Structural System Design

Flashcards on Structural System Components, Substructure, and Superstructure based on lecture notes.

System

An assembly of interrelated or interdependent parts forming a more complex and unified whole and serving a common purpose.

Structural System

A stable assembly of structural elements designed and constructed to support and transmit applied loads safely to the ground without exceeding the allowable stresses in the members.

Bulk-Active Structures

Redirect external forces primarily through the bulk and continuity of its materials, such as beams and columns.

Vector-Active Structures

Redirect external forces primarily through the composition of tension and compression members, such as a truss.

Surface-Active Structures

Redirect external forces primarily along the continuity of a surface, such as a plate or shell structure.

Form-Active Structures

Redirect external forces primarily through the form of its material, such as an arch or cable system.

Dead Loads

Weights of the various structural members and any permanently attached objects.

Live Loads

Loads that vary in magnitude and location, caused by temporary objects, moving vehicles, or natural forces.

Highway Bridge Loads

Loads due to traffic on bridge spans, with the heaviest loading caused by trucks.

Railroad Bridge Loads

Live loads applied on railroad bridges.

Impact Loads

The additional force imparted to a structure when moving vehicles bounce or sidesway.

Wind Loads

Pressure created by high wind speeds, proportional to the square of the wind speed.

Earthquake Loads

Lateral loadings produced on a structure through its interaction with the ground during an earthquake.

Hydrostatic and Soil Pressure

Pressure developed by water, soil, or granular materials against retaining structures.

Pin or Hinge Connection

Allows rotations but restricts any translations in any directions.

Roller Connection

Allows rotations but resist translation in a direction perpendicular into or away from its face.

Fixed/Moment Connection

Maintain the angular relationship between the joined elements, restrain rotation and translation in any direction, and provide both force and moment resistance.

Cable Connection

Allow rotation but resist translation only in the direction of the cable.

Structural Load Path

The route or path that forces (loads) take as they travel through a building or structure, from the point of application down to the foundation and ultimately into the ground.

Substructure

Lowest division of a building, constructed partly or wholly below ground, whose primary function is to support and anchor the superstructure and transmit its loads safely into the earth.

Shallow Foundations

Employed when stable soil of adequate bearing capacity occurs relatively near to the ground surface, transferring building loads directly to the supporting soil by vertical pressure.

Deep Foundations

Extend down through unsuitable soil to transfer building loads to a more appropriate bearing stratum of rock or dense sands and gravels well below the superstructure.

Spread/Isolated Footings

Supports an individual column and is circular, square, or rectangular slab of uniform thickness.

Strip/Wall Footings

Provided for a load-bearing wall or a row of columns which are so closely spaced that their spread footings overlap or nearly touch each other.

Combined Footings

Supports two columns and is used when the two columns are so close to each other that their individual footings would overlap.

Mat Foundations

A large slab supporting a number of columns and walls under the entire structure or a large part of the structure, required when the allowable soil pressure is low.

Strap Footings

Consists of two isolated footings connected with a structural strap or a lever, designed such that their combined line of action passes through the resultant of the total load.

Pile Footings

Long, slender columns driven deep into the ground, typically made of materials like steel, concrete, or wood, that transfer loads through skin friction or end bearing.

Drilled Shaft (Caissons) Footings

Large-diameter concrete cylinders drilled into the ground to support heavy loads, extending to bedrock or deep, stable soil layers.

Pier Footings

Use large columns that extend deep into the ground to transfer the building's load to strong soil or bedrock, often spaced apart under the structure to support concentrated loads.

Superstructure

The part of a building that is above ground level and plays a crucial role in transferring loads and maintaining the building's stability.

Columns

Vertical structural elements that carry loads primarily in compression, transferring the load from the beams and slabs above down to the foundation.

Slenderness Ratio

A measure of how tall a column is relative to its width. Slender columns may be more prone to buckling and require special design considerations.

Beams

Horizontal structural members that transfer loads from the slabs (floors) and walls to the columns, carrying mainly bending moments and shear forces.

