Full-size tubular nodes, either welded or of a composite cast steel/plate design, will be investigated as a logical continuation of previous studies on test bars. These tests will be carried out mainly under random sea state stress sequences in artificial sea-water. The aim is to investigate the transferability of the experimental results to real structures and to develop proposals for improvements to the design rules for offshore structures on basis of the results obtained so far on specimens and the results of proposed tests on tubular nodes. The research proposal has been coordinated with Det Norske Veritas and the German group of steel-makers, shipyards and research institutes. Conditions of the research programme: -specimen - K tubular nodes of about 1000/600/600 mm diameter - wall thickness - 30/20/20 mm -loading - tension-compression loading of the braces 180 phase-displaced -stress sequence - variable loading sea state stress (essentially); Wöhler tests (random samples) - material - FeE 355, FeE 460 or FeE 690 and some tubular nodes of cast steel/plate composite structure -environment - artificial sea-water.

The stress distribution in the critical cross-section prior to the occurrence and during the growth of the cracks will be determined by detailed strain measurements. The studies will also determine crack propagation with the earliest possible detection of crack initiation, especially in tests at low stress levels or with a high number of cycles. Further efforts will be made to propose state of the art dimensioning of offshore structures. The programme will cover the investigation of about 20 tubular nodes in total. For budgetary reasons the programme will be carried out in 2 phases.