Education

Research Description

The general research interest of Dr. Rizkalla is in the design, construction and behavior of reinforced concrete and prestressed concrete structures and bridges. During the last thirty years, his research interest has focused on the use of higher performance concrete and fiber reinforced polymer (FRP) materials for the construction, repair and strengthening of structures and bridges. His current research interests include diagnostic and prognostic of structure and bridges using non-destructive monitoring systems.

Honors and Awards

• ACI Charles Whitney Award, 2016
• The FRPRCS-12 / APFIS 2015 Award for Best Paper, 2015
• Chester Paul Siess Award for Excellence in Structural Research, American Concrete Institute, 2014
• T.Y. Lin Award, American Society of Civil Engineers, 2013
• Charles C. Zollman Award, Precast/Prestressed Concrete Institute, 2012
• Best paper and best Poster in the APFIS 2012 Conference, 2012

Publications

Long-term behavior of precast, prestressed concrete sandwich panels reinforced with carbon-fiber-reinforced polymer shear grid

Nafadi, M. K., Lucier, G., Yaman, T. S., Gleich, H., & Rizkalla, S. (2021), PCI JOURNAL, 66(5), 23–38. https://doi.org/10.15554/pcij66.5-01

Durability of CFRP strands used for prestressing of concrete structural members

Khalafalla, O., Pour-Ghaz, M., ElSafty, A., & Rizkalla, S. (2019), CONSTRUCTION AND BUILDING MATERIALS, 228. https://doi.org/10.1016/j.conbuildmat.2019.116756

CFRP shear strengthening system for steel bridge girders

Kazem, H., Zhang, Y., Rizkalla, S., Seracino, R., & Kobayashi, A. (2018), ENGINEERING STRUCTURES, 175, 415–424. https://doi.org/10.1016/j.engstruct.2018.08.038

Effects of Basalt Fibres on Mechanical Properties of Concrete

El-Gelani, A. M., High, C. M., Rizkalla, S. H., & Abdalla, E. A. (2018), MATEC Web of Conferences, 149, 01028. https://doi.org/10.1051/MATECCONF/201714901028

Effects of Basalt Fibres on Mechanical Properties of Concrete

El-Gelani, A. M., High, C. M., Rizkalla, S. H., & Abdalla, E. A. (2018), MATEC Web of Conferences, 149, 01028. https://doi.org/10.1051/MATECCONF/201814901028

Shear strengthening of steel plates using small-diameter CFRP strands

Kazem, H., Rizkalla, S., & Kobayashi, A. (2018), COMPOSITE STRUCTURES, 184, 78–91. https://doi.org/10.1016/j.compstruct.2017.09.094

New generation of precast concrete double tees reinforced with carbon-fiber-reinforced polymer grid response

Lunn, D., Lucier, G., Rizkalla, S., Cleland, N., & Gleich, H. (2017), PCI Journal, 90–91.

Behavior of Free and Connected Double-Tee Flanges Reinforced with carbon-fiber-reinforced polymer

Botros, A., Lucier, G., Rizkalla, S., & Gleich, H. (2016), PCI Journal.

Do mechanical and environmental loading have a synergistic effect on the degradation of pultruded glass fiber reinforced polymers?

Pour-Ghaz, M., Miller, B. L. H., Alla, O. K., & Rizkalla, S. (2016), COMPOSITES PART B-ENGINEERING, 106, 344–355. https://doi.org/10.1016/j.compositesb.2016.09.007

Improved Mode I fracture resistance of CFRP composites by reinforcing epoxy matrix with recycled short milled carbon fibre

Cholake, S. T., Moran, G., Joe, B., Bai, Y., Raman, R. K. S., Zhao, X. L., … Bandyopadhyay, S. (2016), CONSTRUCTION AND BUILDING MATERIALS, 111, 399–407. https://doi.org/10.1016/j.conbuildmat.2016.02.039

View all publications via NC State Libraries

Grants

Center for Integration of Composites into Infrastructure Membership (CICI), Full Member

DowAksa (7/01/16 - 6/30/17)

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member

Sponsor: DowAksa

Start Date: 7/01/16

End Date: 6/30/17

Abstract

Full Membership

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member with special service privileges

CarbonOne Technologies, Inc.(11/16/15 - 6/30/16)

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member with special service privileges

Sponsor: CarbonOne Technologies, Inc.

