RELIABILITY ANALYSIS OF AXIALLY COMPRESSED COLUMNS REINFORCED BY SECTION ENLARGEMENT

The purpose of this paper is to determine reliability index of axially compressed columns based on the current specifications and to analyze some influence factors. Stationary binomial random load model is applied to obtain load statistical values and stationary random process is used to establish simple and practical resistance model. Based on theoretical derivation and the new version specifications, a computer program is developed to obtain the reliability index of reinforced columns. And the influence of concrete strength variation coefficient delta(c0). the bearing capacity insufficiency factor K as well as the ratio of construction load to design load K-N on reliability is studied. The results show their importance order is delta(c0), K and K-N. Therefore, inspection and assessment of existing structures is indispensable for reinforcement design. Furthermore some solutions are proposed to ensure sufficient reliability and enough safety: restricting the increase extent of the load compared to bearing capacity. applying load-off construction and so on. The outcome is beneficial for reinforcement design and helpful in engineering practice.