Adaptive Wavelet Neural Network For Terrestrial Laser Scanner-Based Crack Detection, 2018 Oregon State University
Adaptive Wavelet Neural Network For Terrestrial Laser Scanner-Based Crack Detection, Yelda Turkan, Jonathan Hong, Simon Laflamme, Nisha Puri
Civil, Construction and Environmental Engineering Publications
Objective, accurate, and fast assessment of civil infrastructure conditions is critical to timely assess safety risks. Current practices rely on visual observations and manual interpretation of reports and sketches prepared by inspectors in the field, which are labor intensive, subject to personal judgment and experience, and prone to error. Terrestrial laser scanners (TLS) are promising for automatically identifying structural condition indicators, as they are capable of providing coverage for large areas with accuracy at long ranges. Major challenges in using this technology are in storing significant amount of data and extracting appropriate features enabling condition assessment. This paper proposes a ...
Vertical Shear Wave Velocity Profiles Generated From Spectral Analysis Of Surface Waves: Field Examples, 2018 Missouri University of Science and Technology
Vertical Shear Wave Velocity Profiles Generated From Spectral Analysis Of Surface Waves: Field Examples, Neil Lennart Anderson, Genda Chen, Siasi Kociu, Ronaldo Luna, Thanop Thitimakorn, Alexi A. Malovichko, D. Malovichko, D. Shylakov
Surface wave (Rayleigh wave) seismic data were acquired at six separate bridge sites in southeast Missouri. Each acquired surface wave data set was processed (spectral analysis of surface waves; SASW) and transformed into a site-specific vertical shear-wave velocity profile (SASW shear-wave velocity profile). The SASW shear-wave velocity profiles generated for each bridge site were compared to other geotechnical data including seismic cone penetrometer shear-wave velocity profiles, cross-borehole shear-wave velocity profiles, and borehole lithology logs. The geotechnical data presented herein indicate the SASW shear-wave velocity profiles correlate well with subsurface lithology logs and available cross-borehole shear-wave velocity control. More specifically, clays ...
Unbonded Portland Cement Concrete Overlay/Pavement Monitoring With Integrated Grating And Scattering Optical Fiber Sensors, 2018 Missouri University of Science and Technology
Unbonded Portland Cement Concrete Overlay/Pavement Monitoring With Integrated Grating And Scattering Optical Fiber Sensors, Genda Chen, Ying Huang, Yi Bao
This report summarizes the findings and results from a laboratory and field study on the strain distribution and crack development in 3" thick concrete panels cast on top of existing concrete pavements as a rapid rehabilitation strategy for roadways. Both fiber Bragg gratings (FBG) and Brillouin Optical Time Domain Reflectometry/Analysis (BOTDR/A) were applied and tested for their feasibility and effectiveness in distributed strain measurement and crack detection. For laboratory tests, six 6'×6" panels were cast similar to their corresponding field construction. Each was tested under both truck loads and under threepoint loads. The performance of distributed BOTDR ...
Temperature And Strain Measurements With Fiber Optic Sensors For Steel Beams Subjected To Fire, 2018 Missouri University of Science and Technology
Temperature And Strain Measurements With Fiber Optic Sensors For Steel Beams Subjected To Fire, Yi Bao, Yizheng Chen, Matthew S. Hoehler, Christopher M. Smith, Matthew F. Bundy, Genda Chen
This paper presents measurements of high temperatures using a Brillouin scattering based fiber optic sensor and large strains using an extrinsic Fabry-Perot interferometric sensor for assessing the thermo-mechanical behaviors of simply supported steel beams subjected to combined thermal and mechanical loading. The distributed fiber optic sensor captures detailed, non- uniform temperature distributions that are compared with thermocouple measurements resulting in an average relative difference of less than 5 % at 95 % confidence level. The extrinsic Fabry- Perot interferometric sensor captures large strains at temperatures above 1000 C. The strain results measured from the distributed fiber optic sensors and extrinsic Fabry-Perot interferometric ...
Structural Assessment Of Highway "N" Power Substation Under Earthquake Loads, 2018 Missouri University of Science and Technology
Structural Assessment Of Highway "N" Power Substation Under Earthquake Loads, Genda Chen, Dongming Yan, Zuocai Wang, Seth Justin, J. David Rogers, Kazi Rezaul Karim
In this study, the Highway N Substation was analyzed with a finite element model (FEM) for its vulnerability. The 'rigid' bus and electric switch components were characterized with full scale shake table tests. Each component of the substation was carefully modeled with due considerations of mass density, stiffness and geometries. Based on the FEM, modal analysis was conducted to identify the natural frequencies of the structure along with their corresponding mass participation factors. In response spectrum and time history analyses, the dynamic responses of main components, such as 'rigid' buses and switches, were evaluated. The magnitude and location of the ...
