Building Construction IV Steel Construction

7/29/2019 Building Construction IV Steel Construction

1/47

BUILDINGCONSTRUCTION

IVSTRUCTURAL STEEL CONSTRUCTION


2/47

4. STRUCTURAL STEEL CONSTRUCTION4.0

4.1

Structural Steel

Construction

Structural Steel Shapes

Structural Steel Framing

Steel Columns &

Connections

Steel Beams &

Connection

Open-Web Steel Joists

Metal Decking

Steel Trusses and RigidFrames


Systems

Joining of Steel

Members

4.1 STRUCTURAL STEEL SHAPES

The most common shapes of structural steel used in buildings are the American

Standard Steel Shapes such as:

1. Square Bars

2.

3. Round Bars

4. Plate Bars

5. Angle Bars

6. Channels The standard channel has the shape of unsymmetrical balanceconsisting of two flanges on one side. It requires lateral support to prevent its

tendency to buckle. Channels are generally used as parts of built-up sections

for columns and are also suitable for framing around floor openings, spandrels

and lintels attributed to the absence of flanges on the other side. The channelsection is identified as C 15 x 20 which means that the channel has a depth of

20 cm and weights 15 kg per meter length.

7. I-Beams The use of a standard I-beam as a column is uneconomical

because the whirl or revolving action of the member about an axis through the

centroid of the web is comparatively small.


3/47

4.0

4.1

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

7. Tee Beams

8. H-Columns

9. Wide Flanges Wide Flange sections are designated as W 12 x 24 whichmean that the flange has a depth of 24 cm and weighs 12 kg per meter

length. All wide flange sections are generally with parallel face flange

except those with 5% slope inside face produced by Bethlehem Steel

Company. Comparatively, wide flange sections are more efficient than

standard I-beams with respect to bending resistance.

10. Zees The zee section is another structural form in a letter Z which is notfrequently used in building construction except for the fabrication of steel

windows and other frames.


4/47

4.0

4.2

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.2 STRUCTURAL STEEL FRAMING

Structural steel girders, beams, and columns are used to construct a

skeleton frame for structures ranging in size from one-story to

skyscrapers. Because structural steel is difficult to work with on site, it

is normally cut, shaped, and drilled in a fabrication shop according todesign specifications; this can result in relatively fast, precise

construction of a structural frame. Structural steel may be left exposed

in unprotected non-combustible construction, but because steel can

lose strength rapidy in a fire, fire-rated assemblies or coatings are

required to qualify as fire-resistive construction.

The three major types of framing systems are the following:

4.2.1 One-Way Beam System eachpair of external columns supports a

long-spanning beam or girders. This

form of construction is suitable for

long, narrow buildings, especially

when a column-free space is desired.

The absence of columns in the interioris an advantage in structures such as

car parks, as freedom from

obstruction makes for greater and

safer maneuverability, besides

allowing the layout of the parking

spaces to be altered at any time.


5/47

4.0

4.2

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.2.2 Two-Way Beam Systema two-layer system, where beamsframe into girders, increases floor depth considerably and provides

more space for mechanical systems. Steel girders span the short axis

of a building bay thus contributing to the lateral stability of the structure.


6/47

4.0

4.2

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.2.3 Three-Way Beam System is used when a large column-free space is required, where long-spanning plate girders or

trusses can be used to carry the primary beam, which in turn

support a layer of secondary beams.


7/47

4.0

4.3

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.3 STEEL COLUMNS AND CONNECTIONS

4.3.1 STEEL COLUMNS

Steel columns are of the following types:

a. Struts of one or two angles. These

are used for compression members in

roof trusses, light towers, and lattice

girders. The two angles of a double

struts are riveted together by rivetsdriven through washers placed

between the two angles at intervals of

4 to 6 ft.

b. Starred angles of two or four

connected by batten plate spaced atintervals of 3 to 4ft. These are used

to support the light loads.


8/47

4.0

4.3

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

c. Latticed Columns made up of channels orangles connected by lattice bars are often

used where light loads are to be supported on

long columns.

d. Rolled H-columns. These are obtainablewith depths ranging from 6 to 16 and are

now commonly used instead of built-upcolumns in steel skeleton construction.

e. Built-up Columns. These are usually of H-shaped section formed by acombination of plates and angles although box columns with two or more

webs are not uncommonly used in heavy building frames.