Start Date: 11/16/15

End Date: 6/30/16

Abstract

Full Member with special service privileges

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Testing Proposal for Three-Wythe Push Tests of Wall Panel Segments Reinforced with CFRP Grids, Core Project 7

Center for Integration of Composites into Infrastructure (CICI) - NCSU Research Site(7/01/14 - 6/30/16)

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Testing Proposal for Three-Wythe Push Tests of Wall Panel Segments Reinforced with CFRP Grids, Core Project 7

Sponsor: Center for Integration of Composites into Infrastructure (CICI) - NCSU Research Site

Start Date: 7/01/14

End Date: 6/30/16

Abstract

The primary purpose of the testing program would be to evaluate the ICC acceptance criteria currently in development for continuous or semi-continuous fiber-reinforced grid connectors anchored in concrete. In addition, data generated would be useful in characterizing the shear flow capacity of CGRID sandwich panel connections in various configurations.

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Development of Rational Design Methodologies for Dapped Ends of Prestressed Concrete Thin- Stemmed Members, CICI Enhancement Project

Precast/Prestressed Concrete Institute(7/01/14 - 12/31/15)

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Development of Rational Design Methodologies for Dapped Ends of Prestressed Concrete Thin- Stemmed Members, CICI Enhancement Project

Sponsor: Precast/Prestressed Concrete Institute

Start Date: 7/01/14

End Date: 12/31/15

Abstract

The goal of the proposed research is to develop standard details for typical dapped end prestressed thin stemmed-members. The research scope includes extensive non-linear finite element analysis and full scale experimental. The investigation will examine existing test data, published literature, current design guides, advanced computer analyses, and experimental testing. Based on these results, the research will develop a comprehensive set of appropriate and practical design procedures and reinforcement details suitable for implementation.

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Behavior and Design of Directly-Loaded L-Shaped Beam Ledges, CICI Enhancement Project

Precast/Prestressed Concrete Institute(7/01/14 - 6/30/16)

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Behavior and Design of Directly-Loaded L-Shaped Beam Ledges, CICI Enhancement Project

Sponsor: Precast/Prestressed Concrete Institute

Start Date: 7/01/14

End Date: 6/30/16

Abstract

The goal of the research project is to test short-span beams to investigate the influence of different reinforcement details.

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Center for Integration of Composites into Infrastructures (CICI), Full Member with Special Service Privileges

AltusGroup, Inc.(7/01/14 - 6/30/15)

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Center for Integration of Composites into Infrastructures (CICI), Full Member with Special Service Privileges

Sponsor: AltusGroup, Inc.

Start Date: 7/01/14

End Date: 6/30/15

Abstract

Membership

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member

Mag Phos, Inc. (MPI)(1/01/13 - 6/30/15)

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member

Sponsor: Mag Phos, Inc. (MPI)

Start Date: 1/01/13

End Date: 6/30/15

Abstract

Memberships

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CFRP Strands in Prestressed Cored Slab Units

NC Department of Transportation(8/16/13 - 5/08/15)

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CFRP Strands in Prestressed Cored Slab Units

