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94 Cards in this Set
- Front
- Back
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Types of Wood |
- Hardwood: deciduous trees
- Softwood: conifers (primarily evergreens) - Misnomer: softwoods harder than hard woods - most lumber used for structural purposes in US are softwoods |
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Primary Species Used |
- Douglas Fir - Hemlock/Fir - Southern Pine - California Redwood - Eastern Spruce |
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Wood Introduction |
- human's oldest construction material - 90% of all houses in the US are wood |
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Wood Construction Uses |
- buildings (residential, commercial, industrial) - piers - bridges - retaining walls - power transmission lines |
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Bamboo (1/3) |
- Giant grass - can grow up to 4 feet per day - 1500 species - plant lasts 75 years and 3 to 6 years to reach maturity |
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Bamboo (2/3) |
- Timber Bamboo: largest bamboo - can grow up to 120 ft and 13 in. in diameter in 6 years - at least 2 times stronger than lumber - greater yield per acre |
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Bamboo (3/3) |
- tested to perform under compressive and tensile strengths comparable to traditional lumber - light weight means that it performs better in shear that are in play during high winds and seismic activity - LEED Credits: due to high level of renewal ability |
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Structural Wood |
- Lumber: any wood cut into a size and shape suitable for use as a building material - Timber: broadly classified as lumber having the smallest dimension of at least 5" - Structural Lumber - Surface Treatment |
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Structural Lumber |
- Board: lumber less than 2" thick and at least 2" wide - Dimension: lumber at least 2" thick and less than 5" wide -Beam and Stringer: lumber at least 5" thick and 8" wide - Post and Beam: approx. square and at least 5" wide |
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Surface Treatment |
- Rough sawn - Dressed |
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Wood Moisture Content |
- weight of wood/weight of oven dried wood - M.C. > 30%: wood essentially in natural state - M.C.< 30%: wood shrinks and strength prop. increase - Bending strength: strength of wood - greater for softwood is greater at lower M.C. |
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Oriented Strand Board (OSB) |
- cheaper than plywood ($3-$5 per board) - heavier and not as stiff as plywood - indoor use only (doesn't handle moisture well) - has over 70% market share for structural panels. |
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OSB vs Plywood: Constituents |
- OSB: rectangular shaped wood strands layered in specific orientation and combined with wax and resin - Plywood: thin sheets of veneer are glued together |
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OSB vs Plywood: Structure |
- OSB: outer layers aligned parallel to strength axis; inner layers are aligned perpendicular to the axis - Plywood: odd number of layers with grains adjacent layers at right angles to eachother and face veneers are higher grade than core veneers |
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OSB vs Plywood: Uses |
- OSB: roofs, walls, and subfloors - Plywoods: roofs, walls, subfloors, boxes, packages, sports equipment, musical equipment, playground equipment, high-end loud speakers |
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Platform Frame Construction |
-sistered joist |
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Wood Framing Construction - Hand Framed |
- jack - cripple - hip |
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Fastening, Connectors, Notching and Boring of Beams |
- Penny: nails |
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Mixing Sawn Lumber and Engineered Wood |
- Usually there is a significant difference in moisture content between sawn and engineering lumber - samn lumber newer the limit of 19% moisture - engineered wood: moisture around 5% - when placed in direct contact their moisture content will strive to reach equilibrium. Therefore, these materials should not be placed in direct contact; some barrier between them |
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Frame Construction (1/2) |
- Utilizes studs (typically spaced 16 or 24 in. on center), joists, and rafters to form the building frame. - framing members are usually 2 in. nominal thickness (2x4 - actual size 1.5x3.5) - frame is covered with siding and roof sheathing of plywood and lumber |
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Frame Construction (2/2) |
- Widely used in the US for: - Single-family residence - small multiple-family residences - offices - shops |
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Sub-Floor: Header Joist |
-Box Sill |
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Floor Joist Bracing |
- Provides lateral bracing and strength - distributes load across floor - reduces potential squeaks |
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Wood Framing Construction |
- Use posi-joist (UK) and sleepers - Exterior Wall Framing- uses window headers and top plates |
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Baloon Frame Construction |
- never stack materials on unbraced floor joists, roof rafters, and trusses - not utilized frequently today |
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Wood Foundation Construction (1/2) |
