Characterization of moment resisting I-beam to circular hollow section column connections resorting to passing-through plates

Abstract

Open-to-Circular Hollow Section (CHS) connections are highly encouraged nowadays in modern multistoried structures due to the extensive resistance provided by the CHS columns against high compression, tension as well as flexure in all directions, combined with their exceptional aesthetics. However, using more and more gusset plates or stiffeners to strengthen a conventional open-to-CHS connection causes economic disadvantage due to excessive welding quantities and substantial CHS chord yielding further limits any opportunity to exploit the full advantages offered by the open sections therefore minimizing its frequent application. However, if designed efficiently, the CHS connection can offer an extensive range of solutions which makes it an impeccable choice for the modern multi-storey structures. To that purpose, a "LASTEICON" solution is proposed in this paper investigating a "passing-through" concept, which is obtained by using laser cutting technology (LCT). Initially, a suitable moment resisting Plate-to-CHS-column connection is characterized through a detailed understanding of the relevant parameters, where the primary beams are connected at either side of the CHS column by two transverse and one longitudinal plate passing through the CHS column via laser cut slots. A detailed parametric study is conducted based on multiple Finite Element (FE) models primarily calibrated from an experimental campaign to understand the effect of each parameter and further verify and therefore establish the analytical assumptions to calculate the ultimate resistance of such connections. Finally a comprehensive design procedure is proposed to design such "passing-through" Plateto-CHS column connections. A short comparison study is also made with the conventional (direct weld) joints to highlight the advantages offered by this LASTEICON solution.

Laser Cut passing‐through Open‐to‐CHS Beam‐to‐Column Connections

“…Relevant geometrical specifications regarding the different components are provided in Table 1. Material properties for the numerical models were adopted according to the stress-strain relationship obtained from the experimental coupon tests [11]. A good agreement was found between the experimental and numerical results in terms of initial stiffness and ultimate resistance of the LASTEICON joints as shown by the force displacement curves plotted in Fig.…”

“…Under both load cases C3 provided a greater resistance than C4 with approximately same amount of steel and avoided complicated analytical calculations which might further support their preference from a designer's perspective. However, the C4 connection offered economic advantage as well as easy accommodation to design a four-way "passing-through" joint where a through beam is inserted through the CHS column in one direction and the plates can take care of the other [11].…”

“…Based on the outcomes of a detailed parametric study, discussed in a previous research publication [11], the force-transfer mechanisms were successfully identified for both configurations under different loading scenarios. For the LASTEICON configuration C3 under LC1, the flanges of the through I-beam started to yield just outside the CHS column prior to all other components of the connection configuration.…”

“…Some global structural solutions require a rather complicated asymmetric beam-to-column connection due to specific demands, possibly leading to the need of unsymmetrical connections. Few examples regarding such demands are provided in [11]. Although the C3 and C4 connections discussed in the previous section offer an efficient beam-to-column connection, they are not effective in those asymmetric conditions.…”

“…On the other hand, Laser Cutting Technology (LCT as shown in Fig. 1) offers several advantages compared to the mechanical cutting procedure by increasing the fatigue strength, reducing welding quantities, minimizing human error with computer-programmed automation and offering a swift fabrication process and thus provides an efficient solution to further investigate such "passing-through" connections [10,11]. Such significant advantages offered by the LCT and the aforementioned potential of the "passing-through" connections provided the necessary motivation towards this research study.…”