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This paper aims to investigate the relationship between financial leverage and its main determinants in the context of SMEs in an emerging economy, such as the Chilean one. The investigation is based on the application of trade-off theory and pecking order theory. In this regard, the literature has amply highlighted that these two theories are more suitable for explaining the financial decisions of SMEs. We used a stratified sampling technique based on an economic criterion to identify the companies to analyze and develop the empirical analysis. The period investigated is three years and runs from 2016 to 2018. The research hypotheses were tested with a static fixed effects model (FE). The robustness checks validated the reliability of the model used. The results suggest that the size and tangibility of assets have a positive and statistically significant influence on debt. Conversely, profitability has a negative and statistically significant influence on leverage. The results of this research contribute to enriching the literature on the subject, providing empirical evidence of an economic context that has not yet been studied.

Background: In this paper, the influence of the Ramberg-Osgood exponent on the ultimate behaviour of the H-shaped (or I-shaped) aluminium beams subjected to non-uniform bending moment is investigated. Methods: In particular, the results of a wide parametric analysis recently carried out by the authors are herein exploited to point out the influence of the material properties. The flange slenderness, the flange-to-web slenderness ratio, and the non-dimensional shear length, accounting for the moment gradient, are the main non-dimensional parameters governing the ultimate resistance and the rotation capacity of H-shaped aluminium beams. Results: The influence of these parameters was investigated considering four different materials covering both low yielding-high hardening alloys and high yielding-low hardening alloys, which are characterised by significant differences in the values of the Ramberg-Osgood exponent of the stress-strain constitutive law of the material. Conclusion: Finally, empirical formulations for predicting the non-dimensional ultimate flexural strength and the plastic rotation capacity of H-section aluminium beams under moment gradient have been provided as a function of the Ramberg-Osgood exponent and all the above non-dimensional parameters.

Even though aluminium latticed domes are widely used as roofing structures in case of very large areas, few researchers have focused their attention on the influence of the structural details on the overall structural behaviour and on the development of models to account for such influence in the design process. Conversely, the most significant part of the research efforts is devoted to steel structures. In particular, the semi-rigidity of joint behaviour can play an essential role in the structural response. In this paper, the behaviour of bolted Aluminium Alloy Gusset (AAG) joints under axial force and bending moment is investigated by developing a mechanical model based on the application of the component method which is currently codified for the analysis of steel connections. The experimental tests available in the technical literature have been analysed to gain insight into the actual behaviour of AAG joints. The proposed mechanical model is presented, leading to the evaluation of both the moment-rotation curve and the axial force versus axial displacement curve of AAG joints. Finally, the analytical results obtained from the mechanical model herein proposed have been compared with the experimental results showing the accuracy of the component method also for the modelling of non-conventional connections such as those used in the case of aluminium alloy latticed domes.

The recent earthquakes have underlined the need for more advanced design philosophies able to avoid or reduce direct and indirect costs related to the occurrence of destructive seismic events. According to the traditional seismic design approach, under rare and very rare seismic events, the onset of damage to structural components is usually accepted. However, to address social expectations and the need for resilient buildings, recently, novel low-damage design philosophies have been proposed. These are based on the introduction of friction devices able to dissipate large amounts of energy with negligible damage. The cost of repair of these devices is typically only related to the re-tightening of bolts and, eventually, the substitution of friction shims. Noteworthy examples of this technology are the Sliding Hinge Joints (SHJs), developed at the University of Auckland, and the FREEDAM joints, developed at the University of Salerno within the framework of a homonym research project. In the last two decades, significant efforts have been devoted to understanding the seismic behaviour of such connections. The novelty of this work consists in investigating, for the first time, the seismic response of a large-scale building mock-up equipped with FREEDAM joints. The mock-up has been tested with a sequence of five accelerograms using the pseudo-dynamic testing method. The results have confirmed that FREEDAM connections provide large energy dissipation and rotation supply with almost no damage. The experimental results have been used to verify the accuracy of a numerical model developed with the software OpenSees, showing the capabilities of current simplified phenomenological modelling approaches in capturing the actual structural response.