- uses lumber that is pressure infused with chemicals and resist infestation and decay - eliminates need to cast and cure concrete footings - allows construction in any weather by same crew that completes other wood framing - resist cracking and are easy to insulate and finish for additional interior living areas. |
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Wood Foundation Construction (2/2) |
- over 300,000 US homes have been constructed with wood foundation systems - first developed in the 1960s after developed treatments for woods |
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Glulam |
- Consists of glued laminated timber composed of layers of wood 2 in. or less in thickness and glued together to form a solid structure |
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Glulam: Advantages |
- Manufacture structural members of great size - Unique shapes and curves - dimensionally stable members - strength characteristics can be controlled by placing the proper material in the proper location of the laminated structural member - provide for a cost effective way to make structural members - use for large buildings: churches, auditoriums, shopping centers, sports arenas and bridges |
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Glulam: Disadvantages |
- shipping and damage |
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Glued Laminated Timber: Cross Laminated Timber |
- massive panels made by bonding dimensional lumber in perpendicular layers - can be up to 70 ft long, 10 ft wide, and 18 in. thick - used for the floor, wall, and roofing system - larger scale of glue laminated timber - Assembled at a factory and quickly installed on site |
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Cross Laminated Timber: Benefits |
- comes from renewable resource - smaller carbon footprint than concrete and steel - weigh less than concrete panels and reduce transportation cost - requires last foundation - fares well in seismic tests since it is lightweight and has more repletion and ductility than other materials |
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Cross Laminated Timber: Growing Interest |
- opened doors for high-rise construction using wood structural systems - doesn't have any production plants yes - panels must be imported making them less cost competitive |
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Roof Framed with Rafters and Ceiling Joists |
- Use collar beam, ridge board, and rafter |
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Laminated Veneer Lumber |
- aka parallel strand lumber - similar to plywood by ply's and grains are parallel to length - engineered studs |
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Particleboard |
- wood chips glued together with resin and formed into sheets |
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Stucco |
- used as stucco over APA panel sheathing - made of aggregates, binder (portland cement), and water - applied wet hardens to a very dense solid - used as decorative coating for walls and ceilings and as a sculptural and artistic material in architecture - can cover metal, concrete, cinder block, or clay brick and adobe |
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Common Wood Siding |
- Bevel - Drop - Board and Batten - Tongue and Groove |
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Timber Construction: Bowstring Roof Truss |
- aka barrel truss - supported by wood column |
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Wood Framing Construction: Sub-Floor |
- no notches in middle third of joist span - no holes closer than 2-in. from edge - max notch depth: 1/6 actual joist depth - max hole diameter: 1/3 actual joist depth - max notch width: 1/3 actual joist depth |
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Connecting Wood - Philosophy |
- wood likes compression parallel to grain - wood likes to take on load spread over its surface - avoid tension perpendicular to grain - wood, like other materials, moves in varying environments - fastener selection is key to connection ductility, strength, performance |
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Brick Masonry: Elements |
- header - stretcher - collar joint - wythe - vertical or head joint - course - horizontal or bed joint |
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Mortar Joint Finishes |
- flush - struck - weather - concave - vee - raked |
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Principal Brick Pattern Bonds |
- running bond - common bond - english bond - flemish bond - stack bond |
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Brick Walls |
- brick cavity wall - masonry bonded hollow wall |
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Brick Walls: Support Over Openings |
- jack arch - segmental arch - precast concrete lintel - reinforced brick masonry lintel |
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Horizontal Joint Reinforcement |
- tied wall - cavity wall - stack bond wall - running bond wall |
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Masonry Terms |
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Foundation Systems |
- structure supports the weight of the structure and its applied loads - includes soil or rock upon which a structure rests - structural system designed to transmit building loads to the supporting soil or rock |
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Pile Capacity |
- ultimate load capacity |
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Pile Types |
- timber - precast concrete - cast-in place - steel - composite - bulb |
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Timber Piles |
