Functional Requirements Of Ground Floors

Published Date: 02 Nov 2017

A: The functional requirements of ground floors

My research into compiling this assignment has led to the opinion that creating a floor, whatever materials, mean and location require careful consideration and experienced professional analysis of what is required of the floor, what it is intended to be used for and what materials will be incorporated into the makeup of the floors and layers within. Although factors such as cost and timescale are important factors and may well influence the choice of floor type and its makeup, there are more fundamental performance requirements which should be given priority first.

It is vital to note the role that soil conditions and its makeup together with the earthwork support systems and foundations underneath any floor play, as fundamentally, the ground underneath any floor and structure no matter what size, is the final end point for load bearing stresses transferred down into the soil from ground level. Any movement within the ground, either upward or downward will affect the floor and its performance. Sub grade can either be natural soil landfill; the sub grade supports the underlying floor and the floor with its imposed loads.

What is the floor to be used for?

For instance, will the floor be required for a domestic dwelling, commercial offices or for industrial businesses that will require the floor to carry the loads of heavy plant machinery and transport, again the floor may also be within a chemical processing plant which has large quantities of acids sulphates and other chemicals within the floors proximity which could cause serious damage to the floor, or a sports hall, that will have frequent fast flowing traffic imposed upon it.

This will have obvious differences in the characteristics of the floors individual design and floor finishes. Some floors need a higher level of resistance as they may be used

by factories such as a metal working plant, where abrasive materials are often used, and would therefore require specialist hardeners, toppings or coats to add extra resistance

and durability.

Industries such as a vegetable canning factory or meat packing plant use acids that can attack concrete. Without specialist protection concrete floors in this environment

would have a short lifespan .Although not a lot can be done to make the concrete less prone to chemical attack, designers usually introduce specialist floor coatings or toppings

to add resistance to such attacks. If a floor is to be used by wheeled vehicles it is often recommended that any joints or cracks are filled with semi rigid epoxy to prevent

spalling.

Similarly if the building is to be used as either a food processing or pharmaceutical plant then it would be essential to apply additional sealing for sanitary reasons.

If it is is to be an electronic plant then non sealed points will cumulate dust which could have detrimental effects to the products produced and plant.

A good example of floor topping is shown on the photos below….These were taken by myself within Swansea Metropolitan universities science testing laboratory,

February 15th 2013 and show the type of machinery load imposed upon the floor and also the breakup of the floors topping due to wear, exposure to corrosive materials,

and impact of tools dropping onto the floor.

Strength and Stability

A floor has to have the strength to carry the load imposed upon it, whether it be live loads such as people, or dead loads such as machinery furniture or fixtures and fittings,

and the stability to resist excessive movement.

A floor systems connections and condition affect the buildings structural integrity. It must safely support moving loads, so therefore the floor system must be relatively stiff

whilst maintaining its elasticity. Deflection, rather than he bending stress rating is the controlling factor.

Most floor systems of a building are not exposed to climatic or weather elements, but must still be durable enough to support traffic, resistance wear and be easily maintained.

The Floor system is a structures horizontal plane which must transfer the weight stresses from above to the ground below.

Above ground level a floor design needs to be able to transfer loads laterally to beam supports, whilst providing lateral support for adjacent walls.

Durability

A floor should to be designed and constructed of materials hard enough that can resist cracking & breakages and have the ability to perform its required functions over a desired life span, with as little maintenance as possible.

As well as being strong, there is also a need for the floor to be waterproof and should contain a damp proof / waterproof membrane to resist ground moisture. Condensation either surface or interstitial) will encourage fungi and pest infestation, not only having a detrimental effect on materials and equipment stored but, the health and wellbeing

of the people working in such an environment.

With reference to ‘Approved Document C (2004) of the Building Regulations, Clause 4. (15.2.13)’

Climate Barrier - The ground floor is required to keep the moisture out and the warmth in, enabling it to maintainA comfortable environment for its inhabitants to live in

and carry out the social activities that the building was designed for’

INSULATION

It has been established that between 15 - 20% of total building heat loss is through the floor, so by insulating, will reduce the risk of condensation forming and improve

internal conditions and sound insulation whilst restricting thermal bridging at floor/wall junctions, therefore reducing heat loss.

Fire resistance

It is another performance requirement that a ground floor should offer a good degree of resistance to collapse, flame penetration and heat transfer.

Question b: EXAMINE FACTORS AFFECT THE CHOICE O GROUND FLOOR TO THE BUILDING!

The plan drawing of section AA, illustrates that the building is to be constructed with a portal frame and will be 45 metres long, with steel stanchions positioned 5 metres apart. The stanchions are supported upon individual pad foundations. The attached plans suggest that in view of the dimensions required the building is to be used for an industrial purpose, such as a manufacturing or processing factory or warehouse.

Such buildings, like engineering workshops or food processing plants will often have very heavy loads such as plant machinery or wheeled vehicles such as forklifts to be able

to transport materials and stock.

For this reason the following factors have to be taken into consideration when designing and producing the required floor:

Loads

Surface texture

Wear resistance

Joint and crack sealing

Resistance to chemical attack.

As floors have to carry loads imposed upon it, it is important to pre plan in the design process for behaviour that may occur in the floor once constructed.

i.e., there will be both hot and cold temperature variations, vibrations, thrust movement, impact and weight pressures all imposed by both live and

dead loads.

The location plan shows neighbouring businesses and roads and railway, so one would assume that he location of the proposed building is to be located in a form of industrial estate , and built on established ground. The quality of the sub grade is a major factor in the structural design of any ground supported floor.

Essentially, for a building with the stated dimensions, there are three types of floors to choose from, and all will have their own slight construction variations depending

on architect design, client choice and contractor resources thus being: a solid concrete floor, suspended concrete (precast / reinforced precast /in-situ) or timber

suspended floor.

Due to the size of the site, and more crucially, its intended business use, I am ruling out suspended timber floors, as it is to be used for industrial purposes

so the weight imposed and wear and tear on the floor surface would be impractical and require regular repair maintenance.

Suspended concrete floors are becoming a common means of ground floor construction as they are not so labour intensive so reduce on site time and cost. Additionally,

they can be adjusted during their design process to improve strength to weight ratios. They tend to be used on sloping areas or when soil conditions below ground have

a low bearing tolerance or contain a high volume of chemicals or water levels. Such floors are constructed in pre-stressed concrete beams, spaced at intervals and

completed with concrete block joints to create a robust and hard wearing floor system that could be used within an industrial environment.

As per the attached diagrams, consideration needs to made with regard to the thermal performance of the floor, particularly whether to locate insulation above

or below the concrete slab, and the required heat response time for the people using the building...i.e. a factory setting the heating will be required over a more prolonged

period, so it would be more beneficial to place the slab above insulation rather than beneath it, where this positioning would be more appropriate to domestic dwellings

when a faster heating output is required.

It is important that soil conditions are evaluated as the soil will always deflect under stress and load. The earthwork support required needs to be correctly implemented to limit ground movement. Dewatering and moisture penetration measures need to be introduced, such as a damp proof membrane as does the restriction of chemical or sulphate

attack from within the ground also needs to be assessed.

As the attached plan shows, the ground level is not sloping, but will contain the additional weight of a mezzanine floor, which is also to be constructed of reinforced concrete, with a continuous supporting wall. Therefore, taking into account the weight of this additional floor, I am of the opinion, a ground bearing floor would be the most suitable choice for the building.