Abdul-Hamid Zureick

Creep Behavior of Fiber-Reinforced Polymeric Composites: A Review of the Technical Literature:

This report provides a review of the technical literature related to the creep behavior of fiber reinforced polymer (FRP) composites. The review presented here was directed toward those papers that define the direction and line of thinking in the area of experimental techniques that may be candidates for the development of accelerated test methods to predict the long-term performance of FRP composite materials for highway structural applications. Linear and nonlinear viscoelastic theories as they relate to the modeling and prediction of the viscoelastic response of FRP materials under constant loads are included. Accelerated characterization techniques for the viscoelastic behavior of FRP composites including the use of elevated temperatures and frequency domain loading are reviewed. The effects of moisture and temperature on the creep behavior of composites are briefly considered. The interaction between creep behavior and fatigue behavior is also included in the discussion.

Repair and strengthening of reinforced concrete beam-column joints: State of the art

The latest report by Joint ACI-ASCE Committee 352 (ACI 352R-02) states that joints in structures built before the development of current design guidelines need to be studied in detail to establish their adequacy and that methods of connection repair and strengthening need to be developed. Prior to developing new strengthening schemes, it is important that the findings from research previously conducted on other strengthening techniques be known. This paper presents a comprehensive up-to-date literature search pertaining to the performance of as well as to the repair and strengthening techniques for, nonseismically designed reinforced concrete beam-column joints, reported between 1975 and 2003. These techniques included: 1) epoxy repair; 2) removal and replacement; 3) concrete jacketing; 4) concrete masonry unit jacketing; 5) steel jacketing and addition of external steel elements; and 6) strengthening with fiber-reinforced polymeric (FRP) composite applications. Each method of repair or strengthening is reviewed with emphasis on its application details, required labor, range of applicability, and performance. Relative advantages and disadvantages of each method are discussed.

Properties of fibre reinforced concrete using recycled fibres from carpet industrial waste

A study was carried out to evaluate the use of recycled fibres from carpet industrial waste for reinforcement of concrete at 1 and 2 vol% fractions. Compressive, flexural, splitting tensile and shrinkage tests were performed. Significant increases in shatter resistance, energy absorption and ductility were observed. This paper reports on the experimental programme and compares the effectiveness of such recycled fibres with that of virgin polypropylene fibres specially made for fibre reinforced concrete (FRC). The paper also discusses the benefits of using such FRC for construction applications and possible ways to further enhance the performance of such FRC.

Three-parameter vs. two-parameter Weibull distribution for pultruded composite material properties

The three-parameter and two-parameter Weibull distributions are compared using 26 mechanical property data sets of fiber-reinforced polymeric (FRP) composite materials manufactured by the pultrusion process. Both strength and stiffness properties were examined. The probability distributions were compared on the basis of goodness of fit, nominal design values, and allowable load to achieve uniform reliability. It is recommended that the two-parameter Weibull distribution be used to characterize FRP composite material properties. The primary basis for this recommendation is small differences in nominal design values and small differences in allowable loads between the two-parameter and three-parameter Weibull distributions. Other supporting reasons for the recommendation are similar observed significance levels in distribution fitting, computational efficiency, and the fact that the location parameter of the three-parameter Weibull distribution is near the first order statistic.

Compression creep of a pultruded E-glass/vinylester composite

This paper presents the results of an experimental investigation pertaining to the long-term behavior of pultruded fiber-reinforced polymeric materials subjected to longitudinal compressive loading. Material coupons cut from a pultruded vinylester/E-glass I-shape section were subjected to axial compressive loads at various stress levels for time durations up to 10 000 h. The strain measurements over time were recorded and compared to a practical power law formulation, with good agreement. A predictor design equation for the time-dependent longitudinal modulus was developed on the basis of the experimental results.

Characterization of the longitudinal tensile behavior of pultruded I-shape structural members using coupon specimens

Abstract Durable, lightweight, and low cost pultruded structural composites are suitable materials for construction applications. An experimental program has been carried out to characterize the tensile behavior of pultruded composite I-shape structural members using coupon specimens of different widths cut from different locations. Results of material strength, modulus, and failure mechanisms are reported. It was observed that the specimen width and original location had significant effects on the variation of the test data. However the average strength and modulus values were not significantly affected by these factors. Recommended methods for specimen selection and for estimation of material property data for structural design are discussed.

Reliability-Based Evaluation of Flexural Members Strengthened with Externally Bonded Fiber-Reinforced Polymer Composites

Structural applications of carbon fiber-reinforced polymer (FRP) composites in civil infrastructure rehabilitation projects are receiving increasing interest due primarily to their high strength-weight ratio, resistance to aggressive environments, and other favorable properties that can be used to advantage in civil projects. Structural design and evaluation in civil engineering applications are distinguished by their reliance on codes of practice and on advanced analysis in lieu of component testing. The current lack of supporting codes, standards, and other regulatory guidance is a barrier to the implementation of high-performance FRP materials in civil construction. Experience over the past three decades in developing probability-based limit state design criteria for common construction materials points the way forward for making similar advances in guidelines for design and evaluation of structural components and systems that employ FRP composite materials. This paper summarizes some of the available tools and supporting databases that can be used to develop reliability-based guidelines for design and evaluation of FRP composites in civil construction and illustrates their application with several practical examples involving strengthening reinforced concrete flexural members.

Curved steel I-girder bridges: experimental and analytical studies

This paper describes the large-scale experimental and analytical program, initiated by the Federal Highway Administration (FHWA), aimed at developing new rational design guidelines for horizontally curved steel bridges. Analytical and experimental efforts dedicated to establish the size of the full-scale components that will be tested as part of an entire three-girder bridge system are also presented.

Bridge Rating Using System Reliability Assessment. I: Assessment and Verification by Load Testing

Condition assessment and safety verification of existing bridges and decisions as to whether a bridge requires posting currently are addressed through analysis, load testing, or a combination of these methods. The rating process is described in AASHTO’s Manual for Bridge Evaluation, which permits ratings to be determined by allowable stress, load factor, or load and resistance factor methods, the latter of which is keyed to AASHTO LRFD Bridge Design Specifications. These three rating methods may lead to differently rated capacities and posting limits for the same bridge, a situation that has serious implications with regard to public safety and the economic well-being of communities that may be affected by bridge postings or closures. This paper is the first of two papers that summarize a research program to develop improvements to the current bridge rating process using structural reliability methods. This paper appraises current bridge rating methods and summarizes a coordinated program of analysis and ...

Local buckling of fiber-reinforced polymeric structural members under linearly-varying edge loading — Part 1. Theoretical formulation

This paper presents a general solution to the problem of local buckling of doubly symmetric fiber-reinforced polymeric structural shapes subjected to linearly-varying edge loading. This solution is based upon the classical theory of orthotropic plates and accounts for the elastic restraint of various plate elements comprising the cross-section. The buckling equations for box and I-shape beams subjected to pure bending in one case and to uniform compression in another case are deduced as special cases from the present solution. Numerical results in the form of design charts are discussed and presented in a companion paper.