Module 4 Footing & Foundation Inspection I

ARC313 Building Code II Module 4Footing & Foundation Inspection I

Review • What does volume 2 of the OBC help you with? • specifics as to assemblies for different materials, visual details for some assemblies and more detailed / clarifications of different parts of the code • help designers with fire separations, assembly information, load calculation information

Review • What is the code requirement for excavation, in regards to freezing and what clause is it? • the bottom of excavations shall be kept from freezing throughout the entire construction period • 9.12.1.3.(1)

Review • Can a foundation be placed on organic material and what clause is it? • NO, the bottom of every excavation shall be free of all organic material • 9.12.1.1.(3) • What is angle of repose? • angle of repose is the steepest angle which the surface of a mass of loose material makes with the ground

Review • If your foundation is below the footing of an adjacent building what must be done and what division and clause gives you that information? • the foundations shall be designed by a professional engineer • Division C – 1.2.1.1.(5)

Review • What are 4 requirements that must be taken in consideration when it comes to excavation for a foundation? • minimum depths of foundations • water on site • soil type • freezing conditions

Module 3 exercise #3M3:1

Footing & Foundation Inspection I Soil Conditions • soil type maps are available to engineers for design calculation purposes • stiff clay ( Windsor area ) has a bearing pressure of 150 kPa or 3130 psf • see 9.15.1.1 for minimum soils bearing capacity

Soil types in Essex County

Bore hole

Soil Conditions • see 9.4.4.1 table for allowable bearing pressure for soil or rock • when buildings are going to be built on soil condition that do not meet minimum bearing capacity (75 kPa), Division B, Part 4.2.4 Design Requirements applies • if angle of repose for soil becomes a concern, Division C, Part 1.2.1.1(5) applies

Questionable soils 9.4.4.1.(3) (c) • Caution when excavating and the following is observed: • cans, tires, construction materials are exposed • soil discolouration • water that occurs when there has been no rainfall • If the above is observed a geotechnical expert should be retained to: • verify of adequacy of the particular design • report actual bearing capacity of the soil • confirm location of water table at the site

Plain Concrete Footings • Part 9 allows the design of footings to be un-reinforced concrete in such a way that shear reinforcing will not be required which simplifies the process of building footings • Minimum 100mm (4”) by code • CAN/CSA-A23.3-04 200mm (8”) • Division A 1.5.1.2.(1) says that if there is conflict between standards that, the building code prevails

General Qualities of Concrete • The higher the strength does not mean it is good concrete. • A concrete that will last over time and resist wear has to have: • good quality aggregate • optimum amount of Portland cement • minimum amount of water • +/- 6% air entrainment

Concrete mix design should have • acceptable workability • strength • durability • good appearance • economy/cost (see Figure M4:1) • Factors that contribute to good quality concrete • low water to cement ratio (see figure M4:2) • air entrainment • quality materials • adequate curing • good construction practices

Concrete mix design • Concrete with too much water will be: • porous • weak • shrink more • segregate and honeycomb • poor appearance • prone to water leakage • not economical See figure M4:3

Module 4 Footing & Foundation Inspection I