Bending will take place in the two directions in a dishlike form. Design of two way slabs is 456 limit state method youtube. A waffle slab or twoway joist slab is a concrete slab made of reinforced concrete with concrete ribs running in two directions on its underside. A six storey building for a commercial complex has plan dimensions as shown in figure 1. So, main reinforcement is provided in both direction for two way slabs. Chapter 3 design of rectangular beams and oneway slabs. Concrete 3 design of concrete beam and slab twoway slab. Here the ratio of longer span of slab to the shorter span of slab is less or equals to 2. View test prep concrete 3 design of concrete beam and slab twoway slab part 22 from engineerin 101 at royal melbourne institute of technology.
In one way slab, the slabs are supported by the beams on the two opposite sides. Fanella, which appeared in the october 2001 edition of structural engineer magazine. Analysis and design of slabs two way two way edge supported slabs two way slabs. Reinforced concrete design to bs8110 structural design 1 lesson 5 6 4. Design of slab examples and tutorials by sharifah maszura syed mohsin. For those who do not know what are the des ign requirements of a slab. It is used where the supporting soil has low bearing capacity. They may be supported on two opposite sides only fig. Design of a two way rcc slab structural engineering. Design of matraft foundation mat or raft foundation is a large concrete slab supporting several columns in two or more rows. Comprehensive and customizable reports are available for all analysis and design results. There are many methods that are used to analyze two way slabs and the precision of these methods vary depending. Design of a two way rcc slab structural engineering forum. Since the design of steel deck floor slabs is primarily based upon the loadcarrying characteristics in a oneway direction parallel to the deck corrugations, the performance tests are performed on oneway slab elements see fig.
I have developed a microssoft excel software for design of a two way rcc slab. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Pdf the article is about design of prestressed slabs. In twoway slabs shorter direction strip carry greater %age of load. 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. 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. I think you should look at a concrete textbook my favorite is wang and salmons reinforced concrete design and read the chapter on design of two way floor systems. Analysis of two way slab structural engineering general. The following example illustrates the example building. Analysis and design of slabs two way civil engineers pk. The procedure carried out for modeling and analyzing the. Missouri university of science and technology scholars mine. Twoway slabs structural engineering forum of india, sefi. Handbook on good building, design and construction in the.
In one way slab, the loads are carried along one direction. In this video deisgn of two way slabs has been covered using is 456. The first reinforced concrete design manual formerly titled aci design handbook was developed in. These conditions are set out in last section dealing with oneway ribbed slabs. Advanced slab design mode enables concrete slabs defined with or without holes to be designed using the ramconcept or adaptbuilder software. Design of reinforced concrete structures ii twoway slabs 1 1. The building is located in seismic zone iii on a site with medium soil. Alternate design method design procedure of twoway slabs. Jul 02, 2010 lecture series on design of reinforced concrete structures by prof.
Analysis of two way ribbed and waffle slabs with hidden beams. In two way prestressed slabs, many designers also provide a nominal grid of nonprestressed reinforcing steel typically no. Rectangular beams and oneway slabs page 2 of 9 two methods. Based on the stiffness requirement assume suitable depth and calculate the effective span.
Check for deflection same method as two way slab allowable spand eff. 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. Design of reinforced concrete structures ii two way slabs 1 1. A civil engineer must know all the aspects regarding the flat floor system. One way slab design procedure with example design of one. Determine the line of action of the resultant of all the loads. Distribute moments transverse at critical sections to column and middlestrip and if. 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 being supported on four sides the load will be carried in both the directions. For the design of columns and beams frame analysis is done by limit state method to know the moments they are acted upon.
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. Determine moments at critical sections in each direction, normally the negative moments at. This paper focuses on analysis of two way ribbed and waffle slabs with hidden beams. The oneway slab is deflected in one way direction and primary reinforcement is. Moments for design may be taken from table 3 for slabs simply supported on four sides.
Direct design method ddm and the equivalent frame method efm are. This method was provided in the american concrete institute aci in 1963 to design twoway slabs carried by steel beams, deep beam, or walls. A monolithic reinforced concrete floor is to be composed of rectangular bays measuring, as shown. Posttensioned and reinforced concrete slab and beam. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. A brick wall of 250 mm thickness including plaster of 1. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. The name waffle comes from the grid pattern created by the reinforcing ribs.
Two way rcc slab designing excel sheet civil engineering. Calculate factored moment and shear force by considering the onemeter width of the slab. This condition occur when the slabs are connected monolithically with support. Two way slabs are normally supported from four sides. The basic design procedure of a twoway slab system has five steps. Finally, calculate reinforcement area, then number of bars and their spacing. Twoway slab analysis and design using equivalent frame method efm aci 318 states that a slab system shall be designed by any procedure satisfying equilibrium and geometric compatibility, provided that strength and serviceability criteria are satisfied. Finite element design without strips is also available and useful for slabs with complex geometries. One way and twoway slabs one way slabs transfer the imposed loads in one direction only. Oneway and twoway slabs oneway slabs transfer the imposed. Two way slab design by direct design method as per aci 31811. The first is an approximate method known as the direct design method, and the second which i prefer is the equivalent frame method. Twoway slab design based on aci 31811 using finite element method.
