The ratio of the total costs was found to be within the range 1. 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. Second thing is that i want a similar sheet for designing of one way slab. Application of lb ratio in first figure slab is supported on two opposite sides only. Accordingly, main reinforcement is required in the two directions. Oneway slabs transfer the imposed loads in one direction only. Twoway concrete floor slab with beams design and detailing csa a23.
Twoway concrete slab with beams spanning between supports. Interior bay dimensions 20 24 this example is to be used for educational purposes only. The following example illustrates the example building. Oneway and twoway slabs university of asia pacific. Twoway joist concrete slab floor waffle slab system. They may be supported on two opposite sides only fig. The pca computer program pcaslab can be used to expedite the design of different slab systems. Slab shear strength twoway shear check the adequacy of slab thickness for punching shear twoway shear at an interior column figure 4. Use the aci 318 direct design method to design an interior bay of a flat plate slab system of multi bay building. Here are the steps for the design procedure for one way slab in steps. Plan view of floor system assume partitions will not be damaged by deflections. Two way slabs have two way bending unlike one way slab. Slab moments calculated by various slab analysis methods are compared with each other for idealized flatplate and twoway slabonbeam structures. Design of reinforced concrete structures ii twoway slabs 1 1.
Pdf slabs are the flooring systems of most structures including office. This is a part of his project economic design of two way rcc slabs under prof s. Flat slab analysis, design and detailing pdf civil. No certain method can be found in the design codes or references for designing twoway slabs subjected to concentrated loads.
Twoway slab example 1 beam structure classical mechanics. Shear strength of two way slabs shear failure occurs when inclined cracks form due to flexural and shearing stresses. These are the direct design method presented in chap. For those who do not know what are the des ign requirements of a slab. Two way slabs prestressing tendons cgs at top 48 mm at bottom 48 mm nonprestressing reinforcement cover at top 25 mm at bottom 25 mm 143 design criteria 143. Distribute moments transverse at critical sections to column and middlestrip and if. The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas the twoway. Reinforced concrete slab slabs are plate elements forming floors, roofs in buildings. Two way rcc slab designing tool in microsoft excel developed by shankar tayal a 3rd year student of school of infrastructure, indian institute of technology, bhubaneswar this is a part of his project economic design of two way rcc slabs under prof s.
This design example was edited in 2012 by hdr engineering, inc. 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. This latter requirement imposed certain constraints. In twoway slabs shorter direction strip carry greater %age of load. 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. Cross sectional constant defines torsional properties c x. Design procedure steps for one way slab slab design steps. Moduleiii design of short and long columns with axial and eccentric loading, design of isolated column footing. Analysis and design of slabs two way civil engineers pk. 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. 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. Slab resting on walls or sufficiently deep and rigid beams on all sides. Many of these earlier design aids intended to carry out relatively simple design calculations were eliminated in the sp1709 edition. 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 2688 venado way rescue, ca 95672 phone.
Oneway spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. I had downloaded that sheet from internet so even i dont know the password of it. All available load test results indicated that the flat plate or flat slab was a most efficient design with an adequate safety factor.
Rectangular beams and oneway slabs page 2 of 9 two methods. Load transfer in a one way slab, b two way slab nilson fig. Oneway slab design spreadsheet civil engineering community. Twoway concrete slab on beams floor analysis and design. Reference 5 focused on analysis of twoway ribbed slabs with. The explicit transverse torsional member method is found to give good results for drifts and slabbeam actions, and is recommended for analysis and design of twoway slab systems under combined. Design of oneway slabs the structural action of a oneway slab may be visualized in terms of the deformed shape of the loaded surface. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types. The basic design procedure of a two way slab system has five steps. Twoway slabs have two way bending unlike oneway slab. Two way slab is a slab in which the ratio of longer side to the shorter side is less than or equal to two. Flat slab analysis, design and detailing pdf civil engineering. Design the building for seismic loads as per is 1893 part 1.
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. The program covers wide range of twoway slab systems and can be used for more complex slab layouts. Abstract the purpose of this example is to illustrate the use of the aashto lrfd bridge design for the design of a continuous two span steel igirder bridge. The design bending moment of twoway restrained slab can be calculated as follows. Figure 1 shows a rectangular slab, simply supported along its two opposite long edges and free of any support along the two. Design of one way and two way slabs, design of staircases.
A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. 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. Reinforced concrete slab design using the empirical method. The 2012 edition of the reinforced concrete design manual sp1711 was developed in accordance. Slabs are usually used in floor and roof construction.
Time saving design aids twoway slabs page 6 of 14 the pca computer program pcaslab can be used to expedite the design of different slab systems. 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. Beams of width and depth are provided on all column lines. Aci 318 11 code provides two methods for two way slab design one of which is direct design method. Twoway slabs structural engineering forum of india, sefi. Abstractdesigning twoway slabs under transverse concentrated loads is one of the challenges in designing such structures. Reinforcement implementation, static and dynamic analysis for reasons regarding behaviour, safety and economical design, the twoway slab is far more efficient than the equivalent oneway slab. Design of a two way rcc slab structural engineering forum. Slab moments calculated by various slab analysis methods are compared with each other for idealized flatplate and two way slab onbeam structures. Two way rcc slab designing tool in microsoft excel developed by shankar tayal a 3rd year student of school of infrastructure, indian institute of technology, bhubaneswar. Learning outcomes at the end of this lecture, the student should be able to a classify all types of solid slabco1 b identify one way and two way solid slab co1 c use a relevant clauses in code of practice co1 d design oneway slabs co2 e details the slabsco1. The unit weight of reinforced concrete is assumed to be 24 knm3. Pdf analysis of two way ribbed and waffle slabs with. Bending will take place in the two directions in a dishlike form.
