Footing systems are the constructions that aid in the transfer of loads from the structure and superstructure of a building to the foundation. According to the information by Hissam, Seacord & Lewis (2002), footing system requires reinforced cement concrete with a powerfully designed formwork. The footing system must, therefore, take care of the overall structure as well as to resist the various loads such as dead loads, live loads, dynamic loads, wind load, and the earthquake loads. The footing system is therefore, the core concrete framed medium rise building. This is an example of a building of a low rise concrete frame.
The design of a footing mainly aims at enhancing and ascertaining the transmission of loads to the subsoil in a safe manner which is as well economical and free from any movement that is perceived to be unacceptable during the process of construction and by far throughout the projected life of the structure or the building in general.
A number of factors are taken into consideration in the design and choice of a foundation design. Among such factors include the type of soil, the proposed period of construction the structural loadings, challenges or problems associated with construction as well as economic factors among other considerations. Of all these considerations and factors, the structural loading alongside the conditions of the soil tend to be the most considered when it comes to footing design (Krarti 2016). A footing system that is precisely, properly and accurately designed would ensure elimination or otherwise on the maximum lower differential settlements that would take place when the soil is subjected to stressing due to the imposed load of the structure or building.
Two footing systems or designed were adopted in this structure: a 150 mm thick structural raft slab that had an edge that has been stiffened alongside integral beams that pass over the piers that have been driven into a shale foundation. The raft footing serves to spread the load inclusive of the dead and live load from the structure and superstructures over a large surface area of the base in order to reduce the load per unit area (Meggers et al. 2012). The piers on the other hand were used as a bypass for the reactive soil and aided in the transmission of the superstructure load that was at the edge of the beam to a level that was lower of the subsoil in which there ease the existence of a suitable ABP.
A pier foundation is composed of numerous cylindrical columns that have large diameters and are used in the support of the superstructure as well as in the transfer of the super imposed loads to the stable and firm strata below. Pier foundation stands some feet above the ground level and is also known as post foundation. Masonry or concrete pier and drilled caissons are the main type of pier foundation footing commonly used. In the above pictures, the former foundation footing system has been adopted. Masonry or concrete piers are usable depending on the stratum level and in most cases used go as high as 5m in which masonry piers are used. The depth of the bed and the nature of the soil determine the shape and size of the pier (Dodoo et al. 2014). The arrangement of the structural members on the foundation footing system is as shown below
Pier foundation footing details
The structural connections create a balance in the building structure against such forces as compressive and tensional forces. The structural connections as well aid in the facilitation of the transfer of the load from the super structure to the stable stratum below. Column to footing connections facilitate the transfer of the load from the ground floor level through the columns into the foundation where the load is distributed over the foundation. Beam to column footing facilitates the transfer of large super imposed loads from the upper floors through the columns to the stable stratum.
Column to beam connection
Footing to column connection
Structural System of the Building (Yunus & Yang 2012)
The concrete system finds a strong foundation to rest on and is transfer the forces from the building and on the building to the ground.
The dead loads of the entire building involves the force acting downwards due to the weight of the building itself for the entire aspects of the building structure, elements, walls, among others. This downward acting force meets a strong footing system that is capable of carrying that load.
Live load of the building on the other down ward force involves to weight of the occupants and furniture including their possessions like books among others. The footing is structured to carry these loads or greater ones that varies depending on the intention of the building.
A strong footing and structural system of a building should be capable of resisting the forces of wind on everyday situation, mostly of significant force when multiplied by the building surface. In addition, the building structure should also be capable of resisting ground vigorous shakes happening horizontally or vertically considering the fact that the bigger the building, the greater forces acting on it.
The choice of the floor system is normally a thorough aspect and consideration in almost all the aspects of any building or structure inclusive of its design, construction as well as its anticipated future usefulness (Schmelas, Feldmann& Bollin 2015). At times a need arise to compromise the construction of s structure since the final choice in most cases has to meet numerous contradictory criteria.
