Advantages and disadvantages of flat slabs and standard column beam slabs free download as word doc. 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. How to design reinforced concrete flat slabs using finite. Unanswered questions why barbara spear webster given a in memory of on murder she wrote.
Advantages of flatslab reinforced concrete structures are widely known but there are also known the disadvantages concerning their earthquake resistance. 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. Download reinforced concrete designers handbook pdf. An overview and guide to oneway slab systems, written by mohamed basheer bava, lead structural engineer with bsbg. Design of reinforced concrete flat slabs to bs 8110 civil. Posttensioning, which is a form of prestressing, has several advantages over standard reinforcing steel rebars. Volume 4, issue 12, july 2015 63 loads and boundary conditions the slab is carrying a total working load equal to 12. Guidelines for a oneway concrete flooring system brewer. The design principles of a solid slab bridge deck may be illustrated by the following illustrative example. Comparative study of reinforced concrete flat slabs with and. Without a doubt, slab foundations have advantages and disadvantages. The floor system is the major part of a building structure. Flat slab types, uses, advantages and disadvantages daily civil.
From functional aspect a flat slab building is more efficient than a r. Introduction to flat slabs modelling of reinforced concrete. Pdf flatslab building is very popular from the aesthetic and architectural point. What are the advantages and disadvantages between post. The clear advantages of concrete flat slab system made a revolutionary success, years before a rigorous theoretical understanding of their behavior. Waffle slab purpose, uses, advantages and disadvantages. Nancy debora assistant professor civil karunya university 2. Flat slab system is an important division of concrete floor system. 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.
For spans over 9 m posttensioning should be considered. The principal feature of the flat plate floor is a unifo. What are the advantages and disadvantages between post tensioned slab and pre tensioned slab. Flat slab structure is more economical than that of conventional slab structure. As reinforcement detailing of flat slab is simple, it is easier to place. 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. The results indicate that post tensioned flat slabs are cheaper than the rcc slab systems. What are the advantages of one way slab and two way slab. 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. 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. Advantages and disadvantages of flat slabs civil engineering.
Property owners in those parts of the county where it freezes for months on end typically opt for a different kind of foundation. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. This uniqueness manifests itself in a suite of benefits in structural quality, cost savings, safety, and more. So, construction of flat slab building is increasing also in high seismic zone in this paper the response of flat slab building and a. 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. Design considerations for reinforced concrete flat slab floor. 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. We aim to close the gap to the industry by improving the awareness about latest trends in civil engineering. 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. 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. In two way slabs, load will be carried in both the directions. Palmer updated july 17, 2017 hunker may earn compensation through affiliate links in this story. Click on the button below to get the pdf file and read offline.
Jul 18, 2014 the principal features of a flat slab floor are a flat soffit, simple formwork and easy construction. It allows slabs and other structural members to be thinner. Approximately 10% of the vertical member could be saved. A part of slab bounded on each of the four sides by centre line of column is called a panel. The advantages of applying flat slabs are many like depth solution, flat soffit and flexibility in design layout. 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. The selection of an appropriate system is vital in achieving an overall economic building. Flat slab sized for punching shear and deflection additional reinforcement added to span steel to reduce deflections typically 25% extra on a 7. Flatslab construction definition of flatslab construction.
Flat slabs are particularly appropriate for areas where tops of partitions need to be sealed to the slab soffit for acoustic or fire reasons. National conference on recent trends in engineering. It reduces or eliminates shrinkage crackingtherefore no joints, or fewer joints, are needed. 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. Flat slab construction definition is reinforcedconcrete floor construction not requiring beams and girders to transmit the floor load to supporting columns. Two way punching shear concept explained and flat plate example csa a23. Also explore the seminar topics paper on flat slab with abstract or synopsis, documentation on advantages and disadvantages, base paper presentation slides for ieee final year civil engineering ce or ieee civil construction btech, be, mtech students for the year 2015 2016. The execution of the design will be explained with reference to an example. Flat slab is a reinforced concrete slab supported directly by concrete 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.
Because of the brittle nature of shear failures, conservative design is necessary. Nalitolela for the department of civil engineering of mbeya university of science and technology. Post tension slab advantages and disadvantages of post. 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. Flat slab called beamless slab is a slab supported directly by columns without beams. 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. Flat slab analysis, design and detailing pdf civil. 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. Oneway and twoway slabs oneway slabs transfer the imposed loads in one direction only. The flat slab is somewhat more expensive in labor than is the flat plate, but the forms for the column. As no beam is used, floor height can be reduced and consequently the building height will be reduced. 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.
