Sami Rizkalla

The project investigates the effectiveness of using Grancrete paste as an alternative to epoxy resins for the adhesion of fiber strengthening to reinforced concrete structures. The study includes also evaluation of the fundamental bond characteristics and permeability of the Grancrete material.

CICI intends to usher applications and cost-effective solutions using composite material systems and technologies in the fields of civil and military structures.

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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.

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

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.

The proposed research topic is related to the design and behavior of precast concrete Ledge Beams.

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Applications of Fiber Reinforced Polymer (FRP) composites made of thermosets and thermoplastics have been growing steadily. According to ACMA, construction and transportation infrastructure industries account for over 50% of the composites made from 4.11 billion lbs/year of thermoset resins. Even though FRP composites can provide longer-service life because of more beneficial thermo-mechanical performance over conventional materials, lack of understanding of durability and life-cycle performance is a major technical obstacle for their high volume application. The durability response is identified typically in terms of chemical, physical and mechanical aging and their combinations. Experimental data on aging is not well documented and even difficult to access; hence, unsubstantiated safety factors are being used in design of composite structures. These factors have the potential for over- or under- designing because of improper understanding of failure mechanisms. Therefore, the following objectives of the proposed research on FRP composites are identified based on priorities of the NSF I/UCRC CICI (Center for Integration of Composites into Infrastructures) industrial members and end-users (see IAB chair Dr. Miller?s letter for industrial support and the attached LIFE form Table): i) evaluate mechanisms that lead to the degradation of pultruded and infused composite material properties at micro- and macro-levels (coupons and components); ii) minimize manufacturing (pultrusion vs. infusion) and durability related defects, including debondings to ensure composite integrity and durability; and iii) develop a unified model(s) to predict life-cycle performance of polymer composites using the fundamental principles of mechanics and thermodynamics so that a master curve(s) with vertical shift factors (strength degradation) can be developed as a function(s) of time, temperature and pressure. Field data from several composite industries and government agencies will be obtained (as per appended letters from industry) and integrated with the proposed research data to be generated by testing 207 samples under controlled aging conditions. Intellectual Merit: Many investigators have conducted research on aging of composites under one or combination of two aging parameters (time, temperature, moisture, freeze-thaw, pH, sustained stress, fatigue, creep/relaxation, UV etc.); however, this research not only proposes to experimentally evaluate aging responses under the combined action of several aging parameters, but also proposes to develop a ?unified theory? based on internal strain energy dependent degradation as the fundamental damage metric since it is most sensitive to changes in material response. Over 200 environmentally conditioned specimens are proposed to be tested for collecting laboratory data in a systematic experimental design and for the first time ever, field data will be collected in collaboration with major industries and end-users so as to arrive at accurate and properly weighted calibration of FRP aging trends. Broader Impact: The proposed topics defined in consultation with CICI?s IAB lead to: i) quantifying the behavior of FRP composite constituents at micro- and macro-levels under the synergistic influence of hygro-chemo-thermo-mechanical loads and manufacturing of highly durable composites; ii) improving the efficiency of design of FRP structures and promoting safe design guidelines based on sound knowledge of synergistic effects and durability principles; iii) fulfilling the product durability in mass manufacturing; and iv) specification development that is required by manufacturers, allied industries, and end-users. Two graduate students will be trained to work on the research activities and the students will be working as interns in major industries, e.g., Ashland Chemicals, AEP, BRP, and others. More importantly, many more well-paid skilled labor jobs will be created by corporate America upon the completion of the project due to the ability to produce durable composites on a high-volume basis to repair and st

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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.

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.

Efficient infrastructure systems such as highways, bridges, buildings, pipelines, flood control systems and utilities are all necessary for a healthy economy and comfortable standard of living. The proposed Center will focus on new research concerning: ) development of constituent material combinations for optimum end products, 2) cost-effective ways to manufacture products, 3) green production, including the use of bio-fiber and resins and industrial byproducts, 4) further development and application of standard test procedures, guide-specifications, design methods and rapid, modular construction techniques in addition to continuing research started by RB2C concerning the development of innovative and sustainable structural materials and systems for infrastructure applications, renewal of existing infrastructure , load testing and assessment of constructed facilities, and structural health monitoring and prognostics.

