[PhD Defense] Edward Eskew

Edward Eskew

PhD dissertation

Department of Civil & Environmental Engineering

University of Connecticut 1:00 PM. – Thursday, July 27, 2017

CAST 306

Advisory Committee:

Dr. Shinae Jang (Major Advisor)

Dr. Michael Accorsi (Associate Advisor)

Dr. Richard Christenson (Associate Advisor)

Dr. Jeongho Kim (Associate Advisor)

Dr. Wei Zhang (Associate Advisor)

Structural Health Monitoring of Civil Structures for Safety Assessments from Explosions

ABSTRACT

 Due to unstable political climates across the world, the potential for terrorist attacks against civil infrastructure has become a serious concern. The increasing threat of explosions has fueled the need for research into methods to rapidly, and safely, assess the condition and safety of a structure from a blast. The ability to assess the structures safety from a potential blast with cumulative structural damage can be used to update security operations or retro-fit elements to improve resilience. This research shows how to update a structural model with experimental measurements to develop updated safety assessments for structures from blasts which incorporate the current structural condition.  After an explosion has occurred, one of the key structural failures is a progressive collapse of the structure. To assess a structures probability of failure after an explosion, a method is developed which uses structural health monitoring (SHM) techniques to update a numerical model with vibration measurements to represent the damaged condition of a structure after a blast, and to assess probability of failure using the alternate path method. The proposed method is threat-independent, in that it does not require any information regarding the blast event. As the methodology utilizes vibrational measurements, the gathered information is critical to the condition assessment. However, the number of monitoring sensors is usually significantly less than the number of potential monitoring degrees-of-freedom (DOF), and there is a significant potential for malfunctioning sensors due to the blast event. To quantify damage in a structure with damaged sensors, a two phase remaining stiffness localization and quantification method for limited measurements is presented. And, two optimal sensor placement (OSP) methods are used to demonstrate the proposed two phase parameter localization and quantification method ability to quantify changes in a structure using a limited number of sensors