Optional Technologies Adopted in the Construction of Building Elements - Essay Example

 Optional Technologies Adopted in the Construction of Building Elements Introduction The construction of commercial buildings is a field that has evolved over time and numerous technologies have been brought forward with regard to the construction of its various elements. This field has involved projects of both small and huge magnitudes from the construction of small commercial buildings to large and complex commercial buildings. For effective execution of a construction project, proper planning is required plus an involvement of all relevant stakeholders. Usually this process ranges from the planning stage to the design and execution stages until the building is ready for occupancy (BRYAN, 2010, p. 12). Design professionals significant role in the quality of the built environment cannot be denied. Buildings in the contemporary world are a complex undertaking that require many different skills and materials. In this regard, the capabilities of the engineers and architects on the integrated design team are critical for the overall success of the design. In order to carry out the design and propose various alternatives, some background data is often required. This is usually with reference to the location of the proposed project and its various jurisdictions. The design process is then guided onwards by the knowledge of such project information. It is based on this that the relevant safety factors can be applied in the design so that the proposed methods and constructional technologies are safe and appropriate (EMMITT, BARRY & GORSE, 2010, p. 14). With the layout plan given for a proposed four-storey commercial building, with its components and the boundary conditions, different optional building technologies can be used to come up with the most appropriate designs. The building elements considered are as follows: i. Basement ii. Superstructure including the frames and the floor systems. iii. Cladding and roofing i) The basement Basements in commercial buildings are in most cases constructed to serve as foundations for the superstructure of the building, and in others to increase its utility to provide space that can be used by occupants of the building (FLEMING, 2005, p. 33). When adequately and properly constructed, they can be used for the following purposes: To resist the imposed loads of the soil from the ground surrounding the building; To control the temperature and moisture fluctuation in the building; and To help maintain sufficient air quality control inside the building and provide adequate living conditions. The intended use of the basement must be determined first before any design decisions are made. This will also have an impact on the quality of the basement. The level of performance of the basement areas is to be determined from the onset of construction to help in cost estimations and the material choice for the basement and its surrounding features. Good and proper designs often require a better understanding of the key critical and technical issues and the conditions under which the construction should take place, including both underground and environmental issues. Before the implementation of any key constructional procedures of the basement, the factors that should be considered would include: Construction factors: These factors majorly consider both the availability and cost of materials and labour, which are usually extremely important in the construction of all the structural elements of the building. The availability of materials is significant because it influences the costs of materials to be used in the building construction. Most contractors who are engaged in the construction would, most of the times, prefer the readily available materials and those that are found close to the construction site as this would enable them to minimise costs. The ready availability of materials also has a huge influence on the completion time of the construction as it would encourage shorter haul distances (DEPLAZES, 2005, p. 40). Performance factors: The basement should be built in a way that it amasses the strength to withstand the stresses from the soil, including hydrostatic pressures, which is a critical factor in this scenario because of the level of the water table, and to control the flow of moisture, air and gas to minimise noise transmission and fire hazard levels. Continuity in construction and how it is joined with the other elements: Before the construction of the superstructure, the basement has to be in continuity in construction, both with the portions above and below the ground. The basement has also to be constructed so that it allows for the construction of floor slabs, joints and intersections (DEPLAZES, 2005, p. 46). This continuity is important in construction so that no single structural element acts in isolation. This could result in either partial or complete failure of the building structure. Consideration of the roles played by different construction materials: Some of these materials include drainage, damp proofing, waterproofing, insulation and finishing materials both for the interior and exterior layout of the basement. Of particular importance, too, would be the materials for air and soil gas barriers. These materials should be given due attention both in the design and implementation stages. Other consideration to be given while constructing the basement with the chosen construction technology would be: Whether the chosen materials fit their intended purposes, both structurally and aesthetically; Whether the chosen materials are compatible with each other; Whether the chosen technologies and materials are legally accepted by authorities and are safe for use; and Whether the chosen technologies and materials provide necessary environmental controls and checks. In constructing the basement, enough consideration should be given to the underground water level. A sufficient amount of excavation should be done to get rid of the demolition waste to improve the bearing