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 Subjects -> ENGINEERING (Total: 2410 journals)     - CHEMICAL ENGINEERING (206 journals)    - CIVIL ENGINEERING (201 journals)    - ELECTRICAL ENGINEERING (112 journals)    - ENGINEERING (1268 journals)    - ENGINEERING MECHANICS AND MATERIALS (392 journals)    - HYDRAULIC ENGINEERING (57 journals)    - INDUSTRIAL ENGINEERING (78 journals)    - MECHANICAL ENGINEERING (96 journals) CIVIL ENGINEERING (201 journals)                  1 2 | Last
 Showing 1 - 200 of 201 Journals sorted alphabetically ACI Structural Journal       (Followers: 20) Acta Polytechnica : Journal of Advanced Engineering       (Followers: 3) Acta Structilia : Journal for the Physical and Development Sciences       (Followers: 2) Advances in Civil Engineering       (Followers: 39) Advances in Structural Engineering       (Followers: 32) Agregat       (Followers: 1) Ambiente Construído       (Followers: 1) American Journal of Civil Engineering and Architecture       (Followers: 34) Architectural Engineering       (Followers: 5) Archives of Civil and Mechanical Engineering       (Followers: 3) Archives of Civil Engineering       (Followers: 12) Archives of Hydro-Engineering and Environmental Mechanics       (Followers: 2) ATBU Journal of Environmental Technology       (Followers: 4) Australian Journal of Structural Engineering       (Followers: 6) Baltic Journal of Road and Bridge Engineering       (Followers: 1) BER : Building and Construction : Full Survey       (Followers: 10) BER : Building Contractors' Survey       (Followers: 2) BER : Building Sub-Contractors' Survey       (Followers: 2) BER : Survey of Business Conditions in Building and Construction : An Executive Summary       (Followers: 3) Bioinspired Materials       (Followers: 5) Bridge Structures : Assessment, Design and Construction       (Followers: 14) Building & Management       (Followers: 1) Building and Environment       (Followers: 15) Building Women Built Environment Project and Asset Management       (Followers: 14) Bulletin of Pridniprovsk State Academy of Civil Engineering and Architecture       (Followers: 6) Canadian Journal of Civil Engineering       (Followers: 13) Case Studies in Engineering Failure Analysis       (Followers: 6) Case Studies in Nondestructive Testing and Evaluation       (Followers: 11) Case Studies in Structural Engineering       (Followers: 9) Cement and Concrete Composites       (Followers: 20) Challenge Journal of Concrete Research Letters       (Followers: 3) Challenge Journal of Structural Mechanics       (Followers: 5) Change Over Time       (Followers: 2) Civil and Environmental Engineering       (Followers: 8) Civil and Environmental Engineering Reports       (Followers: 8) Civil and Environmental Research       (Followers: 17) Civil Engineering = Siviele Ingenieurswese       (Followers: 4) Civil Engineering and Architecture       (Followers: 23) Civil Engineering and Environmental Systems       (Followers: 3) Civil Engineering and Technology       (Followers: 12) Civil Engineering Dimension       (Followers: 11) Civil Engineering Infrastructures Journal       (Followers: 1) Cohesion and Structure       (Followers: 2) Composite Structures       (Followers: 286) Computer-aided Civil and Infrastructure Engineering       (Followers: 11) Computers & Structures       (Followers: 38) Concrete Research Letters       (Followers: 7) Construction Economics and Building       (Followers: 4) Construction Engineering       (Followers: 11) Construction Management and Economics       (Followers: 21) Constructive Approximation Curved and Layered Structures       (Followers: 3) DFI Journal : The Journal of the Deep Foundations Institute       (Followers: 1) Earthquake Engineering and Structural Dynamics       (Followers: 17) Enfoque UTE       (Followers: 4) Engineering Project Organization Journal       (Followers: 7) Engineering Structures       (Followers: 13) Engineering Structures and Technologies       (Followers: 2) Engineering, Construction and Architectural Management       (Followers: 10) Environmental Geotechnics       (Followers: 5) European Journal of Environmental and Civil Engineering       (Followers: 9) Fatigue & Fracture of Engineering Materials and Structures       (Followers: 19) Frontiers in Built Environment Frontiers of Structural and Civil Engineering       (Followers: 6) Geomaterials       (Followers: 3) Geosystem Engineering       (Followers: 1) Geotechnik       (Followers: 3) Géotechnique Letters       (Followers: 7) GISAP : Technical Sciences, Construction and Architecture HBRC Journal       (Followers: 2) Hormigón y Acero HVAC&R Research Indonesian Journal of Urban and Environmental Technology Indoor and Built Environment       (Followers: 2) Infrastructure Asset Management       (Followers: 3) Infrastructures Ingenio Magno       (Followers: 1) Insight - 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 Journal of Civil Structural Health MonitoringJournal Prestige (SJR): 0.727 Citation Impact (citeScore): 2Number of Followers: 4      Hybrid journal (It can contain Open Access articles) ISSN (Print) 2190-5452 - ISSN (Online) 2190-5479 Published by Springer-Verlag  [2348 journals]
• Scour depth estimation in a balanced cantilever bridge with deteriorated
central hinges based on natural frequencies: field measurements,
methodology for estimation and verification
• Authors: M. S. I. Choudhury; Y. Matsumoto; A. F. M. S. Amin
Abstract: A scheme based on field measurements of vibrations is proposed for estimating the scour depths of a multi-span balanced cantilever bridge resting on foundations embedded in soft soil. Field measurements of ambient vibrations using velocity sensors indicated elongated periods of vibration in the transverse direction at the pier tops due to scour underneath. The modal properties were identified using the Eigensystem Realization Algorithm. The unknown spring constants of the central hinges were determined to represent the deteriorated performance of the bridge superstructure under no-scour benchmark conditions from a finite element model incorporating soft soil conditions. A single set of spring constants compatible with the measured natural frequencies was thus identified for the transverse movement of the central hinges. The strong dependence of the transverse bending mode of the pier and weak dependence of the longitudinal bending mode of the pier on scour phenomena were clearly observed. The observed relationships between the scour depth and natural frequency were sensitive to soft soil conditions in both modes. The estimated spring constants representing soft soil were used to assess the unknown scour depths in the pier foundations suffering from scour. Independent bathymetric surveys verified the general applicability of the proposed scheme for estimating the scour depths around bridges of this type within reasonable limits.
PubDate: 2018-08-14
DOI: 10.1007/s13349-018-0300-9