9/47

4.0

4.3

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

f. Top Chord sections of heavy trusses are

usually unsymmetrical and are made of two

rolled or built-up channel sections and a cover

plate. The open (bottom) side of the section is

latticed.

g. Columns for bents are sometimes made upof a pair of channels and an I beam with batten

plates at intervals of 3 to 4 ft. connecting the

flanges of the channels. Columns made of four

angles and a web-plate are commonly used in

mill building bents.

h. Battened columns are those in which twocomponent parts of the column are connected

only by batten plates. They are decidedly

inferior to latticed columns and should be

avoided if a continuous plate or latticing can be

used instead.


10/47

4.0

4.3

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

In the design of steel columns the following should be taken into

consideration: No part of a steel column should be less than 1/4 thick. No

material whether in a body of the column or used as a lattice bar or stay

plate, shall be of less thickness than 1/32 of its unsupported width,

measured between centers of rivets transversely, or 1/6 of the distance

between center of rivets in the direction of stress. Tie-plates are to have

not less than 4 rivets and are to be spaced so that the ratio of length to the

least radius of gyration of the parts connected does not exceed 40, the

distance between nearest rivets of two stay plates in this case being

considered as length. In built-up columns the thickness of any outstanding

member (for example, the outstanding legs of angles) shall not be less

than 1/12 of the width of the outstanding portion.

Base plates for steel column are usually made of steel plates and shapes.

Cast-iron bases are sometimes used for very heavy columns. Ribbed

cases may also be used instead of plates and when bolted to the columns,

add greatly to the stability of the supporting members because of their

greater width.


11/47

4.0

4.3

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.3.2 LALLY COLUMNS

These are columns made up of a cylindrical

steel pipe shell filled with 1:1-1/2:3 Portland

cement concrete. The standard type of lally

column is reinforced with only the steel pipe

shell. Special types of columns are obtainable

with additional reinforcement consisting of steel

pipe, reinforcing bars or structural steel shapes.

The light weight column is 4 in outside diameter

with a shell thickness of 0.134, while the heavy-weight columns are from 3-1/2 to 12-3/4 inches

in outside diameter with shell thicknesses of

0.216 to 0.375 inches.

4.3.3 COMPOSITE COLUMNS

These are columns in which a concrete core is further reinforced with a

steel or cast-iron core designed to support a part of the load. Steel

cores may be structural H-sections or four angles, latticed or battened;

cast-iron cores are usually either solid shafts or hollow pipe sections.

The column may be further reinforced by vertical rods or bars placed

at the circumference and enclosed by spirals.


12/47

4.0

4.3

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.3.4 STEEL COLUMN CONNECTIONS


13/47

4.0

4.4

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.4 STEEL BEAMS AND CONNECTIONS

4.4.1 STEEL BEAMS

Steel beams may be rolled in the shape of the letter I (I-beams), channelbeams orangles. Beams of T shape were formerly used but have nowbeen restricted to minor uses. The I-beam is the ideal type of steel beam.

The horizontal portion is the web. Channels are sections of this shape:

They vary in depth from 3 to 15, and in weight from 4.1lb. per ft. to 55lb.

per ft.


14/47

4.0

4.4

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

Girders may be built up of angles and plates riveted together for long spans

and for unusual cases of very heavy loading. Those are of two types:

a. Plate Girders. A plate girder is a beamcomposed of a wide plate, known as a

web, at the top and bottom of which are

riveted angles and plates. The simplest

type of plate girder consists of a web and

four flange angles. If this does not give

sufficient flange area, cover plates may be

added. The web may be frequentlyreinforced against buckling by angles

riveted to its sides, known as stiffener

angles.

b. Box Girders. This is a built up

beam in which more than one webplate is used.


15/47

4.0

4.4

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

Beams and girders may be connected to columns by either seated connections or

framed connections.

In a seated connection the bottom flange of the beam rests on and is field-rivetedto an angle shop-riveted to the flange or web of the column. Another angle is field-

riveted to the column and to the top flange of the beam.

In a framed connection the web of the beam or girder is connected by angles or by

gusset-plates to the column. In framed connections, angle seats are usually shop-riveted to the columns to hold the beam or girder during erection.

4.4.2 STEEL BEAM CONNECTIONS

Moment Connections AISC Type 1 also called Rigid Frame

connections are able to hold their original angle under loading by developing

a specified resisting moment, usually by means of plates welded or bolted to

the beam flanges and the supporting column.


16/47

4.0

4.4

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

2. Shear Connections AISC Type 2Simple Frame connections are

made to resist only shear and are free to rotate under gravity loads. Shear walls

or diagonal bracing is required for lateral stability of the structure.

3. Semi Rigid Connections AISC Type 3Semi-Rigid Frame

connections assume beam and girder connections possess a limited but

known moment resisting capacity.

