Since I am not really brilliant in deriving comprehensive structural reliability assessment (SRA), most of the time I will  use simplified structural reliability assessment (SSRA) to calculate reliability index or beta index. Yes, I got a whole lot of questions when presenting the results. Question like " Isn't it too conservative applying SSRA for assessing high risk structure?" or "Is it accurate?" or "Why don't you use SRA instead of SSRA?". Well, frankly SRA is undoubtedly much more accurate and the right way to assess reliability status of existing structures. However, it will takes more times compared to SSRA, and more time mean more working hour costs to be reimbursed, which one condition management didn't like. Another thing is, it is really hard to find a good engineering consultant that have ability and capability to run full SRA due to its complicated calculations and theory. If money and time is not the problem, than I can prescribe one place to do it (it's pretty far and will cost you at least RM 1/2 Million). 

SSRA being developed about ten years ago and only tailored to South China Sea region. So, any structures outside this region more works need to be done!! Sorry..
SSRA methodology is based and calibrated from more complicated SRA. A group of offshore structures with various configurations such as 3, 4, 6 and 8 legged platforms are modeled and undergone SRA. Each structure will have their own unique loading and resistance spread denoted by variance and rate of change of each parameters denoted by co-variance. Apart from this, biases on model and human error is also determined per structure. Surprisingly, each structures in South China Sea have more or less the same biases and covariances. This enabled a simpler methodology to be carried out, by just taking the same biases and covariances to calculate the reliability index for any other platform structures within South China Sea. You feel dizzy reading? try looking at below highly simplified flowchart.