Scour is the most common cause of catastrophic bridge failures worldwide. Approximately over 60% of bridge failures reported in the United States from 1966 to 2005 are scour related. To ensure the continued safe operation of bridges, monitoring bridge scour is of paramount importance. Most monitoring regimes that are widely used are based on expensive underwater instrumentation. This research focuses on scour detection using automated remote flow detection arrays based on bio-inspired flow sensors. This study employs an array of bio inspired flow sensors that are inexpensive and robust versions of buried-rod scour sensor arrays, coupled with low-power wireless sensor network utilizing civil-engineering domain wireless sensing units to detect scour around bridge piers and abutments. Sensors within the network that report dynamic flow signals are considered to be waterborne or located above the sediment and sensors reporting static signals are characterized as buried or as being located in sediment. The a priori information of sensor depth will help to establish the sediment level in real time. An automated data interrogation system collects data, processes the raw sensor data using in-network data interrogation methods, then and communicates the results to the on-site base station. The relative directness of this data interrogation adds to the robustness of the system. The main purpose of the scour detection system is to provide remote scour information to bridge owners in a format that is easy to comprehend as an aid in decision making. In this project, only processed results, not raw data, are transmitted to the user. The system under study utilizes a cellular data link to relay simplified data to the bridge owner to aid in decision making.
A robust program of validation has been conducted to define the limits of the approach in the laboratory in the field. This reports details research activities on whisker development for sensitivity and robustness, signal processing, hardware development, installation methods, automation, and visualization of results.
A copy of this report can be found on the National Transportation Library website.
Remote sensing technologies allow for the condition evaluation of bridge decks at near highway speed. Data collection at near highway speed for assessment of the top of the concrete deck and proof of concept testing for the underside of the deck was conducted for surface and subsurface evaluation. 3-D photogrammetry was combined with passive thermography to detect spalls, cracks and delaminations for the top of the concrete bridge deck, while active thermography was investigated for bottom deck surface condition assessment. Successful field demonstrations validated results comparable to MDOT inspections. Recommendations for immediate implementation for condition assessment of the top of a concrete deck are included for introducing the BridgeViewer Remote Camera System into current bridge inspections to provide a photo inventory of the bridge deck captured at 45mph and above using GoPro cameras. The combined optical photogrammetry (3DOBS) and passive thermography technologies provide an objective analysis of spalls, cracks and suspected delaminations while traveling at near highways speed. Using the same 3DOBS technology with higher resolution cameras and slower speeds, cracks can be detected as small as 1/32 in. Laboratory and field demonstrations show active thermography would benefit from further development as a remote sensing technology for condition assessment on the underside of the bridge deck.
A copy of this report can be found on the Michigan Department of Transportation website.
The Bridge Design System (BDS) is an in-house software program developed by the Michigan Department of Transportation’s (MDOT) Bridge Design Unit. The BDS designs bridges according to the required specifications, and outputs corresponding design drawings and calculations. It has been the primary design tool for MDOT’s bridges over the last several decades. Because of the BDS’s longevity of use and development, MDOT has experienced a high level of comfort, familiarity, and efficiency with it. However, components of the BDS have been added and removed over the years, and little associated documentation exists today. The code itself has seen nearly 60 years of evolution in the Fortran programming language. Migration to another software system is likely to require significant changes to MDOT business processes and may require multiple software systems rather than the unified design system of the BDS. Also, long-term viability of the BDS would require documentation of the existing architecture and operation of the system as well as development of a plan for future compatibility and functionality of the software. Therefore, the Center for Technology & Training at Michigan Tech was contracted to document, analyze and propose modernization options for the BDS. This report describes the tools used to conduct this assessment and the results of this task.
Closed-end, round, cast-in-place (CIP) tubular friction piles are commonly used in bridge and retaining wall structures in the State of Wisconsin. Installation of CIP piles is typically performed by the contractor according to specified bearing capacities in the construction plans. These CIP piles have historically been installed at depths ranging from 30 ft. to 120 ft., with nominal diameters between 10-3/4 in. and 14 in. and shell thicknesses between 1/4 in. and 3/8 in.
In this study, a series of field-cast piles are investigated both experimentally and numerically to assess their structural capacity. The evaluation consisted of testing stub sections of pile with varying diameters (10-3/4 in., 12-3/4 in.), wall thicknesses (0.375 in., 0.5 in.) under various states of stress. The focus was on the axial capacity, the bond capacity and the compressive strength of the core material.
A copy of this report can be found on the Wisconsin Department of Transportation website.
The Colorado Department of Transportation (CDOT) has identified potential performance problems in some portland cement concrete (PCC) bridge decks and approach slabs in the form of pattern surface cracking, spalling, and joint/crack deterioration, which are suspected to be materials-related distress (MRD). External factors, such as the use of deicing/anti-icing chemials, have the potential to initiate and increase the reate and magnitude of deterioration due to MRD, thereby shortening the life of the structure.
This paper details the results of a study conducted to investigate whether the application of highly concentrated deicer solutions through fixed automated spray technology (FAST) automated bridge deck deicing/anti-icing systems is disproportionately contributing to the deterioration of PCC bridge decks and adjacent concrete approach slabs in Colorado and whether the mitigation strategies being employed by CDOT are addressing the problem. The approach to this investigation involved the use of visual inspection techniques, materials sampling, and the evaluation of the sampled concrete using petrographic methods.
