Pdf design calculation design of one way slab slab s1. Design of slab examples and tutorials by sharifah maszura syed mohsin example 2. The proposed slab system must meet the current code. Reinforced concrete design 1 design of slab examples and. Two way slabs are normally supported from four sides. For example, the minimum slab thickness for a twohour fire rating is 4. This paper focuses on analysis of two way ribbed and waffle slabs with hidden beams.
Analysis and design of slabs one way civil engineers pk. The largest shear stress at the support is found when the rst. Ce 403, fall 20 oneway slab design 2 4 aci 31811 referenced pp 2 4 typical concrete floor systems copied from ceco concrete construction pamphlet design procedure a oneway slab is designed by considering a onefootwide strip of slab. Design criteria there are three criteria which must be considered for the design of a conventional one way slab system.
Tayabji regional manager ctl group report 05320 1 project 05320. Lecture series on design of reinforced concrete structures by prof. Columns may be offset from the basic rectangular grid of the building by up to 0. Exterior columns when design is carried out using the direct design method, aci sec. Design of one way slabs as per is 456 worked step by. Pdf oneway slabs subjected to combination of loads failing in. Therefore, for the design problem under discussion, m lalb 1216 0. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3.
In two way slab, the ratio of longer span l to shorter span b is less than 2. These coefficients of beams are also applicable for the design of oneway slabs, based on linear elastic theory. Accordingly, main reinforcement is required in the two directions. Here ratio of longer span of slab to the shorter span of slab is greater than 2. Slabs having supports on less than four sides can be designed as one way. Pdf the paper presents the cost optimization of reinforced concrete simply supported oneway slabs under uniformly distributed load with the nonlinear. Analysis of two way ribbed and waffle slabs with hidden beams. One way slab being supported on two opposite sides only leads to the structural action in single direction. Define the term slab, one way slab, two way slab, shrinkage and temperature reinforcement, main reinforcement. One way slab design simplified online design of concrete.
If a one way slab is supported on more than two edges and its aspect ratio, i. Chapter 3 design of rectangular beams and oneway slabs 12. For 1m slab width, moment, shear force, one way continuous slab for continuous slab, moment and shear force can be obtained from table 3. Design procedure steps for one way slab slab design steps. Reinforced concrete, 2014, 9th edition, aci 31811 code edition, by jack c. This moment is used to compute the shear stresses due to moment transfer to the edge column, as shown in sec. Design of reinforced concrete structures ii two way slabs 1 1. Reinforced concrete slab design and detailing guide is456. Pdf oneway shear strength of thick slabs and wide beams.
Flat plate concrete floor system does not use beams between columns or. The slab deflects in both direction and the loads transferred in all four edges. Design of one way reinforced concrete slabs class notes and example notes on. The two classifications are oneway slab and twoway slab. Such slabs are designed as oneway slabs where the span length ln is equal to the length of short direction. The paper presents the cost optimization of reinforced concrete simply supported one way slabs under uniformly distributed load with the nonlinear programming approach. Twoway joist concrete slab floor waffle slab system. Pdf basic principles, theory and oneway slabs san patel. 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.
For one way slab, main reinforcement is computed by a formula in limit state design that is determined by comparing compressive force as well as tensile forces. Zollinger program manager, rigid pavements texas transportation institute and shiraz d. When the ratio of the length of a room to its breadth is greater than 2, most of the load is carried by the short span i. For those who do not know what are the des ign requirements of a slab. Slab slabs are an important structural component where prestressing is applied. A typical sixspan, oneway slab supported on beams,as occurs in parking structures is selected. One way simply supported slab analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. Minimum thickness for solid oneway slabs unless deflections are calculated for slab not supporting or attached to partitions or other construction likely to be deamaged by large deflection.
