M. Maalej

M. Maalej
University of Sharjah | US · Department of Civil and Environmental Engineering

Ph.D., University of Michigan

About

95
Publications
24,974
Reads
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3,933
Citations
Additional affiliations
August 1999 - June 2006
National University of Singapore
Education
August 1991 - April 1994
University of Michigan
Field of study
  • Civil Engineering

Publications

Publications (95)
Article
Due to the inherent uncertainties in the properties of construction materials, fabrication processes, applied loads, and the approximate nature of analysis methods, modern design codes have adopted the Load and Resistance Factor Design format (LRFD) to design civil engineering structures. In this format, loads and resistance are factored to conside...
Article
Modern design codes apply the Load and Resistance Factor Design (LRFD) format to account for all uncertainties involved, primarily manufacturing, fabrication, and modeling errors. In this format, load effects are scaled-up by load factors while a resistance factor scales down the resistance. In this way, the LRFD design format ensures that all desi...
Chapter
This paper is part of an ongoing research project on punching shear strength of reinforced concrete flat slabs incorporating macro synthetic fibers. Results obtained from testing six slabs (1500 × 1500 × 150 mm) are reported and discussed in this paper. The slabs were reinforced with flexural reinforcement ratio of 0.9% and macro synthetic fibers w...
Article
Unreinforced Masonry (URM) walls are construction elements that have been found to resist in-plane forces, which proved beneficial for wind and earthquake resistant design. The out-of-plane resistance of URM walls, however, is very minimal, if any. Strengthening the walls in the out-of-plane direction is an ongoing research topic. This study aims a...
Article
Externally strengthening reinforced concrete (RC) structures has been a desired practice in both research community and the industry over the last few decades. This application entails bonding composites to the surfaces of RC members to upgrade their strength, stiffness, and ductility. This study will attempt to use Machine Learning (ML) techniques...
Conference Paper
The aim and objective of this research project was to develop and investigate a rapid method of strengthening the Unreinforced Masonry walls (URM) for out-of-plane action. A total of 12 URM walls, built inside a precast fiber reinforced concrete boundary frame, were strengthened with a cement-based concrete mix with or without steel reinforcement....
Article
This paper presents an investigation of the performance of RC beams incorporating macro-synthetic fibers and rehabilitated using Externally Bonded Fiber Reinforced Polymer (EB-FRP) strips. A series of tests were conducted to investigate the EB-FRP contribution to the shear strength recovery of pre-damaged shear-deficient beams. The investigation in...
Article
Full-text available
Discrete macro fibers such as steel and synthetic have been recognized as an attractive material to improve concrete properties such as flexural toughness, shear strength, impact characteristics, deflection capacity and concrete ductility. In this paper, the effect of macro synthetic fibers on punching shear resistance and cracking behavior of rein...
Article
Full-text available
This paper aims at investigating the effect of S-wrap EB-CFRP to shear-strengthen RC T-beams. The experimental program included seven 3.3m-span T-beams that were tested under three-point loading. The specimens were divided into two major groups, including four specimens with no steel stirrups (Group 1), and three specimens with steel stirrups at ha...
Conference Paper
Full-text available
This research study is conducted to investigate the flexural behaviour of steel fiber reinforced concrete (SFRC) prisms incorporating different types and volume fractions of steel fibers, various grades of concrete, and different specimen depths, all tested under displacement control mode using four-point loading configuration. Two types of steel f...
Article
Full-text available
This paper presents results from an ongoing research that is intended to study the behavior of URM walls for out-of-plane action. The effect of fiber reinforced shotcrete (FRS) as a strengthening method for the URM walls is examined. Eight URM walls were built inside a precast reinforced concrete boundary frame and strengthened with cement-based sh...
Article
This paper presents the results of an experimental investigation on the behavior of Reinforced Concrete (RC) beams repaired and strengthened using Externally Bonded Carbon Fiber Reinforced Polymer (EB-CFRP). The experimental program involved 19 static tests on 16 simply supported rectangular RC beams in which seven were tested without CFRP and 12 w...
Article
This paper presents a comprehensive analysis of mathematical models for estimating the shear strength of trapezoidal-corrugated steel webs. The existing database of experimental data on trapezoidal corrugated steel web beams and girders is updated by adding more test results, yielding a total of 144 tests. The three-parameter model, previously deve...
