© 2010 Delmar, Cengage Learning Instructor Resources for Lesson C Material Basics.

© 2010 Delmar, Cengage Learning

Instructor Resources for

Lesson C

Material Basics



Wood Basics

• Characteristics– Inexpensive, strong, easy to work with, long-lasting

• If properly protected and maintained

– Combustible

• Framing uses softwood• Lumber may be classified as:

– Timber: 5 inches or thicker– Dimension: 2 to 4 inches thick and of any width– Boards: 1 to 1.5 inches thick and 2 inches or wider



Figure D-2 Dimension Lumber.



Wood Basics (cont’d.)

• Visual grading system– Based on size and use

• Moisture and shrinkage in unseasoned horizontal members– Can make floors uneven

• “Green” structural members – Can warp, twist, and shrink

• May cause connectors to fail



Wood Basics (cont’d.)

• Size of wood beam depends on:– Load it has to carry– Strength of the lumber

• Most common size of wood posts for residential and commercial buildings: – 4 × 4 feet, 4 × 6 feet

• Wood sheathing: – Plywood and oriented strand board (OSB) – Replaces boards for most applications



Figure S-1 Sheathing. (Courtesy of Kathleen Siegel.)



Courtesy of Craig Allyn Rose



Steel Basics

• Characteristics:– Versatile, uniform quality, and great strength in

compression and tension

• Standard grade in building construction– Carbon steel, ASTM grade A-36

• Loses strength at 1000° F• Popular in commercial and industrial buildings



Steel Basics (cont’d.)

• Decking – Supports concrete slabs and suspended ceilings

• Exterior walls: – Metal panels, precast curtain walls, or masonry

• Common hot-rolled steel shapes – Wide-flange beam (W); American Standard Beam (S)

• Cold-formed structural shapes– Used for secondary members in pre-engineered metal

buildings



Figure S-17 Suspended Ceilings. Figure C-20 Curtain Wall.



Figure P-13 Purlin. (Courtesy of Kathleen Siegel.)

Figure S-13 Strut.



Steel Basics (cont’d.)

• Steel studs – Used in Type I Fire Resistive and Type II Non-

combustible buildings– Size/gauge dependent on location/loading conditions

• Steel columns – Wide flange, pipe, and structural tubing

• Steel decking – Flat or ribbed 12- to 16-gauge sheets– Used for floors/roofs with poured-over concrete slabs



Masonry Basics

• Characteristics– Durable– Fire- and heat-resistant – Sound-insulating properties– Fast and easy to put up; little maintenance– Choices of texture, color, style, and pattern– Heavy material, high compression strength

• Requires steel reinforcement in earthquake zones

– Little tensile or flexural strength



Masonry Basics (cont’d.)

• Typical examples– Concrete block, brick, and stone with mortar and/or

grout

• Uses– Load-bearing and nonbearing walls for interior and

exterior applications– Below and above grade for piers and columns, fire

walls, and curtain walls

• ASTM grades describes structural properties



Figure F-7 Fire Wall. Figure R-3 Rebar.



Masonry Basics (cont’d.)

• Concrete masonry units (CMUs)– Typically 8 × 8 × 16 inches– Used for wall thicknesses of 8 to 16 inches

• Steel connectors– Joins masonry walls with wood/steel roofs and floors

• Unprotected wide-flange beams– Support floors and roofs – Susceptible to elongation when heated– May cause failure of the masonry wall



Concrete Basics

• Characteristics– Noncombustible, heavy, and brittle material with

great compressive strength

• Uses: floors, walls, roofs, columns, beams • Steel reinforcement necessary for floors,

foundations, columns, and beams• Prestressing develops greater load-carrying

capabilities with less weight• Pretensioning used for precast concrete



Concrete Basics (cont’d.)

• Posttensioning used for cast-in-place concrete

• Thickness of exterior concrete walls:– Depends on design load and fire-resistance

requirements

• Precast tilt-up walls are usually cast off-site• Walls are cast on-site• Wall panels are lifted and then braced to the

floor slab



Figure C-2 Cast-in-Place Concrete.



Concrete Basics (cont’d.)

• Panels are joined together by:– Welding them to steel columns– Joining them to cast-in-place concrete pilasters

• Concrete beams: – Typically rectangular– Used to carry floor and roof loads– Reinforced with steel to resist tension

• Prestressing beams– Creates greater load-carrying capacity



Summary

• Wood– Inexpensive, strong, easy to work with, long-lasting,

but combustible

• Steel– Versatile, uniform quality, and great strength

• Masonry– Durable, fire- and heat-resistant, sound-insulating

• Concrete– Noncombustible, heavy, great compressive strength

© 2010 Delmar, Cengage Learning Instructor Resources for Lesson C Material Basics.

Documents

Transcript of © 2010 Delmar, Cengage Learning Instructor Resources for Lesson C Material Basics.