[PDF] Analytical And Experimental Evaluation Of Bond Strength Of Tension Lap Splices In High Strength Concrete Wrapped With Fiber Reinforced Polymer eBook

Author : Ahmad Ali Rteil
Publisher :
Page : 306 pages
File Size : 25,9 MB
Release : 2002
Category :
ISBN :

GET BOOK

The deterioration of reinforced concrete structures is increasingly becoming a serious problem facing the infrastructure worldwide. To prolong the service life of existing structures, fiber reinforced polymer (FRP) sheets are being used. On the other hand, research reported in the literature indicates that a mechanism should exists which would confine the tension lap splices in high strength concrete (HSC) in order to have a more ductile failure and to increase the capacity of the lap splice. The main objective of this research is to assess the effect of FRP wraps in improving the serviceability and ultimate response of bond-critical regions in reinforced concrete members. The lack of research reported in the literature on the effect of the FRP wraps on bond strength makes this study significant. Moreover, the research will provide important design information that facilitates the introduction of FRP into design codes and encourage the use of this new technology. To meet the objective, 10 full-scale high strength concrete beam specimen were tested. Each beam was designed with 20-mm bars spliced in a constant moment region at midspan. The variables were: FRP type (glass or carbon), number of layers of FRP (1 or 2), and the configuration of FRP wraps placed in the splice region. Results of the study indicated that FRP wraps have similar effects to those of steel fibers and transverse steel reinforcement in confining the splices in HSC beam specimen. The brittle mode of failure is modified to a more ductile one. More bar lugs along the spliced bars are allowed to participate in the stress transfer between steel and concrete, and the average splitting bond strength is increased. Finally, a new index, Ktr, f, accounting for the presence and amount of FRP confining tension lap splices in HSC beams was proposed.

Author : Michael Grantham
Publisher : CRC Press
Page : 872 pages
File Size : 33,52 MB
Release : 2011-09-08
Category : Technology & Engineering
ISBN : 0415616220

GET BOOK

The Concrete Solutions series of International Conferences on Concrete Repair began in 2003, with a conference held in St. Malo, France in association with INSA Rennes, followed by the second conference in 2006 ( with INSA again, at St. Malo, France), and the third conference in 2009 (in Padova and Venice, in association with the University of Padova). Now in 2011, the event is being held in Dresden in Germany and has brought together some 112 papers from 33 countries. Whereas electrochemical repair tended to dominate the papers in earlier years, new developments in structural strengthening with composites have been an increasingly important topic, with a quarter of the papers now focusing on this area. New techniques involving Near Surface Mounted (NSM) carbon fibre rods, strain hardening composites, and new techniques involving the well established carbon fibre and polyimide wrapping and strengthening systems are presented. Seventeen papers concentrate on case studies which are all-important in such conferences, to learn about what works (and what doesn’t work) on real structures. Thirteen papers are devoted to new developments in Non-Destructive Testing (NDT). Other topics include service life modelling, fire damage, surface protection methods and coatings, patch repair, general repair techniques and whole life costing. This book is essential reading for anyone engaged in the concrete repair field, from engineers, to academics and students and also to clients, who, as the end user, are ultimately responsible for funding these projects and making those difficult decisions about which system or method to use.

Author : Michael Grantham
Publisher : CRC Press
Page : 834 pages
File Size : 43,9 MB
Release : 2014-08-18
Category : Technology & Engineering
ISBN : 1315737310

GET BOOK

The Concrete Solutions series of International Conferences on Concrete Repair began in 2003 with a conference held in St. Malo, France in association with INSA Rennes. Subsequent conferences have seen us partnering with the University of Padua in 2009 and with TU Dresden in 2011. This conference is being held for the first time in the UK, in associ

Author : Omar Samir Gharzuddine
Publisher :
Page : 200 pages
File Size : 17,81 MB
Release : 2005
Category :
ISBN :

GET BOOK

With the more frequent use of FRC in earthquake resistant structures as a means for improving energy absorption and dissipation capacity, understanding the infl uence of steel fiber reinforcement on the bond strength between steel bars and c oncrete becomes of particular interest. While several experimental and analytical studies have concentrated on the bond characteristics under static load conditions, data on the bond stress characteri stics of steel bars in plain concrete or concrete applied with steel fiber reinf orcement is still very limited, particularly when the mode of bond failure is by splitting. This shortage of data makes it difficult at present to establish gen eral recommendations for computing the minimum volume of steel-fiber reinforceme nt needed to improve the seismic performance of reinforced beams, taking into ac count the bond parameters of the beam spliced reinforcement and the distribution of this reinforcement in the section. Experimentally investigating the bond cha racteristics of reinforcing steel bars embedded in FRC under seismic loading for better understanding of the mechanism by which fiber reinforcement improves the bond strength and seismic performance of spliced bars in tension constitutes th e primary objective of this proposed investigation. Also based on the results of this investigation, the main parameters that influence the response will be eva luated and discussed, and existing models for predicting the bond strength will be further validated or refined. To meet the objectives, 12 full-scale normal and high strength concrete beam spe cimens were tested. Each beam was designed with bar splices (20db) placed in a c onstant moment region at midspan. No transverse reinforcement will used in the s plice region. The design variables were the bar size (20 and 25 mm), ratio of co ncrete cover to bar diameter (c/db of 2.0 and 1.4), and the volume of fraction o f fibers (Vf = 0.0%, 0.5%, 1.0%, 1.5%). The test results indicated that the use of steel fibers in the splice region inc reased the ultimate load capacity, bond strength, reduced bond deterioration, im proved ductility, increased energy absorption capacity and also verified in part the equation proposed by Harajli and Mabsout2000 that accounts for the increase in bond strength of beams due to the presence of fibers.

