Showing papers in "Journal of Bridge Engineering in 2019"
TL;DR: This paper proposes a process using an imagery-based point cloud to provide safer, more economical, and less disruptive bridge inspection, including data acquisition, 3D reconstruction, quality evaluation, and subsequent damage detection.
Abstract: 10 Imagery-based, three-dimensional (3D) reconstruction from Unmanned Aerial Vehicles (UAVs) 11 holds the potential to provide safer, more economical, and less disruptive bridge inspection. In 12 support of those efforts, this paper proposes a process using an imagery-based point cloud. First, 13 a bridge inspection procedure is introduced, including data acquisition, 3D reconstruction, data 14 quality evaluation, and subsequent damage detection. Next, evaluation mechanisms are proposed 15 including checking data coverage, analysing points distribution, assessing outlier noise, and 16 measuring geometric accuracy. In this final aspect, the “Guide to the Expression of Uncertainty 17 in Measurement” was used. The overall approach is illustrated in the form of a case study with a 18 low-cost UAV. Areas of particular coverage difficulty involved slim features such as railings, 19 where obtaining sufficient features for image matching proved challenging. Shadowing and large 20 tilt angles hid or weakened texturing surfaces, which also interfered with the matching process. 21 22 23
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TL;DR: In this paper, the authors investigated the influence of several variables, such as normal concrete strength, interface roughness, and curing condition on the shear transfer behavior across the interface between UHPC and NC.
Abstract: Ultrahigh performance concrete (UHPC) is an advanced cementitious material which has excellent mechanical and durability properties, making it appropriate for the rehabilitation of concrete structures. This paper investigates the usage of a thin layer of UHPC overlaying a normal strength concrete (NC) deck. The behavior of the interface connection will have a significant impact on the overall structural and durability performance of the UHPC-NC composite deck system. An integrated experimental and analytical study was conducted to understand the influence of several variables, such as normal concrete strength, interface roughness, and curing condition on the shear transfer behavior across the interface between UHPC and NC. The laboratory testing was performed in two phases, including slant shear testing in Phase-I and flexural testing of composite deck specimens in Phase-II. A total of sixty test units with five different surface textures and three different concrete strengths were loaded to failure in Phase-I. Four 197 mm (7.75 in.) thick, 0.61 m (2 ft) wide, and 2.74 m (9 ft) long deck specimens with 38 mm (1.5 in.) thick UHPC overlay and different interface texture were tested to failure in Phase-II. The slant shear test results demonstrated that the shear transfer across the interface is adequate for overlay applications for all textures with roughness equal or more than 3 mm (0.12 in.) regardless of concrete strength, which was later confirmed by the composite deck specimen tests. The interface bond strength was not affected by curing conditions (heat treatment or ambient) used for UHPC. Current bridge design guidelines provide a conservative estimate for the UHPC-NC interface shear strength.
56 citations
TL;DR: In this article, the authors provided a comprehensive review of experimental studies on corrosion damaged reinforced concrete (RC) components, and the ability of current state-of-the-art numerical models to predict the residual capacity of these corroded RC components.
Abstract: The current paper provides a comprehensive review of experimental studies on corrosion damaged reinforced concrete (RC) components, and the ability of current state-of-the-art numerical models to predict the residual capacity of these corroded RC components. The experimental studies on corroded RC components are classified into five different categories including: (i) beams in flexure, (ii) beams in shear, (iii) columns under pure axial compression, (iv) circular columns in flexure, and (v) rectangular columns in flexure. For each group, a summary of all the previous research are provided. Through the regression analyses, the experimental results of each abovementioned groups are used to examine the adverse effect of corrosion on ductility and, flexural, shear, and axial capacity loss of the corroded RC components. Finally, the observed results of the previous experimental studies are compared with the predicted values using the state-of-the-art numerical models currently available in the literature. The summarised experimental results show that corrosion has much more adverse impact on ductility of the RC columns than strength. However, the effect of corrosion on ductility and strength reduction of RC beams is the same. Moreover, results of cross-sectional moment-curvature analyses using the state-of-the-art corrosion damage models show a good correlation between the predicted residual flexural capacity and observed experimental results. Finally, the existing shortcomings in the literature and open issues to be addressed in the future research are discussed, and some recommendations are provided.
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TL;DR: In this article, the authors present a behavior analysis and early warning of girder deflection in railway bridges, using temperature fields and crossing high-speed trains to monitor deflection of railway bridges.
Abstract: Complicated temperature fields and crossing high-speed trains offer new challenges for monitoring girder deflections in operating railway bridges. Behavior analyses and early warning of gir...
