAGE Publications
Date: 19-02-2014
Abstract: Structural damage detection using measured dynamic data for pattern recognition is a promising approach. These pattern recognition techniques utilize artificial neural networks and genetic algorithm to match pattern features. In this study, an artificial neural network–based damage detection method using frequency response functions is presented, which can effectively detect nonlinear damages for a given level of excitation. The main objective of this article is to present a feasible method for structural vibration–based health monitoring, which reduces the dimension of the initial frequency response function data and transforms it into new damage indices and employs artificial neural network method for detecting different levels of nonlinearity using recognized damage patterns from the proposed algorithm. Experimental data of the three-story bookshelf structure at Los Alamos National Laboratory are used to validate the proposed method. Results showed that the levels of nonlinear damages can be identified precisely by the developed artificial neural networks. Moreover, it is identified that artificial neural networks trained with summation frequency response functions give higher precise damage detection results compared to the accuracy of artificial neural networks trained with in idual frequency response functions. The proposed method is therefore a promising tool for structural assessment in a real structure because it shows reliable results with experimental data for nonlinear damage detection which renders the frequency response function–based method convenient for structural health monitoring.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 10-2021
Publisher: Informa UK Limited
Date: 17-06-2019
Publisher: SAGE Publications
Date: 07-2014
Abstract: This article presents the field applications and validations for the controlled Monte Carlo data generation scheme. This scheme was previously derived to assist the Mahalanobis squared distance–based damage identification method to cope with data-shortage problems which often cause inadequate data multinormality and unreliable identification outcome. To do so, real-vibration datasets from two actual civil engineering structures with such data (and identification) problems are selected as the test objects which are then shown to be in need of enhancement to consolidate their conditions. By utilizing the robust probability measures of the data condition indices in controlled Monte Carlo data generation and statistical sensitivity analysis of the Mahalanobis squared distance computational system, well-conditioned synthetic data generated by an optimal controlled Monte Carlo data generation configurations can be unbiasedly evaluated against those generated by other set-ups and against the original data. The analysis results reconfirm that controlled Monte Carlo data generation is able to overcome the shortage of observations, improve the data multinormality and enhance the reliability of the Mahalanobis squared distance–based damage identification method particularly with respect to false-positive errors. The results also highlight the dynamic structure of controlled Monte Carlo data generation that makes this scheme well adaptive to any type of input data with any (original) distributional condition.
Publisher: Trans Tech Publications, Ltd.
Date: 07-2016
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.846.151
Abstract: Building structures use brittle materials extensively. Under impact or blast loads these structures perform poorly due to tensile strains caused by Poisson’s effect normal to the direction of such loadings. Auxetic materials exhibit negative Poisson’s ratio – a property which can be exploited to eliminate those tensile strains. In this study, Auxetic layers embedded masonry is modelled using a representative volume element (RVE) with periodic boundary conditions and an explicit finite element (EFE) modelling method for a boundary value problem of a masonry wall with an Auxetic foam rendered face is subject to out-of-plane load. The RVE is limited to in-plane loads only and hence subjected to in-plane shear and compression and the EFE was used to assess the performance under out-of-plane loading. The results show significant post-yield strain hardening under axial compression and in-plane shear and high increase in capacity for walls under out of plane flexure.
Publisher: Hindawi Limited
Date: 20-11-2013
DOI: 10.1002/STC.1535
Publisher: Elsevier BV
Date: 12-1995
Publisher: Springer Science and Business Media LLC
Date: 20-11-2018
Publisher: Elsevier BV
Date: 08-2022
Publisher: Elsevier BV
Date: 1990
Publisher: School of Civil Engineering, The University of Queensland
Date: 2015
Publisher: SAGE Publications
Date: 05-2012
DOI: 10.1260/1369-4332.15.5.707
Abstract: Acoustic emission (AE) is the phenomenon where stress waves are generated due to rapid release of energy within a material caused by sources such as crack initiation or growth. AE technique involves recording the stress waves by means of sensors and subsequent analysis of the recorded signals to gather information about the nature of the source. Though AE technique is one of the popular non destructive evaluation (NDE) techniques for structural health monitoring of mechanical, aerospace and civil structures several challenges still exist in successful application of this technique. Presence of spurious noise signals can mask genuine damage-related AE signals hence a major challenge identified is finding ways to discriminate signals from different sources. Analysis of parameters of recorded AE signals, comparison of litudes of AE wave modes and investigation of uniqueness of recorded AE signals have been mentioned as possible criteria for source differentiation. This paper reviews common approaches currently in use for source discrimination, particularly focusing on structural health monitoring of civil engineering structural components such as beams and further investigates the applications of some of these methods by analyzing AE data from laboratory tests.