Author : American Society of Civil Engineers
Publisher :
Page : 1132 pages
File Size : 44,94 MB
Release : 2004
Category : Civil engineering
ISBN :

GET BOOK

Vols. 29-30 contain papers of the International Engineering Congress, Chicago, 1893; v. 54, pts. A-F, papers of the International Engineering Congress, St. Louis, 1904.

Author : Ghaida' Khaled Joumaa
Publisher :
Page : 330 pages
File Size : 32,31 MB
Release : 2000
Category :
ISBN :

GET BOOK

To meet the objectives, 12 full-scale high strength concrete beam specimens were tested Each beam was designed with bars spliced in a constant moment region at midspan. The variables were bar size 20, 25, or 32 mm, and the amount of steel fiber reinforcement added in the splice region during casting: Vf = 0 5, 0 5, 1.0, or 2 0 %--The test results indicated that the use of steel fibers in the splice region increased the bond strength and the ductility of the mode of failure of the beam--specimens The increase in bond strength with high fiber content exceeded 3 square root fc, the maximum increase in bond strength of a reinforced concrete beam that could be achieved by using transverse reinforcement in the splice region.

Author : Eric Jacques
Publisher :
Page : pages
File Size : 26,20 MB
Release : 2016
Category :
ISBN :

GET BOOK

Despite the on-going intensity of research in the field of protective structural design, one topic that has been largely ignored in the literature is the effect of high strain rates on the bond between reinforcing steel and the surrounding concrete. Therefore, a comprehensive research program was undertaken to establish the effect of high strain rates on reinforced concrete bond. The experimental research consisted of the construction and testing of fourteen flexural beam-end bond specimens and twenty-five lap-spliced reinforced concrete beams. The physical and material properties of the specimens were selected based on a range of design parameters known to significantly influence bond strength. In order to establish a baseline for comparison, approximately half of the total number of specimens were subjected to static testing, while the remainder were subjected to dynamic loading generated using a shock tube. The strain rates generated using the shock tube were consistent with those obtained for mid- and far-field explosive detonation. Results of the beam-end and lap splice beam tests showed that the flexural behaviour of reinforced concrete was significantly stronger and stiffer when subjected to dynamic loading. Furthermore, the high strain rate bond strength was always greater than the corresponding low strain rate values, yielding an average dynamic increase factor (DIF) applied to ultimate bond strength of 1.28. Analysis of the low and high strain rate test results led to the development of empirical expressions describing the observed strain rate sensitivity of reinforced concrete bond for spliced and developed bars with and without transverse reinforcement. The predictive accuracy of the proposed DIF expressions was assessed against the experimental results and data from the literature. It was found that the dynamic bond strength of reinforced concrete can be predicted with reasonably good accuracy and that the proposed DIF expressions can be used for analysis and design of protective structures. An analytical method was also developed to predict the flexural load-deformation behaviour of reinforced concrete members containing tension lap splices. The analysis incorporated the effect of reinforcement slip through the use of pseudo-material stress-strain relationships, in addition to giving consideration to the effect of high strain rates on bond-slip characteristics and on the material properties of concrete and steel. A comparison of the analytical predictions with experimental data demonstrated that the proposed analysis technique can reasonably predict the flexural response of beams with tension lap splices. The results also demonstrated that the model is equally applicable for use at low- and high-strain rates, such as those generated during blast and impact.

Author : Mouhamad Youssef Mansour
Publisher :
Page : 214 pages
File Size : 47,50 MB
Release : 1994
Category : Concrete construction
ISBN :

GET BOOK

A tension lap splice is a common and necessary detail in reinforced concrete construction. A noncontact lap splice also called spaced splice, is a structural detail in reinforced concrete that provides continuity to the reinforcement by overlapping the ends of the steel without the bars touching. The subject of bar spacing in tension lap splices is addressed in the ACI Building Code and Commentary. Section 12.14.2.3 of the code states that "bars spliced by noncontact lap splices in flexural members shall not be spaced transversely farther than one-fifth the required lap splice, nor 6inches". The current provision limiting the spacing of noncontact lap splices was based on experience as well as on limited research performed before 1971. The objective of this study is to perform wider scope research on slab specimens to check the requirements of the ACI Building Code and provide recommendations. Slab specimens were designed to include three bars in tension, spliced at the center of the span. The splice length was selected so that the bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. The slabs were loaded in positive bending with the splice in a constant moment region. The materials used in the experimental program were typical of those used in current construction practices. The main variable was the center-to-center spacings of bars in each splice.

Author : fib Fédération internationale du béton
Publisher : fib Fédération internationale du béton
Page : 448 pages
File Size : 46,9 MB
Release : 2000-01-01
Category : Technology & Engineering
ISBN : 9782883940505

GET BOOK

"In 1993, the CEB Commission 2 Material and Behavior Modelling established the Task Group 2.5 Bond Models. It's terms of reference were ... to write a state-of-art report concerning bond of reinforcement in concrete and later recommend how the knowledge could be applied in practice (Model Code like text proposal)... {This work} covers the first part ... the state-of-art report."--Pref.