Four CNC machined, equal-thickness branch pipe intersections (dm/Dm = 1 and 0.746) have been tested under conditions of internal pressure, simulated seismic loading that induced resonant in-plane run pipe bending and, in one case, a superimposed gravity stress.
The manufacturing method and testing conditions are described and the behaviour of the branches is reported. The strain responses of the components show that ratchetting is clearly significant while the response moment data suggest that collapse may not be the failure mechanism under these loading conditions. Failure for all components occurred by cracks on the flanks in the branch hoop stress direction just above the junction.
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