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Full-Text Articles in Engineering
Sources Of End Zone Cracking Of Pretensioned Concrete Girders, Christie J. Hasenkamp, Sameh S. Badie, Christopher Y. Tuan, Maher K. Tadros
Sources Of End Zone Cracking Of Pretensioned Concrete Girders, Christie J. Hasenkamp, Sameh S. Badie, Christopher Y. Tuan, Maher K. Tadros
Christopher Y. Tuan
Recent developments of high performance concrete, increasing amounts of prestressing, and increasing use of deep girders have resulted in increasing popularity of precast pretensioned concrete girders in bridge construction. These developments have increasingly contributed to end zone cracking. This paper summarizes the interim results of an ongoing research sponsored by the National Cooperative Highway Research Program (NCHRP) Project 18-14. The objectives of the research are: (1) to establish procedures for the acceptance, repair, or rejection of precast/prestressed concrete girders with longitudinal web cracking, and (2) to prepare a user's manual for the application of these procedures. The results from a …
Increasing The Flexural Stiffness Of Frp Wrapped Reinforced Concrete Columns, Muhammad Hadi, Veysel Yazici
Increasing The Flexural Stiffness Of Frp Wrapped Reinforced Concrete Columns, Muhammad Hadi, Veysel Yazici
Veysel Yazici
Axial load carrying capacity of reinforced concrete columns increase substantially after FRP wrapping. However, the same method also increases the lateral deformation capacity 61the columns especially under eccentric loads implying that secondary moments have to be considered when column are wrapped with FRP sheets under high level of axial loads. In this experimental study, six circular RC columns were cast and divided into two groups which were tested under 25 mm and 50 mm eccentric axial loads. Both groups had an unwrapped RC column, a three layers FRP wrapped column in the hoop direction, and a column which had discrete …
Normalized Confinement Stiffness Approach For Modeling Frp-Confined Concrete, Veysel Yazici, Muhammad N. S Hadi
Normalized Confinement Stiffness Approach For Modeling Frp-Confined Concrete, Veysel Yazici, Muhammad N. S Hadi
Veysel Yazici
Passive confinement provided by fiber-reinforced polymer (FRP) jackets increases the compressive strength and axial deformation capacity of concrete. This study explains a normalized confinement stiffness approach to quantify the strength and strain increase of FRP confined concrete using a previously proposed and most widely-used model for both active and passive confinement of concrete, and claims that these equations can still be used for FRP-confined concrete with very simple modifications. A comparison of the proposed model's accuracy to American Concrete Institute guidelines was made using experimental results reported in the literature. The proposed modified model was shown to be quite effective …
Utilising Non-Composite Steel-Concrete-Steel Panels For Protective Structures, A M. Remennikov, S Y. Kong, Brian Uy
Utilising Non-Composite Steel-Concrete-Steel Panels For Protective Structures, A M. Remennikov, S Y. Kong, Brian Uy
Alex Remennikov
A high-performance protective structure utilising non-composite steel-concrete-steel (SCS) sandwich panels for protecting buildings and facilities against close-range detonation of VBIEDs and heavy ve-hicle impacts has been developed. Unlike other existing composite sandwich panels, no shear connec-tors between the steel faceplates are utilised to construct protective panels in order to simplify the con-struction process. The concrete core of the panel is included to provide the mass for increased inertia effects, and the steel faceplates are designed to develop tensile membrane resistance at large displace-ment to dissipate impulsive energy. The energy dissipation capability and high ductility of the axially-restrained non-composite SCS panels …
Reliability-Based Conversion Of A Structural Design Code For Railway Prestressed Concrete Sleepers, A M. Remennikov, Martin Murray, Sakdirat Kaewunruen
Reliability-Based Conversion Of A Structural Design Code For Railway Prestressed Concrete Sleepers, A M. Remennikov, Martin Murray, Sakdirat Kaewunruen
Alex Remennikov
"Ballasted railway track is very suitable for heavy-rail networks because of its many superior advantages in design, construction, short- and long-term maintenance, sustainability, and life cycle cost. An important part of the railway track system, which distributes the wheel load to the formation, is the railway sleeper. Improved knowledge has raised concerns about design techniques for prestressed concrete (PC) sleepers. Most current design codes for these rely on allowable stresses and material strength reductions. However, premature cracking of PC sleepers has been found in railway tracks. The major cause of cracking is the infrequent but high-magnitude wheel loads produced by …
The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy
The Response Of Axially Restrained Non-Composite Steel-Concrete-Steel Sandwich Panels Due To Large Impact Loading, Alex M. Remennikov, Sih Ying Kong, Brian Uy
Alex Remennikov
In conventional steel-concrete-steel (SCS) construction, the external steel plates are connected to the concrete infill by welded shear stud connectors. This paper describes a programme of experimental and numerical investigations on reduced-scale non-composite SCS panels with axially restrained connections. The experimental results have demonstrated that the non-composite SCS panels are capable of developing enhanced load-carrying capacity through the tensile membrane resistance of the steel faceplates. This type of construction was found to exhibit highly ductile response and be able to sustain large end rotations of up to 18° without collapse. High fidelity finite element models for SCS panels under impact …
