Pre–engineered Building Systems A Promising Future

Dr. Abhay Gupta, Vice President (Engineering) Era Building Systems Ltd. Noida

PEB: A New Technological Wave

Technological improvement over the year has contributed immensely to the enhancement of quality of

life through various new products and services. One such revolution was the pre–engineered buildings.

Though its origin can be traced back to 1960's, its potential has been felt only during the recent

years.

An estimated 70% of all new commercial buildings in the US are pre-engineered! There is really no

dispute in the fact that pre-engineered building systems are the new wave in construction.

Definition

"Pre-engineered steel buildings" are those which are fully fabricated in the factory after designing,

shipped to site in CKD(completely knocked down) condition; and all components are assembled and

erected at site with nut-bolts, thereby reducing the time of completion.

Pre–engineered means, generally speaking, is any part of a structure that is manufactured prior to its

arrival on the building site. The concept of the pre-engineered building (PEB) is one where the

fabrication is completed in a controlled environment with the latest technology, and then subsequent

erection is carried out.

Though initially only off the shelf products were available in these configurations aided by the

technological development tailor made solutions are also made using this technology in very short

durations.

The designs were ready-made but the building components were either ready-made or manufactured

against specific orders. These buildings were pre-designed or 'pre-engineered' into standard sizes,

spans, bays and heights, and use standard details for fixing cladding, roofing, gutters, flashing,

windows, doors etc taking advantage of industrial practices of mass production of components

economically.

Although PEB systems are extensively used in industrial and many other nonresidential constructions

worldwide, it is relatively a new concept in India. These concepts were introduced to the Indian

markets in the late 1990's with the opening up of the economy; and a number of multi–nationals

setting up their projects. The current pre–engineered steel building manufacturing capacity is 6.0 lac

ton per annum. The industry is growing at the compound rate of 25 to 30%.

With respect to design of the structure and aesthetic appearance India is way behind. Indian

manufacturers are trying to catch up; comparatively PEB is a new concept in India.

A healthy trend in the form of growth in demand for construction works in residential, Commercial,

Institutional industrual and infrastructure sectors are being seen over the past decade. Modern

Structures are much more complex and sophisticated as compared to earlier period. One of the major

changes which are being felt by all is that the present structures are taller and thinner. Modern day

requirement of structures is that these should be lighter yet not compromising on functionality. Civil

engineering construction has seen a continual economic competition between steel, concrete and other

construction materials.

Currently, the total steel production in the country is about 45Mn Ton against 1280Mn ton of world.

Per capita steel consumption in India is 42kg whereas it is 270kg in China. About 10% of steel goes to

the construction industry and amidst it PEB accounts only for the 0.5Mn ton. As on date. In the next 5

years, the steel production will be doubled and with efforts of organisations like BIS and INSDAG,

steel intensive construction may rise up to 22Mn ton. Owing to advantages of PEB, several non-

conventional segments are also getting attracted to use PEB and the potential will rise up to 2.2Mn ton

which is four to five times of today's scenario.

Subsequent paragraphs are only a humble attempt to present the various aspects of conceptual

development, technology of design and manufacture; and future growth aspects of Pre–engineered

building Industry in India along with its grey areas.

The Concept: Superiority of PEB over Conventional Construction

Pre–engineered steel buildings use a combination of built-up sections, hot rolled sections and cold

formed elements which provide the basic steel frame work with a choice of single skin sheeting with

added insulation or insulated sandwich panels for roofing and wall cladding. The concept is designed to

provide a complete building envelope system which is air tight, energy efficient, optimum in weight

and cost and, above all, designed to fit user requirement like a well fitted glove.

These Pre–engineered Steel Buildings can be fitted with different structural accessories including

mezzanine floors, canopies, fascias, interior partitions, crane systems etc. The building is made water-

tight by use of special mastic beads, filler strips and trims. This is a very versatile building system and

can be finished internally to serve any required function and accessorized externally to achieve

attractive and distinctive architectural styles. It is most suitable for any low -rise building and offers

numerous benefits over conventional buildings.

It is very advantageous over the conventional buildings and is really useful in case of the low rise

buildings. Pre-engineered buildings are generally low rise buildings; however the maximum eave

heights can go up to 25 to 30 meters. Low rise buildings are ideal for offices, houses, showrooms,

shop fronts etc. The application of pre-engineered concept to low rise buildings is very economical and

speedy. Buildings can be constructed in less than half the normal time especially when complimented

with other engineered sub-systems. Table-1 presents an overview of comparison between RCC,

Conventional steel and PEB structures.

Table-1

Good structural design of the building necessitates integration of the structure into a whole physical

system. It is necessary to understand the influence of structural design on the architectural design

and also vice versa for the development of the subsystems for power, lighting, thermal control,

ventilation, water supply, waste handling, firefighting etc. The steel structural systems have come out

more popular largely because of their ability to provide flexibility in accommodating these subsystems

in the building while allowing architectural forms.

Apart from the state of the art technology used for fabrication of pre-engineered buildings, the other

main difference is in the assembling of PEB. The varied components of the PEB are joined to each

other based on the nut and bolt methodology as against the welding and rive ting methodology used

for conventional steel buildings. Metal building technologies permit almost complete freedom to the

designer and the architect in incorporating whatever features may be needed in the building -

structural, thermal, ventilation or acoustical, to name a few.

Advantages

Pre-engineered building systems provide real value to clients without sacrificing durability, seismic and

wind resistance, or aesthetic appearance. Cost savings begin right at the drawing preparation stage.

Systems engineering and fabrication methods help reduce interim financing costs through faster

construction and minimised field erection expense. An added benefit is earlier occupancy of the facility

and a head start on day-to-day operations by the client.

Apart from costs, there is an assurance of factory-built quality and uniformity in design and

fabrication. These systems are also energy efficient; incorporate watertight roofing systems; enable

easy disassembly or future expansion and have the lowest life cycle maintenance costs.

Adding to these; there is no mess of sand and cement; power savings; walkable ceilings; progressive

and non-progressive panel systems for walls. A poor man can be provided with a home created under

strict quality control and having a longer life span, with greater safety against natural disasters like

earthquakes and cyclones.