Strengthening Of Rural Bridges Using Rapid-Installation Frp Technology: Route 63 Bridge No. H356, Phelps County, 2018 Missouri University of Science and Technology
Strengthening Of Rural Bridges Using Rapid-Installation Frp Technology: Route 63 Bridge No. H356, Phelps County, Dongming Yan, Jianbo Li, Chenglin Bob Wu, Genda Chen
This report presents the use of externally bonded fiber reinforced polymers (FRP) laminates for the flexural strengthening of a concrete bridge. The bridge selected for this project is a two-span simply supported reinforced concrete slab with no transverse steel reinforcement located in Phelps County, MO. The original construction combined with the presence of very rigid parapets caused the formation of a 1-inch wide longitudinal crack, which resulted in the slab to behave as two separate elements. The structural behavior was verified using a finite element model (FEM) of the bridge. The bridge analysis was performed for maximum loads determined in ...
Strain Distribution And Crack Detection In Concrete Overlays With Pulse Pre-Pump Brillouin Optical Time Domain Analysis, 2018 Missouri University of Science and Technology
Strain Distribution And Crack Detection In Concrete Overlays With Pulse Pre-Pump Brillouin Optical Time Domain Analysis, Yi Bao, Genda Chen
This report is focused on the measurement of strain distributions and crack detection in unbonded and bonded pavement overlays. The main objectives of this study are: (a) to characterize the strain sensing properties of distributed fiber optic sensors with recently developed pulse pre-pump Brillouin optical time domain analysis (PPP-BOTDA), (b) to develop an installation method for real world applications, (c) to document the performance of the PPP-BOTDA technology in unbonded/bonded pavement applications, and (d) to develop a numerical model to facilitate the analysis of mechanical behavior of unbonded pavement overlay under vehicle wheel loads. A thin concrete layer can ...
Steel Building Assessment In Post-Earthquake Fire Environments With Fiber Optical Sensors, 2018 Missouri University of Science and Technology
Steel Building Assessment In Post-Earthquake Fire Environments With Fiber Optical Sensors, Genda Chen, Ying Huang, Hai Xiao
No abstract provided.
Signal Mast Arm Fatigue Failure Investigation, 2018 Missouri University of Science and Technology
Signal Mast Arm Fatigue Failure Investigation, Genda Chen, Michael G. Barker, Lokeswarappa R. Dharani, Christopher W. Ramsay
The Missouri Department of Transportation (MoDOT) has discovered and documented failures in several cantilever mast arms in the recent years. The failures were primarily by fatigue at the weld of the arm to the base plate attached to the mast. With over 6000 mast arms in service in Missouri, the failures raised concerns with the existing mast arm inventory and future mast arm design. This report presents findings from an effort to determine the cause of unexpected cracking in Missouri mast arms. Three causes of premature failure were investigated: the stress ranges experienced at the weld detail were higher than ...
Smart Rocks And Wireless Communication System For Real-Time Monitoring And Mitigation Of Bridge Scour -- A Proof-Of-Concept Study, 2018 Missouri University of Science and Technology
Smart Rocks And Wireless Communication System For Real-Time Monitoring And Mitigation Of Bridge Scour -- A Proof-Of-Concept Study, Genda Chen, David Pommerenke, Y. Rosa Zheng, Andriy V. Radchenko, Yan Tang, Brandon P. Schafer, Ying Huang, Z. L. Yang
This study aims to integrate commercial measurement and communication components into a scour monitoring system with magnets or electronics embedded in smart rocks, and evaluate and improve its performance in laboratory and field conditions for the movement of smart rocks. Properly-designed smart rocks were found to be automatically rolled into the very bottom of a scour hole and can give critical information about the maximum scour depth and effectiveness of rip-rap mitigation strategies. Four types of smart rock technologies were investigated in this proof-of-concept phase of study, including passive with embedded magnets, active with magneto-inductive communication, active with controllable magnet ...
