Before the start of two way slab design, slab depth should be determined in addition to specify column strips and middle strips. In this article, it is assumed that slab thickness is determine but calculation of column and middle strips is. Recommendations for finite element analysis for the design of. Fanella, which appeared in the october 2001 edition of structural engineer magazine. I have developed a microssoft excel software for design of a two way rcc slab. Design of slab examples and tutorials by sharifah maszura syed mohsin. The specified design strength of the concrete, is 25 mpa and the specified yield strength of the reinforcement, fy, is 400 mpa. Part three is an exampleintensive course, with key concepts introduced. A slab is a concrete structure constructed to provide a flat surface. How to design two way slab with coefficient method in excel sheet slab refers to a common structural component of modern building. Distribute moments transverse at critical sections to column and middlestrip and if.
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. The proposed slab system must be able to be constructed at a. Joint efforts by researchers, design engineers and for example, a posttensioned 10 in cost between reinforced and posttensioned concrete flat slabs.
As with any design function, the designer must ultimately understand and approve the loads for a given project as well as the overall design. Reinforced concrete design 1 design of slab examples and. In flatplate floors, slab column connections are subjected to high shear stresses produced by the transfer of axial loads and bending moments between slab and columns. The document is intended primarily for design engineers, but we shall be very pleased if it is also of use. Design of slab two way excel sheet design spreadsheets the specified design strength of the concrete, is 25 mpa and the specified yield strength of the reinforcement, fy, is 400 mpa. 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. The unisdr secretariat is supporting the development and distribution of tools like this handbook, as a part of its mandate for coordinating the. Analysis and design of slabs two way two way edge supported slabs two way slabs. For concrete slab design, the slab dimensions and the size and spaci ng of reinforcement shall. General design process though many details must be included in the design of a slab on grade, three important components are slab thickness, reinforcement.
The building is located in seismic zone iii on a site with medium soil. Analysis of two way ribbed and waffle slabs with hidden beams. Hillerborgs strip method of design 1, 2 is a powerful and versatile technique for designing two way reinforced concrete slabs and plates. This course provides the documentation to enable the use of a posttension design spreadsheet program for one way concrete beam and slab and two way concrete slab systems. Jul 22, 2015 design of two way ribbed slab 18 x 25 m clear span 1. Powered by the equivalent frame method of analysis and design per latest american aci 31814 and canadian csa a23. Multi storey, post tension, two way, design, comparison. Design of a two way rcc slab structural engineering forum. Design of a two way slabs for punching shear resistance. 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. Design of reinforced concrete structures ii twoway slabs. Master of science and hereby certify that, in their opinion, it is worthy of acceptance. Posttensioned concrete design spreadsheet program a pdh. The following example illustrates the example building.
The purpose of this paper is to demonstrate the performance of link slabs designed with ductile ecc material for macroscopically crack free concrete bridge decks. No certain method can be found in the design codes or references for designing two way slabs subjected to concentrated loads. The document two way slabs civil engineering ce notes edurev is a. In this video deisgn of two way slabs has been covered using is 456. In two way slabs, load will be carried in both the directions. 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. The first is the familiar beamtype shear leading to diagonal tension failure. Manual for design and detailing of reinforced concrete to the code.
Slabs are usually used in floor and roof construction. Oneway and twoway slabs university of asia pacific. Reinforced concrete slab design and detailing guide is456. We examined webbuilding spider\nassemblages with and without deer, using a paired exclosurecontrol design in\ ntwo regions of the northern hardwoods forest of the u. Design of reinforced concrete structures ii two way slabs 1 1. Teaching twoway ribbed slab analysis and design using the. Rectangular beams and one way slabs page 2 of 9 two methods. Ce 433, summer 20 slab design example 1 5 design a one.
Fundamentals of posttensioned concrete design for buildings. Reinforced concrete design 1 design of slab examples. The first aa solution is a twoway concrete solid slab with depth3 h 18 cm supported by 0,25. If the ratio of longer dimension of the slab panel to the shorter dimension is greater than or equal to 2 then it is designed as one way slab. In two way slabs shorter direction strip carry greater %age of load. Manual for design of slabs, pile caps and footings. Here the slab or slab panel is supported along its four edges by relatively deep, stiff, monolithic concrete beams or walls or steel girders.
Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. Static equilibrium of two way slabs total moment in both beams full load was transferred eastwest by the planks and then was transferred northsouth by the beams. The coefficient method may be the simplest, easiest and the quickest approach for the design of two way slab supported by edge beam on all slab sides. Two way slab design by direct design method as per aci 31811. 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. Allowable stress design or working stress design wsd 2. 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.
In the strength design method, the service loads are increased sufficiently by factors in order to obtain the load at which teaching two way ribbed slab analysis and design using the mathcad program mohammed s. Posttensioned oneway slab pennsylvania state university. Applicable particularly to long narrow slabs or footings, this analysis considers the slab to act as a wide beam. Concrete 3 design of concrete beam and slab twoway slab. This method requires various formulas for different conditions of rc slab. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas.
A simplified method for designing rc slabs under concentrated. The following example illustrates the design methods presented in the pca book simplified design reinforced concrete buildings of moderate size and height third edition. Chapter 3 design of rectangular beams and oneway slabs. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. One way and twoway slabs one way slabs transfer the imposed loads in one direction only. Beamless slabs beamless slabs are supported only on columns and are applied mostly in large industrial and public. Slab slabs are an important structural component where prestressing is applied. A six storey building for a commercial complex has plan dimensions as shown in figure 1. The report addresses the planning, design, and detailing of slabs.
