A database of newly generated numerical strengths of planar and multiplanar joints was used to assess the current offshore design code methodologies and to derive a new design equation, based on the AWS ovalization parameter concept. Within defined geometric limits, the proposed equation has been found to be generally applicable to any axially loaded joint configuration, provided that the braces do not overlap. It negates the need for potentially subjective brace classification to be carried out and accounts fully for planar and multiplanar effects. The proposed equation is fully validated against the planar and multiplanar data in the screened database complied by MSL Engineering, and has been shown to have similar accuracy as the existing design equations advocated by ISO, yet have significantly wider validity.

1.
American Petroleum Institute, 1993, “
Recommended Practice Planning, Designing and Constructing Fixed Offshore Platforms
,” 20th ed., API RP2A, Section E, Connections.
2.
ISO, 1999, “
Petroleum and Natural Gas Industries-Offshore Structures-Part 2: Fixed Steel Structures
,” BS EN ISO 13819-2.
3.
Lee
,
M. M. K.
, and
Dexter
,
E. M.
, 1999, “
A New Capacity Equation for Axially Loaded MultiPlanar Tubular Joints in Offshore Structures
” Final report for Joint Industry Project, University of Wales Swansea.
4.
American Welding Society, 1996, “
ANSI/AWS D1.1 Structural Welding Code/Steel
,” Miami, FL.
5.
Wilmshurst
,
S. R.
, and
Lee
,
M. M. K.
, 1995, “
Static strength of multiplanar KK joints—a re-assessment of the database and estimation equations
Proceedings of the 14th International Offshore Mechanics and Arctic Engineering Conference
, Copenhagen, Vol.
III
, pp.
181
192
.
6.
Lalani
,
M.
, and
Bolt
,
H. M.
, 1989, “
Strength of multiplanar joints on offshore platforms
Proceedings of International Symposium on Tubular Structures
, Lappeenranta, Finland. Paper 2.04.
7.
Kurobane
,
Y.
, 1996, “
Ultimate behavior and design of multiplanar tubular joints
” in
Fatigue in Offshore Structures
, edited by
Rao
and
Dover
Oxford and IBH Publishing
.
8.
Lee
,
M. M. K.
, and
Dexter
,
E. M.
, 2004, “
Finite-Element Modeling of MultiPlanar Offshore Tubular Joints
,”
J. Offshore Mech. Arct. Eng.
0892-7219,
126
(February), pp.
120
128
.
9.
Yura
,
J. A.
,
Zettlemoyer
,
N.
, and
Edwards
,
I. F.
, 1980, “
Ultimate capacity equations for tubular joints
,”
Offshore Technology Conference 3690
, Houston, USA, pp.
113
126
.
10.
BOMEL
, 1996, “
Design and reassessment of tubular joints for offshore structures, Chapter 3: Static Strength
,” BOMEL report C6060R07.21.
11.
Dier
,
A. F.
,
Lalani
,
M.
, 1998, “
New code formulations for tubular joint static strength
,”
8th International Symposium on Tubular Structures
, Singapore, pp.
107
116
.
12.
Lee
,
M. M. K.
, and
Dexter
,
E. M.
, 1998, “
Ovalizing parameters for multiplanar tubular joints in offshore structures. Phase 2—Chord Ovalization—Effect of out-of-plane braces
” Civil Engineering Research Report CR/982/98, University of Wales Swansea.
13.
Lee
,
M. M. K.
, and
Dexter
,
E. M.
, 1998, “
Ovalizing parameters for multiplanar tubular joints in offshore structures. Phase 3—Chord Ovalization—Effect of in-plane braces
” Civil Engineering Research Report CR/990/98, University of Wales Swansea.
14.
Lee
,
M. M. K.
, and
Dexter
,
E. M.
, 1999, “
Ovalizing parameters for multiplanar tubular joints in offshore structures. Interim Report
,” Civil Engineering Research Report CR/995/99, University of Wales Swansea.
15.
Zettlemoyer
,
N.
, 1996, “
ISO harmonization of offshore guidance on strength of tubular joints
Proceedings of the 6th International Offshore and Polar Engineering Conference
, Los Angeles, USA.
16.
Lee
,
M. M. K.
,
Dexter
,
E. M.
, and
Kirkwood
,
M. G.
, 1995, “
Strength of moment loaded tubular T/Y joints in offshore platforms
,”
Struct. Eng.
1466-5123,
73
(
15
), pp.
239
246
.
17.
Gazzola
,
F.
,
Lee
,
M. M. K.
, and
Dexter
,
E. M.
, 2000, “
Design Equation for Overlap Tubular K joints under Axial Loading
,”
J. Struct. Eng.
0733-9445,
126
(
7
), pp.
798
808
.
18.
Baker
,
M. J.
, 1972, “
Variability in the strength of structural steels—a study in structural safety. Part 1: Material variability
” CIRIA Technical Note 44, September 1972, Pub. by Construction Industry Research and Information Association, London
19.
van der Vegte
,
G. J.
, 1995, “
The static strength of uniplanar and multiplanar tubular T and X joints
” PhD Thesis, Delft University of Technology, Netherlands.
You do not currently have access to this content.