A second video shows how the shear resistance of the slab and its deflection are checked. The first reinforced concrete design manual formerly titled aci design handbook was developed in. Concrete slab rest ing on grade cont aining steel reinforcement which consists of either a welded wire fabric or deformed reinforcing steel bars. Refer to aci 223 for procedures for the design and construction of shrinkagecompensating concrete slabsonground. For slab onground floors it provides an understanding of the footing slab selection, design, detailing and construction requirements contained in as 2870 and. They can be insulated, both underneath and on the edges. Reinforced concrete sk 33 section through slab showing stress due to moment. The slab has to carry a distributed permanent action of 1.
In order to simplify the design of the slab and columns, there was an assumption that shear walls would. Tolerances for the floors placed on these suspended systems are often misunderstood. Suspended slab cracking structural engineering general. Direct design method ddm for slab systems with or without beams loaded only by gravity loads and. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Sci p300, composite slabs and beams using steel decking. Structural redesign two way slab drop panels my redesign of fordham place will comprise of a 9 flat slab with 5. Tm 580912 concrete floor slabs on grade subjected to heavy. The posttensioning institute pti design manual6 gives recommended spantothickness ratios for slabs and. Floor width must be greater than zero for all loads.
The assembly is designed for seismic zone 2 and may be used for structures up to 8 storeys. There are 16 different types of slabs in construction. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. How to design concrete structures using eurocode 2. The advantage of a suspended reinforced concrete slab is that it is possible to get high strength, but at the same time keep the weight low.
Reinforced concrete slab design using the empirical method bridgesight solutions for the aashto lrfd bridge design specifications bridgesight software tm creators of effective and reliable solutions for the worlds bridge engineers. Sep 03, 2011 reinforced concrete sk 33 section through slab showing stress due to moment. For a suspended slab, the formwork is shaped like a tray, often supported by a temporary scaffold until the concrete sets. If its a cip concrete slab, then they sound much worse. In this paper a design method developed for structural design of this slab system is presented. However, the procedure for the lateral distribution of the moments is the same for both design methods. Aci318 code provides two design procedures for slab systems. The slab depths in the tables are m e a s u red from the top of the slab to the bottom of the ribs in the decking. Design of slab examples and tutorials by sharifah maszura syed mohsin. A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Posttensioned concrete design table 11 list of symbols used in the aci 31808 code m bal design moment resistance of a section with tendons and the necessary mild reinforcement to reach the balanced condition, nmm m u factored moment at section, lbin n c tension force in concrete due to unfactored dead load plus live load, lb p. The formwork shall be designed to withstand construction loads such as fresh concrete pressure and weight. The attached excerpted resource materials have been made. Materials used for this redesign is normal weight concrete with compressive strength of 4ksi and steel rebar with a yield stress of 60 ksi.
Reinforced concrete design 1 design of slab examples and. For slabonground floors it provides an understanding of the footingslab selection, design, detailing and construction requirements contained in as 2870 and. When a slabs length is more than twice its width l 2w then the slab can be considered a oneway slab. Additional reinforced internal ribs are used in the slab by additional reinforced internal ribs are used in the slab by introducing pontex, the structural cupolex accessory to provide a structure capable of spanning between stem walls or piles. Not trying to check your design, but cracks can mean. Twoway joist concrete slab floor waffle slab system analysis and design design the concrete floor slab system shown below for an intermediate floor with partition weight of 50 psf, and unfactored live load of 100 psf. It is a horizontal structural component, with top and bottom surfaces parallel or near so. Floor slab thickness was determined by aci 31802 table 9. The structural design of a concrete floor slab on grade is primarily controlled by the stresses caused by moving live loads and in some cases the stationary loads. It depends on purposes and location, but there several construction and design methods for nonsuspended slab.
Roof width must be greater than zero for all loads. Concrete slab design procedure7 design of continuous slab basics of reinforced concrete slab design slabs are generally designed on the assumption that they consists of. Reinforced concrete slab design using the empirical method. General overview of posttensioned concrete design instructor. The lateral loads are independently resisted by shear walls. The prestandard env for ec2 has now been available since 1992. Refer to aci 223 for special procedures recommended for the design and construction of shrinkagecompensating concrete slabs on. Ascc concrete contractors will work with all parties in addressing these issues. Twoway concrete floor slab with beams design and detailing design the slab system shown in figure 1 for an intermediate floor where the story height 12 ft, column crosssectional dimensions 18 in. A 2 2area 2 a c 2 2 posttensioned concrete design table 11 list of symbols used in the aci 31808 code cp area enclosed by the outside perimeter of the section, in a g gross area of concrete, in a 2 l total area of longitudinal reinforcement to resist torsion, in a o area enclosed by the shear flow path, sqin a oh area enclosed by the centerline of the outermost closed. Slabs may be supported on two sides only or have beams on all four sides.
Reinforced concrete slab systems on steel decks decking can serve as form, shoring and finished surface 18 gage 20 gage 22 gage slab thickness, simple continuous simple continuous simple c o n t i n u o u s. I have a situation where a recently poured suspended slab has some severe cracking in my opinion. Confusedsuspended concrete slabs, tensile and shear. The formwork is commonly built from wooden planks and boards, plastic, or steel. Indicate only tensile and shear reinforcement and label clearly. The design procedure includes determini ng slab thickness based. The depth of a concrete slab floor is very small compared to its span. A two way spanning concrete slab floor typically supported on concrete columns. Manual for design and detailing of reinforced concrete to. If you have any questions, contact your ascc concrete contractor or the ascc technical hotline at 800 3310668. Guide for concrete slabs that receive moisturesensitive. In this article, ill give a detailed explanation of each slab where to use particular slab. This document supplements information contained in the aci 360r and 302. Istructe ec2 concrete design manual 9 foreword the eurocode for the design of concrete structuresec2 is likely to be published as a euronorm en in the next few years.