The capacity of a structure can be assessed using inelastic analyses, requiring sophisticated numerical procedures such as pushover and incremental dynamic analyses. A simplified method for the evaluation of the seismic performance of steel Concentrically Braced Frames (CBFs) to be used in everyday practice and the immediate aftermath of an earthquake has been recently proposed. This method evaluates the capacity of an existing building employing an analytical trilinear model without resorting to any non-linear analysis. The proposed methodology has been set up through a large parametric analysis, carried out on 420 frames designed according to three different approaches: the first one is the Theory of Plastic Mechanism Control (TPMC), ensuring the design of structures showing global collapse mechanisms (GCBFs), the second one is based on the Eurocode 8 design requirements (SCBFs), and the third is a non-seismic design, based on a non-seismic design (OCBFs). In this paper, some examples of the application of this simplified methodology are proposed with references to structures that are supposed to exhibit global, partial, and soft storey mechanisms.

Stainless steel is an excellent construction material due to its high ductility, strain hardening, durability and aesthetic characteristics. To date, most studies on stainless steel have been devoted to understanding its mechanical properties and the behaviour of individual structural members and simple structures under monotonic loading. As a result, next versions of stainless steel codes, traditionally based on carbon steel codes, will enable efficient structural designs under static forces. However, advances related to the performance of stainless steel structural members under cyclic forces are still scarce, and there are no specific rules for the seismic design of stainless steel structures in Eurocode 8 in spite of the notable differences between this material and other steels. On this basis, an experimental programme on austenitic stainless steel hollow section elements subjected to cyclic loading has been recently conducted. A total of nine specimens with different local and member slenderness values were tested under cyclic bending around their major axis following a cantilever loading scheme. This paper describes the experimental set-up adopted for the tests, including the loading scheme and instrumentation, and discusses the load–displacement, moment–rotation, degradation of stiffness and energy dissipation values obtained in detail. In addition to providing fundamental information on the response of stainless steel members under cyclic loading, the description of the set-up reported in this paper will assist researchers in planning similar experimental programmes, while the results will serve as a reference to validate numerical analyses of stainless steel members and frames subjected to cyclic loading. The research was supported by the Spanish Ministry for the Economy and Competitiveness through the Project BIA2016-75678-R, AEI/FEDER, UE “Comportamiento estructural de pórticos de acero inoxidable. Seguridad frente a acciones accidentales de sismo y fuego”. The first author would also acknowledge the financial support received from the Spanish Ministry for Science, Innovation and Universities through the FPI-MINECO PhD fellowship Ref. BES-2017-082958.

The criteria and the formulations for predicting the rotational stiffness and the flexural resistance, under static loading conditions, of the most common connection typologies have been recently codified by Eurocode 3 in its Annex J (CEN, 1997) which is based on the so-called component approach. In order to extend the component approach to seismic applications, the modelling of the cyclic response of the joint components is necessary. Starting from the observation that the main sources of deformability and plastic deformation capacity of bolted connections can be modelled by means of an equivalent T-stub, an experimental program devoted to the cyclic response of the most important component of bolted connections has been planned aiming at the modelling of the cyclic force-displacement curve of bolted T-stubs. This paper presents a summary of the performed experimental tests and the description of the proposed models for predicting the cyclic behaviour of bolted T-stubs starting from the knowledge of their geometrical and mechanical properties.

The work is aimed at the prediction of the cyclic response of bolted beam-to-column joints starting from the knowledge of their geometrical and mechanical properties. To this scope a mechanical model is developed within the framework of the component approach already codified by Eurocode 3 for monotonic loadings.Accuracy of the developed mechanical model is investigated by means of the comparison between numerical and experimental results with reference to an experimental program carried out at Salerno University. The obtained results are encouraging about the possibility of extending the component approach to the prediction of the cyclic response of bolted connections.

