Modelling aspects of the seismic response of steel concentric braced frames

M. D’Aniello,G. La Manna Ambrosino,F. Portioli,R. Landolfo 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.5

This paper summarises the results of a numerical study on the non linear response of steel concentric braced frames under monotonic and cyclic loads, using force-based finite elements with section fibre discretisation. The first part of the study is addressed to analyse the single brace response. A parametric analysis was carried out and discussed to evaluate the accuracy of the model, examining the influence of the initial camber, the material modelling, the type of force-based element, the number of integration points and the number of fibers. The second part of the paper is concerned with the modelling issues of whole braced structures. The effectiveness of the modelling approach is verified against the nonlinear static and dynamic behaviour of different type of bracing configurations. The model sensitivity to brace-to-brace interaction and the capability of the model to mimic the response of complex bracing systems is analyzed. The influence of different approaches for modelling the inertia, the equivalent viscous damping and the brace hysteretic response on the overall structural response are also investigated. Finally, on the basis of the performed numerical study general modelling recommendations are proposed.

FEASIBILITY STUDY ON THE REDESIGN OF A METALLIC CAR HOOD BY USING COMPOSITE MATERIALS

Andrea Sellitto,Aniello Riccio,Giustino Magno,Giuseppe D’Errico,Gianluca Monsurrò,Alessandro Cozzolino 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.2

Nowadays, fuel consumption and exhaust emissions are topical issues in the automotive field, as environmental safeguard legislation constraints are going to get tougher. Indeed, one of the most efficient methods to contain fuel consumption and emissions is the weight reduction of the vehicle. In this paper, a feasibility study on the lightweight redesign of a metallic car hood by using composite materials is presented. In particular, two different configurations, employing composite laminates and sandwich structures, are investigated. The feasibility of each configuration is assessed in terms of stiffness specifications and pedestrian safety requirement. Hence, Head Injury Criteria are employed, according to regulations. Finally, an optimization procedure on the stacking sequence of the composite laminates is performed, to determine, among the feasible solutions, the one characterized by the minimum weight.

Seismic design rules for ductile Eurocode-compliant two-storey X concentrically braced frames

Silvia Costanzo,Mario D’Aniello,Raffaele Landolfo 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.3

Two-storey X-bracings are currently very popular in European practice, as respect to chevron and simple X bracings, owing to the advantages of reducing the bending demand in the brace-intercepted beams in V and inverted-V configurations and optimizing the design of gusset plate connections. However, rules for two-storey X braced frames are not clearly specified within current version of EN1998-1, thus leading to different interpretations of the code by designers. The research presented in this paper is addressed at investigating the seismic behaviour of two-storey X concentrically braced frames in order to revise the design rules within EN1998-1. Therefore, five different design criteria are discussed, and their effectiveness is investigated. With this aim, a comprehensive numerical parametric study is carried out considering a set of planar frames extracted from a set of structural archetypes that are representative of regular low, medium and high-rise buildings. The obtained results show that the proposed design criteria ensure satisfactory seismic performance.

Seismic behaviour of gravity load designed flush end-plate joints

David Cassiano,Mario D’Aniello,Carlos Rebelo 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.5

Flush end-plate (FEP) beam-to-column joints are commonly used for gravity load resisting parts in steel multistorey buildings. However, in seismic resisting structures FEP joints should also provide rotation capacity consistent with the global structural displacements. The current version of EN1993-1-8 recommends a criterion aiming at controlling the thickness of the end-plate in order to avoid brittle failure of the connection, which has been developed for monotonic loading conditions assuming elastic-perfectly plastic behaviour of the connection's components in line with the theory of the component method. Hence, contrary to the design philosophy of the hierarchy of resistances implemented in EN1998-1, the over strength and the hardening of the plastic components are not directly accounted for. In light of these considerations, this paper describes and discusses the results obtained from parametric finite element simulations aiming at investigating the moment-rotation response of FEP joints under cyclic actions. The influence of bolt diameter, thickness of end-plate, number of bolt rows and shape of beam profile on the joint response is discussed and design requirements are proposed to enhance the ductility of the joints.

