Highway Infrastructure Inspection Practices for the Digital Age (2022)

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5   C H A P T E R   1 Highway infrastructure such as roadways, bridges, and drainage systems is key for the livability, sustainability, and resilience of societies and communities. Inspection of highway infrastructure during construction and maintenance of assets is critical in any transportation system because it ensures conformance with plans, specifications, and material requirements, all of which can affect the life cycle of the asset. In fact, one of the main missions of state depart- ments of transportation (DOTs) and the FHWA is to provide high-quality products and facili- ties that meet or exceed specified quality standards. Traditionally, state DOTs have specified quality standards, including detailed instructions describing the required materials and con- struction methods, and have employed on-site workforces to perform infrastructure inspection during construction and maintenance of assets. The FHWA Every Day Counts (EDC) initiative promotes the use of various advanced and emerging technologies for construction and inspection. Under the e-construction innovation area of EDC-3 (2015–2016), FHWA focused on readily available and already-proven technolo- gies, including digital electronic signatures, electronic communications, secure file sharing, version control, mobile devices, web-hosted data archival and retrieval systems, and radio- frequency identification (RFID) tags for tracking the location of resources (FHWA 2017a). During EDC-4 (2017–2018), FHWA emphasized speeding up the adoption of e-construction and envisioned increasing the use of sophisticated technology applications across state agen- cies. These technology applications include having inspectors adopt survey-grade positioning data on tablets along with real-time data processing. FHWA used EDC-4 as an opportunity to promote e-ticketing, remote video monitoring, and seamless data integration across the project life cycle. For EDC-5 (2019–2020), FHWA focused on unmanned aircraft systems (UASs) to expedite data collection needed for making better-informed decisions while increasing safety and accuracy and providing access to hard-to-reach locations (FHWA 2019a). FHWA high- lighted that “construction inspection with UASs allows for a bird’s-eye view of a project’s prog- ress and for the development of 3D terrain models that document construction processes and assist in the assessment of earthwork quantity measurement” (FHWA 2019b). Recently, EDC-6 (2021–2022) was initiated. Under EDC-6, FHWA has focused on the use of technologies related to e-ticketing and digital as-builts. FHWA highlighted that “e-Ticketing improves the tracking, exchange, and archiving of materials tickets. Digital information, such as 3D design models and other metadata, enhances the future usability of as-built plans for operations, maintenance, and asset management” (FHWA 2021a). In the digital age, various technologies exist that can efficiently complete specific tasks and assignments. Emerging new and innovative technologies are changing how state DOTs deliver, inspect, and maintain their highway construction projects. In particular, with the incorporation of the latest technological advancements, the inspection landscape has been changing rapidly. The adoption of mobile devices and advanced surveying equipment for construction inspection Introduction

6 Highway Infrastructure Inspection Practices for the Digital Age has proved to be timely and beneficial for inspectors, who play a vital role in overseeing and managing construction processes and asset conditions. A wide variety of digital tools are avail- able to support construction inspection activities and collect digital data for estimation of quan- tities, verification and acceptance, and creation of as-built records. These tools offer numerous benefits, including improved data quality and consistency, enhanced communication, improved transparency, and improved safety for the site personnel. Geospatial technologies, remote sensing and monitoring technologies, mobile devices, 3D and 4D models, automated machine guidance (AMG), UASs, nondestructive evaluation methods, and other technologies are being used in the highway construction industry. The use and implementation of these technologies for construction inspection and maintenance of assets varies between state DOTs depending on their level of use and maturity. The variety of applications of and experiences with technologies is attributed to challenges and barriers that DOTs face in investigating, testing, and implementing specific technology tools for con- struction inspection and maintenance of assets. As technologies continue to be introduced and enhanced, state DOTs continue to consider and explore various technologies for highway infrastructure inspection. Therefore, the purpose of this synthesis is to document the various technologies used by DOTs to inspect highway infrastructure during construction and main- tenance of assets. Synthesis Scope, Goals, and Objectives This synthesis documents state DOTs’ applications and implementations of various tech- nologies in highway infrastructure inspection, focusing on four specific areas as shown in Table 1.1. The documentation of the uses of the technology aims to meet the synthesis objectives, which include: • Identifying technologies currently in use by DOTs for inspection of new and existing highway infrastructure assets (e.g., geospatial technologies, remote sensing and monitoring, mobile soft- ware applications, nondestructive evaluation); • Documenting primary methods used to assess the viability and efficiencies of inspection tech- nologies; and • Identifying how information from these assessments is being used for construction project management, allocating resources, and determining the condition of assets. Additionally, the synthesis documents lessons learned from individual DOTs through case examples regarding the implementation of technologies for highway infrastructure inspection. Finally, the synthesis identifies knowledge gaps and provides suggestions for future research to address these gaps. Synthesis Methodology To achieve the aforementioned objectives, the following approach was used for the develop- ment of the synthesis: • A literature review on the types and uses of inspection technologies, • A survey of state DOTs on their use of these technologies, and • Case examples of inspection technologies used by select DOTs. First, a comprehensive literature review was conducted that explored innovative and advanced technologies and their associated current practices in inspection of new and existing highway

