Wael Zatar

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Charalampos Vasilatos

National & Kapodistrian University of Athens

Paulo Emanuel T F Fonseca

Universidade de Lisboa

Vasilios Melfos

Aristotle University of Thessaloniki

Jean-Philippe Goiran

Université Lyon

Alexei Abramov

Russian Academy of Sciences, Zoological Institute

Laurent Bruxelles

INRAP, Institut National de Recherches Archéologiques Préventives

Johan Edwart L. Hutabarat

Institut Teknologi Nasional Yogyakarta (ITNY)

Björn Nilsson

Lund University

Michel Gregoire

Observatoire Midi-Pyrénées, Université de Toulouse III Paul Sabatier

Polina Lemenkova

Università di Bologna

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Papers by Wael Zatar

Non-Destructive Testing and Evaluation of Timber and Steel H-Piles

Experimental Investigation of Post-Tensioned Anchored Trunnion Rods of Navigation Structures

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Assessment technologies of rail systems’ structural adequacy — A review from mechanical engineering perspectives

Science Progress, Apr 1, 2022

Seismic Risk Assessment of Priority Bridges along I-24 in Western Kentucky

Sixth National Seismic Conference on Bridges and HighwaysMultidisciplinary Center for Earthquake Engineering ResearchSouth Carolina Department of TransportationFederal Highway AdministrationTransportation Research Board, 2008

Interstate-24 (I-24) in western Kentucky lies just east of the New Madrid Seismic Zone. Seismolog... more Interstate-24 (I-24) in western Kentucky lies just east of the New Madrid Seismic Zone. Seismologists believe that there is a high probability of a major earthquake event to hit the area in the near future. I-24 is a high priority and emergency route that has to remain functional and operational during major earthquake events. Two parallel long span bridges lie along I-24 in western Kentucky and cross the Tennessee River. Two other parallel bridges lie along I-24 in western Kentucky and cross the Cumberland River. Due to the importance of the four existing bridges, it was decided to carry out seismic evaluation and risk assessment studies. The bridges were evaluated for the 250-year and the 500-year seismic events. The following tasks were carried out to judge the structural integrity and the seismic vulnerability of the bridges: (1) field testing of the main long spans; (2) finite element modeling and calibration; (3) time-history seismic response analysis; and (4) seismic evaluation for the main spans and the approach spans. Deficiencies of the seismic performance of the four bridges at the Tennessee River and at the Cumberland River crossings were identified, and retrofit recommendations were provided.

Seismic Evaluation and Ranking of Bridge Embankments along I-24 in Western Kentucky

The contents of this report reflect the views of the authors who are responsible for the facts an... more The contents of this report reflect the views of the authors who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky, the Kentucky Transportation Cabinet, nor the Federal Highway Administration. This report does not constitute a standard, specification or regulation. The inclusion of manufacturer names or trade names are for identification purposes and are not to be considered as endorsement.

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Substructured Pseudodynamic and Statically Reversed Cyclic Loading Tests of Prestressed Concrete Viaduct Structures

Transportation Research Board 85th Annual MeetingTransportation Research Board, 2006

Prestressed concrete viaduct structures were commonly used over the past two decades for the cons... more Prestressed concrete viaduct structures were commonly used over the past two decades for the construction of many highways and railways. The objective of this study was to clarify the inelastic response behavior of partially prestressed concrete viaduct structures during severe earthquake excitations. A study that includes experimental and analytical phases was carried out. Small-scaled models were employed so as to represent actual viaduct structures. Specimens representing the PC girders of the viaduct structures were tested experimentally. Two testing techniques were employed in the experimental phase of the study. The first technique was a statically reversed cyclic loading test. The objective of the statically reversed cyclic loading test was to study the inelastic response behavior of the PC girders and to obtain the hysteretic-load deformational characteristics. The sub-structured pseudo-dynamic testing technique was implemented as the second testing technique. During the sub-structured pseudo-dynamic test, the PC girder was tested experimentally and the RC columns of the viaduct structure were simulated analytically. An amplified excitation of the 1995 Hyogo Ken Nanbu earthquake was used. Response analyses for the viaduct model in terms of hysteretic moment-rotation curves and time-histories were carried out. The plastic deformability expressed in terms of the ductility factor and the dissipated energy was examined. A comparison between the experimental results and results obtained from response analyses was made. A good agreement between the experimental and analytical results was found. The study revealed that not only the RC columns but also the PC girders may undergo extensive damage during severe earthquake excitations.

