Study on anti-progressive collapse performance of assembled steel frame joints with Z-type cantilever beam splices

Abstract

A new type of joint with Z-type cantilever beam splices was proposed for assembled steel frame structures in this study. The basic specimen was designed based on the theory of bolt sliding energy dissipation, and three groups of specimens were obtained by changing key parameters. That is, there is no section weakening (Z-BASE), flange weakening of cantilever beam near column (Z-RBS), flange weakening of steel beam near splicing (Z-SRBS), and flange and web weakening of steel beam near splicing (Z-RBS-RWS). The effects of reducing beam section and beam web on the anti-progressive collapse performance of assembled steel frame joints with Z-type cantilever beam splices were studied. The test results were described in detail in general behavior, failure modes, deflection shapes, limit displacements, and resistance mechanisms. According to the test results, specimen Z-RBS had the best anti-progressive collapse performance, and its ultimate load and initial failure displacement were 116% and 114% higher than specimen Z-BASE, respectively. In addition, specimens Z-SRBS and Z-RBS-RWS also had better anti-progressive collapse performance than specimen Z-BASE. Moreover, the validity of the results was verified and study parameters were analyzed using ABAQUS. The assembled steel frame joints with Z-type cantilever beam splices had better anti-progressive collapse performance than ordinary cantilever beam assembled steel frame joints. And the bearing capacity and ductility of the structure were improved by increasing the distance from the cantilever beam splices to the failed middle column, a, and reducing the aperture of the bolt on the cantilever beam splices, b. However, reducing the number of bolts on the cantilever beam splices, c, exhibited the opposite influence. Based on the above comparisons, the proposed design details of assembled steel frame joints with Z-type cantilever beam splices are given.