This paper presents a study (experimentally) for strengthening reinforced concrete (RC) beams with Near-Surface-Mounted (NSM) technique. The use of this technique with CFRP strips or rebars is an efficient technology for increasing the strength for flexure and shear or for repairing damaged reinforced concrete (RC) members. The objective of this research is to study, experimentally, RC beams either repaired or strengthened with NSM CFRP strips and follow their flexural behavior and failure modes. NSM-CFRP strips were used to strengthen three RC beam specimens, one of them was initially strengthened and tested up to failure. Four beam specimens have been initially subjected to preloading to 50% and 80% of ultimate load. Two of the specimens were either repaired or strengthened with NSM-CFRP strips. All the repaired/strengthened pre-damaged beams have been tested up to failure by using compression-testing machine. An appropriate-scale model was adopted. All the specimens have a cross-sectional dimension of 150 mm with an effective span of 110 mm. Depends on the experimental results, a better performance of the strengthened concrete specimens was obtained in both strength and serviceability. As a comparison with the control beam specimen, all the repaired specimens show a very good increase of about 40% in the load-carrying capacity and a high improvement in resistance to cracking of about 120% in NSM. On the other hand, the test results of NSM CFRP-strengthened concrete specimens with a preloading of 50% and 80% of the ultimate load show an increase of about 9% to 20% in the load-carrying capacity, for 50% and 80% pre-loading, respectively an improvement in deflection of about 2% to 27% in NSM, for 80% and 50% pre-loading, respectively.
Phosphorus (P) is an element that is potatoes require in large amounts. Soil pH is a crucial factor impacting phosphorus availability in potato production. This study was conducted to evaluate the influence of P application rates on the P efficiency for tuber yield, specific gravity, and P uptake. Additionally, the relationship between soil pH and total potato tuber yield was determined. Six rates of P fertilization (0–280 kg P ha−1) were applied at twelve different sites across Northern Maine. Yield parameters were not responsive to P application rates. However, regression analysis showed that soil pH was significantly correlated with total potato tuber yield(R2 = 0.38). Sites with soil pH values < 6 had total tuber yields,
... Show MoreIn this paper, an exact stiffness matrix and fixed-end load vector for nonprismatic beams having parabolic varying depth are derived. The principle of strain energy is used in the derivation of the stiffness matrix.
The effect of both shear deformation and the coupling between axial force and the bending moment are considered in the derivation of stiffness matrix. The fixed-end load vector for elements under uniformly distributed or concentrated loads is also derived. The correctness of the derived matrices is verified by numerical examples. It is found that the coupling effect between axial force and bending moment is significant for elements having axial end restraint. It was found that the decrease in bending moment was
in the
This paper studied the behaviour of reinforced reactive powder concrete (RPC) two-way slabs under static load. The experimental program included testing three simply supported slabs of 1000 mm length, 1000 mm width, and 70 mm thickness. Tested specimens were of identical properties except their steel fibers volume ratio (0.5 %, 1 %, and 1.5 %). Static test results revealed that, increasing steel fibers volume ratio from 0.5% to 1% and from 1% to 1.5%, led to an increase in: first crack load by (32.2 % and 52.3 %), ultimate load by (36.1 % and 17.0 %), ultimate deflection by (33.6 % and 3.4 %), absorbed energy by (128 % and 20.2 %), and the ultimate strain by (1.1 % and 6.73 %). The stiffness and ductility of the specimens also increased. A
... Show MoreThe present study focused mainly on the buckling behavior of composite laminated plates subjected to mechanical loads. Mechanical loads are analyzed by experimental analysis, analytical analysis (for laminates without cutouts) and numerical analysis by finite element method (for laminates with and without cutouts) for different type of loads which could be uniform or non-uniform, uniaxial or biaxial. In addition to many design parameters of the laminates such as aspect ratio, thickness ratio, and lamination angle or the parameters of the cutout such as shape, size, position, direction, and radii rounding) which are changed to studytheir effects on the buckling characteristics with various boundary conditions. Levy method of classical lam
... Show More40 blood sample were taken from children infected with kala-azar at age less than ten years, who were admitted to El-Eskan child hospital, and central health laboratory in Baghdad. At the same time 15 sample collected from healthy child for comparing. During research estimated immunoglobulins level ( IgG, IgM, IgA) and (IFAT) IFAT test recorded a higher indicate antibodies level witch was synergistic with infected severity, the stander level of antibodies arrange between 1/16, 1/32 and 1/64 that means it graduate from the lowest one 1/16 into the highest one 1/64 within groups. During infectious the IgG ,IgM level recorded the higher level (2012.9 mg/dl) and (154.3 mg/dl) compared to the control group (874.3 mg/dl),
... Show MorePushover analysis is an efficient method for the seismic evaluation of buildings under severe earthquakes. This paper aims to develop and verify the pushover analysis methodology for reinforced concrete frames. This technique depends on a nonlinear representation of the structure by using SAP2000 software. The properties of plastic hinges will be defined by generating the moment-curvature analysis for all the frame sections (beams and columns). The verification of the technique above was compared with the previous study for two-dimensional frames (4-and 7-story frames). The former study leaned on automatic identification of positive and negative moments, where the concrete sections and steel reinforcement quantities the
... Show MoreIn this article, Convolution Neural Network (CNN) is used to detect damage and no damage images form satellite imagery using different classifiers. These classifiers are well-known models that are used with CNN to detect and classify images using a specific dataset. The dataset used belongs to the Huston hurricane that caused several damages in the nearby areas. In addition, a transfer learning property is used to store the knowledge (weights) and reuse it in the next task. Moreover, each applied classifier is used to detect the images from the dataset after it is split into training, testing and validation. Keras library is used to apply the CNN algorithm with each selected classifier to detect the images. Furthermore, the performa
... Show MoreIn this study, nanocomposites have been prepared by adding
multiwall carbon nanotubes (MWCNTs) with weight ratios (0, 2, 3,
4, 5) wt% to epoxy resin. The samples were prepared by hand lay-up
method. Influence of an applied load before and after immersion in
sodium hydroxide (NaOH) of normality (0.3N) for (15 days) at
laboratory temperature on wear rate of Ep/MWCNTs
nanocomposites was studied. The results showed that wear rate
increases with increasing the applied load for the as prepared and
immersed samples and after immersion. It was also found that epoxy
resin reinforced with MWCNTs has wear rate less than neat epoxy.
The sample (Ep + 5wt% of MWCNTs) has lower wear rate. The
immersion effect in base so