PRESENTED BY:

(13-arb-553) Yasir Mazhar

(13-arb-559) Areeb Khan
(13-arb-560) Prakhar Varshney
(13-arb-564) Syed Saud Ali
(13-arb-573) Aayush Agarwal
(13-arb-576) Tabish Suhail
Portal Frames
• PORTAL FRAME IS A RIGID STRUCTURAL FRAME CONSISTING ESSENTIALLY OF TWO
UPRIGHTS CONNECTED AT THE TOP BY A THIRD MEMBER.
• PORTAL FRAMES ARE SINGLE STOREY, SINGLE( OR MULTI-BAY) FRAMES WITH PITCHED
OR FLAT ROOF. FABRICATED FROM UNIVERSAL BEAMS, IT IS AN IDEAL STRUCTURAL
SOLUTION IN MANY CIRCUMSTANCES, REGARDING ITS ECONOMIC AND STRUCTURAL
EFFICIENCY.
Portal Frames
• Made in a variety of shapes and sizes.
• Made from steel, but can also be made from concrete or timber.
• The portal structure is designed in such a way that it has no intermediate columns, as a
result large open areas can easily be created within the structure.

Portal Frames are generally used for single storey construction which require a large
unobstructed floor space i.e. Factories, Shopping Centres, Warehouses.
Advantages & Disadvantages
Advantages
• Speed and ease of erection.
• Building can be quickly closed in and made water tight.
• Steel members prefabricated in a workshop and not affected by
weather.
• Site works such as drainage, roads etc. can be carried out until
framework is ready for erection.
• No weather hold up during erecting the framework.
• Connected together in factories by welding and site connections
should be bolted.

Disadvantages
• Although steel is incombustible it has a poor resistance to fire
as it bends easily when hot.
• Subject to corrosion.
COMPONENTS OF PORTAL FRAMES
• Primary steelwork consists of columns and rafters, which form portal frames, and bracing.
COMPONENTS OF PORTAL FRAMES

• Secondary steelwork consists

of side rails for walls and
purlins for the roof.

• The secondary steelwork

supports the building envelope.

• The roof and wall cladding

Provides thermal and acoustic
insulation.
TYPES OF PORTAL FRAMES
• PITCHED ROOF SYMMETRIC PORTAL FRAME
GENERALLY FABRICATED FROM I- SECTIONS WITH A
SUBSTANTIAL EAVES HAUNCH SECTION, WHICH MAY BE CUT FROM
A ROLLED SECTION OR FABRICATED FROM PLATE. 25 TO 35 M ARE
THE MOST EFFICIENT SPANS.

• PORTAL FRAME WITH INTERNAL MEZZANINE FLOOR

OFFICE ACCOMMODATION IS OFTEN PROVIDED WITHIN A PORTAL

FRAME STRUCTURE USING A PARTIAL WIDTH MEZZANINE FLOOR.
• CRANE PORTAL FRAME WITH COLUMN BRACKETS
WHERE A TRAVELLING CRANE OF RELATIVELY LOW CAPACITY (UP TO SAY
20 TONNES) IS REQUIRED, BRACKETS CAN BE FIXED TO THE COLUMNS
TO SUPPORT THE CRANE RAILS. USE OF A TIE MEMBER OR RIGID COLUMN
BASES MAY BE NECESSARY TO REDUCE THE EAVES DEFLECTION.
THE SPREAD OF THE FRAME AT CRANE RAIL LEVEL MAY BE OF CRITICAL
IMPORTANCE TO THE FUNCTIONING OF THE CRANE; REQUIREMENTS
SHOULD BE AGREED WITH THE CLIENT AND WITH THE CRANE
MANUFACTURER.

TOP HUNG CRANE PORTAL FRAME MONO RAIL POTAL FRAME

• TIED PORTAL FRAME
IN A TIED PORTAL FRAME THE HORIZONTAL MOVEMENT OF
THE EAVES AND THE BENDING MOMENTS IN THE COLUMNS
AND RAFTERS ARE REDUCED. A TIE MAY BE USEFUL TO LIMIT
SPREAD IN A CRANE-SUPPORTING STRUCTURE.
.