Seismic Retrofit Of Ciss Pile Bent Cap Connections, 2018 Missouri University of Science and Technology
Seismic Retrofit Of Ciss Pile Bent Cap Connections, Michael C. Lubiewski, Pedro Franco Silva, Genda Chen
Three 4/5-scale units were cast, retrofitted, and tested under simulated seismic loads. These units were built to model a bridge bent consisting of a cast in place steel shell (CISS) column foundation shaft and a bent cap configured to form a tee connection. Each unit was retrofitted in the column, bent cap, and their connection according to current seismic design standards. The main objective was to ensuring ductile performance under lateral loads.
Specific seismic improvements made to the column and the bent cap system were: (1) the moment capacity of the column was reduced by cutting a portion of ...
Post-Earthquake Reconnaissance Report On Transportation Infrastructure Impact Of The February 27, 2010, Offshore Maule Earthquake In Chile, 2018 Missouri University of Science and Technology
Post-Earthquake Reconnaissance Report On Transportation Infrastructure Impact Of The February 27, 2010, Offshore Maule Earthquake In Chile, Wen-Huei Phillip Yen, Genda Chen, Ian G. Buckle, Tony M. Allen, Daniel E. Alzamora, Jeffrey Ger, Juan G. Arias
This report documents the findings and lessons learned from the February 27, 2010, M8.8 offshore Maule earthquake in Chile. Fewer than 0.15 percent of the bridges in Chile's inventory, most built after 1995, collapsed or suffered damage that rendered them useless. Many spans of precast prestressed discontinuous girder bridges with continuous decks fell off their supports, probably due to significant in-plane rotation of the superstructure as a result of severe shaking. Lateral steel stoppers used to provide both vertical and lateral restraints on girders were largely unsuccessful due to their inadequate connection detail to cap beams and ...
Nondestructive Evaluation Of Mechanically Stabilized Earth Walls With Frequency-Modulated Continuous Wave (Fm-Cw) Radar, 2018 Missouri University of Science and Technology
Nondestructive Evaluation Of Mechanically Stabilized Earth Walls With Frequency-Modulated Continuous Wave (Fm-Cw) Radar, Mohammad Tayeb Ahmad Ghasr, Yi Bao, Kuang Ying, K. M. Combs, R. Zoughi, Genda Chen
Effective techniques for a nondestructive evaluation of mechanically stabilized earth (MSE) walls during normal operation or immediately after an earthquake event are yet to be developed. MSE walls often have a rough surface finishing for the purpose of decoration and are reinforced with both horizontal and vertical steel bars. Two wide-band microwave inspection approaches were investigated for detecting and evaluating characteristics of materials behind an MSE wall section. The first approach used spot measurements with a wide-band frequency-modulated continuous wave (FM-CW) radar system. While effective to penetrate through mortar blocks in the laboratory, the radar system was found to have ...
Investigation Of Cause Of Cracked Stringer On The Blanchette Bridge, 2018 Missouri University of Science and Technology
Investigation Of Cause Of Cracked Stringer On The Blanchette Bridge, Ward Marianos Jr., Genda Chen, Nestore Galati, Fabio Matta
The Blanchette Bridge carries Interstate 70 across the Missouri River, connecting St. Louis and St. Charles counties in eastern Missouri. The westbound bridge was constructed in 1958. In 1979, the original reinforced concrete roadway deck on the bridge was replaced with a steel grid deck system, welded to supporting girders and stringers. In 1999 and 2005, cracks were discovered in stringers on the bridge approach spans. The stringers were repaired with bolted splices.
The investigation of the cracking included preliminary analyses, review of historical documents, detailed finite element analyses, and field testing of the bridge. The cracking was determined to ...
Initial Study And Verification Of A Distributed Fiber Optic Corrosion Monitoring System For Transportation Structures, 2018 Missouri University of Science and Technology
Initial Study And Verification Of A Distributed Fiber Optic Corrosion Monitoring System For Transportation Structures, Hai Xiao, Genda Chen, Zhan Gao, Ying Huang, Fujian Tang
For this study, a novel optical fiber sensing system was developed and tested for the monitoring of corrosion in transportation systems. The optical fiber sensing system consists of a reference long period fiber gratings (LPFG) sensor for corrosive environmental monitoring and a LPFG sensor coated with a thin film of nano iron and silica particles for steel corrosion monitoring. The environmental effects (such as pH and temperature) are compensated by the use of the reference LPFG sensor. The sensor design, simulation, and experimental validation were performed in this study to investigate the feasibility of the proposed sensing system for corrosion ...
