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ANCHORAGE OF HIGH-STRENGTH REINFORCING BARS WITH STANDARD HOOKS By Ali Ajaam Submitted to the graduate degree program in Civil, Environmental, and Architectural Engineering and the Graduate Faculty of the University of Kansas in partial fulfilment of the requirements for the degree of Doctor of Philosophy Date Defended: April 3, 2017 ABSTRACT Hooked bars are often used to anchor reinforcing steel where concrete dimensions are not sufficient to provide the required development length for straight reinforcement, such as in external beam-column joints. The purpose of this study is to expand the understanding of the behavior of hooked bars in high-strength concrete and to develop design guidelines allowing for the use of high-strength reinforcing steel and high-strength concrete. In this study, 122 simulated beam-column joints were tested as a continuation of previous work at the University of Kansas. The test parameters included bar size (No. 5, No. 8 and No. 11), hook bend angle (90° or 180°), embedment length (5.5 to 23.5 in.), amount of confining reinforcement within the joint (no confining reinforcement to nine No. 3 hoops), location of the hooked bar with respect to member depth, hooked bar stresses (22,800 to 138,800 psi), concrete compressive strength (4,490 to 14,050 psi), center-to-center spacing between hooked bars (2 to 11.8db), number of hooked bars (2, 3, 4, or 6), arrangement of hooked bars (one or two layers), and ratios of beam effective depth to embedment length (0.6 to 2.13). Some specimens contained strain gauges mounted along the straight portion of the hooked bars and on the confining reinforcement within the joint rejoin. Test results from this study, along with test results from earlier work covering specimens without and with confining reinforcement, concrete compressive strengths between 2,570 and 16,510 psi, and bars stresses at anchorage failure ranging from 22,800 and 144,100 psi, were used to develop descriptive equations for the anchorage strength of hooked bars. The results of this study show that the current Code provisions overestimate the contribution of the concrete compressive strength and the bar size on the anchorage strength of hooked bars. The incorporation of the modification factors for cover and confining reinforcement in the provisions in the ACI Building Code (ACI 318-14) produces an unconservative estimation of anchorage strength of hooked bars, particularly with large hooked bars and closely-spaced hooked bars (hooked bars with center-to-center spacing less than 6db). Closely-spaced hooked bars exhibit less anchorage strength than widely-spaced hooked bars. The reduction in anchorage strength of closely-spaced hooked bars is a function of both the spacing between hooked bars and the amount of confining reinforcement. Both the hooks and the straight portion of hooked bars contribute to anchorage strength. The anchorage strength of staggered hooked bars can berepresented by considering the minimum spacing between the bars. Hooked bars anchored in beam-column joints with ratio of beam effective depth to embedment length greater than 1.5 exhibit low anchorage strengths compared to hooked bars with a ration below 1.5. These observations are used to develop proposed Code provisions for the development length of reinforcing bars anchored with standard hooks. The proposed provisions provide a higher level of reliability than current provisions and can be used for reinforcing steels with yield strengths up to 120,000 psi and concretes with compressive strengths up to 16,000 psi. Keywords: anchorage , beam-column joints, bond and development, concrete, high-strength concrete, high-strength steel, hooks, closely-spaced hooks, staggered-hooks, reinforcement, reinforcement strain منبع Ajaam_ku_0099D_15173_DATA_1.pdf

Summary of Concrete Workability Test Methods University of Texas RESEARCH REPORT ICAR –105-1 Sponsored by the Aggregates Foundation for Technology, Research and Education Eric P. Koehler University of Texas at Austin Austin, TX David W. Fowler University of Texas at Austin Austin, TX فایل پی دی اف در 93 صفحه منبع @Civilbest ICAR 105-1.pdf

Concrete Pavement : Selection of Concrete Materials Jerry L. Larson فایل پی دی اف در 40 اسلاید منبع @Civilbest,_s81_20Jerry_20Larson.pdf

PRECAST CONCRETE PAVEMENT TECHNOLOGY By Shiraz Tayabji, Ph.D., P.E. Senior Consultant Fugro Consultants, Inc. Columbia, Maryland منبع PPCP65 Desk Scan (PCPS) (26Nov2010).pdf.pdf

Advances in Concrete Slab Technology Proceedings of the International Conference on Concrete Slabs Held at Dundee University, 3–6 April 1979 منبع Advances_in_Concrete_Slab_Technology.pdf

