SRT251 Group Project FINAL

7/29/2019 SRT251 Group Project FINAL

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SRT 251 Construction and Structure 2Project 1 : Construction Research

TEAM members: Hideto ChijiwaMakiko IkedaPhil RogersShaun ElyYenny Kusuma


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PORTAL FRAME

PORTAL FRAME definition;Portal frames are single storey, single( or multi-bay) frames with pitched or flat roof. Fabricated fromuniversal beams, it is an ideal structural solution in many circumstances, regarding its economic and

structural efficiency. The system is specially ideal for industrial buildings due to its ability to span largeareas of unobstructed open space within its building envelope. This is made possible through the designand use of refabricated steel sections. Technological advance in the footing system also cooperate for thelarge span achieved due to their ability to carry greater loads (or its efficiency to transfer and distribute theloads to the foundation).Three major elements are; cladding for both roof and walls; secondary steel to support the cladding andform framing for doors, windows and the like; and the main framework of the structure, including allnecessary bracing. In addition, the building requires appropriate footings designed to transmit all the load

to the foundations( supporting soil).


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The design is essentially to provide a structure which iswithout, or has a limited number of internal columns, inprinciple the requirement is for the construction of fourwalls and a roof for a single or multi-bay structure.Light latticed portal frame structure for the roof of anindustrial buildings provide a neat efficient structure whichis simple to design, economic to execute and frequentlysatisfies architectural requirements.

Portal frame structure 26m-span located in

the breakwater st. Industrial area in Geelong.


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FOOTINGS

Due to the point loads applied to the foundation, Pad footings are respectablythe most suitable in long-span portal frame construction. Also in achieving aworkable surface and the distribution of loads to the foundation, combinedconcrete slab would be used along with the Pad footing. The reinforcementsand metal dowels also play a big part in the sufficient footings behaviour.

Concrete Pad Footing

Strip or combined column footing


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There are 3 types of connection systems for a Portal Frame structure.

Rigid base 2 pin 3 pinThe 3 types mentioned above are of purely how rigid or flexible the connections are at the apex, knee,

and the base. This however relates greatly to the load transfer of the structure, as the bending momentbecomes a big issue. Rigid bases are used much commonly in the current construction due to its abilityto carry the bending moment and axial loads, thus giving the framework a much lighter finish. (Maxbending moment at the knee, apex and base)Pinned bases however transmit the bending moment straight through to the foundation. (maxbending moment at the apex and knees for the 2 pin, max bending moment at the knee for the 3 pin.)

FIXED BASE CONNECTION PINNED BASE TO PORTAL


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Diagram- shows the difference in the base, rigid and pin. Georgiou, Jim.Construction & Structures 2 READER, DEAKIN University. The advantage of using steel as the

material is due to the ability to designrelatively light, long-span, durable, and is

easy to erect safely and quickly.A primary requirement is flexibility ofplanning which results in a demand for asfew columns as possible. The ability toprovide spans up to 60m (most commonlyaround 30m), using steel has proved verypopular for commercial and leisure

buildings. The lightness and flexibility ofthis kind of steel structure reduces thesizes and the costs of foundations andmake them less sensitive to thegeotechnical characteristics of the soil.

The structural envelope are simple, it isessential to ascertain correctly the load

applied to the structure and to predict theload paths from the load applied throughto the foundations.(e.g. Sheeting to the purlins and side rails,through the roof girder to the column andfinally to the foundation and supportingsoil.


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THE BENDING MOMENTS-

PURLINS and RAFTERS; Purlins and Rafters are the essential beams that make up the portalframe structure. Purlins are the beams that run the length of the frame connected to the rafters,

the purlins are bolt connected by the cleat that is welded to the rafter. The purlins are directedtowards the apex with a pitch to achieve the best possible performance. The size of the sectionsof these beams is specified by the engineer, along with the size of the web and flange,depending on the spans and load derived from the design.

EAVES connection;The eaves connections are in many different forms and changed forms throughhistory of construction. Originally the diagonal connection plane was considered,however there was a major stability problem at the inside corner.