• Development of a hybrid SHM of cable bridges based on the mixed
probability density function
• Authors: Yuhee Kim; Jong-chil Park; Soobong Shin
Abstract: The previous studies on structural health monitoring (SHM) of cable bridges have assessed the health of bridges by a deterministic way or by assuming a calculated health index as a normal distribution. However, various case studies have shown that the health index obtained from field measurement data does not generate a Gaussian distribution due to various factors. In this study, a new mixed probability density function (PDF) is proposed for each local health index based on the findings. The joint PDF for each type of data is determined from the obtained local PDFs. The hybrid index of a bridge is then determined by a combination of local indices. The impact of local damage to the overall health of a bridge is evaluated by taking into account the weight of the sensor type and the weight of the sensor location related to the importance of the member. The proposed hybrid SHM has been verified through a simulation study on a truss structure and by applying it to an existing cable-stayed bridge.
PubDate: 2018-08-06
DOI: 10.1007/s13349-018-0298-z

• Crack detection in prestressed concrete structures by measuring their
natural frequencies
• Authors: G. D. Ercolani; D. H. Felix; N. F. Ortega
Abstract: When inspecting the health of a civil structure, it is important to have efficient techniques to detect the possible presence of structural damage. This work deals with the detection of damage in prestressed concrete structures, which are widely used in road bridges and long span slabs, among others. Concrete structures can be affected by different pathologies, with the transverse cracks beingone of the most dangerous damages, since they involve a localized reduction of the flexural rigidity of the structure. Such cracks change both the static and dynamic behavior of the structure. In this paper, an inverse method of damage detection is applied on two experimental beams built in the laboratory, from the measurement of the first three natural frequencies of vibration. An algorithm for solving the system of equations has been developed by the authors. Explicit equations were obtained to calculate both the crack position and its depth. The predicted damages by the algorithm have been in good agreement with the real damages of the experimental models. An important aspect of this methodology for crack detection is the simplicity of its experimental implementation.
PubDate: 2018-08-01
DOI: 10.1007/s13349-018-0295-2

