TERMS: Architectural Structures

One-way Slab

A slab that transfers load mainly in one direction.

Clear Span

The distance measured from face to face of supports.

Effective Span

The design span used in slab calculations.

Effective Depth

Distance from compression face to the center of tension steel.

Main Reinforcement

Steel bars placed parallel to the shorter span of a slab.

Distribution Reinforcement

Steel bars provided perpendicular to main bars to resist temperature and shrinkage.

Span-to-depth Ratio

Ratio used to control deflection in slab design.

Deflection

The vertical displacement of a slab due to loading.

Axially Loaded Column

A column subjected to load applied along its longitudinal axis.

Slenderness Ratio

The ratio of effective length of a column to its radius of gyration.

Effective Length

The length of column based on end support conditions used in design.

Buckling

Mode of failure of slender columns due to instability.

Short Column

A column that fails mainly by crushing rather than buckling.

Ties

Lateral reinforcement in rectangular columns used to hold main bars in position.

Spirals

Continuous helical reinforcement used in circular columns

Gross Area

Total cross-sectional area of a column including concrete and steel.

Axial Load Capacity

Maximum vertical load a column can safely carry.

Longitudinal Reinforcement

Vertical steel bars that resist axial forces in a column.

Pure Axial Column

A column designed to carry only axial load without bending.

Confinement

The effect of lateral reinforcement in improving column strength and ductility.

Factored load

Design load obtained after applying load factors to service loads.

Flexural reinforcement

Tensile steel provided to resist bending in slabs and beams.

Shear reinforcement

Reinforcement provided to resist diagonal tension failure.

Concrete cover

Protective layer of concrete between reinforcement and the surface.

Bar spacing

Minimum distance provided between parallel reinforcing bars.

Dead load

Permanent load from the self-weight of the structure and attached elements.

Live load

Temporary load due to occupants, furniture, or movable objects.

Width of slab (b)

The width of the slab used in flexural design calculations.

Ultimate strength design

Method of design based on ultimate (failure) strength of members.

Serviceability

Ability of a structural member to perform satisfactorily under service loads without excessive deflection or cracking.

Cracking moment

Moment at which the first visible crack appears in a concrete member.

Balanced section

The condition where steel yields at the same time concrete reaches its crushing strain.

Axial compression

Load acting along the longitudinal axis of a column.

Load combination

Set of combined loads used for structural design safety.

Concrete compressive strength(f’c)

Property representing the crushing strength of concrete.

Yield strength of steel (fy)

Stress level at which reinforcing steel starts to yield.

Interaction diagram

Relationship showing combined axial load and bending moment capacity of a

column.

Effective length factor (K)

Factor used to modify the unsupported length of a column based on end conditions.

Minimum eccentricity

Minimum bending moment assumed in column design due to imperfection of load application.

Stress–strain relationship

Graph showing the relationship between stress and strain of a material.