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The proposed research program investigates the use of fiber reinforced polymer (FRP), produced in Korea, to achieve the composite action of precast and possibly prestressed concrete sandwich panels. The panels could be used as load bearing and/or non-load bearing architectural panels. The panels typically consist of two outer concrete wythes and an interior foam core. The research program will focus on the shear flow capacity of the insulating materials in combined action with the Korean FRP grid proposed to achieve the composite action. The study will include several parameters believed to affect the behavior, the structural efficiency, and the thermal efficiency of the panels as described briefly in this summary of the research program. Testing of the full scale panels to study the effectiveness of the proposed system will be conducted at the Korea Institute of Construction Technology located in Goyang, Gyeonggi. The research at North Carolina State University (NCSU) will consist mainly of testing small scale panels to examine and evaluate the behavior of the proposed system as affected by several parameters believed to affect the behavior and the shear capacity. The tests are intended to follow the requirements of the criteria recently approved by the International Code Council (ICC) AC422-1010-R3 ?Acceptance Criteria for Semi-Continuous Fiber Reinforced Grid Connectors Used in Combination with Rigid Insulation in Concrete Sandwich Panel Construction.?

The proposed research program investigates the use of fiber reinforced polymer (FRP) materials, produced in Korea, to achieve the composite action of an innovative precast and possibly prestressed concrete sandwich panels. The panels could be used as load bearing panels or non-load bearing architectural panels. The panels typically consist of two outer concrete wythes and an interior foam core. The research program will focus at North Carolina State University (NCSU) on the shear flow capacity of the use of an FRP grid , produced in Korea , in combined action of the insulating materials, to achieve the composite action. The study will include several parameters believed to affect the behavior, the structural efficiency, and the thermal efficiency of the panels as described briefly in this summary of the research program. Testing of the full scale panels , to study the effectiveness of the proposed system will be conducted at the Korea Institute of Construction Technology located in Goyang, Gyeonggi. The research at NCSU will consist mainly of testing small scale panels to examine and evaluate the behavior of the proposed system as affected by several parameters believed to affect the behavior and the shear capacity. The tests are intended to follow the requirements of the criteria recently approved by the International Code Council (ICC) AC422-1010-R3 ?Acceptance Criteria for Semi-Continuous Fiber Reinforced Grid Connectors Used in Combination with Rigid Insulation in Concrete Sandwich Panel Construction.? The proposed research consists of an experimental program including small-panel tests and an analytical approach to quantify test results into practical and simple design guidelines to determine the shear flow as affected by the various parameters considered.

CICI intends to usher applications and cost-effective solutions using composite material systems and technologies in the fields of civil and military structures.

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Efficient infrastructure systems such as highways, bridges, buildings, pipelines, flood control systems and utilities are all necessary for a healthy economy and comfortable standard of living. The proposed Center will focus on new research concerning: ) development of constituent material combinations for optimum end products, 2) cost-effective ways to manufacture products, 3) green production, including the use of bio-fiber and resins and industrial byproducts, 4) further development and application of standard test procedures, guide-specifications, design methods and rapid, modular construction techniques in addition to continuing research started by RB2C concerning the development of innovative and sustainable structural materials and systems for infrastructure applications, renewal of existing infrastructure , load testing and assessment of constructed facilities, and structural health monitoring and prognostics.

Mission Statement: CICI intends to usher applications and cost-effective solutions using composite material systems and technologies in the fields of civil and military structures.

CICI intends to usher applications and cost-effective solutions using composite material systems and technologies in the fields of civil and military structures.

CICI intends to usher applications and cost-effective solutions using composite material systems and technologies in the fields of civil and military structures.