Moreover, It is possible to create the building in required form and shape. And the 'system approach'

renders a holistic way of thinking at one platform for consultants, designers, architects, and builders.

Thus it tends to achieve a perfect harmony among various stringent specifications and aesthetic

requirements in a most economic way.

In nutshell, the benefits may be summarized as under:

Increased speed of construction, quicker return on investment

Ensured quality of material, Design and construction

Unlimited architectural possibilities

Enhanced Durability and seismic reliability

Easy construction, maintenance and refurbishing

Increased Life cycle performance and cost competitiveness

Environment–friendly structures

Better value for money

Cleaner and unencumbered sites

Sustainability in construction through reuse of most materials

Suitability for Hilly regions and other geographically difficult areas

Hassle Free

Optimized design of steel reducing weight

Better Earthquake & Wind pressure resistant.

Energy efficient roof and wall system using insulations.

Easy integration of all construction materials

The building can be dismantled and relocated easily.

Future extensions, expansion modification can be easily accommodated without much hassle.

Faster delivery and erection, saving around 30-40% of project time

Column-free large spans, up to 90 m.

Virtually maintenance free

Single-source responsibility

'Systems approach' ensures integrity and safety of all building components

Lighter weight; savings in foundation cost of 10-20 percent

Insulated from sound and heat, as per the requirement

Better rainwater harvesting through gutters and down-take arrangements

Overall economy

Diversified Applications

Almost every conceivable building use has been achieved with PEB; the most common applications are

industrial, institutional and commercial.

In India, Pre-engineered building systems find application primarily in the construction of Warehouses,

& Industrial sheds & Buildings. The recent focus has also shifted to cover Rural as well as urban,

individual and mass housing projects, farmhouses, slum re-organisation projects and rehabilitation

projects, amenity structures like health centres, kiosks, primary schools, panchayat ghars etc. The

pharmaceutical industries and exhibition centres, and functional requirements like offices, seminar

halls, call centres, supermarkets, showrooms etc. have also attracted PEB. Earthquake -resistant

buildings are the recent applications of PEB with wide and immediate acceptance.

PEB concept has acted as a catalyst in the infrastructure development of the country. Single storied

houses for living take minimum time for construction and can be built in any type of geographic

location like extreme cold hilly areas, high rain prone areas, plain land, extreme hot climatic zones

etc.

Applications of pre-engineered steel buildings include (but are not limited to) the following:

Industrial Buildings & Workshops

Warehouses

Commercial Complexes & Supermarkets

Showrooms

Corporate Office Buildings

Schools

Indoor Stadiums

Outdoor Stadiums with canopies

Fuel Stations

Metro Stations, Bus Terminals, Parking Lots

Highrise Buildings

Customized Housing

Large Exhibition Centers

And many more…

Aircraft Hangers

Labor Camps

Community Centers

Railway Stations & Railway Storage yards

Equipment housing/shelters

Telecommunication shelters

"Almost" any low-rise building

There is a great possibility of improving the aesthetic quality with a choice of roofing elements,

exterior finishes, weather-sheds, color system and variations in planning as well as massing.

Main Components

There are following major components in a pre-engineered building:

Primary or Main frame

Gable End framing or Wind columns

Secondary frame or Purlins, girts etc.

Roof & Wall Sheeting

Bracing system

Crane system

Mezzanine system

Insulations

Attachments like canopies, fascia etc

Doors, Windows, Ventilators

Accessories like Turbo vents, Ridge Vents, Skylights etc.

Main Framing

Main framing basically includes the rigid steel frames of the building. The PEB rigid frame comprises

tapered/straight columns and tapered rafters (steel plate fabricated 'I' or 'H' sections are referred to

as built-up members). The frame is erected by bolting the end plates of connecting sections together.

Secondary frame or Purlins, girts etc.

Purlins, girts and eave struts are also known as secondary cold-formed members. There is no welding

involved in their preparation. They are prepared by press bending the HR steel coil giving it the

desired shape(Z- or C-shape).

Roof & Wall Panels

Metallic plain or color coated profiled steel sheets are used as roof and wall sheeting. The steel sheets

are generally made from Zincalume or Galvalume coils in thickness range of 0.47mm to 0.55mm. The

base steel is either galvanized having a zinc coating varying from a minimum Mass of 120 gsm./m2 to

a maximum of 275 gsm./m2 (total of both sides) or a base steel coating of zinc – aluminum (zinc

45%, aluminum 55%) of total Mass of 150 gsm./m2 (total of both sides) are available with permanent

color coating. The color coating is also available in various options in polyester paint coating like

regular modified polyester, silicon modified polyester and super polyester coatings. Special organic

coatings like PVF2 (Poly Vinyl Fluoride) are also made available. These various color coatings on the

base steel with galvanized or zinc aluminum coating provides suitable resistance for various kinds of

environment hazards. Metal roofing and siding profiles can be manufactured to any length – limited

only by transportation constraints (usually to 12 meters). Lap joints with 150mm to 200mm overlap

virtually eliminate water ingress.

Profiling can be carried out at site itself with no limit in lengths. This permits a totally joint-less run of

roofing, a major advantage to the designers to create roofing with the minimum pitch. Machines have

been developed which permit rolling at the eaves level so that even the task of lifting and shifting the

rolled profiles in to position is avoided. Standing seam profiles with a pre -determined height of up-

stands can be chosen to accommodate the expected run-off of water without overflow on to the crest

of the profile.

At the initial project planning stage, roof slope is a key consideration for architects incorporating roof

systems into their designs. Slopes as shallow as 1:20 are possible ensuring sufficient drainage of

water and good long term performance of roof panels.

These profile steel sheets are usually categorized into two types depending upon the type of fixing

arrangement followed. These two types are known as Through Fastened and second one is Standing

Seam.

Installation of this type of roofing & cladding system can provide 30 years or more of trouble-free

service in most environments.