Flat slabs common practice of design and construction is to support the slabs by beams and support the beams by columns. The slab is without drops and is supported internally and on the external long sides by square columns. As reinforcement detailing of flat slabs is simple it is easy to place. Design a solid slab bridge superstructure having a clear span of 9. Also punching shear stress is reduced by adopting drop at slab column connection. The speed of construction for such slab is faster compared to conventional slab. Slabs are constructed to provide flat surfaces, usually horizontal, in building floors, roofs, bridges, and other types of structures. Flat slab structure leads to economic saving, aesthetic view when compared to the conventional slab structure. Oneway and twoway slabs university of asia pacific. As the heroes of flooring, roofing, bridges, and mezzanine systems, there are 7 main advantages of precast hollowcore slabs. 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.
Hence in warehouses, offices and public halls some times beams are avoided and slabs are directly supported by columns. Its not like a flat slab which is here and there i. Even though they can become damaged, theyre very popular, especially in warm climates. 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. Flat slab building is very popular from the aesthetic and architectural point of view.
Analysis and design of flat slab by aci code with matlab coding. Nov 29, 2012 civilax is the knowledge base covering all disciplines in civil engineering. In this research, finite element analyses have been carried out to predict how much seismic loading a flat slab column connection can endure. Review paper on behavior of flat slab under dynamic loading.
Eliminating drops results in simpler falsework and formwork arrangements. Beside this, due to shear problems at column heads, the thickness of flat slab is greater. Flat slabs are capable to carry concentrated loads. 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. Keywords soil structure interaction, stresses distribution, modulus of sub grade reaction ks. 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. This publication seeks to introduce fe methods, explain how concrete can be successfully modelled and how to interpret the results. They may be supported on two opposite sides only fig. Waffle slabs provide stiffer and lighter slabs than an equivalent flat slab. Generally not suitable for supporting brittle masonry partitions. The beams reduce the available net clear ceiling height. In this study fe analysis of flat slabs is proposed.
It uses 30% less concrete and 20% less steel than a raft slab. From figure 9 and 10 it is clear that the quantity and cost of steel and concrete for flat slab structure is 15. Pdf flat slab column connection has received much attention in recent. The name waffle comes from the grid pattern created by the reinforcing ribs. 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. It is one of the most common forms of construction of floors in buildings. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. 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. 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. Finite element fe analysis, is a popular powerful computer method of analysing flat slab concrete structures.
There are a wide range of advantages and benefits for large as well as small projects. Design considerations for reinforced concrete flat slab floor system harshal deshpande1, radhika joshi2. For commercial buildings flat slab rising up to 10 to 20 stories is quite popular. One of our trademarks is the inhouse manufacturing of precast hollowcore slabs. 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. Flat slab analysis and design pdf flat slab design pdf 1 this pdf lecture is created by eng. Numerical analysis of a reinforced concrete slabcolumn. Advantages and benefits of unbonded posttensioning by larry b. The principal features of a flat slab floor are a flat soffit, simple formwork and easy construction. Krauser march 15, 2007 unbonded posttensioning is an efficient structural system that has successfully been used worldwide in construction. 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. In addition to this, the shear capacity can also be reduced in particular around the column head where large shear forces can develop. Flat slab types of flat slab design and its advantages. Projected cost for flat slab without drop slab is 29 % higher than with drop slab.
Flat slab types, uses, advantages and disadvantages. Analysis of flat sanalysis of flat sllab ab punching shear 1. Pdf development of flat slab column interaction with different. Advantages of rib clay pot slab over solid concrete slab. However, flat slabs have a lower stiffness in comparison to a beamcolumn floor plan which can lead to relatively large deflections. Even though building flat slabs can be an expensive affair but gives immense freedom to architects and engineers the luxury of designing. 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. Advantages and disadvantages of flat slabs and standard column. A flat plate floor system is a oneway or twoway system usually supported directly on columns or load bearing walls. Flat slab seminar report, ppt, pdf for civil engineering. Flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams. Flat slab analysis, design and detailing pdf civil engineering. Besides its various advantages, flat slab still has a weak point. C slab built monolithically with the supporting columns and reinforced in two or more directions.
The most important advantages of flat slabs are given below. Design and detailing of flat slab ese soedarsono hs 27 february 2002 content introduction benefits. Advantages of rib clay pot slab over solid concrete slab published on january, 2017 january, 2017 25 likes 2 comments. 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. 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. Pdf analysis of flat slab connection system for seismic loads. In two way slab, the ratio of longer span l to shorter span b is less than 2. Panel may be divided into column strip and middle strip. The benefits of using insitu concrete flat slab construction should be. Pdf the posttensioning method is now a days increasing widely, due to its application. A civil engineer must know all the aspects regarding the flat floor system. Beside this, due to shear problems at column heads, the thickness of flat slab. Comparative study of post tensioned and rcc flat slab in. Fast and easy construction disadvantages of flat slab system concrete slabs are one of the most.
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