Tapered portal frames fabricated by automatic welding can be utilised to

create aesthetic and economical industrial buildings.The behaviour of fabricated sections with slender webs is more complex thanthat of rolled sections; the resistance checks must take account of localbuckling, cross-section distortion and the interaction between the primary andsecondary structure through the stays.


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LONG SPAN TIMBER STRUCTURES:

Long-span structures( span 30m orgreater) can also be constructed usingtimber (mainly plywood) as the material.

Long-span structures require a level oftechnical sophistication that indicates aconfidence in timber as a structural andaesthetic medium on the part of thedesigners.The spanning potential of timber portalframe structure can reach around 50metres, and provides an extremely

economic solution.


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diagram- a typical plywood gusset (solid section).P.J. Yttrup & Associates Pty. Ltd. Australia.

diagram Timber portal frame structure@Mt Gambia, SA.Accessed

April 2004. http://oak.arch.utas.edu.au/projects/aus/207/istos.html

By collaborating steel knee joints with glue-laminated Timber products, Timber portal frame

structures to form large-span structure can be produced. The economical aspect of this material cannot be surpassed.

The Plywood Gusset

The Steel Plate and Dowel Knee Joint Bracket; although this is not a timberproduct, it is used in conjunction with timber columns and rafters to provide asteady connection system.The various timber products used in those of Timber Portal Frame structures

are;
http://oak.arch.utas.edu.au/projects/aus/207/istos.htmlhttp://oak.arch.utas.edu.au/projects/aus/207/istos.html


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TIMBER PORTAL FRAMEconstruction process:

Yttrup, Peter. Ham, Jeremy, Deakin University Construction and Structures 2SRT251 LECTURE powerpoint slides.

DURING CRANE LIFTING THE STRUCTURE;the rafters, purlins and roof bracing are fabricated onthe site, the roof is then lifted on and joined to thecolumns (this process can be done as a whole, or bysections).Elements such as the gussets and purlinsare then installed. All purlins should have allconnections installed, including joist brackets,tension straps and fly braces. The rest of the majorconnection joints such as the knee gussets must alsobe fixed along with required bracings. Temporarybracing is also fitted, due to the support the structure

needs when the support from the crane is released.

AFTER CRANE DETACHED;After the cranes are detached, the remainder of thefixing/nailing takes place, this is when the detailedinstallations are carried out, such as; girts, eaves,mullions, remaining purlins and additional roofwind bracings.

Though Timber being a highly economic solution instructural frames, it is also highly flammable andprone to elemental attacks, and due to the naturalproperty of the material, it needs to be tested beforeany type of work is done to check the performance ofthe timber. The tests include trial fabrication andtreatments (paints and chemical protection coatingmust be applied before the erection).


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Spatial requirements of the client:The selected system provide the client with adequate space to utilise the floor space according to theirbusiness needs. As buildings will often change hands throughout their working life, a re-fit of thewarehouse and/or office space may be necessary. Structural members with significant spanning capacity

allow the occupant to carry-out such activities without the expense of making structural alterations.

Appropriateness of steel portals in this issue.Steel has extremely high material strength in both compression and tension. With a Youngs Modulus of200,000Mpa, it is by far the stiffest of all conventional building materials. These two characteristics of steelare most exemplified in the design of universal beams and columns. Universal beams have excellentspanning capacity, making their application in portal frame construction the most desired framing option

for medium-sized industrial construction. (Mcleod, 2003)

Appropriateness of saw-tooth construction in addressing issue.Saw-tooth trusses were used in close span construction, which was prevalent prior to the mid 1970s. Unlikeportal frames, buildings with saw-tooth trusses had to be designed in a series of bays, supported by load-bearing columns. Such design is far more restrictive than portal framing in allowing spatial freedom to theend user.

Adaptability of the structural system to a variety of site conditions.Structural systems that can be constructed in extreme conditions are likely to be popular with buildingdesigners. On sites with high, extreme or abnormal moisture conditions, differential movement may causeexcess structural deflection. This can adversely affect the aesthetic quality of the building, leading to costlyrepair work.


