Steel Strucuture

8/13/2019 Steel Strucuture

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QSD 282CONSTRUCTION TECHNOLOGY

MOHD HELMI BIN MOHD NASIR 2007105023

SYAFIQ ALIF BIN SOKARNO 2007203982

MOHD NAZMI BIN SAADON 2007104929MOHD TARIQ BIN ABD RASHID 2007105161

Prepared By:

STEEL STRUCTURE

Prepared For: PN SITI SARAH BINTI MAT ISA

QS4D


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INTRODUCTION

Steel structure can be divided in twotypes hot rolled and cold rolled.


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Cold Rolled Steel

The cold-formed steel shapes are formed at roomtemperature.

Cold-formed steel structural members are shapescommonly manufactured from steel plate, sheet metal orstrip material.

The manufacturing process involves forming the material byeither press-braking or cold roll forming to achieve thedesired shape.

There are particularly useful in lightweight situation wherestandard hot rolled would be excessive. Development of zedand sigma section has proved very successful alternativesto the traditional use of steel angle for truss purlins.

Example of Cold-Formed Steel that would not be consideredframing includes metal roofing, roof and floor deck,composite deck, metal siding, and purlins and girts onmetal buildings.


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Hot Rolled Steel

The hot rolled steel shapes are formed at elevatedtemperatures. It is the most used structuralsteelwork.

Universal beam and column are produced in a range

of standard size the inside dimension and weightdesigned by serial sizes.

Each serial has inside dimension between flange andflange edge and web remain constant. The deep webto flange dimension of beam are chosen as structuralelement. Standard hot rolled are given in BS4 and BSEN 100067


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ADVANTAGES OF STEEL

STRUCTURE

Recycling

The material is 100% recyclable. The steel industryannually saves enough energy to power 18 millionhouseholds for a year.

Strength and durability

Steel framing material is significantly stronger thanwood. No other construction material can matchsteel's superior strength and durability. Steel has thehighest strength-to-weight ratio of any constructionmaterial. Steel's strength and non-combustiblequalities enable a steel framed structure to betterresist such devastating events as fires, earthquakes,and hurricanes.


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ADVANTAGES OF STEEL

STRUCTURE (Contd)

Termites

Steel is simply impervious to termites and other dam age-causing bugs and pests.

Weight

Steel components weigh 60% less than wood. Steel is light butvery strong. Foundations can be lighter; transportation andsite handling are easier.

High structural efficiency

Steel components allow for longer spans with less postsupports. Steel has one of the highest weights to strengthratios of all construction materials. This strength advantagemeans better design flexibility, wider spans and better materialusage.


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DISADVANTAGES OF STEEL

STRUCTURE

Availability of labour and tools In many areas it is difficult to find framing crews that are

trained in light steel construction. In addition to the labourtraining required to convert to the use of steel, builders andlabourers must obtain some new tools not presently used bycarpenters. The combination of additional training and tools

translate to increased costs of construction for a short periodof time.

Thermal conductivity Steel is an excellent thermal conductor requiring additional

exterior insulation or thermal breaks to overcome thisdisadvantage.

Rust

Steel components can rust if left exposed in marine climates.


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FACTORS TO BE CONSIDERED

The main factors to be considered inchoosing steel structure are:

Strength and stability

Durability and freedom frommaintenance

Fire safety

Site cost Construction cost


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GIRDERS

Lattice Girder

Where there is a requirement for a large floor area,unobstructed by column a deep lattice girder orvierendeel girder are used.

A lattice girder is a girder where the flanges areconnected by a lattice.

Lattice girders are made by a combination ofstructural sections connected with diagonal bracing.

The girder is fabricated from mild steel plate angle,

channel and beam Section which a cut and welded together to form an

open web beam.


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GIRDERS (Contd)

Trussed Frame Used mainly for short and medium-span

single storey building intended for industrialand recreational use.

The compression members are calledrafters & struts & tension members knownas ties.

Structural members are connected

together, where the centre lines coveragewith flat-shape plates called gussets. Can be riveted, bolted or welded together

to form a rigid triangulated truss.


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GIRDERS (Contd)

Vierendeel Girder The Vierendeel girder members are not

triangulated but form rectangular openingand is a frame with fixed joints that are

capable of transferring and resisting bendingmember.

No diagonal bracing in Vierendeel girder. Thecreation of rectangular openings for doorsand windows is simplified by using this

girder.


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STEEL ROOF TRUSSES

The function for any roof is to provide aprotective covering to the upper surface of thestructure.

A steel roof truss is a plane frame consisting of

a series of rigid triangles composed ofcompression and tension members. Thecompression members are called rafters andstruts, and the tension members are termedties.


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STEEL ROOF TRUSSES (Contd)

Lattice Girder Roof (Sawtooth)

This roof consists of a series of

trusses fixed to girders.Monitor Roof Light

This is a flat roof with raised portionscalled monitors used to admit light.This type of roofing gives a moreuniform level of daylighting.


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FASTENING METHOD

The primary connection method forstructural steel are bolting and welding.

A structures strength depends on proper

use of this connection method. Connections made in a fabrication shop

are called shop connection.

Connections made in the field by the steel

erecter are called site or field connection. Bolting and welding may be used for shop

and site connection.


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FASTENING METHOD (Contd)

Structural Bolting

During hoisting, connecters will install a minimum of 2bolts per connection.

The rest of the bolt are installed and tightened after

the structure is plumed. A systematic pattern must be followed when

tightening bolts so that a joint is drawn together andall fasteners is properly installed.

Thread length is the threaded portion of the bolt.