capacity of this ground. Excavation should be done depending on the amount of sand to be removed and the expected size of the basement. The ground should also be checked in order to ensure that it forms an adequate and safe surface for the structure. One of the optional technologies that would be applied to build the basement would be the use of cast-in-place concrete. After doing the necessary excavation and the ground found to be hard enough to hold the structure, blinding concrete would be placed first. The foundation of the structure would then be built on this surface, followed by a foundation wall, cast in situ and protected both on its inside and outside. This protection can be done either by the use of extruded polystyrene boardstock or insulated concrete forms (ICF). Water proofing materials should also be applied to help in preventing underground water from penetrating into the building. The use of cast-in-place concrete usually considers factors such as the type of mix often specified and the quality of workmanship used (BRYAN, 2010, p. 26). However, for a 4-storey commercial building, a buoyancy raft is vital for a stable basement. The buoyancy raft is obtained through displacing the weight of earth or overburden by the volume of a large voided foundation. The figure below shows a buoyancy foundation for a 4-storey commercial building. Figure 1a: buoyancy raft (Source: abuildersengineer.com. Image by Unknown) The bottom slab forms the basement of the building as shown: Figure 1b: Cellular buoyancy foundation (Source: abuildersengineer.com. Image by Unknown) This kind of construction has an advantage over other technologies in certain circumstances, especially in urban settings, due to the factors such as: Its ease in construction and ready availability; Faster placement speed; and Because of its lower cost of transportation. While using this technology for basement, prefabricated panels would be arranged uniformly to cover the entire surface of the basement. This arrangement would take place both with the guidance of the architect and the engineer in charge. However, a particular concern with this construction technology will be the effects of the underground water which could find its way into the building through the foundation. To curb this problem, proper and adequate site grading and basement drainage should be provided (DEPLAZES, 2005, p. 36). ii) Superstructure involving frames and floors The superstructure of a 4storey commercial building will be composed of a system of beams, columns and composite floor elements interconnected with one another in a fashion to transfer all the loads to the building foundation. In building the structural frame and the floor system of the commercial building, one optional technology that would be applied would be the use of light steel framing. This presents a simpler technology of construction which employs faster and cheaper methods of construction. It involves mostly the use of steel as a construction material. In this kind of building technology, use is made of light steel, usually of C sections that are cold roll-formed from galvanised steel strip of smaller thicknesses. The most important part of the section is the floor grids. Floor grids define the spacing of the columns in orthogonal directions. This is influenced by: The planning grid. This is normally based on 300 mm units but basically on multiples of 0.6, 1.2, or 1.5 m. The use of internal space. The column spacing along the facades. This depends on the façades material which is typically 5.4 to 7.5 m. The role that the building is expected to serve. As shown in figure 2 below, along the façade line, the importance of the column system comes into play especially in regards to supporting the cladding system. For instance, a maximum column spacing of 6 m is important for brickwork. This will result into a stable internal column system. The figure below represents a design for typical column grid for four storey building Figure 2: column grid (Source: steelconstruction.info. Image by Unknown) Concrete cores are the preferred system for storey buildings up to 30 floors high. However, the steel framework precedence the concrete core for stability of the building. For a 4 storey commercial building, the beams often span directly between the columns on the perimeter and the concrete core as shown in figure 3. In this regard, there is need for special structural design for: The design of the heavier primary beams at the corner of the core The beam connections to the concrete core Fire safety The figure below represents a design for beams around a concrete core. Figure 3a: A design for beams around a concrete core (Source: steelconstruction.info. Image by Unknown) Figure 3b: A braced steel core (Source: steelconstruction.info. Image by Unknown) Considering the multiple use of the building to be constructed and the flexibility requirement of the floor plan layout, the design should take into consideration a range of factors that include: A structure that would allow the transfer of loads either through the columns or walls on the upper floor levels to be different from those floor levels below; A structural frame which is compatible with the different uses on the constructed floor levels; A structure providing access to the upper floor levels, which does not depend on the lower floor levels; Provision of an effective fire resistance mechanism and compartmentation, which gives a different fire safety measure at the different floor levels; Provision of an increased level of acoustic insulation between the various spaces of occupancies; and Provision of a different but visually compatible architectural treatment of the offices and spaces specified for the other uses. The steel frame walls should be made as storey high panels and used to support floors by making use of Z sections over the wall. The floor sections however have to be of smaller thicknesses. A rebar for such section is normally a requirement for fire resistance purposes. The structural frames should consist of a series