S l S l


17/47

4.0

4.5

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.5 OPEN-WEB STEEL JOISTS

Open web joists are lightweight, shop fabricated steel members having atrussed web. A K series joist has a web consisting of a single bent bar,

running in a zigzag pattern between the upper and lower chords. The LHand DLH series joists have heavier web and chord members and are for

increased loads and spans.

St t l St l


18/47

4.0

4.6

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.6 METAL DECKING

Metal decking are corrugated steel panels used as a working platformduring construction and eventually as formwork for sitecast concrete

slab. The decking panels are secured with puddle-welds or shear weldedthrough the decking to the supporting steel joists or beams. The panels

are fastened to each other along their sides with screws, weld, or button

punching standing seams. If the deck is to serve as a structural

diaphragm and transfer lateral loads to shear walls, its entire perimeter is

welded to steel supports. In addition, more stringent requirements to

support and side lap fastening may apply. There are three major types of

metal decking:

Structural Steel


19/47

4.0

4.6

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.6.1 Form Decking serves as apermanent formwork for a reinforced

concrete slab until the slab can

support itself and its live load.

4.6.2 Composite Decking

serves as a tensile reinforcement

for the concrete slab to which it is

bonded with embossed rib pattern.

Composite action between the

concrete slab and the floor beams

or joists can be achieved by

welding shear studs through thedecking to the supporting beam

below.

4.6.3 Cellular Decking is

manufactured by welding a

corrugated sheet to a flat steel sheet,

forming a series of spaces orraceways for electrical and

communications wiring; special

cutouts are available for floor outlets.

The decking may serve as an

acoustic ceiling when the perforated

cells are filled with glass fiber.

Structural Steel


20/47

4.0

4.7

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.7 STEEL TRUSSES AND RIGID FRAMES

4.7.1 ROOF TRUSSES

A truss is a structural framework composed of a series of straight

members so arranged and fastened together that external loads applied toit will cause only direct stress in the members. The upper and lower

members of a truss are called the top chord and bottom chord

respectively. The members of the truss which are framed between and join

the top and bottom members are called web members.

When the external loads act downward and the truss is supported at the

ends, the top chord is always in compression and the lower chord always intension, similar to the upper and lower flanges of a beam. The web-

members are subjected to stresses of either tension or compression. Web-

members subjected to tensile stresses are called tension web-members;those which are subjected to compression are called compression web-

members. In certain positions, a web-member may be subjected to tension

through the action of a load applied at one point, and when applied at

another point that load may produce compression in the member so that atone time it will be subjected to tension and at another time to compression.

Such a member, design to resist either tension or compression, is called a

counterbrace. A member of a truss system which acts only for a particularpartial loading, and which has a zero stress when the truss is completely

loaded is called a counter.

Structural Steel


21/47

4.0

4.7

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

When a truss is supported at its ends by columns, the truss together with

its columns, considered as a unit, is called a bent.

The intersection between two or more members of the truss is called a

joint or panel joint and the distance between two adjacent joints along

either the top or bottom chords is known as the panel or panel length. The

quadrangular space, crossed by an inclined web-member, is also referred

to as a panel. The axes of all members at each joint should always meet

in a common point.

The span of a roof truss is the distance between the centers of thesupports and its rise is the distance between the apex of the truss and the

line joining the points of support. The pitch of a roof truss is the ratio of the

rise to the span for a truss symmetrical about its center line. The slope of

an inclined member is the tangent of the angle of inclination with the

horizontal, usually specified in inches rise per 12 run.

The portion of the roof between two adjacent trusses is called a bay.

4 0Structural Steel


22/47

4.0

4.7

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4 0Structural Steel


23/47

4.0

4.7

Structural Steel

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.7.2 TYPES OF TRUSSES

A. RELATIVE TO THE NUMBER AND ARRANGEMENT OF THE

MEMBERS COMPOSING THE TRUSS.

1. Complete Frame. A complete structural frame, or truss, is one in

which is made up of the minimum number of members required to

provide a complete system of triangles fixing the relative positions of a

given number of panel joints. If the number of panel points in the given

structure and n = the number of necessary members.

n = 2p 32. Incomplete Frame. One in which the number of members is less thanthat required by the equation given above.

3. Redundant Frame. A redundant frame is one which contains moremembers than that required by the equation given above.

4 0Structural Steel


24/47

4.0

4.7

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

B. RELATIVE TO FORM

1. Triangular

2. Quadrangular

3. Crescent

4. Scissors

5. Arched

4 0Structural Steel


25/47

4.0

4.7

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

C. RELATIVE TO METHOD OF SUPPORT

1. Simple Truss. A truss supported at each end-point.

2. Overhanging end span. A truss supported at one end-joint and other joint not

an end-joint.

