Analysis and design of one way and two way slab in staad. After completion of this course, you are expected to be able to design the two types of rc. Footings example 1design of a square spread footing of a seven. Footings example 1design of a square spread footing of a sevenstory building. Department of mechanics, materials and structures english. Shear strength of twoway slabs shear failure occurs when inclined. The powerpoint files are posted rather than files in pdf format to permit the instructor to. This condition occur when the slabs are connected monolithically with support. Plan view of floor system assume partitions will not be damaged by deflections. Design of concrete structures 14th edition, 2009, by arthur h. Bending will take place in the two directions in a dishlike form. I have developed a microssoft excel software for design of a two way rcc slab.
This paper focuses on analysis of twoway ribbed and waffle slabs with hidden beams. Chapter 3 design of rectangular beams and oneway slabs. However, plastic method can be the best method for designing such cases of twoway slabs. 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. It is recommended to create the design of slab with the use of excel sheet as the process will be very simple and lots of time will be saved. Rectangular beams and one way slabs page 2 of 9 two methods. Determine moments at critical sections in each direction, normally the negative. Design of reinforced concrete components of a house. Analysis of two way ribbed and waffle slabs with hidden beams. The basic design procedure of a two way slab system has five steps. The main reinforcement or main support beam is only found in one way slabs. Following are the rcc slab design and detailing guidelines. 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. This example is to be used for educational purposes only.
This method requires various formulas for different conditions of rc slab. This example goes through the design of a simplysupported oneway slab on beams. Flat plate concrete floor system does not use beams between columns or. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. There are many methods that are used to analyze twoway slabs and the precision of these methods vary depending. The results of the parametric analysis indicate that the deflection of posttensioned twoway slab is more affected by the span length than by the other variables. The twoway slab shown in figure below has been assumed to have a thickness of 7. The following example illustrates the example building. For example take a handerchief similarly hold it with two hands and apply load. In this example deflection will be calculated and checked to satisfy project. Here discribed for two way simply supported slab with better solution and also told about of how to use is code in two way slab design. There are many methods that are used to analyze two way slabs and the precision of these methods vary depending. A reinforced concrete slab is built integrally with its supports and consists of equal span of 15 ft. This situation happen when slab were supported at all four span sides and.
Design of a two way rcc slab structural engineering forum. Design of slab examples and tutorials by sharifah maszura syed mohsin example 2. Cad drawing plan view of a reinforced concrete floor slab example. 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. Mathematical structural analysis of one way ribbed slabs was introduced. Despina emmanuel, studied marketing and business strategy at university of. Direct design method design of two way floor system for slab. 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. Shear strength of two way slabs shear failure occurs when inclined cracks form due to flexural and shearing stresses. Reinforced concrete design abi aghayere, professor, department of.
In the previous example, it was found that the equivalent load equals 0. Answer to a one way solid concrete slab is to be used for a simple span of 15 ft. Fanella, which appeared in the october 2001 edition of structural engineer magazine. Reinforced concrete design 1 design of slab examples and. A discreteelement method of multipleloading analysis for. No redistribution is allowed when method 1 or method 2 of analysis in section 3. In the strength design method, the service loads are increased sufficiently by factors in order to obtain the load at which teaching twoway ribbed slab analysis and design using the mathcad program mohammed s. The effect of fixing the corners of the slab against lifting 5. A discreteelement method of multipleloading analysis for twoway bridge floor slabs by john j. Application of the yield line theory for more complex situations 8. Bending will take place in the two directions in a dishlike fo.
For designing two way slab refer is code 4562000 and sp16. Analysis and design of slabs two way two way edge supported slabs two way slabs. Assume partitions cannot be damaged by deflections. The design bending moment of twoway restrained slab can be calculated as follows. Two way slab design spreadsheets to eurocode 2 two way spanning slabs for rectangular slabs with standard edge conditions and subject to uniformly distributed loads, normally the bending moments are obtained using tabulated coefficients. Two way joist waffle slab design approach and methodology 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. Jul 10, 2017 this example goes through the design of a simplysupported oneway slab on beams. In this article, it is assumed that slab thickness is determine but calculation of column and middle strips is explained. 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. Slab resting on walls or sufficiently deep and rigid beams on all sides. Example design of two way edgesupported solid slab. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects.
Teaching twoway ribbed slab analysis and design using the. The basic design procedure of a twoway slab system has five steps. 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. The program covers wide range of two way slab systems and can be used for more complex slab layouts.
The floor is to be designed to carry a service live load and a dead load on the slab due to selfweight plus weight of. Generally, there are two types of slab which are one way and two way slabs. Design of reinforced concrete structures ii two way slabs 1 1. Unless otherwise noted, all referenced table, figure, and equation. Sep 11, 2017 design of two way slab design education. Use the aci 318 direct design method to design an interior bay of a flat plate slab system of multi bay building. Rectangular beams and oneway slabs page 2 of 9 two methods. This course design of reinforced concrete slab gives you detailed understanding, explanations and procedures for the design of rc slabs. The following example illustrates the design methods presented in the pca book simplified design reinforced concrete buildings of moderate size and height third edition. Oneway slabs transfer the imposed loads in one direction only. Distribute moments transverse at critical sections to column and middlestrip and if.
