Pre-engineered buildings

Rushank Mishra Gyandeep Jaiswal Akshay Gupta

-2008BARC012 -2008BARC065 -2008BARC073

Pre-Engineered Building (PEB�s)� A Pre-Engineered Building is a metal building that consists of light gauge metal standing seam roof panels on steel purlins spanning between rigid frames with light gauge metal wall cladding. It is a relatively flexible structure vs. a conventional steel framed building. In other words, it has a much greater vertical and horizontal deflection. The intent for this publication is to recognize the nature and limitations of pre-engineered. � Pre-engineered building concept is widely used in many of the industrialized countries. It consists of a complete steel-framed building system, with components pre-designed to fit together in a vast variety of combinations to meet the unique requirements of specific end uses.

Different members in the assembly of the preengineered buildings1. 2. 3. 4. 5. 6. 7.

Eave strut Roof panel Roof purlin Rigid frame rafter Ridge line End wall Wall panel

8. 9. 10. 11. 12. 13.

Side wall Rigid frame column Downspout Gutter Ridge panel Cable bracing or rod bracing(at roof and wall)

Terminologies in Pre-Engineered Buildings� Base Plate A plate attached to the base of a column which rests on the foundation or other support, usually secured by anchor bolts. Butt Plate The end plate of a structural member usually used to rest against a like plate of another member in forming a connection. Sometimes called a split plate or bolted end plate. Bay The space between frame centre lines or primary supporting members in the longitudinal direction of the building. Brace Rods Rods or cables used in roof and walls to transfer loads such as wind loads, and seismic and crane thrusts to the foundation. (Also often used to plumb buildings, but not designed to replace erection cables.) Clear Height: This is the distance between the Finished Floor Level to the bottom of knee joint. Roof Slope (x/10): This is the angle of the roof with respect to the horizontal. The most common roof slopes are 0.5/10 and 1/10. Any practical roof slope is possible.

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Typical Pre-Engineered Building Assembly� The �Rigid Frame� assembly is the most common frame used in preengineered buildings. Basically, the rigid frame consists of a structural steel (hot-rolled) moment-resisting column and beam assembly that carries the coldformed roof purlins (usually �Z� shaped) and wall girts (usually �C� shaped). In addition, diagonal rod bracing is required in the walls to resist horizontal loading on the building (i.e., wind loads and/or seismic). Rod bracing is also provided within the roof framing to resist "racking", or twisting of the building.

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DIFFERENT TYPES PRIMARY FRAMING SYSTEM

MEZZANINE FLOOR

NORTH LIGHT

MONITOR TYPE

CANOPY

DETAILS of FITTINGS

PARTITION

SIDEWALL ROOF EXTENSION

MEZZANINE AT ENDWALL

ENDWALL ROOF EXTENSION WITH SOFFIT

CURVED EAVE WITH PROJECTION

CURVED EAVE WITHOUT PROJECTION

TYPES OF PURLIN

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Z-Section Purlin used in the roofing at sports complex, MANIT

Pre-Engineered Building Process

These are the stages which are involved in the Pre-Engineered building

ADVANTAGES1. Fast Project Construction: - Buildings are fabricated and delivered within a short period due to standardisation. - Fast erection because all members are field bolted. 2. Functional Versatility: - Modular construction. - Large clear Spans (up to 100m). - Long Bay Spacing (up to 13m). - Buildings are easily expandable on all sides (allowing for future expansion). 3. Architectural Flexibility: - Aesthetic features such as fascias, parapets and curved eaves greatly improve the appearance of the building. - Readily available interface details between steel and other materials (glazing, block wall, curtain wall, etc.). 4. Low Maintenance and Operating Costs: - Virtually no maintenance required for all panels. - Roof requires only periodic cleaning. - Annual washing of Eave Gutters. - Watertight roofs.

Possible Disadvantages1. Relatively short life-span 2. Sometimes has an �industrial� or �warehouse� look to it 3. The foundation system is NOT designed by the manufacturer 4. On-site alteration in design can�t be done.

Application of Pre-Engineered Buildings� � � Commercial buildings Auditoriums and Halls Administration buildingsAirport Factories

Mall

Processing mills

Warehouses

Stadiums

Animal feed sheds High rise buildings

Shipyards

Case Study: Sports Complex, MANIT, Bhopal

Ridge Line

Flange Brace Angle

Warehouse, Mandideep, Kirby Building SystemsI-Section Column C-Section Purlin Z-Section Purlin Diagonal bracing

Foundation

I-Section Column Base Plate

Diagonal bracing for addition supports

Roof Panel

Bolting at base plate

Warehouse, Samashgarh, Bhopal

Some of the significant advantages of PEB buildings over conventional buildingsPEB BuildingsAesthetically appealing appearance Reduced time because of international design standards & codes using standard sections and connections

Conventional BuildingSpecial aesthetic design required Increased design time due to scratch and availability of less design aids

Higher resistance to seismic forces due to low weight Rigid heavy weight structures not suitable for seismic flexible frames zones 30% less PEB steel structures weight through efficient use of steel Factory controlled quality High weight due to excessive safety factor and the usage of heavier steel sections Every project to be fabricated at site

Lower initial cost of peb steel buildings(cost per Special design and features developed for each square meter about 30% less than the conventional) project at higher costs and faster delivery Simple Foundation, easy to construct and light weight of PEB structures Average delivery time 6-8 weeks Extensive heavy foundation Average delivery time 22-28 weeks