• Transmissibility-based damage detection using angular velocity versus
acceleration
• Authors: Samer Al-Jailawi; Salam Rahmatalla
Abstract: This work presents a new damage-detection approach for structural systems that uses the transmissibility and coherence functions of the output angular velocity between two points on the structure, at locations where damage may occur, to generate a damage index as a metric of the changes in the dynamic integrity of the structure. The efficacy of the proposed damage index as compared to that based on the traditional transmissibility of acceleration was tested on straight beams. The experimental and numerical results showed that the new damage index outperformed that based on acceleration by multiple levels in terms of detecting and localizing damage. The experimental results also showed that the proposed damage index using gyroscopes was much less sensitive to the environmental acoustic noises under consideration (65–85 dB) when compared with the damage index based on the acceleration.
PubDate: 2018-07-26
DOI: 10.1007/s13349-018-0297-0

• Damage assessment due to pounding between adjacent structures with equal
and unequal heights
• Authors: Rajaram Chenna; Pradeep Kumar Ramancharla
Abstract: Structural pounding may occur between two structures or at different parts of the same building during ground motions. Among all the structural damages, structural pounding has been commonly observed during several earthquakes in the past, which have lead to minor damage till complete collapse of the structure. The main focus of this paper is to study pounding responses and impact effects on structures subjected to ground motions. It is observed from the study that the response of stiff structure is more than flexible structure at dominant period of ground motion, irrespective of equal and unequal heights. If the structures vibrate at a non-dominant period of ground motion, then the response of flexible structure is observed more than the stiff structure.
PubDate: 2018-07-19
DOI: 10.1007/s13349-018-0296-1

• Experimental and numerical dynamic structural analysis of footbridges when
• Authors: Irwing Aguiar Ribeiro da Silva; José Guilherme Santos da Silva
Abstract: This research work aims to investigate the dynamic structural behaviour and assess the human comfort of footbridges, when subjected to pedestrian walking, based on experimental tests and tuning of finite element model. This way, the test structure is related to a real pedestrian footbridge, located at the Osvaldo Aranha Street, route of great importance and so very heavy traffic of vehicles along the day, next to the new Maracanã Stadium, in the city of Rio de Janeiro/RJ, Brazil. The investigated footbridge presents two spans with length equal to 29.5 and 24 m, respectively, and a total length of 53.5 m. Initially, to identify and assess the global dynamic structural behaviour of the structural model an operational modal analysis (OMA) was performed on the investigated footbridge. After that, several forced vibration tests were performed on the footbridge, considering the pedestrians walking with different step frequencies. In sequence, a finite element model was developed based on the ANSYS computational program. This model was used for the calibration of results, obtained based on the footbridge experimental monitoring. Finally, a human comfort assessment was performed, based on the comparisons between the results (peak accelerations), of the dynamic experimental monitoring and the recommendations provided by design guides HIVOSS and SÉTRA.
PubDate: 2018-07-10
DOI: 10.1007/s13349-018-0294-3

• Structural health monitoring techniques implemented on IASC–ASCE
benchmark problem: a review
• Authors: Swagato Das; Purnachandra Saha
Abstract: Various structural health monitoring techniques have been developed over the years. Due to the lack of a common platform to test the efficiency of these methods, the damage analysis models have been tested on different structures selected according to the choice of researches. Therefore, perfect comparison among the models was not possible. In light of this event, a benchmark structure was developed providing a common ground to analyse the effectiveness of the damage detection strategies. This structural damage analysis consists of different damage patterns, major damages and minor damages. The damage detection algorithms were tested for the detection of these different damage patterns and the effectiveness against noise contamination. Also the amount of data required for the algorithms to effectively detect damage was also recorded, which indicated the efficiency of the method applied. The paper deals with the application of different damage detection techniques on the ASCE benchmark Phase-I and Phase-II structure and studies their efficiency against the other structures. A brief comparison has been made among different damage detection models such as Bayesian model, neural network, autoregressive models, and model update. These methods have been successfully implemented on the benchmark structure and their efficiencies have been measured in terms of noise contamination, the amount of data required to measure the damage and the detection of damage (major and minor). Out of all the techniques discussed, model update technique, wavelet approach, autoregressive technique, convolution neural network and synchrosqueezed wavelet transform have proved to a robust damage analysing tool.
PubDate: 2018-07-02
DOI: 10.1007/s13349-018-0292-5