CICI intends to usher applications and cost-effective solutions using composite material systems and technologies in the fields of civil and military structures

This proposal is developed in response to research idea 0403 on the NCDOT list of research ideas for AY 2010. The models currently used by NCDOT to calculate long-term prestress losses, camber and deflection of prestressed concrete girders, box beams, and cored slabs may be out of date. The objective of the proposed project is to evaluate the effectiveness of the current NCDOT methodologies to predict prestress losses, camber and deflection of prestressed concrete members in light of the recent development of using longer spans of bulb-tee girders and box beams as well as higher concrete strengths in the range of 8000 psi to 12,000 psi. The different tasks considered in this project include an evaluation of the current NCDOT models and other existing models including AASHTO LRFD Specifications. One of the major tasks of the project is to establish an extensive database of measured cambers and deflections of prestressed bridge girders used in recent and future projects in collaboration with NCDOT personnel in order to evaluate and calibrate the different models including conspan program. Based on the findings of the evaluation, a refined and more reliable model will be recommended for implementation by NCDOT. The project will provide the Structure Design Unit with a reliable and calibrated model for the design of prestressed concrete members and for predictions of deflections during and after construction. The duration of the proposed project is one year.

The NSF Industry/University Cooperative Research Center entitled ?Repair of Buildings and Bridges with Composites? (RB2C), is located at the Constructed Facilities Laboratory, North Carolina State University (NCSU). The Center is working in collaboration with the Center located at the University of Miami. The Center at NCSU focuses on the needs of the construction industry in development of new and innovative structural components as well as strengthening/repair methods for existing structures using advanced composite materials.

Validation of Shear and Bond Behavior of Engineered Light-Weight Concrete - RB2C Core Project 4

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Innovative Steel and Concrete Composite Members The development of lower cost, lighter weight framing systems is essential to the evolution of high-rise construction. An innovative steel-concrete composite system developed by DiversaKore has emerged as a leader in this area. The DiversaKore system utilizes a U-shaped steel section composite with cast-in-place concrete to create efficient light weight girders. These girders are typically used with hollow core precast planks or long span steel decking. The focus of this research is to evaluate the flexural and shear behavior of the DiversaKore system and to develop a procedure for design.

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Grancrete is a new family of innovative composite materials produced by a blend of magnesium oxide, potassium phosphate, ashes and fibers in the mixture. Its compounds originate from the mining industry and are nontoxic, non-hazardous, and environmentally friendly. Grancrete products may be used to modify or to replace conventional concrete. Currently there is an attempt to use these products for new building and for strengthening of concrete and masonry structures. The research in progress is designed to address the potential use of these innovative products for the construction industry with a clear understanding of their properties and limitations.

Design of Optimized Light Gauge Steel Members and Structural Systems Load-bearing light steel framing (LSF) systems have gained good acceptance to the low to mid-rise construction market in the U.S. in recent years. This construction market covers a wide range of building usage, including apartment and office buildings, hotels, and schools. To accommodate higher design loads, heavier floor systems and the loads at the lower levels of mid-rise buildings, designers have been required to either use multiple (built-up) C-shaped studs or switch to structural steel members. An alternative to this method is to utilize optimized sigma-shaped section manufactured by The Steel Network, Inc. of Raleigh, North Carolina named the SigmaStud?.

The proposed research program is designed to examine a new type of concrete as material for construction of buildings, bridges and special infrastructural applications. The initial phase of the evaluation includes tests to determine the basic material characteristics of Grancrete including compressive strength, elastic modulus, tensile strength, creep, shrinkage, and toughness of materials. The second phase will include examining the behavior of Grancrete mixed with small aggregate to enhance the overall behavior as construction materials. Based on the findings, the research will be extended to include the behavior of Grancrete reinforced with steel reinforcements and fiber reinforced polymer materials. The research plan will be examined every six months with the industrial members to finalize the research needed to optimize the use of these materials as construction material.