Bolt length is the distance from behind the bolt headto the end of the bolt.

Grip is the distance from the behind of the bolt headto the back of the nut or washer.


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PARTS OF BOLTS ASSEMBLY

Thread length is the threaded portionof the bolt.

Bolt length is the distance frombehind the bolt head to the end of thebolt

Grip is the distance from behind thebolt head to the back of the nut orwasher.


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Structural Welding

Where there is favourable working conditions, weldingare the most economical way to make strongconnections. Therefore, workshop connections are

usually welded. Welding can be performs in the shopor on site.

Welding is the process of fusing multiple pieces ofmetal together by heating the filler metal to a liquidstate.

A properly welded joint is stronger than the basemetal.

Welding in the field is avoided if possible due towelding condition requirement.


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Fillet weld

Most commonly used weld

Theoretically triangular in cross section

Joint 2 surface at approximately right angle to each

other in lap, tee and corner joint Lap joint in which the parts welded are in parallel

planes

Tee or cruciform joint, in which the parts welded aremore or less perpendicular to one another

Corner joint, in which the parts are also more or lessperpendicular to one another. To improve thestrength and stiffness of the joint, the outer corner isnormally butt welded.


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Plug and Slot Welds

Slot and plug welds are seldom usedin building structures. Theyprincipally prevent buckling orseparation of lapped plates.


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Spot weld

Spot welds are seldom used in buildingstructures. The parts to be joined, which

must be thin, are clamped together by twoelectrodes. A current passing through theelectrodes melts the pieces locally, and theclamping pressure forces them together,

forming a fused spot. A line of such spotsconstitutes a joint.


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Butt Welds

A butt weld is made within the cross-section of the abutting plates in abutt or tee joint. Normally, the plateedges have to be prepared beforewelding. In some cases, if the plate

thickness is less than about 5mm,edge preparation can be avoided.


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Groove weld

Are specified when a fillet weld is notappropriate for the job

The configuration of the pieces maynot permit fillet welding

A strength greater than that provided

by a fillet weld is required Made in the space or groove between

2 pieces being welded


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FIRE PROTECTION

The materials used for fire protectionof structural steelwork may begrouped as:

Sprayed coatings

Board casings

Preformed casings

Plaster and lath Concrete, brick or block casing


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FIRE PROTECTION (Contd)

Sprayed Coatings This method used spray to spraying on the surface of

structural steel sections to provide fire protection and it is alightweight coating.

This is one of the cheapest method of providing a fire

protection coating or casing to steel for protection up tofour hours, depending on the thickness of the coating. These material is generally coarse textured and because the

lightweight nature of the material, these coating are easilydamaged by knocks and abrasions.

Spray coating may be divided into two broad groups as: Mineral fibre spray coatings Vermiculite / Gypsum / Cement spray coatings


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Board Casings

Board casing may be grouped as the type of theboards that are used:

Mineral fibre boards or batts

Vermiculite / Gypsum boards Plasterboard

For these board casings to be effective as fireprotection they must be securely fixed around thesteel section and joints between boards must be

covered, lapped or filled to provide an effective seal tothe joints in the board casing.

These board casings are not suitable for external usebecause easy damaged by knocks.


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Preformed Casings

These casing are made in preformed L or U shapesready for fixing around the range of standard columnor beam sections respectively.

These boards are made of vermiculite and gypsum, orwith a sheet steel finish on a fire resisting lining.

The vermiculite and gypsum are screwed to steelstraps fixed around the steel section and the sheetmetal faced casings by interlocking joint andscrewing.

Preform casing need a neat ready finished surfacewith good resistance to knocks and abrasion.


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Plaster and Lath

One of the traditional method for fire protection

Expanded metal last is stretched and fix to stainlesssteel straps fixed around the steel section with metal

angle beads at arrises. The last is covered with vermiculite gypsum plaster to

provide an insulating fire protective casing that istrowelled smooth ready for decoration.

This type of casing can suffer abrasion and knocks

and suitable for using at ceiling and walls.


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Concrete, Brick or Block Casings In-situ cast concrete casing is the traditional method for fire

protection and corrosion for structural steelwork. Highly resistance to damage by knocks and prevents the concrete

spalling away. The disadvantages of this type is increases the dead weight of the

frame and cost on site labour and material in formwork. Brick casing used where brickwork cladding are permanent part of

the building where the brick casing is used for appearances sake tomatch surrounding fairface brick.

Expensive and labour intensive operation where need to cut andbonding of break around columns.

Blockwork use as economic means of casing columns where

division or wall are built up to structural steelwork. Labour in cutting and bonding these larger unit is considerably less

than bricks The block encasing steelwork is reinforce by steel mesh or

expended metal lath.


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CASE STUDY


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GIRDERS

They are hot rolled sections

The main girder size for the buildingis 450mm x 225mm.

For this case study, the secondarygirder has two sizes. The size is225mm x 150mm and 150mm x115mm.

The size of cantilever beam is 450mmx 225mm and 225mm x 150mm.


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STANCHION

The stanchion is using hot rolledsection.

The common size of the stanchion onthis building is 200mm x 140mm.


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FASTENING METHOD

Methods that are used to fasteningthe joints of the structural steelmembers of this building are bolting

and welding.

But only a few frame members areproperly welded while most of the

structural members are properlybolted.


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FIRE SAFETY

Dahlia 1 college fire protection forsteel structure frame by using spraycoatings and concrete box.

Most of the beams are sprayed withthe coating, while columns areprotected by concrete casing.


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CONCLUSION


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THANK YOU

Steel Strucuture

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