Generally, there are two types of slab which are one way and two way slabs. How to design a twoway slab free download as powerpoint presentation. The same is true for a two way slab or any other floor system. Preliminary design of slab thickness thickness design depends on boundary conditions supports. Two way edgesupported slabs two way edgesupported slabs. Performance of bridge deck link slabs designed with ductile ecc. View test prep concrete 3 design of concrete beam and slab twoway slab part 22 from engineerin 101 at royal melbourne institute of technology. Use i wsd, ii usd to design the twoway slab shown below, carrying floor finish 30 psf, random wall 50 psf and live load 60 psf given. In the selection of ecc material, the property requirements on the link slab material as well as processing demands were considered. However, plastic method can be the best method for designing such cases of two way slabs.
It is generally horizontal and contains lesser thickness with regards to its span. One way and two way slabs one way slabs transfer the imposed loads in one direction only. Design of slabs onground reported by aci committee 360 aci 360r06 this document presents information on the design of slabs onground, primarily industrial floors. Two way concrete slabs with openings the static system and the design of reinforcement. The slab is to be designed as a reinforced concrete two way slab supported on beams. Waffle slab analysis and design is similar to the procedure used with flat plates except that special considerations need to be taken into account to reduce the complexity of calculations needed when. Two way slabs have two way bending unlike one way slab. Contains all design checks required by the american concrete institute code and all the conditions that must be met during the design process. Please read the lauses mentioned in the video while solving the problem. In two way slab, the ratio of longer span l to shorter span b is less than 2. Example design of two way edgesupported solid slab.
Chapter 3 design of rectangular beams and oneway slabs 12. This handbook on good building design and construction in the philippines does exactly that, capturing the potential of increased resilience through good construction. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. Reinforced concrete, 2014, 9th edition, aci 31811 code edition, by jack c. The unit weight of reinforced concrete is assumed to be 24 knm3. Two way columnsupported slabs two way columnsupported slabs. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. Flat plate concrete floor system does not use beams between columns or. 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. All available load test results indicated that the flat plate or flat slab was a most efficient design with an adequate safety factor. The slab has to carry a distributed permanent action of 1. Two kinds of shear may be critical in the design of flat slabs, flat plates, or footings.
An optimal plan geometry with all same supports is a square, based on load distribution into both directions. It deals with the problem of openings in twoway concrete slabs. Following are the rcc slab design and detailing guidelines. For 1m slab width, moment, shear force, oneway continuous slab for continuous slab, moment and shear force can be obtained from table 3. Two way joist slab often called two way ribbed slab or waffle slab is an economical floor system when the spans are long andor loads are high. Reinforced concrete design in accordance with as3600 ccaa. Slabs can be designed by direct design method known as ddm and another method for design is coefficient method which is the easier one. Time saving design aids two way slabs page 1 of 14 the following example illustrates the design methods presented in the article timesaving design aids for reinforced concrete, part 2. Concrete slabs are commonly divided into the following types. 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. Dissatisfaction with results of previously required procedures of analysis and design for two way slab beam systems was the original reason for the massive research upon two way slab systems begun about 1955. To make the slab design independent of the type of rail, we will place the wheel load 1 from the nominal face of the rail 1ft from the edge of the slab. Jul 10, 2017 this example goes through the design of a simplysupported one way slab on beams.
Redistribution of 10% may be allowed when method 3 or method 4 is adopted. Jan 15, 2017 one way slabs are those supported continuously on the two opposite sides so that the load sare carried along one direction only. No redistribution is allowed when method 1 or method 2 of analysis in section 3. Unless otherwise noted, all referenced table, figure, and equation numbers are from that book. Beams of width and depth are provided on all column lines. The direction in which the load is carried in one way slab is called the span.
Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types. There are several methods by which two way slabs can be designed. Bending will take place in the two directions in a dishlike fo. The first reinforced concrete design manual formerly titled aci design handbook was developed in accordance with the design provisions of 1963 aci 318 building code by aci committee 340, design. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Basic steps in two way slab design choose layout and type of slab.
Analysis and design of slabs two way civil engineers pk. Fundamentals of posttensioned concrete design for buildings part one. One way and two way slab reinforcement in detail at sit duration. Bridge approach slab analysis and design incorporating elastic soil support presented by. Program scope, design assumptions, design methodology, program limitations, description of inputoutput, hardware requirements. Design of slabtwo way excel sheet online civilforum. The basic design procedure of a two way slab system has five steps. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. Flat slab system is an important division of concrete floor system. The method is based on the lower bound theorem of plasticity, meaning that a design based on the strip method is always safe. Oneway and twoway slabs oneway slabs transfer the imposed. Analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. From the study it is considered that post tension slab is more economical than two way slab. All methods are viable provided that the safety and serviceability of the elements are within the acceptable limits.
Reinforced concrete slab design using the empirical method. Twoway joist waffle slab design approach and methodology. 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. Design of concrete structures 14th edition, 2009, by arthur h. This paper focuses on analysis of two way ribbed and waffle slabs with hidden beams. Examples of this are the detailed design of precast concrete elements and posttensioned slabs. A civil engineer must know all the aspects regarding the flat floor system. Bending will take place in the two directions in a dishlike form. Flat slab analysis, design and detailing pdf civil. Assume partitions cannot be damaged by deflections. The slab panel is part of the suspended floor slab and so the upper and lower surfaces of the slab are interior for durability cover and crack control purposes.
Slab resting on walls or sufficiently deep and rigid beams on all sides. Background information on design theories is followed. Chapter 3 design loads for residential buildings methods for determining design loads are complete yet tailored to typical residential conditions. Handbook on good building, design and construction in the. There are many methods that are used to analyze two way slabs and the precision of these methods vary depending. They may be supported on two opposite sides only fig. The value of 23 is appropriate for two way spanning slab if it is continuous over one long side 3.
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