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CONCRETE CONSTRUCTIONTilt-up and On-site Casting

System characteristics

The most common characteristics of tilt-up construction include:Building Quality: Tilt-up construction structures require the latest technology, experienceddesign and construction professionals.Speed Of Construction: Due to the systems engineering and assembly lieinvolved in tilt-up construction, productivity then provides savings in time and labour.

Economy: Very economic as it provides alarger amount of building, operating and

investment for your dollar.Design Freedom: The beauty of tilt-updesigned buildings, is that they create astructure that suits and is sufficient for anypurpose or taste.


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Versatility: Tilt-up wall panels also make it very simple to create a building that is easilyrepositioned in order to provide new openings or other building additions.

Financing: Tilt-up-built structures have proven to be a more attractive investment tolending institutes due to their lasting value.

Resale: Concrete buildings much easily retain their appearance, structural integrity and,most importantly, their value.

Infiltration Factor: Tilt-up constructed buildings are air-tight. This enables the building tosave on heating and cooling loads, and the size of mechanical units.Reduced Maintenance: Building maintenance costs are reduced because of the rugged

durability of concrete, and its practical construction detailing.

Floor Utilisation: Because tilt-up construction requires no columns inside the building,there is unrestricted space for door locations and rack spacing.

Security: The steel reinforcements in the concrete provide a deterrent for potential illegalentry.

Noise Abatement: The sound abatement properties of concrete make an efficient soundproofing.

Thermal Economy: Energy costs can be minimised due to the natural heat-sink propertiesof concrete.


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System application

Prepare for castings: When producing tilt-up panels, factors that need to be considered include, mostimportantly, providing a suitable casting bed/ slab for the panels. The surface must be a sound, dense,smooth concrete surface. Then follows the essential elements such as; creating an effective mix design

(concerning the use of fly ash and water, if needed), the use of moisture barriers, considering thetemperature at the time of placing, vibration of the concrete, and being sure of sufficient properfinishing and curing techniques. (Tilt-Up Construction,1989)


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Form work:Formwork is a temporary structure, that acts as a stencil, to form a sand bed,for the pouring ofthe concrete, in order to create the panels. Basically, timber planks are temporarily positionedoutlining the perimeter of the desired structure, then used to hold the poured concrete inposition as it dries, forming the panel.

Bondbreaker:A vital part of the panel construction, is selecting a sufficient curing compound and bondbreaker.Factors to be considered when choosing an appropriate bondbreaker include; a product thatperforms both the curing and the bondbreaker (to ensure compatibility between the materials),weather conditions (rain and heat can effect the bondbreaker), durability of the bondbreaker,whether or not the panels will be painted (in this case, bondbreakers that leave a paintable surface

are available), whether or not the panels will be exposed (because bondbreakers leave stains), and,will floor treatments be needed.

Lifting- Inserts:The location of lifting inserts should be used in instances where strongbacks are used, where the panelis of a large size. These are positioned in accordance to where the rigging equipment is needed inorder to lift the panel safely off the ground without damaging the panels. The inserts are required soas the crane can then be connected to the panel easily when it is time for lifting.

Bracing and Bracing Inserts:Braces are needed to help resist wind and construction loads. Where an applied loadis apparent, three bracing inserts are essential, and generally, a minimum of twobraces are needed for a single panel. These are usually placed on the same side aslifting inserts. (Code Of Practice Tilt-Up Construction, 1985)


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Joining: There are usually two types ofconstruction joints; those that allow relativemovement, and those that do not. Joints arerequired where a break in concrete pouringoccurs, at planned joint locations, they are

to coincide with expansion joints,remembering that faulty joints can lead torusting on the reinforcement.

Vertical joints include: mechanical key,dowel bar, reinforcement mesh and wire-brush joint/ scabble back concrete.Horizontal joints are to be placed between

columns, slabs or beams.

Control joints are used to create a plane ofweakness, and cause the concrete to crack inthe desired area. Other joints include:Expansion joints, Isolation joints andWatertight joints.

A contraction joint is used so as twoconcrete surfaces are able to move awayfrom each other as a result of shrinkage etc.

