8.2s KNOW CONSTRUCTION MATERIALS & THEIR PROPERTIES Flashcards
S1 - EFFECTIVE STRUCTURAL BUILDING MATERIALS COMPRISE OF
- Stiffness w Elasticity
* Resist Dimensional Instability due to Humidity & Temp.
S2 - QUALITIES OF WOOD AS A STRUCTURAL MATERIAL
• SMALL • RENEWABLE • FLEXIBLE
• LIGHT • EXPOSED TIMBER
* GOOD IN COMPRESSION & TENSION
S3 - QUALITIES OF CONCRETE AS A STRUCTURAL MATERIAL
• FREEDOM OF FORM • NATURALLY FIRE PROTECTED
• EXPOSED STRUCTURE • INEXPENSIVE
* GOOD IN COMPRESSION - MUST BE PAIRED WITH STEEL REINFORCING FOR TENSION
S4 - QUALITIES OF STEEL AS A STRUCTURAL MATERIAL
- REPETITIOUS MODULAR • LONG SPANS
* LIGHT • STIFF & ELASTIC
S5 - WHAT IS CONCRETE MIX COMPRISED OF?
+ CEMENT (PORTLAND)
+ WATER
+AGGREGATE
S6 - WHAT KIND OF CEMENT IS PORTLAND CEMENT AND HOW IS IT MADE
• HYDRAULIC CEMENT
1 - BURN CLAY & LIMESTONE IN A KILN
2 - PULVERIZE INTO FINE POWDER
S7 - 5 TYPES OF CONCRETE
TYPE I - NORMAL TYPE II - MODERATE PORT. CEMENT TYPE III - CURES FASTER (COLD WEATHER) TYPE IV - LOW HEAT TYPE V - SULFATE RESISTANCE (salty acidic soil)
S9 - CONCRETE MIX CONTAINS __-__% AGGREGATE.
60-80%
THIS IS KEY TO •FR •STRENGTH •WEIGHT
S10 - SIZE OF FINE & COARSE AGGREGATE. WHAT IS APPROPRIATE DEPTH & THICKNESS FOR SLAB & WALLS RESPECTIVELY?
FINE: sand < 6mm COARSE: (Abram's Law) must be <1/3 slab depth must be <1/2 wall thickness
S11 - RELATIONSHIP OF WATER-CEMENT RATIO TO STRENGTH + IDEAL RANGE:
- Compressive strength inversely proportional to ratio of water to cement.
- IDEAL RANGE .45-.60
S12 - LIGHTWEIGHT CONCRETE MADE WITH _______ OR ___________.
EXPANDED SHALE OR SLATE AGGREGATE
S13 - INSULATING CONCRETE MADE WITH _________
PERLITE AGGREGATE OR FOAM AGENT.
S14 - Describe the advantages of WOOD as a structural material. (6)
\+ strong \+ durable \+ light \+ rigid & flexible \+ easy to work w \+ renewable
S15 - What are the 2 major classes of wood?
*do NOT describe hardness 1 - SOFTWOOD = used for construction • predominantly evergreen • pine/fir 2 - HARDWOOD = used for finishing • predom. broad leaf flowering trees • Cherry/Oak/Maple
S16 Wood is great in tension and compression, but the grain should be considered. Describe the strength of wood cut:
1 - Parallel to the grain
2 - Perpendicular to the grain
1 - Parallel = BEST for tension and compression
(1/3 stronger in compression)
2 - Perp = best for shear strength
(allowable force = 1/5-1/2 that of parallel)
S17 What is impacted by the cut of a log? (4)
1 - strength
2 - insulative value
3 - expansion/contraction
4 - how it is joined
S18 What are the 2 main types of log cutting?
1 - PLAINSAW $ • varied grain / twisting 2 - QUARTER SAW \$\$$ (aka vertical grain) • better quality
S19 Why do we season wood?
To season wood is to dry in a kiln to:
1 - reduce moisture
(shrinking <30%
2 - protect against decay (shrinking <20%)
S20 What are common lengths for lumber.
in 2’ increments:
6’ (1830) - 24’(7315)
S21 What are these 2 types of lumber:
1 - yard lumber
2 - factory + shop lumber (4 purposes)
1 - yard lumber
• sawn/selected for further manufacture
• ie. doors/millwork
• graded according to useable wood
2 - factory + shop lumber
• softwood lumber for general building purposes inc:
• boards (<2” thick)
• dimensional lumber (joists/light frame)
• structural lumber (beams/stringers)
• timbers (typ. left in green undressed condition)
S22 What is a good rule of thumb when estimating depth for beams and girders.