Publisher: Elsevier BV
Date: 11-2004
Publisher: American Concrete Institute
Date: 2019
DOI: 10.14359/51710862
Publisher: CRC Press
Date: 08-03-2018
Publisher: SAGE Publications
Date: 03-2014
DOI: 10.1260/1369-4332.17.3.319
Abstract: The use of Wireless Sensor Networks (WSNs) for vibration-based Structural Health Monitoring (SHM) has become a promising approach due to many advantages such as low cost, fast and flexible deployment. However, inherent technical issues such as data asynchronicity and data loss have prevented these distinct systems from being extensively used. Recently, several SHM-oriented WSNs have been proposed and believed to be able to overcome a large number of technical uncertainties. Nevertheless, there is limited research verifying the applicability of those WSNs with respect to demanding SHM applications like modal analysis and damage identification. Based on a brief review, this paper first reveals that Data Synchronization Error (DSE) is the most inherent factor amongst uncertainties of SHM-oriented WSNs. Effects of this factor are then investigated on outcomes and performance of the most robust Output-only Modal Analysis (OMA) techniques when merging data from multiple sensor setups. The two OMA families selected for this investigation are Frequency Domain Decomposition (FDD) and data-driven Stochastic Subspace Identification (SSI-data) due to the fact that they both have been widely applied in the past decade. Accelerations collected by a wired sensory system on a large-scale laboratory bridge model are initially used as benchmark data after being added with a certain level of noise to account for the higher presence of this factor in SHM-oriented WSNs. From this source, a large number of simulations have been made to generate multiple DSE-corrupted datasets to facilitate statistical analyses. The results of this study show the robustness of FDD and the precautions needed for SSI-data family when dealing with DSE at a relaxed level. Finally, the combination of preferred OMA techniques and the use of the channel projection for the time-domain OMA technique to cope with DSE are recommended.
Publisher: World Scientific Pub Co Pte Lt
Date: 09-11-2018
DOI: 10.1142/S0219455418501626
Abstract: Evaluating the performance of beam-like structures in terms of their current boundary conditions, stiffness and modal properties can be challenging as the structures behave differently from their designed conditions due to aging. The purpose of the current study is to determine the flexural rigidity of beam-like structures when their support conditions are not fully understood. A novel optimization scheme is proposed for estimation of the flexural stiffness and the capacity of the beam-like structures under moving loads. The proposed method is applied to various profiles of the beams made of different materials with unknown boundary conditions, and the effects of damage, excitation and optimization algorithm are rigorously investigated. The results of the numerical and experimental studies showed that the proposed substructural bending rigidity identification (SBI) method can correctly assess the in-service flexural stiffness, fixity of the boundary condition and the load-carrying capacity. This technique can be considered as a cost-effective method for periodic monitoring, load rating and model updating of the beam-like structures.
Publisher: Civil-Comp Press
Date: 2013
DOI: 10.4203/CCP.102.142
Publisher: Elsevier BV
Date: 1983
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 03-2020
Publisher: Wiley
Date: 09-1986
Publisher: SAGE Publications
Date: 05-2012
DOI: 10.1260/1369-4332.15.5.717
Abstract: Columns and walls in buildings are subjected to a number of load increments during the construction and service stages. The combination of these load increments and poor quality construction can cause defects in these structural components. In addition, defects can also occur due to accidental or deliberate actions by users of the building during construction and service stages. Such defects should be detected early so that remedial measures can be taken to improve life time serviceability and performance of the building. This paper uses micro and macro model upgrading methods during construction and service stages of a building based on the mass and stiffness changes to develop a comprehensive procedure for locating and detecting defects in columns and walls of buildings. Capabilities of the procedure are illustrated through ex les.