3. Cantilever span. A truss where the entire support is at one end only.

Panel Length

Truss Plate

Peak

Top Chord

Heel

Overhang Bottom Chord Length

CantileverSpan (Out to Out of Bearings)

Web

Bottom ChordBearing Point Panel Point

Splice Wedge Block

Continuous Lateral Brace

SlopePitch

4 0Structural Steel


26/47

4.0

4.7

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

D. RELATIVE TO ARRANGEMENT OF THE WEB-BRACING SYSTEM1. Fink 5. Hammer-beam2. Howe 6. Sawtooth3. Pratt 7. Warren4. Scissors 8. Pettit

FINK

HOWE

PRATT

SCISSORS

SAWTOOTH

WARREN

PETTIT

4.0Structural Steel


27/47

4.0

4.7

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.0Structural Steel

C t ti 4 6 3 RIGID FRAMES


28/47

0

4.7

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.6.3 RIGID FRAMES

Rigid frames consist of two columns and a beam or girder that are rigidly

connected at their joints. Applied loads produce axial, bending and shear forces

in all members of the frame since the rigid joints restrain the ends of the

members from rotating freely. In addition, vertical loads cause a rigid frame todevelop horizontal thrusts at its base. A rigid frame is statically indeterminate and

rigid only in its plane.

4.0Structural Steel

C t ti


29/47

4.8

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.8 STRUCTURAL STEEL FRAMING SYSTEMS

4.8.1 ARRANGEMENT OF VERTICAL COMPONENTS

4.0Structural Steel

Construction


30/47

4.8

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.0Structural Steel

Construction 4 8 2 STRENGTHENING THE FRAMING SYSTEM


31/47

4.8

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.8.2 STRENGTHENING THE FRAMING SYSTEM

The framing system can be stiffened against horizontal forces in the following

three (3) methods:

1. The structure is composed of rigid frames which may comprise some hingedjoints but there must be sufficient rigid joints to ensure that none of the nodes

of the frame is free to move sideways. The members may be straight or

curved and a variety of shapes may be chosen for such framed structure.

4.0Structural Steel

Construction


32/47

4.8

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

2. A bracing system which consists of a triangulated framework of rolled

sections will hold the joints together and further strengthen the

framework against lateral loads. The center lines of members

converging at a joint should intersect at one point. The joints

themselves are conventionally assumed to be hinged, so that the

members are either ties or struts, loaded purely in tension orcompression, respectively. However, the overall bracing effect of a

lattice system can be enhances by constructing it with tiff members and

rigid joints.

4.0Structural Steel

Construction


33/47

4.8

Construction



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

3. Finally, shear walls in the form of more or less solid diaphragms,

usually of reinforced concrete, transmit the wind and earthquake

forces by shear and bending.

4.0Structural Steel

Construction


34/47

4.8



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking



Systems

Joining of Steel

Members

4.8.3 The Ultimate Structures for Skyscrapers

THE TUBULAR FRAME

The high-rise building conceived as a rigid tube ---

If a high-rise building is of suitably compact shape on plan (circular,

square, not too narrow a rectangle), the external columns can be

structurally merged with the external lattice bracing or with

spandrel girders so as to form a vast rigid tube. This stiffening

system is particularly effective and economical. This is due not only

to the optimum distribution of the bracing, but also more

particularly to the co-operation of all the columns and bracing or

spandrel girders in the external walls.

4.0Structural Steel

Construction The John Hancock Center, Chicago (architects:


35/47

4.8



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking

Steel Trusses and Rigid

Frames


Systems

Joining of Steel

Members

The John Hancock Center, Chicago (architects:

Graham and Skidmore, Owings and Merrill)

employs the tube in its framing system. In this 335

m high 100-story building, all the horizontal forces

are transmitted through external bracing, whereby

a substantial saving has been achieved incomparison with a bracing system located in the

interior. The external lattice members form a

distinctive architectural feature.

4.0Structural Steel

Construction


36/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

4.9 JOINING OF STEEL MEMBERS

Steel shapes can be joined in the building frame using any of the

following fastening methods:

4.9.1 RIVETING

A rivet is a short pin, of malleable metal such as iron, steel, or copper,

with a head at one end; used to unite two metal plates by passing it

through a hole in both plates and then hammering down the point to

for a second head.

