A Study of the Deflection and Strength of Partially Prestressed Concrete Beams with Unbonded Tendons PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download A Study of the Deflection and Strength of Partially Prestressed Concrete Beams with Unbonded Tendons PDF full book. Access full book title A Study of the Deflection and Strength of Partially Prestressed Concrete Beams with Unbonded Tendons by K.-Y. Chu. Download full books in PDF and EPUB format.
Author: K.-Y. Chu
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: K.-Y. Chu
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Author: Kenan Mostafa Arshad
Publisher:
ISBN:
Category :
Languages : en
Pages : 252
Get Book Here
Book Description
Author: Murad Jaafar
Publisher:
ISBN:
Category : Concrete beams
Languages : en
Pages : 144
Get Book Here
Book Description
Te primary objective of this experimental investigation was to study flexural cracking behaviour and deflection of partially prestressed post tensioned beams. Fourteen T beams with various combinations of prestressed steel wires adn non prestressed steel bars were tested to failure. Each beam was simply supported on a simple span of 2.74m and was subjected to two symmetrical point loads. The number of prestressed steel wires and the non prestressed deformed bars was selected as being the main controlling parameter ofthis experimental investigation. The deflection, strain distribution and crack width of concrete beams were recorded at different loading stages. The experimental results form tests were compared with theoretical analysis and other empirical formulate as proposed by some researchers. It was observed that the crack initiation and propagation in partially prestressed beams with unbonded tendons depended on many factoes. The results agreed well with the findings os some researchers but were not in close agreement with other workers possibly because the beams were subjected to different conditions particularly due to unbonded tendons.
Author: Karmen Tso
Publisher: Open Dissertation Press
ISBN: 9781361429167
Category :
Languages : en
Pages :
Get Book Here
Book Description
This dissertation, "Full-range Behaviour of Concrete Beams Partially Prestressed With Unbonded Tendons" by Karmen, Tso, 曹嘉雯, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: ABSTRACT OF THESIS ENTITLED Full-range Behaviour of Concrete Beams Partially Prestressed with Unbonded Tendons submitted by TSO Karmen for the degree of Master of Philosophy at The University of Hong Kong in February 2007 External prestressing can be applied to both new construction and retrofitting of existing reinforced and prestressed concrete structures. The behaviour of prestressed concrete structures with unbonded tendons differs significantly from that of those with bonded tendons after the working stage. To assess the safety of such structures, it is necessary to carry out full-range analysis, with particular attention to the post-peak behaviour. This thesis presents the results of an experimental study of externally prestressed concrete beams with either conventional or non-conventional tendons, which were tested to failure. The specimens tested all had T-sections prestressed by two external tendons with one on each side. Two types of tendon were used, namely 7-wire steel strands of 10.5 mm diameter and aramid fibre reinforced polymer (AFRP) tendons of 13.5 mm diameter. Unlike the steel tendons, the fibre reinforced polymer (FRP) tendons are not prone to corrosion. However, the prestressing operations for FRP tendons had to be modified to suit. In the experiments, different factors were taken into consideration. They included the level of prestressing force, concrete strength, area of non-prestressed steel reinforcement and partial prestressing ratio. - 1 - The full-range behaviour of partially prestressed concrete with either external unbonded steel or fibre reinforced polymer (FRP) tendons was significantly affected by second-order effects, as demonstrated in the strain profiles of top and bottom non- prestressed reinforcement and the variations of curvature and neutral axis depth. During the investigation of tendon force, the friction loss at deviator was found to be much greater than the friction loss estimated from the coefficients of friction given by the manufacturers. The equivalent coefficients of friction of steel and AFRP tendon were studied. Lastly, by using various ductility and deformability indices, the ductility or deformability of partially prestressed concrete with external unbonded tendons were investigated. The most suitable ductility or deformability index is proposed. (TSO Karmen) (302 words) - 2 - DOI: 10.5353/th_b3822557 Subjects: Tendons (Prestressed concrete) - Testing Prestressed concrete beams - Testing
Author: FADI MAAZ ALKHAIRI
Publisher:
ISBN:
Category :
Languages : en
Pages : 916
Get Book Here
Book Description
from 15 different investigations. Excellent correlation was obtained between predicted vs. experimental results. The present investigation suggests that shear deformations may have some effect on the stress increase in unbonded tendons for beams having low span-to-depth ratios, while eccentricity variations in external tendons significantly affect the overall behavior for beams having high span-to-depth ratios.
