Let’s talk about how to on foundation
You get a lot of different foundation types. For example, strip foundation, rafter or float foundation, pad or isolated foundation, then ground beams with column foundation. Then there is also pile foundation an even underpinning. Each of these foundations will be use for a specific reason. It all depend on the soil conditions. You get top soil, sub soil, sandy soil, clay soil, filled ground swampy soil and then also rock ground.
Each of these different foundation types will be use on a specific soil that will keep the building up. It all depend on the load of the building. You get shallow foundation that is normally less than 1.5m beneath ground level, or you get a deep foundation that is normally more than 3m below ground level. You can not just go and through some crusher, river sand, cement and water together and hope it will be fine. There are a lot of different properties to concrete. You need to know what mix is required, what the strength of the concrete should be. It’s also about the consistency of the concrete and also about the hardness of the concrete over a time period. There’s also a curing stage and that will gave the harden strength of the concrete with consistence of water presents.
Concrete can only be tested after 28 days, even if it keeps on harden over the years. With the hardening of the concrete, the concrete needs to be covered with plastic to keep it moist, because it dry rapidly and that is when cracks will appear. It also happened that bleeding and settlement happened in the concrete foundation or concrete slabs. Bleeding normally happened because the cement and aggregate particles have a much higher density than water.
The how to about reinforcing
Reinforcing in concrete foundation is very important. You can use mild steel or high yield steel. Steel or as they call it reinforced steel, has a strong tension on its own and combined with the remarkable strength of concrete gave it the ability to carry additional loads per square meter. The two kind of steel used in concrete is called R-bars is in mild steel, or other wise Y-Bars as in high yield steel. The mild steel bars normally have a smooth service, where the high yield steel have longitudinal or transverse ribs for a stronger bond and it is also called deformed bars. The ribs around the bar differs from manufacturer to manufacturer. The ribs are used to create a better bonding factor between the steel en the concrete.
Where the high yield deformed bars denoted with a Y prefix, the mild steel have been denoted with a R prefix. Both of the types of steel comes in an 8mm diameter to a 40mm diameter. Where the mild steel strength characteristic is approximately 230MPa, the strength characteristics of the high yield steel is at 450MPa. The 16mm and larger bars are normally used to reinforce foundations, retaining walls and beams. Where the smaller bars are use for reinforcing ground floors, first floors and up. The 8mm to 12mm bars will normally used for stirrups and column links.
The reinforced steel will be calculated by a structural engineer to determine the thickness and kind of steel that needs to be use for the foundation. Such a list or calculation schedule called a bending schedule. There they will tell you exactly what thickness, length and quantities. With the bending schedule, you will get the engineer drawing to show you how the cuts and beds must be joined.