Conference Paper
Full-text available
Unreinforced masonry (URM) elements are mainly designed to withstand in-plane compression loads with little or no consideration of the forces generated in the event of an earthquake or impact loads. In the occurrence of such events, the URM elements experience in-plane and/or out-of-plane lateral loads, which they are not designed for, and thus, th...
Conference Paper
This paper is part of an on-going research project on the behavior of damaged Reinforced Concrete (RC) beams repaired and strengthened with Externally Bonded Fiber Reinforced Polymer (EB-FRP). A total of seven full-scale rectangular beams; fully-damaged in a previous study, were repaired and retested to failure. The repair methodology consists of f...
Article
This paper reports the results of an experimental investigation of the shear behavior of beams made using hybrid fiber–engineered cementitious composites (HFECC). The paper specifically deals with the shear behavior of beams made using strain hardening engineered cementitious composites that incorporate relatively low volume ratios (Vf≤2%) of disco...
Article
Steel corrugated webs are vertical and lightweight plates responsible for carrying large in-plane loads before buckling. Three modes of shear failure are typical for these elements: local, global, and interactive shear buckling. In this paper, previously published analytical models for the estimation of the shear strength of trapezoidal corrugated...
Conference Paper
Full-text available
This research paper is part of an ongoing research on the behaviour of Reinforced Concrete (RC) beams retrofitted with Externally Bonded Carbon Fiber Reinforced Polymer (EB-CFRP). A total of 5 large-scale rectangular beams, previously damaged due to shear loading, were repaired and strengthened with EB-CFRP and tested in this study. The major crack...
Article
Full-text available
This paper reports the results of an experimental program on the effectiveness of ductile fibre reinforced cementitious composites (DFRCC) in retarding the corrosion of steel, corrosion induced damage and post-corrosion structural behaviour of reinforced concrete (RC) columns. Two series RC columns are included in this program. The first series con...
Article
Full-text available
This paper reports the results of an experimental program involving several small-scale columns which were constructed to simulate corrosion damage in the field using two accelerated corrosion techniques namely, constant voltage and constant current. A total of six columns were cast for this experiment. For one pair of regular RC columns, corrosion...
Article
This study aims to evaluate the feasibility of using ultra-ductile Engineered Cementitous Composites (ECC) as a means to enhance the performance of beam–column connections. Nine one-third scale specimens, consisting of type 2 (ACI352R-02) interior connections at a zone of high seismicity (UBC-zone 3), were tested under reverse cyclic loading, simul...
Article
This paper reports the development of ductile fibre reinforced geopolymer composites (DFRGC) where the cement binder is replaced by fly ash based geopolymer binder. In this study, three types of fibres are considered namely steel and two types of polyvinyl alcohol (PVA) fibres having different diameters, lengths and elastic modulus. The fibres are...
Article
This paper reviews some of the recent research work focusing on assessing the performance of hybrid fiber Engineered Cementitious Composite (ECC) materials in a number of potential structural applications. A summary of the design and characteristics of such materials is presented followed by a review of recent potential applications of hybrid fiber...
Article
This paper reviews the results of recent laboratory research studies focusing on the behavior of hybrid fiber Engineered Cementitious Composite (ECC) panels subjected to low- and high-velocity projectile impact. The reviewed laboratory studies include high-velocity (300-700. m/s) small-size projectiles impact tests conducted on 0.30. . 0.17. m hybr...
Article
This paper reviews some of the recent progress in the structural applica-tions of hybrid fiber Engineered Cementitious Composite (ECC) materials. A summary of the design and characteristics of such materials is presented followed by a review of recent applications of hybrid fiber ECC. The reviewed applications include the use of hybrid fiber ECC fo...
Article
This paper presents the results of a study on the quasi-static and dynamic uni-axial tensile behaviours of polyethylene-fibrous ferrocement. The study first focused on the quasi-static tensile responses of fibrous-ferrocement reinforced with different volume fractions of short polyethylene fibres. The dynamic tensile behaviour was next investigated...
Article
In this paper, a total of 18 masonry wall panels were tested under both quasi-static and dynamic loadings to assess the extent to which a cementitious-based material known as Engineered Cementitious Composite (ECC) can enhance the out-of-plane resistance of unreinforced masonry (URM) walls. The masonry wall panels, which were retrofitted with an ul...
Article
A functionally-graded (FG)-cementitious panel consisting of PE-fibrous ferrocement, calcined bauxite aggregates and conventional mortar was developed to resist high-velocity small projectile penetration. A total of 72 specimens measuring 200 mm by 200 mm by 100 mm were fabricated and subjected to ogive-nosed (Caliber Radius Head, CRH = 2.5) project...