- Inexpensive - Easy to cut, splice, and handle - maximum pile length to tree height (100 ft) - load capacity is limited - ends may splinter in driving - subject to insect attack and decay |
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Precast Concrete Piles |
- manufactured to any shape or size - high strength - resistant top decay - heaviest and hardest to handle - brittleness requires care when driving - cutting is difficult |
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Cast-in Place Concrete Piling |
- Shell Pile - shells driven and then filled with concrete are easy to handle - shells are reinforcing and protection for the concrete - easy to cut and splice - continuous inspection required due to being damage prone |
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Steel Piles |
- can support very heavy loads - driven to very deep depths w/o damage - easily cut and spliced - H-piles and pipe are common shapes - H-piles can have harden tips for driving in tough material |
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Composite Piles |
- made of two or more different materials (timber lower and shell pile upper) - economical to use when the lower section would be submerged - not subject to decay |
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Bulb Piles |
- aka Franki Pile, Pressure Injected Footings Rammed Aggregate Pier (RAP) - Special form of cast in place - formed during driving - enlarged base in crease effectiveness - zero slump concrete utilized |
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Construction Applications of Concrete |
- portland cement concrete: one of the world's most versatile and widely used construction material - Other applications: - foundations for small structures, structural components, wall panels, massive concrete dams |
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Concrete Formwork Requirements |
- Safe - Produce desired shape and dimensions - economical |
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Typical Formwork Elements |
- Spaces for anchor bolt - Braces - Wale - Stud - Tie - Footing - Plywood or Board Sheathing |
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Concrete Construction: Placing and Consolidating |
- Consolidation: process of removing air voids in concrete as it is placed - accomplished by immersion type electric pneumatic or hydraulic actuated vibrators - vibrators should not be used to move concrete laterally - external or internal vibrators |
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Concrete Construction: Placing and Consolidating (Graph top to bottom) |
- Full consolidation: No entrapped air - Laboratory Consolidation: Little entrapped air (=1%) - Good Field Consolidation: 1%-2% entrapped air - Range of field-placed concrete with no consolidation: 5%-20% entrapped air |
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Consolidating |
- usually by vibration - increases concrete strength by driving out entrapped air - improves bond strength and decreases concrete permeability |
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Consolidation Affects Compressive Strength |
- results dramatically underscore the need for consolidation - compressive strength reduced by about 30% for each 5% decrease in degree of consolidation - poorly consolidated concretes were more permeable to chloride ions |
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Pumping Concrete |
-concrete pumped into bottom of column form - pump from bottom up to eliminate vibration limitation and honeycombing due to reinforcement - Form forces are +25% more than normal |
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Tilt-Up Construction |
- Concrete elements are formed horizontally on a concrete slabs - normally requires building floor as a building form - may be a temporary concrete casting surface near the building footprint - After curing, elements are tiled to vertical position with a crane and braced into position until the remaining building structural components are secured - Known for poor performance during earthquakes and seismic activity |
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Pre-Stressed Concrete |
- overcomes weakness in tension - used to produce beams, floors or bridges with a longer span - pre-stressing used to provide a clamping load producing a compressive stress that balances tensile stress experienced during bending |
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Pre-stressing Techniques |
- pre-tensioned concrete - bonded post-tensioned concrete - un-bonded post-tensioned concrete |
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Post Tensioned Concrete |
- Un-Bonded - Bonded |
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Factors Affecting Lateral Pressure on Concrete Formwork |
- Method of placing (pumping, tremie, dropping from chute or bucket) - rate of placement - consistency and proportions of the mix - temperature of the concrete - rate of initial set - effect of vibration (external or internal) - size and shape of form - wind |
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Rolled-Steel Section Shapes |
- W-Shape - S-Shape - HP-Shape - American Standard Channel (C) - Angle (L) |
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Field Connections: Fastening Systems |
- Bolted Connections - Welded Connections |
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Field Connections: Bolted Connections |
- Slip Critical Joint - Shear Joint |
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Bolted Connections: Faying Surface |
-surface of a metal or wooden member joined closely to another member in such a way as to leave no space between them |
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Bolted Connection: Slip-Critical Joint |