Prediction of the flexural overstrength factor for steel beams using artificial neural network

Esra Mete Güneyisi,Mario D’Aniello,Raffaele Landolfo,Kasım Mermerdaş 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.3

The flexural behaviour of steel beams significantly affects the structural performance of the steel frame structures. In particular, the flexural overstrength (namely the ratio between the maximum bending moment and the plastic bending strength) that steel beams may experience is the key parameter affecting the seismic design of non-dissipative members in moment resisting frames. The aim of this study is to present a new formulation of flexural overstrength factor for steel beams by means of artificial neural network (NN). To achieve this purpose, a total of 141 experimental data samples from available literature have been collected in order to cover different cross-sectional typologies, namely I-H sections, rectangular and square hollow sections (RHS-SHS). Thus, two different data sets for I-H and RHS-SHS steel beams were formed. Nine critical prediction parameters were selected for the former while eight parameters were considered for the latter. These input variables used for the development of the prediction models are representative of the geometric properties of the sections, the mechanical properties of the material and the shear length of the steel beams. The prediction performance of the proposed NN model was also compared with the results obtained using an existing formulation derived from the gene expression modeling. The analysis of the results indicated that the proposed formulation provided a more reliable and accurate prediction capability of beam overstrength.

Finite element simulations on the ultimate response of extended stiffened end-plate joints

Roberto Tartaglia,Mario D’Aniello,Mariana Zimbru,Raffaele Landolfo 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.6

The design criteria and the corresponding performance levels characterize the response of extended stiffened end-plate beam-to-column joints. In order to guarantee a ductile behavior, hierarchy criteria should be adopted to enforce the plastic deformations in the ductile components of the joint. However, the effectiveness of thesecriteria can be impaired if the actual resistance of the end-plate material largely differs from the design value due to the potential activation of brittle failure modes of the bolt rows (e.g., occurrence of failure mode 3 in the place of mode 1 per bolt row). Also the number and the position of bolt rows directly affect the joint response. The presence of a bolt row in the center of the connection does not improve the strength of the joint under both gravity, wind and seismic loading, but it can modify the damage pattern of ductile connections, reducing the gap opening between the end-plate and the column face. On the other hand, the presence of a central bolt row can influence the capacity of the joint to resist the catenary actions developing under a column loss scenario, thus improving the joint robustness. Aiming at investigating the influence of these features on both the cyclic behavior and the response under column loss, a wide range of finite element analyses (FEAs) were performed and the main results are described and discussed in this paper.

Influence of seismic design rules on the robustness of steel moment resisting frames

David Cassiano,Mario D’Aniello,Carlos Rebelo,Raffaele Landolfo,Luís S. da Silva 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.3

Seismic design criteria allow enhancing the structural ductility and controlling the damage distribution. Therefore, detailing rules and design requirements given by current seismic codes might be also beneficial to improve the structural robustness. In this paper a comprehensive parametric study devoted to quantifying the effectiveness of seismic detailing for steel Moment Resisting Frames (MRF) in limiting the progressive collapse under column loss scenarios is presented and discussed. The overall structural performance was analysed through nonlinear static and dynamic analyses. With this regard the following cases were examined: (i) MRF structures designed for wind actions according to Eurocode 1; (ii) MRF structures designed for seismic actions according to Eurocode 8. The investigated parameters were (i) the number of storeys; (ii) the interstorey height; (iii) the span length; (iv) the building plan layout; and (v) the column loss scenario. Results show that structures designed according to capacity design principles are less robust than wind designed ones, provided that the connections have the same capacity threshold in both cases. In addition, the numerical outcomes show that both the number of elements above the removed column and stiffness of beams are the key parameters in arresting progressive collapse.