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Enhanced Composite Behavior of CFST with Blind‐Bolted Connections under Tensile Pull‐out Tests
Author(s) -
Debnath Partha Pratim,
Chan TakMing
Publication year - 2021
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.1263
Subject(s) - embedment , ultimate tensile strength , structural engineering , materials science , stiffness , composite number , composite material , necking , tube (container) , engineering
The structural behavior and efficiency of high strength hollo‐bolts for moment connections in square CFST are evaluated. Investigations are carried out numerically to assess the composite behavior and tensile pull‐out capacity of the bolts. FE models were developed for existing experimental specimens and validated to further carry out parametric studies. It is observed that though the presence of concrete in hollow steel tube can effectively reduce the overall deformation of the tube, there has been very little enhancement in strength and stiffness for a normal hollo‐bolted connection under tensile loading. Whereas, with an enhanced bolt embedment length has led to considerable increase in strength and stiffness of the connection. The head of the elongated bolt anchored into the concrete core has also been useful to use the tensile strength of the bolts thus effectively using the bolt capacity. It is also observed that, the failure modes of the extended hollo‐bolt connections can be altered from concrete cone failure to bolt necking to tube wall yielding or a combination of two of them as per the strength arrangement of the components. Several parametric studies based on bolt length, bolt grade, concrete grade, tube wall thickness has been investigated and failure modes have been reported.