Experimental study of flush end plate beam-to-CFST column composite joints with deconstructable bolted shear connectors

• Presents deconstructable and recyclable composite steel–concrete joint.
• Blind bolting allows for flush end plate to connect to CFST column.
• Joint has very favourable moment and rotation capacities.
• Rigid plastic design is applicable for this joint.
• Presents design guidance for practicing structural engineers.

This paper presents the results of static tests conducted on four full-scale flush end plate semi-rigid beam-to-column joints in a novel deconstructable and sustainable structural frame system. In this system, precast concrete slabs that are associated with reduced CO2 emissions during their manufacture are attached compositely to a steel beam using a novel method of shear connection that takes advantage of post-installed friction-grip bolted shear connectors and the composite steel beams are connected to concrete-filled steel tubular columns using flush end plates with blind bolts. The proposed structural system can be deconstructed at the end of its service life so that demolition waste is minimised and component recycling is maximised. In addition, application of precast slabs instead of cast in situ conventional concrete slabs can improve the quality of construction, reduce construction time and labour costs and lower the carbon footprint of the structure. The structural response of the beam-to-column joints is assessed under a monotonically increasing static load and the influence of the type of precast concrete slab and bolted shear connectors, as well as degree of shear connection, on the structural performance of this structural system are investigated. The test results show that these novel composite joints have credible rotation and moment capacities according to the recommendations of EC3 and EC4, and fracture of the joints occurs after development of substantial rotation.