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78 Cards in this Set
- Front
- Back
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What is the approximate Span limit for a Waffle Slab
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Without Pre-stressing 40'
With Pre-strssing approx. 80' |
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what are the typical short direction spans for a one-way reinforced concrete slab
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10', 12', 14' 16'
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According to ACI 318 what is the minimum thickness of a one-way, simply-supported reinforced concrete slab with a span L
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L/20
h=thickness h=L(12in)/20 |
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According to ACI 318 what is the minimum thickness of a cantilevered reinforced concrete slab with a span L
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L/10
h=thickness h=L(12in)/10 |
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Aggregates generally represent what percentage of concrete volume?
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60%-75%
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Name the 5 concrete types.
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I - (General Purpose)
II - (Sulfate Resisting) III - (High Early Strength) IV - (Low heat of hydration) Type I and III are most commonly used type IV is no longer made |
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What is balanced steel ratio as applied to reinforced concrete?
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Reinforcement ratio that would result in a sumultaneous yield of steel and crush of concrete.
Max 75% Typically kept in the 40%-60% ratio for preliminary design. |
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Minimum thickness for concrete slab, residential
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4"
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According to ACI 318 what is the maximum spacing of the main reinforecment to resist bending moment?
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3 times the slab thickness or 18", whichever is smaller.
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Stirrups are placed to help resist...
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Shear.
The spacing and steel used depend on the grade of concrete. |
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what is the general distance of reinforcement bar spacing in a reinforced brick masonry wall?
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both vertical and horizontal bar are typically spaced 18" - 36"
Reinforced Brick walls are double wythe with approx a 2" grouted space between. |
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Generally what is the minimum safety factor to consider to resist sliding in a retaining wall?
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1.5
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Minimum thickness for concrete slab, residential
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4"
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According to ACI 318 what is the maximum spacing of the main reinforecment to resist bending moment?
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3 times the slab thickness or 18", whichever is smaller.
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Stirrups are placed to help resist...
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Shear.
The spacing and steel used depend on the grade of concrete. |
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what is the general distance of reinforcement bar spacing in a reinforced brick masonry wall?
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both vertical and horizontal bar are typically spaced 18" - 36"
Reinforced Brick walls are double wythe with approx a 2" grouted space between. |
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Generall what is the minimum safety factor to consider to resist sliding in a retaining wall?
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1.5
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Generally what is the minimum safety factor to consider to resist overturning in a retaining wall?
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2.0
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How do you find circumfrence
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C=2*pi*r
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A revolving cup anenometer measures...
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measures wind by measuring the time it takes a 1 mile column of air to pass by it.
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According to ASCE 7, when providing for accidental torsion, the mass at each level of building is assumed to be displaced in each direction a distance equal to...
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5% at that level perpendicular to the direction of force.
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To prevent deflection, building code limit the span to depth ratio of a plywood diaphragm to
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4:1
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The Saffir-Simpson scale classifies...
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Hurricane wind speed.
The 5 categories are 1 : 74-95 mph 2: 96-110 mph 3: 111-130 mph 4: 131-155 mph 5: >155 mph |
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Complex wind calculations and wind tunnel testing are required if buildings...
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Exceed 400'
buildings subject to dynamic effects buildings subject to wind vibrations buildings with a height to width ratio of 5 or more |
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Maximum drift of a building should be limited to...
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1/500 of buildings height
between stories drift should not eceed 0.0025 times the story height. |
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Gradient height is...
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The height at which ground friction and other obstructions no longer reduce wind speed.
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What is the strength reduction factor for spirally columns vs. tied columns?
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Spiral = .75
tied = .70 |
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What is the appoximate percentage of structural costs for different types of buildings?
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Commercial or Office = 25%
Buildings with minimal Architectural and mech. requirements such as warehouse and parking Garages = 50%+ Buidlings with complex Arch Mech req. such as Hospitals = 10%-15% |
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What are the maximum deflection limits for sawn wood members?
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L/360 for live load only and L/240 for live load plus dead load.
Ex. for a wood member spanning 22' Live Load only 22x12/360=.73" Live Load + Dead Load 22x12/240=1.1 |
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How to find the allowable load on a fillet weld...
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.707x(size of weld)x(Allowable Electrode Stress)
E60 = 18ksi E70 = 21ksi |
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At what angle of load to grain do wood fasteners have the greatest strength?
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The answer is 0 degrees. Wood fasteners are strongest when the load is parallel to the grain (0 to grain).
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What is bridging between joists used for?
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- To help reduce concentrated loads
- To provide lateral support |
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As a rule of thumb, the minumum distance between piles is
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3 diameters center to center
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The pressure exerted by retained earth against a retaining wall is called
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Active Pressure
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What is the formula for calculating the direct wind pressure on a vertical surface?
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P-psf = 0.00256v(sq)
ex. 0.00256 x 85 |
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wood I Joists can typically span...
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up to 45 feet
Generally used for distances over 20 feet |
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Characteristics of a Special Moment Resisting Frame (SMRF)...
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A Moment resisting frame that is specially detailed to provide ductile behavior.
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Characteristics of an Intermediate Moment Resisting Frame (IMRF)...
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Fewer restrictive requirements than a SMRF. Cannot be used in SDC D, E, or F however steel IMRF up to 35' can be used in D
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Characteristics of a Ordinary Moment Resisting Frame (OMRF)...
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Steel or concrete frame which does not meet the special detailing requirment for ductile behavior. Ordinary Steel frames can only be used in SDC A, B, C while Ordinary concrete frames can only be used in A or B
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In a dual system, the moment resisting frame must be capable of resisting at least ___% of base shear...
