ARCH 544 - Architectural Structures Midterms

Cement

The main binding component in concrete that reacts with water to form a hardened mass.

Fine Aggregate (Sand)

The fine aggregate commonly used to fill voids and improve workability of concrete.

Coarse Aggregate (Gravel/Crushed Stone)

The coarse material in concrete mix that provides bulk and strength.

Reinforcing Steel (Rebar)

The steel bars or mesh embedded in concrete to resist tensile stresses.

Admixture

The ingredient added to improve workability, durability, or setting time of concrete.

Water

The component that activates cement for hydration and affects workability and strength.

Concrete

A mixture of cement, water, fine and coarse aggregates that hardens over time.

Mortar

A combination of cement, sand, and water used to bond masonry units.

Paste

The mixture of cement and water before aggregates are added.

• Cement

• Fine Aggregate (Sand)

• Coarse Aggregate (Gravel/Crushed Stone)

• Reinforcing Steel (Rebar)

• Admixture

• Water

• Concrete

• Mortar

• Paste

CONCRETE MATERIALS & COMPONENTS

Workability

The property of fresh concrete that describes its ease of flow and placement.

Consistency

The stiffness or fluidity of fresh concrete.

Slump Test

The tool or test used to measure the consistency of fresh concrete.

Segregation

The separation of coarse aggregates from the cement paste due to poor mix or handling.

Bleeding

The upward movement of water to the surface of fresh concrete.

Setting Time

The time required for concrete to start and finish hardening.

Hydration

The chemical reaction between cement and water that causes concrete to harden.

• Workability

• Consistency

• Slump Test

• Segregation

• Bleeding

• Setting Time

• Hydration

FRESH CONCRETE PROPERTIES & TESTS

Tensile Stress

The type of stress that steel reinforcement is primarily used to resist.

Yield Strength (fy)

The stress at which reinforcing steel begins to yield.

Ductility

The ability of steel to deform without breaking.

Development Length

The minimum length of rebar required to achieve full bond with concrete.

Splice

The connection of two reinforcement bars to transfer force.

Concrete Cover

The concrete layer that protects reinforcement from corrosion and fire.

Bond/Composite Action

state when both concrete and steel deform together under load without slipping.

• Tensile Stress

• Yield Strength (fy)

• Ductility

• Development Length

• Splice

• Concrete Cover

• Bond/Composite Action

REINFORCEMENT & STEEL PROPERTIES

Compressive Stress

The type of stress concrete handles well due to its high compressive strength.

Tensile Stress

The stress that pulls materials apart and causes cracking in concrete.

Shear Stress

The stress that causes sliding forces within a structural member.

Bending Moment

The internal moment that causes a beam to bend.

Shear Force

The internal force that causes one section of a beam to slide past another.

Neutral Axis

The location in a bending member where stress is zero.

• Compressive Stress

• Tensile Stress

• Shear Stress

• Bending Moment

• Shear Force

• Neutral Axis

STRUCTURAL BEHAVIOR & STRESSES

Dead Load

The load from the structure's own weight, such as beams and slabs.

Live Load

The type of variable load caused by people, furniture, or moveable equipment.

Reaction

The total upward force provided by supports to resist applied loads.

Environmental Load

Loads from wind, earthquake, temperature, or rain.

Impact Load

A sudden or shock load applied in a short time.

Factored Load

A load multiplied by safety factors for design.

• Dead Load

• Live Load

• Reaction

• Environmental Load

• Impact Load

• Factored Load

LOADS & REACTIONS

Flexural Cracks

The initial cracking pattern in a concrete beam subjected to bending.

Compression Failure

The failure of a reinforced concrete column due to crushing of concrete under axial load.

Creep

The long-term deformation of concrete under sustained load.

Shrinkage

The decrease in volume of concrete due to drying.

Buckling

Sudden sideways failure of a column under compressive load.

Deflection

The vertical displacement of a structural member under load.

Shear Cracks

Diagonal cracks due to excessive shear forces.

• Flexural Cracks

• Compression Failure

• Creep

• Shrinkage

• Buckling

• Deflection

• Shear Cracks

FAILURE MODES & DEFORMATIONS

Typical Compressive Strength (𝒇𝒄′ )

The typical value of concrete compressive strength after 28 days (normal concrete).

Strength Design / Ultimate Strength Design / LRFD

The term for a design method that uses factored loads and strengths for safety.

Allowable Stress Design (ASD)

A method using working stresses lower than material strength.

Factor of Safety

A design margin to ensure safety against failure.

Balanced Condition

When concrete crushes and steel yields at the same time.

Under-Reinforced Section

Steel yields before concrete crushes (ductile and preferred).

Over-Reinforced Section

Concrete crushes before steel yields (brittle and unsafe).

Modular Ratio

The ratio of the modulus of elasticity of steel to concrete.

Stress Block

The idealized distribution of compressive stress in concrete.

Service Load

The actual load during normal use of the structure.

Ultimate Load

The maximum load a structure can carry before failure.

• Typical Compressive Strength (𝒇𝒄′ )

• Strength Design / Ultimate Strength Design / LRFD

• Allowable Stress Design (ASD)

• Factor of Safety

• Balanced Condition

• Under-Reinforced Section

• Over-Reinforced Section

• Modular Ratio

• Stress Block

• Service Load

• Ultimate Load

DESIGN CONCEPTS & METHODS