Do you know that the Burj Khalifa with 163 floors is the tallest high-rise structure in the world?” Also known as high-rise, and in contrast to a low-rise building, a high-rise building is a very tall building higher than 21 meters (21 to 29 floor) that can either be used for offices, apartments or a combination of both. The rise of the high rise was made possible due to the advent of elevators and quality building materials such as rebars and cement. Actually, the combination of these two (cement and rod) in construction is called “reinforced cement concrete” (RCC) or reinforced concrete (RC)
It consists of a flat horizontal surface called beams, vertical members known as columns and flat planes known as slabs which is the floor we step upon. Reinforced concrete ground floor slab resting directly on the subsoil or foundation is known as ground-bearing slab while the other slabs found in the building are called suspended slabs. The advantages reinforced concrete ground floor slabs provide to any building include; resistance against internal tensile forces, thermal comfort, durability, design, etc. Reinforced concrete slabs in no small way also adds to the strength of a building and therefore indispensable to the building of a high-rise. It can either be built on site or prefabricated. The major steps towards building a reinforced concrete ground floor slab are:
Steps To building A Reinforced Concrete Ground Floor Slab of a High-Rise Building.
1. Getting the Building Permit:
Well, a structure such as high rise is not possible without a building permit. This is to ensure that safety is guaranteed, contracts are handled as should be by the contractor and that the intended building conforms to standard or building code. To obtain one, the building plan and permit application, and a permit fee are required for review.
Actual construction starts with the testing of the site by a soil scientist to determine how deep the foundation should go in. After this, excavation which involves moving earth, rocks or other material out of the site is done. It is carried out in order to create a building foundation. Excavation is also done to remove unwanted elements from the site. You should make sure that the method statement for the excavation is approved before work commences.
3. Completing the concrete columns below ground level:
After excavating the ground and making foundations, reinforced concrete columns, retaining walls, and shearwalls are erected which will act as a carrying channel for the structures above. The MEP works should be also considered during the construction of the columns underneath the ground floor. It may even better if you read the procedure on how to cast a concrete column.
4. Installation of Forms of Slab:
Slab forms consist of horizontal load-bearing structure which supports the form-lining and transfers the forces into the shoring. Slab form can be in the form of a wooden structure or a pre-constructed metal that are joined or connected together to highlight places and depth a slab should be. The form also explains the type of joint that is to be used (either construction or contraction).
The formwork engineers have the duty to inspect and make sure that all formworks are credible and good before pouring in the concrete.
5. Steel Reinforcement Installation on the slab and beams:
After the forms have been installed, laying of the reinforced slabs commences. Installation of steel beams, drop beams and extra bars are also done in this stage in a bid to provide support and strength to the building.
6. MEP Service Installations:
Mechanical, electrical and plumbing (MEP) works start from the ground slab. MEP consists of three technical work departments that must work together for the success of a project. It includes installation of electrical appliances, piping, etc. all geared towards making the building interior and exterior suitable for habitation.
7. Inspection with the Engineer/Consultant:
After the laying of steel reinforcement and MEP rough-ins, there would be an inspection by the engineer or a consultant to examine and confirm if the layouts are good and can carry the load that will be given it. The inspection will also extend to slab forms to ensure that they can hold the concrete when poured.
8. Inspection with the Municipality Engineer:
The municipality apart from issuing permit also inspects the project to see if it conforms to the standard and to ascertain if the project is going as specified in the filed building permit. As a civil engineer, the municipal engineer also checks for technical issues, operation and political interference in the project
9. Pouring Concrete:
If everything is deemed fit after a series of inspections, the concrete is poured on top of the rods in the slab forms that have already been laid out. Usually, machines like cement mixers and dispensers are used to mix and pour the concrete to form a slab. You should make sure that concrete vibrators are available during concrete pouring.
10. Curing the slab:
Curing a concrete help delay drying shrinkage until the concrete is strong enough to resist shrinkage cracking. It also helps the slab retain moisture so as to make the concrete gain more strength. This is the key to achieving the design strength, durability, water tightness and wear resistance. In fact, all the desirable properties of concrete are improved by proper curing.
The minimum size of a reinforced concrete slab is restricted to 4 times the nominal size of aggregate. Furthermore, the thickness of a slab is affected by the location of the project, the type, and span of the slab. The reinforced concrete ground floor slab is indispensable to erecting any building not only because of the strength it adds to the building but also because of durability and design. An improper slab will lead to wreckage and havoc on the safety of humans. Slabs help in the resistance of loads like dead loads, live loads, dynamic loads, wind and earthquake load by transferring the forces to the ground/soil.