Ndesign of two way slab as per is 456 pdf

The lsm uses a multiple safetyfactor format which attempts to. Specifications for design of footings as per is 456. However, twoway slabs prestressed with unbonded tendons are highly redundant and intrinsically provide alternate load paths in the event of a catastrophic event, which results in significant loss of tendons. For example, the minimum slab thickness for a twohour fire rating is 4. Abstractdesigning twoway slabs under transverse concentrated loads is one of the challenges in designing such structures. No certain method can be found in the design codes or references for designing twoway slabs subjected to concentrated loads. The main reinforcement for two way slab are designed in two directions which are xdirection and ydirection. Flanged beam sections comprise tbeams and lbeams where the slabs and beams are cast. Mukherjee, civil engineering, iitb structural analysis to determine the response of the structure under the action of loads. 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.

A six storey building for a commercial complex has plan dimensions as shown in figure 1. In case of oneway slab, the main reinforcement of the slab, span along the width of the room while the distribution bars, laid at right angles to the main reinforcement, lie parallel to the length of the room. In twoway slabs shorter direction strip carry greater %age of load. Design of one way slabs as per is 456 worked step by. Design of reinforced concrete structures ii twoway slabs.

In a test of a ninepanel, two way, unbonded posttensioned slab performed at the university of texas in 1973 reference 2. The one way slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Response may be displacement, internal forces like axial force, bending moment, shear force etc. Find the dead load and the live load per square meter of the slab. Oneway and twoway slabs oneway slabs transfer the imposed.

Design of two way slabs is 456 limit state method youtube. 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. Oneway and twoway slabs university of asia pacific. Ghali developments in yield line theory for slabs by w. There are two other considerations that a sensible designer ought to bear in mind. Design of two way slabs this symposium publication consists of 10 papers that give the designer an overview of some of the different analysis and design techniques currently being used.

Design of a two way rcc slab structural engineering forum. Reinforced concrete slab design and detailing guidelines for depth of slab, loads on slab, reinforcement guide for oneway and twoway slabs as per is. Twoway flat slab concrete floor with drop panels system analysis and design design the concrete floor slab system shown below for an intermediate floor considering partition weight 20 psf, and unfactored live load 60 psf. Design tables 2 way slabs as per is 456 with deflection check.

Jul 09, 20 design of rcc rectangular slabs as per is 4562000 the design of two way rectangular slabs supported on all four sides without provision for torsion at corners is carried out as per table 27, indian standard is 456 app. Design of reinforced concrete structures ii twoway slabs 1 1. However, two way slabs prestressed with unbonded tendons are highly redundant and intrinsically provide alternate load paths in the event of a catastrophic event, which results in significant loss of tendons. 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. Finally, since shear reinforcement is not used in oneway slabs, the concrete must be able to resist the maximum shear force. Distribute moments transverse at critical sections to column and middlestrip and if.

Analysis of two way ribbed and waffle slabs with hidden beams. Downloads code design of cantilever slab as per is 456. Under the general provisions of the 1995 code, chapter, the twoway joist portion may be combined with a solid column head or with solid wide beam sections on the column centerlines for uniform depth construction. Design the building for seismic loads as per is 1893 part 1. Two way rcc slab designing excel sheet civil engineering. It deals with the problem of openings in twoway concrete slabs.

The total load of twoway slab loaded with uniformly distributed load and supported on all the four edges is assumed to be transmitted to the supporting walls or edge beams in the manner as shown in fig. The oneway slab is deflected in one way direction and primary reinforcement is placed in one direction whereas. Analysis and design of slabs two way civil engineers pk. Assume the thickness of slab take 4 cm per metre run of the span. Design of reinforced concrete structures ii two way slabs 1 1. Feb 07, 2018 combined footings for two columnscombined footings for two columns the term combined footings is usually used for one footingthe term combined footings is usually used for one footing which is designed to carry the loads of two separate columns. Twoway flat slab concrete floor with drop panels system. Similarly any horizontal projections as the balconies or the cantilevers. In a test of a ninepanel, twoway, unbonded posttensioned slab performed at the university of texas in 1973 reference 2.

