Reviewer 6 Flashcards
What materials have adhesive and cohesive properties necessary to bond inert aggregates into a solid mass o adequate strength and durability
Admixtures Adhering Materials Inorganic Materials Cementitious Materials None of the Above
Cementitious Materials
What is generated when compounds in cement react with water to acquire stable low energy states?
Heat of Hydration
What compound reduce the interparticle forces that exist between cement grains in the fresh paste; thereby increasing the paste fluidity
Plasticizers
In mixes exposed to water, what is the term used to refer to the separation of aggregate from the bitumen due to the faster absorption of water on the aggregate surface?
Slippage
A parameter used for estimating strength of concrete
Water cement ratio
It is the property of fresh concrete which is the ability to flow under momentum transfer or under mechanical stress
Mobility
Placeability
True or False. As water to cement ratio increases, there is progressive weakening due to increase in porosity.
True
It is a temporary dam-like structure constructed around an excavation to exclude water
Cofferdam
Which of the following is not a property of hardened hydraulic cement concrete
Workability
Which of the following properties of aggregates has the least influence tp the quality of concrete?
Color, texture, and shape of its aggregates
Which of the following will minimize the cracking of pavement due to thermal expansion?
Compaction of subgrade
Provide Expansion Joints and sectional pouring of concrete
Consistency of concrete mixed
Provide expansion joints and sectional pouring of concrete
What is the mode of failure for short columns at which the concrete reaches its limits strain Eu at precisely the same instant that the tensile steel on the far side of the column reaches yield strain Ey
Balanced Condition
Given:
Es = 29, 000 ksi
Econcrete = 6, 000 ksi
What is the modular ratio?
4.83
just divide Es / Econcrete
What is the max Vs (shear carried by the stirrups)
2/3 sqrt( f’c)
What is the distance from the extreme fiver in compression to the centroid of the tension steel area
Effective Depth
The maximum usable strain at the extreme concrete compression fiver shall be assumed to be equal to ___
0.003
A burried plate, wall, or block attached at some distance from and forming an anchorage for retaining wall
anchor plate
It is a beam especially provided over an opening for a door, window, etch. to carry the wall over the opening
Lintel beam
What will happen to the concrete strength if the water to cement ratio decreases?
Concrete strength increases, porosity decreases, solid-to-space ratio increases
What is the property of concrete by which it continuous to deform with time under sustained loads at unit stresses within acceptable elastic range?
Creep
Honeycomb structures exhibit
small arches with chain particles
has a void ratio of 0.91 for a simple cubic packing
has a void ratio of 0.35 for pyramidal packing
Negative relative densities
What is the condition where the tension steel strain reaches the yielding strain simultaneously with the concrete reaching the crushing strain which is usually 0.003?
Balanced strain
What is a material that has adhesive and cohesive properties enabling it to bound mineral fragments into a solid mass in the presence of water?
Hydraulic cement
The ability of the soil to allow water to flow through it
Permeability
What is temporary force exerted by a device that introduce tension into a stressing tendons?
Lacking force
The distance between two structural supports is called?
Span length
The force adhesion per unit area of contact between two bonded surfaces is
Bond stress
A type of concrete floor which has no supporting beams
One way slab
A type of column that is not aligned to a lower floor column
Floating column
The degree to which a location is subjected to earthquake
Seismicity
Ties are used for what type of structural elements
Columns
HOneycomb concrete can be limited by the …
Use of concrete (cement?)
What is the purpose of the stirrups used from resisting vertical and diagonal tensions in a beam?
Hold bars in place
Structural member that is subjected to transverse load
Beam
Reinforcing vars put in contact to act as a ___ is called
Bundled bars
What usually happen to reinforcing steel bars in reinforced concrete of a beam if its members is about to collapse
Yield
Usual failure of a long column
Buckling
Allowable deflection for any structural member loaded with deadload and live load only
L/240
Spacing for lateral support of a beam shall not exceed ___ times the least width of compression flange of face
50
It is an isolated column of masonry of a bearing wall not bonded at the sides into associated masonry, when its horizontal dimension measured the right angles or the thickness does not exceed four times its thickness
pier
Method of pre stressing in which tendons are tensioned after concrete has hardened
post tensioning
A material, other than aggregate, cementitious material or water, added in small quantities to the mix in order to produce some (desired) modifications, wither to the properties of the mix or of the hardened product
admixture
SImply supported beam, L meters long, carrying a uniformly distributed load with N/m produces a shear force of ___
wL/2
Structures that are subjected to transverse loads are called ___
beams
These are referred to permanent loads or unmovable loads
Dead load
Loads that change position within the span of a beam in short amount of time. These loads are often exemplified by wheel loads
Moving loads
It is synonym to bending stress
Flexural stress
The minimum reinforcing steel for spiral columns allowed by the ACI code is
6-16mm diameter bars
The aCI codes states that bars larger that #11 should not be bundled in beams or girders. This means that one should not bunle the steel bars if the diameter is larger than:
36mm
The steel ratio, p for spiral columns ranges from ___
0.01 - 0.08
The temperature bars are 10 mm diameter steel bars placed on top and perpendicular to the main reinforcement of
One way slabs
Which is the correct factored load for strength Design Method
1.4 DL + 1.7 LL
It is defined as the unit strength of a material
Stress
The stress developed when the applied load causes adjacent sections within a body to slide past each other
Shearing stress
It is the contact pressure developed between two bodies
Bearing stress
The stress induced as a result of restrained deformations due to changes in temperature
thermal stress
The actual stress in a material under a given loading
Working stress
It is the maximum safe stress that a material can withstand
Allowable stress
A mixture of water, cement, sand, gravel or other aggregates
Concrete
The nominal maximum sizes of course aggregates should be greater than ___ the narrow dimension between sides of forms, ___ the depth of slabs or the ___ minimum clear spacing between individual reinforcing bars
> 0.85
the narrow dimension between sides of forms,
1/3
the depth of slabs
3/4
minimum clear spacing between individual reinforcing bars
The shortest length in meters of a commercially available rebar
6m
Aggregates that passes through a No. 4 sieve ( about 6mm in size )
fine aggregates
The nominal diameter of a #8 rebar in mm
25mm
It is the 28th day compressive strength of concrete
Fc’
The maximum number of rebar in a bundled bar
4
The longest length in meters of a commercially available rebar
12
The load factor for a dead load
1.2
The load factor for a live load
1.6
The load factor for wind load
0.8
A composite member consisting of a concrete and reinforcing bars
reinforced concrete
The strength reduction factor for flexure is___
0.9
The nominal diameter factor of #3 rebar in mm
10
It is the yield strength of steel rebar
Fy
The maximum usable strain for concrete is
0.003
Aggregates that are retained through a No. 4 sieve (about 6mm in size)
coarse aggregates
Code limits the tensile steel percentage to ensure what kind of failure?