Article
This paper presents a three-dimensional finite element model for functionally-graded (FG) cementitious panel subjected to high-velocity small projectile impact using the commercial package, LS-DYNA. The FG-panel consists of PE-fibrous ferrocement as the top and bottom layers, sandwiching a thin layer of concrete with calcined bauxite aggregates and...
Article
This paper presents a laboratory investigation to study the effect of cracking, corrosion and repair on the frequency response of simply-supported reinforced concrete beams. The beams were subjected to four-point bending at 70% of their theoretical ultimate loads. Corrosion was then induced using an electro-chemical acceleration technique. The beam...
Article
In this article, the experimental results of hybrid-fiber engineered cementitious composite (HFECC)-strengthened masonry walls subjected to quasi-static out-of-plane loadings are reported. The aim is to assess the extent to which HFECC-strengthening systems can improve the out-of-plane resistance of unreinforced masonry walls. A total of 12 masonry...
Article
This paper presents a numerical study of a Functionally-Graded (FG) cementitious panel subjected to high-velocity small-projectile impact with striking velocity ranging from 300 m/s to 600 m/s. This FG panel comprised three different materials, namely PE-fibrous ferrocement, calcium bauxite aggregate concrete and conventional mortar, layered at dif...
Article
Tensile strain hardening and multiple cracking behaviours of fibre reinforced cementitious composites containing different hybrid combinations of steel (ST) and polyethylene (PE) fibres are reported. Various hybrid combinations of ST and PE fibres of 12 mm length are studied. Different hybrid combinations of ST and PE fibres of 18 mm length are als...
Article
This paper summarises an effort in the development of a remote flood monitoring system based on plastic optical fibre (POF) sensors and a wireless mote network. The wireless mote, comprising of a network of MICA2DOT™ units, was used as a platform to monitor and record the signal from the POF sensors and transmit this information to a base station w...
Article
An innovative Hilbert–Huang transform (HHT) based frequency identification approach designated as adaptive magnitude spectrum algorithm (AMSA) is proposed in this paper. Characterized by the a posteriori property, the AMSA does not need the a priori information about the modal frequencies to be identified, and the situations that a modal frequency...
Article
Full-text available
An electrochemical-based accelerated corrosion technique has been employed to study the corrosion durability of ferrocement. Variables considered include cover thickness; composition of the matrix in terms of water-cement ratio (w/c), sand-cement ratio (s/c), and contents of mineral and chemical admixtures; and use of stainless steel wire mesh. Aft...
Article
This paper presents the results of an experimental study to evaluate the damage and failure mode of hybrid-fiber engineered cementitious composite (ECC) panels caused by large projectiles or fragments. The aim is to quantify the extent to which hybrid-fiber ECC improves the resistance of blast panels against impact loading. Drop weight tests were c...
Article
An analytical model for the design of strain-hardening and multiple-cracking behavior of engineered cementitious composites (ECC) containing hybrid fibers is proposed. The model predicts first crack strength and ultimate bridging strength of hybrid fiber ECC. The model also predicts the minimum (critical) volume fraction of fibers required to exhib...
Article
Strain hardening and multiple cracking behavior of hybrid fiber reinforced cement composites containing different hybrid combinations of steel and polyethylene (PE) fibers under four-point bending are reported. The total volume fraction of fibers was kept constant at 2.5% to maintain a workable mix. Effects of increase in fly ash content as partial...
Article
A finite element (FE) model is proposed to simulate the corrosion-induced cracking of reinforced concrete (RC) beams. The smeared cracking approach is used to model the cracking of ordinary concrete, ductile fiber-reinforced cementitious composites (DFRCC), and engineered cementitious composites (ECC). The model simulates the cracking of ordinary c...
Article
This article demonstrates the potential of a new extrinsic plastic optical fiber (POF) sensor for vibration-based structural health monitoring (SHM) applications. A simple genetic algorithm (GA) is used in conjunction with the POF sensor. The construction and principle of operation of the intensity-based POF sensor used in the study is described, h...
Article
This paper reports the results of an experimental program on the effect of steel loss and corrosion induced-damage (cracking, delamination, spalling, etc.) on the post-corrosion flexural response of reinforced concrete beams incorporating supplementary cementing materials (fly ash, slag and silica fume) used as partial replacement of ordinary Portl...