ISOLATION JOINT

SAW CUT CONTRACTION JOINT


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FACE SEALED JOINTS COMPRESSION SEAL


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Benefit of cast on-siteNo transport costsLimits useability of floorEasier liftings

Can be load bearingNo columns Benefits of Tilt-up

Cost effectiveSpeed construction - Reduced labour cost

Ease of construction- factory process on siteDurability-compare with metal systemfailures and accidental damageSecurity- used for prisonsFire resistancePlusSound reduction 50db v,30 metal skinArchitectural expression new and versatileEnergy conservation: thermal massLow maintenance and cost


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Building Applications

Step 1"Parameter Formwork": The desired panel thicknessis fixed to the casting surface, this is done includingany openings or features. A coating of bondbreakeris applied, in a spray form, to the concrete andformwork.

Step 2"Reinforcement": Reinforcement is fixed withinthe forms, also using the required lifting andbracing inserts. The concrete is then poured,

followed by being vibrated, screeded and thenbull floated.


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Step 3The concrete is then trowelled finished, by hand and

power. Followed by a spray-applied cure coat.

Step 4

This process is then repeated once more for all panelcasting, using climbing framework.

Step 5All concrete is then cured, the formwork isstripped, the building's slab is prepared, and thelifting equipment is organised to arrive. The firstpanel is lifted, set, and temporarily braced.


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Step 6The rest of the panels are then tilted fromtheir stacks, transferred, set and braced.

Step 7

The crane, then, is placed in a singleposition and working limits,where it canlift and set all panels.

Step 8All panels are lifted within one day, andthe structure is now ready forintermediate floors, roofing system andfinal wall decoration to be fixed for

completion.


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Advantages: Lightweight. Offer pre-finished options. Provided a range of materials option,

finishes, appearance options andmaintenance requirements.

Prefabricated Rigid finishes

Disadvantages: Just suitable for regular rain washed area

or unless needs regularly clean. Not be able to composite with other

materials- contact between dissimilarmetal can lead to galvanic corrosion.

Transmit roof noise from heavy rain orhail- unless sound insulation material isinstalled under the roofing.

Provided little or no thermal insulation

benefit- the roof spaces will heat up andcool down rapidly

METAL CLADDING


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Cladding Materials

; manufactured by dipping the mild steel in a hot solution of

45% zinc and 55% aluminium alloy followed by a

chromate wash to protect the steel form corrosion

Advantages: Offers a wide range of profile (e.g.: curve) and finish

options.

Fast fabrication as it can be supplies in long lengths

Its nature color , silver-grey , dulls slowly whenexposed to the weather.

Provided the corrosion protection, best durability.

Disadvantages: Not suitable to use as a walking surface on the roof

High cost materials.

1.1Zinc Aluminium Alloy-Coated Mild Steel

Fig 1 Zinc Aluminium Cladding


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Formed by melting of ores which

contain the zinc blend followed by

rolling to form a sheet

material. Zinc is described as either

commercial (pure) zinc or as alloycontaining small amounts of copper

and titanium to improve tensile

strength and creep strength.

1.3 Zinc

Advantages: Better durability on steeper pitched roofs,

because of better rain washing Recyclable Suitable use to form roof accessories andornaments corrosion-resistance can be pressed to form a tile shape

Disadvantages: Limited range of profile and finish options Reform at cold temperatures; become brittle Impurities in the zinc can cause theformation of localized small holes.

Advantages: Easily worked into shaped (complex and

curve)and for forming joints

Recyclable Excellent corrosion resistance in most

environments. Excellent performance at high wind loads

area.

Disadvantages: Very low maintenance. Requires specialized installation skills and

procedures- cost and time considerate. Low fatigue resistance ( can crack where not

free to expand or contract). Heavyweight . No thermal insulation.

1.2 Lead

99% pre metal which may contain very smallamounts of copper, silver and tellurium tostabilize the movement properties of thelead. Sheet lead roofing is manufacturedby milling, hand casting, and machine casting.

1 4 Aluminium


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Advantages: Offers a wide range of roof slope

and profile options.

Lighter and more durable

Ductile, malleable and corrosion-

resistance. Fast fabrication.