This slab will have significant bending acting in both directions. Suspended concrete slab, suspended slab, cement slab. L center to center distance between the support b depth of slab. For a groundbearing slab, the formwork may consist only of side walls pushed into the ground. How does a suspended slab work, in a new home construction suspended reinforced concrete slabs are used in many applications in the construction industry. Even with the best floor designs and proper construction, it is unrealistic to expect. This type of concrete slab construction requires different concrete slab design from the one we normally see that is cast on the ground. The most common application of suspended slab in residential construction is used at garage floor where below the garage floor is a storage. What you see is a series of steel frames with cross braces holding them together. Design the roof slab, beam and column of house given in figure 1. Flexibility of future use with due consideration to long term deflections. Manual for design and detailing of reinforced concrete to the.
The structural design of a concrete floor slab on grade is primarily controlled by the stresses caused by moving live loads and in some cases the. Reinforced concrete design 1 design of slab examples. Precast suspended slabs design solutions included in this booklet, designers and engineers will find a design guide, load tables, and construction details for heldenfels enterprises inc. The main objective of this project is to analyze and design a multistory building 3ddimensional reinforce concrete frame, the design of reinforced concrete slabs, beams, columns, footings and. Theres no single method for design of nonsuspended slab. Find the following parameters for design moments in step 2 per unit width step 4 note. Effective span of slab shall be lesser of the two 1. Slabs can be onground, suspended, or a mix of both. Cantilevered concrete slab design structural engineering. The result is a lightly reinforced slab designed to offset the effects of temperature and shrinkage of the concrete. Some of them are outdated and many of them are frequently used everywhere. Steelreinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving see below. Rc slab design ec2 worked example bending reinforcement. Manual for the design of reinforced concrete building.
To facilitate its familiarisation the institution of structural engineers and. The cupolex floor slab can be fully suspended on reinforced concrete piles. Concrete slab, a very common and important structural element, are constructed to provide flat, useful surfaces. Concrete slab design procedure7 design of continuous slab basics of reinforced concrete slab design slabs are generally designed on the assumption that they consists of a number of beams of breadth one. The reinforced concrete design manual sp1711 is intended to provide guidance and assistance to professionals engaged in the design of castinplace reinforced concrete structures. With some limitations, reinforcement for slabs can be sized using the subgrade drag theory in order to increase the spacing of control or construction joints. Load chara c t e r istics must obv i ously va r y with the decking configurations and thickness, span re i n f o r cement, concrete stre n g t h and concrete thickness. Twoway concrete slab with beams spanning between supports. Concrete floor slab construction process includes erection of formwork, placement of reinforcement, pouring, compacting and finishing concrete and lastly removal of formwork and curing of concrete slab. A short tutorial showing how the main reinforcement in a simply supported slab is designed using ec2. Tm 580912 concrete floor slabs on grade subjected to.
The manual and advisory safety code of practice for concrete pumping67. Concrete slab floors come in many forms and can be used to provide great thermal comfort and lifestyle advantages. Design of slab for flexure 067 m unit width of slab. Manual for design and detailing of reinforced concrete to the september 20 code of practice for structural use of concrete 20 2. Foreword the reinforced concrete design manual sp1711 is intended to provide guidance and assistance to professionals engaged in the design of castinplace reinforced concrete structures. Vibration design of concrete floors for serviceability1 bijan o aalami2 this technical note covers the design of concrete floor systems for vibration, with an emphasis on simple and expeditious first estimates for a floors vibration response. Suspended concrete slab is referred to a cement slab that is not in contact with the ground. Nonsuspended slab is a slab that cast on the ground. Decisions required for the preliminary design of a floor system that are not discussed in this article, but are covered in other literature, include establishing slab and beam dimensions and concrete cover. When designing and building suspended slabs, this guide should be used in conjunction with aci 318 and 302. Refer to aci 223 for procedures for the design and construction of shrinkagecompensating concrete slabs onground.
Oneway and twoway slabs oneway slabs transfer the imposed. This guide covers the design and construction of composite slabs and beams, and addresses. I would like to know if somebody knows of a method suggestions, text or resources to design a cantilevered concrete slab that is going to be supported on masonry shearwalls. On the right is the slab formwork for a suspended concrete slab to a multi story building, but this system of concrete formwork could just as easily be used on an owner builder house. A two way spanning concrete slab roof typically supported on concrete columns. Concrete floor slabs on grade are subjected to a varie ty of loads and loading conditions. Reinforced concrete slab an overview sciencedirect topics.
The design of slabs on ground should conform to the recommendations of aci 360r. According to the 1995 aci code, all twoway reinforced concrete slab systems, including edge supported slabs. Jun 29, 2019 theres no single method for design of nonsuspended slab. Concrete slabs are often carried directly by columns without the use of beams or girders. The design of suspended floors should conform to requirements of aci 318 and aci 421.
It has been the most common material used in slabs but several new. Twoway joist concrete slab floor waffle slab system. The posttensioning institute pti design manual6 gives recommended spantothickness ratios for slabs and spantodepth ratios for beams. A one way slab will only have significant bending moments in the short direction.
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