Failure Investigation Of The Steel Strut Of Paseo Suspension Bridge, 2018 Missouri University of Science and Technology
Failure Investigation Of The Steel Strut Of Paseo Suspension Bridge, Genda Chen, Chris Courtright, Lokeswarappa R. Dharani, B. Xu
A vertical strut of the 1232-foot long, self-anchored Paseo Suspension Bridge fractured when the temperature hit at a record low of 9°F below zero. During inspection the following day, it was found that its lower pin was frozen and did not allow for free movement of the superstructure. The objective of this study is to pinpoint one of the four reasons for this incidence or their combination: overstressing, thermal contraction, fatigue, and reduction in fracture toughness at low temperatures. To achieve this objective, material property and fatigue testing was performed on samples of strut material while the bridge and ...
Earthquake Hazard Assessment Along Designated Emergency Vehicle Priority Access Routes, 2018 Missouri University of Science and Technology
Earthquake Hazard Assessment Along Designated Emergency Vehicle Priority Access Routes, Neil Lennart Anderson, Hal Baker, Genda Chen, Tom Hertell, David J. Hoffman, Ronaldo Luna, Yulman Munaf, Shamsher Prakash, Paul Michael Santi, Richard Wesley Stephenson
Because of the compelling need to reopen vehicular access routes to Sikeston, Cape Girardeau and St. Louis following a devastating earthquake, Missouri Department of Transportation initiated a study of those portions of US 60 and MO 100 that have been officially designated as emergency vehicle priority access routes. The primary objectives of this study were twofold. Objective 1 was to establish a current subsurface and earthquake design geographic information systems (GIS) database for areas in proximity to designated portions of US 60 and MO 100 (includes counties of Butler, Stoddard, New Madrid, Franklin and St. Louis). Objective 2 was to ...
Destructive And Non-Destructive Testing Of Bridge J857 Phelps County, Missouri : Strengthening And Testing To Failure Of Bridge Piers, 2018 Missouri University of Science and Technology
Destructive And Non-Destructive Testing Of Bridge J857 Phelps County, Missouri : Strengthening And Testing To Failure Of Bridge Piers, Tarek Alkhrdaji, Antonio Nanni, Genda Chen
Many of the existing reinforced concrete (RC) bridge piers constructed in the first half of this century were designed as gravity piers with minimal flexural reinforcement and no consideration to seismically induced lateral forces. When considered in earlier designs, the seismic lateral forces were typically low. The potential risk of failure of columns on these piers under a moderate earthquake is becoming a growing concern for the transportation management agencies. In addition, flexural strength deficiency in RC columns may arise from the loss of reinforcement due to corrosion, premature termination of the main reinforcement, or inadequate splicing. One method for ...
Development Of Bridge Girder Movement Criteria For Accelerated Bridge Construction, 2018 Missouri University of Science and Technology
Development Of Bridge Girder Movement Criteria For Accelerated Bridge Construction, Genda Chen, Yi Bao
End diaphragms connect multiple girders to form a bridge superstructure system for effective resistance to earthquake loads. Concrete girder bridges that include end diaphragms consistently proved to perform well during previous earthquake events. However, whether concrete bridges without end diaphragms are definitively inadequate in seismic performance is yet to be answered. The 2010 Chile Earthquake indicated that properly designed bridge girders and their lateral movement stoppers (shear keys) may perform equally well with those with end diaphragms. In this report, a feasibility study on the design of girder bridges without end diaphragms is presented. This study is particularly significant in ...
Design, Construction And Load Testing Of The Bridge On Arnault Branch, Washington County, Missouri Using Innovative Technologies, 2018 Missouri University of Science and Technology
Design, Construction And Load Testing Of The Bridge On Arnault Branch, Washington County, Missouri Using Innovative Technologies, Dongming Yan, Genda Chen, Nestore Galati, Sahra Sedigh
The superstructure and instrumentation designs of a three-span bridge are presented in this report. The three spans include a precast box-girder bridge, a precast deck on steel girder and a precast deck on concrete girder. They were designed to compare the performance of various bridge decks reinforced with fiber reinforced polymers (FRP) through field instrumentations. A wireless monitoring system was designed to facilitate the collection of field data after the completion of bridge construction. The collected data will allow the study of FRP bars and stay-in-place FRP grid systems.