Innovative 3-D FRP Sandwich Panels for Transportation and Infrastructure The main objective of this research program is to evaluate the structural performance of 3-D FRP sandwich panels. The panels consist of GFRP laminates and foam core sandwich where top and bottom skin GFRP layers are connected together with through thickness fibers. The experimental program consists of three phases. Fundamental material properties in tension, shear and compression are evaluated in the first phase of the experimental program. The second phase focuses on the overall panel behavior under various loading conditions. The flexural, one-way and two-way shear behaviors of FRP sandwich panels are investigated. The third phase of the experimental program will focus on the behavior of the panels as used in the trailer industry. Two full-scale 3-D FRP sandwich panels having different thicknesses were tested under simulated truck wheel load. The main variables in this study include the density of through thickness fibers. The stiffness, load-deflection behavior and failure modes of the FRP sandwich panels were evaluated. Future Work The research team will continue to study the behavior and evaluate the engineering properties of various types of 3-D FRP sandwich panels. It is estimated that the first and the second phases of the experimental program will be completed within the next three to six months. The specimens will be subjected to different loading scenarios and boundary conditions that simulate the actual stress states in the sandwich panels. The research will be extended within the next two years to develop a finite element model for 3-D FRP sandwich panels using ANSYS. The model will be capable of predicting the behavior as well as the ultimate load carrying capacity of FRP sandwich panels. Results of the analysis will be used to customize the fabrication process according to the needs of various applications.

Achieving complete radiation shielding is important in any facility that produces radiation or uses radiation sources such as nuclear reactors, research labs that use radio-nuclides, hospitals and pharmaceutical companies that use radio tracers, and facilities with x-rays systems such as hospitals and dental practices, and major medical facilities that use gamma ray and tomographic scanners. Assessing the shielding effectiveness is determined by the nature of the facility and the maximum doses produced, thus attenuation of radiation is an important subject for the safety of personnel and the environment. Concretes are traditional shielding materials, where the effectiveness of shielding is determined by the density of the concrete mix and the thickness of used concretes. New forms of concretes may provide better shielding than traditional concretes, especially if such new forms incorporate high density metals, compositions that include percentage of highly attenuating materials, or mixed with fibrous materials to maintain moisture content and eliminate crack propagation.

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The goal of the proposed research is to develop appropriate design procedures and to simplify the detailing requirements for precast, L-shaped spandrel beams. To achieve the ojective, the following activities will be pursued: -Review, evaluate, and synthesize existing, pertinent research data and current code provisions. -Develop and carry out a research and testing program based on the concept of providing the minimum amount of reinforcement needed in the end-region of L-shaped spandrel beams to resist shear and out-of-plane web bending demands while satisfying ledge hanger steel requirements. -Develop design recommendations suitable for publication that simplify the design for shear and torsion of L-shaped spandrel beams, in both the end and the interior regions, while simplifying reinforcement detailing requirements.

The goal of this proposed project is to conduct research aimed at addressing and resolving three fundamental barriers to the widespread use of fiber reinforced polymer (FRP) reinforcement for concrete members. The first topical area of research relates to the prototypical development and validation of spiral shear reinforcement to overcome the problems inherently associated with the bending of pultruded FRP bars. From the production side, this may be accomplished by a proposed key modification in pultrusion equipment used to manufacture FRP bars. The use of spiral reinforcement should open real opportunities in the filed of flatwork. The second topical area of research deals with the development and validation of a FRP bar termination that will result in a significant shortening of FRP bar development length and allow for the replacement of cumbersome and costly L-shape end splices. The third and final topical area of research relates to the investigation of effectiveness of large-diameter single and bundled bars that would find primary use in underground construction. This phase includes the test of real size reinforced concrete members that would allow the understanding of size effects. The proposed project will be jointly undertaken by the two universities that constitute the NSF I/UCRC on Repair of Buildings and Bridges with Composites (RB2C) with the support and involvement of its industry members providing an additional opportunity for direct and meaningful collaboration.