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25%
The 2 systems must be designed to resist the total lateral load in proportion to their rigidities |
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Moment of Inertia is a measure of the....
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Stiffness of a beam, that is, its resistance to deflection
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Section modulus is a measure of...
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bending or flexural strength of a beam
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modulus of elasticity determines...
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the stiffness of a material, or its resistance to deformation
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The maximum slenderness ratio permitted is...
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200
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What is the safety factor for flexure?
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1.67
Plastic Section Mod = M(1.67)/Fy |
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the roof live load for an ordinary flat, pitched, or curved roof before reduction...
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20 psf.
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In addition to the consideration of direct wind pressure on building surface, model building codes require consideration of...
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a roof uplift force of approx. 50-75% of lateral pressure.
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The code requires the use of a Strong Motion Accelerograph in...
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buildings in SDC D, E, F over 6 stores with aggregate floor area of 60,000sf or more and all buildings over 10 stories.
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Name the 5 vertical Structural Irregularities
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1a - Stiffeness Irregularity - Soft Story
1b - Stiffness Irregularity - Extreme Soft Story 2 - Weight Mass Irregularity 3 - Vertical Geometric Irregularity 4 - In-Plane Discontinuity in vertical lateral-force resisting elements 5 - Discontinuity in Capacity |
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Name the 5 Plan Structural Irregularities
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1a - Torsional Irregularity
1b - Extreme Torsional Irregularity 2 - Reentrant corners 3 - Diaphragm Discontinuity 4 - Out-of-Plane offsets 5 - Nonparallel systems |
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Vertical Structural Irregularity 1a
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Soft Story-
Lateral stiffness is less than 70% of the story above or less than 80% of average stiffness of 3 stories above. |
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Vertical Structural Irregularity 1b
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Extreme Soft Story -
Lateral Stiffness is less than 60% of that in the story above or less than 70% of average stiffness of the 3 stories above |
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Vertical Structural Irregularity 2
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Weight (mass) Irregularity -
Effective mass is more than 150% of the effective mass of an adjacent story. Roof that is lighter than the floor below need not be considered. |
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Vertical Structural Irregularity 3
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Vertical Geometric Irregularity -
Horizontal dimension of the lateral force resisting system in any story is more than 130% of that in an adjacent story. |
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Vertical Structural Irregularity 4
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In-Plane Discontinuity in vertical lateral force resisting elements -
An in plane offset of the lateral force resisting elements greater than the length of those elements or a reduction in stiffness of the resisting element in the story below. |
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Vertical Structural Irregularity 5
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Discontinuity in Capacity , Weak Story -
Lateral story strength is less than 80% of that in the story above. |
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Plan Structural Irregularity 1a
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Torsional Irregularity -
When max story drift, computed including accidental torsion, at one end transverse to an axis is more than 1.2 times the average of the story drifts at the 2 ends of the structure |
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Plan Structural Irregularity 1b
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Torsional Irregularity -
When max story drift, computed including accidental torsion, at one end transverse to an axis is more than 1.4 times the average of the story drifts at the 2 ends of the structure |
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Plan Structural Irregularity 2
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Reentrant Corners -
When both projections of a structure beyond a reentrant corner are greater than 15% of plan dimension of structure in the given direction |
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Plan Structural Irregularity 3
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Diaphragm Discontinuity -
Diaphragms with abrupt discontinuities or variations in stiffness, including those having cutout or open areas greater than 50% of the gross enclosed diaphragm area or changes in stiffness of more than 50% from one story to next |
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Plan Structural Irregularity 4
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Out of plane Offsets -
Discontinuities in path, such as staggered truss |
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Plan Structural Irregularity 5
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Non-Parallel systems -
Vertical Laterall force elements are not parallel to or symmetric about the major orthogonal axes of system |
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What is the minumum size of columns in heavy timber construction
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8x8
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What was the largest earthquake ever recorded?
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9.5
Chile 1960 |
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What was the magnitude of the 1906 San Francisco earthquake?
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8.3
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What was the magnitude of the 1933 Japan earthquake?
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8.9
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What was the magnitude of the 1995 Kobe Japan earthquake?
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6.9
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SDC A corepsponds to...
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Buildings in areas where ground shaking is minor
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SDC B corepsponds to...
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Buildings in Occupancy categories I, II, III where moderatly destructive ground shaking is expected.
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SDC C corepsponds to...
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Buildings in occupancy category IV, in areas where moderatly destructive ground shaking is expected, and buildings in occupancy I, II, III in areas where somewhat more severe ground shaking is expected.
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SDC D corepsponds to...
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Buildings in areas expected to experience severe and destructive ground shaking but not located close to a major fault line
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SDC E corepsponds to...
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Buildings of occupancy I, II, III in areas located near major active faults
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SDC F corepsponds to...
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Buildings of occupancy category IV near major active faults
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Name 2 buildings equipped with base isolators
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International terminal San Francisco Airport
Los Angeles City Hall |
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Name 2 buildings equipped with tuned mass dampers
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Citicorp bldg - NYC
Tapei 101 |
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What is the max depth/span for the 3 types of Open Web Joists?
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K = 30" depth 60' span
LH = 4' depth 96' span DLH = 6' depth 144' span (roof only) |
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What is the maximum spacing of lateral ties in a reinforced column?
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The lesser of the following
-16 times the diameter of the rebar -48 times the diameter of the lateral ties -the least dimension of the column |
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The minimum slab thickness for a cantilever slab is...
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L/10
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