Chapter 3 design of rectangular beams and oneway slabs 12. Design of two way slab example pdf flat slab design pdf bs 8110 concrete design for slab how to calculate formwork for slab how to pour a concrete slab post tension slab slab on grade foundation concrete beam and slab bridge how to pour a 26x36 concrwte concrete slab operation management 9th edition myomlb nigel slab usercentered design, activitycentered design, and goaldirected design modeling the collaborative design of the automotive powertrain system based on the design structure. Rectangular beams and one way slabs page 2 of 9 two methods. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. The dimensions of an interior bay are shown in figure 1. The basic design procedure of a two way slab system has five steps. Two way slabs are normally supported from four sides. For a sample output refer to twoway flat plate concrete floor slab design example. Two way slab design spreadsheets to eurocode 2 en 19921. Rectangular beams and oneway slabs page 2 of 9 two methods. The same is true for a two way slab or any other floor system where. Slab shear strength twoway shear check the adequacy of slab thickness for punching shear twoway shear at an interior column figure 4. Aci318 code provides two design procedures for slab systems.
Distribute moments transverse at critical sections to column and middlestrip and if. Analysis and design of slabs two way civil engineers pk. The output of the program for the slab in the example is shown in the following pages. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. For flat plates and slabs the column connections can vary between. Pdf the article is about design of prestressed slabs. Design of reinforced concrete structures ii two way slabs 1 1. Two way slab design static equilibrium of twoway slabs total moment in both beams full load was transferred eastwest by the planks and then was transferred northsouth by the beams. Top view of continuous rc circular twoway ribbed slab. Useful illustration example is presented in this study according to the available materials in iraq to facilitate the job of designers. The same is true for a two way slab or any other floor system. The specified design strength of the concrete, is 25 mpa and the specified yield strength of the reinforcement, fy, is 400 mpa. If the ratio of long span to short span is less than or equal to 2, the slab is to be defined as two way slab or slab spanning in one direction.
Pdf slabs are the flooring systems of most structures including office. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. Shear strength of beamless slabs usually a controlling factor. 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.
Design of reinforced concrete structures ii twoway slabs 1 1. The following example illustrates the example building. In this example deflection will be calculated and checked to satisfy project. Direct design method, that could have been named the direct analysis method because it determines or prescribes moments for different parts of the slab panel without the need to conduct structural analysis, is explained in the following sections. Dissatisfaction with results of previously required procedures of analysis and design for twoway slabbeam systems was the original reason for the massive research upon twoway slab systems begun about 1955. Two way slabs have two way bending unlike one way slab. Assume partitions cannot be damaged by deflections. Aci 31811 code provides two methods for two way slab design one of which is direct design method. 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. All available load test results indicated that the flat plate or flat slab was a most efficient design with an adequate safety factor. The ratio of the total costs was found to be within the range 1. It shows possible solutions of twoway prestressed floors depending on different factors. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown.
Effective depth d span ldbasic x modification factor for obtaining modification factor, the percentage of steel for slab can be assumed from 0. Sandwich slabs may have the disadvantage of a larger weight compared to the ribbed ones but on the other hand, they have the advantage that their spans and supports behave in the same proper way. In twoway slabs shorter direction strip carry greater %age of load. Cornell university, david darwin university of kansas, charles dolan university of wyoming 3. Design the slab system shown in figure 1 for an intermediate floor where the story height 12 ft, column cross sectional dimensions 18 in.
Design of concrete structures 14th edition, 2009, by arthur h. In two way slabs shorter direction strip carry greater %age of load. These slabs are constructed to provide flat surfaces, usually horizontal, in building floors, roofs or other types of structures. Design of a two way rcc slab structural engineering forum. I have developed a microssoft excel software for design of a two way rcc slab. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types.
The high accuracy in design calculations of structures is undesirable because there is no. Use the aci 318 direct design method to design an interior bay of a flat plate slab system of multi bay building. 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. 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. Comparison of one way and two way slab behavior one way slabs carry load in one direction. Difference between one way slab and two way slab system the one way and two way slab systems are the most commonly used floor system in the reinforced concrete structure. For designing two way slab refer is code 4562000 and sp16. Chapter 3 design of rectangular beams and oneway slabs. Step 2 slab member moment capacity check using structural toolkit now we have our maximum positive and negative design moments, we can use the structural toolkit concrete member to check the flexural capacity. 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 aids for building codes, whose mission was to develop handbook editions in accordance with the aci 318 building code. Full load was transferred eastwest by the planks and then was.
