Projects

Modernizing Legacy Infrastructure with BIM and Laser Scanning: Bethesda Pedestrian Bridge Case Study

Public utility infrastructure ranges from transit corridors and parking structures to pedestrian networks and more. This infrastructure forms the lifeblood of urban development. These assets enable connectivity and more importantly, uphold safety, accessibility, and economic activity across communities. Regardless of the significance of these infrastructures, many of them, especially legacy installations, suffer from limited or outdated documentation. Due to this, activities like maintenance and retrofitting are becoming increasingly complex and risk-prone.  

With the rise of 3D laser scanning and Building Information Modeling services, public agencies now have the opportunity to transform aging infrastructure assets digitally.  Scan-to-BIM services offer a precise and non-invasive method to capture existing site conditions. The reality capture data collected can be used in creating digital twins, the digital replica of the scanned site. This technology can support efficient project planning and enable proactive and predictive facility management. 

In this case study, we explore how Tejjy Inc. was selected by the Montgomery County Department of Transportation (MCDOT) to execute a digital documentation strategy for the Pedestrian Bridges (OGTR and Edgemoor) in Bethesda. As an 8(a)-certified AEC company with a strong track record in digital construction practices for federal and public infrastructure projects, Tejjy Inc. was entrusted with the responsibility of bridging the gap between outdated documentation and modern infrastructure needs.  

The Challenge: Legacy Infrastructure, Limited Documentation 

The OGTR (Old Georgetown Road) and Edgemoor lane Pedestrian Bridge in Bethesda, Maryland, are more than a simple walkway, they are a vital public utility that supports safe pedestrian transit in one of the area’s busiest urban corridors. Like many components of legacy infrastructure, the bridge continued to serve the community effectively. But beneath its surface lay a critical issue: the absence of accurate as-built documentation. 

The bridge, operational for years, had never undergone a full digital survey. Original design drawings were outdated or missing entirely. For a structure still in active use, this lack of data posed real-world risks: 

  • Difficulty in planning structural assessments 
  • Potential rework due to undocumented geometry 
  • Delays in retrofit and maintenance scheduling 

These challenges pointed toward the need for a digital transformation of the structure. This is where Tejjy Inc. Deployed its expertise in 3D laser scanning and Scan-to-BIM services to create a data-rich digital twin of the bridge.  The outcome not only resolved documentation gaps but also empowered MCDOT with actionable intelligence for future planning and risk mitigation. 

The Solution: High-Precision 3D Laser Scanning & BIM Implementation 

Addressing the challenges posed by the Garage 49 Pedestrian Bridge required a tailored approach that balanced technical precision with operational sensitivity. The Montgomery County Department of Transportation (MCDOT) sought a solution that would provide accurate as-built documentation without disrupting daily pedestrian traffic. Leveraging our expertise in Scan-to-BIM services, Tejjy Inc. devised and executed a strategy that met these objectives effectively.  

Client Requirements: 

  • Accurate As-Built Documentation: MCDOT needed precise digital records of the bridge to inform maintenance and future renovation projects.  
  • Minimal Public Disruption: Given the bridge’s continuous use, it was imperative that data collection methods did not impede pedestrian movement.  

Execution Challenges 

1. Complex Structural Geometry 
The bridge’s unique design and aged components posed difficulties in capturing complete, accurate data. Irregular forms, tight angles and under-bridge elements required multi angle scanning.  

2. Active Public Usage 
As the bridge remained operational, safety and access for pedestrians had to be maintained. Tejjy scheduled scans during off-peak hours and implemented a non-invasive workflow, ensuring zero disruption to daily use. 

3. Integration with MCDOT Systems 
To support long-term asset management, the point cloud was georeferenced to NAD83 and translated into a LOD 500 BIM model fully compatible with MCDOT’s GIS and infrastructure systems for future maintenance and planning. 

Tejjy’s Strategic Approach: 

  • Advanced-Data Acquisition:  

We employed our advanced laser scanning equipment Leica RTC360 and BLK360 laser scanners, renowned for their rapid and precise data capture capabilities. These tools allowed us to document the bridge’s existing conditions with sub-centimeter accuracy.  

  • Operational Planning:  

To address the challenge of continuous pedestrian traffic, our team scheduled scanning sessions during off-peak hours. This strategy minimized public inconvenience and enhanced on-site safety.  

  • Data Processing and Integration:  

Post-capture, the point cloud data underwent rigorous processing and was georeferenced to NAD83 standards. This ensured that the digital models aligned accurately with geographic coordinates, facilitating integration into MCDOT’s GIS and asset management platforms.  

  • Development of Detailed BIM Models: 

From the processed data, we crafted a Level of Detail (LOD) 500 Building Information Model (BIM). This model provided an exact digital twin of the bridge, encapsulating every structural nuance and serving as a reliable foundation for future assessments and interventions.  

Through this comprehensive approach, Tejjy Inc. fulfilled MCDOT’s immediate needs and also equipped them with a reliable and smart digital asset.  

Outcomes & Benefits: Optimizing Cost, Time, and Asset Performance 

The application of Tejjy’s Scan-to-BIM approach delivered measurable improvements across multiple dimensions of project performance: 

  • Time Savings:  
  • Industry research indicates that Scan-to-BIM can reduce overall project timelines by up to 12%, thanks to faster documentation, reduced field visits, and streamlined data sharing among stakeholders. 
  • Cost Reduction:  
  • Accurate digital data significantly reduces the risk of errors during planning and execution.  
  • Improved precision helped minimize rework and last-minute change orders, resulting in an estimated 5–7% reduction in total project costs. 
  • Operational Clarity:  
  • The final BIM model, developed at LOD 500, empowers MCDOT with a long-term digital asset.  
  • The model can now support structural evaluations, safety audits, maintenance planning, and future retrofits, with every component mapped and verified. 
  • Geospatial Compatibility:  
  • By georeferencing the model to NAD83 standards, the asset is fully aligned with MCDOT’s GIS-based infrastructure management systems, supporting a more integrated, future-ready asset network. 

Conclusion: Laying the Foundation for Digital Infrastructure Management 

Through the digitization of the OGTR and Edgemoor Lane Pedestrian Bridge, Tejjy Inc. not only addressed an immediate data gap but also established a foundation for long-term digital asset management. As an 8(a)-certified AEC firm specializing in digital construction for federal and public infrastructure, Tejjy was selected by MCDOT to ensure that this critical pedestrian link could be preserved and modernized using the best available technology. 

This project stands as a testament to the transformative value of Scan-to-BIM in modern infrastructure practice. By turning outdated, undocumented structures into data-rich digital twins, public agencies can plan with clarity, act with precision, and invest in safer, smarter communities.