Papers by Houssam Toutanji
Lecture notes in civil engineering, 2023
Springer eBooks, Nov 27, 2021
Structural Concrete, Aug 29, 2019
This paper investigates the influence of cyclic preloading on the fatigue behavior of reinforced ... more This paper investigates the influence of cyclic preloading on the fatigue behavior of reinforced concrete (RC) beams rehabilitated with near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) reinforcement. The study includes eight RC beams with dimensions of 152.4 × 152.4 × 1,521 mm. Strengthened and nonstrengthened specimens were tested under monotonic loading to obtain the flexural static capacity. Two strengthened specimens were tested as a reference under constant amplitude cyclic stress without prefatiguing. Four nonrehabilitated RC beams were prefatigued to simulate service loading conditions. Later, these RC beams were rehabilitated with NSM CFRP reinforcement and tested under the same cyclic stress range of the reference specimens. Mid-span deflection, strain of tension steel rebars and CFRP rods, stiffness degradation, and energy dissipation were analyzed and evaluated. Experimental results show that the rehabilitated prefatigued RC beams had similar stiffness degradation and failure modes to the reference strengthened RC beams. The rehabilitated RC beams had an improvement in the fatigue responses when compared to the reference strengthened RC beams. Moreover, the postfatigue monotonic behavior of the rehabilitated RC beams showed an increase in the elastic modulus and a decrease in ductility.
Current design methods for predicting deflections and crack widths at service load in concrete st... more Current design methods for predicting deflections and crack widths at service load in concrete structures reinforced with steel bars may not be necessarily applicable in those reinforced with fiber reinforced polymer (FRP) bars. In this paper, methods for predicting deflections and crack widths and spacing of glass fiber reinforced polymer (GFRP) reinforced concrete beams were proposed. In order to use the effective moment of inertia for concrete beams reinforced with FRP bars, the effect of reinforcement ratios and elastic modulus of the FRP reinforcement were incorporated in Branson's equation. This paper also presents a new equation to predict crack width. Six concrete beams reinforced with different GFRP reinforcement ratios were tested. Deflections and crack widths were measured and compared with those obtained by proposed models. The comparison between the experimental results and those predicted was in good agreement.
Tactical missiles within the US Army are regularly subjected to severe stresses such as long term... more Tactical missiles within the US Army are regularly subjected to severe stresses such as long term exposure in harsh environments and transportation handling. These stresses factor into the ageing, deterioration, and eventual decommissioning of some of the Army's critical warfighting assets. The negative reliability impacts associated with long-term ageing and deterioration significantly affect the total lifecycle cost of fielding these weapons in a high state of readiness. Reliability evaluation of past data has indicated failures in missile structural, energetic, and electronic components associated with the long-term exposure to heat, humidity, and transportation shocks. Unlike strategic missiles, tactical missiles undergo a very minimum of field checks and non-destructive evaluation on a routine basis. The Army Aviation and Missile Research, Development, and Engineering Center have been developing a health monitoring system called Remote Readiness Asset Prognostics and Diagnostics System (RRAPDS) to assess and improve reliability of the missiles during storage and field exposures [1]. RRAPDS will use external and internal sensors to provide data to assess missile conditions and predict reliability. This paper describes the approach to predict reliability of missile components like propellant, nozzles, and thermal batteries using sensor data from RRAPDS, and prognostic models for structural integrity and damage mechanisms. Probabilistic models will quantify all the uncertainties present in the health monitoring data and finite element models, to provide a realistic reliability evaluation. Recently, there has been a significant shift in how the Army builds and fields its missiles. This change has had a major impact on degradation factors affecting Army missiles as well as considerations needed to manage and assess degradation. Prior to Operation Desert Storm, the Army's missiles were designed for long-term storage in depots without extensive deployments. Additionally, these generations of Army missiles were designed and built to a government-owned specification resulting in highly homogeneous configurations.