Excellent performance in differenttempers.

Disadvantages: Sensitive with acids and strong

alkalis materials

Easily damage by poor storage priorto installation, severe hail storms,being walked on during and afterinstallation.

Impurities lead to perforation.

1.4 Aluminium

Fig 7 Aluminium Cladding

1.5 Stainless Steel; are iron alloys which contain at least 12% chromiumand have controlled concentrations

of other elements.

Advantages:- offer a wide range of profiles

and finished options, includingfactory coated

- Fully supported sheets, whereit can be jointed by welding

or with specially designededges incorporating a self-

draining joint.- Great corrosion-resistance

Disadvantages:- Low maintenance- More difficult to form on-site

than copper, lead, aluminium or

zinc


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Roof Cladding Selection:

According to the Design considerations( the environment issue andperformance), aluminium cladding became the best solution of roofing forthe warehouse and showroom design.

The roof geometry for the warehouse and showroom are quiet simple;2 pitch roof

surrounded by gutter (roof drainage). In this case, Aluminiumwould be able to cover up the design requirement. It is much costeffective than others steel-based cladding ( lead, copper ), moredurable, and available in a wide range of forms ( such as;guttering, downpipes ). The nature color of aluminium; lightgrey with either a smooth or orange peel surface, is suitable

for the industrial environment. Properties of aluminium cladding arelightweightthan the others, approx. 2.3 kg/m with typical thermal movement0.023mm/m/C.


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Specification product of Roof and Wall cladding:

Lysaght, KLIP-LOK 406

Materials specification:; Metal base with 0.60 mm BMT thickness

; contain 2.82 kg/m masses

; available with the COLORBOND pre-paintedsteel complies with AS/NZS 2728-1997.

Maximum support spacing:; 3600 mm c/c span

; based on testing in accordance with

AS1562.1-1992, AS4040.0-1992 and

AS4040.1-1192

Fig 9 KILP-LOK 406


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Wind pressure capacities:

; 1.67 kPa

; Testing was conducted in accordance with AS 1562.1-1992 Design and Installation

of Sheet Roof and Wall Cladding- Metal, and AS4040.2-1992 Resistance to WindPressure for Non-cyclonic Regions.

The rigid shape of an inflated Its direct pressure rig uses no air

airbag does not apply pressure bags and applies pressure uniformly

to the ribs of secret - fixed over the entire profile- including the

cladding or adjacent to support ribs.

Uniform pressure distribution of our direct pressure rig which accurately reproduces

the wind conditions experiences in the field.


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INSTALLATION:

STEP 1

When lifting sheets lengths onto the roof frame

ready for installation, make sure all sheets have

the overlapping ribs facing towards the side

where fastenings to commence. Fasten clips to

the purlins at each of the sheet, having positionedso that the first sheet will be in correct relation to

other building elements. Align and fasten the

remainder of the first run of clips using a string

line or the first sheet as a straight edge

The first sheet set longitudinally in relation to gutter

overhang and locates it over the fastened run of

clips, positioning the centre rib first, and engages

the centre and overlapping ribs onto all clips by foot

pressure

STEP 2


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STEP 3

Position and fasten the next run of clips, one

to each support, with the short return leg of

the clip over the underlapping rib of the

installed sheet. The spur can be flattened

with a blow from a rubber mallet to seat

down over the ribs, if the clip fouls one of

the spurs spaces along the outer free edge of

the underlapping rib.

STEP 4

Place the second sheet over the second run of clips,

again positioning the centre rib first. A string line

stretched across the bottom alignment of the sheets canbe used to check that the ends of the sheets are in line.

Fully engage the interlocking ribs and the centre rib over

each clip. Apply foot pressure to the top of the centre rib

over each clip. For complete interlocking, along the

underlapping rib must be fully engaged in the shoulder

of the overlapping rib. When engaging the interlocking

ribs, stand only on the sheet being installed, that is

the overlapping sheet, and not on the preceding sheets.

Make periodical checks that the installed sheets are

aligned with the roof perimeter.


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STEP 5

a) If the space left between the last full sheet and

the fascia or parapet is more than a half sheet

width, a sheet can be cut longitudinally, leaving

the centre rib complete.

