One way slab and two way slab pdf

One way slab here i solve a probleam based on the one way slab, the diamentions are provided in the probleam 1st determine the aspect ration and with respect to. Design of slab examples and tutorials by sharifah maszura syed mohsin example 1. Analysis and design of slabs one way civil engineers pk. Two way slabs are normally supported from four sides. Bending moment and shear force of twoway slab are depend on l y l x ratio and. One way slab is supported by beams in only 2 sides. Application of lb ratio in first figure slab is supported on two opposite sides only. If the ratio of longer dimension of the slab panel to the shorter dimension is greater than or equal to 2 then it is designed as one way slab. The ratio of longer span panel l to shorter span panel b is equal or greater than 2. Two way slab being supported on four sides the load will be carried in both the directions. Oneway slab is the most basic and common type of slab. If less than 2 then it is designed as a two way slab. Comparison of oneway and twoway slab behavior economic choices. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only.

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. The basic design procedure of a twoway slab system has five steps. 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. However main reinforcement bar and distribution bar in transverse direction. In reality, sandwich slabs are ribbed slabs with a slab placed both to their upper and lower surface. My name is sl khan and you are watching an engineer boy. Ce 403, fall 20 oneway slab design 3 4 aci 31811 referenced pp 2 4 rating. The ration of longer span pannel l to shorter span panel b is equal or greater than 2 thus lb 2. Thus, lb two types of slab classification based on the direction of bending occurs in these slabs. Edge supported two way slabs free pdf file sharing. So how do you differentiate a oneway and twoway slab. Introduction in reinforced concrete construction, slabs are used to provide flat, useful surfaces.

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. And its depend upon the condition of the structure design and longer to shorter span. The slab has to carry a distributed permanent action of 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. What is the difference between one way and two way slab.

Types of one way slab one way slab may be solid hollow ribbed 6. A two way slab has the main load carried in both directions. Reinforcement detailing of reinforced concrete slabs. The oneway slab is a slab, which is supported by parallel walls or beams, and whose length to breadth ratio is equal to or greater than two and it bends in only one direction spanning direction while it is transferring the loads to the two supporting walls or beams, because of its geometry. In this paper the cost optimization of reinforced concrete twoway slabs under uniformly distributed load with the nonlinear programming approach has been presented and it is a continuation of the. 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 basic difference between these slabs are oneway slab bends only in one direction and twoway slab bends in two directions as shown in the below figure. In two way slab, the ratio of longer span l to shorter span b is less than 2. Good morning, there are lots of advantages of one way slab and two way slab. Deep ribs, the concrete and steel quantities are relative low expensive formwork expected. But before that i had written a answer of one another question requested by someo.

Pdf cost optimum design of reinforced concrete simply. Corners of the twoway slab lift up if the slab is not cast monolithically with the supports wallsbeams. They may be supported on two opposite sides only fig. Here are the steps for the design procedure for one way slab in steps. For those who do not know what are the des ign requirements of a slab. Finally, since shear reinforcement is not used in oneway slabs, the concrete must be able to resist the maximum shear force. Pdf transition from oneway to twoway shear in slabs. Difference between one way slab and two way slab simple. Analysis and design of twoway slabs page 1 chapter 3.

A bentup bar called as crank bar is provided to make rcc slab safe from compressive stresses. If slab is supported on all four sides and r shorter side longer side of twoway slabs by gerald c. Mainly shorter span is carring larger load than longer span. 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. Load transfer in a oneway slab, b twoway slab nilson fig.

The basic difference between one way and two way slab is load distribution which is depends on support condition and span lengths. Design of oneway slabs the structural action of a oneway slab may be visualized in terms of the deformed shape of the loaded surface. A reinforced concrete slab is a broad, flat plate, usually horizontal, with top and bottom surfaces parallel or nearly so. Two way slabs are such slabs in which the loads are shared by both the shorter and longer direction of the slab. The main reinforcement for twoway slab are designed in two directions which are xdirection and ydirection.

The actual structural support of a one way slab is found on the shortest spans. One way and two way slab design aspect online civilforum. Usually, when a slab is supported by a beam the support is considered to be pinned. Oneway and twoway slabs oneway slabs transfer the imposed. One way and two way slab design aspect the slab provides a horizontal surface and is usually supported by columns,beams or walls. According to the way loads are transferred to supporting beams and columns, slabs are classified into two types. Mention the parameters governing slab moment coefficients and explain their effects on moment. The main supports are found going in both directions. To determine if the slab is two way, figure the ratio between the longer span and the shorter span. Define the term slab, one way slab, two way slab, shrinkage. Here the ratio of longer span of slab to the shorter span of slab is less or equals to 2. 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 procedure steps for one way slab slab design steps. Behavior and reinforcement of oneway slab the structural frame consists of four columns, two beams and one slab. Oneway and twoway slabs university of asia pacific. Figure 1 shows a rectangular slab, simply supported along its two opposite long edges and free of any support along the two. Difference between one way slab and two way slab daily civil. The first two systems consist of a concrete slab supfilename.

Verandah slab is a type of one way slab, where the slab is spanning in the shorter direction with main reinforcement and the distribution of reinforcement in the transverse direction what is two way slab. The longstanding problem of shear in structural concrete elements is typically studied as oneway shear in beams, or as twoway shear in slabcolumn connections. Comparison of oneway and twoway slab behavior economic choices oneway slab on beams suitable span 3 to 6m with ll 35knm2. Learning outcomes at the end of this lecture, the student should be able to a classify all types of solid slab co1 b identify one way and two way solid slab co1 c use a relevant clauses in code of practice co1 d design one way slabs co2 e details the slabs co1. The two classifications are oneway slab and twoway slab.

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. Reinforced concrete design 1 design of slab examples. The problem of oneway shear in slabs, as encountered by bridge engineers when. The twoway slab will deflect in a dish or saucerlike form under the action of loads. Flat plate for relatively light loads as in apartments or offices suitable span 4. Powered by the equivalent frame method of analysis and design per latest american aci 31814 and canadian csa a23.

Assume partitions cannot be damaged by deflections. Slabs are usually used in floor and roof construction. Simply supported one way slab a rectangular reinforced concrete slab is simplysupported on two masonry walls 250 mm thick and 3. The twoway slab s1 is supported by four beams twoway slab behaviour the behavior of a twoway slab is similar to that of a oneway slab the only difference being that now the slab loads will be carried in both directions.

Main reinforcement is provided in only one direction for one way slabs. The ratio of longer span panel l to shorter span panel b is less than 2. Oneway slabs, slab beam interaction, finite element analysis, regression analysis. Two way slab is supported by beams in all four sides. The three basic types are one way slabs, two way edge supported slabs and pointsupported slab systems.

Distinction of twosystems from one way systems is given by aci 31814 r8. One way slab is supported by two parallel beams or walls. One way slab oneway slabs are those slabs with an aspect ratio in plan of 2. Design of twoway floor slab system comparison of oneway and.

In two way slabs, load will be carried in both the directions. A rectangular reinforced concrete slab is simply supported on two masonry walls 250 mm thick and. One way slab is a slab which is supported by beams on the two opposite sides to carry the load along one direction. The load on the slab is carried by the short span in one direction. The twoway slab is designed for both the directions as it bends in both directions. What are the advantages of one way slab and two way slab. 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. When a reinforced concrete slab is 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. For example, the minimum slab thickness for a twohour fire rating is 4.