4 parts of a structure
Foundation
Vertical Walls
Horizontal Floors
Roof
3 degrees of a defect
- Is it a structural problem
- A problem that is in the process of failure
- Component has failed
Perhaps most importantly, the structure should safely support:
Live loads imposed on it
Out simply, the function of a structure is to:
Do nothing
What is a dead load?
The weight of the building materials and the soil surrounding the foundations
What are live loads?
People, furniture, snow, rain, wind
3 common configurations for foundations:
- Basements
- Crawlspaces
- Slab-on-grade
4 types of floor slabs:
- Floating
- Supported
- Monolithic
- Structural
Definition of floating floor:
Supported by the ground and independent of perimeter foundations
Definition of supported floor:
The floor slab may be integrated into the foundation system of the building (resting on the foundation)
Definition of a monolithic floor:
The floor slab may be an integral part of the footing
Definition of a structural floor:
Self-supporting or free spanning concrete slabs, either pre cast or cast in place
Definition of post-tensioned concrete slab:
One end of the cable is pulled tight after the concrete is poured
Definition of prestressed concrete slab:
Cables are pulled tight prior to pouring the concrete and are let go as the concrete cures
Definition of Spread Footings:
(Strip footings) Wide pads that are continuous around the perimeter of the house
Definition of a pilaster:
Thickening of a foundation wall
Definition of Pad Footing:
Usually under a single pier or column
Definition of End Bearing Piles:
Piles that are driven down to a point they meet bedrock or other sound substrate.
Definition of Friction Piles:
Piles that are driven down into soil far enough that the friction of the soil against the sides of the pile is enough to resist any downward movement.
Definition of grade beams:
Concrete beams that are supported on footings, piles, or piers and located at grade
Definition of Caissons:
Foundation systems created by drilling holes and filling them with concrete
3 factors that impact structural failures:
- Size of the load
- Direction of the load
- Time imposed
This is the most common problem found on all foundations:
Cracking
4 types of cracks:
- Shrinkage cracks
- Settlement cracks
- Heaving cracks
- Horizontal force cracks
What causes shrinkage cracks?
The natural curing of concrete
Shrinkage cracks usually show up when?
Within the 1st year
The most common foundation wall shrinkage cracks are:
Vertical or Diagonal
Foundation cracks most often radiate down from:
The corners of basement windows
Shrinkage cracks are relatively small, usually:
Less than 1/8 inch wide
Definition of Differential Settlement Cracks:
When one part of the house settles and the res does not, or 2 parts settle at different rates.
Definition of Uniform Settlement:
The structure settles slightly as a whole
Definition of Severe Uniform Settlement:
Uniform settlement that is so dramatic that gas, water, and electrical lines are strained and exterior sidings could come into contact with the soil
Definition of Tipping:
Leaning Tower of Pisa. When a building tips, one part of the building settles more than the other; however the building holds together and no cracks develop
Coarse soils that are wet have:
Little load bearing capacity change - Little foundation movement and moisture intrusion.
Fine soils that are wet have:
Large bearing capacity change - A larger risk of substantial foundation movement and moisture intrusion
Definition of Cut-and-Fill lots:
Creating a flat building pad by cutting back into the hill to form the pad on the uphill half of a house
What is the usual direction of cracks due to differential settlement?
Vertical or diagonal
What is usually an indicator of heaving rather than of shrinkage or rotation?
Crushing of material
Definition of Heaving:
Upward movement of a building
