Over the last two decades Fiber Reinforced Polymers have emerged as an attractive competitor to the more conventional civil engineering materials for the creation of new structures and the strengthening/rehabilitation of existing ones [1-book]. Therefore many related associations such as ACI committee provided practical design manuals for all aspects of application FRPs for strengthening structural elements. The comparison between experimental and analytical code based studies performs previously for shear strengthening of RC beam with FRP composites is not very promising. Specially for shear strengthening the use of additional principle in the actual shear design equations must be questioned.[] The large dispersion between the expected values of different models and experimental results is of real concern bearing in mind some of this semi-empirical models are applied to present design codes. [01-arc] Shear strengthening of RC members with FRP is actually a research problem have not been completely solved and is still under investigation; [2-ar] so that the trustworthiness of existing models to achieve reliable and safe codification needs to be evaluated. Many uncertainties and complicated problems have assessed so far for strengthening of RC beams with FRPs are: real effective strain of FRPs in shear strengthening [Chen & Teng 2003a], main failure modes recognized for each section configuration, most accurate evaluation model [03-arc], and interactions between the external
ACI 318-63 requires that the minimum ratio of longitudinal bars shall be at least 1.0%. Also, The vertical center-to-center spacing of the lateral ties shall be one of the smallest of: (1) 16 longitudinal bar diameters to restrain longitudinal bars from buckling, (2) 48 tie diameters to ensure sufficient tie area to restrain the lateral displacement of the reinforcing bars, and (3) the least lateral dimension of the column to develop the maximum strength of the concrete core. As shown in Fig. 1, The dimensions and steel reinforcement details of the columns involved in this experimental program were particularly selected to represent relatively older columns. In this experimental program, the longitudinal reinforcement ratio, ρl, was constant
The goal of the beam project is to design and construct a beam that can hold a given amount of weight without breaking. The beam is required to hold a concentrated load of 375 lbf on the X-axis and 150 lbf on the Y-axis. The maximum allowable weight of the beam is 250 grams. The maximum allowable deflection for the beam is 0.230 in. and 0.200 in. for the X and Y-axis respectively. The beam is required to be 24 in. in length, and it will be tested on a simply supported configuration spanning 21 in. All calculations are to be done under the assumption that the density of basswood is 28 lbm/ft3 and the modulus of elasticity for basswood is 1.46x106 lbm/in2. Given the constraints of a spending cost of $10.50, a maximum beam weight of 250 grams,
This report aims to describe the experiment performed to investigate the stiffness of a channel section, and in particular calculate the flexural rigidity (EI) of the beam by two different sets of calculations based on the results gained in the experiment. The EI of an object is used
As the human body ages, it becomes more fragile. America’s infrastructure is nearly the same. With the everyday use of many large structures, such as bridges, buildings, and other large structures made of concrete and/or steel, many are beginning to wither away while the average American is unaware of these changes. In many projects around the world, there is a material that is being commonly used to strengthen structures known as Carbon Fibre Reinforced Polymer (CFRP). The types of structures that this material can help to strengthen includes, but is not limited to, reinforced concrete columns, bridge girders, steel structures, and cable
Steel-reinforced concrete is a widely used structural material. The effectiveness of the steel reinforcement depends on the bond between the steel reinforcing bar and the concrete. Reinforced concrete is a composite material in which concrete 's relatively low tensile strength and ductility are counteracted by the inclusion of reinforcement having higher tensile strength and ductility. The reinforcement is usually, though not necessarily, steel reinforcing bars and is usually embedded passively in the concrete before it sets. Reinforcing schemes are generally designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and
The Cree Indian prophecy stated that, Only when the last tree has been cut down, the last fish caught, and the last stream poisoned, will we realise we cannot eat money. Water is something in such abundance that is available to us at the turning of a faucet, so much that we tend to take it for granted and forget its global impact. We need to stand together and protect clean potable water when our watershed is being threatened. Water is our most precious resource, without it, life itself would seem to exist.
I chose to analyze this research article which tries to answer if major depressive disorders in parents lead to specific fears and phobias in offspring, because I like psychology and I wanted an article that was related some way to this interest.
A Chakraborty et al [1] have studied the thermo-elastic behavior of functionally graded beam structures based on the first-order shear deformation theory and these properties are varying along its thickness. The governing differential equations are used to construct interpolating polynomials for the element formulation. To determine various stresses, both exponential and power-law variations of material property distribution are used. Thermal behaviors of functionally graded beam (FGB) by taking the distribution of material properties in exponential function were analyzed by GH Rahimi and AR Davoodinik [2]. The steady state of heat conduction with exponentially and hyperbolic variations through the thickness were consider for the use of thermal loading. They found that thermal behavior of both isotropic beam and functionally graded beam depend up on the temperature distribution.
