Research

Research Themes

Current Research

Connection Behavior in Steel Structures​

-- Overview: Investigate the behavior of steel connections with bolts and welds sharing the load. This combinational joints can be desirable during retrofit of existing structures.
​       The behavior of this type of connection is currently being investigated through extensive experimental testing and numerical finite element analysis to characterize the effect of bolt type, load eccentricity, and connection size, among others. Additionally, probabilistic analysis and stochastic modeling will be performed to quantify the uncertainties associated with the performance of this type of connections.

-- Key Experiment Components:
  • Two custom load frames (500kip & 1500kip)
  • Powered by 565 ton hydraulic cylinders
  • Digital image correlation method to investigate strain field
  • 100+ specimens will be tested

-- Sponsors:
  • American Institute of Steel Construction  (AISC)
  • ​W &W AFCO Steel
  • St. Louis Screw & Bolt
  • GWY
  • ​Skidmore Wilhelm
Steel connection  specimen with fractured weld
500 kip testing frame for investigating the behavior of combination connections
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--Related Projects:
  • Understanding the Behavior of Steel Connections Made in Combination of Bolts and Welds, AISC, 2017-2019 (with Co-PI Bruce Russell)

Performance Evaluation of Civil and Marine Structures Under Fatigue Deterioration

-- OverviewFatigue is one of the major factors that may influence the safety of civil and marine structures. The presence of significant uncertainties related to loads, geometry, and material properties affects our ability to reliably predict the time-dependent performance of structures under fatigue deterioration. Probabilistic approaches can aid in predicting the time-dependent performance of structures under fatigue deterioration considering uncertainties. Moreover, reliability and risk-based management techniques can be used to predict the safe service life of fatigue sensitive structures, plan for their future inspections, and support the decision-making process regarding maintenance and repair actions.​​ 
​       This research develops a framework that can be implemented on civil and marine structures under cyclic loadings (e.g. bridges and ships) to determine their service life and the uncertainty associated with it. This approach can be used by the managers to schedule optimum maintenance and repair actions, thereby increasing the service life of the structure and reducing the cost and frequency of maintenance.

-- Sponsor:
  • Office of Naval Research (ONR)
Damage accumulation at different operational conditions heading angle

--Related Projects:
  • An Integrated Framework for Prediction of Fatigue Crack Propagation under Random Sea Loading Through Coupled Experimental and Numerical Analysis, ONR, 2018 – 2021​
High-Speed Naval Craft HSV 2
http://en.wikipedia.org/wiki/HSV-2_Swif

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Sustainability-Based Management of Bridges

-- Overview:  Formulate a sustainability-based management approach for bridges under multiple hazards. Considered hazards are primarily hydraulic related (e.g., floods, inundation, and scour) and seismic events, in addition to gradual deterioration due to corrosion in the sub-structure and super-structure. The goals of the research are:
  • Develop a comprehensive integrated tool to assess the fragility and risk of failure for bridges under multiple hazards 
  • Formulate an approach for optimal decision-making under uncertainty to establish optimum management activities of bridges considering sustainability and resilience metrics
  • Establish a detailed guidebook for optimal sustainability-based management of deteriorating bridges

-- Sponsors: 
  • Transportation Consortium of South Central States (Tran-SET) ​
  • ​Southern Plains Transportation Center (SPTC) 
--Related Projects:
  • ​​Sustainability-based Long-term Management of Bridges under Multi-hazards Exposure, Tran-SET, 2017 – 2018
  •  Application of Fiber Optic Sensors for Monitoring Prestressed Concrete Bridges, SPTC, 2017-2018 (with Co-PI Royce Floyd)
  • Risk-based Life-cycle Management of Deteriorating Bridges, SPTC, 2016 – 2017 (with Co-PI Julie Ann Hartell)
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Life-cycle Analysis of Transportation
Infrastructure

-- Overview:​​ Bridges are under continuous deterioration due to aggressive environmental conditions, mechanical stressors, and de-icing salts. Addressing the problems arising from this deterioration requires frequent maintenance and repair operations that not only increase the operational cost of the structure, but also often lead to traffic delays and their associated impacts on the economy and environment.​​ The optimum material selection for constructing new structures or rehabilitating existing ones should be based on comprehensive life-cycle cost analysis capable of considering direct and indirect impacts associated with individual solutions. 
       This research constructs implementable life-cycle cost analysis approaches that can help infrastructure managers apply these concepts for informed decision making regarding bridge construction materials. Applications include steel and reinforced concrete bridges.

-- Sponsor:
  • ​​Transportation Consortium of South Central States (Tran-SET) 
--Related Projects:
  • Life-Cycle Cost Assessment of Reinforced Concrete Bridge Decks  Constructed using Regular and Corrosion Resistant Reinforcement, Tran-set, 2018 – 2019 (with co-pi Samir Ahmed)
Probabilistic life-cycle cost of a steel bridge using  regular and corrosion resistant steel​​
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