Preliminary Seismic Evaluation and Ranking of Bridges along I-24 in Western Kentucky

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Site Investigation of Bridges along I-24 in Western Kentucky

Determination of the seismic risk of the I-24 bridges requires evaluating the current condition o... more Determination of the seismic risk of the I-24 bridges requires evaluating the current condition of all individual elements of the bridges. All bridges along the I-24 were visually inspected, pictured, and the records were stored in a database. Data of the visual inspection and the pictures were combined to form the completed site inspection forms of the I-24 bridges. Main visually observed deficiencies of the bridge elements were pointed out. The site inspection forms of all bridges on/over the I-24 in western Kentucky are used together with the bridge inventory to obtain different statistical figures regarding the characteristics of the bridges. The site inspection forms are considered to be a source that provides images of the existing conditions, assists in pre-earthquake preparation plans, and forms the basis to develop post-earthquake emergency response, inspection, and evaluation plans.

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Feasibility of Estimating Commodity Flows on Highways with Existing and Emerging Technologies

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Seismic Evaluation of the Cumberland River Bridges on I-24 in Western Kentucky

The main objective of this study is to assess the structural integrity of the I-24 parallel bridg... more The main objective of this study is to assess the structural integrity of the I-24 parallel bridges at the Cumberland River crossing in western Kentucky. Due to its importance, the bridge is evaluated for the 250-year event and the maximum credible 500-year event. The scope of the work included: 1) Field testing of the main bridge; 2) Finite element modeling and calibration; 3) Time-history seismic response analysis for the main spans; and 4) Seismic evaluation for both the main and the approach spans. The seismic analysis for the 250-year event indicates that the main spans of the bridge can resist the event without yielding or loss-of-span at the supports. However, the anchor bolts on some of the piers are expected to fail in shear. Retrofitting measures are recommended. The seismic analysis for the 500-year event shows that few members of the main spans would yield due to the event. Also, the capacity of the bearing shear bolts of few piers of the main and approach spans are exceeded, and retrofitting measures are recommended.

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Criteria for Predicting Scour of Erodible Rock in West Virginia

This research project was conducted to characterize the hydraulic scour of rock at 15 selected br... more This research project was conducted to characterize the hydraulic scour of rock at 15 selected bridge sites in West Virginia (at least one site in each of West Virginia Division of Highway's (WVDOH’s) ten districts). The study assessed the applicability of a recently-developed rock scour prediction technique to the types of rock and scour conditions found in West Virginia, and identified techniques that can be used to better characterize scour potential at existing and proposed bridge locations. Foundation inspection, rock coring and sample collection, and measurement of scour depth at all sites led to a determination of each site’s mode of scour and enabled modified slake durability testing to develop a median Geotechnical Scour Number (GSN) for rock encountered at each bridge site. Flow conditions over time were assessed for each site using stream gage data where such data was available (three sites), and watershed models, coupled with probabilistic characterizations of precipitation, where stream gage data was not available (12 sites). Scour depth observed at each site, coupled with estimates of Cumulative Excess Stream Power, enabled the calculation of a Scour Number at each site. The scour prediction method applied for this project is designed specifically for sites characterized by abrasion of degradable rock. Ideally, this mode of scour can be confirmed before the method is applied, but in cases where the mode of scour is not clear from field data, or where more than one mode of scour is operating at the same site, this may not be possible or practical. For sites affected only by abrasion, Scour Number and GSN should be consistent, allowing GSN to be used as a predictive measure of scour potential. In this project, however, Scour Number and GSN deviated considerably. The Scour Number/GSN (which, if GSN is to be predictive should have been near 1.0) varied from 3.9 – 17,000. The quarrying mode of scour, where durable, fractured rock is plucked away in discrete scour events from its original location, was evident to varying degrees at 14 of the 15 project sites, and explains why the GSN-centered approach of predicting rock scour, which is contingent on the progressive wear (i.e., abrasion) of non-durable degradable rock, did not apply to the data collected. In those cases where the mode of scour was unclear from field evidence, the lack of agreement between Scour Number and GSN served as indirect confirmation that scour was significantly or wholly attributable to quarrying and not abrasion. Though methodologies have been proposed to attempt scour depth prediction for quarrying , such methods require a comprehensive characterization of the distribution of block shape and dimensions, joint angle, block density, block protrusion, and flow field conditions, and applying such an approach was beyond the scope of this project. Other likely contributors to differences between Scour Number and GSN include uncertainties inherent in probabilistic characterizations of flow, and variations in the flow field along abutments (in contrast to the relative simplicity of the flow field at a pier). Results lead to the conclusion that GSN may not be a universally-appropriate tool for predicting rock scour across the range of rock types and flow conditions found in West Virginia, particularly in view of widespread quarrying of durable rock at the project sites. A Scour Mode Decision Tree was developed to aid in identifying scour mode at future sites where scour assessments are performed, and a method was developed for generating a probabilistic estimation of Average Annual Cumulative Effective Stream Power.

