There are also some other techniques used for strengthening a reinforced concrete slab such as:
- Increasing the shear bearing capacity of the slab by adding steel plates strengthened by vertical screw bolts.
- Strengthening of the slab by post stressed reinforcement.
- Adding steel beams.
Some very effective methods of strengthening the basic design structure of the house are given below.
- Put First Things First. To start with, you should address the worst possible problem.
- Make Foundations Waterproof.
- Install Floor Connectors and Tie Rafters.
- Maintain or Dig Drains.
- Replace Loose Roof Shingles.
Non Destructive and In-situ Tests for RCC structures
- Cut And Pull Out Test (CAPO Test) Cut and Pull Out (CAPO) is a reliable test method to determine the in-situ compressive strength of RCC structures.
- Rebound Hammer Test.
- Core Tests.
- LOK Test.
- Maturity Method.
- Ultrasonic Pulse Velocity Test (UPV)
- Impulse Response Test.
- Impact Echo.
Continuous or Spot Footing Foundations. Both spot and continuous footings are regularly used in the commercial foundation industry. These footings are designed to spread out and distribute the load to a wider area as it enters the ground. Having a wider area at the bottom greatly increases the carrying capacity.
Reinforcing the framing of an
old house can be done in a multitude of ways.
This guide offers ideas on how to correct these common issues:
- Add Support to Existing Main Beams. Main beams can be reinforced with steel columns, wood columns, and even masonry piers.
- Support Beams and Joists.
- Transfer the Load.
Following are different types of foundations used in construction:
- Shallow foundation. Individual footing or isolated footing. Combined footing. Strip foundation. Raft or mat foundation.
- Deep Foundation. Pile foundation. Drilled Shafts or caissons.
While not a requirement, a concrete slab foundation provides a solid, clean surface for your steel building and can help it last longer. Since the building will require anchoring to minimize shifting, pouring a concrete slab gives you a chance to pour footings as well.
How to Calculate Footing Size
- Determine the width and length of the cement slab in inches.
- Divide the width by 12 to convert it to feet.
- Divide the length by 12 to convert it to feet.
- Determine the depth or thickness that is required for the footing in inches.
- Multiply the width by the length and then by the depth.
A concrete mix of 1 part cement : 2 parts sand : 4 parts coarse aggregate (by volume) should be used for footings. Concrete must be placed within half an hour of mixing. Brickwork – Place your concrete into your trench.
You can look up the recommended footing size, based on the size and type of house and the bearing capacity of the soil (see the table above). As you can see, heavy houses on weak soil need footings 2 feet wide or more. But the lightest buildings on the strongest soil require footings as narrow as 7 or 8 inches.
The footing is a type of shallow foundation. Foundation can be shallow and deep. Footing includes slab, rebar which are fabricated of brickwork, masonry or concrete. Foundation types include piles, caissons, footings, piers, the lateral supports, and anchors.
There are several kinds of shallow footings: individual footings, strip footings and raft foundations. Individual footings are one of the most simple and common types of foundations. These are used when the load of the building is carried by columns. Usually, each column will have its own footing.
Dig your new footings, min 1m deep, and to satisfy building control. When you expose existing foundations, normal practise is to drill holes into it then insert rebar, ipoxy resined in, leave bars protruding so as they tie into new concrete foundations.
Provide total depth of footing as 670 mm, so that the effective depth = 670 – 50 – 16 – 8 = 596 mm. (The total depth is, however, increased to 750 mm in Step 7.)
Prepare the dirt before pouring concrete. If you are constructing a patio, shed or a sidewalk, the process often starts with pouring a solid concrete base to provide sturdy support. Home owners can accomplish the task themselves by pouring the concrete directly on the ground in the installation area.
Unfortunately, asking different people, who aren't in the trades, you can get you different answers. “When it comes to using wire mesh vs. rebar, the short answer is: use both!” or Mesh is for keeping chickens in the barn. Rebar is for concrete reinforcement.” or “Wire mesh is a costly choice.”
It's false economy to do concrete without putting in rebar and mesh. Rebar around the perimeter at the least, and mesh over the rest. Pull it up when pouring so it is not resting on the bottom of the slab. You don't need the fancy rebar supports, a stone or broken brick will work just as well.
Rebar is easy to set into place before pouring the concrete. It helps to reduce the cracking and breaking that is common in concrete because of its brittle properties. Rebar provides strength to concrete and saves money for the purchaser since the concrete slab, blocks or building will last longer.
Concrete Slab Rebar Reinforcement
The same variables influence the type of concrete to be poured for the slab and how thick to pour it. However, many engineers suggest a minimum distance of one slab thickness between rebars and a maximum of three slab thicknesses.No, they do not. Larger projects or slabs may need steel reinforcement to provide support or extra strength. Wired mesh can also help resist cracking. However, not every piece of concrete necessarily requires that extra boost.
2. Thickness at the edge of footing: In reinforced and plain concrete footings, the thickness at edge shall be not less than 150 mm for footings on soils nor less than 300mm above the tops of files for footing on piles.
Step -1: Determining size of footing:
Loads on footing consists of load from column, self weight of footing and weight of soil above footing. For simplicity, self weight of footing and weight of soil on footing is considered as 10 to 15% of the vertical load. Therefore, total load P = 1100 kN.Reinforced Cement Concrete column is a part and parcel of RCC frame structured building. Reinforced concrete foundations are designed on the basis of column loads and moments at base and the soil data. It belongs to a vertical member that delivers loads from slab and beam directly to succeeding soil.
Take the total width of the footing and find out the spacing between bars. Divide width of the footing(after subtracting coverage which is generally 40–50 mm) by spacing distance between 2 bars, Result will be the total number of bars.
