Cantilever slab design calculation

Design a cantilever projecting out from a room slab extending 1. A brick wall of mm thickness including plaster of 1. Analysis and Design of Slabs. You can get the latest information by subscribing to our posts. There are plenty of books available on our site related to structural design of all these things …. You can download them by becoming our member Thanks.

Is there any computer application and turoria for design like orion18, stapro, prokon etc i really want to know it and i need someone to teach me. Your email address will not be published. Notify me of new posts by email. A reinforced slab is a broad, flat plate, usually horizontal, with top and bottom surfaces parallel or nearly so.

Analysis and Design of Slabs It may be supported by reinforced concrete beams and is usually cast monolithically with such beamsby masonry mosaic glue by reinforced concrete walls, by steel structural members, directly by columns, or continuously by ground.

Analysis and Design of Slabs Slabs having supports on less than four sides can be designed as one-way. Calculate hmin and round it to higher 10mm multiple. Not less than mm for rooms ii. Not less than 75 mm for sunshades. Calculate dead load acting on the slab. Calculate live load acting on the slab. For -ve steel see how much steel is already available. Provide remaining amount of steel.

Check the slab for shear. Requesting for information on design of slabs, timber, retaining structures and so forth. Leave a Reply Cancel reply Your email address will not be published.

Sorry, your blog cannot share posts by email.Cantilever slabs are common features in buildings due to the need to have bigger spaces at upper floors.

To achieve this, architects normally extend the slab beyond the ground floor building line, thereby forming a cantilever. In this post, we are going to show how we can analyse and design cantilever slabs subjected to floor load and block work load. Solved Example A cantilever slab mm thick is 1. Design the slab using the data given below.

cantilever slab design calculation

Exercise for Students 1 Provide distribution bars 2 Verify the section for shear 3 Check for cracking 4 Do the detailing sketches. Save my name, email, and website in this browser for the next time I comment. Structville is a media channel dedicated to civil engineering designs, tutorials, research, and general development.

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Structural Design and Detailing Standards in Nigeria. Structural Design of Corbels. Vibration Serviceability of Composite Slabs. Thanks for the information very useful and informative. Please enter your comment! Please enter your name here. You have entered an incorrect email address!This tool calculates the static response of cantilever beams under various loading scenarios.

The tool calculates and plots diagrams for these quantities:. Please take in mind that the assumptions of Euler-Bernoulli beam theory are adopted, the material is elastic and the cross section is constant over the entire beam span prismatic beam. Calculate the moment of inertia of various beam cross-sections, using our dedicated calculators. The cantilever beam is one of the most simple structures.


It features only one support, at one of its ends. The support is a, so called, fixed support that inhibits all movement, including vertical or horizontal displacements as well as any rotations. The other end is unsupported, and therefore it is free to move or rotate.

This free end is often called the tip of the cantilever. Removing the singe support or inserting an internal hinge, would render the cantilever beam into a mechanism: a body the moves without restriction in one or more directions. This is unwanted situation for a load carrying structure.

As a result, the cantilever beam offers no redundancy in terms of supports. If a local failure occurs the whole structure would collapse. These type of structures, that offer no redundancy, are called critical or determinant structures. To the contrary, a structure that features more supports than required to restrict its free movements is called redundant or indeterminate structure.

The cantilever beam is a determinant structure. The static analysis of any load carrying structure involves the estimation of its internal forces and moments, as well as its deflections.

cantilever slab design calculation

Typically, for a plane structure, with in plane loading, the internal actions of interest are the axial force Nthe transverse shear force V and the bending moment M. For a cantilever beam that carries only transverse loads, the axial force is always zero, provided the deflections are small. Therefore it is rather common to neglect axial forces. The last two assumptions satisfy the kinematic requirements for the Euler Bernoulli beam theory that is adopted here too.

For the calculation of the internal forces and moments, at any section cut of the beam, a sign convention is necessary. The following are adopted here:. These rules, though not mandatory, are rather universal. A different set of rules, if followed consistently would also produce the same physical results.

The load w is distributed throughout the cantilever span, having constant magnitude and direction. Its dimensions are force per length. Either the total force W or the distributed force per length w may be given, depending on the circumstances.

Calculation Example – Cantilever Beam

The following table contains the formulas describing the static response of the cantilever beam under a uniform distributed load w. The force is concentrated in a single point, located at the free end of the beam. In practice however, the force may be spread over a small area, although the dimensions of this area should be substantially smaller than the cantilever length.

In the close vicinity of the force application, stress concentrations are expected and as result the response predicted by the classical beam theory is maybe inaccurate. This is only a local phenomenon however. As we move away from the force location, the results become valid, by virtue of the Saint-Venant principle.

The following table contains the formulas describing the static response of the cantilever beam under a concentrated point force Pimposed at the tip. The force is concentrated in a single point, anywhere across the cantilever length.

In practice however, the force may be spread over a small area.To browse Academia. Skip to main content. Log In Sign Up. Download Free PDF.

Cantilever Slab Design. Ramjan Shehzaad. Under the loads, it bends and the directions of its bending depend on its shape and support conditions. A beam bends only in one direction, i. Therefore, slabs may have different names depending upon its bending, support conditions and shapes. For example, a slab may be called a One-way simply supported rectangular slab, b Two-way simply supported or restrained rectangular slab, c Cantilever rectangular slab, d Fixed or simply supported circular slab, etc.

