What are the advantages of one way slab and two way slab. Punching shear resistance of flat slabs with opening dr samal m. Flat slabs are particularly appropriate for areas where tops of partitions need to be sealed to the slab soffit for acoustic or fire reasons. What are the advantages and disadvantages between post tensioned slab and pre tensioned slab. 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. Keywords soil structure interaction, stresses distribution, modulus of sub grade reaction ks. Flat slab types, uses, advantages and disadvantages. Pdf the posttensioning method is now a days increasing widely, due to its application. As per the cost comparison for flat slab panel 6mx6m for with drop and without drop, the results show that from economic point of view slab with drop provision is preferable. Design of reinforced concrete flat slabs to bs 8110 civil. A detailed explanation will be given of the checksto be carried out, the aspects to be considered in the design and the construction procedures and sequences of a posttensioned slab. Property owners in those parts of the county where it freezes for months on end typically opt for a different kind of foundation. Fast and easy construction disadvantages of flat slab system concrete slabs are one of the most. Advantages and disadvantages of flat slabs and standard column.
Guidelines for a oneway concrete flooring system brewer. Advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. Flat slab types of flat slab design and its advantages flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams. Pdf flatslab building is very popular from the aesthetic and architectural point. It allows slabs and other structural members to be thinner. Krauser march 15, 2007 unbonded posttensioning is an efficient structural system that has successfully been used worldwide in construction. As no beam is used, floor height can be reduced and consequently the building height will be reduced. Flat slab seminar report, ppt, pdf for civil engineering. This uniqueness manifests itself in a suite of benefits in structural quality, cost savings, safety, and more. As reinforcement detailing of flat slab is simple, it is easier to place. We aim to close the gap to the industry by improving the awareness about latest trends in civil engineering. Comparative study of reinforced concrete flat slabs with and. Design and detailing of flat slab ese soedarsono hs 27 february 2002 content introduction benefits.
Flat slab system is an important division of concrete floor system. It is one of the most common forms of construction of floors in buildings. Because of the brittle nature of shear failures, conservative design is necessary. Download reinforced concrete designers handbook pdf. The benefits associated with flat slab construction may well outweigh those of other structural solutions, which could be more complicated, timeconsuming and ultimately more costly. Finite element fe analysis, is a popular powerful computer method of analysing flat slab concrete structures. Rashied faculty of engineering, university of sulaimani kurdistan of iraq abstract there are numbers of methods have been proposed to evaluate the influence from opening on punching shear resistance in flat slabs in the vicinity of columns. Analysis of posttensioned flat slab by using safe shriraj s.
Flat slab sized for punching shear and deflection additional reinforcement added to span steel to reduce deflections typically 25% extra on a 7. Flat slab analysis and design pdf flat slab design pdf 1 this pdf lecture is created by eng. Eliminating drops results in simpler falsework and formwork arrangements. How to design reinforced concrete flat slabs using finite. Design considerations for reinforced concrete flat slab floor. Also punching shear stress is reduced by adopting drop at slab column connection. The beams reduce the available net clear ceiling height. Flat slab building is very popular from the aesthetic and architectural point of view. Approximately 10% of the vertical member could be saved.
Flat slab structure is more economical than that of conventional slab structure. Flat slab called beamless slab is a slab supported directly by columns without beams. For spans from 5 to 9 m, thin flat slabs are the preferred solution for the construction of insitu concrete frame buildings where a square or nearsquare grid is used. Pdf analysis of flat slab connection system for seismic loads. Advantages and disadvantages of flat slabs civil engineering. The clear advantages of concrete flat slab system made a revolutionary success, years before a rigorous theoretical understanding of their behavior. Flat slabs common practice of design and construction is to support the slabs by beams and support the beams by columns. Flat slabs are considered to be faster and more economic than other forms of construction, as partition heads do not need to be cut around downstand beams or ribs.