Control of Deflection in Concrete Structures ACI 435R-95 Reported by ACI Committee 435 This report presents a consolidated treatment of initial and time-dependent deflection of reinforced and prestressed concrete elements such as simple and continuous beams and one-way and two-way slab systems. It presents the state of the art in practice on deflection as well as analytical methods for computer use in deflection evaluation. The introductory chapter and four main chapters are relatively independent in content. Topics include “Deflection of Reinforced Concrete One-way Flexural Members,” “Deflection of Two-way Slab Systems,” and “Reducing Deflection of Concrete Members.” One or two detailed computational examples for evaluating the deflection of beams and two-way action slabs and plates are given at the end of Chapters 2, 3, and 4. These computations are in accordance with the current ACI- or PCI-accepted methods of design for deflection. Keywords: beams; camber; code; concrete; compressive strength; cracking; creep; curvature; deflection; high-strength concrete; loss of prestress; modulus of rupture; moments of inertia; plates; prestressing; pretensioned; post-tensioned; reducing deflection; reinforcement; serviceability; download ACI435.pdf

Cement and Concrete Nanoscience and Nanotechnology Laila Raki *, James Beaudoin, Rouhollah Alizadeh, Jon Makar and Taijiro Sato National Research Council Canada, Institute for Research in Construction / 1200 Montreal Road, Bldg M-20, Ottawa, Ontario K1A 0R6, Canada; E-Mails: jim.beaudoin@nrc-cnrc.gc.ca (J.B.); rouhollah.alizadeh@nrc-cnrc.gc.ca (R.A.); jon.makar@nrc-cnrc.gc.ca (J.M.); taijiro.sato@nrc-cnrc.gc.ca (T.S.) * Author to whom correspondence should be addressed; E-Mail: laila.raki@nrc-cnrc.gc.ca; Tel. (613) 991-2612; Fax: (613) 954-5984. Received: 24 December 2009; in revised form: 27 January 2010 / Accepted: 28 January 2010 / Published: 3 February 2010 Abstract: Concrete science is a multidisciplinary area of research where nanotechnology potentially offers the opportunity to enhance the understanding of concrete behavior, to engineer its properties and to lower production and ecological cost of construction materials. Recent work at the National Research Council Canada in the area of concrete materials research has shown the potential of improving concrete properties by modifying the structure of cement hydrates, addition of nanoparticles and nanotubes and controlling the delivery of admixtures. This article will focus on a review of these innovative achievements. Keywords: nanotechnology; concrete; cement; C-S-H; controlled release; carbon nanotubes; nanoparticles به نقل از کانال تلگرام civilca دانلود از پیوست نانو در سیمان و بتن.pdf

DIRECT DISPLACEMENT-BASED SEISMIC DESIGN OF CONCRETE BUILDINGS MJN Priestley, MJ Kowalsky - Bulletin of the New Zealand National …, 2000 - cat.inist.fr Abstract A seismic design procedure is developed to enable concrete buildings to be designed to achieve a specified acceptable level of damage under the design earthquake. The acceptable limit is defined as a displacement profile related to limit material strains or code specified drift limits. In this procedure, the elastic properties, including initial stiffness, strength and period, are the end product of the design rather than the starting point. It is shown that the procedure is simple to apply, and results in significant differences from the more conventional force-based procedure. Designs for multi-storey frame and wall buildings are presented, and target displacements are compared with results from inelastic time-history analysis. Source 2000, vol. 33, no4, pp. 421-444 (14 ref.) Publisher New Zealand National Society for Earthquake Engineering, Wellington, NOUVELLE-ZELANDE (1974-1998) 33(4)0421.pdf

