Forging new generations of engineers

1. Forging new generations of engineers

2. FOUNDATION DESIGN

3. Foundation- Design Considerations Factors to be taken into consideration when determining the type of the building foundations: • Function of the structure • Loads from the structure • Bearing capacity of foundation material • Total and differential settlement of foundation • Uplift forces acting on the foundation • Costs

4. Soil Bearing Capacity The soil bearing capacity needs to be determined. This can be done by: • Local or State Building Codes • Uniform Building Code (UBC) • Soil testing/analysis • Site inspection and simple soil testing • Soil borings taken at proposed foundation locations

5. Foundations- Shallow • Shallow Footings- in Rochester, NY the base of the footing must be 48” below ground surface. • Spread footing ( square or rectangular)- footing is spread out over a broad area. Usually in low-rise buildings • Strip Footing – with load bearing walls, an example would be basement walls, in which the building loads are carried by the foundation walls with continuous footings. • Grade Beams - as the name implies , these are beams at grade. It may be built integral with the floor slab or may be used for Pile caps.

6. Foundations - Deep • Pile Foundations - vertical structural members that are forced into the ground by pile drivers (similar to driving nails into wood) • Caissons – similar to pile foundations, but are created by auguring (drilling ) a deep hole into the ground and then filling the hole with concrete. Caissons may be belled at the base. Steel reinforcement may also be used. Caissons can extend to bedrock.

7. Foundations • Mat or raft foundations – the entire building is placed on one large continuous footing. Typically used in locations where the soil is weak/poor and bedrock is too deep. • Mat foundations with caissons or piles – a combination of a mat foundation with piles or caissons.

8. W=footing width Diminishing Soil Pressure Critical zone for compaction Soil pressure cut by ½ at this level W Soil pressure cut by 2/3 at this level W Soil Bearing Pressure Spread Footings Calculated Soil Bearing = Load (pounds) Area of Footing (sq.ft) Compare to Allowable Soil Bearing Capacity

9. Building Type Guide • Short Span Buildings • 10 to 40 feet bays • Flexible plan • Structural elements (columns) can determine spatial relationships • Moderate Long-Span Buildings • 40 to 140 feet bays • Need to consider structural depth of floor and roof in the spatial planning

10. Building Type • Long-Span Buildings (> 150 feet ) • Structural system determines the building's image or visual statement

11. Reference Sources • Jefferis, A., & Madsen, D. A. (2001). Architectural Drafting and Design. Albany, NY: Delmar, a division of Thomson Learning. • Kane, K., & Onouye, B., (2002). Statics and Strength of Materials for Architecture and Building Construction.(2nd ed.). Saddle River, NJ: Pearson Education, Inc • Shaeffer, R. E., (2002). Elementary Structures for Architects and Builders (4th ed.). Columbus, OH: Prentice Hall. • http://www.concretenetwork.com/concrete/footing_fundamentals/why_soils_matter.htm • http://www.emporis.com/en/ • http://www.pbs.org/wgbh/buildingbig/lab/forces.html