Evaluation of capacity reduction factors for the design of reinforced concrete structural elements case study: Indonesia

Although there has been many changes in the development of the safety provisions for the Indonesian codes of practice since 1971, most of the changes have either been compromised or combined with the corresponding codes of the developed countries. For example, the current Indonesian concrete code (SKSNI) has adopted many factors from the American Concrete Institute (ACI 318) code, the British Standard (BSI,1985) code, the Architectural Institute of Japan (AIJ,1994) code and the Dutch code (GBV, 1985). 

Comments amongst the practicing engineers as the end user on the existing code often refer to the inconsistencies of the code provisions and the field practices in Indonesia. As Indonesia is a country with an unbalanced distribution of skills and knowledge between the main island Java and other islands, providing an unified national standard without referring to the regional practices adversely affects the safety levels. This thesis attempts to demonstrate the inconsistencies in the provisions of the current Indonesian concrete code (SKSNI T-15, 1991) and the field practices in the main island Java. An extensive probability analysis has been carried out based on the statistical field data collected from several projects and material testing institutions for the demonstration of the aims of the thesis. From the probabilistic analyses of the statistical data, load and resistance factors for some important structural actions (viz, flexure, compression, flexural shear and punching shear) have been evaluated and compared with the provisions of the SKSNI, ACI 318 and AS 3600-1988. Gravity load (dead and live loads) and lateral load (dead, live and earthquake loads) combinations have been considered in the evaluation of the load and resistance factors for the selected structural actions. The thesis proposes the evaluated load and resistance factors as rational provisions reflecting the field practices of the Java island and recommendations that similar studies be carried out to reflect the regional practices in the safety provisions of the Indonesian concrete code.