To comply with aci 318, should a designer check punching shear stress with the simultaneous biaxial moments reported by such a model. Twoway slabs have two way bending unlike oneway slab. Design of reinforced concrete structures ii twoway slabs 1 1. Redistribution of 10% may be allowed when method 3 or method 4 is adopted. Slab design reading assignment chapter 9 of text and, chapter of aci31802. Basic steps in two way slab design choose layout and type of slab. Continuous one way slab near middle of end span m 0.
Summary and comparison of twoway slab design results. They may be supported on two opposite sides only fig. Chapter 3 design of rectangular beams and oneway slabs 12. Bridge approach slab analysis and design incorporating elastic soil support presented by. The same is true for a two way slab or any other floor system.
Two way slab design spreadsheets to eurocode 2 engineering. 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. Slabs and flat slabs lecture 5 19 th october 2016 contents lecture 5 designing for shear in slabs including punching shear detailing solid slabs flat slab design includes flexure worked example exercise punching shear. Twoway slab systems offer several possible arrangements for the tendon layout 10. For good college marketing corporate development investor relations. F is the total design ultimate load on the strip of slab between adjacent columns considered 1.
Analysis and design of slabs two way two way edge supported slabs twoway slabs. Master of science and hereby certify that, in their opinion, it is worthy of acceptance. Two bays one way ribbed slab is analyzed by both traditional and finite element. Design the concrete slab and calculate the required tensile reinforcement for the main and the secondary direction.
These are the direct design method presented in chap. Design of reinforced concrete, 9th edition wec civilians. All available load test results indicated that the flat plate or flat slab was a most efficient design with an adequate safety factor. Twoway flat plate concrete floor system design structurepoint. Accordingly, main reinforcement is required in the two directions. Twoway 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. The dimensions of an interior bay are shown in figure 1. The unit weights of concrete and soil are 150 pcf and 120 pcf. Reinforced concrete, 2014, 9th edition, aci 31811 code edition, by jack c. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only. Therefore, primary reinforcement is presented in both directions for resisting the loads. Design of reinforced concrete structures ii twoway slabs. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan.
Twoway spanning slabs for rectangular slabs with standard edge conditions and subject to uniformly distributed loads, normally the bending moments are obtained using tabulated coefficients. The output of the program for the slab in the example is shown in the following pages. Jul 22, 2015 design of two way ribbed slab 18 x 25 m clear span 1. One way and two way slabs one way slabs transfer the imposed loads in one direction only. 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. Reinforced concrete slab design guidelines a effective span of slab. 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. Aci 31811 code provides two methods for two way slab design one of which is direct design method. 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. Such coefficients are provided later in this section.
A discreteelement method of multipleloading analysis for two way bridge floor slabs by john j. With the advent and popularity of finite element analysis software, engineers can create sophisticated models of two way slabs supported by columns. Oneway and twoway slabs oneway slabs transfer the imposed. Oneway and twoway slabs university of asia pacific.
Allowable stress design or working stress design wsd 2. Two way slabs have two way bending unlike one way slab. Design the concrete slab and calculate the required tensile reinforcement for the. No certain method can be found in the design codes or references for designing twoway slabs subjected to concentrated loads. Shear strength of beamless slabs usually a controlling factor. Advanced slab design mode enables concrete slabs defined with or without holes to be designed using the ramconcept or adaptbuilder software.
Time saving design aids twoway slabs page 1 of 14 the following example illustrates the design methods presented in the article timesaving design aids for reinforced concrete, part 2. Design of two way ribbed slab 18 x 25 m clear span 1. Design the slab following the provisions of the aci code. Two way slab design by direct design method as per aci 31811. The pca computer program pcaslab can be used to expedite the design of different slab systems. Waffle slab analysis and design is similar to the procedure used with flat plates except that special considerations need. 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. Analysis and design of slabs two way civil engineers pk.
A oneway reinforced concrete slab analyzed with rcsolver according to eurocode 2 specifications. Main reinforcement for two way slabs designs in both directions. Design of a two way rcc slab structural engineering. Design examples look at example 7 design of a flat plate floor without spandrel beams direct design method look at example 9 design of a twoway slab with beams in both directions. In two way slab, load is delivered in both the directions.
What are the basic differences between oneway and twoway slabs. Beams of width and depth are provided on all column lines. Reinforced concrete slab design and detailing guide is456. 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. Twoway concrete slab with beams spanning between supports.
One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. An optimal plan geometry with all same supports is a square, based on load distribution into both directions. Panak hudson matlock research report number 56 development of methods for computer simulation of beamcolumns and gridbeam and slab systems research project 356356 conducted for the texas highway department. Design examples look at example 7 design of a flat plate floor without spandrel beams direct design method look at example 9 design of a two way slab with beams in both directions. Effective span of slab shall be lesser of the two 1. There are some basic steps which we generally do while designing theoretically some steps are rcc slab design guidelines. This paper focuses on analysis of two way ribbed and waffle slabs with hidden beams. Twoway joist waffle slab design approach and methodology. Preliminary design of slab thickness thickness design depends on boundary conditions supports.
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