Sustainable and Deconstructable Semi-Rigid Flush End Plate Composite Joints

Abstract

Composite construction is a popular and effective method of construction, exploiting the strengths of both reinforced concrete and structural steel in building construction in a complementary fashion. Within paradigms related to minimisation of emissions and maximisation of product recycling, these composite systems are problematic on a number of fronts. Firstly, common and traditional composite systems utilise ordinary Portland cement, which is known to be a very large contributor to atmospheric CO2 emissions. Secondly, for typical construction practices for steel-concrete composite systems, casting of the concrete onto profiled steel decking and conventional reinforcement placing are undertaken on-site, which is time consuming and labour intensive, and which can increase the cost of construction. Thirdly, composite action between the steel beam and the concrete slab is usually achieved by using headed shear studs. The headed shear studs connect these two elements permanently, which leads to much waste at the end of the service life of the building when it is demolished. This paper models a sustainable semi-rigid beam-to-column composite blind bolted connection with deconstructable bolted shear connectors using ABAQUS finite element (FE) software. In this “green” system, precast geopolymer concrete (GPC) slabs are attached compositely to the steel beam via pretensioned bolted shear connectors and the composite beam is connected to GPC-filled square columns using blind bolts. Non-linear material properties and non-linear geometric effects are considered in the simulation of a connection in hogging bending. Based on the FE modelling, using pretensioned bolts as shear connectors with GPC can improve the behaviour of semi-rigid flush end plate composite joints in terms of ductility and load capacity. Moreover, the behaviour of the bolted shear connectors should be considered in composite joint design as being very different to headed stud connectors.