Insulations

These buildings can be properly insulated by providing fibrous insulation slabs/rolls of non-combustible

Rockwool, Aluminum foil laminated, placed over a metal mesh bed created between the purlins, and

then the roofing steel sheet fixed over it. The siding walls can also be insulated by providing a double

skin profile steel sheet wall cladding having Rockwool Insulation slab sandwiched in between and held

in position with the help of 'Z' spacers in between the two profile steel sheets. In similar pattern a

double skin insulated roofing system can also be erected.

Sandwich Panels

Another alternative is to provide pre-fabricated insulated panels, which comprises two single skin

panels (plain steel sheets zincalume color coated) with polyurethane foam insulation in between.

These panels are intended for use as thermally efficient roof and wall claddings for buildings e.g., in

high altitude areas and cold storages. In addition to the above sandwich panels also find extensive use

in residential as well as non-residential buildings. The panels provide sufficient insulation and noise

reduction properties. Nowadays large cold storage units (Potato, Onion, vegetables, processed foods

etc.) are also made with this pre-engineered building technique.

Crane systems

These pre–engineered buildings can be equipped with Overhead EOT cranes, Semi-gantry cranes, wall

mounted cranes, Mono rails and under slung cranes for various material and equipment handling

operations inside. These buildings are being designed for crane capacities ranging from 1MT to 250MT.

The crane runway beams (Gantry Girders) are simply supported built-up sections with/without cap

channels and with maintenance platforms and ladders. Catwalks for crane maintenance are usually

mounted alongside the crane beams, suspended under rigid frame rafters or elevated above the top of

the building roof. Cranes at various levels can also be provided. PEB vendors gene rally do not keep

the supply of rail and Crane Bridge with crane in their scope.

Mezzanine systems

Standard mezzanine structure consists of built-up beams that support built-up, hot-rolled or cold-

formed mezzanine joists which in-turn support a metal deck. A concrete slab is cast on the metal deck

as a finished surface. Steel checkered plates may also be used as top surface. These mezzanines are

used for office space, storage or equipment supports in industries. For commercial buildings and

highrise structures several types of light weight panel boards are available as horizontal surface.

Bracing system

Longitudinal cross bracing, used to provide lateral stability to the structure against wind, seismic or

other forces, comprises of rods, pipes, angles or cables with an eye bolt and an adjusting nut at both

ends, located near the outer flange of columns or rafters and attached at the web of the rigid frame.

Paints and finishes

Any desired finish can be achieved as per the architect/client recommendations . Various choices are

synthetic enamel or epoxy based paints, depending upon the environment inside and outside the

building.

Accessories, Attachments etc.

As per the functional and architectural requirements, accessories are supplied in ready to fit condition.

Ventilation and lighting systems should be properly designed in consultation with an expert.

High Strength Materials

The standard mild steel used in civil engineering construction have nominal yield stress values of

approximately 250MPa but the PEB industry is using high tensile hot rolled steel plates and coils of

345MPa. Recent revision of IS2062:2006 has incorporated these high tensile grades of steel for

structural uses and there are a good number of manufacturers like TATA, SAIL, etc. who are

manufacturing these in India. The new materials like Fe540B gives yield stress as large as 410MPa in

plate thickness lower than 20mm. the galvalume or zincalume roofing and wall sheets have strengths

in the range of 550MPa. Steel became more popular in design and construction of larger structures as

well structures with unusual geometry due to its large strength to weight ratio, viability of economical

fabrication, and ease of erection.

A typical sample of material specs for a PEB project, as defined and freezed in advance is enclosed for

ready reference. This indicates that the client is assured of the quality of material that is being

supplied.

The design Process & Principles

Pre-engineering of metal buildings can be optimized to meet specific design criteria. Largely Indian

and American practice of design is followed by most of the consultants and PEB vendors in India these

days. A brief of design codes used in each of these is attached herewith:

PEB Design Process in Brief

The Load calculations are done as in the case of a regular frame. Normally, the critical case governing

the designs would be (DL+WL) or (DL+LL) conditions as the PEB slopes are minor (like 1 in 10). The

support conditions are normally hinged, but it is some times beneficial, on a selective basis to use a

fixed condition giving a gussetted base plate and Anchor bolt combination. In Hinged base condition,

the section is normally tapered down and provided with a Bolted connection to the base. All the other

Joints would be normally designed as rigid joints and steel connections are moment connections,

transferring the axial, moment and shear values between the sections connected. In the Wind load

calculations, the design wind pressures should be arrived at after a careful analysis and combinations

of internal and external pressure coefficients or force coefficients, referring to IS-875 pt.3 latest

version. Proper load combinations with Wind, Earthquake and Crane loads should be investigated.

Any standard structural analysis and design software can be employed for PEB designs, like STAAD

etc. However, couple of good dedicated software is also available for PEB like MBS, Precision Plus etc.

Since detailing and connectivity of various components is much more important, owing to CKD nature,

it is good to use a high end detailing software that also has a BIM capability, like TEKLA Structures,

which provides a complete integration of complete analysis, design, detailing, Bill of material

preparation and production/dispatch/erection planning.

Usually, Checking the Combination Stresses and comparing with the limiting values (in LSD or WSD) is

done using interactive software, which calculates the Exploitation efficiency of the section, i.e., if the

Actual Stress/permitted stress is 0.95, it means that the section is exploited for 95% of its strength.

For this, the total weight of the frame is calculated. A no. of trails are done such that sections are

designed with Variables like Flange thk, Web thk, Flange Width, Web Depth, so that the Entire frame

becomes theoretically safe, and is of minimum wt! Checking for defections is the next step. Many

times sections need to be revised to hold the theoretical maximum deflections within the permissible

ones. Some Vendors exploit 90% of the section, leaving 10% for probable lapses in manufacturing,

transporting, assembling & erection. But the competition has made (forced) people believe that there

are no lapses anywhere! The Next important step is to design the welds between the flanges and

Webs. Here too, Efficiency of the weld plays an important part. Hence, PEB manufacturer will avoid

any weld at the site, because a 4.5 mm weld at the shop may be better than 6 or 8 mm weld at the

site.

