floor system in multistory building

8/3/2019 Floor System in Multistory Building

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FLOOR SYSTEM INMULTISTORY BUILDING

Floor Structural Subsystem

Floor Finish Subsystem

Ceiling (Soffit of floor) finish subsystem.


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FLOOR STRUCTURAL SUB SYSTEM

Vertical Loading Function

The main function of the floor structural system is to carry

the live loads and dead loads that are placed on it. Thenthe floor structure has to transfer these loads to eithersupport beams of the structural frame or supportingstructural walls. The floor structure must be stiff enoughas to neither noticeable deflect due to the load nor felt tooscillate when repetitive impact loads (e.g people

walking) are applied.


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Horizontal Loading Function

Act as internal strut of the buildings horizontal loadingstructural system.

Deeper solid floor slabs or joists or girders give betterstiffness to the building

Yet to compensate for the deeper floor slab or girders orjoist, designers will increase the floor-to-ceiling height.

The impact is more expense due to longer ducts, liftshafts, increased materials etc.

On the other hand, if the designer does not increase thefloor to ceiling height, the headroom will be limited andthe use of false ceilings and floors to house the servicesruns is restricted.


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TYPES OF FLOOR

SteelFloorConcreteFloor

Composite steel-concrete


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ADVANTAGES OF COMPOSITE STEEL-

CONCRETE CONSTRUCTION

1. Combination of the advantages of steel withadvantages of concrete

2. Reduced temporary works

3. Reduced wet construction operations

4. Improved usable floor height

space


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Light-weight or normal concrete floorstructures

ONE WAY SYSTEM

TWO WAY SYSTEM


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1. Cast in situ solid Slab

2. Slab on Joist Floors

3. Pre-cast concrete slab

4. Post-tensioned joist supporting precast concrete slab or in situ

concrete slabs.

ONE WAY SYSTEM


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Two way slabs on stiff beams

Two way slabs on shallow joist

bands Flat slabs

Waffle slabs

Pre-cast slabs Diagrid floors

TWO WAY SYSTEM


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Steel Floor Structures

Two classes of steel floor structures

NON COMPOSITE FLOORINTERACTION

COMPOSITE FLOORINTERACTION


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The floor r.c slab can act separately from steelframework. In other words, the steel and concretecomponents of the floor act as separate structural

entities.

NON COMPOSITE FLOOR

INTERACTION


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The floor slab can act in composite way withsteel framework. In other words, the steel and

concrete are keyed to each other and interact as asingle element instead of two separate

components

COMPOSITE FLOOR

INTERACTION


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STEEL FLOOR CONSISTS OF 2COMPONENTS

FLOOR SLAB

HORIZONTAL SPANMEMBERS


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SKIN SYSTEM

CAST IN SITU

CONCRETE

SLAB

CAST IN SITU CONCRETE

SLAB ON CORRUGATED

METAL DECK WITH ANCHOR

STUD

CAST IN SITU

CONCRETE SLAB

ON CORRUGATED

METAL DECK

PRE CAST

CONCRETE

SLAB

CERAMIC

SLAB


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HORIZONTALSPAN MEMBERS

OPEN

WEBBEB

STEEL JOIST

CASTELLATED HOT

ROLLED BEAM

TRUST GIRDERS

LATTICE

GIRDERS

HOT ROLLED

BEAM

VIERENDEEL

GIRDERS

STUB

GIRDERS

TAPPERED OR

HAUNCHED

GIRDERS


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NON COMPOSITE STEEL FLOOR


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COMPOSITE STEEL FLOOR WHERE

STEEL I BEAM IS EMBEDDED IN

CONCRETE


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COMPOSITE STEEL FLOOR USING

METAL DECKING


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TYPES OF COMPOSITE STEEL

FLOORS


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Fire Protection

Contact fire proofing

The steel frame may be fireproofed by eitherencased in a fireproof material such as

concrete or sprayed with contact fire proofingmaterials e.g vermiculite If steel decking is partof the floor system, the soffit of the decking isspayed with contact fire proofing materials e.g

vermiculite


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Ceiling as membrane fire fighting

The ceiling behaves as a fire resistance barrier.

It protects the floor structure and theM&E ducts, pipes and cabling within the ceiling

space fr. the floor below. To prevent fire spreadthrough the ceiling space, fire curtains are

installed in the ceiling space to fire-compartmentalise the space


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Accommodation of Services

1. Below the floorThe horizontal M&E pipes and ducts are suspendedeither from the floor frame or from the soffit in thesuspended ceiling space.

2. Within the floorThe M&E pipes and ducts are directly supported bythe floor either through the penetrations in the floorcomponents e.g. holes through beams, trussesgirders or imbedded in the concrete slab or in chasesin the floor slab.

3. Above the floorThe M&E pipes and ducts are directly supported onthe floor in the space created by raised floors.


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FLOOR FINISH SUBSYSTEMS

Screed floorThe floor finish is usually screed which is laid on theconcrete slab. Tiling or membrane type covers (e.g.carpet, linoleum) are laid on the screed. Access boxesfor the M&E ducts lain in the floor slab are positioned

relevant to the layout of the floor.

Raised floorPropriety raised floor systems are installed onto the floorcreating a false floor. Space within the raised flooraccommodate M&E ducts, cables etc and allows theused of under-floor air-conditioning plenums.Manufacturing have devised raised floor systems thatmodular and integrated for accomodating airconditioning, electricity and telecommunication serviceslines.


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Ceiling Subsystems

Wet construction

- Plaster or spray finish orcemented acoustic tilingthat are clad directly to

the floor soffit.

- May also be in the form orwet plastering on dryboards on a frame that iseither suspended from thefloor soffit or fixed

directly to the floor soffit

- Usually for residentialbuilding

Dry construction

- Dry boards or tilesfastened on a frameeither suspended from the

floor soffit or fixeddirectly to the floor soffit.

- Made from gypsum, metallath, wood cement etc.Tiles are usually of theacoustic type.

- Ceiling are either attacheddirectly to the floor orsuspended with hangingwires or rods from thefloor.


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Suspended ceilings

SOLID TYPE

GRID TILETYPE

LINEARPLANKING

TYPE


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CONSTRUCTION OF SUSPENDED

CEILING

Assembly of separate parts installed by varioustradesmen. The parts are standard design componentsand may be sourced from different manufacturers.However the dimensions of the light, air-conditioning andfire safety fittings are usually aesthetically incompatible

with the ceiling Assembly of a complete propriety system from a single

manufacturer. Such a ceiling is called an integratedceiling. An integrated ceiling is either of the linear planktype or the grid tile type. The ceiling system consists ofthe following components.

- ceiling support system- ceiling materials for acoustic and fire protection

- light fittings

- HVAC air diffuser

floor system in multistory building

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