Brittle
What is the standard weight in kilograms of one bag Portland cement?
40kgs
The value of Beta1if the fc’ is less than 30MPa
0.85
The maximum reinforcement ratio provided by the code is taken __ / fy
1.4
True or False. Water coming from clear canals can be mixed concrete
F
True or False. Reinforcing steel is strong in tension
T
The higher the water cement ratio, the lower the strength of the concrete
T
Deformed rebar is better than plain rebar
T
Tables and chairs inside a classroom is considered Dead load
F
Elongated gravel is much better than rounded gravel
F
Under reinforced design is more preferred by designers other than the over reinforced design
T
A slump of zero mean high workability
F
Concrete is strong in compression
T
Live load for classrooms are larger than that of the libraries
F
The maximum moment of a simply supported beam whose span is L in meter carrying a uniformly distributed load of w in N/m is ___
wL2/8
Loads that are movable or replaceable on structure are known as
Live load
It is one in which the lateral stiffness is less than 70% of the stiffness of the story above it
Soft story
Horizontal or nearly horizontal system acting to transmit lateral forces of the vertical resisting elements. It includes bracing systems
Diaphragm
These are inert material used in concrete which occupy more than 75% of the volume of the hardened concrete product
Aggregates
Steel elements such as wire, cables, bars, rods or strands of wires or a bundle of such elements used in pre-stressed concrete structures are called ___
Tendons
What method of pre-stressing in which tendons are tensioned before concrete is cast in place
Pre tensioning
This refers to the substance other than aggregate, cement or water added in small quantity normally less than 5% of the weight cement, to alter the properties of the concrete mix or the hardened solid
Admixture
The minimum bend diameter for 10mm dia through 25mm dia bars
6db
Bars larger than ___mm shall not ve bundled in beams
36mm
Minimum concrete cover cast against and permanently exposed to earth
75mm
In ultimate strength design, the strength reduction factor dia for shear and torsion
0.85
The minimum one way slab thickness for a both ends continuous slab is
L/28
Deep simple span flexural members has overall depth to clear span ration greater than
0.6
Before commencing the excavation work, the person making the excavation shall notify in writing the owner of the adjoining building not less than __days before such excavation is to be made
10days
The maximum spacing of ties and spirals driven in a driven precast concrete pile center to center
150mm
Aviation control towers fall to what type of occupancy
Essential Facilities
The allowable deflection for any structural member loaded with live load only
L/360
A wall that resists horizontal forces applied in the plane of the wall
Shear wall
Adherence between materials such as bricks/mortar, or piles of felt, of between felts and other elements of roof systems which use bitumen or other materials as the cementing agent
Bond
If the ratio of the short direction to the long direction of a slb is less htan 0.5 then the slab is considered __
one way slab
In ultimate strength design, the reduction factor diameter for bending is __
0.9
The actual strain by which a concrete is 0.004. For safety purposes the ACI code allows designers to use
0.003
The minimum clear cover allowed by the code for slabs, not exposed to weather is
20mm
8 steel reinforcing bar diameter in mm
25mm
What do you call structures that are necessary for emergency operations subsequent to a natural disaster
essential facilities
It is one in which the lateral stiffness is less than 70% of the stiffness of the story above or less than 80% of the average stiffness of the three stories above
soft story
The structural system without a complete vertical load carrying space frame
bearing wall system
Large beam supporting a smaller beam
Girder beam
Advantage of steel over concrete
Elasticity
Material added to modify cement properties
Admixture
Artificial stone derived from mixture of properly proportioned amount of hydraulic cement, fine aggregates, coarse aggregates and water with or without admixtures
concrete
Secondary effect on shears, axial forces and moments of frame members dues to the action of the verical induced by horizontal displacement of the structure resulting from various loading
Aftershock
It is one in which the story strength is less than 80% of the story above
Weak story
Wall design to resist the lateral displacement of soil or other materials
Retaining wall
Occupancies and structures housing or supporting toxix or explosive chemicals or substances. Non building structures storing, supporting or containing quantities of toxic or explosive substances
Hazarduous facilities
It is an assemblage of framing members designed to support gravity loads and resist lateral forces
Structure
Minimum clear cover for beams, not exposed to weather i __
40mm