Next step is to design the Field joints (Where the parts are assembled at the site). The resultant forces

are known at the joints; design a bolted connection, preferably perpendicular to the plane of frame, to

exploit tensile capacity of bolts for BMs rather than the shear capacities. Hence, Number of bolts

required for the connection will reduce. These joints are also placed at Optimum locations! That is the

advantage of pre engineering.

The secondary members like Purlins and Girts are designed as per codes for thin Cold Formed

Sections, with or without lip. One can use many span reducing and Lateral supporting techniques like

sag rods and knee bracings, tie rods to optimize the sections.

Some issues in PEB Design trend in India

While the Analysis of any Structure would be universal, designs need to be done as per the lo cal/

regional codes. Otherwise why different countries have different codes of Practice? For example, if a

PEB is built in India, The load calculations need to be as per the latest IS 875, the designs need to be

as per IS800 for main frame members, as per IS 801 for thin rolled secondary members (Z and C

purlins and Girts). If a country does not have a code, the building may follow the UBC or the code of a

country near by IF suitable.

To make the superstructure most economical and very competitive, most o f the PEB vendors select

the codes as per THEIR requirement. For example, for a structure built in India, they might calculate

the loads as per IS 875, but do the design as per AISC or AISI, MBMA and use welds as per AWS. If

they feel that the Steel Section is lighter as per one code, they will adopt THAT clause of the code and

select another clause of another code of another country for the design of some other part of the

same building. Some PEB vendors select some clauses of previous versions of the Code and other

clauses of the Latest Versions! This style is not the same every time. PEB Design teams are on

constant research in the Selection of Codal provisions of various countries and are on trials with

different clauses.

The evolution of a Code of Practice is based on the Weather & other climatic conditions, Material, Local

Practices, Skill levels at manufacturing, Transporting, Assembling, erecting, finishing and maintaining.

Hence it is ridiculous to use Indian Steel plate of any yield stress, Cut and manufactured in India,

Loaded & transported in Indian Style, Unloaded and stacked in Indian Style, Assembled & erected by

Indian (skilled) Labour, Finished by Indian Painters using Indian paints, Maintained by Indian Client in

an Indian Town or village BUT DESIGNED USING AMERICAN CODE..! Several clients, structural

engineers, Architects and consultants in India have a myth that American Codes are Better than

Indian!

This way of varied design is legally not valid. If the loads and Codes are not specified by the buyer, it

should be on the PEB supplier to use the Local/ Regional Codes of practice.

To conclude, Clients, Architects and Engineers in India, Beware! The Pre Engineered Buildings are not

a New Concept. But the Jumping-Code-Practice is the NEW Concept and STYLE. If you are not sure of

the Codes, DO NOT SIGN a Purchase order just copying the Specifications given by the PEB Vendor.

Just mention somewhere that the Latest Revisions of Indian Standard Codes should be followed.

Luckily, India has all the codes available for the design of all the Parts of a PEB structure.

High Engineering Production/Erection Process

The PEB production process primarily consists of FOUR major parallel processing lines, as under:

1. Built-up members for Primary frame

2. Cold forming for Secondary framing

3. Profiling for Roof and Wall sheeting

4. Accessories & Bracings like Gutters, down take pipes, ridge Vents, Skylights, clips etc.

The flow chart in image explains the parallel processing and then after final inspection, ready for

shipment in CKD conditions.

The production & shipment of these components for a PEB structure uses following processes:

1. Plate cutting using Shear/Plasma/Multi-torch through nesting software for optimized use of

plate area.

2. H-beam welding on automatic welding machines using SAW or MIG welding process

3. Fabrication for fitments like end plates, stiffeners and connections cleats.

4. Cleaning the surface for painting

5. Slitting HR coils for cold forming operations to make Z and C sections with punching

6. Cutting and threading sag rods and bracing rods

7. Fabrication of Diagonal bracing angles or pipes

8. Profiling the Galvalume/Zincalume sheets for roofing and wall cladding

9. Manufacturing Gutters, down take pipes in press bend

10. Procuring and assigning required matching fasteners for connections

11. Organizing some bought out accessories

12. Quality control tests & inspection; and matching with project wise Bill of Quantities as given by

the engineering department.

13. Dispatching to project sites as per sequence of erection

Erection

Steel framing members are delivered at site in pre-cut sizes, which eliminates cutting and welding at

site. Being lighter in weight, the small members can be very easily assembled, bolted and raised with

the help of cranes. This system allows very fast construction and reduces wastage and labour

requirement. These buildings can then be provided with roof decking and wall cladding with metal

profile sheets and proper insulation. The framing are so designed that electrical and plumbing services

are part of it and can be very easily concealed.

However, the erection process is highly technical and needs skilled and trained manpower to handle

heavy construction equipments. Proper training of erection engineers for understanding of drawings

and execution of work is necessary. A qualified and experienced work agency should be employed for

erection work.

Grey Areas: Points of Concern: What Glitters is not always GOLD…????

The evolution of the application of steel in civil engineering practice gives rise to many issues from the

point of view of engineering design, research and development of steel structures.

Issues of Concern

Fire protection

Although great advances have been made in lighter and more economical fire protection

systems but fire protection remains an issue of greater concern for steel structures than

compared to concrete or other construction materials. The smaller members and thermal mass

associated with steel structures makes it more vulnerable. The memories of collapse of world

trade centre towers in USA due to fire caused by burning of aviation fuel and sudden rise of

temperature leading to complete destruction of structure might not have faded away. Fire

protection adds up to larger part of structural cost. It would be a challenge to engineers

toward reducing these costs, while assuring adequate resistance to elevated temperatures

expected during a fire.

Buckling

Buckling and stability become more critical in Steel structures due to smaller members and

large stress levels.

Micro Cracks

The increasing yield stress, operating stress levels, emphasis on plastic and ultimate capacity,

and use of welded construction have resulted in increased frequency of initiation of micro

cracks and cause of fracture in bridges and industrial structures. Further development of Micro

Cracks and crack growth become a major concern in areas of seismically vulnerable areas.

