Introducing the TC-joint

The Innovation of the TC-joint, replaces the traditional welding in TKY joints delivering a structure with higher fatigue resistance, reduced steel volume, increased lifetime and reduced price. This innovation is developed at the faculty of Civil Engineering of the TU Delft. Since 2017 over 90 wrapped composite joints have been manufactured and tested on various sizes of joints at the Stevin lab. The results of these test conclude that the wrapped composite joint outperforms welds.

The improvement compared to welding is that the load is transferred through a dedicated composite wrap and not through the small surface of the weld. The brace members (diagonals) are bonded to the chord members (legs) through a coupling formed by composite wrapping. The wrap creates a sufficiently large internal bonding surface.

X45-type TC-joint at the Stevin lab
Modular jacket assembly without complex welds
Assembled jacket with TC-joints

TC-joint details

Superior Performance over welded joints

The substantial improvement of the fatigue resistance of the Circular Hollow Section (CHS) joints is achieved by 1) completely circumventing stress concentrations in steel CHS that normally are present due to local wall bending, and 2) avoiding residual stresses, embrittlement and notch effects due to welding.

Composite built-up of layers
Finite element model of a small-scale X90 joint

Prefabricated TC-joints

Double K, double Y and an X joint