In the bridges studied, the concrete evaluated appears to be sufficiently resistant to damage from the intrusion of deicer chemicals, though where full-depth cracking was present, obvious signs of movement of moisture and deicers through the deck were observed in addition, some initial signs of possible chemical deicer attack were noted, and continued exposure to highly concentrated deicers may contribute to long-term durability concerns. However, the use of polymer-modified asphalt/fabric membranes in conjunction with a hot mix asphalt (HMA) overlay appears to be very effective in preventing the ingress of chlorides into the underlying concrete deck.
Initially researched as Phase I – Joint Deterioration Study.
Premature deterioration of concrete at the joints in concrete pavements and parking lots has been reported across the northern states. The distress is first observed as shadowing when microcracking near the joints traps water, later exhibiting as significant loss of material. Not all roadways are distressed, but the problem is common enough to warrant attention.
The aim of the work being conducted under this and parallel contracts was to improve understanding of the mechanisms behind premature joint deterioration and, based on this understanding, develop training materials and guidance documents to help practitioners reduce the risk of further distress and provide guidelines for repair techniques.
While work is still needed to understand all of the details of the mechanisms behind premature deterioration and prevention of further distress, the work in this report has contributed to advancing the state of knowledge.
A copy of the final report can be found at the National Concrete Pavement Technology Center website.
The Center for Structural Durability (CSD) explores research in the area of durable structural highway systems including ultra-high performance concrete applications, rapid construction for prestressed concrete bridges, and inspection and repair of transportation systems and bridges using remote sensing and other non-destructive inspection techniques. Structural durability related research helps state DOTs, federal agencies and industry clients achieve their performance goals of safety, mobility, and productivity of the transportation system while developing long-term solutions to improve the resiliency of our nation’s transportation structures.
SPONSOR: MICHIGAN DEPARTMENT OF TRANSPORTATION (MDOT)
PI: Tim Colling
This project provides Michigan local agencies and the consultants that serve them with the support and training necessary to ensure that they can be successful in meeting the new bridge load rating and requirements. Through this program, MDOT plans to maximize the chance of success for local agencies meeting the load rating requirements by providing support in three areas; training, software technical support and engineering technical assistance.
The desired result of the work plan is successful completion of load rating for Tier 1, 2 and 3 local agency owned bridges within their designated time limits as agreed upon by MDOT and FHWA.
The work plan consists of six major tasks:
Bridge load rating training development and delivery
Software technical support
Engineering technical assistance
Internal staff training
Project management, reporting and project meetings
Sponsor: US Department of Transportation Research and Innovative Technology Administration (RITA)
PI: Tess Ahlborn
The condition of the nation’s infrastructure has gained increased attention in recent years, primarily as a result of catastrophic events such as the I-35W collapse in Minneapolis. However, deteriorating transportation infrastructure has burdened transportation agencies for many years. Bridges continue to age, and funds for the repair and replacement of this infrastructure are insufficient at current funding levels. Remote sensing technologies, which enables non-contact data collection at great distances, offer the ability to enhance inspection and monitoring of bridges. Research Objectives The objective is to explore the use of remote sensing technologies to assess and monitor the condition of bridge infrastructure and improve the efficiency of inspection, repair, and rehabilitation efforts to develop unique signatures of bridge condition. Methodology Remote sensing technologies will be correlated with in-place sensors to obtain bridge condition assessment data without the need to place heavy instrumentation on the structure. This information will then be analyzed by a computer decision support system to develop unique signatures of bridge condition. Monitoring how these signatures change over time will provide state and local engineers with additional information used to prioritize critical maintenance and repair of our nation’s bridges. The ability to acquire this information remotely from many bridges without the expense of a dense sensor network will provide more accurate and near real-time assessments of bridge condition. Improved assessments allow for limited resources to be better allocated in repair and maintenance efforts, thereby extending the service life and safety of bridge assets, and minimizing costs of service-life extension.
Through Phase I of MDOT’s “Evaluating the Use of Unmanned Aerial Vehicles for Transportation Purposes” project, the Michigan Tech combined project team was successfully able to plan, demonstrate, and document UAV capabilities in the assessment of transportation assets.
With the rapid development of UAV’s, MDOT has requested additional research concerning their use for transportation asset management. The work plan of the MTU combined team includes:
Collect data from the UAV platform using sensing technology in near-time (as real-time as can be achieved) demonstrating, developing, and implementing storage capabilities of large amounts of data, usage of data, and application development that complements current data usage and application at MDOT.
Provide data collection from UAVs to the MDOT Data, Use, Analysis, and Process (DUAP) project that meets the quality, low latency delivery and data format requirements.
Provide a report that describes and recommends optional methods to store and distribute potentially large imaging, point cloud, and 3D surface datasets created through UAV-based data collection.
Demonstrate, develop, and implement high-accuracy simultaneous thermal/photo/video/Light Detection and Ranging (LIDAR) measurement using a high-fidelity sensor-fused UAV positioning approach.
Demonstrate the capabilities to complete aerial remote sensing data collections to meet MDOT mapping and construction monitoring needs. Coordinate with MDOT Survey Support to identify pilot projects and meet data delivery needs satisfying MDOT requirements for spatial data collection as it pertains to data density, absolute and relative 3D positional accuracy.
Demonstrate, develop and implement uses of data collection from UAV(s) and sensors for operations, maintenance, design, and asset management.
Demonstrate, develop and implement enhanced testing of UAV-based thermal imaging for bridge deck structural integrity.
Compare data collected from UAV sensors to current data collected and systems used at MDOT for highway assets/operations.
Demonstrate, develop, and implement systems management and operations uses.
Provide a benefit/cost analysis and performance measures that define the return on investment as a result of deploying UAVs and related sensory technologies for transportation purposes.
Secure a Federal Aviation Administration (FAA) Certificate of Authorization (COA) to complete the tasks and deliverables.