Corrosion

Steel has great tendency to corrode when exposed to the environment, which leads to

deterioration, increased maintenance costs, and increased reconstruction costs. Although

Galvanization, paint, and coatings may provide protection against corrosion, yet they increase

the overall fabrication costs of the steel structure appreciably. In hot and humid regions and

industrially polluted severe environments problem is more pronounced. Therefore, engineers

have to continually seek economically viable solutions to aim at reducing these costs.

Welding

Presently welded constructions are more commonly used, for these provide stiffer, stronger

structures with reduced building weight. Increased steel yield strength requires new innovative

welding methods, because high strength steels pose more difficulty to weld without affecting

adversely the ductility and performance of the structural system. Recently the use of fully

automatic and semi-automatic submerged arc welding results in increase in welding speed

apart from the good quality. The elimination of any fumes, smoke or any visible arc column

gives an ease of operation and efficiency; better quality & thus encourages its application in

welding industry.

Ductility from seismic considerations

Seismic design is today a must requirement for almost all civil engineering structures.

Although steel is an ideally more suited material from point of view of seismic design because

of its property inherent material strength, stiffness, and ductility. Weldability may affect the

seismic performance and it follows that new methods to improve inelastic seismic performance

of steel structures need to be investigated.

Meliorations

Critics point to poor aesthetics with a typical 'industrial' or 'warehouse' look; minimal flexibility

regarding location, shape and size of structural members; the need to utilise off the shelf building

shapes and sizes in order to realise cost savings; and a lighter structure which does not achieve the

longevity of more conventional structural systems.

"The most basic prerequisite of PEB is 'single sourcing' of the entire building. Any slight deviation from

this can deprive the customers of the real advantages. Also, as steel is prone to corrosion, it would

require various protective coatings which may sometimes make PEB unfeasible economically."

Maintenance

In PEB the maintenance area is the steel roofing & cladding. Installed roofing must be inspe cted at

least once a year. Any exposed metal that can rust or has rusted should be painted. Leaves, branches,

and trash should be removed from gutters, at ridge caps and in corners. Also watch out for discharge

from industrial stacks, and particulate matter and high sulphur exhaust from space heaters which

could get piled up.

The Future Bright Towards the Economic growth

Steel is a preferred material for construction, due to its various advantages like quality, aesthetics,

economy and environmental conditions. This concept can have lot of scope in India, which can actually

fill up the critical shortage of housing, educational and health care institutions, airports, railway

stations, industrial buildings & cold storages etc.

Pre-engineered Metal building concept forms a unique position in the construction industry in view of

their being ideally suited to the needs of modern Engineering Industry. It would be the only solution

for large industrial enclosures having thermal and acoustical features. The major advantage of metal

building is the high speed of design and construction for buildings of various categories.

The present construction methodology for buildings calls for the best aesthetic look, high quality & fast

construction, cost effective & innovative touch. One has to think for alternative construction system

like pre-engineered steel buildings. India has an installed steel capacity of 35 to 40 million ton &

apparent steel consumption is around 27 to 30 million ton. In pre-engineered building concept the

complete designing is done at the factory and the building components are brought to the site in

knock down condition. These components are then fixed / jointed at the site and raised with the help

of cranes.

PEB concept has been very successful and well established in North America, Australia and is presently

expanding in U.K and European countries. PEB construction is 30 to 40% faster than masonry

construction. PEB buildings provide good insulation effect and would be highly suitable for a tropica l

country like India. PEB is ideal for construction in remote & hilly areas.

They are the only answer to the backlog of 33 million houses required in India alone, provided that the

system offers quality, economy, and speed together. The building system is developed considering all

aspects of building requirements and simultaneously offers technological advancement to all sections

of society.

Recent Innovations

High performance steels (HPS)

Fire-resistant steels:

Steels with increased ductility

Corrosion resistant steels

Concrete filled steel tubes (CFT)

Future Trends

In this era of competition it is increasingly important to build more economical structures, which

provide good integrated system performance. Steel is basically better suited for bigger, taller, and

longer span and geometrically complex structures, as a result, steel is likely to be predominantly used

for many years into the future. Increased economy in civil engineering construction is achievable

through higher strength steel, composite form of construction and improved materials therefore

engineering community is more akin to use steel structural systems in the future and it is felt that this

trend will continue. Engineers will need to develop suitable Codes and specifications for the purpose to

meet the requirements of future generations. There is increased invest more for research and

development for innovative material and construction methodologies.

One has to use the PEB products, with a word of caution, and frame the contract provisions

accordingly. We are fairly close to a day when steel buildings should be the rule, rather than being the

exception, if we work together to give the Client, best value for his money.

PEB: A Boon for Building Industry

The pre-engineered building technology, which entered the Indian construction arena during the late

nineties has over a period of time gained widespread acceptance among the end users and is steadily

making inroads in the construction and infrastructure projects across the country. This is largely due

to the fact that PEB-based construction technique is offering the most innovative, hi-tech, and quicker

methods of construction ensuring efficient, cost effectiveness and speedy completion of projects,

which is perhaps the pre-requisite for the construction sector to meet tight construction schedules and

demanding deadlines.

Drawing overwhelming response from construction and infrastructure builders, due to heightened

construction activities currently going on across the country, the global players in the PEB industry

have not just set up their shops but also launched multi-prong brand building initiatives by holding

technical seminars, exhibitions and events displaying their products to popularize the benefits of PEB

brands. In the process, they have been able to create awareness informing people that under the PEB

systems buildings are built keeping the, eco-friendly environs, aesthetic value, designing, durability,

energy efficiency, cost effectiveness and speedy completion of the construction projects in mind.

With increased emphasis on the on-going green buildings ensuring sustainable construction, the PEB

structures are created with a high proportion of recycled content making them lighter by about 30%

than the conventional steel buildings. They contain higher degree of fire and dust resistant and are

maintenance free. As a result today the PEB system is the most preferred choice among the

architects, builders, developers and industrialists. The experts in the field are unanimous in their view

that the PEB industry in India is currently heading to achieve growth trajectory of about 35% per

annum.

