Building techno

STRUCTURAL STEEL

Has a varied application in the construction industry. It is generally used in designing and building industrial places.

MILD/LOW STEEL, BULLET/RAIL STEEL, STAINLESS STEEL, and STRUCTURAL STEEL

GENERAL TYPES OF STEEL

MILD/LOW STEEL

Nearly pure iron having low carbon content, used in the manufacture of boilers, tanks, and enamelware

BULLET/RAIL STEEL

Made of scraps from railroad tracks that has superior compression resistance

STAINLESS STEEL

- Basically, an alloy of iron and about ten percent chromium which imparts remarkable resistance of the metal to corrosion and heat

STRUCTURAL STEEL

Streel rolled and extruded in a variety of shapes and fabricated for use as loadbearing sections.

CARBON STEEL,HIGH-STRENGTH, LOW ALLOY STEEL (HSLA),WEATHERING STEEL, and HEAT-TREATED STEEL

TYPES OF STRUCTURAL STEEL

CARBON STEEL

Contains carbon and manganese as the main alloys and is the basic structural steel: the most economical but has the lowest yield point (AISC ASTM designation A36)

HIGH-STRENGTH, LOW ALLOY STEEL (HSLA)

Offers reduction in weight and has twice corrosion resistance of A36; not recommended for welding

WEATHERING STEEL

Intended for exteriors; its brown coating (a kind of oxidation) protects it from further corrosion; has four times resistance of A36

HEAT-TREATED STEEL

Strength is developed by quenching and tempering; only available in plate sections.

FLANGED SECTION, CHANNELS, ANGLES, STRUCTURAL TUBING/ TUBES, STRUCTURAL PIPE/LALLY COLUMNS, STRUCTURAL TEES, PLATES, and BARS

STRUCTURAL STEEL PROFILES

FLANGED SECTION

- Wide Flanged (used as columns, commonly square) and I-sections or Standard Flange (used as beams, commonly rectangular) - Looks like letter I or letter H

CHANNELS

Used as walls studs, rafter beams and purlins

ANGLES

Commonly called angle bar or the L-angle

✓ Equal Leg Angles, and ✓ Unequal Leg Angles:

Types of Angles

STRUCTURAL TUBING/ TUBES

Square or Rectangle pipe-liked enclosed but structural profile is hollow.

STRUCTURAL PIPE/LALLY COLUMNS

Sometimes concrete filled for added strength

STRUCTURAL TEES

- Also known as the T – bar

- Similar to the wide flange but the difference it is sliced horizontally not vertically.

Plates

- Used for cold-formed/bended sections such as lipped channels.

- 4” x 8” in size similar to plywood size that is used as a customizable steel profile.

- Also used as a good bearing plate, bases or base plate.

BARS

- Structural steel profile that is SOLID INSIDE - Usually in smaller sizes - Used for ironwork and as concrete reinforcemen

✓ Flat Bar

✓ Square Bar

✓ Round Bar (plain/deformed)

Types of bars

Wide Flange

W

I-section/beam

S

Channel

C

Angle

L

Square Tubing

TS

Rectangular Tubing

TR

Pipe

P

S-Tee

ST

W-Tee

WT

Plate

PL

CRAWLER CRANES

(which operates from ground level) for low structures

TOWER CRANES

(which moves up at floor levels as the work in construction progresses) for exceptionally tall structures

1. Use of Fasteners 2. Welding

METHOD OF CONNECTING STRUCTURAL STEEL MEMBERS

FASTENERS

Inserted through holes made between steel sections, done by:

Punching

if thickness of section is equal to fastener diameter plus 1/8”, and;

Drilling

if thickness is greater than the criterion set in punching, note that holes are usually 1/16” larger than the fastener diameter.

BOLT (Threaded) and, RIVET (Plain)

TYPE OF FASTENERS

BOLT (Threaded)

Produces a friction type connection towards structural steel profile, has groves or screws in the bolt.

High-Strength/ Interference Bolts, and ✓ Machine Bolts/ Hex-Head Bolts

Types of bolts

High-Strength/ Interference Bolts

Used in construction projects, in structural steel

✓ Machine Bolts/ Hex-Head Bolts

▪ Used in non-structural projects

RIVET (Plain)

- Produces a bearing type connection - Can generate its own second head, by heating the excess through a metal plate and hammering it down to create a stopper

Button Head, Flat/Chipped Head, Pan Head, and Countersunk Head

Kinds of Rivet

BOLT

A metal pin with a head at one end with a shank or stem threaded at the other end on which a nut is screwed

NUT

A shout metal block having a central hole which is threaded to receive the threaded end of the stem of a bolt

WASHER

A flat, thin metal ring used as a bearing surface under the head and/or nut of a bolt; used to assure tightness, relieve friction, improve stress distribution, and to span large clearance holes.

RIVET

A malleable pin with a head at one end and a plain shank; used to join two metal sections by inserting it through a hole made between each section, deforming the other end of the shank to form a second head; holes can also be reamed to create flushed rivet heads (countersunk).

GAGE LINE, GAGE, and PITCH

FASTENER ARRANGEMENT AND PLACEMENT

GAGE LINE

- The line parallel with the length of a member wherein the fasteners are placed

GAGE

- The normal distance between two gage line or between a gage line and an adjacent edge of a member; minimum 3x plate thickness and 12x but not more than 15cm.

PITCH

- The center-to-center distance between adjacent fasteners, whether they fall on the same or different gage lines, and measured parallel to the direction of these lines. Minimum pitch is 3x fastener diameter but not more than 6x.

SHEAR FAILURE, BEARING FAILURE, TENSION FAILURE, and EDGE-TEARING FAILURE

MODES OF FASTENER FAILURE

WELDING

- The process of uniting metals by heating them to suitable temperatures, melting the parts together and allowing them to cool, causing fusion. This may be done usually with or without the application of filler metal (welding rods) and/or pressure.

GAS WELDING, and ARC/ELECTRIC WELDING

TYPES OF WELDING

GAS WELDING

- Coalescence in produced by a mixture of two or more gases; example is the combination of oxygen and acetylene to create combustion capable of melting as well as fusing metal components together

ARC/ELECTRIC WELDING

- The one generally used in building construction, wherein an electric arc is formed between an electrode (welding rod) and the two pieces that are to be joined. The intense heat partially melts these components resulting to fusion of the connection.