What are the advantages and disadvantages between post. Slabs and flat slabs lecture 5 19 th october 2016 contents lecture 5 designing for shear in slabs including punching shear detailing solid slabs flat slab design includes flexure worked example exercise punching shear. The floor system is the major part of a building structure. Flat slab is defined as one sided or twosided support system with sheer load of the slab being concentrated on the supporting columns and a square slab called drop panels. This load covers the slab own weight and a live load equal to 3. Analysis of flat sanalysis of flat sllabab moment division example 6000 6000 6000 6000 6000 5000 layout of building 7000 5000 a floor slab in a building where stability is provided by shear walls in one direction ns. Jul 18, 2014 the principal features of a flat slab floor are a flat soffit, simple formwork and easy construction. Two way punching shear concept explained and flat plate example csa a23. However, in terms of labor in building the floor, the flat plate is much cheaper because of the very simple formwork and less complex arrangement of steel. Advantages of rib clay pot slab over solid concrete slab. Slabs are constructed to provide flat surfaces, usually horizontal, in building floors, roofs, bridges, and other types of structures. 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.
An overview and guide to oneway slab systems, written by mohamed basheer bava, lead structural engineer with bsbg. A flat plate floor system is a oneway or twoway system usually supported directly on columns or load bearing walls. Moreover, the design and construction details of this parking garage are used to illustrate code requirements, flat slab analysis, design details, and the construction of gfrprc flat slabs. Waffle slabs provide stiffer and lighter slabs than an equivalent flat slab. It uses 30% less concrete and 20% less steel than a raft slab. Both the systems are analyzed using rapt and etabs respectively which is based on the design methodology. Explore flat slab with free download of seminar report and ppt in pdf and doc format.
Unanswered questions why barbara spear webster given a in memory of on murder she wrote. The principal features of a flat slab floor are a flat soffit, simple formwork and easy construction. Design a solid slab bridge superstructure having a clear span of 9. Nov 29, 2012 civilax is the knowledge base covering all disciplines in civil engineering. Without a doubt, slab foundations have advantages and disadvantages.
For this, the concrete slab is tensioned with a process called prestressing and the slab of concrete which comes out after this process is known. Flat slab construction definition is reinforcedconcrete floor construction not requiring beams and girders to transmit the floor load to supporting columns. Review paper on behavior of flat slab under dynamic loading. Numerical analysis of a reinforced concrete slabcolumn.
Volume 4, issue 12, july 2015 analysis of rc flat slab system. The benefits of using insitu concrete flat slab construction should be. So, construction of flat slab building is increasing also in high seismic zone in this paper the response of flat slab building and a. Oneway and twoway slabs university of asia pacific. A civil engineer must know all the aspects regarding the flat floor system. In two way slab, the ratio of longer span l to shorter span b is less than 2. From functional aspect a flat slab building is more efficient than a r. The economical span l of a reinforced concrete flat slab is approximately d x 28 for simply supported, d x 32 for an end span and d x 36 for an interior span. Panel may be divided into column strip and middle strip. Even though they can become damaged, theyre very popular, especially in warm climates. In two way slabs, load will be carried in both the directions. Nalitolela for the department of civil engineering of mbeya university of science and technology.
Projected cost for flat slab without drop slab is 29 % higher than with drop slab. Department of mechanics, materials and structures english. A part of slab bounded on each of the four sides by centre line of column is called a panel. Even though building flat slabs can be an expensive affair but gives immense freedom to architects and engineers the luxury of designing. The slab may be supported by walls, by reinforced concrete beams usually cast monolithically with the slab, by structural steel beams, by columns, or by the ground slabs are classified into two types. A flat slab is a twoway reinforced concrete slab that usually does not have beams and girders, and the loads are transferred directly to the supporting concrete. Advantages of flatslab reinforced concrete structures are widely known but there are also known the disadvantages concerning their earthquake resistance. Posttensioning, which is a form of prestressing, has several advantages over standard reinforcing steel rebars. In this study fe analysis of flat slabs is proposed. As reinforcement detailing of flat slabs is simple it is easy to place.
From figure 9 and 10 it is clear that the quantity and cost of steel and concrete for flat slab structure is 15. Besides its various advantages, flat slab still has a weak point. Analysis of flat sanalysis of flat sllab ab punching shear 1. Its not like a flat slab which is here and there i. Palmer updated july 17, 2017 hunker may earn compensation through affiliate links in this story. Beside this, due to shear problems at column heads, the thickness of flat slab is greater. Beside this, due to shear problems at column heads, the thickness of flat slab.
Generally not suitable for supporting brittle masonry partitions. The name waffle comes from the grid pattern created by the reinforcing ribs. C slab built monolithically with the supporting columns and reinforced in two or more directions. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. The execution of the design will be explained with reference to an example. Post tension slab although concrete is a strong material for construction, it is not resistant to breakdown especially where longer concrete slabs are required like in a bridge or a length of a beam.