Beam span/20
Girder span/15
S23 What is more structurally efficient an S(often called I) beam or a W beam
A W beam is a profile engineered to carry the load more efficiently.
S24 Describe the 3 types of metal structural connections.
1 - MOMENT (this sh*t is locked down)
• rigid frame
• connections hold original angle under loading of welded plates
2 - SHEAR
• simple frame
• connections resist shear loads only .: can rotate
3 - SEMI-RIGID
• semi-rigid frame
• assume limited but known moment resistance capacity
S25 What are the 2 basic types of steel?
1 - Structural Steel • hot rolled • strong • versatile (1 storey up to towers) 2 - Lightweight Steel • details sim. to wood frame • low rise • on-site erection = good for irregular shapes
S26 What are the 2 types of open web steel joists?
STANDARD (K series ) • zigzag = single bent bar • span = 4 - 18m • depth 100-150mm LONGSPAN (LH & DLH series) • heavier web/chord members • great for heavier loads + longer spans • span = 8 - 18m (DLH can span up to 144') • depth = 150-305mm
**compare:
24K9 = acceptable span 7-14m
24LH7 = acceptable span 11-14m
note: chord is larger on K series
S27 How would you read the sizing for an open-web joist? example: 24K9
24K9
24” Depth of joist
K Joist series
9 Chord designation
S28 Good rule of thumb for estimating open web steel joists.
SPAN should not exceed 24xs the JOIST DEPTH.
S29 What size of overhang is acceptable for the K open web joist series?
5’6” with an allowable load of 300 psf
S30 What must be done is metal decking is acting as a diaphragm, transferring lateral loads to shear walls.
MUST be welded to steel supports along entire perimeter.
S31 Describe 3 most commonly used metal decking types.
FORM DECKING
• perm. formwork for reinforced conc. slab
COMPOSITE DECKING
• serves as tensile reinforcement for con. slab to which it is bonded with it’s ribs
CELLULAR DECKING
• weld flat sheet to underside of corrugated
=raceways for elec. + comms
* may also serve as acoustic ceiling if perf. flat sheet filled w glass fiber.
S32 What are the advantages (3) and disadvantage of using lightgauge steel joists?
+ lighter/longer spans + more dim. stable than wood
+ easily cut/tooled onsite
+ prepunched holes for bridging/piping/wiring
- they conduct more heat than wood and have more embedded energy
S33 What is a good rule of thumb for estimating solid wood beam sizing? And glulam?
Wood depth = span/15
Glulam depth = span/20
S34 If gypsum is used as a corner brace what 2 addition installation measures must be taken?
1 - must be nailed to stud base
2 - adhesive used
S35 List 3 types of wood columns:
• SOLID
• BUILT UP - glue-lam or mech fast.
(cannot take as much load as same size solid)
• SPACED
S36 What are the 2 most common modular block types for structural masonry walls?
1 - Bricks = heat hardened
2 - Blocks (concrete) = chemically hardened
S37 Mortar is a mix of cement and/or lime w water and sand. What makes each of these unique: 1 - Cement Mortar 2 - Lime Mortar 3 - Cement/Lime Mortar 4 - Masonry Cement
1 - Cement Mortar • portland cement • water • sand 2 - Lime Mortar rarely used 3 - Cement/Lime Mortar •cement mortar + lime = increased plasticity and water retention 4 - Masonry Cement • proprietary mix of port.cement w lime and plasticizers = rqr only the addition of sand and water
S38 List the 5 types of mortar. (based on strength)
M - high strength
• use: reinforced masonry below grade or in contact w earth
S - med - high strength
• use:bond lat. strength more import than comp.
N - med strength
• use: above grade where high lat./comp. strength NOT rqrd
O - Low strength
• use: int. non-LB partitions
K - Very low strength
• use: int. non-LB partitions
S39 What are form ties? List 2 types
SNAP TIES
- have notches or crimps so they can be snapped off after forms are removed
SHE BOLTS
- waler rods (reused) threaded into inner rod which is left in concrete
S40 List the 3 most common precast concrete wall types
SOLID - 8’ width typ.
(max height 7m)
COMPOSITE - Rigid Foam @ center
(max height = 7m)
RIBBED - max rib depth 305mm
(max height = 14m)
