Steel sections-Building Construction

PRESENTED BY-ANJULA ROYRUBAL MEHTASUVRITI BAGAIII yr.-A

BUILDING CONSTRUCTION AND MATERIALS

TOPICS COVERED:1. STEEL TRUSSES2. TUBULAR SECTIONS3.ANGULAR SECTIONS

TRUSSES - OVERVIEW

WHAT ARE TRUSSES

?A TRUSS IS ESSENTIALLY A TRIANGULATED SYSTEM OF STRAIGHT INTERCONNECTED STRUCTURAL ELEMENTS. THE MOST COMMON USE OF TRUSSES IS IN BUILDINGS, WHERE SUPPORT TO ROOFS, THE FLOORS AND INTERNAL LOADING SUCH AS SERVICES AND SUSPENDED CEILINGS, ARE READILY PROVIDED. THE MAIN REASONS FOR USING TRUSSES ARE:

• LONG SPAN

• LIGHTWEIGHT

• REDUCED DEFLECTION (COMPARED TO PLAIN MEMBERS)

• OPPORTUNITY TO SUPPORT CONSIDERABLE LOADS.

• THE PENALTY, HOWEVER, IS INCREASED FABRICATION COSTS .

MATERIAL

REQUIREMENTS • SLENDER OR TUBULAR

MEMBERS• WOODEN STRUTS

(OPTIONAL)• METAL

BARS/ANGLES/CHANNELS• RIVETS, WELDS• GUSSET PLATE • ASSEMBLING APPARATUS

TYPES OF TRUSSES • KING POST & QUEEN POST

TRUSS.

• WARREN TRUSS.

• HOWE TRUSS.

• PRATT TRUSS.

• PARKER TRUSS.

• ENGLISH TRUSS.

• K- TRUSS.

• BALTIMORE TRUSS.

• CONTINUOUS TRUSS.

• BOWSTRING TRUSS.

• SAW-TOOTH TRUSS.

• SCISSOR

• WEDGE - THE TRIANGULAR PIECE OF LUMBER INSERTED BETWEEN THE TOP AND BOTTOM CHORDS, USUALLY TO ALLOW THE TRUSS TO CANTILEVER.

• BOTTOM CHORD - THE INCLINE OR HORIZONTAL MEMBER THAT ESTABLISHES THE BOTTOM OF A TRUSS, USUALLY CARRYING COMBINED TENSION AND BENDING STRESS.

• SPLICE - THE LOCATION AT WHICH TWO CHORD MEMBERS ARE JOINED TOGETHER TO FORM A SINGLE MEMBER. IT MAY OCCUR AT A PANEL POINT OR BETWEEN PANEL POINTS.

• PANEL POINT - ALSO CALLED A JOINT, IT'S THE LOCATION ON A TRUSS WHERE THE WEB MEMBERS AND TOP OR BOTTOM CHORDS INTERSECT AND ARE CONNECTED BY METAL CONNECTOR PLATES.

• WEB - THE MEMBERS THAT JOIN THE TOP AND BOTTOM CHORDS TO FORM THE TRIANGULAR PATTERNS TYPICAL OF TRUSSES.

• HEEL - THE POINT ON THE TRUSS WHERE THE TOP AND BOTTOM CHORDS INTERSECT

• SLOPE - THE VERTICAL RISE IN INCHES FOR EVERY 12 INCHES OF HORIZONTAL RUN.

• PANEL LENGTH - THE HORIZONTAL DISTANCE BETWEEN THE CENTERLINES OF TWO CONSECUTIVE PANEL POINTS ALONG THE TOP OR BOTTOM CHORD.

• PEAK - THE POINT ON THE TRUSS WHERE THE SLOPED CHORDS MEET.

• TOP CHORD - HORIZONTAL DISTANCE BETWEEN THE CENTERLINES OF TWO CONSECUTIVE PANEL POINTS ALONG THE TOP OR BOTTOM CHORD.