The codes governing the design of the one way slab will be aci 31802 and ibc 2003. Here are the steps for the design procedure for one way slab in steps. Ce 433, summer 20 slab design example 1 5 design a one. Successive span in each direction shall not differ by more than 1 3 the longer span. Best practices of concrete pavement transition design and construction by youn su jung graduate assistant research texas transportation institute dan g. Difference between one way slab and two way slab simple. Design of twoway floor slab system comparison of one. There are many methods that are used to analyze two way slabs and the precision of these methods vary depending. 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. In this article, i will discuss how to design one way slab with example. Lylx 1 as two way slab in our theoretical studies but in site they are using oneway slab reinforcement design cause of due to economic cost wise low and labour cost is low to compared with two way slab design so, in site all are mostly provided one way slab.
The load on the slab is carried by the short span in one direction. Design of reinforced concrete structures ii twoway slabs 1 1. One way simplysupported and continuous solid slab free download as powerpoint presentation. One way slab design criteria with design example according to aci code. Sometimes the minimum depth is adequate as per flexure design, but if deflection criteria arent fulfilled such slabs will face vibration even under small loads like walking, jumping, etc. Pdf experimental study of shear in reinforced concrete one.
Slab is a common term used to describe the structural elements such as floors and roofs where. Nowadays, access to powerful computers and advanced software gives possibility to create accurate models by means of the finite. The two classifications are one way slab and two way slab. Design of reinforced concrete structure one way slab presented by md. Rectangular beams and oneway slabs page 2 of 9 two methods. Design example of one way slab with detailing free download as pdf file. Design the slab following the provisions of the aci code. If slab is supported on all four sides and r shorter side longer side pdf from civil eng.
Jul 02, 2010 lecture series on design of reinforced concrete structures by prof. Design of slab examples and tutorials by sharifah maszura syed mohsin. If slab is supported on all four sides and r shorter side longer side way slab. Twoway concrete slabs with openings these problems cannot be solved by analytical methods since such structures like concrete slabs with openings, especially strengthened with carbon fibres, are too complicated. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. The corner reinforcement can be arrange in two way as shown below. May 02, 2017 chajjas and verandahs are an practical example of one way slab. Best practices of concrete pavement transition design and. 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. Post dtensioned concrete esign for aci 31808 herein describes in detail the various aspects of the posttensioned concrete. 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. Redistribution of 10% may be allowed when method 3 or method 4 is adopted.
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. Department of mechanics, materials and structures english. The lateral loads are independently resisted by shear walls. Finally, since shear reinforcement is not used in oneway slabs, the concrete must be able to. 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. While the basic expression for oneway shear in aci 31805 is the same for narrow beams, wide beams, and slabs, an engineer is permitted to design. The proposed slab system must be able to be constructed at a reasonable cost. Analysis and design of the slab similar to design of simply supported beam as indicate in the previous chapter. One way reinforced concrete slab 1 structures, mechanics and computer.
Chapter 3 design of rectangular beams and oneway slabs. One way slab reinforcement details daily civil engineering. This strip is designed basically as if it were a 12inchwide beam, t inches thick. Design of concrete structures 14th edition, 2009, by arthur h. Direct design method for twoway slab limitations on use of direct design method 3. 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. No redistribution is allowed when method 1 or method 2 of analysis in section 3. D mm d 105 mm loads on slab self weight of slab 3. Two way concrete slabs with openings these problems cannot be solved by analytical methods since such structures like concrete slabs with openings, especially strengthened with carbon fibres, are too complicated.
A reinforced concrete slab is built integrally with its supports and consists of equal span of 15 ft. Continuous one way slab figure 1 shows a clear area of 12 m x 8. One way slab is supported by two parallel beams or walls. You should look at the bar diameter and spacing in the table displayed next to the graphical viewer or at fi16 400 mm on the description of the reinforcement bar in this zone instead as this is the actual area of the provided reinforcement. Introcduction slab in which the deflected surface is predominantly cylindrical termed as oneway slabs spanning in the direction of curvature. 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. Oneway and twoway slabs university of asia pacific. Design of one way slab usd one way slabs are those slabs having supports along one way only figure 1 a or slabs having supports having on all sides but with an aspect ratio in plan of 2. Determine moments at critical sections in each direction, normally the negative moments at supports and positive moment near midspan. Oneway and twoway slabs oneway slabs transfer the imposed. Pdf design calculation design of one way slab slab s1 span. Assume partitions cannot be damaged by deflections. Bending will take place in the two directions in a dishlike form.
