Thematic Issue on Advances in Modeling, Analysis and Design of Steel Connections

All published articles of this journal are available on ScienceDirect.

EDITORIAL

Thematic Issue on Advances in Modeling, Analysis and Design of Steel Connections

Vincenzo Piluso Elide Nastri
Authors Info & Affiliations
The Open Construction and Building Technology Journal • 23 May 2018 • EDITORIAL • DOI: 10.2174/1874836801812010080

Modeling, analysis and design of steel connections between structural members are of primary importance in structural steel design, because the connections’ behavior significantly affects the response of steel structures under monotonic loading conditions, both in elastic and in plastic range, and exceptional impact loading conditions. In addition, also the seismic response of steel structures is strongly affected by the ultimate behavior of structural connections under cyclic loading conditions [1-3]. In particular, seismic design of steel structures is commonly carried out to assure the dissipation of the seismic input energy in the so-called “Dissipative Zones” which has to be properly detailed in order to assure wide and stable hysteresis loops. Once the yielding of non-dissipative structural members is avoided, connections play a role of paramount importance. In fact, they can be designed either as Full Strength (FS) or Partial Strength (PS). In the first case, the seismic input energy is dissipated by means of plastic cyclic excursions in structural members. In the second case, dissipation requires the plastic engagement of ductile connection components.

As it is well known, before the introduction of the concept of semi-rigidity [2, 4, 5], steel frame design was accomplished by properly considering a limit assumption regarding the joint behavior. Depending on the beam-to-column joint typology, it was either assumed that all the ends of the members converging in the joint are subjected to the same rotation and the same displacements or assumed that the joints are able to permit free rotations. The first case leads to continuous frames, while the second one to pinned frames. The application of the semi-rigidity concept requires the development of a general methodology working out in detail the provision of the rotational stiffness and the flexural resistance of joints. This resulted in a strong effort, in Europe more than in United States, which has led to complete definition and codification of the component method [2, 5]. This allows the analysis of actual semi-continuous structural systems, starting from the knowledge of geometrical and mechanical properties of beam-to-column joints.

The component method is essentially based on mechanical models constituted by the assembling of spring elements modeling the joint components. The non-linearity of the joint moment-rotation response is obtained starting from the inelastic constitutive laws adopted for the components. The method is suitable for modeling of any kind of joint, provided that the components are properly identified and their constitutive law is rightfully modeled.

This thematic issue is constituted by ten papers focused on topics that provide a significant contribution to the revision of code provisions. Currently, the revision of Structural Eurocodes is in progress and most of the authors of the papers selected for the thematic issue are involved in the Working Groups organized by CEN, the European Committee for Normalization, to support the Project Teams charged of the revision of Eurocodes. Most of the papers herein presented are, therefore, the result of a deep cooperation between researchers coming from different countries.

In particular, some papers are devoted to the influence of technological issues on the behavior of structural steel connections. Critical issues concerning the use of laser cutting technologies are investigated [6]. The application of the component method for the modeling of steel rack connections is analyzed [7]. The influence of the connections’ behavior on robustness and impact loading resistance is studied [8, 9]. Some critical issues regarding the role of structural steel connections in the seismic design of moment-resisting frames are analyzed [10-12]. In particular, the use of beam-to-column connections equipped with friction dampers is suggested [12] where the results obtained by means of different design strategies is presented. Reference is made to both MRFs designed according to Eurocode 8 and to MRFs designed according to the Theory of Plastic Mechanism Control [13-15]. The efficiency, during the service life of structures, of the innovative connections [16] analyzed [12] is strictly related to behavior of the material adopted for the friction pads [17] and to the long term behavior concerning the applied bolt preload [18].

With reference to connections equipped with friction dampers, experimental analysis and FE simulations devoted to assess the friction coefficients of several interfaces evaluating also their ability to withstand cyclic loading histories in terms of energy and strength degradation are presented [19]. The experimental work is with regard to eight different materials tested at low frequency applied on mild steel plates by means of thermal spray or by chemical bonding with the electroless nickel procedure. The experimental results have been used to validate finite element models able to simulate the behaviour of lap shear friction connections, showing the influence of different modelling approaches over the simulated data.

The accuracy in the prediction of the seismic response of steel structures is strongly affected by the modeling of the cyclic behavior joints. The critical issues regarding the calibration of the cyclic model parameter have been recently investigated [20], showing that the optimization of the calibration procedure requires the combined use of experimental results coming from both monotonic experimental tests and cyclic experimental tests. This critical issue has been emphasized by means of a comparison with the experimental results obtained by means of the pseudo-dynamic testing method.

In case of bolted connections, the most important joint components are modeled by means of an equivalent T-stub. For this reason, within elementary connections, bolted T-stubs are perhaps the most studied. FE analyses of bolted T-Stubs in the large deformation range are presented in this thematic issue [21].