• MONO-PITCH PORTAL FRAME

A MONO PITCH PORTAL FRAME IS USUALLY CHOSEN FOR
SMALL SPANS OR BECAUSE OF ITS PROXIMITY TO
OTHER BUILDINGS. IT IS A SIMPLE VARIATION OF THE
PITCHED ROOF PORTAL FRAME, AND TENDS TO BE USED
FOR SMALLER BUILDINGS (UP TO 15 M SPAN).
.
Wallace Ville, Upper Hutt, Wellington
• PROPPED PORTAL FRAME
WHERE THE SPAN OF A PORTAL FRAME IS LARGE AND THERE
IS NO REQUIREMENT TO PROVIDE A CLEAR SPAN, A PROPPED
PORTAL FRAME CAN BE USED TO REDUCE THE RAFTER SIZE
AND ALSO THE HORIZONTAL SHEAR AT THE FOUNDATIONS.
.

• MANSARD PORTAL FRAME

A MANSARD PORTAL FRAME MAY BE USED WHERE A LARGE
CLEAR HEIGHT AT MID-SPAN IS REQUIRED BUT THE EAVES
HEIGHT OF THE BUILDING HAS TO BE MINIMISED.
• CURVED RAFTER PORTAL FRAME
PORTAL FRAMES MAY BE CONSTRUCTED USING CURVED RAFTERS,
MAINLY FOR ARCHITECTURAL REASONS. BECAUSE OF TRANSPORT
LIMITATIONS RAFTERS LONGER THAN 20 M MAY REQUIRE
SPLICES, WHICH SHOULD BE CAREFULLY DETAILED FOR
ARCHITECTURAL REASONS.

• CELLULAR BEAM PORTAL FRAME

RAFTERS MAY BE FABRICATED FROM CELLULAR BEAMS FOR
AESTHETIC REASONS OR WHEN PROVIDING LONG SPANS.
WHERETRANSPORT LIMITATIONS IMPOSE REQUIREMENT FOR
SPLICES, THEY SHOULD BE CAREFULLY DETAILED, TO PRESERVE
THE ARCHITECTURAL FEATURES.
THE SECTIONS USED CANNOT DEVELOP PLASTIC HINGES AT A
CROSS-SECTION, SO ONLY ELASTIC DESIGN IS USED.
Portal Frames Joints
• Base Joint
THE LEGS OR STANCHIONS OF THE PORTAL FRAME NEED
CONNECTING AT THE BOTTOM TO A FOUNDATION.

HERE WE CAN SEE THE BASE JOINT CONNECTION IN PLACE.

• knee Joint
- Again the knee joint must be strong to support the roof loads and prevent bending.
- Gusset pieces will be used to increase strength, give greater bolt area and prevent deflection under
load.
• Ridge Joint
- Shown here is a ridge joint or apex joint.
- It is Important that this joint is strong hence the use of
wedge shaped pieces called gusset pieces to strengthen and
increase the bolt area.
Roof Covering
• A high percentage of roofs are
covered with composite profile
metals sheets.
• 50 mm of insulation sandwiched
between two thin metal sheets
• Coated steel is lowest in cost but
limited in life
• Profile sheets are quick to erect,
dismantle and repair
External Wall Detail

• Here we see the finish of the external cladding

panels with the lower level facing brickwork
• The blockework behind creates a protective wall
or firewall
Fabrication

• The main (portal) frames are generally fabricated from UKB Sections with a
substantial eaves haunch section, which may be cut from a rolled section or
fabricated from a plate. A typical frame is characterised by :
• A span between 15 and 50m
• Clear height (from the top of the floor to the under side of the haunch) between 5
and 12 m
• A roof pitch between 5” and 10” (6” is commonly adopted)
• A frame spacing between 6 and 8m
• Haunches in the rafters at the eaves and apex
• A stiffness ratio between the column and rafter section of approximately 1.5
• Light gauge purlins and side rails
• Light gauge diagonal ties from some purlins and side rails to restrain the inside
flange of the frame at certain location.
Haunching
• The use of a haunch at the eaves reduces the required depth of rafter.
• Increases the moment resistance of the member where the applied moments are
highest.
• Adds stiffness to the frame.
• Reduces deflections, and
• Facilitates an efficient bolted moment connection.
Two types of haunch:
1. The Eaves Haunch
• Typically cut from the same size rolled section as the rafter, or one slightly larger.
• Welded to the underside of the rafter.
• Length generally 10% of the frame span.