of beams and columns arranged regularly on a grid where the floors span over the beams. The floor system is usually at the choice of a designer and is normally based on such factors as: The speed of construction required; Simplicity and familiarity; Service integration; Need for adaptable space; Aesthetics and acoustics; and Cost. Based on these factors, use of a composite floor system for the building could be adopted. This form of construction consists of shallow floors reinforced usually with an upper layer of mesh. It consists of beams and connectors welded to the floor system acting as a composite. The floors can achieve a span of up to 5 m and can provide perfect designs for multi-storey office buildings (INTERNATIONAL CONFERENCE ON ADVANCES IN BUILDING TECHNOLOGY, ANSON & LAM, 2002, p.74). This form of construction comes with different advantages over other forms, some of which include: Supports increased construction speeds; Reduced number of crane lifts required for the decking; Reduced transportation time and cost as the as the decked pieces can be stuck into bundles; and Once in place, they can be used as an appropriate working platform and can also be employed for the storage of construction materials. These technologies utilise a mass of steel as construction material. Over the other materials often used for such constructional purposes as the precast concrete, steel has got numerous advantages that include: Grater constructional speeds: Since it uses mostly pre-fabricated components, the construction time is usually less. Lighter in weight: Compared to concrete, steel is lighter in weight for equivalent strength requirements. This usually helps in cost saving of materials. Safety and quality: Since the elements are normally pre-fabricated in factories in controlled conditions, their qualities are enhanced, and this presents a safer working environment especially when they are just to be installed on site. Environmental advantages: Speed is recyclable and thus can be re-used without degradation. iii) Cladding and Roofing Cladding is where one material is applied over another, usually to prevent the covered material from the adverse effects of the external environment. Cladding could also be carried out for aesthetic purposes. In most buildings it serves as a control element, used normally to direct water preventing it from entry into the building structure (BASSLER, WANG & SAKAMOTO, 1992, p. 66). The optional technologies that could be used to construct the cladding systems of such a building would include: A brickwork that has been supported on steel beams at each of the floors; A render bonded to a sheathing board and fixed on the light steel walls of the building; and A rain screen system fixed on the horizontal rails of the building. One optional technology that could be used for roofing is the application of commercially produced tiles supported by battens spanning between roof trusses, which could be placed at 600-1200 centers. However, for the commercial storey building and to create habitable space, built-up double skin cladding can be adopted as shown in figure 4 below. This could be developed through either the use of a light steel open roof system or placement of purlins spanning between cross walls (TAUNTON PRESS, 2005, p.17). Figure 4: The built-up double skin cladding (Source: steelconstruction.info. Image by Unknown) It consists of a metal liner, a spacer system, layer of insulation, and an outer metal sheet. However, it is worth noting that this type of cladding system must be supported by secondary steelwork because sometimes they might be limited by the spanning capability of the cladding sheets. Conclusion The construction of buildings is a field that has evolved over time and numerous technologies have been brought forward with regard to the construction of its various elements. The emerging technological trends have helped shape the building industry for the better. With proper technology, the complexity of a building has now been reduced to admiration for most people. However, it is worth noting that proper planning is significant for effective execution of a construction project. In normal circumstances, this process ranges from the planning stage to the design and execution stages until the building is ready for use. References BASSLER, B. L., WANG, M. L., & SAKAMOTO, I. (1992). Cladding. New York, McGraw-Hill. BRAMBLE, B. B., & CALLAHAN, M. T. (2011). Construction delay claims. [Frederick, MD], Aspen Publishers. BRYAN, T. (2010). Construction technology: analysis and choice. Chichester, West Sussex, U.K., Blackwell. DEPLAZES, A. (2005). Constructing architecture: materials, processes, structures : a handbook. Basel, Birkhäuser-Publishers for Architecture. EMMITT, S., BARRY, R., & GORSE, C. A. (2010). Barry's advanced construction of buildings. Chichester, U.K., Wiley-Blackwell. FLEMING, E. (2005). Construction technology an illustrated introduction. Oxford, UK, Blackwell Pub. http://search.ebscohost.com/login.aspx?direct=true&scope=site&db=nlebk&db=nlabk&AN=137733. [Accessed: 16th December 2014] INTERNATIONAL CONFERENCE ON ADVANCES IN BUILDING TECHNOLOGY, ANSON, M., KO, J. M., & LAM, E. S. S. (2002). Advances in building technology proceedings of the International Conference on Advances in Building Technology, 4-6 December, 2002, Hong Kong, China. Amsterdam, Elsevier. http://www.engineeringvillage.com/controller/servlet/OpenURL?genre=book&isbn=9780080441009. [Accessed: 16th December 2014]. STURGES, W. G. (1991). Towards a definition of sustainable construction technologies, a framework of performance criteria evaluating three wooden light frame floor and roof structural systems in the Cascadian bioregion. Thesis (M. Arch.)--University of Oregon, 1991. TAUNTON PRESS. (2005). Roofing, flashing & waterproofing. Newtown, CT, Taunton Press. abuildersengineer.com, n.d. photograph, viewed 16th December, 2014, . Steelconstruction.info, n.d. photograph, viewed 16th December 2014, . Steelconstruction.info, n.d. photograph, viewed 16th December 2014, . Read More