This particular sheet can be fully

clipped onto a row of clips as for a full sheet,before installing the capping or flashing.

b) Otherwise, it can be covered by the capping

or flashing if the space left between the last full

sheet less than a half sheet width .

In this case,the last sheet should be secured by

cutting clips in halves and fastening the

underlapping rib at each purlin with a half clip.


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CRITICAL KEY-POINTS:

The selection/choice in choosing the right members in the structure (beams, columns,and connection details) depends largely on cost. Economic approach towards the

construction of the building is an important aspect but keep within the functionalconstraints.The factors that needs to be considered when working out the width or the span of thewarehouse are:Amount of load capabilities of the purlins and girts used, this is determined by thebeam-size and the material.Footings and foundation capability, the soil-condition plays a large part as it must be

able to accommodate the column loads.The size and the material of the cladding/envelope system.

BRACING;Bracing is an important issue within a portal frame structure, as long-span structuresneed considerable amount of bracings in response to the wind loads applied. Angle

bracings and rod bracing can be considered, however angle bracings would be a mucheconomical solution, and as rod-bracings have tendencies to sag, cross bracingstherefore provide a much practical bracing system for this type of structure.In designing warehouse structures of long-span characteristic, the main factorconsidered is to fulfill the functional(/structural) requirements with regards to theeconomical view( cost). This can be solved by the standardization of the frame byincorporating beams and columns of similar characteristics (size, mass, density).


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Design proposal : Warehouse

The warehouse building is approximately45m x 35m of concrete pad footing withconcrete slab,fitted with a metal sheetcladding with clip-lock roof system.The

main access to showroom and officebuilding is via a side pedestrian access door.

The long-span warehouse; span 40m wasdesigned on the site provided, thewarehouse provides an automobileshowcase area and a maintenance facility

included within the warehouse. [includediagram of schematic design of thewarehouse along with the site plan]


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SHOWROOM/OFFICE


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STRUCTURAL MEMBER SIZE:

Type of members Size (mm) Max span / size Weight Location

460 UB ( BHP) 450 x 190 9520mm 74.6kg/m Portal frame

360 UB ( BHP) 350 x 170 6470mm 50.7kg/m Column in office building

250 PFC ( BHP) 250 x 90 4520mm 35.5kg/m Roof purlins in both buildings

16 UA ( BHP) 150 x 90 3550mm 27.9kg/m Eaves strut in office building

Metal sheet ( Lysaght) Zincalume 0.6 mm thickness 3600mm 2.82kg/m Minimum roof pitch 1 degree

Concrete panel 150mm thickness 7000mm x 6000mm 0.36t/m2 Cladding in office building


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RIGID BASE CONNECION

BASE PLATE BOLTS


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HAUNCHING DETAIL

STIFFENED RIDGE CONNECTION


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OFFICE STRUCTURE Construction Process

Concrete Flooring systems


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g y

TILT-UP SLABS:

The tilt up wall system is a site pre-cast method of buildingconstruction. Slab dimensions areapproximately 10 metres high, 10metres wide and 190 mm inthickness. These slabs weigh

upwards of 15 tonnes.

Tilt-up slabs are held at their basein a trench at or below floor leveland secured at their base by noother means. The upper

section of the slabs are attached bymetal bolts to a metal plate, weldedto rolled steel joists (RSJ), formingthe roof support structure of thebuilding.

PRE-CAST PANEL AND SLAB FLOORING FIXINGS

RAFT FOOTING with CONCRETE FLOORING


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RAFT FOOTING with CONCRETE FLOORING

BEHAVIOUR OF TILT-UP SLABS IN A FIRE SITUATION:

Structural steel will rapidly loose strength when subjected to heat (A 56% loss of strengthwill occurs at 593 Celsius); As this happens, collapse can occur within 5 to 10 minutes.

Further, Steel roof beams when heated will expand and may push walls outward.The direction of slab fall may also be governed by the performance of the roof, subjected toheat and fuel loads from within the building.

CASE STUDY


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STRUCTURE ONELeopold Primary School: Multi-Purpose Facility.