Simply Supported Beams

Supported at both ends but free to rotate, making them efficient for shorter spans.

Continuous Beams

Extend over multiple supports, reducing bending moments in the middle of the span and leading to more efficient load distribution.

Slabs

Horizontal structural elements that form the floors and ceilings of buildings, distributing loads to the supporting beams and columns.

One Way Slab

Supported on two opposite sides and designed to span in one direction. Load is transferred primarily along the shorter span.

Two Way Slab

Supported on all four sides, distributing loads in two directions. This type is used when the slab's length and width are similar.

Walls

Provide both vertical and lateral support, serving as load-bearing elements that transfer loads to the foundation or as non-load-bearing elements that act as partitions.

Load-Bearing Walls

Support the structure above them, transferring loads from floors and roofs to the foundation.

Non-Load-Bearing Walls

Serve only as partitions to divide interior spaces and do not carry significant structural loads.

Bracing Systems

Essential for providing lateral stability in tall buildings and structures subject to dynamic forces such as wind or earthquakes, helping prevent excessive movement and structural damage.

Moment-Resisting Frames

Rigid connections between beams and columns that allow the frame to resist lateral loads through bending moments. These systems are used in high-rise buildings where large open spaces are needed without internal bracing.

Braced Frames

Resist loads through a series of trusses made of steel members. The diagonal members of the trusses resist lateral loads in the form of axial stresses, either by tension or compression.

Shear Walls

Provide lateral stability to the structure, especially in resisting wind or seismic forces. Often made of concrete or reinforced masonry and are strategically placed in the building to reduce deformation during lateral loading.

Tension

A pulling force that stretches a material, occurring when a structural element is subjected to forces that try to pull it apart along its length.

Compression

A pushing or squeezing force that compacts a material, occurring when structural elements are subjected to forces that push them inward, trying to shorten the element.

Shear Force

A sliding force that acts parallel to the cross-section of a material, occurring when layers of a material or different parts of a structure are pushed in opposite directions along a plane.

Bending

Occurs when a structural element is subjected to forces that cause it to curve or deflect, generating both tension and compression within the material.

Torsion

A twisting force that causes a structural element to rotate around its longitudinal axis, occurring when one end of the element is rotated relative to the other.

Factor of Safety

A design principle used to provide a safety margin beyond the calculated loads and stresses a structure might encounter, as a ratio between ultimate strength and design load.

Ductility

Refers to a material’s or structure’s ability to deform under stress without sudden failure, absorbing significant energy and undergoing large deformations before breaking.

Redundancy

Includes members, connections, or supports not required for a statically determinate structure so that if one member, connection, or support fails, others exist to provide alternative paths for the transfer of forces.

Continuity

Provides a direct, uninterrupted path for loads through a building’s structure, from the roof level down to the foundation.

System

An assembly of interrelated or interdependent parts forming a more complex and unified whole and serving a common purpose.

Structural System

A stable assembly of structural elements designed and constructed to support and transmit applied loads safely to the ground without exceeding the allowable stresses in the members.

Bulk-Active Structures

Redirect external forces primarily through the bulk and continuity of its materials, such as beams and columns.

Vector-Active Structures

Redirect external forces primarily through the composition of tension and compression members, such as a truss.

Surface-Active Structures

Redirect external forces primarily along the continuity of a surface, such as a plate or shell structure.

Form-Active Structures

Redirect external forces primarily through the form of its material, such as an arch or cable system.

Dead Loads

Weights of the various structural members and any permanently attached objects.

Live Loads

Loads that vary in magnitude and location, caused by temporary objects, moving vehicles, or natural forces.

Highway Bridge Loads

Loads due to traffic on bridge spans, with the heaviest loading caused by trucks.

Railroad Bridge Loads

Live loads applied on railroad bridges.

Impact Loads

The additional force imparted to a structure when moving vehicles bounce or sidesway.

Wind Loads

Pressure created by high wind speeds, proportional to the square of the wind speed.

Earthquake Loads

Lateral loadings produced on a structure through its interaction with the ground during an earthquake.