To know more about the PEB systems, its evolutions, benefits, future prospects and an unassailable

edge it enjoys over the conventional systems of construction, MGS Architecture has interacted with

cross sections of experts engaged in the field and has also elicited views of the captains of the PEB

industry for the benefits of its readers.

Kirby Building Systems India Ltd.

Sharing his viewpoint with the MGS Architecture, Mr. D Raju - CEO, Kirby Building Systems, explained

that while selecting the right type of building material for the project in hand, the pre -engineered steel

building system is a preferred choice because of its cost effectiveness and its potential to provide a

quicker solution to those setting up industrial and commercial facilities. The economy comes from the

fact that pre-engineered steel building mechanism comprising primary, secondary and cladding

components are designed as a system. The use of high strength steel & possibility of manufacturing

sections with varying/tapered section sizes to match bending moment diagrams allows economizing

the use of steel to achieve optimum weights.

Elaborating on the Kirby's presence in the country, he revealed, the company is a part of the Alghanim

Group of Industries, Kuwait based multinational business conglomerate with diversified businesses.

Kirby Building Systems is one of the world's largest producers of quality steel buildings and has been

operational since 1976. The company recognized the need of customers and the potential in the Indian

market and was the first to set up a mega manufacturing facility in India near Hyderabad in 1999.

Since then the company has aggressively promoted the use of PEB concept in India.

The opening up of the Indian economy in the early nineties resulted in an influx of multinational

companies into India and the use of this concept spread widely in the country with Kirby being the

torch bearer. Today, at 200,000 MT capacity per annum and presence across different industry

segments through steel buildings, Kirby is the market leader with more than 8 million sqm of Pre -

engineered Steel Buildings in India and its ability to handle any size of project remains unmatched.

Kirby's product portfolio includes PEB, Sandwich Panels, Industrial Racks, etc. Sharing Kirby's

dominance in the Indian market, Mr. Raju said that Kirby enjoys a market share of over 40% and

maintained its dominance in the PEB market. Kirby India has executed over 10,000 buildings till now

from a simple Warehouse building to the most complex Shipyard building and has a customer base of

over 3,500.

Kirby has the privilege of partnering most of the leading corporates across different industry verticals

by setting up their facilities. To name a few, Kirby has been associated with companies such as Nokia,

Skoda, Tata, Reliance, UNICEF, Swaraj Mazda, BMW, Renault-Nissan, Suzlon Group, Birla Tyres,

Apollo Tyres, MRF Tyres, Bridgestone, Pipavav Shipyard, Jindal Group, Mahindra Group, JSW -Toshiba,

etc.

Mr Raju said that the company's Standing Seam Roofing System (KSS-600) is tested and approved by

FM Global, USA and has double lock standing seam ends which provides 100% leak proof buildings

with faster installation. In addition to these, implementation of SAP in 2008 further strengthened

Kirby’s internal processes and operations which are well integrated thereby ensuring better customer

service.

He said adding that our company has always invested in the awareness programs and brand building

exercise through participation in exhibitions, seminars and conferences and through advertisements.

Today, Kirby has become a generic name in the Pre-engineered Steel Building market in India and has

maintained its market leadership because of its state-of-the-art manufacturing and engineering

facilities, strong execution team and a network of over 100 certified builders. Kirby India has 25 sales

offices across the country equipped with experienced resources and is always planning to expand its

geographical reach to smaller industrial towns to be near to its customers and maintain its leading

position in the Indian PEB market.

Pebs Pennar

Dwelling in details on the current scenario, its growth potentials and future prospects, Executive

Director, Mr. P.V.Rao., Pebs Pennar explained that the concept of pre-engineered buildings has been

catching up fast in India since 2000 and its market has been growing at the rate of 20 to 30% every

year since then. Though there has been some slowdown in developed world due to recent global

recession during which the per capita consumption of steel has considerably been reduced in countries

like USA, Japan, Europe, Russia and UK. India remains relatively resilient to the global crises and

consumption of steel in India is expected to grow between 9 to 11% in the current fiscal.

Elaborating on the advantages of the PEB over the conventional system, he said that the Pre -

engineered Buildings are economical, faster to construct, aesthetically appealing, durable, re -

locatable, earthquake resistant, easy maintenance, factory controlled quality with wider spans

network. In this connection, we are conducting seminars at various important cities and inviting

consultants, architects and customers. We are explaining the benefits of PEBs in these events. Also we

are participating in exhibitions and trade events like Roof India, Metal Buildings Systems etc. In most

of the projects, the customers are guided by the consultants and architects for the complete turnkey

solution. To face the tough competition in the PEB market we have a qualified talented and

experienced team in our engineering, sales, production and erection department. The team has been

chosen to outperform in all quarters with their unmatched expertise of world repute, capability to

understand complex structures and in-depth knowledge of designing pre-engineered buildings.

Our state-of-the-art manufacturing facility at Hyderabad has been equipped with high precision CNC

machines to fabricate and supply quality-replete steel buildings. We offer Double lock standing seam

roof sheeting in technical collaboration with NCI, USA, which is 100% leak-proof and a proven product

in USA for the past 50 years. We have a dedicated project management department which takes care

of erection and after sales service. To cater to the aspirations of the customers we are providing multi-

storied buildings for both commercial and residential segments and currently using Autocad, Stadpro,

MBS & Visomax software’s for designing our Pre-engineered buildings projects.

PhenixVP

During his interaction with MGS Architecture, the Joint Managing Director and Chief Executive Officer

(CEO) PhenixVP, Dr V. R. Rajan, explained that over the past 10 years the focus of the world has

shifted on India and China, the emerging super powers of the world. With a GDP growth rate of

around 8%, India is offering a lot of benefits to companies by setting up SEZ's across the country.

This growth rate is expected to be consistent for the next 30 years and gives reasons to the

multinationals to set up shops in India. Every sector, whether be it manufacturing, transport, energy,

infrastructure or commodity is growing at a greater pace and all these sectors require industrial hi-

tech buildings to run business operations. On this score, PEB enjoys an edge over conventional

methods of construction because of its advantages of shorter construction cycle and aesthetic appeal.

