Abstract:
In order to improve the mechanical properties of active node in steel strut and the stability of the foundation in excavation engineering, a new type of active node, named BFW (bolt fasten wedge) was developed. The specimens were machined in factory according to the size 1:1. The bearing capacity experiments of the most unfavorable conditions under eccentric load and axial load were carried out. Meanwhile, the loading process of the specimens was simulated by ABAQUS software and the analysis of the mechanical properties of the active node were studied. The research results show that:1) at the early stage of loading, the specimens are in linear compression period, produce small displacements and are in good stability. Compared with the case under axial loads, the active nodes do not decline obviously in bearing capacities under eccentric loads, but their stiffness declines a little. Both the ultimate bearing capacity under axial load and that under eccentric load obtained through the tests are about 5 800 kN. 2) The ultimate failure form of the active node is the bolt fracture, so the bearing capacity of active node increases by increasing the strength force and the number of the bolts. 3) A deflection is generated along the eccentric direction under the eccentric load. In the condition of three eccentric loads, the stiffness of the active node is the largest under
X direction eccentric load. And it is the second largest under bidirectionally eccentric load, and the smallest under
Y direction eccentric load. The developed BFW active nodes are of reliable load capacity, good structural stability, so they may have broad application prospects.