• Study on the dynamic properties of a suspended bridge using monocular
digital photography to monitor the bridge dynamic deformation
• Authors: Guojian Zhang; Guangli Guo; Long Li; Chengxin Yu
Abstract: This study makes use of monocular digital photography, based on the IM-STBP (image matching-space time baseline parallax) method, to monitor bridge dynamic deformation to study bridge dynamic properties. A bridge was first photographed when traffic light was red (i.e., when the bridge was not influenced by dynamic vehicle load) to generate the zero image (a.k.a. the reference image), and then photographed every 3 s when the traffic light was green (i.e., when the bridge was influenced by dynamic vehicle load) to produce image sequences as successive images. Relative deformation values of deformation points were obtained based on the IM-STBP method. The results show that the measurement accuracy of the IM-STBP method reaches a sub-pixel level (0.445, 0.470 and 0.705 pixels in the X, Z and comprehensive directions, respectively) and that maximal deflections of the bridge monitored by cameras 1 and 3 (37.22 and 47.40 mm, respectively) are within bridge deflection tolerance (75 mm). The monocular digital photography presented in this study has proved effective in monitoring bridge dynamic deformation even when the photographing direction is not perpendicular to the bridge plane and useful in assessing the situation of a bridge by monitoring the instantaneous dynamic global deformation of a bridge when the traffic light is green. Deformation curves in real time can also provide warning of any possible danger on the bridge. These global deformation curves of a bridge play a key role in studying the dynamic properties of a bridge influenced by dynamic vehicle load.
PubDate: 2018-07-02
DOI: 10.1007/s13349-018-0293-4

• Noise isolation with phononic crystals to enhance fatigue crack growth
detection using acoustic emission
• Authors: Minoo Kabir; Amir Mostavi; Didem Ozevin
Abstract: The background noise imposes difficulties in monitoring crack activities in real-time monitoring of structures using the acoustic emission (AE) method. Here, a two-dimensional phononic crystal (PC) is designed to enhance fatigue crack growth detection capability of acoustic emission technique in plate-like structures, such that a single AE sensor is sufficient to monitor the crack activity. PCs, also known as acoustic metamaterials, are artificial composite, man-made periodic systems creating new responses through physical constraints in the constituent materials such that certain frequencies are prohibited by local the resonance of the periodic system. The integration of PC design with AE method can be utilized to block unwanted noise signals and enhance the crack detection ability of the AE method. The proposed PC structure to block certain frequencies is numerically studied using COMSOL Multiphysics software through applying two approaches: the unit cell analysis and the transmission loss. It is concluded that the primary reason of the band gap formation through the designed PC structure is the local resonance phenomenon. The final geometry is selected to provide a band gap near 150 kHz, which is a common frequency to monitor crack growth in metallic structures. The stubs forming the PC structure are placed on the compact specimen periodically, except along the crack growth path and sensor position, to block the friction emissions coming from the grip locations. The performance of the designed PC structure is demonstrated experimentally through the fatigue testing of aluminum standard compact tension specimens. The cumulative numbers of hits and AE energy obtained from the specimen integrated with the PC structure demonstrate the successful implementation of noise blocking in the AE testing of detecting active cracks.
PubDate: 2018-06-23
DOI: 10.1007/s13349-018-0291-6

• Structural performance monitoring of buried pipelines using distributed
fiber optic sensors
• Authors: Xin Feng; Yang Han; Zihao Wang; Hongfei Liu
Abstract: In this study, a method involving the use of distributed fiber optic temperature and strain sensors is presented to quantitatively assess the structural performance for buried pipelines by considering both longitudinal bending load and axial thermal load. The monitoring scheme of distributed strain and temperature sensors is proposed based on the pipeline structural analysis, and the assessment approach is formulated using the distributed monitoring data. The time-spatial variation in the bending strain and temperature of the burial pipelines are monitored using distributed fiber optic sensors. The structural performance of the pipeline is then assessed with the monitored data in conjunction with the pipe parameters and internal pressure. A field application was performed on a buried gas pipeline to investigate the availability of the proposed method and the results from the site application demonstrate that the proposed method effectively assesses the structural performance of the burial pipelines with the distributed strain and temperature data.
PubDate: 2018-06-20
DOI: 10.1007/s13349-018-0286-3

