Railway bridge geometry assessment supported by cutting-edge reality capture technologies and 3D as-designed models

Documentation of structural visual inspections is necessary for its monitoring, maintenance, and decision about its rehabilitation, and structural strengthening. In recent times, close-range photogrammetry (CRP) based on unmanned aerial vehicles (UAVs) and terrestrial laser scanners (TLS) have greatly improved the survey phase. These technologies can be used independently or in combination to provide a 3D as-is image-based model of the railway bridge. In this study, TLS captured the side and bottom sections of the deck, while the CRP-based UAV captured the side and top sections of the deck, and the track. The combination of post-processing techniques enabled the merging of TLS and CRP models, resulting in the creation of an accurate 3D representation of the complete railway bridge deck. Additionally, a 3D as-designed model was developed based on the design plans of the bridge. The as-designed model is compared to the as-is model through a 3D digital registration. The comparison allows the detection of dimensional deviation and surface alignments. The results reveal slight deviations in the structural dimension with a global average value of 9 mm.The authors would like to thank the financial support from: Base Funding—UIDB/04708/ 2020 and Programmatic Funding—UIDP/04708/2020 of the CONSTRUCT—“Instituto de I&D em Estruturas e Construções, as well as ISISE (UIDB/04029/2020) and ARISE (LA/P/0112/2020)”—funded by national funds through the FCT/MCTES (PIDDAC). Additionally, the support by the doctoral grant UI/BD/150970/2021 (to Rafael Cabral)—Portuguese Science Foundation, FCT/MCTES. Furthermore, this work is framed within the project “Intelligent structural condition assessment of existing steel railway bridges” financed by the bilateral agreement FCT-NAWA (2022-23), as well as project “FERROVIA 4.0”, with reference to POCI-01-0247-FEDER-046111, co-funded by the European Regional Development Fund (ERDF), through the Operational Program for Competitiveness and Internationalization (COMPETE 2020) and the Lisbon Regional Operational Program (LISBOA 2020), under the PORTUGAL 2020 Partnership Agreement, as well as “NEXUS: Innovation Pact Digital and Green Transition—Transports, Logistics and Mobility”, nr. C645112083-00000059, investment project nr. 53, financed by the Recovery and Resilience Plan (PRR) and by European Union—NextGeneration EU

Research Report and Findings: Specifications and Guidelines for Rail Tunnel Design, Construction, Maintenance, and Rehabilitation

Industry needs related to rail tunnel design, construction, maintenance, and rehabilitation were identified by reviewing past tunnel incidents and discussions with multiple transit agencies. Compilation of past tunnel incidents includes available reports published by the National Transportation Safety Board (NTSB) and other U.S. and European agencies. The tunnel structural design section covers geotechnical exploration/investigation, geometrical requirements and clearances, load and load combination, structural material and design considerations, waterproofing, and seismic design. Selection of tunnel type is based on geometrical configurations, ground conditions, type of crossing, and environmental requirements, and ground/structure interaction is important in the design process. Good knowledge of the expected geological conditions is essential. Tunnel structural components should satisfy many limit states: (1) service limit state as restriction on stress, deformation, and crack width under normal service conditions; (2) fatigue and fracture limit state as restriction on stress range; (3) strength limit state to ensure strength and stability; and (4) extreme event limit state to ensure the structural survival of a tunnel during a major earthquake, flood, tsunami, collision, blast, or fire. Special consideration is given to waterproofing systems and seismic design

Analytical and Measured Effects of Short and Heavy Rail Cars on Railway Bridges in the USA

The overall number of railcars recorded in the North American railcar fleet from 2010 to 2015 increased about 5%; the number of all 130 tonne (286,000 lb) gross weight railcars (heavy axle load (HAL) railcars) increased 19%. The increase in shipments in short railcars increases the loading on railway bridges, especially the 12.8-m railcars, commonly used to ship sand and cement, which is approximately a 25% increase in load per unit length compared to 16.2-m coal cars. Significant differences between maximum effects of shorter railcars and common 16.2-m railcars were predicted in analysis for bridge spans longer than 18.3 m. The differences were more prominent on spans 24.4 m and longer. This study presents analytical and measured effects of freight railcars on a two-span truss bridge, with spans of 61 m and 33.5 m, and a 35-m riveted steel deck plate girder (DPG) bridge. The investigation confirmed that short railcars cause higher load effects on main bridge components: the 35-m riveted steel DPG has 28% higher stresses at mid-span, while in the truss, the difference in stresses depends on the location of the member and ranges from 15 to 35%

Security and Safety of Rail Transit Tunnels

Transportation Technology Center, Inc., with support from the Center for Urban Transportation Research at the University of South Florida, was tasked by the FTA to research areas of transit safety risk, identify existing specifications and guidelines for rail transit tunnel design, construction, maintenance, and rehabilitation, and perform a gap analysis to establish the need for additional standards, guidance, or recommended practices to support and further the safe operation of the United States’ public transportation industry. This paper presents industry needs with a focus on security and safety that were identified by reviewing past tunnel incidents and related literature. The compilation of past tunnel incidents includes available reports published by the National Transportation Safety Board and other U.S. and European agencies. These reports generally involve rare but high-risk events such as fires and flooding, and emphasize public safety. A summary of needs obtained through a literature review emphasizes the need for continually updated specifications and best practices. The industry needs findings include the need for working fire detection, ventilation, and emergency egress along with coordinated emergency response plans that can be utilized by trained personnel

Research Report and Findings: Review of Specifications and Guidelines for Rail Tunnel Repair and Rehabilitation

After the Washington Metropolitan Area Transit Authority (WMATA) L\u2019Enfant Station rail accident in 2015, the National Transportation Safety Board (NTSB) issued two recommendations\u20141) Recommendation R-16-01: Issue regulatory standards for tunnel infrastructure inspection, maintenance, and repair, incorporating applicable industry consensus standards into those standards, and 2) Recommendation R-16-02: Issue regulatory safety standards for emergency egress in tunnel environments. To effectively respond to NTSB\u2019s recommendations, this report was prepared to assist the transit industry in developing standards and/or recommended practices to address Recommendation R-16-02 \u2013 tunnel repairs and rehabilitation and includes a condition-based rating system for tunnels as a tool for evaluation for rehabilitation and guidelines for a tunnel inventory database

Research Report and Findings: Specifications and Guidelines for Rail Tunnel Inspection and Maintenance

To effectively respond to recommendations of the National Transit Safety Board (NTSB), FTA contracted with researchers to assist the transit industry in developing standards and/or recommended practices for tunnel inspection and maintenance, repair/rehabilitation, and emergency egress. This report summarizes current industry maintenance and inspection practices based on data collected and compiled in 2017 and identifies and describes new technologies for groundwater intrusion remedies, inspection tools, and structural health monitoring. A literature review reveals inspection requirements, frequency, techniques, and documentation and tunnel condition rating criteria. The report presents findings based on standard comparisons, guideline assessments, and working group discussions

Advanced Railway Infrastructures Engineering

Electronic Instrumentatio