It improves axial and shear strength of column and major strengthening of foundation may be avoided. This can be made by longitudinal steel bars and additional concrete around an existing column or placing a jacket around the column. This method has been particul arly successful for jacketing columns. Faculty of engineering, al azhar university nasr city, cairo, egypt abstract in the present study, the steel jacketing technique with variable vertical angles size. Commentary 1 the fundamentals of ordinary design and construction of concrete structures are covered in the standard. Concrete jacket construction detail effectiveness when. Jacketing of reinforced concrete columns with steel longitudinal angles and transversal plates is a suitable method for retrofitting columns. In design process we must take two important points in considerations. Global retrofitting the retrofitting in which we use to repair the whole structure is called global retrofitting. Retrofitting comparative study of rc jacketing and frp wrapping article pdf available in international journal of civil engineering and technology 75. Investigating an effective method for strengthening structural elements. Introduction to repair and strengthening of reinforced concrete structures 1. Three months later, the columns were strengthened by rc jacketing after their surface had been prepared considering different techniques.
What is reinforced concrete jacketing and retrofitting. Retrofit of reinforced concrete columns the ohio state university. Strengthening column using micro concrete jacketing remove entire plaster to reach parent concrete surface if the column is plaster. An aci provisional standard american concrete institute. The common practice to prepare the interface is empirically.
An experimental study of reinforced concrete, rc, columns strengthened using a steel jacketing technique was conducted. Strengthening column using micro concrete jacketing. Concrete jacketing is a commonly used method to retrofit or strengthen existing columns for axial loads. At first, 45 concrete cylinders were fabricated with varying design compressive strengths of 21. Widening and strengthening of existing foundations may be carried out by constructing a concrete jacket to the existing footings. The properties of composite materials, such as high strength, low thickness, and low weight, allow them to be applied on a construction site as confinement. All test records were automatically saved on computer file for further data.
The development of these methods was a necessity due to different causes, such as inadequate maintenance, overloading of the reinforced concrete member, corrosion of the steel reinforcement and other different situations that appeared in time. Proceedings of the 4th world congress on civil, structural, and environmental engineering csee19 rome, italy april 79, 2019 paper no. Pdf reinforced concrete rc jacketing is most frequently used to strengthen columns. This technique is used on vertical surfaces such as walls, columns and other. Behaviour of rcc column strengthened using steel jacketing. In the following paragraphs, this method is assessed according to different aspects. Jacketing is the most popularly used method for strengthening of building columns. Four full scale beams were first loaded to certain levels of ultimate capacity 0, 60%, 77%, 100% of failure load. Jacketing is one of the most frequently used techniques to strengthen reinforced concrete rc columns. Strength and ductility of rc jacketed columns queens university.
Reinforced concrete rc jacketing is a common method for retrofitting existing columns with poor structural performance. Effectiveness of various methods of jacketing for rc beams. The overlaying and jacketing construction method is a retrofitting method in which concrete sections are added and corresponds to 2 overlaying construction method and 3 jacketing construction method. Strengthening of reinforced concrete rc beams is required due to design errors, deficient concrete production, bad execution processes, damage due to earthquake, accidents such as collisions, fire, explosions and situations involving changes in the functionality of the structure etc. These draft guidelines are designed to complement these documents and indicate. Volumes are subsequently converted to design weights, which then become the basis for actual production of concrete from the plant. The increase in shear strength and confinement, and improved lapsplice performance without creating a significant. With this method, axial strength, bending strength, and stiffness of the original column are increased. Then, after formation of cracks or failure, they were repaired by reinforced concrete jacketing method and tested again up to failure. Behavior of reinforced concrete columns strengthened by steel jacket. Paper open access strengthening method of concrete. The size of the jacket and the number and diameter of the steel bars used in the jacketing process depend on the structural analysis that was made to the column. Column jacketing is a way of increasing the cross section of column to enable it to take additional load or moment. Retrofitting existing concrete elements by method of jacketing.
Effect of different parameters of uconcrete jacketing on. Common methods for strengthening columns include concrete jacketing, fiber. The preplaced aggregate method can be used for most repair applications that call for a thickness or depth greater than 2 in. Prior to commencement of the work, the contractor shall submit for approval, the make, model and manufacturer of each piece of equipment intended for. This paper introduces a new steel jacketing method for reinforced concrete rc columns with lap splice and evaluates its performance by a series of axial tests of concrete cylinders. Concrete jacketing is needed to increase bearing load capacity following a modification of the structural design or to restore structural design integrity due to a failure in structural member.