Sponsor: NC Department of Transportation

Start Date: 8/16/13

End Date: 5/08/15

Abstract

Prestressed concrete cored deck slabs are a common bridge component used by the NCDOT for spans as long as 60 ft. Cored deck slabs efficiently serve as both the bridge superstructure and the deck when placed side-by-side, spanning between bents. Bridges utilizing cored slabs are often subjected to deicing salts, or may be located in the vicinity of saltwater or brackish water. When exposed to moisture and salts, the prestressing and mild steel reinforcement inside any reinforced concrete structure will deteriorate, reducing structural capacity. The problem of corrosion can be exacerbated in cored deck slabs due to the potential for corrosive products to penetrate the cores via the top of the slab, causing corrosion to develop from the interior of the structure. This internal corrosion would not likely be spotted by a visual inspection. Fiber-reinforced polymer (FRP) materials have the potential to improve the durability of cored deck slabs when used as a replacement for traditional mild steel and prestressing strands. FRP strands and bars are a proven non-metallic alternative to steel that have the advantage of being highly corrosion resistant. In addition to their corrosion resistance, FRP materials can offer strengths up to 3-5 times stronger than mild steel at approximately 1/5th the density. The proposed research project will assess the suitability of replacing steel prestressing strands in cored deck slabs with carbon fiber composite cable (CFCC) strands. In addition, the proposed research will investigate using glass fiber reinforced polymer (GFRP) bars as a replacement for conventional mild steel reinforcement in cored deck units (stirrups and supplemental mild steel reinforcement). Producing a cored deck slab with CFCC strands and conventional mild steel transverse reinforcement would negate many of the benefits offered by the CFCC strands. Thus, an all-FRP solution will be developed, validated with full-scale laboratory testing, and documented with design recommendations and examples. Specifically, the research team will: ?h Conduct a detailed literature review to determine available test data, design recommendations, and guidelines that may be relevant for the use of CFCC strands and GFRP reinforcement in cored deck slabs. ?h Develop an approach for designing cored deck slabs using FRP strands and transverse reinforcement. ?h Design several sample cored deck slabs using the developed approach, assuring that all designs remain compatible with conventional production techniques and NCDOT standard details. ?h Develop designs for a series of cored deck slab specimens to be tested experimentally to validate the concept of using FRP for both prestressed and conventional reinforcement. ?h Develop a system for producing FRP-reinforced cored deck slabs using conventional fabrication techniques. In particular, details related to stressing CFCC strands will be implemented. ?h Document the production of full-scale cored deck specimens. ?h Conduct full-scale laboratory testing and analyze the test results. ?h Document the research program in a technical report, including design recommendations and an implementation plan. The outcomes of this research project will provide the NCDOT with the tools required to design and evaluate the performance of FRP-reinforced prestressed cored slabs. The enhanced durability of such systems can be evaluated in life-cycle cost analyses to quantitatively compare alternatives.

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Developmnent of Rational Design Methodologies for Dapped Ends of Prestressed, CICI Core Core Project 6

Center for Integration of Composites into Infrastructure (CICI) - NCSU Research Site(7/01/12 - 12/31/14)

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Developmnent of Rational Design Methodologies for Dapped Ends of Prestressed, CICI Core Core Project 6

Sponsor: Center for Integration of Composites into Infrastructure (CICI) - NCSU Research Site

Start Date: 7/01/12

End Date: 12/31/14

Abstract

Memberships:Precasted double tees with thin stems are a widely used and highly successful floor member in parking structures and other buildings. Frequently, the end supports are dapped such that the bottom of the double tee is level with the bottom of the inverted tee or ledge beam on which it is supported. The dapped connection detail is especially important at cross overs between spans in parking structures because the overall structural depth and floor-to-floor height need not be increased where the double tee is supported by and inverted tee beam. While the title of the research project implies the primary objective is the ?development of rational design methodologies,? the RFP also discusses the need for industry standard details for dapped double tees. Both objectives are appropriate. Rational design methodologies are needed to proportion reinforcement in the dapped end, and standard industry details are needed to assure effectiveness and constructability. Thus, the objective of this research is twofold: 10 develop rational methodologies for proportioning key reinforcements in dapped end double tees, and 2) develop standard details that been rigorously reviewed by industry experts and have proven to be effective by extensive analyses and tests.

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member

Wiss, Janney, Elstner Associates, Inc.(7/01/12 - 6/30/14)

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Center for Integration of Composites into Infrastructure Membership (CICI), Full Member

Sponsor: Wiss, Janney, Elstner Associates, Inc.

Start Date: 7/01/12

End Date: 6/30/14

Abstract

Memberships

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