In structural riveting, a hot steel rivet with a formed head is inserted in

holes through two members to be joined; its head is then held with a

hand hammer with a cup shaped depression, while a pneumatic

hammer drives a rivet set repeatedly against the other end to form asecond head. The rivet shrinks as it cools, drawing members tightly

together.

Rivet set, rivet snap, settoing punch, snap a tool for shaping the head of a rivet.

4.0Structural Steel

Construction


37/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

The types of rivet heads are:

Countersunk, raised

Countersunk, flat

Button, coned neck Button, straight neck

Pan, coned neck

Pan, straight neck

The bolts commonly used in steel frame construction falls into two general

categories:

Carbon-steel bolts or common bolts; are similar to the ordinarymachine bolts. Carbon steel is steel having no specified minimum

content of alloying elements; minimum copper content not exceeding

0.40%.

High-strength bolts are bolts made of either high-strength carbon steel

or quenched and tempered alloy steel; tempered meaning, heat

treated during manufacture to develop the necessary strength. It is

usually tightened using pneumatic or electric impact wrench.

4.9.2 BOLTING

4.0Structural Steel

Construction


38/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

A major problem in high strength bolting or friction type connections is how

to verify the necessary tension has been achieved in all the bolts in a

connection.

There are several ways to achieve proper tightening:

Turn-of-nut method

Load indicator washer

Tension control bolts

4.0Structural Steel

Construction


39/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

4.9.3 WELDING

Welding has become fully accepted as a means of joining steel structural

members in buildings because it has the inherent advantage of fusing

the metals to be joined, thereby simplifying connections andfabricating operations.

A. DEFINITION OF FUSION WELDING (ELECTRIC ARC WELDING)

The fusion welding process employs an electric arc, wherein energy in the

form of heat is supplied by establishing an arc between the base orparent metal (the parts to be joined) and a metal electrode. As the arc

is formed, tremendous heat is concentrated at the point of welding.

Instantly, the materials are at melting-point temperature.

The parent metal melts in a small pool and additional metal supplied by

the electrode is transferred through the arc an deposited in the pool.

As the electrode continues along the joint, the molten metal left behindsolidifies to form the weld.

4.0Structural Steel

Construction 4.8.2 COATED ELECTRODES


40/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

Most welding is done with coated electrodes. The function of the coating

is to form a gaseous shield, which protects the arc and molten metal

from contact with the air. Oxides and nitrides resulting from contact

with the air tend to produce brittle welds. The coating also forms aslag-fuse shield, which floats above the molten metal, protecting it

from the atmosphere. The slag is easily removed after the weld has

cooled.

The size and strength of weld is determined by the length of its leg.

For an E60 electrode on A36 steel, the allowable stress may becomputed on the basis of 800 pounds per linear inch per 1/16 inch

of leg size.

For A36 steel or higher-strength steels up to Fy = 60 ksi, an E70

electrode should be used and the the allowable stress may be

computed on the basis of 930 pounds per linear inch per 1/16 inch

of leg size.

4.0Structural Steel

Construction


41/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

4.0Structural Steel

Construction


42/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

C. TYPES OF WELD

FILLET WELD is of approximately triangular section joining two

surfaces approximately at right angles to each other. The fillet weldis the most common type of weld used in structural work.

GROOVE WELD is made by depositing filler material in a groovebetween two members to be joined. The standard types of grooves

are square, V, bevel-U, and J. With the exception of the square

groove, all grooves may be either single or double.

PLUG or SLOT WELD is made of a circular hole (plug) or anelongated hole (slot) in one member of a lap joint, joining that

member to the portion of the surface of the other member that is

exposed through the hole.

4.0Structural Steel

Construction


43/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

4.0Structural Steel

Construction

D. WELD POSITIONS

Th f iti i ldi I d f th th fl t h i t l


44/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

There are four positions in welding. In order of economy, they are the flat, horizontal,

vertical, and overhead positions. Overhead welds, which is the most difficult, should be

avoided whenever possible.

E. WELD JOINTS

The three most common joints used in structural work are the butt, T, and lap joints.Other types are the edge and corner joints. Fillet welds are applicable to T, lap, andcorner joints; groove welds are applicable to all joints with the exception of lap joints.

4.0Structural Steel

Construction


45/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

STANDARD WELDING SYMBOLS

4.0Structural Steel

ConstructionWELDING SYMBOLS Examples of use


46/47

4.9



Steel Columns &

Connections

Steel Beams &

Connection


Metal Decking


Frames


Systems

Joining of Steel

Members

BUILDING


47/47

END

BUILDING

CONSTRUCTION

4

Building Construction IV Steel Construction

Documents

Transcript of Building Construction IV Steel Construction