Deterioration of civil infrastructure in general and structures in particular has been documented by several researchers and recognized by authorities as one of the most serious problems facing the civil infrastructure worldwide. In the last decade innovative structural materials including Fiber Reinforced Polymers (FRP) have set ambitious goals in the vast civil infrastructure markets. The primary objective of this proposal is to request travel funds to organize an international workshop in Egypt to help transfer the technology and disseminate the information on the use of FRP for sustainable structures. The workshop is organized on the premise that the exchange of existing American and Egyptian experience in the area of advanced composite materials for sustainable structures is beneficial for both parties. The workshop is planned for one day immediately following ?The Fifth Middle East Symposium on Structural Composites for Infrastructure Applications 2008 (MESC-5).? The participants will share findings of their current research projects supported by the National Science Foundation, Departments of Transportation, and the Federal Highway Administration. Each of the ten US participants will submit at least one written contribution on one of the topics covered in the workshop.

Evaluation of a new High Corrosive Resistant Steel Reinforcement for Concrete Structures in the Miditerian Salt Environments The proposed research is a joint program between North Carolina State University, NC, USA, represented by Dr. Sami H. Rizkalla and Ain-shams University, Cairo, Egypt, represented by Dr. Tarek K. Hassan. The prime objective of the proposed research is to investigate the effective use of these innovative, highly corrosion resistance, high strength steel reinforcement for use in highway concrete bridge applications and structures in Egypt . The steel is produced by MMFX Steel Corporation of America and commercially known as ?Micro-composite Multistructural Formable Steel? or ?MMFX Steel?. The proposed testing program will be conducted at the Structural Laboratory at Ain-shams University, Cairo, Egypt. The MMFX rebars will donated by MMFX Coporation . The analytical component will include numerical simulation using cracked section analysis to determine the influence of several parameters, which are known to affect the design requirements for reinforced concrete structures. The effect of the various limitations on the flexural strength and ductility of concrete members reinforced with MMFX will be considered. Based on the research findings, design recommendations for the use of MMFX as main flexural reinforcement for concrete structures will be provided. The research team has demonstrated expertise in the areas of design, development, code writing, testing of highway structures and strategic planning. Dr. Rizkalla and Dr. Hassan have co-authored over 30 technical papers and seven technical reports since 1998. With the expertise of the research team and the full-co-operational between both institutions, the anticipated results of this project will be comprehensive and authoritative documents for flexural design provisions for MMFX rebars will be provided.

The testing program is intended to evaluate the structural performance, mechanical properties, and environmental durability of the V-Wrap High Strength Carbon Fiber Strengthening System. The testing program is designed according to the requirements of the ICC Evaluation Service (ICC-ES) Acceptance Criteria for Concrete and Reinforced and Unreinforced Masonry Strengthening Using Externally Bonded Fiber-Reinforced Polymer (FRP) Composite Systems (AC125). Several full-scale beams and slab specimens will be tested using simple supports configuration to induce flexural or shear failure modes. Variables considered include mode of failure, concrete strength, steel reinforcement, and FRP reinforcement.

The high-strength steel commercially known as Micro-composite Multi-structural formable (MMFX) steel could lead to potential savings through the use of lower reinforcement ratios due to it?s higher strength. However, a critical evaluation of the bond characteristics of MMFX steel with concrete is of paramount importance, especially if high strength is to be utilized. The proposed research will deeply investigate the bond behavior of MMFX steel to concrete. The first phase of the proposed research program will include the parameters believed to significantly affect the bond strength: concrete compressive strength, bar size, concrete clear cover, and confinement level. Three universities are participating in this study, namely, University of Texas at Austin, The University of Kansas, and North Carolina State University. Each university will test twenty-two full-scale splice beams for the first phase of the program.