The building is located in seismic zone iii on a site with medium soil. In case of one way slab, the main reinforcement of the slab, span along the width of the room while the distribution bars, laid at right angles to the main reinforcement, lie parallel to the length of the room. If the length to breadth ratio of the room is less than 2, the slab is designed as a twoway reinforced slab. Determine the maximum bending moment for a one meter wide strip of the slab. No redistribution is allowed when method 1 or method 2 of analysis in section 3. Rectangular beams and oneway slabs page 3 of 9 design of rectangular beams and oneway slabs continued a. Design of two way slab by is 456 building materials.

Design of a two way rcc slab structural engineering. Design of one way slabs as per is 456 worked step by step. Load calculation dead load knm2 wall load main knm s. Civilax based to server in civil engineering provides etabs and sap2000 tutorials, civil engineering spreadsheets, civil engineering ebooks and many more civil engineering downloads.

Dec 14, 2017 design of one way slab is covered in this video. Flanged beam sections comprise tbeams and lbeams where the slabs and. Usually balcony slabs are cantilever slab and hence a provision for wall load at free end is included so that the spread sheet is useful for practical purposes. Reference 5 focused on analysis of two way ribbed slabs with.

Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. Difference between one way slab and two way slab system. Limit state method study notes for civil engineering. Bending moment and shear force of two way slab are depend on l y l x ratio and. These slabs are constructed to provide flat surfaces, usually horizontal, in building floors, roofs or other types of structures.

Flat slab system is an important division of concrete floor system. Accordingly, main reinforcement is required in the two directions. Lylx factored dead load factored live load total factored load table shown is as per table 22 of is. Feb 14, 2017 design tables 2 way slabs as per is 456 with deflection check 1. Twoway slabs, design of twoway slabs, sp183 engineering. Reinforced concrete slab design and detailing guidelines for depth. 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. Design of two way slab by is 456 free download as excel spreadsheet. The ratio of length to width of one slab should less than 2 otherwise oneway action is obtained, even though supports are provided on all sides. Slabs are usually used in floor and roof construction.

Two way slabs have two way bending unlike one way slab. Two way reinforced concrete slab design clear longer span of slab please enter the longer span. The ratio of the total costs was found to be within the range 1. Please read the lauses mentioned in the video while solving the problem. Structure geometry and material properties are known.

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. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. Following are the rcc slab design and detailing guidelines. Footings is designed to sustain the applied loads, moments and forces and the induced reactions and to ensure that any settlement which may occur is as nearly uniform as possible, and the safe bearing capacity of the soil is not exceeded see is 1904. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place.

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. Twoway slabs are surface members acting in a both directions. In a two way slab the slab has to resist the following forces. 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. In many cases the slabs are of such proportions and are supported in such way that twoway action. Check for deflection is as per the provsions in cl. Design of rcc rectangular slabs as per is 4562000 the design of two way rectangular slabs supported on all four sides without provision for torsion at corners is carried out as per table 27, indian standard is 456 app. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types. The total load of two way slab loaded with uniformly distributed load and supported on all the four edges is assumed to be transmitted to the supporting walls or edge beams in the manner as shown in fig. The basic design procedure of a two way slab system has five steps. Krauthmmer design for punching shear in concrete by s. Load transfer in a oneway slab, b twoway slab nilson fig. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. Slab shear strength twoway shear check the adequacy of slab thickness for punching shear twoway shear at an interior column figure 4.

Bending will take place in the two directions in a dishlike form. In this video deisgn of two way slabs has been covered using is 456. Find the effective span which is lesser of i distance between centres of bearings, and ii clear span and effective depth. Nov 12, 2015 design of a structural member is governed by what kind of forces it has to resist. The other ways of analysis of twoway slabs are the direct design method. Example seismic analysis and design of a six storey building problem statement. 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.

Design tables 2 way slabs as per is 456 with deflection check 1. Pdf slabs are the flooring systems of most structures including office, commercial. Generally, there are two types of slab which are one way and two way slabs. Two way slab design by direct design method as per aci 31811. Chapter 3 design of rectangular beams and oneway slabs 12. For designing two way slab refer is code 4562000 and sp16. The slab is assumed to be divided into two triangles and two trapeziums by lines, ap. Ce 403, fall 20 oneway slab design 3 4 aci 31811 referenced pp 2 4 rating. I have developed a microssoft excel software for design of a two way rcc slab. The lateral loads are independently resisted by shear walls. Twoway slabs have two way bending unlike oneway slab. Therefore, other design values can be reduced according to the. This spread sheets is useful for design of cantilever slab as per is 456. This condition occur when the slab are supported at four side of the beams or walls and the ratio of long span to short span is equal or less than 2.