ASSESSMENT OF MECHANICAL PROPERTIES OF CONCRETE CONTAINING GRANITE SLURRY WASTE (TECHNICAL NOTE) S. Sharma, T. Gupta and R. K. Sharma Abstract The granite stone is most widely used in the construction and it generates granite slurry through cutting and polishing of the stone. Granite slurry is waste material consisting of very fine powder and creating disposal and environmental problems worldwide today. Disposal of granite waste leads to health hazards like respiratory and allergy problems to the people around. It also causes the pollution of air and water. Concrete is most widely used construction material and innovation in ingredient material (cement and coarse aggregate) is urgently needed. The replacement of natural resources in the production of cement is an important issue in the present construction scenario. Also, the cement industry is one of the principal producers of carbon dioxides. Utilization of granite slurry waste in concrete can solve many problems related to waste generation, reduction in the consumption of natural resources and CO2 emission. Systematic experimental study has been carried out using granite slurry waste in place of cement at various replacement levels. This study has been carried out for w/c 0.5 and 0.4. Specimens have been cast to perform compressive strength test and flexural strength test. It has been shown that inclusion of granite slurry modifies the compressive strength and maximum strength has been obtained depending upon replacement level and w/c ratio. Flexural strength is also influenced by the addition of granite slurry waste in a similar way. These replacement studies demonstrate that the granite slurry concrete will be economically cheaper and will be more sustainable. Keywords Concrete, granite slurry waste, compressive strength, flexural strength چکیده سنگ گرانیت، سنگ مرمر به طور گسترده ای در ساخت و ساز استفاده می شود و آن را تولید دوغاب گرانیت، سنگ مرمر از طریق برش و صیقل سنگ. دوغاب گرانیت مواد زائد متشکل از پودر بسیار و ایجاد مشکلات زیست محیطی دفع و در سراسر جهان امروز است. دفع زباله گرانیت منجر به خطرات بهداشتی مانند مشکلات تنفسی و آلرژی به مردم در اطراف. همچنین باعث می شود که آلودگی هوا و آب است.بتن به طور گسترده استفاده مواد ساخت و ساز و نوآوری در مواد تشکیل دهنده (سیمان و مصالح سنگی درشت دانه) است ضروری و مورد نیاز. جایگزینی منابع طبیعی در تولید سیمان به یک مسئله مهم در سناریوی ساخت و ساز موجود است. همچنین، صنعت سیمان یکی از تولید کنندگان اصلی دی اکسید کربن است. استفاده از گرانیت، سنگ مرمر زباله دوغاب در بتن می تواند بسیاری از مشکلات مربوط به هدر نسل، کاهش در مصرف منابع طبیعی و انتشار CO2 را حل کند.مطالعه تجربی سیستماتیک شده است با استفاده از گرانیت، سنگ مرمر زباله دوغاب سیمان در محل در سطوح مختلف جایگزینی انجام شده است. این مطالعه برای W / C 0.5 و 0.4 انجام شده است. نمونه ها ریخته شده به منظور انجام آزمون مقاومت فشاری و خمشی آزمون مقاومت. نشان داده شده است که گنجاندن دوغاب گرانیت تغییر مقاومت فشاری و حداکثر قدرت است بسته به سطح جایگزینی و نسبت W / C بدست آمده است. استحکام خمشی نیز علاوه بر این از زباله دوغاب گرانیت، سنگ مرمر در یک روش مشابه تحت تاثیر قرار. این مطالعات نشان می دهد که جایگزینی بتن دوغاب گرانیت، سنگ مرمر از لحاظ اقتصادی ارزان تر خواهد شد و بیشتر پایدار است.سنگ گرانیت، سنگ مرمر به طور گسترده ای در ساخت و ساز استفاده می شود و آن را تولید دوغاب گرانیت، سنگ مرمر از طریق برش و صیقل سنگ. دوغاب گرانیت مواد زائد متشکل از پودر بسیار و ایجاد مشکلات زیست محیطی دفع و در سراسر جهان امروز است. دفع زباله گرانیت منجر به خطرات بهداشتی مانند مشکلات تنفسی و آلرژی به مردم در اطراف. همچنین باعث می شود که آلودگی هوا و آب است.بتن به طور گسترده استفاده مواد ساخت و ساز و نوآوری در مواد تشکیل دهنده (سیمان و مصالح سنگی درشت دانه) است ضروری و مورد نیاز. جایگزینی منابع طبیعی در تولید سیمان به یک مسئله مهم در سناریوی ساخت و ساز موجود است. همچنین، صنعت سیمان یکی از تولید کنندگان اصلی دی اکسید کربن است. استفاده از گرانیت، سنگ مرمر زباله دوغاب در بتن می تواند بسیاری از مشکلات مربوط به هدر نسل، کاهش در مصرف منابع طبیعی و انتشار CO2 را حل کند.مطالعه تجربی سیستماتیک شده است با استفاده از گرانیت، سنگ مرمر زباله دوغاب سیمان در محل در سطوح مختلف جایگزینی انجام شده است. این مطالعه برای W / C 0.5 و 0.4 انجام شده است. نمونه ها ریخته شده به منظور انجام آزمون مقاومت فشاری و خمشی آزمون مقاومت. نشان داده شده است که گنجاندن دوغاب گرانیت تغییر مقاومت فشاری و حداکثر قدرت است بسته به سطح جایگزینی و نسبت W / C بدست آمده است. استحکام خمشی نیز علاوه بر این از زباله دوغاب گرانیت، سنگ مرمر در یک روش مشابه تحت تاثیر قرار. این مطالعات نشان می دهد که جایگزینی بتن دوغاب گرانیت، سنگ مرمر از لحاظ اقتصادی ارزان تر خواهد شد و بیشتر پایدار است. 16-109.pdf