Address: 1 Kensington Rd, Leopold.Builder: Lyons Construction, Fyans St, South Geelong.Structural details:

Super-structure: Steel portal frame on pad footings. Footings in main hall are concrete padssupporting a timber-framed sub-structure. Non-load bearing timber-framed walls divide up the office space.Stiffened raft slab footing used in performance and office areas.

Building Envelope: Corrugated iron roofing throughout structure. Corrugated iron wall cladding

enclosing main hall. Masonry cladding enclosing office space and performance area.

Critical review of structures:

The purpose of the following section is to critically analyse thealternative structural systems that may be deemed as suitablefor the design of medium-scale warehouse and office spaces.

In the course of conducting research for this review, advise wassought from a reputable local building professional withextensive experience in this area of construction. Informationdrawn from interviews with this professional, along withvarious textual sources, will form the basis of this review.

The content of the review will centre on the followingincomplete structure, which have been observed over the lastmonth. Another two types of structural systems will bereviewed, these are; Timber portal framing and steelconstruction with saw-tooth trusses.

Steel portals.


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p(1) Steel has extremely high material strength in both compression and tension. With a Youngs Modulus

of 200,000Mpa, it is by far the stiffest of all conventional building materials. These two characteristics ofsteel are most exemplified in the design of universal beams and columns. Universal beams haveexcellent spanning capacity, making their application in portal frame construction the most desiredframing option for medium-sized industrial construction. (Mcleod, 2003)

(2) Portal frames- footings systems.Reference to pads in hall. Good for athletic facilities not for warehouses. Pad footings, such as thoseused for the hall in Structure 1 are prone to differential movement. The pad footings and strip flooringused in this case will provide greater comfort to the facilities users, than would the harder surfaces ofraft slabs. Such issues are not of concern in the design of warehouses. Of more importance, is providingsupport to the immense live loads that will be imposed on the structure, such loads would onlycompound the problems caused by differential movement. Saw-tooth trusses were used in close span

construction, which was prevalent prior to the mid 1970s. Unlike portal frames, buildings with saw-tooth trusses had to be designed in a series of bays, supported by load-bearing columns. Such design isfar more restrictive than portal framing in allowing spatial freedom to the end user.

Issues critical to the selection of structural systems for warehouse and office spaces


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Pre-cast/InsituStructural systems with pre-cast insitu wall panels as load-bearing members are inwide spread use in industrial construction. Rafters are bolt-connected to fixing plates,which are connected to the reinforcement and cast into the panel.

The spanning capacity of such systems is comparable to portal framing, with the sizeof wall members increasing in accordance with the roof loading.

Saw tooth constructionSaw-tooth trusses were used in close span construction, which was prevalent prior tothe mid 1970s. Unlike portal frames, buildings with saw-tooth trusses had to bedesigned in a series of bays, supported by load-bearing columns at close span. Such

design is far more restrictive than portal framing in allowing spatial freedom to theend user.

Timber PortalsTimber Portal frame construction may be designed span the same distances as steelportals.The nailing pattern that is used in timber portal connection systems is far morecomplex than the rigid bolting system used in steel portal connection.

Issues critical to the selection of structural systems for warehouse and office spaces

Spatial requirements of the clientThe selected system provide the client with adequate space to utilise the floor space according to theirbusiness needs. As buildings will often change hands throughout their working life, a re-fit of thewarehouse and/or office space may be necessary. Structural members with significant spanning

capacity allow the occupant to carry-out such activities without the expense of making structuralalterations.


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Steel PortalsThe hot-rolled, mild steel used in portal framed construction s renowned for its durability. The

material maintains its stiffness over long periods of time, making it the least susceptible to timedependent creep deflection. This allows steel structural members to be recycled after buildingdemolition.

(Ham, 2003)

Pre-Cast/Insitu.Reinforced concrete wall panels, like all concrete products, must be carefully manufactured toensure that durability can be maintained over long periods. All reinforced concrete panels mustundergo surface treatments to guard against chemical attack and to water proof the material.Steel, however is a naturally occurring material and its manufacturing process is far more

simplistic than that far concrete.