This Bayesian Network diagram illustrate if a patient is affected by diabetes and the steps he or she can take to figure out how to go about treatment, cost and how to control the diabetes.
Abstract: Advancement in recent years on the efficiency of glass fiber-reinforced polymer (GFRP) in production and cost benefits have increased their use as alternative means to steel rebar in bridge deck bases. The purpose in applying rebar is to increase the tensile strength of concrete. Considering the versatility of bridges there are many factors that need to be analyzed when choosing whether to use steel rebar or GFRP material such as: cost, tensile strength, and weather resistance. Stress-strain graphs were calculated, graphed, and analyzed to determine the yield tensile strength and stiffness of steel rebar and GFRP. Data collected from alkaline bath tests were graphed and analyzed to determine the thermal and corrosion resistance of each material. Costs per square inch of each material were also compared as well as each materials quality and life expectancy. The results of the conducted test analysis found the GFRP to have greater thermal resistance, lower cost, and higher life expectancy than the steel rebar, however the steel rebar’s stiffness was found to be about six times larger than the GFRP’s. These results suggest that the advancements in GFRP can provide longer lasting bridge structures and will change the future of construction and restoration of bridges.
The article “Reliability based design applied to retaining walls”, by Bak Kong Low seek to introduce a different approach on design procedures for retaining walls. It involves achieving a homogenous result as the Hasofer-Lind reliability index and first-order reliability method (FORM), using Microsoft Excel, in an intuitive expanding dispersion ellipsoid perspective. The method, claimed by the author, provides more straightforward computations and interpretations of the aforementioned reliability-based design procedures. It is emphasised that the article considered the methodology and concepts with respect to reliability based design, and not in its widest aspect (Low, 2005). Hence, the author illustrated the practical spreadsheet-automated reliability analysis through two cases. One is a simple retaining wall with two random variables and the other one is an anchored retaining wall with nine random variables. For the latter case, it was considered as correlated normal variates initially and correlated non-normals after that. The intuitive expanding dispersion ellipsoid perspective and the definition of reliability index were explained in the main body of the paper. Any limitations, correlations and uncertainties were discussed briefly as well.
Introduction: It has been well established that drilling of FRP’s lead to drilling induced damage thus reducing component’s life and reliability. Thrust force induced in drilling of FRPs is one of the major reasons for drilling induced damage [1]. Several studies have been made worldwide to critically review the delamination induced in drilling of FRPs. These research efforts clearly indicate direct relationship of damage induced with thrust force induced during drilling of FRPs [2-6]. Various mechanistic, mathematical and analytical models have been developed based on different reasoning,
It is well-known that many reinforced concrete columns including particularly those RC columns constructed prior to the 1970s have been reinforced with an inadequate amount of transverse steel reinforcement which provides inefficient confinement to the concrete core or lateral restrain to the longitudinal reinforcing bars. Since the FRP composites owe some of the extraordinary properties such as high strength-to-weight ratio and excellent corrosion resistance, the use of externally bonded FRP composites has significantly increased in the construction industry. As confinement jackets, using FRP techniques is nowadays become one of the most popularly innovative confining means for upgrading existing RC structures. Therefore, several experimental studies have been carried out to date, such as on retrofitting or strengthening those structures with FRP systems, for example. In case of rarely sever seismic loads, establishing an axial stress-strain model considering cyclic axial compressive load is, in turn, imperative for simulating FRP-confined RC columns subjected to earthquake loads and performing a proper seismic design of such FRP-jacketed RC Columns, which are typically subjected to both axial and lateral force Wang et al.(2012). A uniaxial stress-strain model can be developed from laboratory testing results on axially loaded concrete columns confined with fiber-reinforcement polymer (FRP) composites and can then be applied as the constitutive law for confined concrete
FRP composites having superior material properties when compared with metals, improved corrosion resistance, fatigue resistance, less weight to strength ratio and high fracture toughness. Hence GFRP composites frequently used in several applications like sports goods, racing car bodies and aerospace components [1]. Often composite products manufactured by near-net shapes. The components made by secondary machining processes are involving to get good dimensional accuracy and
Among the various disasters in the world, earthquakes have caused lots of losses and damage to structures and lifelines. Thus, evaluating the seismic responses of such structures is essential to disaster risk reduction programs. In disaster planning, buildings are the important structures which should be prepared with strongly resistance to earthquake. Myanmar is earthquake prone area and one of the major active faults is Sagaing fault which is known to have produced significant earthquakes in the past. The history of the region indicates that there was a strong possibility of major earthquakes occurrence and suffered immense losses of life and property.