Strengthening Demand of Columns in A RCC Structure Due To Construction of An Additional Storey Mohd Irfan, D r . Abhay Sharma, Dr. Vivek G arg PG Scholar, Associate Professor Assistant Profe ssor Civil Engineering Department Civil Engineering Department Civil Engineering Department NIT Bhopal, Madhya Pradesh, India. NIT Bhopal, Madhya Pradesh, India NIT Bhopal, Madhya Pradesh, India .Abstract - Generally the people construct the structure to fulfill their current needs but with the passage of time they realize that their demands have increased and there is a need for the addition/alteration of the current structure. This demand can be fulfilled by constructing a new storey. However, provision for additional load due to the new construction over existing structure was not made in the structural design of the old structure. Therefore, the construction of new storey requires the strengthening of the old structure. The present study investigates the structural behaviour of an RC frame under the additional load in the form of a new storey. The analysis of existing structure (two storey) and proposed structure (one additional storey constructed over existing two storey structure) is performed by using structural analysis software i.e. STAAD Pro. The analysis results of existing and proposed structure are compared to evaluate the increase in structural forces due to the construction of a new storey. The results indicates that the significant increase is found in the axial force and bending moment in columns. The weak and deficient columns are identified and strengthened for the additional loads and additional moments. The strengthening of columns is done by jacketing of the columns using four steel angles at corners, confined with the help of batten plates placed at equal spacing along the length of the column. Keywords- Concrete; Steel; Jacketing; Strengthening. منبع : کانال تلگرام بهسازی و مقاوم سازی سازه ها [Hidden Content] V3I8_IJERTV3IS080489.pdf

Cost Implication of Mitigating the Effect of Clay/Silt Content of Sand on Concrete Compressive Strength Oiginal Article, B25 Olanitori LM. J. Civil Eng. Urban. 2(4): 143-148. 2012. ABSTRACT: In Nigeria, reinforced concrete is one of the major building materials been used in the construction of buildings. In the specification of concrete, prescribed mix is normally used. However, tests carried out on different batches of concrete produced, using prescribed mix 1:2:4 of concrete show that the concrete did not acquire the 20N/mm2 expected strength at the age of 28 days. Depending on the type of sand used for the production of the concrete, the acquired strength after 28 days is between 25% and 60% of the expected strength. This reduction in strength will ultimately affect the functionality and durability of structure constructed from such concrete. To mitigate the effect of clay/silt content of sand, the sand can be washed free of clay/silt or the cement is increased in proportion to the percentage content of clay/silt in the sand. Since the mitigation of the clay/silt content of sand on concrete strength comes with extra cost, there is need to determine this cost in other to be able to build effective and safe structures. The author evaluates the cost implication of mitigating this reduction effect of the type of sand used on concrete strength. The extra cost incurred in the production of 1m3 of concrete (using mix ratio 1:2:4) in terms of washing the sand free of clay/silt is 22.5%, while that of cement increment is between 2.22% and 27.75% depending on the percentage of clay/silt content of sand. Mathematical models, which can be used to estimate the cost implication of this mitigation, are derived. Keywords:Reinforcement, Concrete, Sand, Silt, Strength منبع: [Hidden Content] دانلود: [Hidden Content],%20B25.pdf JCEU, B25.pdf

Material-Based Ultimate Moment of Resistance of a Rectangular Concrete Section Original Article, B23 Joseph Afolayan O, Stephen Alabi A, Lekan Olanitori M. J. Civil Eng. Urban. 2(4): 131-135. 2012. ABSTRACT:The incessant collapse of buildings in Nigeria in recent years has been a major concern. This paper addresses one of the major possible causes of building collapse. The minimum compressive strength of concrete using pit-sand as a fine aggregate in Akure, Nigeria was statistically estimated. On the basis of the estimated nominal concrete strength, an implied ultimate moment of resistance of singly reinforced concrete rectangular sections is proposed. The proposal shows that the recommended resistance of concrete given by BS8110 (1997) may be reduced by as much as 50% in order to accommodate the minimum concrete strength for a 1:2:4 mix. A numerical design example based on the proposal showed the necessity of additional compressive reinforcement to justify the use of the current BS 8110 (1997) requirement if Akure pit-sand must be used as fine aggregate. Keywords:Pit-sand, Concrete, Compressive Strength, implied Ultimate Moment of Resistance. منبع: [Hidden Content] دانلود: [Hidden Content],%20B23.pdf JCEU, B23.pdf