Pdf effect of flat slab to progressive collapse on. Here, we have tried to gather various reading materials available in the web about flat slab floor system in one place. Hence the flat slabs 3 l2a l2b c of panel a c of panel b middle. Flat slabs are twoway slabs supported by pointlike supports. The grid is formed by the removal of molds after the concrete sets. Shear reinforcement is not required at the columns. However, the equivalent frame method is commonly used for the analysis of the flat slab structures subjected to lateral loads in practical engineering. I ultimately decided to break apart the spans and do a frame due to the large thickness of concrete required. Flat slab is defined as one sided or twosided support system with sheer load of the.
This research aimed to analyse the influence of flat slab against progressive collapse at irregular building structures, and determine the type of collapse that occurred at irregular building. Flatplate and flatslab roofs concrete construction magazine. Beams are not used therefore under floor services outside the drops are simple. Hence the flat slabs 3 l2a l2b c of panel a c of panel b middle stripmiddle. This flexibility results from the use of a square or nearsquare grid and the absence of beams, downstands or drops that complicate the routing of services and location of partitions. Bookmark file pdf bubble deck voided flat slab solution bubble deck voided flat slab solution bubbledeck biaxial hollow precast slab system the bubbledeck system virtually eliminates dead weight concrete from the middle of a floor slab by incorporating recycled plastic. The materials to be used are grade c25 concrete and grade 500 reinforcement. Also, speedy turnaround can be achieved using an arrangement using early striking and flying systems. The flat slab is a twoway reinforced structural system that includes either drop panels or column capitals at columns to resist heavier loads and thus permit longer spans.
Seismic analysis of flat slab building with shear wall ijert. Slab thickness having chosen a flat slab solution, the next key issue is to determine an appropriate slab thickness. Apr 18, 2018 flat slab is used when column and beam in the structure is undesirable like in cinema hall when you look around there will be no beams or column. Pdf comparison study for various structural slab systems. Flat plate system a flat plate floor system is a twoway concrete slab supported directly on columns with reinforcement in two orthogonal directions figure 1a. While designing structure layout and during implementation using sub frame. A flat slab can also become a major source of energy inefficiency, as structures tend to lose heat through the concrete. This method is used even today for the design of flat slabs and flat plates and is known as the direct design method. Punching of flat slabs design for shear at the column heads. Depth study flat plate concrete slab overview initial investigation of options for structural systems for this type of building revealed that the existing steel structure is typically the ideal selection. Flat slab with big shear wall in conventional diagonal abdul karim mulla 2015. Flat slab types, uses, advantages and disadvantages. Causal mechanisms and consequences of flat slab subduction causal mechanisms.
Design of reinforced concrete structures ii twoway slabs. Flat slab construction can deeply reduce floorto floor. Flat slabs are economically viable for spans range from 6 to 9m and live loads range from 4 to 7 knm 2. These systems rely on shear walls to sustain lateral load effects, whereas the slabcolumn structure resists mainly gravity loads. 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 civil engineering. Because of the threedimensional structure and the gentle graduated force flow, the hollow spheres will have no negative influence and cause no loss of strength. Flat slabs are similar to flat plate apart from thickening of flat slabs around columns which are provided to improve shear capacity of this floor system.
Jul 28, 2014 the flat plate is a twoway reinforced concrete framing system utilizing a slab of uniform thickness, the simplest of structural shapes. Design considerations for reinforced concrete flat slab floor. A civil engineer must know all the aspects regarding the flat floor system. It is one of the most common forms of construction of floors in buildings. A six storey building for a commercial complex has plan dimensions as shown in figure 1. Flat slab is used when column and beam in the structure is undesirable like in cinema hall when you look around there will be no beams or column. Bending will take place in the two directions in a dishlike form. In the equivalent frame method, the flat slab system is modeled as an equivalent frame and an elastic analysis is performed. Flat plate concrete floor system does not use beams between. 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 thickness of slab over columns is also increased to support heavy loads and the thickened part of the slab is called drop panel. 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. Twoway flat plate concrete floor system analysis and design. The column tends to punch through the slab in flat slabs, which can be treated by three methods. The benefits of using flat slab construction are becoming increasingly recognised.