However, there are some pitfalls to avoid, that often catch out the unwary. Flat slab flat slab are also known as beamless slab, is a type of slab in which the flooring slab is directly supported on columns without the agency of beam or girders. The flat slab or post tensioned slab buildings in which slab is directly rested on columns, have been adopted in many buildings constructed recently due to the advantage of reduced floor to floor heights to meet the economical and architectural demands. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only. Salunke mgms college of engineering and technology, kamothe, india mgms college of engineering and technology, kamothe, india abstract the use of posttensioned flat slab is increasing day by day, due to its advantages over traditional concrete. Sachpazis date 18012014 chkd by date appd by 4 internal column c3 consider the reinforcement concentrated in half width strip over the support depth of reinforcement. Flat slab analysis, design and detailing pdf civil. A flat slab is a twoway reinforced concrete slab that usually does not have beams and girders, and the loads are transferred directly to the supporting concrete columns. Design of flat slab with edge beams by direct design method 16 14 14 3 b c 1 c 2 c 3 c 4 3 1 c 5 c. In this research, finite element analyses have been carried out to predict how much seismic loading a flat slab column connection can endure. The results indicate that post tensioned flat slabs are cheaper than the rcc slab systems. The main objective of the paper is to study method of analysis and design of flat slab by using aci 318 08 design codes, with matlab programming for the easy application language for the design of flat slab. The flat slab is somewhat more expensive in labor than is the flat plate, but the forms for the column. Click on the button below to get the pdf file and read offline.
As the heroes of flooring, roofing, bridges, and mezzanine systems, there are 7 main advantages of precast hollowcore slabs. One of our trademarks is the inhouse manufacturing of precast hollowcore slabs. Design considerations for reinforced concrete flat slab floor system harshal deshpande1, radhika joshi2. Pdf development of flat slab column interaction with different. Flat slab structure leads to economic saving, aesthetic view when compared to the conventional slab structure. The advantages of applying flat slabs are many like depth solution, flat soffit and flexibility in design layout. Volume 4, issue 12, july 2015 63 loads and boundary conditions the slab is carrying a total working load equal to 12. Introduction to flat slabs modelling of reinforced concrete. However, flat slabs have a lower stiffness in comparison to a beamcolumn floor plan which can lead to relatively large deflections.
Hence in warehouses, offices and public halls some times beams are avoided and slabs are directly supported by columns. Flat slab types of flat slab design and its advantages. Flat slab types, uses, advantages and disadvantages daily civil. The slab is without drops and is supported internally and on the external long sides by square columns.
The benefits of choosing flat slabs include a minimum depth solution, speed of construction, flexibility in the plan layout both in terms of the shape and column layout. Advantages and benefits of unbonded posttensioning by larry b. Analysis and design of flat slab by aci code with matlab coding. For commercial buildings flat slab rising up to 10 to 20 stories is quite popular.
For spans over 9 m posttensioning should be considered. Waffle slab purpose, uses, advantages and disadvantages. Comparative study of post tensioned and rcc flat slab in. Flat slab is a reinforced concrete slab supported directly by concrete columns. There are a wide range of advantages and benefits for large as well as small projects. The principal feature of the flat plate floor is a unifo. Flat slab analysis, design and detailing pdf civil engineering. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. The flat slab is thickened closed to supporting columns to provide adequate strength in shear and to reduce the amount of negative reinforcement in in 1914 eddy and turner were first wrote on flat slabs, the flat slabs directly rests on columns and walls over other forms of construction and advantages are better.
Nancy debora assistant professor civil karunya university 2. Flat slabs are capable to carry concentrated loads. Advantages and disadvantages of flat slabs and standard column beam slabs free download as word doc. Flatslab construction definition of flatslab construction. They may be supported on two opposite sides only fig. Post tension slab advantages and disadvantages of post. This publication seeks to introduce fe methods, explain how concrete can be successfully modelled and how to interpret the results. The design principles of a solid slab bridge deck may be illustrated by the following illustrative example. Flat slab structures show significant vulnerability under lateral and vertical seismic loading as punching shear failure may occur in the joints of slab and column. 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. In addition to this, the shear capacity can also be reduced in particular around the column head where large shear forces can develop. National conference on recent trends in engineering.
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