The number of storeys, as well as the bearing capacity of the underlying soil, play a pivotal role in determining the material of use. The battle of the material to be used has drawn down to concrete and steel. However, concrete is not used extensively alone because of the tensile weakness and this has resulted in reinforced concrete (McCormac & Brown, 2014). In comparison, steel is strong against tensile forces but weaker in compressive forces. Nevertheless, steel has been the most dominant material for use because of the number of advantages associated with its usage, especially for buildings which have a higher number of storeys.
To begin with, the lightness of steel proves to be very useful in places where the soils have a lower bearing capacity. Therefore, the steel frame formed is remarkably lighter than the frames that would be formed by other construction such as concrete and masonry blocks. Secondly, the ease of erection of a steel frame is commendable and as such, suitable for construction works that are time dependent.Furthermore, steel fabrication is extensively done and therefore the labor costs, as well as time, can be drastically reduced, Finally, steel is very predictable and therefore can be customized as per the site plans to meet the required standards. All these factors give steel an edge over the other construction materials. As in our case where the frame has to consider the basement, steel is recommended for use. Furthermore, the lower bearing capacity of the upper stratum may advocate for the use of steel.
The loads transmitted from the structural elements of the steel and from the different types of loading to the building are transferred to the soil stratum. However, the site conditions indicate that the upper stratum is of low bearing capacity and as such, the engineer may opt for the deep foundations. There are three types of deep foundations that may be used in this scenario: the pile foundation, pier foundation, and the caisson foundation. The groundwater conditions indicate that the foundation will have to be a conglomerate of the caisson foundation with either the pier or pile foundation. Caisson foundations are basically shells that surround the working area and provide a platform for the laying of the other foundation. Therefore, the caisson will have to be driven into the earth’s stratum to prevent the seepage of water into the working area. Any water that is in the working area may be removed by pump mechanisms. Furthermore, the level ground will have to be provided with a damp proof membrane or a blinding layer to prevent the upward movement of water into the working area. However, cofferdams may also be used and will provide reinforcement to the caisson foundation. As a matter of fact, the cofferdam may be best suited for this type of building. The pier or piles are constructed within the walls of the cofferdam and later on, the cofferdam can be disassembled and transferred to the next pier or pile.
The design engineer may opt to use the pile or the pier foundation because of the relative indifference. Pile and pier foundations are used to serve the same deep-foundation functions and the difference lies in the method of installation. Pile foundations are installed through driving while pier foundations through excavation (Valley, 2009).More to the foundation aspects fall within the basement design and construction. The building structure is to be designed such that there will be a deep basement located at 7 meters below the ground surface. Basement designs necessitate the need for deep foundations because of the uplifting forces subjected to the basement mats. However, the design of deep building pits is an additional requirement for this type of building.
Finally, the design aspects of the building may necessitate the use of braced cuts to accommodate the basement as well as the foundation level. Braced cuts are used in areas where the excavation works may involve faces that are vertical or near vertical.The excavation work may result in tremendous soil stresses which may consequently lead to the collapse. Therefore, to prevent the settlement as well as the failure of the early foundations, the bracing system may be used. There are two types of bracing systems that can be used and these basically depend on the material used whereby one system uses soldier beams while the other uses vertical steel and timber beams.
The design of the superstructure has to consider the uses of the building as well as the environmental requirements. The building has to be designed such that there is a considerable reduction in the emissions. However, the insulation properties, as well as space, determine the comfort level as well as the suitability for use. As of late, the emphasis has been towards the green building with the construction industry ranked as one of the major contributors to global warming (The leadership in Energy and environmental design, 2007).However, since the building is to be constructed with the purpose of energy as well as heat generation, the most important factors are the structural details and the insulation parameters
The frames of steel buildings may fall within the following categories; single storey lattice roof building, single storey rigid portal and medium rise braced multi-storey building (McGinley & Ang, 1993). However, since our building is made up of a single storey, the single storey lattice roof may be deemed as the most appropriate. All these frames make a considerable effort to mitigate the possibility of structural failure while at the same time the loading on the foundation system. The three types of frames are sketched below.
A typical building consists of the following elements and as such, experience and knowledge will have to be considered prior to the design. The first elements to be considered are the beams and girders which carry the lateral loads when the building is subjected to shear and bending moments. The wind loading of the building, as well as the other temporary and permanent loads, will determine the sizes (Krishna, n.d.). Secondly are the ties which carry any axial load that the building is subjected to and in turn prevent buckling. The struts and columns are members that are designed in order to meet the compression requirements of the buildings and basically transmit the loads to the foundations. The truss and the girder system of the steel building are designed to carry the lateral loads and is composed of struts and ties, The last, but not least, is the bracing system of the building. Braces are installed throughout the building structure and serve the function of resisting the wind loads that would in other instances destabilize the building.
The procedure of the design of such a building begins with the loading estimation. In this, the loading from the permanent as well as the temporary elements is determined. Temporary loads include the occupancy, partitioning, wind loads etc. while the permanent loads refer to the loads that the building is subjected to because of permanent occupancy. Permanent loads encompass the structural weight of the materials used as well as finishes. The second step is the determination of all the loadings at the critical points of the buildings. Therefore, the main elements of the building such as trusses and girders are analyzed at the critical points. It is from this analysis that the structural elements and connections of the buildings are designed. The beams, columns, floors, joists and the other elements of the building are designed using the data obtained from the previous step. Finally, the arrangements of the elements, as well as the necessary drawings, are put to paper. However, it is important to consider that the design may be based on the serviceability limit state, plastic design or the limit state method (Arya, 2009).
After the design of all the structural elements, the designers and the builders have to provide the finishing surfaces. However, heat losses and heat gains are associated with the building material used as well as the design aspects of the building (Merritt & Ricketts, 2001).In this, the heat losses are determined by the thermal transmittance of the materials used for the construction of the walling as well as the floor and roofs. The heat losses may be reduced by the use of cavities between the internal and external walls and the use of floors of lower thermal transmittance (Swinbourne, 2017). All this will be necessary for the design because of the humongous amounts of heat generated.
Arya, C., 2009. Design of structural elements. s.l.:Taylor & Francis.
Krishna, P., n.d. wind loads on buildings and structures, s.l.: s.n.
McCormack, J. C. & Brown, R. H., 2014. Design of reinforced concrete. s.l.: John Wiley and sons.
McGinley, T. J. & Ang, T. C., 1993. Structural steelwork: design to limit state theory. s.l.: Biddles Ltd, Guildford, and King’s Lynn.
Merritt, F. S. & Ricketts, J. T., 2001. Building design and construction handbook. s.l.:s.n.
Swinburne, R., 2017. Green infrastructure: a brilliant cities report. s.l.:s.n.
The leadership in Energy and environmental design, 2007. Green building rating system. s.l.:s.n.
Valley, M., 2009. Foundation analysis and design. s.l.:s.n.