Utilizing Unmanned Aircraft Systems (UAS) for Bridge Inspections
Barritt Lovelace, Collins Engineers, Inc.Show Abstract
Jennifer Wells, Minnesota Department of Transportation
Tara Kalar, Minnesota Department of Transportation
The Minnesota Department of Transportation and Collins Engineers have been researching the use of Unmanned Aircraft Systems (UAS) as a tool for bridge inspections. Phase I of an implementation study has been completed, and a Phase II study is nearing completion. These research studies are looking at current FAA regulations and are evaluating the advantages and challenges of using UAS for bridge inspections with promising results. Our research studies tested different types of UAS on seven different bridges of varying types, sizes, locations and conditions to determine their effectiveness as a tool to supplement bridges inspections.
Bridge Geometry Measurements with an Unmanned Aerial Vehicle Flown in Local Wind Disturbances
Abraham Lama Salomon, gNext Labs LLCShow Abstract
Benjamin Straub, Virginia Polytechnic Institute and State University
Andrew Kriz, Virginia Polytechnic Institute and State University
Daniel Stilwell, Virginia Polytechnic Institute and State University
Matthew Hebdon, Virginia Polytechnic Institute and State University
This work describes an experiment to document local wind disturbances created in the proximity to the US52 Wolf Creek Bridge, asses the effect of these disturbances on Unmanned Aerial Vehicle (UAV) flight and sensing performance, and evaluate bridge geometry measurements from a video recorded during the flight test. The visual data was used to create permanent 3D records or digital state models (dSMs) of the structure which were validated with measurements from features such as beam flange thicknesses, bearing plate thicknesses and drain pipe widths using a digital caliper. Based on the results of this test and with proper planning and execution, UAVs equipped with an onboard camera can be used to reliably measure features in bridge structures with an accuracy of ± 0.10 in. (2.54 mm). In addition, the use of higher resolution video cameras is expected to improve accuracy even further. It was found that for this specific location, little correlation could be made between the nominal wind speed and the localized wind speeds measurements. The localized wind speeds measured ranged from 60% to 800% of the nominal wind speed at any given time .Further work is needed to improve autopilot control, sensor readings, and to better understand local wind disturbances in close proximity of bridges with accompanying control methods.
Methodology for Ranking Relative Importance of Structures to Virginia’s Roadway Network
Audrey Moruza, Virginia Transportation Research CouncilShow Abstract
Adam Matteo, Virginia Department of Transportation
In 2011, the Structure and Bridge Division of the Virginia Department of Transportation (VDOT) requested assistance from the Virginia Transportation Research Council to develop a structure scoring tool that would rank the relative importance of VDOT-maintained structures to the highway network and to the economy of Virginia. No scoring tool existed in 2011 that systematically incorporated non–condition-based structure features known to be relevant to decision-makers, such as intensity of travel demand for a structure relative to its capacity, the relative magnitude of user costs imposed by potential closure of the structure, and the relative impact of closure of a particular structure on key nearby facilities.
The new tool produces a structure score dubbed the “Importance Factor” (IF ) for all open structures in VDOT’s current inventory database. IF scores are based on current data in the structure inventory database, supplemented by geopositional data that identify schools, hospitals, and fire/rescue stations within 3 miles of each eligible structure. The IF score adds the critically important dimension of the structure’s role in the highway system and the economy of Virginia to other structure scoring tools that measure condition and age factors. IF scores are relative rankings of eligible VDOT-maintained structures with no stand-alone value. They may be updated each time a structure inventory database is refreshed.
The staff of VDOT’s Structure and Bridge Division has incorporated this methodology as part of a multi-objective prioritization formula for Virginia structures in response to MAP-21 requirements regarding “State of Good Repair.” The new formula incorporates independent, normalized, dimensionless variables that address functionality, risk, importance, condition (health index), and cost-effectiveness. This methodology fulfills the importance component.
A Procedure for Load Rating Reinforced Concrete Slab Bridges without Plans
Alain Cuaron, New Mexico State UniversityShow Abstract
David Jauregui, New Mexico State University
Brad Weldon, New Mexico State University
In New Mexico, bridges without plans are currently an issue as in other states in the U.S. Standard techniques cannot be used for load rating due to the lack of design plans that contain necessary information such as material properties and the amount and location of the steel reinforcement. In this study, the state departments of transportation were surveyed regarding their load rating policies and procedures for planless bridges. Many states reported a significant amount of bridges without plans in particular reinforced concrete bridges and the rating approaches vary from state to state. This project was conducted for the New Mexico Department of Transportation (NMDOT) to develop an effective method to load rate reinforced concrete slab bridges without plans and obtain more representative estimates of load-carrying capacity. Twenty-three reinforced concrete slab bridges (simple and continuous span) were load rated and evaluated using simple analytical and non-destructive testing techniques. The procedure includes field measurement of the bridge dimensions and geometry, Windsor Probe testing of the concrete strength, scanning of the hidden steel reinforcement, generation of as-built drawings, and modeling the bridge with a load rating software. The procedure provided the NMDOT with as-built plans as well as more realistic load rating results reinforced concrete slab bridges without design plans. Comparisons are made with other state policies to illustrate the differences in the load ratings.