Publisher: Elsevier BV
Date: 04-2021
Publisher: Nova Science Publishers
Date: 2022
DOI: 10.52305/QHVI3457
Publisher: World Scientific Pub Co Pte Lt
Date: 09-2020
DOI: 10.1142/S0219455420420080
Abstract: This paper presents an enhanced method to locate and quantify damage in beam-like structures using changes in deflections estimated from modal flexibility (MF) matrices. The method is developed from explicit relationship between a series of MF-based deflection change vectors and the damage characteristics. Based on this, three damage locating criteria are defined and used to detect and locate damage. Once the damage is located, its severity is estimated conveniently from a closed-form function. The capability of the proposed method is examined through numerical and experimental verifications on a steel beam model. The result shows that the method accurately locates and quantifies damage under various scenarios using a few modes of vibration, with satisfactory or even better results compared to those obtained from traditional static deflection-based method. The performance of the proposed method is also compared with three well-known vibration-based damage detection methods using changes in MF and modal strain energy. It is found that the proposed method outperformed the other three methods, especially for multiple damage cases. As beams can represent various structural components, the proposed method provides a promising damage identification tool targeting the application to real-life structures.
Publisher: Wiley
Date: 1980
Publisher: Elsevier BV
Date: 05-2014
Publisher: Elsevier BV
Date: 2017
Publisher: Thomas Telford Ltd.
Date: 12-2005
DOI: 10.1680/BREN.2005.158.4.201
Abstract: A cable-supported footbridge model with pre-tensioned cables in vertical and horizontal planes is proposed to investigate the vibration characteristics of shallow suspension footbridges under walking dynamic loads in this conceptual study. In this bridge model, the tension forces in the supporting cables can be adjusted by introducing pre-tensions to the reverse-profiled cables, and therefore the natural frequencies can be altered to cover the frequency range of dynamic forces induced by pedestrians. In the numerical analysis, SAP2000 is adopted to study the vibration properties and dynamic response under walking loads. The synchronous response of the bridge structure is stimulated by resonant vibration. The crowd walking loads are modelled as uniform loads acting on the whole bridge deck and they consist of three parts: vertical dynamic force, lateral dynamic force and vertical static force. Numerical results show that for a shallow suspension footbridge the lowest frequencies correspond to lateral and torsional vibration modes which are always combined together and become two types of coupled modes: coupled lateral–torsional modes, as well as coupled torsional–lateral modes. As an ex le, a bridge model with fundamental frequency of 0·75 Hz in the lateral direction has been studied. It is found that the vibration in the lateral direction is quite different from that in the vertical direction and that d ing has significant effect on the vertical vibration but small effect on the lateral one. Moreover, vertical static load has significant effect on the lateral vibration when the bridge structure vibrated in coupled modes.
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.763
Abstract: Portable water-filled road barriers (PWFB) are roadside structures placed on temporary construction zones to separate work site from traffic. Recent changes in governing standards require PWFB to adhere to strict compliance in terms of lateral displacement and vehicle redirectionality. Actual PWFB test can be very costly, thus researchers resort to Finite Element Analysis (FEA) in the initial designs phase. There has been many research conducted on concrete barriers and flexible steel barriers using FEA, however not many was done pertaining to PWFB. This research probes a new technique to model joints in PWFB. Two methods to model the joining mechanism are presented and discussed in relation to its practicality and accuracy. 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.
Publisher: Elsevier BV
Date: 1988
Publisher: IGI Global
Date: 04-2014
DOI: 10.4018/IJQAETE.2014040103
Abstract: Structural Dynamics has gained prominence recently due to (i) vibration problems in slender structures that have emerged as a result of new materials technology and aesthetic requirements, (ii) ageing bridge structures whose health needs to be monitored and appropriate retrofitting carried out to prevent failure and (iii) increased vulnerability of structures to seismic, impact and blast loads. Knowledge of structural dynamics is necessary to address these issues and their consequences. In recent times, structural dynamics research has generated considerable amount of new knowledge to address these issue, but this is not readily available to practicing engineers as very little or none of it enters the class rooms. This paper argues for the need to include structural dynamics and the new research knowledge into the syllabus of all civil engineering courses, especially those with a major in structural engineering. This will enable our future structural engineers to design and maintain safe and efficient structures.
