This condition occur if the slab supported by two side of beam or walls. Slab is a common term used to describe the structural elements such as floors and roofs where the thickness of the element is very small compared to the length and. End column one side of the column parallel to the axis of the moment is less than four times the slab thickness from a slab edge in cases 2, 3 and 4, column is assumed to be at the edge of the slab. Oneway spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Reinforced concrete slab design and detailing guide is456. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. In case of slabs thin members, no need of even minimum shear reinforcement. With strength design method, the working dead load dl and live load ll are multiplied by. Rc slab design ec2 worked example shear and deflection checks duration. Advanced slab design mode enables concrete slabs defined with or without holes to be designed using the ramconcept or adaptbuilder software. Strength design or ultimatestrength design usd strength design or ultimatestrength design usd with strength design method, the working dead load dl and live load ll are. Two way 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. Design of reinforced concrete structures ii twoway slabs 1 1.
Pdf design calculation design of one way slab slab s1. An optimal plan geometry with all same supports is a square, based on load distribution into both directions. A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. A oneway reinforced concrete slab analyzed with rcsolver according to eurocode 2 specifications. Analysis and design of slabs one way civil engineers pk. As they are oneway slabs i treat them as wide beams.
Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. One way and two way slab design aspect the slab provides a horizontal surface and is usually supported by columns,beams or walls. Rectangular beams and one way slabs page 3 of 9 design of rectangular beams and one way slabs continued a. Shear in oneway slabs under concentrated load close to support. Bridge approach slab analysis and design incorporating elastic soil support presented by.
Figure 1 twoway slab with beams spanning between all supports. Flat plate concrete floor system does not use beams between columns or. Following are the rcc slab design and detailing guidelines. Master of science and hereby certify that, in their opinion, it is worthy of acceptance. Design the slab following the provisions of the aci code. Design of reinforced concrete structures ii twoway slabs. What is the design of a one way slab and a two way slab. If the slab is supported in the short direction only, the slab may crack in the long direction until the reinforcement in the short direction pick up the strength. Ce 433, fall 2006 slab design example 1 6 design a oneway slab for an exterior bay of a multistory office building using the information specified below. Design of reinforced concrete structures ii two way slabs 1 1.
Composite deckslab systems are a very efficient way to. Reinforced concrete slabs compatibility limit design. This paper focuses on analysis of two way ribbed and waffle slabs with hidden beams. Beams of width and depth are provided on all column lines. Rectangular beams and one way slabs page 2 of 9 two methods. Slab slabs are an important structural component where prestressing is applied.
Pdf cost optimum design of reinforced concrete simply. Difference between one way slab and two way slab system. Introcduction slab in which the deflected surface is predominantly cylindrical termed as oneway slabs spanning in the direction of curvature. Twoway concrete floor slab with beams design and detailing. Although the major reinforcement in one way slab span is in the short direction, yet at the corner, the moment is actual supported by beams at both directions. Minimum thickness of nonprestressed oneway slab normal. View test prep concrete 3 design of concrete beam and slab twoway slab part 22 from engineerin 101 at royal melbourne institute of technology. Pdf shear in oneway slabs under concentrated load close to. Each single slabs are referred to as panels, if the slab is continuous over supports. The basic design procedure of a two way slab system has five steps. Design of reinforced concrete structure one way slab presented by md. In addition to general ultimate and serviceability limit state design issues, practical design considerations such as the formation of holes in the slab, support details, fire protection, and attachments to the slab are discussed. Chapter 3 design of rectangular beams and oneway slabs. Two way slabs are normally supported from four sides.
In this work the cost optimization design of rc oneway slabs was performed by the. The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Allowable stress design or working stress design wsd 2. They have been given appropriate profiles for placing of the tendons, which is based on the design of the flat slab. Ribbed slabs oneway joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. Design criteria for deflection capacity of conventionally. Distribute moments transverse at critical sections to column and middlestrip and if. Two way slab design by direct design method as per aci 31811, step by step procedure and limitations of direct design method for two way slab is presented. Oneway and twoway slabs oneway slabs transfer the imposed. Example design of two way edgesupported solid slab. Ribbed slabs one way joists introducing voids to the soffit of a slab reduces dead weight and increases the efficiency of the concrete section. Introcduction slab in which the deflected surface is predominantly cylindrical termed as one way slabs spanning in the direction of curvature. Effective span of slab shall be lesser of the two 1.
Plan view of floor system assume partitions will not be damaged by deflections. Various simplified methods are therefore adopted for determining moments, shears and reactions in such slabs. Chapter 3 design of rectangular beams and oneway slabs 12. I am doing oneway slabs and hope you can clean up my doubts about the one way shear in slab. Total load is nothing but, w i can say, in this case which is. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in plane loads, if any, per unit width of slab. Dec, 2017 beam and slab arrangement can be the best example for one way and two way slabs. A reinforced concrete slab is built integrally with its supports and consists of equal span of 15 ft. If slab supported by four side of beams or walls, the slab is considered oneway if ratio of long span ly to short span lx greater than 2.
Reinforced concrete slab design and detailing guidelines for depth of slab, loads on slab, reinforcement guide for oneway and twoway slabs as per is 456. If none of the values satisfies, you need to change d. Nov 15, 2014 one way slab here i solve a probleam based on the one way slab, the diamentions are provided in the probleam 1st determine the aspect ration and with respect to the aspect ratio the type of slab. Analysis of two way ribbed and waffle slabs with hidden beams. The overhang of the slab beyond the face of the column is not included in the calculations. In two way slabs, load will be carried in both the directions.
