Tarek K. Hassan

Bio: Tarek K. Hassan is an academic researcher from Ain Shams University. The author has contributed to research in topics: Prestressed concrete & Precast concrete. The author has an hindex of 12, co-authored 27 publications receiving 1004 citations. Previous affiliations of Tarek K. Hassan include North Carolina State University & University of Manitoba.

Investigation of bond in concrete structures strengthened with near surface mounted carbon fiber reinforced polymer strips

Abstract: Fiber reinforced polymer (FRP) materials are currently produced in different configurations and are widely used for the strengthening and retrofitting of concrete structures and bridges. Recently, considerable research has been directed to characterize the use of FRP bars and strips as near surface mounted reinforcement, primarily for strengthening applications. Nevertheless, in-depth understanding of the bond mechanism is still a challenging issue. This paper presents both experimental and analytical investigations undertaken to evaluate bond characteristics of near surface mounted carbon FRP (CFRP) strips. A total of nine concrete beams, strengthened with near surface mounted CFRP strips were constructed and tested under monotonic static loading. Different embedment lengths were used to evaluate the development length needed for effective use of near surface mounted CFRP strips. A closed-form analytical solution is proposed to predict the interfacial shear stresses. The model is validated by comparing t...

Bond Mechanism of Near-Surface-MountedFiber-Reinforced Polymer Bars for FlexuralStrengthening of Concrete Structures

Abstract: This paper presents both experimental and analytical investigations undertaken to evaluate bond characteristics of near-sutfacemounted (NSM) carbon fiber-reinforced polymer (CFRP) bars. A total of eight concrete beams. strengthened with NSM CFRP bars, were tested under monotonic static loading. Different embedment lengths are studied to determine the development length of the fiber-reinforced polymer (FRP) reinforcement. The performance of two different adhesives used to bond the bars to the surrounding concrete is examined. A general methodology to evaluate the development length of NSM FRP bars of different configurations and types of fibers is presented. A quantitative criterion governing debonding failure is established. The proposed bond model assumes linear elastic behavior jar the concrete, adhesive, and the NSM FRP bars, following the same philosophy oj the ACI provisions for bond analysis and design. The proposed analytical model is validated by comparing the predicted values with test results as well as to nonlinear finite element modelling. The influence of key parameters, including the thickness of the adhesive cover, groove width, groove spacing, and inte171ai steel reinforcement configuration, are discussed.

Design recommendations for the use of FRP for reinforcement and strengthening of concrete structures

Abstract: The use of fibre reinforced polymer, FRP, as reinforcement for concrete structures has been growing rapidly in recent years. This paper summarizes the current state of knowledge of these materials and highlights the various FRP strengthening techniques that have been used for concrete and masonry structures. Material characteristics of FRP and fundamental design considerations are discussed. Selection of the appropriate materials and their corresponding advantages and disadvantages are highlighted. Design philosophies for concrete members reinforced and/or strengthened with FRP are enumerated. Fundamental flexure, shear and bond behaviour of concrete members reinforced and/or strengthened with FRP according to the current ACI design guidelines are examined. The paper also reviews the durability aspects of FRP and describes selected field applications of these materials. Copyright © 2003 John Wiley & Sons, Ltd.

Behavior of precast, prestressed concrete sandwich wall panels reinforced with CFRP shear grid

Abstract: This paper describes the structural behavior of precast, prestressed concrete sandwich wall panels reinforced with carbon-fiber-reinforced polymer (CFRP) shear grid to achieve composite action. Use of CFRP as a shear transfer mechanism was intended to increase the thermal insulation efficiency, enhance the service life, and increase the overall structural capacities of the panels. This study included testing of six full-scale sandwich wall panels, each measuring 20 ft x 12 ft (6.1 m x 3.7 m). The panels consisted of two outer prestressed concrete wythes and an inner insulation wythe. The study included two types of insulation and several shear transfer mechanisms with different CFRP reinforcement ratios to examine the degree of composite action developed between the two concrete wythes. All panels were simultaneously subjected to applied gravity and lateral loads. Reverse-cyclic lateral loads simulated the effects of wind pressure and suction. All panels were subjected to approximately 4000 cycles of lateral loading with the presence of factored gravity load. Following each fatigue regime, the lateral loads were increased until failure was achieved. Test results of the experimental program were compared with theoretical predictions of fully composite and noncomposite actions to evaluate the percent composite action and to assess the optimum panel configuration.

Flexural strengthening of prestressed bridge slabs with frp systems

Abstract: Fiber reinforced polymer (FRP) materials offer great potential for cost effective retrofitting of concrete structures. In response for the growing need for strengthening and rehabilitation of concrete structures and bridges, an experimental program was conducted to investigate the feasibility of using different strengthening techniques as well as different types of FRP for strengthening prestressed concrete members. Half scale models of a prestressed concrete bridge were constructed and tested to failure. The test specimens consisted of one simple span and two overhanging cantilevers. Each specimen was tested three times using a different load location in each case. The applicability of a nonlinear finite element analysis of post-tensioned bridge slabs strengthened with near surface mounted FRP reinforcement is enumerated.

Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures

Abstract: *Co-chairs of the subcommittee that prepared this document. Note: The committee acknowledges the contribution of associate member Paul Kelley. ACI encourages the development and appropriate use of new and emerging technologies through the publication of the Emerging Technology Series. This series presents information and recommendations based on available test data, technical reports, limited experience with field applications, and the opinions of committee members. The presented information and recommendations, and their basis, may be less fully developed and tested than those for more mature technologies. This report identifies areas in which information is believed to be less fully developed, and describes research needs. The professional using this document should understand the limitations of this document and exercise judgment as to the appropriate application of this emerging technology.

Near-surface mounted FRP reinforcement: An emerging technique for strengthening structures

Abstract: Near-surface mounted (NSM) fiber-reinforced polymer (FRP) reinforcement is one of the latest and most promising strengthening techniques for reinforced concrete (RC) structures. Research on this topic started only a few years ago but has by now attracted worldwide attention. Issues raised by the use of NSM FRP reinforcement include the optimization of construction details, models for the bond behaviour between NSM FRP and concrete, reliable design methods for flexural and shear strengthening, and the maximization of the advantages of this technique. This paper provides a critical review of existing research in this area, identifies gaps of knowledge, and outlines directions for further research.

Investigation of bond in concrete structures strengthened with near surface mounted carbon fiber reinforced polymer strips

Abstract: Fiber reinforced polymer (FRP) materials are currently produced in different configurations and are widely used for the strengthening and retrofitting of concrete structures and bridges. Recently, considerable research has been directed to characterize the use of FRP bars and strips as near surface mounted reinforcement, primarily for strengthening applications. Nevertheless, in-depth understanding of the bond mechanism is still a challenging issue. This paper presents both experimental and analytical investigations undertaken to evaluate bond characteristics of near surface mounted carbon FRP (CFRP) strips. A total of nine concrete beams, strengthened with near surface mounted CFRP strips were constructed and tested under monotonic static loading. Different embedment lengths were used to evaluate the development length needed for effective use of near surface mounted CFRP strips. A closed-form analytical solution is proposed to predict the interfacial shear stresses. The model is validated by comparing t...