Strength and ductility are substantially improved regardless of the method used to fix the jacket to the concrete. Retrofitting of existing rcc buildings by method of jacketing. Jacketing and collars for concrete column beam strengthening. This technique is used on vertical surfaces such as walls, columns and other combinations such as beam sides and. Jacketing has been considered as one of the important methods for strengthening and repairing of rc beams.
Jacketing consists of added concrete with longitudinal and transverse reinforcement around the existing column. Repair and strengthening of reinforced concrete structures. Three alternative methods of concrete jacketing are investigated and results are compared with results from an original unstrengthened specimen and a monolithic specimen. Solutions for bond improving of reinforced concrete. Ijett steel jacketing technique used in strengthening. Concrete repair manual 14 txdot 012019 chapter 1 introduction section 2 using the concrete repair manual section 2 using the concrete repair manual when developing repair or rehabi litation plans, the engineer shoul d specifically include which sections of this manual will be enforced. Jacketing of beam it consist of added concrete with longitudinal and transverse reinforcement around the existing beam.
The aim of this paper is to explain a method on how to strengthen a concrete building structure that people can uselearn as a better way to cut potential cost and save time. Proportioning concrete by the absolute volume method involves calculating the volume of each ingredient and its contribution to making one yd3 or 27 ft3 of concrete. Rolled steel sections jacketingembedded inside concrete. Research article materials and jacketing technique. Pdf reinforced concrete jacketing interface influence on. This study aimed at investigating the effectiveness of strengthening the entire height of downscaled square rc columns by applying forta ferro polypropylene fibrous ultra high performance self compacting concrete fibrous uhpscc as a jacketing material.
Methods of increasing bond between old and new concrete are analysed. Repair and strengthening of reinforced concrete beams. Each one of these methods has its difficulties regarding the new construction forms needed and the modification in. There are various methods of repair and retrofitting for earthquake damaged masonry. The primary methods compared are reinforced concrete jacketing and. The most common types of jackets are steel jacket, reinforced concrete jacket, fibre reinforced polymer composite jacket, jacket with high tension materials like carbon fibre, glass fibre etc. Pdf reinforced concrete jacketing interface influence. It shows advantages particularly in seismic retrofitting, since it enhances strength, ductility and consequently the energy. Retrofitting existing concrete elements by method of jacketing solutions horse construction business range tend to all over the world and service for thousands clients with products, technical,construction specialized guidance, and we witness the chinese reinfocing brands togther with them.
Jacketing is particularly used for the repair of deteriorated columns, piers, and piles and may easily be employed in underwater applications. It improves axial and shear strength of column and major strengthening of. Solutions for bond improving of reinforced concrete columns jacketing cosmin enuica, corneliu bob, sorin dan, catalin badea, aurelian gruin. It is one of the techniques used to improve or restore capacity of reinforced concrete column. Concrete jacketing is needed to increase bearing load capacity following a modification of the structural design or to restore structural design integrity due to a failure in the structural member. Pdf retrofitting comparative study of rc jacketing and. An experienced contractor working under the guidance of a qualified engineer is the best choice for repairs using this method. Strengthening reinforced concrete columns by jacketing. Extra floors are added to a building which were not part of initial design 2. Prestressed concrete jacketing construction method. The jacketing method comprised of four steel vertical points introduced at the sides of the section joined by even steel lashes keeping the segment remotely. Strengthening and repair of reinforced concrete columns by.
The method is applicable for protecting concrete, steel, and timber sections against further deterioration and for strengthening. Confinement of concrete columns with composite sheets showed many advantages in comparison to other confinement methods. In traditional reinforced concrete jacketing, the section of the column is enlarged by casting a new reinforced concrete mortar section over a part or the entire length of the column. It is well known that the success of this procedure is dependent on. The installation procedures were summarized and the advantages, shortcomings, and considerations of each method were also discussed in the thesis. Aci structural journal technical paper following previous studies, the authors describe an experimental study performed to analyze the influence of the interface treatment on the seismic behavior of columns strengthened by reinforced concrete rc jacketing to increase their ultimate bending moment. With this method, axial strength, bending strength, and. Placing prestressing wires and prestressing stranded steel wires in place of lateral ties around the periphery of existing member sections and using mortar and concrete to bond them in order to reinforce the structure. The strengthening method explained in this paper is steel jacketing, providing a case study of this method in the extension of a restaurant located in medan, indonesia. Jacketing is a technique used to increase the strength of existing structural members e. Jacketing is a widely accepted method for retrofitting rc columns. Repair and rehabilitation structural rehabilitation of. Now by tapping with a light hammer, identify of loose concrete portions are present. Steel jacketing technique used in strengthening reinforced concrete rectangular columns under eccentricity for practical design applications ezzeldeen, h.
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