Moment Resisting Connection with Curved Endplates: Behaviour Study

Andrej Mudrov,Antanas Šapalas,Kęstutis Urbonas,Gintas Šaučiuvėnas

doi:10.3390/app11041520

Andrej Mudrov, Antanas Šapalas + Show 2 more

Open Access

https://doi.org/10.3390/app11041520

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Journal: Applied Sciences	Publication Date: Feb 8, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Vilnius Gediminas Technical University

Abstract

This article provides a behaviour analysis of moment resisting joints with curved endplates. This is a new type of connection that can be used for joining steel beams to the circular hollow section (CHS) columns by means of bolts. Some researchers apply the Eurocode model without considering the differences in calculation schemes and assumptions, such as by using the general model of an equivalent T-stub in tension. Consequently, many of the existing behaviour studies are somewhat misleading, thus there is a need for further research. Apart from the absence of analytical methods that are devoted to predicting the initial stiffness and strength of the curved T-stub, other technical difficulties were encountered, such as gaps between the endplate and the column, as well as the initial pre-loading force of the bolts. In the previous studies, endplates were manufactured by rolling flat plates to the precise curvature which resulted in firm contact. In contrast, in this study, endplates were manufactured from a standard CHS tube, which led to significant initial gaps. Meanwhile, in terms of preloading force, it was found that it affected the moment resistance of the joint. This paper discusses problems associated with ongoing researches and presents experimental tests of the two connections. The obtained results were further used in the parametric finite element analysis (FEA) to determine the effect of the gaps and preloading force of the bolts on the moment resistance and initial rotational stiffness of the joint. The results indicate that the behaviour of curved plated connections is exceedingly complex and that the preloading force is the key factor, therefore, it should be controlled.

Highlights

Composite steel–concrete structures can be seen as a solution to the arising struggle with climate change [1,2,3,4] as they combine efficient use of materials with the robustness and ease of assembly, but their advantages are still not used widely enough
The main setback for composite structures is the lack of construction-wise and cost-effective joints. It is especially apparent in the design of frames with the circular concrete-filled steel tube (CFST) columns, which as a result of a superior confinement effect have greater compressive strength and deformation capacity than their square counterparts [5]
All joints failed in the tension zone either bytension punching shear

Summary

Introduction

Composite steel–concrete structures can be seen as a solution to the arising struggle with climate change [1,2,3,4] as they combine efficient use of materials with the robustness and ease of assembly, but their advantages are still not used widely enough. The main setback for composite structures is the lack of construction-wise and cost-effective joints It is especially apparent in the design of frames with the circular concrete-filled steel tube (CFST) columns, which as a result of a superior confinement effect have greater compressive strength and deformation capacity than their square counterparts [5]. A large-scale investigation of the new moment resisting joint with the curved endplates (Figure 1) has been in progress This includes experimental and numerical studies of the behaviour of the bolted endplates connection between a CFST column and a steel beam [10,11,12,13,14,15,16], as well as analysis of the connections between a composite beam and a stainless or carbon steel concrete-filled column [17,18,19,20,21,22].

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