Also, in the current scenario Pre-engineered building occupies only 10% to 15% of the total Industrial

construction currently going-on in the country, as compared to 95% in countries of the western world.

In India, we expect the growth rate of 20% to 25% on year on year basis in the Pre -engineered

building space.

Elaborating on the advantages of the PEB system over conventional methods of building, he gave the

detailed analytical explanation in the Table 1.

Explaining the awareness level among the industrial building customers, he said that the builders have

accepted that optimized technology and flexibility which is being offered by PEB is unmatched as

compared to conventional buildings. They have now started realizing that the Pre-engineered buildings

have much more to offer than just the industrial building complex. In totality, the quality of steel used

in PEB is superior as per the standards laid down by the MBMA. This helps out to optimize the design

considering the dynamic loads, seismic loads, and wind speed to provide a better product at a lower

price as compared to conventional buildings and they can be designed as per any IS standards. In this

connection, we undertake programs to increase awareness about PEB by organizing technical

seminars, exhibitions and advertisements. Also, our marketing team tries to educate the new clients

and consultants and helps them reduce the cost. Currently, we are providing multi–storey buildings up

to G+5 floors both for residential and commercial purposes.

In order to maintain edge in the face of tough competition, we offer tech- nical advantages in design,

fabrication, installation and top class after sales service to our customers by adhering to the guidelines

given in Table 2.

Ensuring quality and standards of our product, we use software of globally repute players like VP

Command and StadPro in our designing and planning mechanism. We have a technical tie-up with

Varco Pruden, which is the top company in PEB in US, whereas Strata Pro is used especially for more

complex buildings. We maintain rigorous quality standards through in-house quality inspection as per

the project requirements. We are certified under ISO 9000/ISO 18000/FM Global/MES and also a

member of Indian Green Building Council.

Zeppelin Mobile Systems India Ltd

The Deputy General Manager, Sales, Zeppelin, Mr. Shiv Kumar Gupta, in his conversations with MGS

Architecture, reiterated that PEBs have tremendous scope and brighter future prospects as a solution

to industrial and factory buildings in India. We at Zeppelin intend to be recognized as a leader in the

PEB. This would be accomplished through pledge ensuring product perfection, engineering excellence

and the best customer services in the industry. The applications of PEBs will be driven by multiple

factors including spreading awareness of advantages of PEB over conventional buildings, synchronizing

with the customer aspirations, requirements and suitability to build optimum capacity, efficient & cost

effective steel factories made of PUF panels for quicker return-on-investment apart from designing and

fabricating safe and technologically advanced PEB buildings. Likewise its usages will also be

augmented by offering customers versatility in design & fabrication to meet their exact building &

facility requirements, besides offering better after sales services to the utter satisfaction of our

customers. He explained the pluses of PEBs over the conventional methods of building in the Table 3.

Lamenting that the customer base today doesn’t have sufficient awareness about PEB’s as the

optimum building technology for their applications, in this connection our company is focused on

building this market and will make all out efforts to increase the awareness leading to the adoption of

PEBs on a larger scale.

Maintaining competitive edge he explained that we are a pole apart from our nearest competitors as

we offer the latest design codes (AISC 2005) and adopted Indian standards IS801 and 811, besides

applying fully automatic welding systems. Our company makes high capacity delivery with a minimum

time span of three to four weeks with abysmally low construction cost by making available free Shot

blast for all types of jobs. In addition, we are using galvanized or painted purlins with large and clear

span apart from providing adequate option for future expansions. Offering structure with low

maintenance cost, faster designing approvals of fabrication drawings and quicker installation at site

are among the other factors keeping us ahead of our nearest competitors.

Our company is currently using STAADPRO software based on design and analysis of PEB, as this

software has been approved by various government departments and also by MBMA. This can easily

calculate the live load, dead load, seismic load and wind load. As of now our company is providing

Mezzanine up to three to four meters besides providing the PEBs up to 28 to 35 meters height.

The Fast-Food of Construction Industry

Today, the Indian construction industry is in full bloom and so is the real estate sector. With the

demand for both residential and commercial segments increasing, there is a need to get the projects

completed on time so as to minimize extra costs. Also, with a major emphasis being laid on the

infrastructure as well as the current boom in the commercial buildings, developers are now looking

towards other options so as to meet the deadlines and curtail the expenditure.

This is where the prefabricated or the prefab industry comes in. To name it as the 'fast-food'of

construction industry would not be wrong as this has now come across as the most viable option for

instant completion of projects for various endeavors.

Why Prefab?

The usual construction methods are now giving way to more specialized and efficient materials and

techniques for construction. Constant innovation has helped the sector to come out with new

techniques that help in quick and easy realization of projects. Prefabricated construction is not new to

India, but it has suddenly gained importance seeing the demand for housing and infrastructure rising.

With the conventional methods of construction using brick and mortar time consuming and not

efficient, prefab construction proves to be a better and efficient alternative.

Prefabricated structures are useful for sites where normal construction is not suitable like hilly regions,

flyover sites, and even commercial buildings. Builders initially needed a lot of convincing to accept the

benefits which cannot be availed on the actual construction sites. But, seeing the advantages of prefab

construction, builders are now clearly going in for it as it requires less time and is more well-

organized.

In India, prefab construction till now had been restricted to constructing small units like project site

offices, cold storages, exhibition halls, portable cabins, kiosks, workshops and warehouses. But now

with the country witnessing an infrastructure boom, even flyover construction and the Metro are

applying the prefab construction techniques for the simple reason that normal construction methods

cannot be used due to safety issues at these sites and work can be finished faster and with ease.

Though prefab construction is popular with commercial buildings and other infrastructure projects, the

residential buildings however do not utilize this technique. The main reason behind this is the cost

which usually spirals if residential blocks are built by this technique. Since the prefab company would

have to make a customized mould according to the specifications, it would mean starting from scratch

and thus increasing the costs as compared to conventional building. Also, space constraints and the

trouble of following up with the prefab company usually deter people from opting for this type pf

construction. Since the transportation costs of prefab structures have to be borne by the owners, the

cost increases as compared to the conventional construction type, which is also a major deterrent.