Strengthening Steel Bridges and Structures Using High Modulus CFRP Materials The research group was successful in selecting the most appropriate resin compatible and suitable for the wet lay-up process using high modulus unidirectional carbon fiber sheets. The research included twenty-two different trials and considered the effect of different cure temperatures, use of a wetting agent, and resin hybridization.The experimental program was extended to determine the development length required to utilize the full strength of the unidirectional carbon fiber sheets and the CFRP material produced in laminate strips. The results of the first two investigations were used in the design of three large scale steel monopoles tested using high modulus unidirectional carbon fiber sheets, CFRP laminate strips, and intermediate modulus CFRP laminate strips. Test results showed substantial increase in the stiffness of the monopoles, up to 39 percent. In response to the demand of the transportation department to increase the carrying capacity of bridges, the CFRP material was used to strengthen large-scale steel/concrete composite girders. Three different strengthening systems considered were the bonding of the intermediate modulus CFRP laminate strip for the first girder, bonding the high modulus CFRP laminate strip for the second girder, and the third girder will make use also of the high modulus CFRP laminate strip, however, using one prestressed ply to improve the initial stiffness of the girder. The first test showed a stiffness increase of 12 percent and up to 42 percent strength increase before rupture of the fibers. The principal investigator succeeded to convince the North Carolina Department of Transportation to include high modulus carbon fiber as one of the materials used to strengthen 40 year old prototype prestressed girders in static testing. The advantage of using this high modulus fiber material could be beneficial to enhance deflection performance under service load conditions. Future Work Brief descriptions of the work planned for the coming two years are: 1. Establish analytical models to simulate the behavior of the measured data for both the steel monopoles and the composite steel/concrete girders. These models will be used to investigate the various parameters that could greatly influence the behavior and provide detailed information useful for future design guidelines. 2. Address durability of the strengthening system by examining its behavior under the effect of different moisture and temperature conditions. The effectiveness of the system under different environmental conditions establishes confidence for the construction industry and for future field application test with NCDOT. 3. Examine the behavior of the strengthening system under the effect of fatigue loading. It is extremely important to study fatigue behavior because the loading simulates actual field conditions. Both the monopoles and the composite steel/concrete girders are proposed for testing. 4. Based on the experimental results and the analytical model, it is proposed to provide detailed design guidelines for steel bridges for the construction industry. 5. Study specific aspects of strengthening steel structures, such as shear lag between the steel surface and the CFRP laminate strips. This phenomenon is not observed in strengthening of concrete structures since the failure typically occurs within the concrete surface. In steel structures, failure most likely occurs through the adhesive layer and shear lag could significantly affect the behavior. 6. Work with NCDOT to select field application and monitor at least one steel bridge. The effort will extend to include other field applications with the private industry. 7. Provide repair kit for bridges that will include construction specifications The above plan may be altered according to findings of the research and market needs.

Based on the approval of the industrial members of the Center for Repair of Buildings and Bridges with Composites, the work started to investigate the bond characteristics of MMFX steel bars as flexural reinforcements for concrete beams. The company requested additional work to investigate the shear behavior of MMFX steel bars for reinforced concrete beams. The work will include building nine concrete beams reinforced with MMFX steel.

The objective of this research is to develop recommended revisions to the AASHTO LRFD Bridge Design Specifications to extend the applicability of the flexural and compression design provisions to concrete up to 18 ksi. The research results will allow full utilization of the material characteristics and greater use of high-strength concrete, since the current LRFD limits the design strength of the ultimate compressive strength of concrete to 69 MPa (10 ksi). The results will have great economical advantages by allowing bridge design engineers to design AASHTO girders more effectively in terms of the thickness of the web and larger beam spacing.