Bolted extended end-plate connections are commonly used also for tubular members with rectangular and square hollow sections. The tension resistance of this type of splice can be analytically calculated by means of the component method. However, Eurocode 3 does not give effective rules to compute the effective length in the case of corner bolts. This critical issue is investigated [22] where the influence of corner bolts on the tensile resistance of the splice is analyzed by means of a a parametric study based on finite element simulations.

REFERENCES

1
Mazzolani FM, Piluso V. Theory and Design of Seismic Resistant Steel Frames. 1st Edition, London: E & FN Spon, An imprint of Chapman & Hall, 1996.
2
Faella C, Piluso V, Rizzano G. Structural Steel Semirigid Connections 1999.
3
Montuori R, Nastri E, Piluso V, Troisi M. Influence of connection typology on seismic response of MR-Frames with and without ‘set-backs’. Earthquake Eng Struct Dynam 2017; 46(1): 5-25.
4
Jaspart JP. Jaspart “Etude de la semi-rigidité des noeuds poutre-colonne et son influence sur la résistance et la stabilité des ossatures en acier” PhD Thesis, University of Liège, Liège 1991.
5
CEN (2005): “Eurocode 3: Design of Steel Structures - Part 1-8: Design of Joints”, EN 1993-1-8.
6
Zanon G, Bursi OS, Scardi P, D’Incau M, Raso S. High-cycle fatigue behaviour of S460N steel grade materials and bolted joints processed by laser cutting. Open Construction and Building Technology Journal 2018; 12
7
Gusella F, Orlando M, Thiele K, Vignoli A. Flexural capacity of steel rack connections via the component method. Open Construction and Building Technology Journal 2018; 12
8
Demonceau JF, Francavilla AB, Jaspart JP, Latour M, Rizzano G. On the robustness of earthquake-resistant moment-resistant frames: influence of innovative beam-to-column joints. Open Construction and Building Technology Journal 2018; 12
9
D’Antimo M, Demonceau JF, Latour M, Rizzano G, Jaspart JP. Preliminary Study on Beam-to-Column Joints Under Impact Loading. Open Construction and Building Technology Journal 2018; 12
10
Isaincu A, D’Aniello M, Stratan A. Implications of structural model on the design of steel moment resisting frames. Open Construction and Building Technology Journal 2018; 12
11
Tartaglia R, D’Aniello M, De Martino A. Ultimate performance of external end-plate bolted joints under column loss scenario accounting for the influence of the transverse beam. Open Construction and Building Technology Journal 2018; 12
12
D’Aniello M, Landolfo R, Montuori R, et al. Comparison between different design strategies for freedam frames: push-overs and IDA analyses 2018; 12
13
Montuori R, Nastri E, Piluso V. Advances in Theory of Plastic Mechanism Control: Closed Form Solution for MR-Frames. Earthquake Eng Struct Dynam 2015; 44(7): 1035-54.
14
Montuori R, Nastri E, Piluso V. Theory of Plastic Mechanism Control for MRF-EBF dual systems: Closed form solution. Eng Struct 2016; 118: 287-306.
15
Longo A, Montuori R, Piluso V. Moment frames-concentrically braced frames dual systems: Analysis of different design criteria. Struct Infrastruct Eng 2016; 12(1): 122-41.
16
Latour M, Piluso V, Rizzano G. Free from damage beam-to-column joints: Testing and design of DST connections with friction pads. Eng Struct 2015; 85: 219-33.
17
Ferrante Cavallaro G, Francavilla AB, Latour M, Piluso V, Rizzano G. Experimental behaviour of innovative thermal spray coating materials for FREEDAM joints. Compos, Part B Eng 2017; 115: 289-99.
18
Ferrante Cavallaro G, Latour M, Francavilla AB, Piluso V, Rizzano G. Standardised friction damper bolt assemblies time-related relaxation and installed tension variability. J Construct Steel Res 2018; 141: 145-55.
19
Latour M, Rizzano G, Piluso V, Zimbru M, D’Aniello M, De Martino A. Investigation on friction features of dissipative lap shear connections by means of experimental and numerical tests. Open Constr Build Technol J 2018; 12
20
Chisari C, Francavilla AB, Latour M, Piluso V, Rizzano G, Amadio C. Critical issues in parameter calibration of cyclic models for steel members. Eng Struct 2017; 132: 123-38.
21
Faralli AC, Latour M, Tan PJ, Rizzano G. Finite element analyses of bolted T-Stubs undergoing large displacements: A preliminary study Open Constr Building Technol J 2018; 12
22
Couchaux M, D’Aniello M, Falciano L, Faggiano B, Hjiaj M, Landolfo R. Finite element simulations on the tensile resistance of Bolted end-plate connections with tubular members. Open Constr Building Technol J 2018; 12