2. The Apex Haunch

• Cut from a rolled section – often from the same size as the rafter,or fabricated
from plate.
• Not usually modelled in the frame analysis and is only used to facilitate a bolted
connection.
Lattice Girders
A lattice girder is a type of girder with a criss-crossed web design, such as in gardening lattices,
between the two edges of the girder. The diagonal lines of steel give support in all directions,
helping to prevent the girder from bending.

San Francisco Oakland Bay Bridge Lattice rebar

There are different types of lattice girders, these are used where plate girders would become
excessively heavy over large spans. They are widely used to support north light trusses with
widely spaced internal columns to cover large areas with the least obstruction.
Uses
• Old Buildings • Often seen on older bridges • Widely used in mining tunnels for
roof support during excavations and
can be erected quickly. Used for
reinforcement when applying
shotcrete, a form of concrete or
mortar pneumatically applied at high
velocity from a hose to construction
supports.

Landeilo Railway bridge over River Towy, Liberty Tunnel, Pittsburgh

Eiffel Tower, Parris Wales
Advantages of Lattice Girders
• Immediate roof support over the excavated section.
• Act as a template assuring a minimum thickness when applying
concrete.
• Become part of the reinforcement in the concrete lining.
• Provide support for spilling, if needed, over the next excavation.
• Work equally well with machine mining or drill and shoot tunneling -
no need for major investment in special equipment.
• Are practical supports for a wide range of ground conditions.
• Can be erected within a few minutes by a small crew without special
handling equipment
Lattice Girder in Slab
The lattice girder system is a semi-precast element floor, where precast concrete panels
are combined with in-situ concrete topping. Lattice girder systems can either be load-
carrying in only one direction, or in two directions.
• Lattice girders are also used as a component to provide structure load bearing support
for floors that will handle heavy loads. They are used to create what are called lattice
girder slabs for high capacities. In curving wall designs, their surfaces can be bonded with
polystyrene void-formers to reduce wall weight loads.
• Lattice Girders are used mainly as reinforcement of prefabricated slabs and beams where
concreting is performed in two stages, offering the advantage of avoiding scaffolding and
formwork needed in traditional construction.

Examples of Lattice Girders used as a reinforcement in slab

Lattice Girders for Bridge Construction
Constructed using a large number of light iron or steel members. The individual
elements are more easily handled by the construction workers.

A simple lattice truss will transform

the applied loads into a thrust, as
the bridge will tend to change length
under load. This is resisted by
pinning the lattice members to the
top and bottom chords, which are
more substantial than the lattice
members, but which may also be
fabricated from relatively small
elements rather than large beams.
Kew Rail Bridge
 Lattice Girders in Tunnel Construction
• A lattice girder can be a component in accommodating large arched openings when using
these void-formers, due to the reduced weight load.
In tunneling operations, a lattice girder is often chosen over a
steel plate girder as it can be completely embedded in a
shotcrete lining that allows for the easier molding of walls
within a tunnel. It can adjust well to differing ground levels
and provide a covering with the shotcrete that keeps out
water. It can handle loads
Well even when the shotcrete
is still curing and soft.

Process of shotcrete being performed

The ability to easily deform the girders to match the walls and
flooring of a tunnel without affecting the load-bearing is why lattice
girders are so trusted in mining projects.
Arched lattice girders for better use
Lattice Girders in Double Walls

• Lattice girders are also

increasingly used in the
production of so called
double walls where they
constitute the bond
between two panels
which are finished on
site with in situ concrete.

Examples of lattice girders in

double walls
Details
Plate girders are built-up flexural members. Flexure means elasticity. In structures elasticity is related to
bending. Hence plate girders are members which are designed to carry flexural loads or bending loads on
primary basis and shear loads on secondary basis
• Plate girders are typically used as long-span floor girders in buildings, as bridge girders, and as crane girders
in industrial structures.
• Commonly term girder refers to a flexural x section made up of a number of elements.
• They are generally considerably deeper than the deepest rolled sections and usually have webs thinner than
rolled sections.
DESIGN OF PLATE GIRDERS
 Modern plate girders are normally fabricated by welding together two flanges and a web plate.
 Any cross-section of a plate girder is normally subjected to a combination of shear force and
bending moment.
 The primary function of the top and bottom flange plates of the girder is to resist the axial
compressive and tensile forces arising from the applied bending moment.
 The primary function of the web plate is to resist the applied shear force.
• Plate girders are at their most impressive in modern bridge construction where main spans of well over
200m are feasible, with corresponding crosssection depths, haunched over the supports, in the range of 5-
10m.
• Because plate girders are fabricated separately, each may be designed individually to resist the applied
actions using proportions that ensure low selfweight and high load resistance.
T Y P ES O F P L AT E G I R D E R

