Towards efficient structural and serviceability design of high-strength concrete t-beams

A total of 10 HSC T-beams having a total length of 1700 mm, web breadth of 100 mm, height of 250 mm, and different flange dimensions, were experimentally tested until failure. The studied parameters were; flange dimensions, transverse reinforcement ratio, and longitudinal reinforcement ratio of the beam. A numerical model was developed to predict the flexural behaviour of the tested beams. The results indicated that increasing breadth, depth, and flange reinforcement ratio led to reduction in the overall deflection, and enhancment of the ultimate load capacity. An empirical equation, developed earlier by the authors for predicting effective moment of inertia for HSC T beams, was used successfully to predict load-deflection relationships for the studied beams. Comparisons were carried out between the load-deflecion curves predicted by the numerical model, those predicted by this equation, and those predicted by Branson equation which is currently used in the design codes. It was found that there was a close agreement between the experimental results, numerical results and those obtained by the authors’ equation. This research highlights the need for updating the Branson equation used in the design codes for deflection design of HSC T beams by adopting the equation proposed by the authors

Towards efficient structural and serviceability design of high-strength concrete T-beams

A total of 10 HSC T-beams having a total length of 1700 mm, web breadth of 100 mm, height of 250 mm, and different flange dimensions, were experimentally tested until failure. The studied parameters were; flange dimensions, transverse reinforcement ratio, and longitudinal reinforcement ratio of the beam. A numerical model was developed to predict the flexural behaviour of the tested beams. The results indicated that increasing breadth, depth, and flange reinforcement ratio led to reduction in the overall deflection, and enhancment of the ultimate load capacity. An empirical equation, developed earlier by the authors for predicting effective moment of inertia for HSC T beams, was used successfully to predict load-deflection relationships for the studied beams. Comparisons were carried out between the load-deflecion curves predicted by the numerical model, those predicted by this equation, and those predicted by Branson equation which is currently used in the design codes. It was found that there was a close agreement between the experimental results, numerical results and those obtained by the authors’ equation. This research highlights the need for updating the Branson equation used in the design codes for deflection design of HSC T beams by adopting the equation proposed by the authors

SERVICEABILITY BEHAVIOR OF NORMAL AND HIGH-STRENGTH REINFORCED CONCRETE T-BEAMS

Serviceability behavior of Normal Strength Concrete (NSC) and High Strength Concrete (HSC) T-beams was experimentally evaluated. The crack pattern was observed, the effect of flange dimensions (breadth and thickness) on the crack pattern and load-deflection response was evaluated experimentally for 10 beams comprising the two studied groups, NSC and HSC T-beams. The short-term deflections were measured experimentally and predicted empirically under mid-span concentrated loading. It was found that increasing the flange width and thickness resulted in higher loads and lower deflections under service loads to a different extent. Prior to failure, the increment in the maximum loads was up to 22% while the deflection reduced by 31% for NSC and 23% for HSC beams. The available equations for determining the effective moment of inertia (Ie) were reviewed and used in predicting the Ie of the cracked beam. The results were compared with the experimental values (Iexp). The Ie showed a noticeable difference, especially for the HSC T-beams. New equations were proposed in which the tensile reinforcement ratio was considered. Compared with the other available equations, the proposed equations demonstrated a better agreement and repeatability of predicting experimental results studied herein. In addition, the proposed equations were used to predict the Ie for experimentally tested T-beams available in the literature. The proposed models showed a high degree of accuracy

Enhancement of punching shear behavior of reinforced concrete flat slabs using GFRP grating

The literature review showed insufficient relevant research on the application of Glass-Fiber-Reinforced-Polymers (GFRP) gratings in the structural elements, while GFRP bars, laminate, sheets, and strips, have been extensively explored. This research aims to present a proposal for a new reinforcing system using GFRP gratings to improve the punching shear resistance of RC flat slabs. Results of seven specimens tested experimentally under vertical static loading are displayed, taking into account the influence of the gratings variables. Test results revealed an improvement in the ultimate load ranging between 9.03% and 27.67% for the specimens strengthened by the proposed GFRP grating system. A Nonlinear Finite Element Analysis (NLFEA) was carried out using the ANSYS program with correlational evaluation using load-deflection response and cracking pattern, which resulted in a good convergence of numerical simulations and experimental performance results ranging from 1.0% to 8.0%. Key parameters, namely the concrete compressive strength, steel reinforcement yield strength, main steel reinforcement ratio, secondary steel reinforcement ratio, column dimensions, slab thickness, concrete cover, and GFRP gratings characteristics, were investigated through a parametric study adopting NLFEA by the ANSYS program, where the output results were compared to the recent code provision

Center practice drives variation in choice of US kidney transplant induction therapy: a retrospective analysis of contemporary practice

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141776/1/tri13079_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141776/2/tri13079.pd

Genetic and Morphological Diversity Assessment of Five Kalanchoe Genotypes by SCoT, ISSR and RAPD-PCR Markers

Determining the appropriate parents for breeding programs is the most important decision that plant breeders must make to maximize the genetic variability and produce excellent recombinant genotypes. Several methods are used to identify genotypes with desirable phenotypic features for breeding experiments. In this study, five kalanchoe genotypes were morphologically characterized by assessing plant height, number of inflorescences, number of flowers, flower length, flower diameter and number of petals. The analysis showed the distinction of yellow kalanchoe in the plant height trait, while the orange kalanchoe was distinguished in the number of inflorescences, the number of flowers and flower length traits, whereas the violet kalanchoe possessed the largest flower diameter and the highest number of petals. The molecular profiling was performed by random amplified polymorphism DNA (RAPD), inter-simple sequence repeats (ISSR) and start codon targeted (SCoT)-polymerase chain reaction (PCR) tools. Genomic DNA was extracted from young leaves and the PCR reactions were performed using ten primers for each SCoT, ISSR and RAPD marker. Only four out of ten primers showed amplicon profiles in all PCR markers. A total of 70 bands were generated by SCoT, ISSR and RAPD-PCR with 35 polymorphic bands and 35 monomorphic bands. The total number of bands of RAPD, ISSR and SCoT was 15, 17 and 38, respectively. The polymorphism percentages achieved by RAPD, ISSR and SCoT were 60.25%, 15% and 57%, respectively. The cluster analysis based on morphological data revealed two clusters. Cluster I consisted of violet and orange kalanchoe, and cluster II comprised red, yellow and purple kalanchoe. Whereas the cluster analysis based on molecular data revealed three clusters. Cluster I included only yellow kalanchoe, cluster II comprised orange and violet kalanchoe while cluster III comprised red, and purple kalanchoe. The study concluded that orange, violet and yellow kalanchoe are distinguished parents for breeding economically valued traits in kalanchoe. Also, the study concluded that SCoT and RAPD markers reproduced reliable banding patterns to assess the genetic polymorphism among kalanchoe genotypes that consider the basis stone for genetic improvements in ornamental plants