The 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. Review paper on behavior of flat slab under dynamic loading. Cven 444 structural concrete design structural system overview dr. 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. The flat plate is a twoway reinforced concrete framing system utilizing a slab of uniform thickness, the simplest of structural shapes.
Given the height, spans, and use of the structure, composite steel beam. These shear walls transfer the lateral loads to the foundation by their shearing resistance and resistance to overturning. The effectiveness of its structural system to withstand. Advantages and disadvantages of flat slabs and standard. Jul 18, 2014 a flat slab is a oneway or twoway system with thickenings in the slab at the columns and load bearing walls called drop panels figure 9. A flat slab can also become a major source of energy inefficiency. Flat slabs are used by engineers in many building due to its advantages over other reinforced concrete floor system in different cases. In the present work, summarized the importance of flat slab construction and revealed the relevance of shear wall in a flat slab multistoried building. Recently had a 4column concrete structure and contemplated a flat slab.
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. Flat slab analysis, design and detailing pdf civil engineering. Sandt summer 2003 semester slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Charleson, seismic design for architects, architectural press 2008, p. The floor system of a library consists of a 6in thick reinforced concrete slab resting on four floor steel beams, which in turn are supported by two steel girders. Design considerations for reinforced concrete flat slab floor system. Shear strength of beamless slabs usually a controlling factor. A civil engineer should study these lectures and materials for structural engineering acumen. There are several working hypotheses for the initiation of flat slab subduction. Flat plate concrete floor system does not use beams between columns or. Department of mechanics, materials and structures english courses reinforced concrete structures code.
Seismic analysis of flat slab building with shear wall written by athira. Where proprietary systems are used the control perimeter at which. Flat slab structure is more economical than that of conventional slab structure. When the height of the building increases, the building should have a good lateral load resisting capacity. A waffle slab is flat on top, while joists create a grid like surface on the bottom. Using a drop panel and a column capital in flat slab. Flat slab design structural analysis beam structure. A flat plate is a one or twoway system usually supported directly on columns or load bearing walls. In present work, a flat slab system is a significant advancement. Finally, an example of a flat slab floor system is presented to illustrate the practice. Design considerations for reinforced concrete flat slab. The minimum thickness can be determined by many factors.
Reinforced concrete flat plate system, eugene, usa s. Flat slab sized for punching shear and deflection additional reinforcement added to span steel to reduce deflections typically 25% extra on a 7. Design of reinforced concrete structures ii twoway slabs 1 1. Chapter 18 concrete slab structures january 2019 183 18. By knowledge we know that flat slab is preferred as a floor system because of its architectural appearance, flexibility of flat slab rc structure, easy to construct and economic structure. There are many methods to incorporate lateral load resisting ability into a structure.
Usually during design the middle strip or middle of the slab, critical deflection exists while designing the layout of the structure one must be sure about the anticipated deflection to be as accurate as possible. The flat plate expansion device standard microstation drawings are combined into six drawing files. Because of the absence of deep beams and shear walls, flatslab structural system is significantly more flexible for lateral loads then traditional rc frame system. A simplified drawing of a flat slab plate or waffle slab structure adapted from. Flat slab is a reinforced concrete slab supported directly by concrete columns without the use of beams.
Types of economical floor systems for reinforced concrete. Beside this, due to shear problems at column heads, the thickness of flat slab is greater. The slab is outside buildings which subjected to 1 hr fire resistance and design for 50 years design life. Primarily used in hotels, multifamily residential buildings, and hospitals, this system has the advantages of simple con. Abhishek lakshman dhangar, a comparative study of flat slab structure and conventional structure. Efficient analysis of flat slab structures subjected to.