Author: Adi Abu-Obeidah
Publisher:
ISBN:
Category : Concrete beams
Languages : en
Pages : 135
Get Book Here
Book Description
The use of unbonded tendons in prestressed concrete beams has been widely utilized in bridges, parking structures, and residential buildings for strengthening, rehabilitation or repair of such members. With the growth of live load and the increase of damaged concrete members, there is a need to develop and utilize new techniques for more efficient and improved designs in prestressed concrete members. This research presents an experimental and analytical investigation for the use of combination of bonded and unbonded tendons in the same concrete members. With the availability of high strength concrete, as well as the development of new prestressing technologies, the process can be easily performed at the site for repair or capacity upgrading resulting in longer spans for the same section depth or shallower sections. There is a knowledge gap on the behavior of concrete beams prestressed with hybrid tendons and a need to fully understand their overall behavior under full service loads. The hybrid technique introduces unbonded CFRP tendons, which is resistant to corrosion. In addition, CFRP tendons exhibit linear stress-strain relationship resulting in more accurate predictions for the tendon stress at ultimate. This hybrid system presents a challenge in developing an analytical model that could predict their behavior since the unbonded tendon is not bonded with the concrete. This investigation included the testing of 15 High Strength Concrete (HSC) beams prestressed with hybrid tendons. Results from the experimental study included number of cracks, load-deflection behavior, and strains in prestressing strand, reinforcing steel, and concrete. This study emphasizes the prediction of the ultimate stress of the unbonded tendon (fps) in unbonded or hybrid system for computing the ultimate moment resistance. Finite element modeling and analysis of various beams is performed. Based on a comparison of equations available in the literature as well as code provisions with the experimental results, a simplified prediction equation for predicting the stress in the unbonded tendons at ultimate is recommended.
Author: Kelvin John Watts
Publisher:
ISBN:
Category : Post-tensioned prestressed concrete
Languages : en
Pages :
Get Book Here
Book Description
Project is to study the behaviour of partially prestressed concrete beams with unbonded tendons. The main objective of the testing was to assess the amount of ductility that can be obtained from a post tensioned beam with unbonded tendon profile.
Author: FIB – International Federation for Structural Concrete
Publisher: FIB - Féd. Int. du Béton
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 1168
Get Book Here
Book Description
Author: Kimberly Waggle Kramer
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Currently, degradation of pretensioned prestressed reinforced concrete (PRC) bridge structures is a serious problem in the United States of America. Since 2000, the use of fiber-reinforced polymer (FRP) is well studied and has become an accepted method to rehabilitate concrete bridges. Design engineers use the ACI 440.2R-17 to determine strength requirements. Additionally, evaluating the deflection of strengthened PRC members is required during the restoration/strengthening design. ACI 440.2R-17 relies on ACI 318-19 for deflection calculations and limits prestressing from yielding under service load levels. This dissertation examines the application of the effective moment of inertia equation given in ACI 318-19 for the determination of deflection after cracking of PRC beams externally strengthened with carbon fiber reinforced polymers (CFRP). The results reported in this dissertation deal with the behavior of partially prestressed concrete beams strengthened with high strength composites. The three major parts discussed are experimental work, analytical investigations, and a parametric study. Experimental results obtained by other researchers were used to verify the results of the analytical procedures developed. The parametric study provides information on the moment-curvature and load-deflection behavior of strengthened pretensioned prestressed concrete flexural members externally strengthened with fiber-reinforced polymers that can be obtained for various concrete strengths, reinforcement ratios, and varying cross-sections. An analytical model was developed to predict the flexural rigidity of pretensioned, partially prestressed concrete beams that are externally strengthened with high strength composites. CFRP sheets were used for the derivation of equations. The proposed model is based on principles of mechanics and the sectional equations available for the analysis of partially prestressed beams. The model is applicable to the full range of prestressed concrete members covering partially and fully prestressed concrete, straight or harped strands, with or without supplemental mild-reinforcing steel, and varying loading conditions. The procedure can be used to generate the entire load-deflection response and through performing the moment-curvature analysis and estimation of stresses and strains in addition to computing the effective flexural stiffness of the strengthened prestressed member. Comparisons of experimental and analytical results show that deflection can be predicted with good accuracy using the developed modified effective moment of inertia equation. The parametric investigation was conducted on the effect of the basic variables namely, cross-section, concrete compressive strength, prestressing steel ratio, amount of carbon fibers, modulus of elasticity of prestressing steel-to-modulus of elasticity of CFRP ratio, modulus of elasticity of carbon fiber composite, spans, and shear span-to-span ratios. The goal of this investigation was conducted to understand the effect of CFRP strengthening to the flexural stiffness. Rectangular cross-sections with straight bonded prestressing tendons strengthened with 1 to 5 layers of unidirectional carbon sheets were analyzed in the parametric study. Lastly, the application of the proposed effective moment of inertia equation to bonded, pretensioned prestressed members, with harped strands depressed at midspan, externally strengthened with CFRP is examined in comparison with the experimental and analytical response curves.
Author: Philip Min Fui Yong
Publisher:
ISBN:
Category : Concrete slabs
Languages : en
Pages : 152
Get Book Here
Book Description