This proposal is developed in response to Research Idea ST-04 in the NCDOT FY-2006 List of Research Ideas. The proposed research program is an extension of NCDOT Project 2004-15: Value Engineering and Cost-Effectiveness of Various FRP Repair Systems. NCDOT Project 2004-15 will be completed June 30, 2005 and included testing of seventeen 30 ft long prestressed concrete C-Channels under static and fatigue loading conditions using various CFRP strengthening systems to determine structural behavior, constructability of the various systems and cost-effectiveness. One 54 ft long impact damaged AASHTO girder will also be repaired before completion of the project to regain its original flexural capacity using a CFRP system and tested under fatigue loading conditions. The proposed project extension will include the following tasks: 1) test three impact damaged 54 ft long AASHTO girders repaired to original strength using CFRP sheets under fatigue loading conditions, and 2) test two 30 ft long prestressed concrete C-Channels strengthened using an innovative high strength steel wire mesh strengthening system and tested under static and fatigue loading conditions. Results of Project 2004-15 and the proposed extension will be used to produce complete design guidelines. The project will provide bridge maintenance engineers with a comprehensive document to select the most appropriate repair or strengthening systems along with the cost-effectiveness and value engineering for each system. The duration of the proposed extension is one year.

Bond Characteristics and Qualifications of Adhesives for Marine Applications and Steel Pipe Repair This project investigates the bond properties and shear behavior of two different adhesives used for marine structures and repair of steel pipes. The experimental program consists of four phases including single lap shear testing, environmental exposure testing, cleavage peel testing, and creep testing. The first phase of the experimental program was completed. Currently, work is being performed in the second phase of the investigation. The first phase is comprised of testing specimens composed of GFRP sheets bonded together as well as specimens composed of GFRP sheets bonded to steel sheets. A total of ten GFRP-to-GFRP lap shear specimens bonded using the two specified adhesives were tested. Testing procedures for the GFRP-to-steel specimens were identical to that of the GFRP-to-GFRP specimens. The main objective of the second phase of the experimental program is to determine the influence of different environmental conditions on the bond characteristics of adhesives. Different environmental conditions include temperature, pH level, and underwater curing. A total of 27 specimens have been tested. The temperature level is set to either 120oF or 140oF, and the pH level is at 4, 7, or 9.5. The specimens were submerged in de-ionized water having a given temperature and a pH value and loaded in tension to induce shear stresses in the test sample gage section. The specimens are subjected to constant load levels of either 200, 600 or 800 lbs . The time that it takes for the specimen to fail under those conditions is recorded. Future Work Currently, progress is continuing on the environmental exposure tests. More specimens will be tested under various pH levels, loads, and temperatures, according to the original test matrix. The research will be extended within the next two years to study the temperature variation and its effect on the adhesives? performance by testing control specimens under room temperature. The third and fourth phases of the experimental program will begin after completion of the second phase. The cleavage peel tests for composite-composite and steel-composite specimens will be conducted according to ASTM 3807. The testing will be performed at room temperature. The fourth and final phase of the experimental program will consist of lap shear specimens loaded to 400, 600 and 1000 psi for creep testing.

Deteriorating condition of concrete bridges and other infrastructure facilities has been documented by several researchers and recognized by highway agencies as one of the most serious problems facing the civil engineering infrastructure worldwide. In the last decade, innovative structural materials including composites and highly corrosive resistant steel reinforcement have set ambitious goals in the vast civil infrastructure market. The primary objective of this proposal is to request a travel support for five American experts in the field of FRP and new construction materials to contribute as key note speakers in the international conference on future vision and challenges for urban development at Cairo, Egypt in December 2004. The participants will share findings of their current research projects supported by the National Science Foundation, Departments of Transporation, Federal Highway Adminstration, and National Cooperative Highway Research Program. Each of the five participants from the United States will submit at least one written contribution on one of the topics covered in the conference. These contributions will be presented and published in the conference proceedings, which will be available to all participants prior to the conference. Experts from the United States, Canada, Europe and Japan will also be invited to participate in the conference. The conference proceedings will be prepared and published by the conference organizing committee. The proceedings will be widely distributed in the United States to research institutions and universities. The presentations will be available at various professional meetings, conferences and journals.