Article
In this paper, packaged fibre Bragg grating (PFBG) sensors were fabricated by embedding them in 70mm x 10mm x 0.3mm carbon-fibre composites which were then surface-bonded to an aluminium beam and a steel I-beam to investigate their strain monitoring capability. Initially, the response of these packaged sensors under tensile loading was compared to...
Article
This paper reports the use of fibre Bragg gratings (FBGs) as sensors for structural integrity assessment by monitoring the reduction in the flexural stiffness of a novel sandwich structure based on thermoplastic fibre-metal laminate (FML) skins and an aluminum-foam core. By monitoring the reduction in the structural flexural stiffness, the techniqu...
Article
This paper presents the results of an experimental research program designed to study the interfacial shear stress concentration at FRP cut-off points and the failure modes of RC beams strengthened in flexural with externally bonded carbon fibre reinforced polymer (CFRP) sheets. The test variables include the RC beam size and the CFRP thickness. Th...
Article
This paper presents the results of an experimental program designed to evaluate the performance of FRP-strengthened RC beams incorporating engineered cementitious composites (ECC) as a ductile layer around the main flexural reinforcement (ECC layered beams). The load-carrying and deflection capacities as well as the maximum FRP strain at failure ar...
Article
This paper describes the design of an extrinsic optical fibre sensors based on poly(methamethycrylate) for structural health monitoring applications. This polymer-based optical fiber sensor relies on the modulation of light intensity and is capable of monitoring the response of the host structure subjected to either static or dynamic load types. A...
Article
Plastic optical fibre sensors offer remarkable ease of handling and recent research has shown their potential as a low-cost sensor for damage detection and structural health monitoring applications. This paper presents details of a novel plastic optical fibre sensor and the results of a series of mechanical tests conducted to assess its potential f...
Article
The characteristics of engineered cementitious composites (ECCs) subjected to dynamic tensile loading and high-velocity projectile impact have been investigated and are reported in this paper. Hybrid-fiber ECC containing a combination of high-modulLIS steel fibers and relatively low modulus polyethylene fibers was adopted to achieve a desired balan...
Article
According to the available methods of analysis and design for reinforced concrete deep beams, addition of web reinforcement beyond the minimum amount provides only a marginal strength gain, if it does at all. This casts serious doubts on the feasibility and extent of strengthening by placing external reinforcement in the web, whenever such a need a...
Article
A one-way reinforced concrete (RC) slab was subjected to short-duration concentrated impact load and its dynamic characteristic for the virgin and damaged conditions were studied using two signal processing techniques. The recorded strain and acceleration signals were analyzed using the Fast Fourier Transform (FFT) and the Hilbert Huang Transform (...
Article
Plastic optical fibre sensors offer remarkable ease of handling, and recent research has shown their potential as a low-cost sensor for damage detection and structural health monitoring applications. This paper presents details of a novel extrinsic polymer-based optical fibre sensor and the results of a series of mechanical tests conducted to asses...
Article
Full-text available
This paper reports the feasibility of using embedded Fabry-Perot fiber optic sensors to detect and monitor the propagation of cracks and delamination within concrete beams induced by corrosion of the reinforcing bars. In this research, four series of reinforced concrete beams were subjected to varying degrees of corrosion-induced damage by modifyin...
Article
In recent years, increasing research efforts have been geared towards studying the repair and strengthening of concrete structures using fibre reinforced polymer (FRP) composites. Numerous studies have shown that structural members such as circular columns can experience a significant increase in strength and ductility due to passive confinement pr...
Article
Existing analytical models for predicting the stress–strain or load–displacement response of fibre-reinforced polymer (FRP)-confined concrete are mostly derived for cylindrical plain concrete columns. In practice, however, typical concrete columns come in various shapes including circular, square, or rectangular and incorporate longitudinal and tra...
Article
Full-text available
This paper reports the results of an experimental program on the effectiveness of a Ductile Fiber Reinforced Cementitious Composite (DFRCC) material, which exhibit strain-hardening and multiple-cracking bahavior under flexural loadings, in retarding the corrosion of steel in Reinforced Concrete (RC) beams. Based on the collective findings from theo...
Article
Full-text available
This paper reports the results of an experimental study on the strain-hardening behaviour of hybrid fibre reinforced cement composite under four-point bending. Two types of fibres (steel and PVA) were used as hybrid reinforcement in several volume fractions. The total volume fraction of fibres was kept constant at 2.5% to maintain a workable mix. E...