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. 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. There are several methods by which two way slabs can be designed. Flat plate concrete floor system does not use beams between columns or. Reinforced concrete design to bs8110 structural design 1. Here are the steps for the design procedure for one way slab in steps. Flat slab analysis, design and detailing pdf civil.
Dec 20, 2017 in this video deisgn of two way slabs has been covered using is 456. Mention the parameters governing slab moment coefficients and explain their effects on moment. Twoway slabs have two way bending unlike oneway slab. A civil engineer should study these lectures and materials for structural engineering acumen. The ratio lb which is less than 2 is known as two way slab.
Dhang, department of civil engineering, iit kharagpur. Flat slab analysis, design and detailing pdf flat slab system is an important division of concrete floor system. Please read the lauses mentioned in the video while solving the problem. When the ratio of long span to short span is less than 2, then the slab is known as a slab spanning in two directions or twoway slab. Accordingly, main reinforcement is required in the two directions. Analysis of two way ribbed and waffle slabs with hidden beams article pdf available in international journal for computational civil and structural engineering volume 4, no 3, 2014 january. Good building design and construction handbook page 4 forewords yiping zhou director special unit for southsouth cooperation, undp good building design and construction. In two way slab, the slabs are supported on all the four sides. When the ratio of long span to short span is less than 2, then the slab is known as a slab spanning in two directions or two way slab. Waffle slabs are preferred for spans greater than 40 feet 12 m, as they are much stronger than flat slabs, flat slabs with drop panels, twoway slabs, oneway slabs, and. For two way slab systems you have the option of modeling the structure either using the equivalent frame method efm or simple frame method sfm. These materials are originally located at different websites. In two way slab, the ratio of longer span l to shorter span b is less than 2.
In two way slabs, load will be carried in both the directions. Design procedure of twoway slabs using aci moment coefficients. Two way slabs are such slabs in which the loads are shared by both the shorter and longer direction of the slab. Reinforced concrete design 1 design of slab examples. Slabs are usually used in floor and roof construction. Alternate design method design procedure of twoway slabs using aci moment coefficients and approved by bnbc 20 scope and limitations bnbc 6. 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.
Difference between one way slab and two way slab simple. The following example illustrates the design methods presented in the pca book simplified design. Two way slabs have two way bending unlike one way slab. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. Analysis and design of one way and two way slab in staad.
Design procedure steps for one way slab slab design steps. Chapter 3 design of rectangular beams and oneway slabs 12. Two way slab being supported on four sides the load will be carried in both the. The reinforced concrete design manual sp1711 is intended to provide guidance and assistance to professionals engaged in the design of castinplace reinforced concrete structures. Oneway and twoway floor systems and beam frames multiple beam crosssections. This is a part of his project economic design of two way rcc slabs under prof s. Example design of two way edgesupported solid slab. Twoway concrete slab with beams spanning between supports. The design bending moment of twoway restrained slab can be calculated as follows.
Difference between one way slab and two way slab daily civil. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in. Efm is the most comprehensive and detailed procedure provided by the aci 318 for the analysis and design of twoway slab systems where the structure is. Flat slab analysis, design and detailing pdf civil engineering. Twoway flat plate concrete floor system design structurepoint. It shows possible solutions of two way prestressed floors depending on different factors. One way and two way slabs one way slabs transfer the imposed loads in one direction only. 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. These types of slabs are used in constructing floors of multi storeyed building. Plan view of floor system assume partitions will not be damaged by deflections. Carry out analysis step 2 moment envelope sk 29 typical moment envelope.
Oneway and twoway slabs university of asia pacific. Abcd is a two way slab lb concrete specify the design parameters click on commands select design slabelement and assign it to the required plate elements. Two way posttensioned slabs with unbonded tendons offer further advantages in the prevention of local or. Slab resting on walls or sufficiently deep and rigid beams on all sides. Generally, there are two types of slab which are one way and two way slabs. What is the formula for taking load from two way slab for. Design of reinforced concrete components of a house. Nonetheless, the coefficient method is not included in the current edition of the aci code. 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. Summary and comparison of twoway slab design results. One way slab is supported by two parallel beams or walls. Compute positive and negative moments in each direction. I am submitting it to you and i want students or professional engineers to download it and use it for their studies or projects. Reinforced concrete design 1 design of slab examples and.
Detailed plans, sections, elevations, schedules, and tables may be generated, viewed, and printed from within safe or exported to cad packages. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types. 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. 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. Summary of bill of quantities civil works bar bending schedule. Oct 27, 2016 difference between one way slab and two way slab. Slab designing is done depending upon the type of slab one way or two way, end conditions and the loading. Design procedure the basic design procedure of a two way slab system has five steps.
Load transfer in a oneway slab, b twoway slab nilson fig. Bending will take place in the two directions in a dishlike fo. Analysis and design of slabs one way civil engineers pk. Beams of width and depth are provided on all column lines. The general provisions for construction and design procedure are given in cop 20. 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. Flat slab analysis and design pdf flat slab design pdf 1. Design of reinforced concrete structures ii twoway slabs. The slab has to carry a distributed permanent action of 1. Pdf design of twoway prestressed slabs researchgate. All methods are viable provided that the safety and serviceability of the elements are within the acceptable limits. For twoway slab systems you have the option of modeling the structure either using the equivalent frame method efm or simple frame method sfm.
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