Design considerations for reinforced concrete flat slab floor system harshal deshpande1, radhika joshi2. Pdf irregular flat slabs designed according to the structural. Pdf in a developing country like india the benefits of posttensioning system are yet to be recognized. The buoyant ridge hypothesis seems to be favored at the moment. Department of mechanics, materials and structures english. Is 4562000 recommends the analysis of flat slab and column structure as a. Flat slab analysis, design and detailing pdf civil. Flat slab types of flat slab design and its advantages. The main hotel flatslab emulation could be constructed using four precast concrete components. As manual calculation method the method of substitutive frames or.
Bubbledeck behaves like a spatial structure as the only known hollow concrete floor structure. Flat slab flat slabs thin structure flat soffits no beams 80% of concrete framed buildings are flat slabs 4 million m2 built each year in uk. You can consider it as beam with breadth more than 1m directly resting on column. Flat slab haunched slab a longitudinal slab is one of the least complex types of bridge superstructures.
This structure was designed to be more solid when used on longer spans and with heavier loads. It is a square floor system, the edge beams support the same triangular load the area of the slab portion that is supported by a particular beam is called the tributary area. Pdf analysis of flat slab structures with outriggers. Advantages and disadvantages of flat slabs and standard column beam slabs free download as word doc. Seismic analysis of flat slab by using etabs international journal. What is the maximum length of the span for a flat slab. A flat slab is a oneway or twoway system with thickenings in the slab at the columns and load bearing walls called drop panels figure 9. If a flat plate or flat slab is otherwise suitable for a particular structure, it will be found that there is the additional benefit of minimizing the story height.
Mar 17, 2020 it can settle on uneven ground, allowing the structure to settle as well, for example, and during seismic activity, a slab foundation cannot hold up if the soils are subject to liquefaction. The thickness of a floor slab must be determined early in design because the weight of the slab is an important part of the dead load of the structure. Liftslab system with walls prestressed slabcolumn system liftslab systems were introduced in the last decade of. Flat slabs system of construction is one in which the beams used in t he conventional methods. Crosssectional areas of the floor beams and girders are 14. Pdf in the construction industry, the need for flat slabs supported on columns in an irregular.
The best flat slab analysis, design and detailing related pdf and slides are. Windows can be extended up to the underside of the slab. 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 1 knm2, and unfactored live load 1. Pdf the structural performance of a common type of office buildings was examined. Flat slab system is an important division of concrete floor system. For lighter loads the column heads and drop panels are eliminated, such flat slab with constant thickness supported on prismatic columns are called flat plate. The building is located in seismic zone iii on a site with medium soil. It can settle on uneven ground, allowing the structure to settle as well, for example, and during seismic activity, a slab foundation cannot hold up if the soils are subject to liquefaction.
By definition, a flat slab structure consists of a slab built mono. Common practice of design and construction is to support the slabs by beams and. Flat slab subduction is an active area of research. Blast design procedure for flat slab structures dtic. Although there are multidimensional advantages of flat slab system but there are certain areas in which one must be watchful and cautious. Flat slab with big shear wall in conventional outrigger sizes, location of outriggers, thickness of outriggers etc. Reinforced concrete design 1 design of slab examples. Design and construction of reinforced concrete flat slabs.
The main objective of this report is to present different structural flooring that are intended to be considered by the structural designers in the design efforts during the different coming design development stages for the project of thakher city. Determine the floor loads on the floor beams, girders. Flat slab structure leads to economic saving, aesthetic view and yet allow the architect from great freedom of form works as compared to conventional slab structure. In areas of absolute height restrictions, this may enable one to have an additional floor for approximately each 10 floors, as compared. The slab has to carry a distributed permanent action of 1. Nancy debora assistant professor civil karunya university 2. Diagram showing examples of flat plate and flat slabs. I figured you would need atleast 2 edge beams in the long span, and if you are forming 2 beams, might as well form 5 for a stiffer structure. Pdf flat slabs are highly versatile elements widely used in construction. The concrete floor slab system shown below is for an intermediate floor to be designed considering partition weight 1 knm2, and unfactored live load 1. Flat slab is a reinforced concrete slab supported directly by concrete columns without use beams.
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