Introduction 7   infrastructure assets. The literature review covered the following three areas: (1) technologies used for inspection of new and existing highway infrastructure assets; (2) available assessment methods for the viability, efficiencies, and return on investment (ROI) of inspection technologies; and (3) relevant information on the use of technologies for construction management, allocating resources, and determining highway asset conditions. On the basis of the information gathered from the literature review, and with input from the NCHRP panel, the research team developed a questionnaire and conducted a survey of state DOTs. The purpose of the survey was to gather information on current practices, uses, and implementation of technologies for construction inspection and asset management. The ques- tionnaire also allowed state DOT respondents to provide references to websites or documents on the investigated technologies. The survey questionnaire was distributed electronically to voting members of the AASHTO Committee on Construction, which includes DOT representatives from 50 states and the District of Columbia. Requests to participate in the survey resulted in 42 completed question- naires (an 82% response rate). The responses were then tabulated, analyzed, and supplemented with follow-up telephone calls and e-mails as needed for clarification. Technologies for Highway Infrastructure Inspection Examples Geospatial Technologies • Global Navigation Satellite Systems (GNSS)/ Global Positioning System (GPS) • Geographic Information Systems (GIS) • Robotic total stations (RTSs) • Terrestrial photogrammetry (TP) • Unmanned aircraft systems (UASs) (This technology is also considered to be part of remote sensing and monitoring) • E-ticketing (This technology is also considered to be part of software applications) Remote Sensing and Monitoring Technologies • Light imaging, Detection, and Ranging (LiDAR)/ 3D laser scanning • Radio-frequency identification (RFID) • Intelligent compaction (IC) • Remote sensors (e.g., accelerometers, maturity meter sensors, strain gauges) (RS) • Infrared sensors (e.g., thermal, motion detectors, object detection, thermal profiling) (IS) • Remote cameras (RC) • Barcodes and readers (BR) Mobile Devices and Software Applications • 3D engineered models/BIM (3D) • Automated machine guidance (AMG) • Tablet computers/smartphones (TS) • Handheld data collectors (e.g., Real-Time Kinematics (RTK), Trimble Yuma) (HDC) • Virtual reality (VR) • Augmented reality (AR) Nondestructive Evaluation Methods • Ground-penetrating radar (GPR) • Surface profile measuring systems • Dynamic test loading for piles • Ultrasonic testing • RTK GPS devices • Thermal integrity testing • Cross-hole sonic logging for drilled shafts • Falling weight deflectometers • Nuclear density gauges • Infrared thermography • Magnetic imaging tools (MITs) • Acoustic emission Note: BIM = building information modeling. Table 1.1. Technologies for highway infrastructure inspection.

8 Highway Infrastructure Inspection Practices for the Digital Age Finally, the case examples were conducted to supplement and validate the findings from the survey and obtain specific methods used to assess the viability, efficiencies, and ROI of inspection technologies, as well as determine how information obtained from these assessment methods is being used. The case examples were selected on the basis of the literature review and survey responses indicating an agency’s willingness to participate in the research. Eight case examples were conducted with the state DOTs of Florida, Illinois, Iowa, Minnesota, New York, Oregon, Pennsylvania, and South Dakota. These states actively use various technologies for construction inspection and maintenance of assets, and they indicated a willingness to participate further in the study. The case examples include documented information from DOT staff members and provide application examples for highway infrastructure inspection during construction and maintenance of assets. Synthesis Organization The remainder of this synthesis report contains four chapters covering the following topics: • Chapter 2: Literature review of technologies used for highway infrastructure inspection. • Chapter 3: Current practices of technology use by agencies for highway construction inspection and infrastructure assets, as collected through the state DOT survey. • Chapter 4: Case examples of eight state DOTs’ highway infrastructure inspection technolo- gies, covering technology implementation, use, benefits, challenges, and lessons learned. • Chapter 5: Key findings and future research to address knowledge gaps found by the synthesis.