Publisher: SAGE Publications
Date: 03-11-2019
Abstract: For assessment of existing bridges, load rating is usually performed to assess the capacity against vehicular loading. Codified load rating can be conservative if the rating is not coupled with the field data or if simplifications are incorporated into assessment. Recent changes made to the Australian Bridge assessment code (AS 5100.7) distinguish the difference between design and assessment requirements, and include addition of structural health monitoring for bridge assessment. However, very limited guidelines are provided regarding higher order assessment levels, where more refined approaches are required to optimize the accuracy of the assessment procedure. This article proposes a multi-tier assessment procedure for capacity estimation of existing bridges using a combination of structural health monitoring techniques, advanced nonlinear analysis, and probabilistic approaches to effectively address the safety issues on aging bridges. Assessment of a Box Girder bridge was carried out according to the proposed multi-tier assessment, using data obtained from modal and destructive testing. Results of analysis at different assessment tiers showed that both load-carrying capacity and safety index of the bridge vary significantly if current bridge information is used instead of as-designed bridge information. Findings emerged from this study demonstrated that accuracy of bridge assessment is significantly improved when structural health monitoring techniques along with reliability approaches and nonlinear finite element analysis are incorporated, which will have important implications that are relevant to both practitioners and asset managers.
Publisher: Springer International Publishing
Date: 29-08-2015
Publisher: Elsevier BV
Date: 1987
Publisher: Elsevier BV
Date: 1990
Publisher: Elsevier BV
Date: 03-1991
Publisher: Elsevier BV
Date: 03-2014
Publisher: Elsevier BV
Date: 11-2020
Publisher: Springer International Publishing
Date: 29-08-2015
Publisher: Australasian College of Road Safety
Date: 24-05-2019
DOI: 10.33492/JACRS-D-18-00296
Abstract: The tractrix curve, sometimes called the pursuit curve has long been the standard used to describe the path of a pig trailer behind a prime mover. This ideal path still has validity today provided the speed is very low and the trailer is unloaded. During a common phenomenon of snaking or fishtailing, the trailer sways back and forth in relation to the prime mover centreline axis. Often regarded as the nightmare of caravanning, the action does not follow the tractrix curve but follows a shorter path to the common centreline of prime mover and trailer. This paper explores the shorter path in response to a tyre reaction to centripetal force causing slip steer. An ex le derived by drafting progression steps to how quantitatively that speed causes early cross-over carrying more energy into the next fishtailing phase is presented. It is believed the inclusion of slip steering to modify a tractrix curve is a novel development.
Publisher: Elsevier BV
Date: 1979
Publisher: SAGE Publications
Date: 2013
DOI: 10.1260/1369-4332.16.1.165
Abstract: Vertical displacements are one of the most relevant parameters for structural health monitoring of bridges in both the short and long terms. Bridge managers around the globe are always looking for a simple way to measure vertical displacements of bridges. However, it is difficult to carry out such measurements. On the other hand, in recent years, with the advancement of fiber-optic technologies, fiber Bragg grating (FBG) sensors are more commonly used in structural health monitoring due to their outstanding advantages including multiplexing capability, immunity of electromagnetic interference as well as high resolution and accuracy. For these reasons, using FBG sensors is proposed to develop a simple, inexpensive and practical method to measure vertical displacements of bridges. A curvature approach for vertical displacement measurements using curvature measurements is proposed. In addition, with the successful development of FBG tilt sensors, an inclination approach is also proposed using inclination measurements. A series of simulation tests of a full-scale bridge was conducted. It shows that both of the approaches can be implemented to determine vertical displacements for bridges with various support conditions, varying stiffness ( EI) along the spans and without any prior known loading. These approaches can thus measure vertical displacements for most of slab-on-girder and box-girder bridges. Besides, the approaches are feasible to implement for bridges under various loading. Moreover, with the advantages of FBG sensors, they can be implemented to monitor bridge behavior remotely and in real time. A beam loading test was conducted to determine vertical displacements using FBG strain sensors and tilt sensors. The discrepancies as compared with dial gauges reading using the curvature and inclination approaches are 0.14mm (1.1%) and 0.41mm (3.2%), respectively. Further recommendations of these approaches for developments will also be discussed at the end of the paper.