• CONTINUOUS LATERAL BRACE - MEMBERS INSTALLED AT RIGHT ANGLES TO A CHORD OR WEB MEMBER OF A TRUSS TO PROVIDE STABILITY TO THE TRUSS. ALL LATERAL BRACES MUST BE STABILIZED.

• OVERALL HEIGHT - VERTICAL DISTANCE BETWEEN BEARING AND THE UPPERMOST POINT OF THE PEAK.

• WEDGE - THE TRIANGULAR PIECE OF LUMBER INSERTED BETWEEN THE TOP AND BOTTOM CHORDS, USUALLY TO ALLOW THE TRUSS TO CANTILEVER.

• BOTTOM CHORD - THE INCLINE OR HORIZONTAL MEMBER THAT ESTABLISHES THE BOTTOM OF A TRUSS, USUALLY CARRYING COMBINED TENSION AND BENDING STRESS.

• SPLICE - THE LOCATION AT WHICH TWO CHORD MEMBERS ARE JOINED TOGETHER TO FORM A SINGLE MEMBER. IT MAY OCCUR AT A PANEL POINT OR BETWEEN PANEL POINTS.

• PANEL POINT - ALSO CALLED A JOINT, IT'S THE LOCATION ON A TRUSS WHERE THE WEB MEMBERS AND TOP OR BOTTOM CHORDS INTERSECT AND ARE CONNECTED BY METAL CONNECTOR PLATES.

• WEB - THE MEMBERS THAT JOIN THE TOP AND BOTTOM CHORDS TO FORM THE TRIANGULAR PATTERNS TYPICAL OF TRUSSES.

A KING POST IS ALSO KNOWN AS CROWN POST TRUSS. IT IS THE SIMPLEST FORM OF

TRUSS .IS USED FOR SIMPLE ROOF TRUSSES AND SHORT-SPAN BRIDGES.

KING POST TRUSS

QUEEN POST

TRUSS

IS SIMILAR TO A KING POST TRUSS. IT IS USED FOR SIMPLE ROOF TRUSSES AND SHORT-

SPAN BRIDGES. A SUPPORTING POST DESIGNED TO SPAN LONGER OPENINGS THAN A KING

POST.

A KING POST USES ONE CENTRAL SUPPORTING POST, WHEREAS THE QUEEN POST USES

TWO.

TYPES OF CONNECTIONS

• PINNED/BOLTED

CONNECTIONS • GUSSET PLATE

CONNECTIONS

• TUBULAR CONNECTIONS WELDED

CONNECTI

ONS

PINNED

CONNECTION

S

APPLICATION OF TRUSSES • ROOF OF FACTORY

SHADE.

• WARE HOUSE

• RAILWAY PLATFORM

• GARAGE SHED

• TRANSMISSION

TOWERS

• CRANE TRUSS

• BRIDGE TRUSS

• SPORT STADIUM

TRUSS

TUBULAR SECTIONS

(HOLLOW STRUCTURAL SECTIONS)-

HSS(TUBE STEEL, STRUCTURAL TUBING)

A TYPE OF METAL PROFILE WITH A HOLLOW

TUBULAR CROSS SECTION.

MEMBERS CAN BE CIRCULAR, SQUARE,

RECTANGULAR SECTIONS (OR ELLIPTICAL).

DIMENSIONS - BASED ON EXTERIOR DIMENSIONS

OF THE PROFILE.

HAS HEAVILY ROUNDED CORNERS-(RADIUS IS

AROUND TWICE THE WALL THICKNESS).

USES IN STRUCTURES RECTANGULAR SECTION- WELDED STEEL

FRAMES (LOADING ON MEMBERS IN MULTIPLE

DIRECTIONS).

SQUARE AND CIRCULAR –COLUMNS

(RESISTANCE TO TORSION), MULTIPLE AXIS

LOADING (EFFICIENT SHAPES- UNIFORM

GEOMETRY ALONG CROSS-SECTIONAL AXES,

THUS UNIFORM STRENGTH

CHARACTERISTICS).