• Intelligent tensioning control and management integrated system for
high-speed railway pre-stressed concrete beam
• Authors: Yi Zhuo
Abstract: The tension force pre-stressing of most pre-stressed concrete beams (BPS) for high-speed railways in China is currently performed using a traditional manual operation method, leading to low efficiency, poor precision, a complicated operation, and uncontrollable calibration authenticity, among other factors. This paper presents an intelligent tension control and management system for a BPS, including the hardware equipment and corresponding matching software system. In accordance with the current scenario in pre-stressed tension construction, intelligent tensioning control station, tensioning jacks, and other hardware equipment, matching BPS software has been developed. This system is based on radio frequency identification technology, cloud technology, big data technology, the building of a set platform regarding the pre-stressed tension construction control, process management, supervision, and implementation of a railway precast beam. The system achieves automation, information, visualization and remote of the entire process of pre-stressed tension construction, and lays the foundation for the popularization of the Internet of Things technology within railways in China.
PubDate: 2018-06-16
DOI: 10.1007/s13349-018-0288-1

• Evaluating the damage degree of cracking in facades using infrared
thermography
• Authors: Elton Bauer; Patrícia Mota Milhomem; Luiz Augusto Gimenez Aidar
Abstract: The study of facade cracking is of great importance in the investigation of pathologies and degradation, as well as in the rehabilitation processes of buildings. Cracking is one of the major defects in facades; so assessing damage severity is necessary to define the best maintenance and rehabilitation strategies. The infrared thermography has been increasingly used as an inspection technique to identify and map facade defects and their severity. The use of hygrothermal simulation to understand the dynamics of the heat flux allows to observe important references that can help in the interpretation of the thermogram under different heating or cooling conditions. This study investigates the use of the quantitative passive thermography to measure the damage degree of cracks in a building facade. The crack depth was evaluated by the Delta-T values investigated in the three cracked regions. For the width, the variation of the studied temperature in a line transversal to the crack was used. The analysis was performed at a distance of 33 m from the facade. The conclusions corroborated the importance of the hygrothermal simulation as a pre-thermography technique, which made it possible to limit the period of investigation focusing on the phenomena of interest. It is also observed that it is possible to obtain quantitative values of the degree of damage by thermographic investigation. The measurement of the damage degree, in turn, brings important contribution to the application of the inspection technique.
PubDate: 2018-06-13
DOI: 10.1007/s13349-018-0289-0

• Estimation of scour depth at bridges with complex pier foundations using
support vector regression integrated with feature selection
• Authors: Nhat-Duc Hoang; Kuo-Wei Liao; Xuan-Linh Tran
Abstract: This study aims at establishing machine learning models based on the support vector regression (SVR) for estimating local scour around complex piers under steady clear-water condition. A data set consisting of scour depth measurement cases has been collected to construct the prediction models. The data set includes eight influencing factors that consider aspects of pier geometry, flow property, and river bed material. Moreover, to enhance the performance of the SVR model, filter and wrapper feature selection strategies are used. The research finding is that all feature selection approaches can help to improve the prediction accuracy compared with the SVR model that uses all available features. Notably, the feature selection method based on the variable neighborhood search (VNS) algorithm achieves the best performance (MAPE = 21.65%, R2 = 0.85). Accordingly, the prediction model produced by SVR and VNS can be useful for assisting decision makers in the task of structural health monitoring as well as the design phase of bridges.
PubDate: 2018-06-02
DOI: 10.1007/s13349-018-0287-2