CONNECTION OF FLANGE TO
WELDED PLATE GIRDER WEB BYWELDING
 SPLICING OF PLATE GIRDER BY
BOLTED PLATE GIRDER BOLTING
A P P L I C AT I O N S O F P L AT E G I R D E R
North light is indirect or relected light coming from the north (in the Northern Hemisphere). It
consists of light which comes from the blue sky rather than directly from the sun. It is preferred and
considered ideal by architects.It is also preferred natural light by artists as well. North light has
luminous efficacy 48 lm/W , Colour correlated temperature 6500K and colour rendering index is
equal to 94.
•The north light roof truss has an asymmetrical profile with the south
facing slope at 17 degree or more to horizontal and the north facing slope at
60 degree of inclination.
•The whole of the south slope is covered with profiled sheets and the whole
north facing slope with glass or clear or translucent plastic sheeting.
•most north light roofs are limited to spans of up to 10 m.
TRUSSES USED TO REMOVE DIRECT GLARE FROM THE SUN AND TO MINIMISE HEAT GAIN INSIDE THE BUILDING .
SLANT ROOF COVER WITH PROFILED OR CORUGATED SHEET TO BLOCK SUN AND GLAZING IS PROVIDE VERTICALLY FOR INDIRECT LIGHT TO ENTER THROUGH
THE BUILDING
 B
A C
A) 2 ANGLES JOINED TOGETHER SIZE
120X120X12.
B) PATENT GLAZING BAR USED TO HOLD THE
GLAZING SHEET i.e. glass
D C) GLASS PANEL OR SHEET
F D) EVES FILLER PIECE FOR INSULATION,AND
FILLING VOIDS AND PROVIDING LESS
WEARAND TEAR OF ATTACHED PARTS.
E E) PURLIN ANGLE OF SIZE 90X65X10 USED
G FOR SUPPORT AND HOLDING ANGLE
SECTION AND GLAZING BARS.
F) ANGLE CLEATS OF SIZE 100X100X10 FOR
JOINING PURLIN AND ANGLE TOGETHER.
G) GUTTER FOR FLOW OF RAINWATER..

DETAIL 1
 A
A) RIDGE CAPPING TO SEAL VOID SO THAT
WATER DOES NOT ENTER.
C B B) 125X75X10 AND 80X60X10 ANGLE RAILS
WELD TOGETHER.
D C) 90X65X10 ANGLE PURLIN
F D) 100X75X10 ANGLE BRACKETS USED TO
ATTACH GUSSET PLATE AND RAFTER.
E E) 10mm GUSSET PLATE TO JOIN THE ANGLE
SECTION .
F) 2 RAFTERS JOINED TOGETHER.
G G) 125X75X10 CLEATS..

DETAIL 1
 NORTH LIGHT TRUSS AT HEATHROW AIRPORT ,LONDON

NORTH LIGHT ROOF IN OFFICE BUILDING

NORTH LIGHT TRUSS IN FACTORY
Spiral Stair
 Geometrical stairs
 Continuous change in direction
 Normally not the main staircase
 Used to access areas having
limited entry
 Steel is them most common
material
 Other materials include- stones,
wood, concrete, glass, etc..
Spiral Stairs
Spiral stair with central column
• Most are made from steel and
welded together.
• Also available as prefabricated.
• Not very safe; have wider steps.
• Radius to center line of stairway
is not less than 600mm and not
more than 3000mm.
• Maximum width not more than
75mm.
IRON

STEEL

CONCRETE

WOODEN
GLASS
 Simplifies Installation, Planning and Layout

• A spiral staircase saves time

during the installation process

• The use of support footings

decreases from the multiple
required in a straight stair to
only 1 for a spiral stair