Concrete Frame Structures Foundations

Concrete Frame Structures Foundations

• Foundations transmit building loads to the soil.
• Factors influencing foundation selection:
  • Ground conditions
  • Groundwater conditions
  • Site and surrounding buildings
  • Building structure requirements (safety, load-carrying capacity)
  • Constructional requirements (schedule, minimal resources, minimal cost)
• Foundation specialties include high cost and difficulty in repair. Often hidden underground, and a poorly constructed foundation can damage a building.
• Common mistakes: construction technology errors and inappropriate foundation types for the ground layers.

Types of Foundations

• Spread (Shallow) Foundations:
  • (Beam) Grillage Foundation:
  • Pad Foundation:
  • Mat Foundation (aka Raft Foundation):
    • A monolithic structure covering the entire building footprint (or larger).
    • Typically used for medium to high-rise buildings on soft soil.
    • Types include:
      • Solid Slab Raft
      • Beam & Slab Raft
      • Cellular (Void) Raft
• Balanced Foundation (aka Strap Foundation):
  • Two separate footings connected by a strap beam.
  • Used when one footing has limited space or soil bearing capacity varies.
  • Loads transferred between footings by cantilever action.
• Cantilever Foundation:
  • A footing extended beyond the support to transfer loads.
  • Used when limited space is available.

Foundation System Considerations and Applications

• Balanced and Cantilever Foundations: Used when footprint area is too small, or the boundary of the soil bearing capacity varies.
• Combined Footings: Can support two or more columns, but become uneconomical when columns are too far apart. A strap beam is used to connect them.

Types of Foundation System and Conditions

• Balanced Footings and Cantilever Footings: Used when a foundation doesn't have sufficient area to transfer loads safely, or there is a large difference in soil bearing capacity at the property line or the boundary.
• Cantilever footings: Used when a new building is constructed near an existing building and the existing building can't support the loads from the new structure.
• Cantilever Footings: Used when there's no possibility of digging near the foundations of nearby buildings. For example, if there's a chance that digging would cause a nearby building to collapse.

Explore the critical aspects of foundations in concrete frame structures. This quiz covers types of foundations, necessary considerations for foundation selection, and common construction mistakes. Understanding these elements is essential for ensuring the longevity and safety of your building project.