Advanced Technology for Large Structural Systems
A National Engineering Research Center

ATLSS Infrastructure Monitoring Program

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Lehigh University’s ATLSS Infrastructure Monitoring (AIM) program is internationally recognized as a leader in the field testing and evaluation of bridges and related structures and continues to advance the state of the art in this field. Although the University’s structural engineering faculty, mainly under the direction of emeritus faculty Dr. John W. Fisher and Dr. Ben T. Yen, had performed countless field instrumentation projects on bridges and other transportation structures over the previous three decades, it was during the late 1990s that researchers at the ATLSS Engineering Research Center realized that the owners of various transportation systems had more definitive needs, both research and task oriented. In 2000, the operations of the Center’s AIM program formally began.

Over the past eleven years, the AIM program’s faculty and research staff have conducted or been involved with field evaluations and failure analysis of major bridge structures and other infrastructure systems throughout the United States. Bridge owners have sought technical support for projects that included load testing and long-term monitoring of a variety of bridge types, including tied-arch, plate-girder, suspension, and truss and have often contacted the AIM program to validate the in-situ fatigue performance of a new design. The program has also been commonly contracted to evaluate the cause of observed cracking or estimate the remaining fatigue life of uncracked details. Load testing has also been successfully used to improve bridge rating analyses.

The AIM program, currently under the direction of ATLSS Director and Joseph T. Stuart Professor of Structural Engineering Richard Sause, continues to utilize its expertise to support the engineering needs of bridge and other infrastructure systems owners throughout the United States.


The expertise of the AIM program encompasses:

  • Controlled load testing and structural evaluation

  • Remote sensing and long-term health monitoring

  • Fatigue and fracture analysis

  • Development of fatigue rehabilitation and retrofit concepts

  • Modeling, simulation, and prediction of behavior through finite element analysis

  • Data reduction, analysis, and interpretation

  • Dynamic testing (forced-vibration, ambient vibration monitoring)

  • Material testing and evaluation


The AIM program owns a fully equipped field testing vehicle, a Dodge Sprinter S3500 cargo van with high roof and extended wheelbase, which provides extreme mobility and flexibility to respond to project demands upon short notice. This vehicle is equipped with a mobile office and stores a cache of tools, instrumentation, and other supplies regularly required for field monitoring projects.

The data acquisition and instrumentation capabilities include:

Rugged high-speed multi-channel digital data acquisition systems equipped with advanced signal processing capabilities

  • Rainflow cycle counting for fatigue evaluations

  • Wireless remote sensing

  • Remote data collection

  • Wide array of high fidelity sensors capable of measuring load, strain, displacement, acceleration, rotation, temperature, wind speed and direction

  • Digital video cameras with remote pan, zoom and tilt operations; a 4 channel digital video recorder (DVR) can be configured for continuous video monitoring.

AIM Program Contacts

Specific technical interest/inquiries regarding the program can be addressed to either of the following program research personnel:


Ian Hodgson, Research Engineer III, ATLSS Engineering Research Center

Phone: 610-758-3293



General program inquiries can be addressed to:

Joseph Saunders, Associate Director of Operations, ATLSS Engineering Research Center

Phone: 610-758-3223