The procedure of the design of twoway slabs will have all the six steps mentioned in sec. Two way rcc slab designing excel sheet civil engineering. My graduation project with my mate ghassan faris, a two way ribbed slab of clear span of 18 x 25 m was designed by safe 2014, the building is 3storey concrete. 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. 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. Analysis and design of slabs two way twoway slabs have two way bending unlike oneway slab. The output of the program for the slab in the example is shown in the following pages. Example design of two way edgesupported solid slab. Reinforced concrete slab design and detailing guide is456.
One way slab oneway slabs are those slabs with an aspect ratio in plan of 2. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. In this video deisgn of two way slabs has been covered using is 456. 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. Figure 1 shows a rectangular slab, simply supported along its two opposite long edges and free of any support along the two opposite short edges. A six storey building for a commercial complex has plan dimensions as shown in figure 1. Chapter 3 design of rectangular beams and oneway slabs 12.
Aci 31811 code provides two methods for two way slab design one of which is direct design method. Allowable stress design or working stress design wsd 2. Jul 22, 2015 my graduation project with my mate ghassan faris, a two way ribbed slab of clear span of 18 x 25 m was designed by safe 2014, the building is 3storey concrete. Effective depth d span ldbasic x modification factor for obtaining modification factor, the percentage of steel for slab can be assumed from 0. What are the difference between tender and contract documents. Oneway and twoway slabs oneway slabs transfer the imposed. The two classifications are oneway slab and twoway slab. The procedure of the design of two way slabs will have all the six steps mentioned in sec. The program covers wide range of two way slab systems and can be used for more complex slab layouts. Nov 27, 20 one way slab oneway slabs are those slabs with an aspect ratio in plan of 2. Please read the lauses mentioned in the video while solving the problem. 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. Shear strength of beamless slabs usually a controlling factor.
Design of slabtwo way excel sheet online civilforum. 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. Explanatory text was added to each chapter, while maintaining relevant design aids and illustrative examples. The other ways of analysis of twoway slabs are the direct design method and the equivalent frame method. Civilax is the knowledge base covering all disciplines in civil engineering. Before going to this topic, please read it there are two types of slab classification based on the direction of bending occurs in these slabs. Slab shear strength two way shear check the adequacy of slab thickness for punching shear two way shear at an interior column figure 4. I know that this sheet is made using macro but i have no idea of using macro. This condition occur when the slabs are connected monolithically with support.
The general layout of the building is shown in figure 1. Load transfer in a oneway slab, b twoway slab nilson fig. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Design of reinforced concrete structures ii two way slabs 1 1. The basic design procedure of a twoway slab system has five steps. Therefore, primary reinforcement is presented in both directions for resisting the loads. Following are the rcc slab design and detailing guidelines. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. The dimensions of an interior bay are shown in figure 1. Design of one way slabs the structural action of a one way slab may be visualized in terms of the deformed shape of the loaded surface.
The following example illustrates the design methods presented in the pca book. 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. Tn342 design example 2way mondada 093090 adapt corporation. Two way slab design design of two way slab rc design. 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. This pdf file contains a chapter of 23 pages with various aspects of flat slabs including four example of flat slab design. At ground level, the floor beams fb are not provided, since the floor directly rests on ground earth filling and 1. However, plastic method can be the best method for designing such cases of twoway slabs. Detailing and design of earthquake resistant buildings made of reinforced concrete. For designing two way slab refer is code 4562000 and sp16. The explicit transverse torsional member method is found to give good results for drifts and slab beam actions, and is recommended for analysis and design of two way slab systems under combined.
The building is located in seismic zone iii on a site with medium soil. 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. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Design of reinforced concrete structures ii twoway slabs. Design of reinforced concrete structures ii twoway slabs 8 c. Two way slab design by direct design method as per aci 31811. Manual for the design of reinforced concrete building. Types of one way slab one way slab may be solid hollow ribbed 6. Generally, there are two types of slab which are one way and two way slabs. I have developed a microssoft excel software for design of a two way rcc slab. Example seismic analysis and design of a six storey building problem statement. 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. The numbering of the members is explained as below. The specified design strength of the concrete, is 25 mpa and the specified yield strength of the reinforcement, fy, is 400 mpa.
Dec 20, 2017 in this video deisgn of two way slabs has been covered using is 456. Design of a two way rcc slab structural engineering. Rectangular beams and one way slabs page 2 of 9 two methods. In two way slab, load is delivered in both the directions. Chapter 3 design of rectangular beams and oneway slabs.
Assume partitions cannot be damaged by deflections. I have an excel sheet for designing of two way slab but that sheet is password protected. 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. Aci318 code provides two design procedures for slab systems. Twoway concrete floor slab with beams design and detailing.
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