Publisher: Elsevier BV
Date: 02-2009
Publisher: Informa UK Limited
Date: 16-11-2017
Publisher: Elsevier BV
Date: 09-2001
Publisher: Springer Science and Business Media LLC
Date: 16-12-2016
Publisher: American Society of Civil Engineers (ASCE)
Date: 09-2017
Publisher: World Scientific Pub Co Pte Lt
Date: 09-2020
DOI: 10.1142/S0219455420420109
Abstract: Vibration-based methods can be used to detect damage in a structure as its vibration characteristics change with physical changes in the structure. Arch bridge is a popular type of bridge with rather complex vibration characteristics which pose a challenge for using existing vibration-based methods to detect damage in the bridge. Further, its particular geometry with a curved arch rib and vertical members (either in compression or tension) to support the horizontal deck makes the process of damage quantification using vibration-based methods harder and challenging. This paper develops and presents a vibration-based method that utilizes damage pattern changes in frequency response functions (FRFs) and artificial neural networks (ANNs) to locate and quantify damage in the rib of deck-type arch bridge, which is the most important load bearing component in the bridge. Principal component analysis, which is performed to reduce the dimension of original FRF data series and to obtain limited principal component analysis (PCA)-compressed FRF data is used in the development of the proposed method. FRF change, which is the difference in the FRF data between the intact and the damaged structure, is compressed to a few principal components and fed to ANNs to predict the location and severity of structural damage. The process and the hierarchy of developed ANN systems are presented, including the “fusion network” concept, which in idually analyses FRF-based damage indicators separated by sensor locations. Finally, results obtained for many tested damage cases (inverse problems) are presented, which demonstrate the applicability of the proposed method for locating and quantifying damage in the rib of deck type arch bridge.
Publisher: Wiley
Date: 08-2023
DOI: 10.1002/EQE.3981
Abstract: Two roof structures representing vintage unreinforced masonry (URM) building components were subjected to longitudinal pseudo‐static cyclic loading. The overall roof dimensions were 8.94 m (span) by 3.1 m (length), with each roof incorporating a pair of as‐built timber trusses that were retrieved from two demolished URM buildings. Both roofs were tested first with nailed connections representing original construction and then again with connections that included proprietary metal brackets and straps representing a remediation of the original construction. The loading was applied perpendicular to the trusses, hence parallel to the diaphragm purlins. Damage patterns and deformation profiles were used to interpret the mechanics governing the roof behaviour utilizing existing modelling techniques for timber floors. It was found that the roof behaviour was shear‐dominated, akin to the in‐plane response of timber floors. For the direction of applied loading, both roof stiffness and roof strength were governed by the strength of the connections between the trusses and the diaphragm purlin members and the purlin spacing. Consistent with these findings, a method was suggested to estimate the stiffness and strength of similar roof structures that may have different aspect ratios using the results from the tests. A comparison between the various test results showed that implementing upgrades that were focused on the connections significantly improved the roof stiffness and roof strength.
Publisher: Elsevier BV
Date: 06-2022
Publisher: Informa UK Limited
Date: 1985
Publisher: School of Civil Engineering, The University of Queensland
Date: 2015
Publisher: Inderscience Publishers
Date: 2018
Publisher: Elsevier BV
Date: 02-2004
Publisher: Elsevier BV
Date: 02-1993
Publisher: Informa UK Limited
Date: 2012
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 03-2003
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Singapore
Date: 04-09-2020
Publisher: Elsevier BV
Date: 09-2009
Publisher: Informa UK Limited
Date: 2013
Publisher: Wiley
Date: 11-1993
Publisher: Elsevier BV
Date: 02-2001
Publisher: Springer Science and Business Media LLC
Date: 28-03-2016
Publisher: Springer Science and Business Media LLC
Date: 03-06-2016
Publisher: Informa UK Limited
Date: 31-07-2009
Publisher: SAGE Publications
Date: 03-03-2022
DOI: 10.1177/20414196211073502
Abstract: 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.
Publisher: Elsevier BV
Date: 10-2014
DOI: 10.1016/J.AAP.2014.05.010
Abstract: Portable water-filled barriers (PWFBs) are roadside appurtenances that prevent vehicles from penetrating into temporary construction zones on roadways. PWFBs are required to satisfy the strict regulations for vehicle re-direction in tests. However, many of the current PWFBs fail to re-direct the vehicle at high speeds due to the inability of the joints to provide appropriate stiffness. The joint mechanism hence plays a crucial role in the performance of a PWFB system at high speed impacts. This paper investigates the desired features of the joint mechanism in a PWFB system that can re-direct vehicles at high speeds, while limiting the lateral displacement to acceptable limits. A rectangular "wall" representative of a 30m long barrier system was modeled and a novel method of joining adjacent road barriers was introduced through appropriate pin-joint connections. The impact response of the barrier "wall" and the vehicle was obtained and the results show that a rotational stiffness of 3000kNm/rad at the joints seems to provide the desired features of the PWFB system to re-direct impacting vehicles and restrict the lateral deflection. These research findings will be useful to safety engineers and road barrier designers in developing a new generation of PWFBs for increased road safety.