Sometimes the minimum depth is adequate as per flexure design, but if deflection criteria arent fulfilled such slabs will face vibration even. One way slab design procedure with example design of one. Design of reinforced concrete structures ii twoway slabs. Oneway slab supported on beams the objective of this tutorial is to demonstrate the stepbystep procedure of adapt pt to analyze and design a posttensioned continuous slab supported on parallel beams or walls. Reinforced concrete design 1 design of slab examples. For 1m slab width, moment, shear force, oneway continuous slab for continuous slab, moment and shear force can be obtained from table 3. One way slabs are such slabs in which the loads are shared only by the shorter direction of the slab. One way spanning slabs should be treated as beams of unit width and chapter 2 should be followed except for minimum shear reinforcement. Design of one way slab usd oneway slabs are those slabs having supports along one way only figure 1 a or slabs having supports having on all sides but with an aspect ratio in plan of 2. Design example of one way slab with detailing scribd. Allowable stress design or working stress design wsd 2. Twoway joist concrete slab floor waffle slab system analysis and design design the concrete floor slab system shown below for an intermediate floor with partition weight of 50 psf, and unfactored live load of 100 psf. Distribute moments transverse at critical sections to column and middlestrip and if.
Minimum depth of the oneway concrete slab, most of the times is governed by deflection criteria. The basic design procedure of a two way 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 slab is supported on beams of size 225 x 500 mm spaced at 4. Please enter the practically physible spacing for main steel of two way slab based on summary. The following simplified design is valid when length2width of slab and for 15ft or 4. The basic design procedure of a twoway slab system has five steps. Slab support condition solid slabs continuous at one end solid slabs continuous at both ends simple span solid slabs cantilever. One way slabs are those supported on two opposite edges. Introcduction slab in which the deflected surface is predominantly cylindrical termed as one way slabs spanning in the direction of curvature. The slab has to carry a distributed permanent action of 1. Following are the rcc slab design and detailing guidelines. The ratio lb which is less than 2 is known as two way slab.
Dhang, department of civil engineering, iit kharagpur. Step 2 design forces draw panel of slab and indicate maximum design moments, shears and in. Reinforced concrete slab design and detailing guidelines for depth of slab, loads on slab, reinforcement guide for oneway and twoway slabs as per is. Design of oneway slabs check if it is oneway slab system if clear span in one direction, l1, is greater than or equal to two times the clear span in other direction, l2, then it is. However main reinforcement bar and distribution bar. The 2012 edition of the reinforced concrete design manual sp1711 was developed in accordance with the design provisions of aci 31811, and is consistent with the format of sp1709. Rectangular beams and one way slabs page 2 of 9 two methods. The design uses the program adapt floor pro release 20092010 featuring the hong kong code. A 2 2area 2 a c 2 2 posttensioned concrete design table 1 1 list of symbols used in the aci 31808 code cp area enclosed by the outside perimeter of the section, in a g gross area of concrete, in. When a slab is supported on all four sides and the ratio of long span to short span is equal or greater than two, it will be considered as one way slab. 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. They may be supported on two opposite sides only fig.
Ce 403, fall 20 oneway slab design 3 4 aci 31811 referenced pp 2 4 rating. Direct design method ddm for slab systems with or without beams loaded only by gravity loads and having a fairly regular layout meeting the following. Please select the grade of concrete for twoway slab construction. Pdf cost optimum design of reinforced concrete simply.