• Verification of the applicability of the Gaussian mixture modelling for
damage identification in reinforced concrete structures using acoustic
emission testing
• Authors: R. Vidya Sagar
Abstract: This article presents an experimental study on verification of the applicability of Gaussian mixture modelling (GMM) algorithm of acoustic emissions for damage identification in reinforced concrete (RC) structures. Eight RC-flanged beam specimens with different properties were tested subjected to flexural loading. An incremental cyclic load was applied on RC-flanged beam specimens till failure, and simultaneously, the released acoustic emissions (AE) were recorded. It may be required to study crack classification in RC structures, because crack classification studies are useful to predict the structural performance and subsequently to implement the appropriate structural rehabilitation methods. AE belonging to tensile cracking and shear cracking can be studied by a probabilistic approach. It was observed that the line separating the AE clusters belonging to tensile and shear cracks was shifting towards a higher rise angle as the specimen is reaching collapse stage. This observation indicates dominance of shear cracks near the collapse stage. At the loading cycle where yielding occurred in the test specimen obtained by using GMM algorithm for AE, the load cycle entered into heavy damage zone is almost same as per NDIS-2421 damage assessment chart. The results obtained by both GMM algorithms for AE and NDIS-2421 criterion to evaluate the damage in the RC-flanged beams were compared and discussed.
PubDate: 2018-06-01
DOI: 10.1007/s13349-018-0284-5

• Bridge inspection: human performance, unmanned aerial systems and
automation
• Authors: Sattar Dorafshan; Marc Maguire
Abstract: Unmanned aerial systems (UASs) have become of considerable private and commercial interest for a variety of jobs and entertainment in the past 10 years. This paper is a literature review of the state of practice for the United States bridge inspection programs and outlines how automated and unmanned bridge inspections can be made suitable for present and future needs. At its best, current technology limits UAS use to an assistive tool for the inspector to perform a bridge inspection faster, safer, and without traffic closure. The major challenges for UASs are satisfying restrictive Federal Aviation Administration regulations, control issues in a GPS-denied environment, pilot expenses and availability, time and cost allocated to tuning, maintenance, post-processing time, and acceptance of the collected data by bridge owners. Using UASs with self-navigation abilities and improving image-processing algorithms to provide results near real-time could revolutionize the bridge inspection industry by providing accurate, multi-use, autonomous three-dimensional models and damage identification.
PubDate: 2018-05-21
DOI: 10.1007/s13349-018-0285-4

• Drive-by damage detection with a TSD and time-shifted curvature
• Authors: Jennifer C. Keenahan; Eugene J. OBrien
Abstract: ‘Drive-by’ damage detection is the concept of using sensors on a passing vehicle to detect damage in a bridge. The newly developed traffic speed deflectometer (TSD) is a device used for pavement velocity/deflection measurements and is investigated here in numerical simulations as a means of bridge damage detection. A TSD vehicle model containing five displacement sensors is simulated crossing a simply supported finite element beam containing damage simulated as a loss in stiffness of one of the elements. Time-shifted curvature is derived from the displacements and is proposed as a novel damage indicator, which removes the influence of the road profile and all vehicle motions except for pitch. Results show that the time-shifted curvature can be reliably used as a damage indicator in the presence of noise and changes in transverse position of the vehicle on the bridge.
PubDate: 2018-05-11
DOI: 10.1007/s13349-018-0280-9

• Population-based structural identification for reserve-capacity assessment
of existing bridges
• Authors: Marco Proverbio; Didier G. Vernay; Ian F. C. Smith
Abstract: Transportation networks provide an essential contribution to addressing the needs of reliable and safe mobility in urban environments. The core of these networks is made up of infrastructure such as roads and bridges that often, have not been designed to meet current needs. Optimal management requires an accurate knowledge of how existing structures behave. This helps avoid unnecessary replacement and expensive interventions when cheaper and more sustainable alternatives are available. Structural-model updating takes advantage of measurements and more qualitative observations to identify suitable behaviour model classes and values for parameters that influence real behaviour. Error domain model falsification (EDMF) has been proposed as a robust population-based methodology to identify sets of models by comparing finite-element model predictions with measurements at sensor locations. This paper introduces a methodology, which is compatible with EDMF, to assess the reserve capacity of bridges for serviceability and ultimate limit states. A case study—the structural identification of a reinforced-concrete bridge in Singapore—illustrates the framework developed for the estimation of reserve capacity. Several analyses with increasing levels of model detail using design and updated values of relevant parameters are presented. Traffic-load specifications of design-stage codes (British Code—1978) and current codes (Eurocodes) are compared. Results show that typical conservative practices carried out during design and construction have led to an as-built reserve capacity of 60%. A large proportion of the as-built reserve capacity has been exploited to accommodate dramatically increased values of traffic-load specifications that are provided by current Singapore codes which have caused a reduction in reserve capacity to 20%. Such a reduction may be less significant in countries where code specifications have not changed as much. Finally, it is shown that advanced methods of analysis and assessment are more suitable than design-stage approaches to quantify the reserve capacity.
PubDate: 2018-04-25
DOI: 10.1007/s13349-018-0283-6