Publisher: Elsevier BV
Date: 04-2014
Publisher: Elsevier BV
Date: 08-2009
Publisher: Wiley
Date: 07-1979
Publisher: Informa UK Limited
Date: 20-02-2021
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 12-2011
Publisher: Informa UK Limited
Date: 11-2014
Publisher: Elsevier BV
Date: 12-2015
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 07-2019
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 08-2020
Publisher: SAGE Publications
Date: 18-03-2022
DOI: 10.1177/20414196211062620
Abstract: 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.
Publisher: Hindawi Limited
Date: 08-02-2018
DOI: 10.1002/STC.2148
Publisher: CRC Press
Date: 27-05-2014
DOI: 10.1201/B17063-426
Publisher: Elsevier BV
Date: 07-2016
Publisher: Civil-Comp Press
Date: 2010
DOI: 10.4203/CCP.93.53
Publisher: CRC Press
Date: 21-08-2019
Publisher: Elsevier BV
Date: 11-2023
Publisher: IEEE
Date: 07-2009
Publisher: Elsevier BV
Date: 07-2005
Publisher: Elsevier BV
Date: 08-2016
Publisher: Springer Science and Business Media LLC
Date: 21-03-2013
Publisher: Civil-Comp Press
Date: 2003
DOI: 10.4203/CCP.77.111
Publisher: Elsevier BV
Date: 08-2019
Publisher: Informa UK Limited
Date: 11-10-2016
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 07-2020
Publisher: SAGE Publications
Date: 03-11-2019
Abstract: 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.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 07-1984
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 12-2021
Publisher: Springer Science and Business Media LLC
Date: 04-02-2021
Publisher: Elsevier BV
Date: 10-2017
Publisher: Elsevier BV
Date: 06-2007
Publisher: Elsevier BV
Date: 09-2017
Publisher: Elsevier BV
Date: 1989
Publisher: Informa UK Limited
Date: 09-11-2017
Publisher: Informa UK Limited
Date: 27-11-2019
Publisher: Trans Tech Publications, Ltd.
Date: 06-2020
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.995.123
Abstract: Steel structures are commonly used in seismic regions of the world because of its strength and ductility. However, these structures are still prone to damage during an earthquake. With this risk of seismic damage, the strengthening of steel structures is a major concern in order to resist the dynamic loads resulted from earthquakes. This report investigates the potential for the use of Carbon Fibre Reinforced Polymer (CFRP) to strengthen the rigid steel frame under a real earthquake load. This research will be undertaken using Strand7, a finite element (FE) analysis software. To validate the accuracy of this research, the finite analysis results have been compared to the available experimental study by the Authors. First, both FE models of a five-story bare steel frame and CFRP strengthened steel frame has been developed. Then the predicted numerical results of bare steel frame and CFRP strengthened steel frame under earthquake excitation are compared. The results indicated an increase in the seismic performance of the steel structure due to the strengthened with CFRP. The CFRP strengthened steel frame showed 15% less tip deflection compared to bare steel frame. Further analysis on the strengthening capabilities of higher thickness CFRP was performed to assess the effect of the thickness of CFRP and the higher thickness CFRP showed better seismic performance compare to normal thickness CFRP by reducing 34.38% of tip deflection.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 12-2011
Publisher: Elsevier BV
Date: 2019
Publisher: Informa UK Limited
Date: 24-08-2023
Publisher: American Society of Civil Engineers (ASCE)
Date: 2009
Publisher: American Society of Civil Engineers (ASCE)
Date: 12-2014
Publisher: American Society of Civil Engineers (ASCE)
Date: 12-2007
Publisher: SAGE Publications
Date: 19-09-2018
Abstract: 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.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Elsevier BV
Date: 04-1992
Publisher: Wiley
Date: 28-06-2008
Publisher: SAGE Publications
Date: 05-2012
DOI: 10.1260/1369-4332.15.5.693
Abstract: The study presents a multi-layer genetic algorithm (GA) approach using correlation-based methods to facilitate damage determination for through-truss bridge structures. To begin, the structure's damage-suspicious elements are ided into several groups. In the first GA layer, the damage is initially optimised for all groups using correlation objective function. In the second layer, the groups are combined to larger groups and the optimisation starts over at the normalised point of the first layer result. Then the identification process repeats until reaching the final layer where one group includes all structural elements and only minor optimisations are required to fine tune the final result. Several damage scenarios on a complicated through-truss bridge ex le are nominated to address the proposed approach's effectiveness. Structural modal strain energy has been employed as the variable vector in the correlation function for damage determination. Simulations and comparison with the traditional single-layer optimisation shows that the proposed approach is efficient and feasible for complicated truss bridge structures when the measurement noise is taken into account.