Generally, there are two types of slab which are one way and two way slabs. Reference 5 focused on analysis of two way ribbed slabs with. Design calculation for two way slab as per bs 8110. Jun 30, 2014 design of reinforced concrete two way slabs. Flat slab analysis and design free version download for pc. Such coefficients are provided later in this section.
Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Can be used for larger spans with relatively higher cost and higher deflections oneway joist system suitable span 6 to 9m with ll 46knm2. Pdf design of reinforced concrete circular slabs by twoway. Deep ribs, the concrete and steel quantities are relative low expensive formwork expected. Flat slab analysis and design designs beamless concrete slab floors flat slab or waffle slab in accordance with aci 318. Two way slab design spreadsheets to eurocode 2 engineering. Load transfer in a oneway slab, b twoway slab nilson fig. Beams of width and depth are provided on all column lines. Slabs are generally designed on the assumption that they consists of a number of beams of breadth one meter. For uniformly distributed loads of w per square foot of the slab, each strip acts approximately like a simple beam uniformly loaded by its share of w.
This situation happen when slab were supported at all four span sides and. Two way slab design to aci free download and software. Twoway concrete floor slab with beams design and detailing. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Comparison of oneway and twoway slab behavior economic choices oneway slab on beams suitable span 3 to 6m with ll 35knm2. Basic steps in two way slab design choose layout and type of slab. Jul 10, 2017 this example goes through the design of a simplysupported one way slab on beams. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. Allowable stress design or working stress design wsd 2. The design bending moment of twoway restrained slab can be calculated as follows. In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. The direction in which the load is carried in one way slab is called the span.
Twoway slabs have two way bending unlike oneway slab. Difference between one way slab and two way slab simple. This spreadsheet is an extremely efficient tool and allows to quickly design two way slabs to aci code. The ratio lb which is less than 2 is known as two way slab. Nov 30, 2018 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. Two way slab design based on aci 31811 using finite element method. Reinforced concrete design 1 design of slab examples and. Oneway and twoway slabs university of asia pacific. Civil engineering ebooks and many more civil engineering downloads.
A single slab with oneway reinforcement rebars will be analyzed with rcsolver. 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. Load transfer in a one way slab, b two way slab nilson fig. Create a new concrete member within structural toolkit and enter the depth 170mm, concrete strength 32mpa and web width of s type representing a slab. The program covers wide range of twoway slab systems and can be used for more complex slab layouts. Interior bay dimensions 20 24 this example is to be used for educational purposes only. The unit weight of reinforced concrete is assumed to be 24 knm3. 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.
This condition occur when the slabs are connected monolithically with support. The program covers wide range of two way slab systems and can be used for more complex slab layouts. This example goes through the design of a simplysupported oneway slab on beams. Reference 5 focused on analysis of twoway ribbed slabs with. Main reinforcement for two way slabs designs in both directions. 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. Example design of two way edgesupported solid slab. Twoway flat plate concrete floor system design structurepoint. Twoway restrained slab if the slabs consist more than one panel or corner of the slab are prevent against lifting it is define as twoway restrained slab. 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. 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. This example is to be used for educational purposes only. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only.
Bending will take place in the two directions in a dishlike form. The basic design procedure of a twoway slab system has five steps. These are the direct design method presented in chap. Twoway concrete slab with beams spanning between supports. One way slabs are those supported continuously on the two opposite sides so that the load sare carried along one direction only. Slabs are usually used in floor and roof construction. The slab has to carry a distributed permanent action of 1. Oneway and twoway slabs oneway slabs transfer the imposed.
They may be supported on two opposite sides only fig. The other ways of analysis of twoway slabs are the direct design method and the equivalent frame method. Comparison of oneway and twoway slab behavior oneway slabs carry load in one direction. 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.
Difference between one way slab and two way slab system. Design of a two way rcc slab structural engineering. Twoway slab design based on aci 31811 using finite element method. Design of reinforced concrete structures ii twoway slabs. The pca computer program pcaslab can be used to expedite the design of different slab systems. Design of slabtwo way excel sheet online civilforum. Design calculation for twoway slab civil engineering community. Two way slab design by direct design method as per aci 31811. Twoway flat plate concrete floor system analysis and design. The analysis and design follow the equivalent frame analysis method of the aci code, which considers a onebay wide strip of the floor system as a continuous frame. Summary and comparison of twoway slab design results.
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