AKTAN’s RESEARCH QUESTIONS:

1. REALITY of CONSTRUCTED SYSTEMS?: Geometry, Matls and internal reactions at commissioning; external and intrinsic loading mechanisms; how the loads are distributed, likely failure modes and capacity for various extreme loading scenarios; and how these change

with age, deterioration and damage.

2. Heuristic Knowledge (HK):From observing, hypothesizing, accumulating and synthesizing experiences. How to capture HK?

3. Mathematical modeling of REALITY:Understanding basic mechanisms thru whichstructural materials and elements are stressed,strained and fail via generalized differential equations formulated through mechanics and/or thermodynamics. PLATONIC REALITY!

5. Numerical Simulation of REALITY: Analytical and Computational Model(s) at macroscopic-meso level-microscopic Scales. Calibration and Validation of a DIGITAL TWIN for Scenario and Failure Mode Analysis, Hazards risks, Management Decisions for Maintenance, Retrofit and Renewal

4. Exploring how close we may approach REALITY by transforming the field into a Physical Laboratory. Capturing and analyzing data from infrastructures by imaging-sensing-communication-and computing systems:1. Materials sampling and testing in lab 2. Short-term Operational Monitoring for

vibrations, strains, disps, tilts3. Local/Regional NDE Scans 4. Controlled Dynamic Testing 5. Controlled Static Load Testing6. Long-Term Operational Monitoring of

Health and Performance7. Other tech tools and paradigms

6. Business Case & Management Decisions: 1. Benefit/Cost of investing into REALITY?2. How to leverage REALITY for generic

knowledge on similar infrastructures?1. Value at Risk if REALITY is not sought?2. Evaluation of Uncertainty, Risk, Resilience.

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Shahrooz, B.M., Ho, I.K., Aktan, A.E., Borst, R., Blaauwendraad, J., Veen, C., Iding, R.H. and Miller, R.A., “Nonlinear Finite Element Analysis of a Deteriorated Slab Bridge,” Journal of Structural Engineering, ASCE, February 1994.

Prediction Errors:>100%Simulation: As Shown after (a) Modeling the Constraint MechanismsAnd Kinematics at the Slab-Abutment Boundaries(b) Calibration of the BoundarySpring Stiffnessesand Concrete Properties© Failure modeand mechanismcould not be simulated

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Naghavi, R. and Aktan, A.E., “Nonlinear Behavior of Existing Heavy-Class Steel TrussBridges,” Journal of Structural Engineering, Vol. 129, No. 8, August, 2003.

Shelley, S.J, Lee, K.L., Aksel, T. and Aktan, A.E., “Active Control and Forced Vibration Studies on a Highway Bridge,” Journal of Structural Engineering, September 1995.

Aktan, A.E., Helmicki, A.J and Hunt, V.J., “Issues In Health-Monitoring For Intelligent Infrastructure,” Journal of Smart Materials and Structures, October 1998, pp: 674-692.

Aktan, A.E., Farhey, D.N., Helmicki, A.J., Brown, D.L., Hunt, V.J., Lee, K.L. and Levi, A., “Structural Identification for Condition Assessment: Experimental Arts,” Journal of Structural Engineering, ASCE, Vol. 123, No. 12, Dec., 1997.

Aktan

A.E., C

atbas, N

., Turer, A

., and

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g, Z., “Structu

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. 7, Ju

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Lenett, M.S., Griessmann, A., Helmicki, A.J., and Aktan, A.E., “Subjective and Objective Evaluations of Bridge Damage,” TRR No. 1688, pp: 76-86, NAP, Washington, D.C., 1999.

Aktan, A.E., Dalal, V., Farhey, D., Helmicki, A., Hunt, V., and Shelley, S., “Condition and Reliability Evaluation for Bridge Management,” Journal of Infrastructure Systems, Vol 2, No. 3, Sep. 1996.

F. Necati Catbas and A. Emin Aktan, Structural Identification and Performance Monitoring System for a Long-Span Cantilever Truss Bridge, Encyclopedia of Structural Health Monitoring, John Wiley & Sons, Ltd, Great Britain, 2007.

M. T. Yarnold, F.L. Moon, and A. E. Aktan, “Temperature-Based Structural Identification ofLong-Span Bridges J. Struct. Eng., 2015, 141(11)

Live Portals for Remote Data Viewing and InterpretationDuring Opening

Playbacks –Interrogation and Interpretation of Triggered Events

Advanced Visualization and Accessibility to Heterogeneous Monitoring DataB. Glisic, M. T. Yarnold, Franklin L. Moon & A. Emin AktanComputer-Aided Civil and Infrastructure Engineering 00 (2014) 1–17

K. Grimmelsman, Q. Pan and A. E. Aktan, Analysis of Data Quality for Ambient Vibration Testing of the Henry Hudson Bridge, Journal of Intelligent Material Systems and Structures, 2007, Vol 18, Issue 8. A

.E. Aktan

, S.K. C

iloglu

, K.A

. Grim

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.Pan, F.N

. Catb

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Reliability of a-Priori Models of Large Structural Systems:

Q. Pan, K. Grimmelsman, F.L. Moon and A.E. Aktan “Mitigating Epistemic Uncertainty in Structural Identification,” Journal of Structural Engineering, Vol. 137, No. 1, January, 2011.J. Zhang, J. Prader, K.A. Grimmelsman, F. Moon and A.E. Aktan; with, Shama, A. “Experimental Vibration Analysis for Structural Identification of a Long Span Suspension Bridge,” Journal of Engineering Mechanics, Vol. 139, No. 6, June, 2013.

Leveraging Technology for Infrastructure Condition and Performance AssessmentAktan, Moon and Weidner, Front. Built Environ., 2016. https://doi.org/10.3389/fbuil.2016.00036

•Rapid modal impact testing by a mobile device•Capable of single controlled impact of 30 Kips •Semi-Automated pre- and post-processing to obtain global frequencies and mode shapes•Automated FE modeling using NBI data and on-site assessment•Automated FE model calibration and load rating

Drs. Moon, Aktan, et al: Targeted Hits to Measure Performance Responses (THMPR) has been selected by the American Society of Civil Engineers to receive the 2017 Charles Pankow Award for Innovation.

DREXEL’S THUMPER

Zhou, Y., J. Prader, J. DeVitis, D. Masceri, A. Deal, F.L. Moon and A.E. Aktan (2011) “Rapid Bridge Modal Analysis for Global Structural Assessment,” Experimental Vibration Analysis for Civil Engineering Structures (EVACES), Verenna, Italy

Low-Powered Wireless Sensors for Asset Management or Health Monitoring of Structures and Pavements”; FHWA - EARP, Bartoli and Aktan, 2013-2018.Virtual Nondestructive Evaluation (NDE) Laboratory for Highway Structures”; FHWA - EARPBartoli and Aktan, 2016-2019.

Virtual Laboratory for Leveraging Technology for Bridges and Constructed Systems, Aktan, Bartoli, et al, EVACES 2017.