Final report for WP4.3: Enhancement of design methods ... - Upwind

UPWIND WP4: Offshore Support Structures and Foundations
Guideline
GL 2005 - Offshore
Wind
GL 2007 - Part 6 Offshore
Technology –
Chapter 2 Mobile Off-
shore Units
GL 2007 - Part 6 Offshore
Technology –
Chapter 2 Mobile Offshore
Units
Position Mooring
IEC 61400-3 - Guideline
for Offshore Wind
Turbines, Edition 1
ISO 19904 - Petroleum
and natural gas
industries - Floating
offshore structures -
Part 1: Monohulls,
semi submersibles
and spars
DNV-OS-C101 - Design
of Offshore Steel
Structures, General
(LRFD method)
DNV-OS-E301 -
Position Mooring
ISO 19901-7 – Petroleum
and natural gas
industries
Part 7: Stationkeeping
systems for floating
offshore structures
and mobile offshore
units.
1 VIM = vortex induced motions
Table 9.3: Guidelines: Safety Factors vs. Limit States
Limit State
ULS FLS SLS ALS
1.1 to
1.35
1,1 to
1,67
1.8 to
2.7
1,1 to
1,35
1.0 to
1.3
1.1 to
2.5
1.2 to
2.0
138
Return
period
1,00 1,00 n/a 50 years
1,0 to
1,35
1,00
n/a n/a
1,05 to
1.15
1.25 to
1.8
100 years
100 years
1,0 n/a n/a 50 years
Refers to DNV-OS-C101
1,00 1,00 1,00 100 years
n/a n/a
1.0 to
1.35
3.0 n/a 1.0
100 years
Remarks
Load safety factors
Metallic materials -
ULS: γM = 1,1;
FLS: 1,0 to 1,25,
depending on position
and importance
FRP materials –
ULS: 2,3 to 2,65
FLS: 1,485 to 2,35,
depending on manufacture
and type
Global safety
factors for working
stress design
Load safety factors
for LRFD
VIM* 1 may be neglected