46 citations
44 citations
TL;DR: The National Bridge Inventory reports indicate that a noticeable portion of the United States bridge infrastructure is drastically approaching the end of its intended design life, mainly due to bridge failures as mentioned in this paper. But, as
Abstract: The National Bridge Inventory reports indicate that a noticeable portion of the United States bridge infrastructure is drastically approaching the end of its intended design life, mainly du...
TL;DR: This is the author accepted manuscript and the final version is available from American Society of Civil Engineers via the DOI in this record.
Abstract: This is the author accepted manuscript. The final version is available from American Society of Civil Engineers via the DOI in this record.
TL;DR: In this article, a quantitative framework was developed to assess life-cycle resilience of deteriorating reinforced concrete (RC) bridges under seismic ground motions (GMs), and a three-span RC bridge under GMs was evaluated.
Abstract: A quantitative framework was developed to assess life-cycle resilience of deteriorating reinforced concrete (RC) bridges under seismic ground motions (GMs). Deterioration of a three-span RC...
TL;DR: In this article, the authors used a number of graduate students for their help during the experimental program, which was supported by the University of Arkansas at Fayetteville, Ton Duc Thang University, and Southern Plains Transportation Center.
Abstract: This research is supported by the University of Arkansas at Fayetteville, Ton Duc Thang University, and Southern Plains Transportation Center. The authors are thankful to a number of graduate students for their help during the experimental program.
TL;DR: In this paper, large wave forces induced by the combination of storm surge and hurricane waves have caused significant damage and failure of various coastal bridges in the Gulf of Mexico, and existing researc...
Abstract: Large wave forces induced by the combination of storm surge and hurricane waves have caused significant damage and failure of various coastal bridges in the Gulf of Mexico. Existing researc...
TL;DR: In this article, the temperature gradients of concrete-filled steel tubes (CFSTs) have been applied widely as the main members in bridge structures; however, the temperature gradient has not been studied sufficiently.
Abstract: Concrete-filled steel tubes (CFSTs) have been applied widely as the main members in bridge structures; however, the temperature gradients have not been studied sufficiently. To fill this ga...
TL;DR: This data indicates that regular bridge inspections are key to maintaining healthy infrastructure and to preventing unanticipated structural failures and mobile inspection robots proposed as solutions to these problems are likely to be underestimated.
Abstract: Regular bridge inspections are key to maintaining healthy infrastructure and to preventing unanticipated structural failures. In recent years, mobile inspection robots have been proposed as...
TL;DR: In this article, a beam-on-nonlinear-Winkler-foundation model with or without the consideration of bond-slip effect at pile head/cap connections is built in accordance with quasi-static testing of a 2 3 RC pile-cap foundation, and validated in various aspects, including the global forcedisplacement relationship, the failure mechanism, and the location of plastic hinges.
Abstract: For bridges under seismic excitations, current design practices recommend to comply with the capacity protection principle for pile foundations. However, in cases, such as elevated (or scoured) RC pile-cap foundation typologies that are partially embedded, the piles may suffer large deflections under lateral loads, which make it difficult for them to remain in the elastic state. In this regard, the present study makes an in-depth analysis on the ductile behavior of elevated RC pile-cap foundations to explore potentials for seismic ductile design. A beam-on-nonlinear-Winkler-foundation model with or without the consideration of bond-slip effect at pile head/cap connections is built in accordance with quasi-static testing of a 2 3 elevated RC pile-cap foundation, and validated in various aspects, including the global forcedisplacement relationship, the failure mechanism, and the location of plastic hinges. The validation results indicate that the bond-slip effect is generally unremarkable and can be neglected for the modeling of studied elevated pile-cap foundations (EPFs). Two limit states and the corresponding ductility factors, named easy-to-repair and ultimate displacement ductility factors, are proposed for EPFs. Parametric pushover analyses are then performed to investigate the impact of structural and geotechnical parameters on the ductile behavior of real-scale 2 3 elevated RC pile-cap foundations embedded in homogeneous and multilayered cohesionless soils. The numerical results show considerable ductile capacities (with an average quantified as 2.77 and 4.05 for the easy-to-repair and ultimate displacement ductility factors, respectively) for elevated RC pile-cap foundations. Additionally, a mathematical relationship between displacement and curvature ductility factors is established for future ductility-based design practices.DOI: 10.1061/(ASCE)BE.1943-5592.0001328.© 2018 American Society of Civil Engineers. Author keywords: Elevated RC pile-cap foundation; Parametric analysis; Pushover; Ductility; Scour; FEM.