Prefab Materials

The prefab materials basically include fibre cement corrugated and plain sheets, auto calved aerated

concrete blocks, access flooring systems, calcium silicate insulation products, jointing material for

automobile gaskets, and plant and machinery for fibre cement products.

The very need to go the prefab way is because of less time spent on building, less intrusion made on

the surroundings, and less invasion of the environment at the construction sites. P refab construction

also ensures quality control because of assembling the units in the factory, thus shuttering and

scaffolding is eliminated; time wasted due to bad weather conditions is minimized; the molds can be

used several times; and it also allows greater flexibility in relocating and redesigning. Easy availability

of materials and skills are also important factors for the greater use of prefab construction.

Issues

In India, the prevalent use of prefabricated structures has just increased due to the sudden awareness

amongst builders for cost-effective and speedy construction. But there are certain issues which need

to be dealt with while employing this technique. The structures need to be carefully handled especially

concrete, steel or glass panels. A lot of care needs to be taken for the strength and corrosion-

resistance of the joining of prefabricated sections to avoid failure of the joints. Because of the huge

transportation costs of large volumes of structures since they have to be more cautiously packed.

Large prefabricated sections require heavy-duty cranes and precision measurement and handling to

place them in position. In India, there are just a few companies that supply equipment for

transportation like Kirby Building Systems India and Minaean Habitat India amongst them, thus

making way for many players to enter.

Construction labor is easy to find but labor for prefab construction is still an issue. Since, this requires

a lot of technical knowhow, it is a necessity to get workers who have had experience in prefab

construction or are aware of the handling of structures and materials in order to avoid undue loss.

Prefab construction is the next best thing for India. With not only the doors and windows but also the

entire structures being prefabricated, this opens a whole new world of opportunities for builders and

architects, to give the end-users superior quality in shorter durations. Offsite construction has given

the builders, a chance to contribute in making the environment clean and green.

In structural engineering, a pre-engineered building (PEB) is designed by a PEB supplier or PEB

manufacturer, to be fabricated using best suited inventory of raw materials available from all sources and

manufacturing methods that can efficiently satisfy a wide range of structural and aesthetic design

requirements. Within some geographic industry sectors these buildings are also called Pre-Engineered

Metal Buildings (PEMB) or, as is becoming increasingly common due to the reduced amount of pre-

engineering involved in custom computer-aided designs, simply Engineered Metal Buildings (EMB).

Historically, the primary framing structure of a pre-engineered building is an assembly of I-shaped

members, often referred as I-beams. In pre-engineered buildings, the I beams used are usually formed by

welding together steel plates to form the I section. The I beams are then field-assembled (e.g. bolted

connections) to form the entire frame of the pre-engineered building. Some manufacturers taper the

framing members (varying in web depth) according to the local loading effects. Larger plate dimensions

are used in areas of higher load effects.

Other forms of primary framing can include trusses, mill sections rather than three-plate welded,

castellated beams, etc. The choice of economic form can vary depending on factors such as local

capabilities (e.g. manufacturing, transportation, construction) and variations in material vs. labour costs.

Typically, primary frames are 2D type frames (i.e. may be analyzed using two-dimensional techniques).

Advances in computer-aided design technology, materials and manufacturing capabilit ies have assisted a

growth in alternate forms of pre-engineered building such as the tension fabric building and more

sophisticated analysis (e.g. three-dimensional) as is required by some building codes. [1]

Cold formed Z- and C-shaped members may be used as secondary structural elements to fasten and

support the external cladding.

Roll-formed profiled steel sheet, wood, tensioned fabric, precast concrete, masonry block, glass

curtainwall or other materials may be used for the external cladding of the building.

In order to accurately design a pre-engineered building, engineers consider the clear span between

bearing points, bay spacing, roof slope, live loads, dead loads, collateral loads, wind uplift, deflection

criteria, internal crane system and maximum practical size and weight of fabricated members. Historically,

pre-engineered building manufacturers have developed pre-calculated tables for different structural

elements in order to allow designers to select the most efficient I beams size for their projects. However,

the table selection procedures are becoming rare with the evolution in computer-aided custom designs.

While pre-engineered buildings can be adapted to suit a wide variety of structural applications, the

greatest economy will be realized when utilising standard details. An efficiently designed pre-engineered

building can be lighter than the conventional steel buildings by up to 30%. Lighter weight equates to less

steel and a potential price savings in structural framework.

Project professionals and manufacturer-designed buildings

The project architect, sometimes called the Architect of Record, is typically responsible for aspects such

as aesthetic, dimensional, occupant comfort and fire safety. When a pre-engineered building is selected

for a project, the architect accepts conditions inherent in the manufacturer's product offerings for aspects

such as materials, colours, structural form, dimensional modularity, etc. Despite the existence of the

manufacturer's standard assembly details, the architect remains responsible to ensure that the

manufacturer's product and assembly is consistent with the building code requirements (e.g. continuity of

air/vapour retarders, insulation, rain screen; size and location of exits; fire rated assemblies) and

occupant/owner expectations.

Many jurisdictions recognize the distinction between the project engineer, sometimes called the Engineer

of Record, and the manufacturer's employee or subcontract engineer, sometimes called a specialty

engineer. The principal differences between these two entities on a project are the limits of commercial

obligation, professional responsibility and liability.

The structural Engineer of Record is responsible to specify the design parameters for the project (e.g.

materials, loads, design standards, service limits) and to ensure that the element and assembly designs

by others are consistent in the global context of the finished building.

The specialty engineer is responsible to design only those elements which the manufacturer is

commercially obligated to supply (e.g. by contract) and to communicate the assembly procedures, design

assumptions and responses, to the extent that the design relies on or affects work by others, to the

Engineer of Record – usually described in the manufacturer's erection drawings and assembly manuals.

The manufacturer produces an engineered product but does not typically provide engineering services to

the project.

In the context described, the Architect and Engineer of Record are the designers of the building and bear

ultimate responsibility for the performance of the completed work. A buyer should be aware of the project

professional distinctions when developing the project plan.