One-way slab means it bends only in one direction and, therefore, reinforcement for bending i. A slab supported on all sides bends in all the directions so the main reinforcements provided shall be such that they may be effective in all directions. For ease of analysis and convenience of reinforcement detailing, the bending moments in a slab are calculated in two principal directions only and, therefore, such a slab is called a two-way slab.

A slab is designed as a beam of unit width in the direction of bending. In this unit, only the most commonly used rectangular slabs, with uniformly distributed load is described. For solid slabs, the values given below : Overall or or Depth of more less Slab mm K 1.

Temperature and shrinkage reinforcement is provided along the direction perpendicular to the span. This is illustrated through the following example. Example 4. Load data and design parameters are given below : Load Data Lime terrace topping of mm thickness is provided over the slab. Figure 4. The detailing of the reinforcement has been shown in Figure 4.

Only temperature and shrinkage reinforcement is provided along the long span. The top of slab is covered with mm lime terrace. Imposed Design a roof slab simply supported on all its four edges of effective spans load may be taken as 1. Substituting all the values in the above equation. Distribution Steel 0. Reinforcement detailing has been shown in Figure 4. The other specifications for design and detailing for the slab are the same as those for simply supported beams Section 3.

Describe the maximum horizontal distance between parallel main bars and that between parallel temperature and shrinkage bars. Being monolithic with the beams, the corners are prevented from lifting and, therefore, torsional reinforcements are provided to resist the resultant torsional moments. Main reinforcements are provided along both the principal axes to resist corresponding moments Mx and My, respectively.

Detailing of reinforcement is done in the following manner : a A slab is divided in edge strips and a middle strip in both directions as shown in Figure 4.A structural engineer posted a picture of a large cantilever slab construction on LinkedIn, and so many reactions have followed the picture due to its size and dimensions.

Cantilever structures are generally structures that are fixed or continuous at one end, and free unsupported at the other end. As a matter of fact, they are one of the most challenging structures to design given that the bending moment increases with the square of the length, while the deflection increases to the fourth power of the length. As a result, controlling deflection and dealing with stability of large span cantilever structural systems is always a challenge in design.

Read Also… Design of large span cantilever structures Structural design of cantilever slabs. We have posted the comments from various professionals on the post to enable us review, scrutinize, and assess the possibility of designing and constructing such type of structure. However the exact span, design data, calculation sheet, and drawings of the structure were not made available, but a lot of people still managed to lend their voices to the construction. He suggested that cables could have been used to support the slab further.

According to him. The slab is too thick whereas the supporting structures are too thin. It looks like to take care of the cantilever load and moments coming on the slab the thickness has been increased. Hopefully the designer has checked all the loads and moments properly otherwise it is going to fail in the long run. The best option would have been to provide some sort of pulling arrangements at the top corner of the slab via cables or pin jointed stereo frames at the outmost corner where there is no support from the bottom of the slab and that way the designer would have succeeded in decreasing the slab thickness as well as given an aesthetic look to it.

E from the USA commented that the loading on the slab may not be high enough to cause serious problems. There are some issues, but if the math and science can be proved it can be done. Usually in situations like this, the loading is majorly under developed so when you compare the loading to the strength, it will be sufficient. But in reality the loading is not high enough. Expect psf live load to psf live load and use a heavy concrete weight with pci strength or pci strength.

They tend to screw up the mix design on these. This is possible. The slab must have been designed as two adjecent edges supported slab. I did come across such a design in early stages of my career as structural engineer. Tech from India also considered the safety of the structure to be doubtful due to the lack of a back span and said. That seems to be a dangerous cantilever.

I hope it must have been designed and checked well. According to him. No back span, seems to be very dangerous. Looks very huge self weight due to higher thickness.Contents [ hide show ]. Looking for more information? Fill in the form and we will contact Professional Publications Inc.

PPI for you. Create a free account and view content that fits your specific interests in structural engineering Learn More. Contents [ hide show ] Description Selected Topics Have questions? Contact Professional Publications Inc. PPI now. This calculation is an example problem in structural engineering. This content is sponsored by PPI. For similar problems, see the list of review books by PPI. See a complete list of review books with similar examples.

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cantilever slab design calculation

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Design of Cantilever Slab Spreadsheet

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Analysis and Design of Slabs “One Way”

Students Click Here. Related Projects. Hello everyone, I am trying to design a 2. My initial observation is that its impossible to design the beam reinforcement. I kept increasing the reinforcement just to observe but it still fails under "Composite Shear-Torsion verification". Currently i have 14fi26 for torsion and 7fi20 for bending which is overkill I also have 10mm stirrups with four bars resisting shear.

Therefore now i am trying to think of ways to reduce the torsion transferred to the beam by the cantilever slab? My first thought is to use wide shallow beams that extend from the end of the interior slab across the two outer columns up to the end of the cantilever slab.

My next thought is to design the beam as an inverse L-shaped beam therefore adding a a bit more of torsional resistance. Again this allows to involve the column more in directly resisting the load from the slab. One more thought is if I am actually modelling this correctly in regards to the torsion transfer from the slab to beam. Quote OP My question is, shall i reduce the torsion transfer to the beam Kellez, I would agree with KootK and transfer your cantilever hogging moment into the back span rather than trying to get the beam to take this in torsion.

Your thk slab for a 2. Hello KootK, first of all thanks a lot for your post that is some great info there, i really appreciate it. Ive done some research and i will do some more later on.

Ok so the main thing here is that i will not design the beam for torsion and only provide the minimum torsional reinf.