• Making good use of structural health monitoring systems of long-span
cable-supported bridges
• Authors: You-Lin Xu
Abstract: Many long-span cable-supported bridges have emerged in recent years, but are exposed to harsh environment conditions. The installation of long-term structural health monitoring (SHM) systems to the bridges has become a trend to monitor their loading conditions, assess their performance, detect their damage, and guide their maintenance with the utmost goals of ensuring their functionality, safety and sustainability. Nevertheless, it is not very clear how to make good use of SHM systems toward these goals. This paper takes the Tsing Ma suspension bridge in Hong Kong as an example and recapitulates the relevant works done by the author and his colleagues and students in the past 20 years to manifest how the SHM system installed in the bridge has been utilized since 1997. The SHM system installed in the bridge is briefly introduced first. How to use the SHM system for investigating highway loading, railway loading, wind characteristics, and temperature effects is then presented. Identification of time-varying natural frequencies and modal damping ratio of the bridge under strong winds using the data recorded by the SHM system is also demonstrated. Toward the performance assessment and damage detection of the bridge, SHM system-based computer simulation and damage assessment are targeted and some typical examples are given. The establishment of SHM system-based bridge rating system for bridge maintenance is also briefly introduced.
PubDate: 2018-04-25
DOI: 10.1007/s13349-018-0279-2

• Structural response of a cable-stayed bridge subjected to lateral seismic
excitations
Abstract: Cable-stayed bridges are structurally efficient and offer cost effective solutions in medium to large-span crossings. The study reported in this article aimed at determining the behavior of a typical cable-stayed bridge when subjected to lateral earthquake excitations. A hybrid analytical–experimental technique is introduced to experimentally simulate the earthquake excitations on the bridge. In this technique, displacement time history of the bridge mid-span was first obtained analytically by exciting the bridge using the earthquake acceleration records. To experimentally simulate the earthquake excitations, these displacements were applied on a $$\frac{1}{60}$$ scale model of a single plane cable-stayed bridge using a displacement controlled shaker. The efficiency of this technique was evaluated by comparing the experimental versus analytical response in terms of dynamic characteristics and displacement responses of the bridge. The analytical response of the bridge served as a verification tool for validation of key response parameters of the full-scale bridge. These parameters included forces in cables, strains and stresses in the deck, and moments and shear forces acting on pylons in the transverse direction.
PubDate: 2018-04-20
DOI: 10.1007/s13349-018-0282-7

• Detection of speed and axle configuration of moving vehicles using
acoustic emission
• Authors: B. Algohi; A. Mufti; D. Thomson
Abstract: Axle detection is a critical monitoring process that needs to be implemented on bridges so that the number of axles of crossing vehicles can be determined. Most bridge design codes specify bridge design loads based on certain trucks configurations. Reviewing and updating bridge design codes depend on an accurate measurement of the nature of the loads being transported across bridges. Measurement of axle loads and configuration of trucks is also essential for bridge load regulation and enforcement. In this paper, a new method is proposed for the accurate detection of velocity, number of axles, and configuration of moving vehicles on bridges. The proposed method uses the acoustic signals emitted when the tires of moving vehicles hit bridge expansion joints and was tested on a bridge in Morris, Manitoba, Canada. It was discovered that the proposed method accurately predicts the velocity, number of axles, and configuration of moving vehicles on bridges.
PubDate: 2018-04-09
DOI: 10.1007/s13349-018-0281-8

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