Civil Engineering, Oct 1, 2008
Advances in weigh-in-motion (WIM) technology over the past 15 years have led to successful field ... more Advances in weigh-in-motion (WIM) technology over the past 15 years have led to successful field application of a commercial grade portable Bridge WIM system (B-WIM) in Europe. Under a previous UTCA Research Project No. 07212, the University Transportation Center for Alabama (UTCA) tested the state-of-the-art commercially available B-WIM technology on two interstate highway bridges. The equipment tested was developed by CESTEL, a Slovenian technology company, and is commercially referred to as the SiWIM system. Some technical difficulties occurred during the Project 07212 field tests; however, the SiWIM system was successfully installed, calibrated, and placed into a data gathering mode at both sites. The objective of the research described in this report was to develop a practical recommendation for installation of SiWIM technology at potentially multiple locations in the State of Alabama for the primary purpose of traffic enforcement. The researchers worked with the Alabama Department of Transportation (ALDOT) to select a bridge for instrumentation that has the potential for an excellent accuracy classification rating. The bridge selected is located on US Highway 78 East in Graysville, Alabama. The bridge structure consists of three 42-ft simply supported reinforced concrete T-beam spans with two traffic lanes in one direction. In addition, an ALDOT-operated Bending Plate Weigh-In-Motion System (BP-WIM) is located approximately four miles to the west also on US Highway 78. After installing the SiWiM system on the bridge, calibration and three in-service simulated enforcement test exercises were conducted. Over one hundred trucks were weighed by the SiWIM system and compared to their static weights. Many of the trucks were also weighed by the BP-WIM system. The accuracy classification established for the SiWIM system during the calibration and subsequent in-service tests varied between ±20% and ±44% of the static weight with a confidence level of 85%. This level of accuracy is not precise enough to be used with confidence to screen trucks for weight enforcement. The additional BP-WIM data collected during this program indicated that the SiWIM system may be as accurate as the nearby BP-WIM system tested. Lessons learned from the work reported here have been of benefit. In March, 2011, ALDOT personnel installed, calibrated, and operated a newer model of the SiWIM system on a shorter span bridge, achieving B(10), C(15), AND B(10) accuracy classification in random truck weighing for gross vehicle weight, group axles, and single axles, respectively.
Lecture Notes in Civil Engineering
This project developed a Load and Resistance Factor Design (LRFD) multimedia package to provide a... more This project developed a Load and Resistance Factor Design (LRFD) multimedia package to provide a practical introduction and an in-depth understanding of the new technological advances in the design of steel bridges. This package can be used to train engineers, architects, designers, and personnel who are in charge of the design, construction, maintenance, and rehabilitation of bridges. The complete package includes instructions of how to design a steel bridge with AASHTO load and resistance factor design recommendations and specifications. The package includes five practical examples to provide a generic overview of the design concept and process.
La resistance a la traction directe de la pate de ciment - fumee de silice et de mortier a ete ev... more La resistance a la traction directe de la pate de ciment - fumee de silice et de mortier a ete evaluee pour differents rapports eau/ciment. Quatre rapports eau/ciment ont ete utilises, 0,22, 0,25, 0,28, 0,31, avec un dosage de fumee de silice en pourcentage de ciment de 8%, 16% et 25%. Pour chaque formulation, le dosage du superplastifiant a ete ajuste afin d'eviter la segregation. Les resultats ont montre qu'un remplacement partiel de ciment de 8% de fumee de silice engendre une augmentation de la resistance a la traction du mortier, mais aucun effet sur la resistance a la traction de la pate de ciment. Le remplacement de ciment par un important dosage de fumee de silice (16% et 25%) entraine une diminution de la resistance a la traction du mortier ainsi que de la pate de ciment. Cette diminution a ete plus importante dans le cas de ciment que dans celui du mortier. Il est aussi demontre que l'utilisation du superplastifiant avec fumee de silice joue un role plus effica...
Copyright © 2006, American Concrete Institute. All rights reserved including rights of reproducti... more Copyright © 2006, American Concrete Institute. All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.
A novel technique for evaluating the tensile strength of FRP tow sheets and cement-based specimen... more A novel technique for evaluating the tensile strength of FRP tow sheets and cement-based specimens wrapped with FRP tow sheet composites is introduced. The ASCERA hydraulic tensile tester is used for determining the tensile strength which is derived from the hydraulic pressure and sample geometry. The tensile strength of the carbon fiber wrapped cement composites were in the range of 78 to 132 MPa. The glass fiber composites were in the range of 40 to 55 MPa, while the unwrapped cement specimens were under 7 MPa. The results show a significant difference in tensile strength properties with the application of epoxy-resin system. The tensile strength values are presented using Weibull statistics. A model using the rule of mixtures is used to predict the tensile strength of the FRP composites. Fractography is used to locate the failure initiating defects and to identify the failure modes associated with the different composite wrap systems.
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Papers by Houssam Toutanji