The floor system used in the upper levels of the building is reinforced concrete floors. Concrete floor systems exist in various forms and are used in the provision of thermal comfort as well as other advantages. The floor systems can be either on-ground, suspended or a combination of both. Conventional concrete is found to be containing high amount of embodied energy (Yunus & Yang 2012). From the provided pictures of middle rise building, the upper levels have on-ground concrete floor system. Slab-on-ground concrete floors have two variants: waffle pod slabs and conventional slabs having deep excavated beams (Gambhir, 2014).
Construction sequence of on-ground concrete slab
- Planning how to place the concrete
- Preparing the ground
- Fixing the edge formwork (Spence & Kareem 2014)
- Installing service pipes
- Laying concrete underlay
- Fixing steel reinforcement in the beams
- Fixing steel reinforcement in the slabs
- Placing and compacting the concrete
- Finishing the slab surface
- Curing the concrete slab
There will be two layers of reinforcement in the floors: reinforcement in the beams and reinforcement in the slabs. The beams are used in the transfer of the dead load of concrete slab to the columns while the slabs will be used in transferring and supporting both live and dead loads. The live loads will be those of the occupants of the building while dead load will be of such equipment as furniture and the load of the concrete slab itself (Fred Hall, 2017).
The bar tags are used for identification of the various steel bars. They provide information on the properties of the steel. Among the available information on the tags, include the number of pieces of the bars in the shipment of the rebar, the various bent bar dimensions, the total weight and bar markings.
The external walls of the building are constructed from concrete blocks. This section provides a report on lying of the concrete blocks on the four facades of the building (Spence & Kareem 2014). The details of the connection as well as the accompanying wind load resistance are included. The basic aspect in walling system is to ensure having the right concrete block that facilitates installation process. Considering that the structure of the frame is very strong, the walling materials are used within them. Using heavier options such as masonry walls of bricks, stones, or concrete blocks while the lighter options being drywalls that are partitioned with light steel or wood, they form part of the string structure. For more compacts, the brick or concrete wall is plastered on the entire surface with cement plaster, thus forming a lasting and hard finish.
Shown below is an illustration of the building under construction.
Images of the walls under construction showing the external finishes of the various facades (Spence & Kareem 2014)
Connections and Fixings
Wall to foundation footing: The concrete block wall has a direct bearing support on the seating. There are two seating at one level that is used in carrying its weight. There are numerous fixing methods that are available with the most commonly used connection in a step footing foundation shown in the sketch below
Section through the wall showing insulation and flashing details (Fred Hall, 2017)
Provision of suffice mechanism of load resistance by the walls for the various loads to which it is subjected is of utmost importance. The roof may serve as a diaphragm that transmits the applied lateral load on a single set of the walls at perpendicular angles. The walls will in this serve as shear walls that aid in the resistance of the applied loads (Spence & Kareem 2014).
Principle of transverse load resistance (Spence & Kareem 2014)
The roof system of the roof frame has been elaborated in the section on the structural system of this task. The sketch shown below is indicative of where the roofing elements will be placed in the building for the purposes of clarification.'
Concrete frame buildings can be clad with any kind of cladding material. Common cladding materials are glass, aluminium panels, stone sheets, and ceramic facades. Since these structures can be designed for heavy loading, one could even clad them in solid masonry walls of brick or stone. The roof of the building has been cladded using concealed-fixed LYSAGHT KLIP-LOK 406. This is a very strong, durable and versatile roof cladding that can also be used as wall cladding. Some of the admirable properties of the cladding material include being a combination of the strength of steel, lock-action rib design and smart fluted pans in addition to concealed fastening allowing it to be used on various applications ranging from very low pitches, as low as 1 degrees roofs to those that are horizontally ribbed walling (Lee, Selkowitz & Kohler 2018). Fixed LYSAGHT KLIP-LOK 406 comes in very long lengths and hence it is possible that a single sheet can run from the ridge to the gutter without necessarily developing an end laps. Below in a pictorial illustration of the roof a typical building that has fixed LYSAGHT KLIP-LOK 406 as the cladding, noting no lapping and open fasteners.
