CJ255
Mechanical
- Jun 2, 2022
- 1
Hi,
I cannot wrap my head around the idea of reducing the maximum considered earthquake and to be used for designing structures.
SDS = 2/3*SMS & SD1 = 2/3*SM1
Normally, if we were to talk about safety factors, we would increase the expected loading to be designed. For example a lifting lug would be designed for 100 tonnes to lift a 50 tonnes object.
With this understanding, mainly I have 2 confusions
1. How could we reduce the maximum considered earthquake? Should we not design even above the maximum earthquake to achieve the maximum safety?
2. SDS and SD1 are arrived essentially from S1 and SS. If we can design by reducing the maximum considered earthquake, why did the USGS or other parties not just provide us with a lower S1/SS values?
I had reread this paragraph (Link) multiple times that seems to be explaining my confusion but I still could not grasp the idea of designing not based on the maximum earthquake considered.
Please enlighten me
I cannot wrap my head around the idea of reducing the maximum considered earthquake and to be used for designing structures.
SDS = 2/3*SMS & SD1 = 2/3*SM1
Normally, if we were to talk about safety factors, we would increase the expected loading to be designed. For example a lifting lug would be designed for 100 tonnes to lift a 50 tonnes object.
With this understanding, mainly I have 2 confusions
1. How could we reduce the maximum considered earthquake? Should we not design even above the maximum earthquake to achieve the maximum safety?
2. SDS and SD1 are arrived essentially from S1 and SS. If we can design by reducing the maximum considered earthquake, why did the USGS or other parties not just provide us with a lower S1/SS values?
I had reread this paragraph (Link) multiple times that seems to be explaining my confusion but I still could not grasp the idea of designing not based on the maximum earthquake considered.
Please enlighten me