- relies on friction rather than bolt shear or bolt bearing to join structural elements - loads can be transferred between two structural elements by either a bearing-type connection or a slip-critical connection -loads transferred through friction forces between faying surfaces |
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Slip-Critical Joint-Friction Forces |
- Generated by the extreme tightness of structural bolts holding the connection together - usually tension control bolts or compressible washer tension indicating bolt type - load transferred by plate connections not by bolts - fail by slipping - would result in unitended ponding effects |
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Faying Surfaces |
- must be properly prepared to maximized friction forces - requires: - cleaning - roughening - descaling - blasting - painting with class B primer |
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Installation of Tension Control Bolts |
- Bolt installed finger tight - Installation tool tightens nut while holding spline - sheared spline drops off |
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Bolt Tightening Procedures |
- Turn of the nut method - Calibrated-wrench tightening - Installation of alternate design bolts - Direct-tension-indicator tightening |
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Rivited Connection |
-magnitude of clamping is function of length of rivet and magnitude of shrinkage after the head is formed - magnitude f slip depends on the extent to which rivet fills the hole |
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Structural Bolt Types |
- Unfinished: A307 - aka rough, common, ordinary, and machine - made of low carbon steel (tensile strength = 60ksi) - High Strength Bolt: A325, A449, A490) - A325: made of medium carbon steel whose tensile strength decreases with increase in diameter. - High strength bolts can be tightened to large tensions |
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Turn of the Nut Metod |
- only performed after all steel piles in a connection have been drawn into firm contact - failure will result in loose connections - performed by rotating the nut or bolt of a fastener assembly a specific turn angle based on the fastener's length - diameter while restraining the unturned element from rotating |
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Turn of Nut Method: Installation |
- Determine ratio between fastener's length and diameter as well as slope disposition of the outer steel piles - Apply the specified turn from the appropriate table, while the unturned element is restrained from rotation - rotation exceeding the table below may be corrected or reworked except by replacing the fastener assembly |
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Turn of Nut Method: Steps |
- "snug" tighten - mark nut and bolt - desired position achieved |
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Calibrated-Wrench Tightening Method (Torque Installation) |
- only performed after all steel plies in a connection have been drawn to snug-tightening -performed by applying calculated average torque value to fasteners - use of formulas or charts with specific values is not permitted |
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Tension Control Bolts |
- Insert Fastener - Apply TC Gun - Tension Nut - Remove Gun |
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Direct Tension Indicator Bolting (1/4) |
- little individual weigh scales that measure the bolt tension developed during tension developed during tightening, regardless of the torque resistance of the bolt - DTI are crushed to the point where a feeler gage cannot be inserted halfway around or to the point where DTI has squirted ouit silicone properly - completely independent of the torque resistance of the bolt assembly - compression of the DTI bumps can be seen by the eye and without a feeler gage |
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Direct Tension Indicator Bolting (2/4) |
-installers tend NOT to leave the bolts with insufficiently compressed DTI's - inspection by using a feeler gage can be done by anyone at any time when DTI's are used DTI is put on the nut end of the bolt so tightening can be done by one person because it is not necessary to hold the bolt roll |
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Direct Tension Indicator Bolting (3/4) |
- most common involve use of hollow bumps on one side of the water - bumps are flattened as the fastener is tightened -feeler gage: used to measure the gap developed by the bumps; when tight enough the feeler doesn't fit - newer types fill void under bumps with colored silicone |
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Direct Tension Indicator Bolting (4/4) |
- colored silicone squirts out once the bumps are compressed indicating proper tension - used in structural bolting industry for years and is now starting to carry over into other fields - can only indicate minimum tension required to close gap -washers can not indicate the amount of over tensioning - cannot monitor or display the amount of bolt relaxation |
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Castellated Beams |
- Aralevhastz - Araleghah |
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ASTM |
American Society of Testing and Materials |
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Principal Types of Structural Steel |
- A36 Carbon: Structural Steel (Fy=36ksi) - A572 High-Alloy Structural Steel (Fy=42-52 ksi) - A588 Corrosion-Resistant: High-Strength Low-Alloy Structural Steel (Fy=42-52 ksi) |
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Corrosion-Resistant High-Strength Low-Alloy Structural Steel |
Weathering Steel = Core-Ten Steel |