Heat and Condensation Details
Gutter and Flashing Details
Storm Water Control
Water harvested from the surfaces is treated to be clean and thud dischargeable into any approved water course without necessarily being taken through the water treatment process. The construction of the building taken into consideration the effluents from two main areas: the ground area and the roof (Bdeir 2015).
The design of the roof has been done in such a way that it easily and effectively enables a fall. The choice of the covering of the roof determines the fall of the same roof and the fall of a roof also determine the choice of the material covering for the roof (Xu et al. 2014). Storm water is controlled using open drainage channels and gutters. The gutters are placed at the roof deck where they collect rainwater that falls on the roof of the building, which is then further channelled by downpipes into the various drainage channels that are positioned with consideration given to the slope of the site. The intensity of the rainfall, the collection area and the number of downpipes that are used as well as their efficacy determine the size of the gutter and the downpipe that have been used in the building.
Storm Water Control system through downpipes and gutters (Spence & Kareem 2014)
The hardscapes areas have been paved and have concrete box channel lay. The area to be drained and the shape of the pave area play a significant role in the determination of the size of the channel and gully that are to be used. From the channels, the effluents are directed into a silt pit before they are able to join the main street.
Channels and yard gully (Bdeir 2015)
Communication and Electricity
The main distribution center for electricity and the telecommunication mast are placed by the main entrance into the building. The distribution cables are mainly underneath and pass by the footing slab into the building. Inside the building is a surface mounted wiring system that utilizes bracket fix directly to the concrete panel Katipamula & Brambley (2005). The service cables are run below the slab for the first level of the building.
Sketches of the electricity and communication service systems
Electricity service system (Xu et al. 2014)
Methods of Prevention of the spread of fire through penetration
Passive fire protection systems are those that offer a restraint on the spread of fir and smoke offering barriers to their physical features and position to prevent the smoke and fire from spreading. Passive fire protection aids in the prevention or otherwise slowing down of the spread of fire from the room where the fire begins to the other spaces in a building hence reducing or minimizing the damage as well as offering more time to the occupants of the building for emergency occupation to seek an area of refuge (Lou & Kamar 2012).
Passive fire protection systems (Lou & Kamar 2012)
Active Fire Protection
This is an important part of fire protection which is normally characterized by the systems and items that need a specific amount of response and motion so as to work as opposed to passive fire protection. In other words, active fire protection systems are those systems which have a direct role to play in case of the occurrence of fire. Such systems as gas flooding, fire alarms, fire sprinkler and fire detection are classified as active fire protection systems owing to their ability to wither notify and warn the occupants of the existence of fire or automatically put out the fire (Bdeir 2015).
Fire detection and alarm system
A fire alarm is classified as an active fire protection which either manually or automatically sense fire or its impacts and does one or more of the following tasks: showing the zone or location of the activated detector, alerts the building occupants, summons the fire service automatically, begins controls functions that are ancillary fire related in the affected building.
Fire detection and alarm system (Bdeir 2015)
The Australian Standards relevant to the methods of prevention of the spread of fire through penetration is AS 4072.1
The building has class 3-concrete finish in which in as much as visual appeal is important, less of it is attached to architectural importance. The interior of the building is finish on 3-coats of vinyl paint while the exterior has natural stone cladding (Petersen & Bundgaard 2014).
The use of clean formwork ensures elimination of impurities such as dust and chemicals, which would interfere with the final properties of the concrete achieved. The use of unclean formwork may result into dry concrete not attaining the required compressive strength (Xu et al. 2014).
The relevant Australian Standards to concrete finishes are:
- AS 3610
- AS 36005; and
Concrete finishes are categorized into Finishes 1, 2, 3 and 4 which are dependent on the type of finish and texture of the formwork.
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