Hydrostatic and Soil Pressure

Pressure developed by water, soil, or granular materials against retaining structures.

Pin or Hinge Connection

Allows rotations but restricts any translations in any directions.

Roller Connection

Allows rotations but resist translation in a direction perpendicular into or away from its face.

Fixed/Moment Connection

Maintain the angular relationship between the joined elements, restrain rotation and translation in any direction, and provide both force and moment resistance.

Cable Connection

Allow rotation but resist translation only in the direction of the cable.

Structural Load Path

The route or path that forces (loads) take as they travel through a building or structure, from the point of application down to the foundation and ultimately into the ground.

Substructure

Lowest division of a building, constructed partly or wholly below ground, whose primary function is to support and anchor the superstructure and transmit its loads safely into the earth.

Shallow Foundations

Employed when stable soil of adequate bearing capacity occurs relatively near to the ground surface, transferring building loads directly to the supporting soil by vertical pressure.

Deep Foundations

Extend down through unsuitable soil to transfer building loads to a more appropriate bearing stratum of rock or dense sands and gravels well below the superstructure.

Spread/Isolated Footings

Supports an individual column and is circular, square, or rectangular slab of uniform thickness.

Strip/Wall Footings

Provided for a load-bearing wall or a row of columns which are so closely spaced that their spread footings overlap or nearly touch each other.

Combined Footings

Supports two columns and is used when the two columns are so close to each other that their individual footings would overlap.

Mat Foundations

A large slab supporting a number of columns and walls under the entire structure or a large part of the structure, required when the allowable soil pressure is low.

Strap Footings

Consists of two isolated footings connected with a structural strap or a lever, designed such that their combined line of action passes through the resultant of the total load.

Pile Footings

Long, slender columns driven deep into the ground, typically made of materials like steel, concrete, or wood, that transfer loads through skin friction or end bearing.

Drilled Shaft (Caissons) Footings

Large-diameter concrete cylinders drilled into the ground to support heavy loads, extending to bedrock or deep, stable soil layers.

Pier Footings

Use large columns that extend deep into the ground to transfer the building's load to strong soil or bedrock, often spaced apart under the structure to support concentrated loads.

Superstructure

The part of a building that is above ground level and plays a crucial role in transferring loads and maintaining the building's stability.

Columns

Vertical structural elements that carry loads primarily in compression, transferring the load from the beams and slabs above down to the foundation.

Slenderness Ratio

A measure of how tall a column is relative to its width. Slender columns may be more prone to buckling and require special design considerations.

Beams

Horizontal structural members that transfer loads from the slabs (floors) and walls to the columns, carrying mainly bending moments and shear forces.

Simply Supported Beams

Supported at both ends but free to rotate, making them efficient for shorter spans.

Continuous Beams

Extend over multiple supports, reducing bending moments in the middle of the span and leading to more efficient load distribution.

Slabs

Horizontal structural elements that form the floors and ceilings of buildings, distributing loads to the supporting beams and columns.

One Way Slab

Supported on two opposite sides and designed to span in one direction. Load is transferred primarily along the shorter span.

Two Way Slab

Supported on all four sides, distributing loads in two directions. This type is used when the slab's length and width are similar.

Walls

Provide both vertical and lateral support, serving as load-bearing elements that transfer loads to the foundation or as non-load-bearing elements that act as partitions.

Load-Bearing Walls

Support the structure above them, transferring loads from floors and roofs to the foundation.

Non-Load-Bearing Walls

Serve only as partitions to divide interior spaces and do not carry significant structural loads.

Bracing Systems

Essential for providing lateral stability in tall buildings and structures subject to dynamic forces such as wind or earthquakes, helping prevent excessive movement and structural damage.

Moment-Resisting Frames

Rigid connections between beams and columns that allow the frame to resist lateral loads through bending moments. These systems are used in high-rise buildings where large open spaces are needed without internal bracing.

Braced Frames

Resist loads through a series of trusses made of steel members. The diagonal members of the trusses resist lateral loads in the form of axial stresses, either by tension or compression.