Article
An intelligent monitoring procedure has been applied to static and dynamic field data collected from two innovative structural systems that have recently been constructed in the provinces of Manitoba and Nova Scotia, Canada. These structures incorporate innovative materials and systems and have been extensively instrumented with both fiber optic an...
Article
This paper reports the results of an experimental programme designed to study the interfacial shear stress concentration at the plate curtailment of reinforced concrete (RC) beams strengthened in flexure with externally bonded carbon fibre-reinforced polymer (CFRP). Specifically, the study looks at the relationship between the CFRP plate thickness...
Article
Epoxy-bonding of FRP plates to the tensile face of RC beams has been shown to be an effective repair and strengthening technique. However, local failure by debonding or ripping of concrete cover has been reported in experiments to be a likely mode of failure due to high interfacial shear and normal stress concentrations. Predictive models for findi...
Article
The performance of conventionally reinforced concrete (RC) beams strengthened in flexure with externally bonded fiber-reinforced polymers (EB-FRP) was studied by compiling and analyzing an experimental database. A total of 127 specimens from 23 separate studies were included in the database. A profile of specimens in the database is given, followed...
Article
The influence of fiber rupture, fiber pull-out and fiber tensile strength distribution on the post-cracking behavior of short-randomly-distributed fiber reinforced brittle-matrix composites has been analyzed using an approach based on the Weibull weakest-link statistics. The analysis led to the development of a predicting model for the composite br...
Article
An experimental study on the simulation of corrosion in large-scale reinforced concrete columns and their repair using carbon fibre reinforced polymer (CFRP) sheets is presented. Seven columns were subjected to an accelerated corrosion regime, wrapped using CFRP sheets, then tested to structural failure and (or) subjected to further post-repair acc...
Article
This paper reports the results of an experimental program designed to provide a realistic assessment of the potential of using fiber-reinforced polymer (FRP) materials in the repair and strengthening of reinforced concrete (RC) flexural members. The experimental program included seven RC flexural beams 270 x 400 mm in cross section and 4350 mm in l...
Article
Although the concept of repairing and strengthening reinforced concrete (RC) structures using steel plate reinforcement has been established for more than 30 years, today there is an increasing trend toward the use of externally bonded fiber-reinforced polymer (FRP) composites, such as glass FRP and carbon FRP. This paper summarizes the results of...
Article
An intelligent monitoring procedure has been applied to fibre optic sensors (FOS) field data collected from an innovative structural system - The Taylor Bridge - in Headingley, Manitoba, Canada. The results show that FOS offer unique benefits for effective structural health monitoring of smart structures.
Article
A system identification procedure is developed for processing structural response signals registered by sensors permanently installed for monitoring at critical locations of a structure. The procedure, which is based on spectrogram estimation and is applied within a sweeping window of signal samples, was built into a data processing software that a...
Conference Paper
An experimental time-frequency analysis framework is developed for monitoring the occurrence and location of structural damage in instrumented structures such as bridges. We make available a software package written in Matlab that provides assistance in assessing the condition of the structural system with excellent visualization tools and interact...
Article
This paper reviews the mechanisms of toughening in unreinforced cementitious materials, including cement paste, mortar, and concrete. The paper emphasizes the microstructural aspects of the different fracture processes that can potentially take place in these materials, and point out any possible interactions between these processes. Reference is m...
Article
This paper reviews the mechanisms of toughening in fiber reinforced cement based composites. Reference is made to frontal, crack tip and wake processes, and estimates of contributions to composite toughness of the individual mechanisms are included. It is emphasized that the wake processes, which dominate the inelastic energy absorption during frac...
Article
Full-text available
In this paper, the tensile properties of cement-based composites containing random discontinuous steel fibers are reported. Direct tensile tests were performed to study the effects of fiber length (hence fiber aspect ratio), interfacial bonding, and processing conditions on composite properties. Composite tensile strength and ductility are highligh...
Article
In this paper, the results of an experimental study on the effect of fiber volume fraction on the off-crack-plane fracture energy in a strain-hardening engineered cementitious composite (ECC) are presented. Unlike the well-known quasi-brittle behavior of fiber-reinforced concrete, ECC exhibits quasi-ductile response by developing a large damage zon...
Article
Full-text available
A probabilistic-based micromechanical model has been developed for the postcracking behavior of a brittle matrix reinforced with short, randomly distributed fibers. The model that predicts the composite bridging stress crack-opening displacement (GOD) relationship, accounts for fiber pullout, fiber tensile rupture, and a local frictional effect cal...