They may be supported on two opposite sides only fig. If slab is supported on all four sides and r shorter side longer side pdf. Reinforced concrete slab design and detailing guidelines for depth of slab, loads on slab, reinforcement guide for one way and two way slabs as per is 456. Whatever may be the width of the slabs it should always be designed for a width of equal to one metre and the same design should be adopted for the rest of the slab. Slab is checked for deflection shear and development length. The building is located in seismic zone iii on a site with medium soil. D mm d 105 mm loads on slab self weight of slab 3. For a twoway slab supported on beams these strips carry the load to the beams. The design of composite slabs and beams is discussed in detail in relation to the eurocodes and bs 5950. Shear due to loads always must be less than the shear strength of concrete. Concrete 3 design of concrete beam and slab twoway slab. Difference between one way slab and two way slab simple. Slab are considered as oneway if the main reinforcement is designed only in one direction. Oneway and twoway slabs university of asia pacific.
Continuous beam if it is the other way, for end span with 1 end fixed and the other. One way slab one way slabs are such slabs in which the loads are shared only by the shorter direction of the slab. For purposes of analysis and design, a unit strip of such a slab cut out at right. The saving of materials tends to be offset by some. Quite popular and widely used among these methods is one using moment coefficient based on the 1963 aci code, for the special case of twoway slabs supported on four sides by relatively stiff beams. Twoway flat plate concrete floor system design structurepoint.
Parameters include support conditions nine cases, span ratios lalb 0. Twoway concrete slab with beams spanning between supports. Slabs having supports on less than four sides can be designed as one way. At about the same time in 1956, powell 15 tested nine small. There are many methods that are used to analyze two way slabs and the precision of these methods vary depending. For 1m slab width, moment, shear force, oneway continuous slab for continuous slab, moment and shear force can be obtained from table 3. Before we start the design of slabs, let us see what our words says related to your effective span. If slab is supported on all four sides and r shorter side longer side one way slab. One way and two way slab design aspect online civilforum. May 02, 2017 two way slab is a slab supported by beams on all the four sides and the loads are carried by the supports along both directions, it is known as two way slab. Reinforced concrete, 2014, 9th edition, aci 31811 code edition, by jack c. In two way slab, the ratio of longer span l to shorter span b is less than 2.
Two way slab design by direct design method as per aci 31811. Design the concrete slab and calculate the required tensile. A slightly deeper section is required but these stiffer floors facilitate longer spans and provision of holes. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in. In case of one ways slabs, the aci approximate analysis is applicable to one way slab system where a one way slab is continuous with a one way slab. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Design of concrete structures 14th edition, 2009, by arthur h. Lb2 is one way slab lb content and search advanced slab. Twoway concrete slab on beams floor analysis and design. One way and two way slabs one way slabs transfer the imposed loads in one direction only. Ce 433, summer 20 slab design example 1 5 design a one. There are some basic steps which we generally do while designing theoretically some steps are rcc slab design guidelines. Preliminary design of slab thickness thickness design depends on boundary conditions supports. Two way slab is a slab supported by beams on all the four sides and the loads are carried by the supports along both directions, it is known as two way slab.
Normally it works fine but this time after carrying out the calculations the slabs fail in shear because of there are some huge point loads near the support. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. Design methods validated by experimental evidence for flat slabs supported on. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. Pdf the paper presents the cost optimization of reinforced concrete simply supported. Pdf irregular flat slabs designed according to the structural. Reinforced concrete design 1 design of slab examples and. Design of oneway slab free download as powerpoint presentation. Bending will take place in the two directions in a dishlike fo. These are the direct design method presented in chap. Analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. Design procedure steps for one way slab slab design steps.
One way slab is the most basic and common type of slab. Generally, there are two types of slab which are one way and two way slabs. The service live load is 100 psf and 4000 psi concrete is specified for use with steel with a yield stress equal to 60000 psi. Rectangular beams and oneway slabs page 2 of 9 two methods. Here ratio of longer span of slab to the shorter span of slab is greater than 2. One way slab is supported by two parallel beams or walls. The slab has to carry a distributed permanent action of 1. One way slab design procedure with example design of one. The basic design procedure of a twoway slab system has five steps. One way shear in slab structural engineering general. Two way flat plate concrete floor system analysis and design the concrete floor slab system shown below is for an intermediate floor to be designed considering partition weight 20 psf, and unfactored live load 40 psf. A slab or panel is said to be two way slab if the ratio of longer span to the shorter span is not greater than 2 two.
Jul 18, 2016 there are some basic steps which we generally do while designing theoretically some steps are rcc slab design guidelines. The ratio lb which is less than 2 is known as two way slab. The strength design method was included for the first time in the 1956 edition of the. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Analysis and design of one way and two way slab in staad. If the slab is supported in the short direction only, the slab may crack in the long direction until the reinforcement in the short direction pick up. Steelreinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only. The design procedure for a uniformly loaded one way reinforced slab can be divided in the following steps. A one way reinforced concrete slab analyzed with rcsolver according to eurocode 2 specifications. Assume partitions cannot be damaged by deflections. A six storey building for a commercial complex has plan dimensions as shown in figure 1.
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