Investigation on the Effects of Formwork & Scaffolding Types in Building Projects in Addis Ababa

Abstract

In building construction there are temporary structures such as formwork and scaffoldings have often been just as elements used to construct the permanent structures. However, much greater attention has been paid to the design of permanent structures than to the design of temporary structures. Poor qualities of formwork materials affect the quality of the concrete surface finish, size and dimension of permanent structural members. The objective of this research to investigate the effects of formwork and scaffolding types in building projects in Addis Ababa. The study design of this research was descriptive and exploratory design. The objective of the research was achieved in accordance with the methodology of Study; Literature review, Survey (i.e. site observation) and Questionnaires. The researches was conducted by using purposive sampling method and select ten building projects from Addis Ababa that are under construction during the study period. The projects contain different category of building such as offices, condominiums, and hospitals. The qualitative and quantitative data that gathered from data collection process was analyzed by using statistically and descriptive analysis method. Questionnaires and interviews were distributed in the projects to get relevant data which helps to achieve the objectives of this thesis. Thirty copies of questionnaires distributed to the targeted respondents however, 27(90%) useable questionnaires collected from the respondents. The result showed that 70% of the respondents use combination of both steel panels and timber boards as formwork materials, 5% of the respondents use steel, 20% use timber and 5% use yellow timber as formwork material. In addition to this, in Addis Ababa 10% of building contractors use combination of both steel and timber scaffolding and 30% use only steel and 60% use timber scaffolding. The results showed that, Steel and Timber are the most commonly used formwork and scaffolding materials in Addis Ababa. Even though, Steel formwork reuses many times with high rate affect the concrete surface finish. In addition to this, it is easy for erecting and striping with good speed of construction. On other hand, timber formworks was more preferable for the smoothness of surface finish but slow down the speed of construction and cannot reuse many times like steel. Timber scaffoldings were an ideal solution for irregular shaped building structures but its quality will be affected easily by bad weather condition. It cause failure on the structural elements, injured the workers and difficult to use in high rise buildings. On other hand, steel scaffoldings used for large projects or in high rise buildings. Moreover, Steel scaffolding has longer life than timber scaffolding and much safer for the workers and structures. In terms of quality and safety steel scaffolding was more preferable. Steel formworks and scaffolding should be maintained after every reuse, cleaning it well, painting and stock in suitable place in order to reuses many times and to keep its quality was recommended.