BEAMS (SUPERIOR RESISTANCE TO LATERAL

TORSIONAL BUCKLING)

-ALTHOUGH WIDE FLANGE OR I-BEAM SHAPES

ARE A MORE EFFICIENT STRUCTURAL SHAPE

FOR THIS APPLICATION.

THE FLAT SQUARE SURFACES OF

RECTANGULAR CAN EASE CONSTRUCTION, (

ALSO FOR ARCHITECTURAL AESTHETICS IN

EXPOSED STRUCTURES)

-THOUGH ELLIPTICAL HSS ARE BECOMING

MORE POPULAR IN EXPOSED STRUCTURES.

BUILDINGS, HALLS-columns and lattice girders,

space frames for roofs; facades, etc.

BRIDGES

BARRIERS-(durability in such environment),

(corrosion resistant due to the rounded corners.)

OFFSHORE STRUCTURES- cranes, microwave

towers, flare supports, bridges and secondary

structures, such as staircases, ladders, etc.

TOWERS AND MASTS-wind loading, corrosion

•COMMONLY AVAILABLE IN MILD STEEL (A500

GRADE B)

•NOW AVAILABLE IN MILD STEEL-A500

GRADE C.

•OTHER STEEL GRADES AVAILABLE FOR HSS

ARE A847 (WEATHERING STEEL), A1065

(LARGE SECTIONS UP TO 50 INCH SQ MADE

WITH SAW PROCESS), AND A1085 (HIGHER

STRENGTH, TIGHTER TOLERANCES THAN

APPLICATIONS

TYPES

MANUFACTURESQUARE HSS-MADE THE SAME WAY AS PIPE.

PIPE CAN BE PRODUCED SEAMLESS OR

WELDED.

SEAMLESS SECTIONS-TWO PHASES,

1.PIERCING AN INGOT

2.ELONGATION OF THIS HOLLOW BLOOM

INTO A FINISHED CIRCULAR HOLLOW

SECTION.

THE EDGES ARE THEN WELDED TOGETHER

TO FORM THE MOTHER TUBE.

AFTER THIS PROCESS, THE TUBE CAN GO

THROUGH A SIZING MILL TO GIVE IT THE

REQUIRED DIAMETER (OR TO FORM THE

ROUND HSS (MOTHER TUBE) INTO THE FINAL

SQUARE OR RECTANGULAR SHAPE.-

THROUGH FORMING ROLLERS)

WELDED HOLLOW SECTIONS WITH A

LONGITUDINAL WELD ARE MAINLY

MADE WITH ELECTRICAL RESISTANCE

WELDING PROCESSES OR WITH AN

INDUCTION WELDING PROCESS.(FIG.1)

A STRIP OR PLATE IS SHAPED BY

ROLLERS INTO A CYLINDRICAL SHAPE

AND WELDED LONGITUDINALLY.

THE ROLLERS PUSH THE HEATED

EDGES TOGETHER, RESULTING IN A

PRESSURE WELD.

WELDING PROCESS

METRO CONNECTOR INDUCTION WELDING PROCESS

USE OF INTERNAL VOID

• OFTEN FILLED WITH

CONCRETE (THE PRODUCT IS

CALLED "LALLY COLUMN“)

• IMPROVED LOAD BEARING

RESISTANCE, COMPRESSIVE

STRENGTH,ROBUSTNESS.

• EXAMPLES- BARRIERS

AROUND PARKING

AREAS, BOLLARDS,ETC.

• WATER-FILLED HOLLOW

SECTION COLUMNS-

INCREASED FIRE RESISTANCE

TIME.

• INNER VOIDS-SOMETIMES

USED FOR AIR AND WATER

CIRCULATION FOR HEATING

AND VENTILATION OF

BUILDING -OFFERS

MAXIMIZATION OF FLOOR

AREA, FIRE PROTECTION.

• CONVEYING FLUIDS (PIPE

BRIDGE), RAIN WATER

DOWNPIPES, FOR ELECTRICAL

WIRING,ETC.