Publisher: Elsevier BV
Date: 09-1993
Publisher: Elsevier BV
Date: 07-1996
Publisher: Trans Tech Publications, Ltd.
Date: 06-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.553.1
Abstract: This paper treats the design and analysis of an energy absorbing system. Experimental tests were conducted on a prototype, and these tests were used to validate a finite element model of the system. The model was then used to analyze the response of the system under dynamic impact loading. The response was compared with that of a similar system consisting of straight circular tubes, empty and foam-filled conical tubes. Three types of such supplementary devices were included in the energy absorbing system to examine the crush behavior and energy absorption capacity when subjected to axial and oblique impact loadings. The findings were used to develop design guidelines and recommendations for the implementation of tapered tubes in energy absorbing systems. To this end, the system was conceptual in form such that it could be adopted for a variety of applications. Nevertheless, for convenience, the approach in this study is to treat the system as a demonstrator car bumper system used to absorb impact energy during minor frontal collisions.
Publisher: Informa UK Limited
Date: 11-2016
Publisher: Elsevier BV
Date: 10-2021
Publisher: American Society of Civil Engineers (ASCE)
Date: 03-1998
Publisher: Wiley
Date: 1984
Publisher: Informa UK Limited
Date: 04-2023
Publisher: ISEC Press
Date: 11-2020
DOI: 10.14455/ISEC.2020.7(2).STR-48
Abstract: 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 ided 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.
Publisher: American Society of Civil Engineers (ASCE)
Date: 10-1984
Publisher: ISEC Press
Date: 11-2020
DOI: 10.14455/ISEC.2020.7(2).STR-47
Abstract: 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.
Publisher: CRC Press
Date: 06-12-2017
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 10-2020
Publisher: SAGE Publications
Date: 07-1989
Abstract: Experiments have been conducted on steel column base plates subjected to eccentric loads and the strain distributions in the base plates at various stages of loading have been determined. The thickness of the base plate and the eccentricity of load have been treated as parameters. Test results for the maximum bending strains, which always occurred at the column–base plate junction on the side of the load, compare reasonably well with those from a finite element analysis. However, the present results for the bending strains in the cantilever portions of the base plates which failed by yielding are greater than those obtained from classical theory, which is, therefore, seen to be conservative for these cases. Longitudinal and lateral strain distributions, strain contour plans, maximum bending strain variation with load, and interaction diagrams are presented and the results discussed. From these results it is evident that flexible base plates, especially when loaded at higher eccentricities, behave somewhat differently from what is assumed in classical methods.
Publisher: Springer Science and Business Media LLC
Date: 27-05-2016
Publisher: Civil-Comp Press
Date: 2013
DOI: 10.4203/CCP.102.12
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier BV
Date: 2020
Publisher: Informa UK Limited
Date: 07-2012
Publisher: Elsevier BV
Date: 12-2020
Publisher: American Society of Civil Engineers (ASCE)
Date: 12-2015
Publisher: Elsevier BV
Date: 1998
Publisher: Springer Singapore
Date: 04-09-2020
Publisher: IEEE
Date: 09-2014
DOI: 10.1109/MCSI.2014.35
Publisher: Elsevier BV
Date: 12-2001
Publisher: American Society of Civil Engineers (ASCE)
Date: 05-1986
Publisher: Informa UK Limited
Date: 08-2014
Publisher: CRC Press
Date: 31-08-2016
Publisher: Springer Science and Business Media LLC
Date: 19-01-2023
DOI: 10.1617/S11527-023-02102-2
Abstract: 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 s les 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.