Simulation Of The Reinforced Concrete Slabs Under Impact Loading, Faham Tahmasebinia, Alexander Remennikov
Simulation Of The Reinforced Concrete Slabs Under Impact Loading, Faham Tahmasebinia, Alexander Remennikov
Alex Remennikov
Many older structures were designed for static loads but more recently there has been a growing awareness that some must be designed to resist both dynamic impact and static loads. An accidental impact load can be caused by mishaps in industry as well as accidents stemming from transportation or man-made disasters. There are number of ways of predicting how an impact load will affect a concrete slab, some of which may be impractical or expensive but because there have been significant developments in technology, numerical techniques rather than experimental approaches have become popular methods for developing detailed responses Therefore, to …
End Zone Reinforcement For Pretensioned Concrete Girders, Christopher Y. Tuan, Sherif A. Yehia, Nipon Jongpitaksseel, Maher K. Tadros
End Zone Reinforcement For Pretensioned Concrete Girders, Christopher Y. Tuan, Sherif A. Yehia, Nipon Jongpitaksseel, Maher K. Tadros
Christopher Y. Tuan
In this study, a literature review was conducted to establish the background of current specifications and to evaluate the applicability of various theories and methods for design of end zone reinforcement. Analytical methods reviewed in this paper include finite element analysis, strut-and-tie modeling, and the Gergely-Sozen equivalent beam method. Previous experimental work combined with work conducted as part of this study was used to correlate between various theoretical and experimental results. This paper illustrates that no single theoretical method adequately represents the complex behavior at the end of a pretensioned concrete member. A general semi-empirical design procedure is proposed here. …
Curved, Precast, Pretensioned Concrete I-Girder Bridges, Wilast Amorn, Christopher Y. Tuan, Maher K. Tadros
Curved, Precast, Pretensioned Concrete I-Girder Bridges, Wilast Amorn, Christopher Y. Tuan, Maher K. Tadros
Christopher Y. Tuan
Modern highway construction frequently requires bridges with horizontally curved alignments. Such bridges can be created by superimposing a curved deck slab onto straight girders or by splicing segmental straight girders on the chords of a curved roadway. Of these two methods, a curved superstructure usually results in simpler construction and better appearance.
Bond Strength And Transfer Length Of Pre-Tensioned Bridge Girders Cast With Self-Consolidating Concrete, Amgad Girgis, Christopher Tuan
Bond Strength And Transfer Length Of Pre-Tensioned Bridge Girders Cast With Self-Consolidating Concrete, Amgad Girgis, Christopher Tuan
Christopher Y. Tuan
Self-consolidating concrete (SCC) is becoming increasingly popular in the precast/prestressed concrete industry in the United States. However, there have been concerns regarding the bond strength, transfer length, and development length of prestressing strands and mild steel reinforcement with SCC. Further, there are no design guidelines for using SCC. In this study, a literature survey on the bond strength of SCC was conducted. Moustafa pullout tests were performed to determine the bond strength of 0.6 in. (15.2 mm) pretensioning strands with sec. The transfer lengths of three pretensioned concrete bridge girders were measured using Demec points. Pullout tests were also performed …
Hybrid Frp-Concrete Railway Sleeper, Wahid Ferdous, Amar Khennane, Obada Kayali
Hybrid Frp-Concrete Railway Sleeper, Wahid Ferdous, Amar Khennane, Obada Kayali
Wahid Ferdous
The aim of this research was to investigate the feasibility of a hybrid FRP-concrete beam as a rail sleeper. It was hoped that the new design would overcome some of the sustainability issues associated with traditional sleepers. The hybrid system consisted of a Rectangular Hollow Section (RHS) pultruded profile filled with geo- polymer concrete. The specimens were tested in a four-point bending setup to determine the flexural properties such as the bending modulus (E) and modulus of rupture (MOR). It was found that the proposed composite beam satisfied the minimum flexural requirements for composite railway sleepers as stated in the …
Affordable Lightweight High Performance Concrete (Alwhpc) - Expanding The Envelope Of Concrete Mix Design, Kevin J. Simons
Affordable Lightweight High Performance Concrete (Alwhpc) - Expanding The Envelope Of Concrete Mix Design, Kevin J. Simons
Kevin J Simons
One way to reduce excess material would be to lighten the load on a structure with the use of affordable lightweight high performance concrete (ALWHPC). Most or all lightweight high performance concrete mixes used today include lightweight aggregates as the coarse aggregate and sand for the fine aggregate. ALWHPC mix designs contain all lightweight aggregates and cementitious materials that are readily available throughout the United States. Instead of 115 – 120 pcf, ALWHPC mix designs range from 88 – 100 pcf and strengths from 2,700 – 8,700 psi compressive strength. This research will explore the use of local lightweight aggregates …