Flexural behaviour of composite steel–concrete beams utilising blind bolt shear connectors Sameera Wijesiri Pathirana a,⇑ , Brian Uy a , Olivia Mirza b , Xinqun Zhu b a Centre for Infrastructure Engineering and Safety, The University of New South Wales, Kensington, NSW 2052, Australia b Institute for Infrastructure Engineering, University of Western Sydney, Penrith, NSW 2751, Australia article info Article history: Received 2 February 2015 Revised 14 January 2016 Accepted 19 January 2016 Available online 27 February 2016 Keywords: Blind bolts Composite beams Demountable Rigid plastic analysis Finite element modelling Push-tests Shear-connectors abstract This paper investigates the feasibility of utilising blind bolts as shear connectors to develop demountable steel–concrete beams. The flexural behaviour of composite beams with two blind bolt types and welded stud connectors were experimentally investigated using full-scale beam specimens. A set of push-test specimens was tested based on the Eurocode 4 to compare the slip response of these connectors. The ulti- mate design loads of the test beams were calculated based on rigid plastic analysis (RPA) using the actual material properties. The beam experiments were simulated by using three-dimensional non-linear finite element models (FEMs). The material behaviour for concrete and steel in FEMs was described using con- crete damage plasticity and steel plasticity models respectively. The FEMs were validated by comparing the load–midspan deflection curves of the beam specimens obtained from the experiments and mod- elling. The effects of the concrete compressive strength, steel yield strength and the shear connection ratio on the flexural behaviour of the composite beams were studied by utilising the validated FEMs. The experimental and numerical results suggest that the ability of the blind bolts to achieve and maintain composite action in steel–concrete beams under flexural loading is comparable to that of the welded stud connectors. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction Age is one of many factors that affect the condition and perfor- mance of infrastructure in terms of meeting current and future loading requirements. Recent records show that existing ageing infrastructure needs improvements to prolong their service life and to resist future loading [1]. New initiatives in the way that infrastructure is designed can address the problems of condition and performance to which age contributes. Introducing demount- able composite beams is one such initiative. An increasing trend in investigating the feasibility of developing demountable compos- ite steel–concrete beams can be identified in the open literature. These studies have primarily focused on investigating different types of bolted shear connectors that suit for this purpose. This paper identifies two types of blind bolting systems that have the potential to be utilised as shear connectors to develop demount- able composite beams. Welded stud connectors are widely used in composite steel–concrete beams. The availability of detailed research [2–5,6] and standard design methods have made these connectors very popular in the construction industry. Some of the problems associated with welded stud connectors have also been attempted to be addressed over the last few decades. Researchers such as Kim and Jeong [7] and Kim et al. [8] addressed the welding quality, structural safety, constructability and cost-effectiveness of new connector types over welded stud connectors. However, composite beams with these connectors cannot be effortlessly deconstructed without damaging the steel and concrete components. As a result headed shear studs cannot be utilised to develop deconstructable beams. This problem can be overcome by utilising bolted connec- tors in composite steel–concrete beams. The two blind bolt types are referred to as BB1 and BB2 in this paper. Both are of M20 – grade 8.8 type bolts. The ability to be attached and detached from one side of a structure is one of the main aspects of these bolting systems that can be exploited to develop deconstructable composite beam systems. The advantages of these connectors are not limited to this aspect only. The bolt installation process that utilises power tools is much faster com- pared with the welded stud installation process. The installation process does not require heavy equipment to be run along the beams in which the bolts are fixed. Therefore the blind bolt instal- lation process is less complex and faster when compared with that of welded stud connectors. Blind bolts can also be tightened to a http://dx.doi.org/10.1016/j.engstruct.2016.01.057 0141-0296/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +61 405 362 563. E-mail address: i.wijesiripathirana@student.unsw.edu.au (S. Wijesiri Pathirana). Engineering Structures 114 (2016) 181–194 Contents lists available at ScienceDirect Engineering Structures journal homepage: www.elsevier.com/locate/engstruct