Publisher: Elsevier BV
Date: 2002
Publisher: World Scientific Pub Co Pte Ltd
Date: 09-2020
DOI: 10.1142/S0219455420420134
Abstract: Irrespective to how well structures were built, they all deteriorate. Herein, deterioration is defined as a slow and continuous reduction of structural performance, which if prolonged can lead to damage. Deterioration occurs due to different factors such as ageing, environmental and operational (E& O) variations including those due to service loads. Structural performance can be defined as load-carrying capacity, deformation capacity, service life and so on. This paper aims to develop an effective method to detect and locate deterioration in the presence of E& O variations and high measurement noise content. For this reason, a novel vibration-based deterioration assessment method is developed. Since deterioration alters the unique vibration characteristics of a structure, it can be identified by tracking the changes in the vibration characteristics. This study uses enhanced autoregressive (AR) time-series models to fit the vibration response data of a structure. Then, the statistical hypotheses of chi-square variance test and two-s le [Formula: see text]-test are applied to the model residuals. To precisely evaluate changes in the vibration characteristics, an integrated deterioration identification (DI) is defined using the calculated statistical hypotheses and a H el filter is used to detect and remove false positive and negative results. Model residual is the difference between the predicted signal from the time series model and the actual measured response data at each time interval. The response data of two numerically simulated case studies of 3-storey and 20-storey reinforced concrete (RC) shear frames contaminated with different noise contents demonstrate the efficacy of the proposed method. Multiple deterioration and damage locations, as well as preventive maintenance actions, are also considered in these case studies. Furthermore, the method was successfully verified utilizing measured data from an experiment carried out on a box-girder bridge (BGB) structure.
Publisher: Elsevier BV
Date: 10-2006
Publisher: Springer Science and Business Media LLC
Date: 02-2018
Publisher: Civil-Comp Press
Date: 2014
DOI: 10.4203/CCP.106.64
Publisher: Informa UK Limited
Date: 11-2015
Publisher: Elsevier BV
Date: 03-1993
Publisher: Elsevier BV
Date: 10-2023
Publisher: Elsevier BV
Date: 06-1992
Publisher: Elsevier BV
Date: 10-2010
Publisher: Elsevier BV
Date: 02-2013
Publisher: Elsevier BV
Date: 1988
Publisher: Wiley
Date: 16-12-2020
DOI: 10.1002/EQE.3238
Publisher: Elsevier BV
Date: 11-2001
Publisher: Informa UK Limited
Date: 2014
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 03-1986
Publisher: Elsevier BV
Date: 1989
Publisher: Elsevier BV
Date: 04-1994
Publisher: Elsevier BV
Date: 10-2018
Publisher: SAGE Publications
Date: 18-01-2019
Abstract: Vibration characteristics of a structure can be used as an indication of its state of structural health as they vary if the structural health is affected by damage. This is the broad principle used in structural health monitoring for vibration-based damage detection of structures. Although most structures are built to have a long life span, they can incur damage due to many reasons. Early damage detection and appropriate retrofitting will enable the continued safe and efficient functioning of structures. This study develops and applies a dual-criteria method based on vibration characteristics to detect and locate damage in arch bridges. Steel arch bridges are one of the most aesthetically pleasing bridge types, which are reasonably popular in Australia and elsewhere. They exhibit three-dimensional and somewhat complex vibration characteristics that may not be suitable for traditional vibration-based damage detection methods. There have been relatively fewer studies on damage detection in these bridge types, and in particular the arch rib and struts, which are important structural components, have received little attention for damage detection. This study will address this research gap and treat the damage detection in the arch bridge structural components using the dual-criteria method to give unambiguous results. The proposed method is first validated by experimental data obtained from testing of a laboratory arch bridge model. The experimental results are also used to validate the modelling techniques and this is followed by damage detection studies on this bridge model as well as on a full-scale long-span arch bridge. Results demonstrate that the proposed dual-criteria method based on the two damage indices can detect and locate damage in the arch rib and vertical columns of deck-type arch bridges with considerable accuracy under a range of damage scenarios using only a few of the early modes of vibration.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Elsevier BV
Date: 05-2015
Publisher: Elsevier BV
Date: 11-2015
Publisher: Elsevier BV
Date: 08-2017
Publisher: Informa UK Limited
Date: 25-03-2008
Start Date: 2010
End Date: 2013
Funder: Australian Research Council
View Funded ActivityStart Date: 2013
End Date: 2015
Funder: Australian Research Council
View Funded ActivityStart Date: 2016
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 2015
End Date: 2018
Funder: Australian Research Council
View Funded ActivityStart Date: 2013
End Date: 2013
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2014
Funder: Australian Research Council
View Funded Activity