Saw-tooth truss construction.One major disadvantage of using saw-tooth truss systems, was the need for a box gutterdrainage system in the truss troughs. The box gutters were prone to leakage, which wouldoften occur within the main work area, and thus required frequent maintenance. In portalframe construction, storm water drains to gutters that run parallel to the external wallsperpendicular to the rafters, reducing the likelihood of leakage.

Durability of the structural material throughout the buildings life-spanOf paramount importance to building designers and clients, is the likely cost of

maintenance works throughout the working life of the building. Materials used in modernconstruction, such as steel, timber and concrete, have diverse compositional properties and differ inhow they are affected when sustaining prolonged load actions.Weather resistance also varies among the type of structures, which can be critical if the conditionsin which they exist are extreme. (Creep etc)


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Cost of the Building Materials and Construction ProcessBudgetary concerns will often be the most important factor in the choice of design

for a building client. In these situations, the building design that is the most cost-efficient, interms of materials costs and constructability will be chosen.

Steel portal framing is the most cost-effective form of industrial steel construction. It is for thisreason that saw-tooth truss construction was superseded as the preferred structural system forindustrial applications in the 1970s, when the cost of labour began increasing, in relative terms,to the cost of steel, as a result of labour market pressure. (Page, 2004)

What about constructability comparison b/w Pre-cast timber and steel portals.

References:


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Code Of Practice Tilt-Up Construction, F.D. Atkinson Government Printer, Melbourne, 1985.

Economical Structural steelwork fourth edition, Australian Institute of Steel Construction, 1996.

Ham, Jeremy, SRT251 Construction and Structures 2, LECTURE, School of Architecture and Building, DeakinUniversity, 2004.

Mortlock M., Tatham C.,Selecting Roof Cladding, Branz, (Porirua City)New Zealand,1998.

Oehlers D. J., Bradford, M. A., Composite Steel and Concrete Structural members , Pergamon, New York, 1995

STEEL CONSTRUCTION Journal of the Australian Steel Institute, volume 32 Number 4 Dec 1998, Australian SteelInstitute, 1998.

Tilt-Up Construction, Seminar Course Manual, American Concrete Institute, United States Of America, 1989.

Tilt-Up Construction, Concrete International: Design and Construction, American Concrete Institute,1982-6.

Tilt-Up Digest, Architectural Details, Steel Reinforcement Institute Of Australia, Mathieson and Mackay, 1991.

SRT251 Construction & Structures 2, Reader, School of Architecture and Building, Deakin University,1997.

Page, D, 2003: Structural Engineer, Page & Green & Associates, Information obtained through interviewconducted on the 1st April 2004.

LYSAGHT pamphlets, BlueScope Steel Limited, 2003.Internet Sources- Websites:* BLUESCOPE webpage; http://www.bluescopesteel.com.au/index.cfm* LYSAGHT info webpage; http://www.lysaght.com* TIMBER BUILDINGS in AUSTRALIA; http://oak.arch.utas.edu.au/tbia/default.asp* http://www.claycorp.com/tiltup.html* http://www.tilt-up.co.uk/* http://www.consteel.com/consteel/cshome.nsf/fsshowcase
http://www.bluescopesteel.com.au/index.cfmhttp://www.lysaght.com/http://oak.arch.utas.edu.au/tbia/default.asphttp://www.claycorp.com/tiltup.htmlhttp://www.tilt-up.co.uk/http://www.consteel.com/consteel/cshome.nsf/fsshowcasehttp://www.consteel.com/consteel/cshome.nsf/fsshowcasehttp://www.consteel.com/consteel/cshome.nsf/fsshowcasehttp://www.tilt-up.co.uk/http://www.tilt-up.co.uk/http://www.tilt-up.co.uk/http://www.tilt-up.co.uk/http://www.claycorp.com/tiltup.htmlhttp://www.claycorp.com/tiltup.htmlhttp://oak.arch.utas.edu.au/tbia/default.asphttp://www.lysaght.com/http://www.bluescopesteel.com.au/index.cfm

Documents

SRT251 Group Project FINAL