Module 4 Footing & Foundation Inspection I part 2

1. ARC313 Building Code II Module 4Footing & Foundation Inspection I part 2

2. Review • What is the minimum bearing pressure allowed for soils to support foundations? • 75 kPa • How can you tell by looking at the excavation of a project if you may have questionable soil conditions? • garbage, discolouration, water

3. Review • If all soil conditions are adequate what table in part 9 gives you the minimum footing sizes? • Table 9.15.3.4 • What is the minimum thickness of a footing and what clause gives you that information? • 4” / 100 mm • 9.15.3.8. (1)(a) • Concrete with a high water to cement ratio is better than low water to cement ratio? • false, because it dilutes the mix

4. Suitable Materials The materials used in making concrete will influence: • workability, strength, durability, appearance and cost Materials that should not be used in the mix of concrete are: • shale, chert type aggregate • soft porous materials • dirty water

5. Adequate Curing • Effect of Moisture on the Strength of concrete

6. Adequate Curing • Effect of Temperature on the Strength of concrete

7. Failures in Concrete • Excessive Shrinkage causes • improper mix design • too much water in mix • inadequate curing • lack of protection • low humidity • high winds • high concrete temperature • low air temperature (freezing)

8. Failures in Concrete • Excessive Shrinkage remedies • using minimum amount of water • additives • super plasticizers • lower water amounts, but allow good workability • air entrainment • lower water amounts, but allow good workability • reduce segregation • avoid high concrete temperature • use larger aggregate • reduces amount of water • protect from sun, wind and rain • control joints in walls and slabs

9. Failures in Concrete • Cracking causes • overloading • backfilling • lack of lateral support • heavy equipment too close to the wall • shrinkage of the concrete • bearing of soil • freezing of fill material

10. Failures in Exterior Concrete Sidewalks, driveways, patios, garage slabs. Problems • shrinkage, cracking, movement / tilting, spalding / surface popping

11. Failures in Exterior Concrete Possible remedies • remedies from previous for shrinkage and cracking • compaction of material below concrete • saw cutting to allow concrete to crack at specific locations instead of randomly • incorporate reinforcing • steel reinforcing bars • W.W.M. (welded wire mesh) • adequate drainage to prevent frost heavage • proper concrete strength with 6 to 8% air-entrainment • avoid over finishing • keep moisture in concrete by misting, wet burlap • wetting granular fill before placement

12. Additives • super plasticizers • good for when pouring walls, using concrete pumps • allows the concrete to be placed with little movement, vibration • prevents excessive water bleeding and or segregation • CAUTION when using with other additives • hot water • used during cold weather to help prevent from freezing

13. Additives • calcium chloride / high early • helps to evaporate water from concrete • which helps during cold weather to prevent freezing • CAUTION when using with steel reinforcing will cause corrosion and possible surface cranking • cement types • see appendix A in back of your manual

14. Homework • Exercise #5, 6 & 7 • Pages 24 to 39