WIND FLOW FOR OPEN AND

CIRCULAR HOLLOW

SECTIONS

RAIN WATER DOWN PIPE

THROUGH A HOLLOW SECTION

COLUMN

ANGLE SECTIONS

TOE

ROO

T

MILD STEEL ANGLE IS A LENGTH OF STEEL OR

IRON THAT IS BENT AT A RIGHT ANGLE.

•ALSO KNOWN AS THE L-CHANNELS.

•THEY CAN BE MADE EITHER FROM A SINGLE

PIECE OF IRON OR STEEL BENT LENGTHWISE

TO A PARTICULAR ANGLE -- USUALLY 90

DEGREES – OR BY ATTACHING TWO PIECES

TOGETHER AT THE DESIRED ANGLE.

• THE LARGER THE STEEL ANGLE, THE MORE

WEIGHT AND STRESS IT CAN BEAR.

TYPES:

EQUAL

ANGLESTHE TWO LEGS OF

THE ANGLE

SECTIONS ARE OF

SAME DIMENSION

UNEQUAL

ANGLES

THE TWO LEGS OF

THE ANGLE SECTIONS

ARE OF DIFFERENT

DIMENSIONS.

DEFINITION

SIZES THE ANGLE SECTIONS ARE MANUFACTURED IN

DIFFERENT SIZES.

FIXING DETAILS

FIXING TO STEEL FIXING TO STONE AND CONCRETE

APPLICATIONS STEEL ANGLES ARE USED BROADLY, FROM MAJOR CONSTRUCTION

WORK TO BASIC HOME IMPROVEMENT, BUT THEY FALL INTO SEVERAL BROAD CATEGORIES.

• REINFORCEMENT

▫ STEEL ANGLES CAN BE USED AS BRACES TO HELP REINFORCE STRUCTURES. THE STRUCTURES CAN BE AS LARGE AND WIDE AS CEILINGS IN A SKYSCRAPER, OR AS SMALL AS THE CORNERS OF A DESK OR TABLE. BOLTING STEEL ANGLES TO THE CORNERS OF ANY CONSTRUCT WILL HOLD PIECES IN PLACE AND INCREASE THE STRUCTURE'S STRESS-BEARING CAPABILITY AND LONGEVITY.

• SUPPORT

▫ STEEL ANGLES CAN BE USED AS BRACKETS TO PROVIDE SUPPORT. THEIR MOST PREVALENT USE IS TO PROVIDE PLATFORMS FOR SHELVING, FROM A SIMPLE BOOKSHELF, TO EXTRA SPACE IN YOUR GARAGE TO HEAVY-DUTY STORAGE IN A LARGE WAREHOUSE. WHEREAS CORNER BRACES CAN BE INSTALLED IN ALMOST ANY POSITION, BRACKETS TEND TO BE PERPENDICULAR TO THE WALL TO PROVIDE A LEVEL MOUNT.

• FRAMEWORK

▫ A FRAMEWORK IS VITAL TO ANY STRUCTURE. NOT ONLY DO STEEL ANGLES HOLD SUCH

STRUCTURES TOGETHER, BUT LARGE ANGLES CAN FORM THE FRAME ITSELF. A36 STEEL IS A

POPULAR ALLOY USED TO CREATE THE "SKELETON" FOR MANY CONSTRUCTION PROJECTS.

STEEL ANGLES MAKE UP THE FRAMEWORK FOR MANY COMMON THINGS, INCLUDING

BUILDINGS, BEDS AND FACTORY MACHINES.

• DECORATIVE

▫ STEEL ANGLES CAN BE JUST AS EFFECTIVE IN THE FOREGROUND AS THEY ARE BEHIND THE

SCENES. THEY CAN BE USED AS DECORATIVE TRIM ON FURNITURE EDGES AND BUILDING

INTERIORS, INCLUDING DOORWAYS, COUNTERS AND FLOORS. MANY PEOPLE ALSO FIND

STEEL ANGLES USEFUL IN CREATING ATTRACTIVE BRICK LINTELS FOR INTERNAL FIREPLACES

AND EXTERNAL WINDOW SILLS.

APPLICATIONS (CONTD.)