Interactive Bridge Inspection Research using Drone

2022 IEEE 46th Annual Computers, Software, and Applications Conference (COMPSAC), Jun 1, 2022

Seismic Behavior of Partially Prestressed Concrete Piers

Doboku Gakkai Ronbunshu, Feb 20, 2001

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Evaluation of Weathering Steel Overhead Sign Structures in West Virginia

This report presents the results and findings of the research work aimed at evaluating 82 weather... more This report presents the results and findings of the research work aimed at evaluating 82 weathering steel sign structures in Charleston Interstate System in West Virginia. Twenty-six comprehensive inspection forms were developed to objectively evaluate the current condition of the following sign structure types: single and double arm ground mount cantilever structures; bridge superstructure mount cantilever structures; retaining wall mount cantilever structures; retaining wall mount truss structures; two-dimensional and three-dimensional ground mount truss structures; bridge parapet mount truss structures; and bridge frame mount structures. The work included performing extensive field inspection of the elements of each sign structure including the foundations, drainage issues, grout pads, base plates, anchor bolts/nuts/washers, connections between base plates and vertical columns, vertical columns and horizontal chords, connections between vertical columns and horizontal chords, welded splice connections, and attachments. An element condition rating was developed. The element condition rating took into consideration specific rating criteria ranging from severe to good condition. Current condition of each sign structure was then evaluated by an overall condition rating system. The overall condition rating is estimated based on calculating the ratio between the total score of each structure (S) and its maximum possible total score (Smax). Following the developed rating methodology presented in the report for the inspected weathering steel sign structures, seven percent were found to be at high risk, 50 percent were at moderate risk, and 43 percent were at low risk. The rating system is intended to assist the West Virginia Division of Highways (WVDOH) to make rational decisions on whether there is a need to repair or replace at-risk elements or connections. In-depth evaluations are recommended for the sign structures with the highest risk rating. Further evaluations are recommended for the sign structures with a moderate risk rating to detect any serious defects which may endanger the structure or the traveling public. Normal periodic inspections are recommended for the sign structures with a low risk rating.

Impact of environmental factors on condition assessment of concrete bridge decks using nondestructive testing

CRC Press eBooks, Aug 2, 2023

Detectability of embedded defects in FRP strengthened concrete deck slabs

CRC Press eBooks, Aug 2, 2023

Evaluating the Properties of Railway Ballast Using Spectral Analysis of Ground Penetrating Radar Signal Based on Optimized Variational Mode Decomposition

Advances in Civil Engineering, Oct 10, 2022

Ground penetrating radar (GPR) has been widely applied in the assessment of railway ballast condi... more Ground penetrating radar (GPR) has been widely applied in the assessment of railway ballast conditions (fouling, moisture) by using the spectrum of the tested GPR signal. However, the drawbacks of the low time-frequency resolution and mode mixing prevent the traditional spectrum methods from a wide application. This paper uses the advanced time-frequency analysis of GPR signal based on optimized variational mode decomposition to extract the features of ballast. The new approach overperforms the conventional frequency spectrum methods of GPR signal processing by giving a clear and quantitative assessment of ballast signals. Experimental results of GPR with dry and wet fouled ballasts demonstrate that, by comparison with the feature extraction method of conventional spectrum methods such as spectrogram and wavelet, the feature extraction method based on the optimized VMD has much better separability and quantitative identification capability.

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Deployment of Ground Penetrating Radar and Ultrasonic Tomographer Nondestructive Techniques for Assessment of Corrosion-Deteriorated Adjacent Pre-stressed Concrete Box Beams

Seismic assessment and evaluation of 520 highway bridges in Western Kentucky

Taylor & Francis eBooks, Jul 13, 2008

A Restoring Force Model for Partially Prestressed Concrete Piers

Transactions of the Japan Concrete Institute, Jun 1, 1999

Non-Destructive Testing and Evaluation of Timber and Steel H-Piles

Experimental Investigation of Post-Tensioned Anchored Trunnion Rods of Navigation Structures

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Assessment technologies of rail systems’ structural adequacy — A review from mechanical engineering perspectives

Science Progress, Apr 1, 2022

Seismic Risk Assessment of Priority Bridges along I-24 in Western Kentucky