Static Bearing Capacity Tests on Spatial DKT- Shaped Circular Hollow Section Tubular Intersecting Joints

To investigate the influence of geometric dimensions and eccentricity on the stress-strain distribution， mechanical properties， failure modes， and ultimate bearing capacity of spatial DKT-shaped circular hollow section tubular intersecting joints， experimental studies and finite element analysis were conducted on three non-eccentric and two eccentric spatial DKT-shaped circular hollow section tubular intersecting joints. Through experimental study， the bearing capacity， deformation， and failure modes of the five spatial DKT-shaped circular hollow section tubular intersecting joint specimens were compared. Finite element simulations were conducted on the specimens using the finite element analysis software. The analysis results of bearing capacity， deformation， etc. were in good agreement with the test results. The results of the study showed that： when the in-plane angle between the brace and the chord increased from 30°（SJ1） to 60°（SJ3）， the joint bearing capacity decreased by approximately 4.88%； when the eccentricity increased to 88 mm（SJ4） and 110 mm（SJ5）， the bearing capacity decreased by 26.7% and 17.9%， respectively， compared with that of the non-eccentric joint （SJ3）. Through the analysis of stress and strain distributions obtained from tests and finite element analysis， it was found that when the joint reaches its ultimate bearing capacity， the connection area between the brace and the chord enters a plastic state； however， the failure of the joint is not governed by section plasticity， but rather by deformation control.