Engineering Loads on Buildings

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Questions and Answers

What are the two types of dynamic loads mentioned?

Pressure and Suction

Foundation Settlement and Wind

Wind and Earthquakes (correct)

Temperature and Moisture

How does wind affect a building during high wind intensities?

It causes horizontal movement of the building. (correct)

It creates static pressure on all walls.

It only affects the top parts of the building.

It has no effect on low buildings.

What primarily happens to a building during an earthquake?

The upper part remains stationary while the foundation moves. (correct)

All buildings collapse instantly.

The building experiences equal vertical and horizontal forces.

The foundation is completely unaffected.

Which component of an earthquake's motion is considered relatively harmless?

Vertical component Signup and view all the answers

What are equivalent loads primarily caused by?

Temperature changes and foundation settlement Signup and view all the answers

What is the effect of wind on a flat roof of a building?

Both pressure and suction occur. Signup and view all the answers

Which material is generally not affected by changes in humidity?

Metals Signup and view all the answers

Why are wind loads particularly crucial for tall buildings?

They can be pushed over by wind pressure. Signup and view all the answers

What defines a Dead Load in a building?

The weight of the structural components of the building Signup and view all the answers

Which statement is true about Live Loads?

They include the weight of furniture, equipment, and occupants. Signup and view all the answers

What is a significant challenge in estimating Live Loads?

Accurate weight measurements of all items in the building is impractical. Signup and view all the answers

How do building codes assist in determining Live Loads?

By offering standard assumed loads for various types of occupancy. Signup and view all the answers

In what scenario might Live Loads on a building increase significantly?

When heavy snow accumulates on the roof. Signup and view all the answers

Which type of load may be defined as stationery?

Static Loads Signup and view all the answers

Which factor complicates the assessment of Live Loads in certain buildings?

The movement of people within the structure. Signup and view all the answers

What are some examples of spaces where specific Live Loads are defined?

Normal office buildings and hospital wards. Signup and view all the answers

What is the primary purpose of providing expansion joints in long walls and floors?

To allow for expansion and contraction due to temperature and moisture movement Signup and view all the answers

What type of loads act vertically on a structure?

Live loads Signup and view all the answers

How can uneven settlement of foundations affect a building?

It creates stresses leading to cracks in the materials Signup and view all the answers

Which solution is NOT a method for providing lateral stability in a structure?

Use of flexible joints Signup and view all the answers

What is referred to as the path that a load takes through structural members to the ground?

Loadpath Signup and view all the answers

Which type of load is resolved into horizontal and vertical components for analysis?

Wind forces Signup and view all the answers

What phenomenon can cause bricks and concrete to crack over time?

Temperature and moisture movement Signup and view all the answers

What is the effect of forces on materials primarily governed by?

The bonds between atoms of which solids are composed Signup and view all the answers

What defines elastic deformation in a material?

Recovery of original shape when the force is removed Signup and view all the answers

How is stress calculated in a material?

Total force on a member divided by the area carrying the force Signup and view all the answers

Which of the following correctly describes strain?

It is a ratio of deformation to the original dimension Signup and view all the answers

What does Hooke's Law state about the relationship between stress and strain?

The ratio of stress to strain equals Young’s Modulus Signup and view all the answers

What occurs when the capacity for elastic deformation is exceeded?

The atomic bonds break, leading to failure Signup and view all the answers

Which materials are typically categorized as brittle?

Natural stone, brick, and concrete Signup and view all the answers

What is a key characteristic of ductile materials when subjected to stress?

They deform plastically, experiencing permanent changes Signup and view all the answers

Which statement is false regarding Young’s Modulus?

It is higher for ductile materials than for brittle materials Signup and view all the answers

What characterizes ductile materials compared to brittle materials?

Ductile materials can undergo large plastic deformations before rupture. Signup and view all the answers

What is the Elastic Limit in a material's behavior?

The limit beyond which the material will not return to its original shape after force removal. Signup and view all the answers

What is the main cause of buckling failure in vertical members?

High compressive stresses causing sideways deformation. Signup and view all the answers

How does increasing carbon content in steel affect its properties?

It reduces ductility. Signup and view all the answers

Which property is particularly true for brittle materials regarding tensile and compressive strength?

Their tensile strength is much lower than their compressive strength. Signup and view all the answers

What occurs at the Yield Point of a material?

It experiences large deformation with minimal additional stress. Signup and view all the answers

What factor contributes to the likelihood of bending in members?

Long and thin members. Signup and view all the answers

Which of the following statements about material failure is true?

Brittle materials exhibit elastic behaviour until they suddenly break. Signup and view all the answers

Study Notes

Loads Acting on a Building

Loads are categorized into Static and Dynamic.
Static loads are further categorized as Dead Loads and Live Loads.
Dead Loads are stationary and include the weight of the building structure itself.
Live Loads are dynamic and include occupants, furniture, and equipment.
Building codes dictate the loads to be considered for different types of occupancies.
This information comes from surveys of representative buildings to determine typical weight of furnishings and people.

Dynamic Loads

Wind loads are a significant factor for buildings of all sizes.
They include both pressure and suction.
Wind pressure acts on the windward side of the building and suction occurs on the other sides and roof.
Wind loads are particularly important for tall buildings due to their cantilever effect.
Wind velocity is not constant, resulting in dynamic effects that need to be accounted for.
Earthquakes are another type of dynamic load.
They are sudden, jerky movements of the ground.
The horizontal component of an earthquake can be particularly damaging.
Local building codes define the anticipated earthquake intensity.

Equivalent Loads

Result from temperature changes, moisture content fluctuations, and foundation settlement.
Expansion joints are used to accommodate changes in size due to temperature and moisture.
Uneven foundation settlement can induce stress in a building's superstructure.

Transmission of Loads

Loads transfer vertically and horizontally towards the ground.
The pathway of a load through structural members is known as the load path.
Vertical load paths are handled through compression, tension, or bending.
Horizontal load paths require lateral stability.
There are three methods for providing lateral stability:
- Triangulation
- Shear panels or walls
- Rigid frames

Effect of Forces on Materials

Solid materials are held together by atomic bonds.
These bonds can be extended or compressed, resulting in Elastic Deformation.
As long as the bonds are not broken, the material recovers its original shape after force is removed.
Stress is the force exerted on a material - calculated by dividing total force by the carrying area.
Strain is the deformation of a material due to stress, expressed as a ratio of deformation to original dimension.
The relationship between stress and strain is defined by Hooke's Law.
The Young's Modulus of Elasticity is a constant for different materials.

Failure of Materials

Beyond the Elastic Limit, atomic bonds start to break.
This results in either Plastic/Ductile failure or Brittle failure.
Ductile materials deform permanently before failure, allowing for some warning time.
Brittle materials fail suddenly with little deformation.
Buckling failure affects vertical members like columns and is caused by high compressive stress.
Buckling leads to sideways bending due to compression.
The bending causes further offset, increasing the bending moment until failure.
Longer and thinner members tend to buckle easier than shorter and thicker members.

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Description

This quiz covers the categorization of loads acting on buildings, including static and dynamic types. It explains the significance of dead and live loads, as well as the effects of wind and earthquake loads on structural integrity. Understanding these concepts is essential for civil engineering and architecture students.