In this paper, the results of an experimental analysis regarding beam-to-column joints equipped with friction dampers is presented. Even though the overall concept is not new, the connection structural detail and the friction pad material are different from previous proposals. In particular, the beam is connected to the column with a classical fixed T-stub fastening the upper flange and a friction damper located at the beam lower flange. The friction damper is composed of a stack of steel plates conceived to assure symmetrical friction. The friction pads are made of steel plates coated with thermally sprayed aluminium. The friction damper is designed in order to slide for a force level equal to or lower than the ratio between the nominal flexural resistance of the connected beam and the lever arm, i.e. the distance between the top T-stub and the friction damper. In this way, it is possible to obtain connections able to dissipate the seismic input energy almost without any damage to the steel elements, provided that all the joint components are designed with sufficient over-strength with respect to the actions corresponding to the friction damper sliding force. In this paper, such approach is validated reporting the results of an experimental campaign.

The ultimate behaviour of aluminium members subjected to uniform compression or bending is strongly influenced by local buckling effects which occur in the portions of the section during compression. In the current codes, the effective thickness method (ETM) is applied to evaluate the ultimate resistance of slender cross-sections affected by elastic local buckling. In this paper, a recent extension of ETM is presented to consider the local buckling effects in the elastic-plastic range and the interaction between the plate elements constituting the cross-section. The theoretical results obtained with this approach, applied to box-shaped aluminium members during compression or in bending, are compared with the experimental tests provided in the scientific literature. It is observed that the ETM is a valid and accurate tool for predicting the maximum resistance of box-shaped aluminium members during compression or in bending.

The work herein presented proposes an innovative approach to the use of friction dampers in seismic resistant steel structures. In fact, reference is made to dual systems where dissipative devices are located at beam ends, column bases and intersections of chevron braces. Friction devices are those investigated in the framework of the European Research Project “FREEDAM” (FREE from DAMage steel connections), supported by Research Found for Coal and Steel (RFCS). The aim of this project is the development of beam-to-column connections equipped with friction dampers showing low damage. Investigations concerning the prototype structure herein presented have been carried out to gain relevant information in the framework of the research project. Incremental Dynamic Analyses (IDA) are developed with reference to the maximum interstorey drift ratio, the maximum slippage velocity and the cumulative displacement, i.e. the travelled distance of the friction dampers. Moreover, the influence of the seismic intensity measure on the required friction damper stroke is investigated.

This work mainly aims to propose a new design procedure combining the benefits of the Performance-Based Plastic Design approach (PBPD) with a rigorous accounting of second-order effects. In fact, by exploiting the kinematic theorem of plastic collapse, second-order effects can be accounted for employing the concept of collapse mechanism equilibrium curve. The same tool constitutes the base of the Theory of Plastic Mechanism Control (TPMC) design approach. Besides, the paper reports a critical comparison between TPMC and PBPD, both having the scope to design structures exhibiting a collapse mechanism of global type. These two approaches are also compared with the refined PBPD where second-order effects are accounted for by the kinematic approach. Many steel moment resisting frames are designed according to PBPD, TPMC and refined PBPD and their performances have been compared on the bases of push-over analyses.

In this paper, the evaluation of the partial safety factors and of the overstrength coefficient needed to account for the influence of random material variability in the seismic design of dissipative connections equipped with friction dampers is reported. The computation of this coefficient has been carried out by means of a probabilistic approach taking into account different sources of randomness. These are the random variability of the friction coefficient of the pads equipping the damper and the randomness of the bolts preload due to the control of the tightening. Therefore, the aim of the work is the calibration of a local hierarchy criterion able to assure, with a given probability, that the friction connection is subjected to sliding while the beam end remain in elastic range. Finally, partial safety factors to be used in the design of these friction connections are proposed.

The experimental activity presented in this work intends to study in detail the cyclic behaviour of a set of three different friction shims preliminary selected in a previous experimental work regarding the behaviour of friction dampers of Sliding Hinge Joints (SHJs). These connections are able to dissipate seismic energy by means of friction through a proper application of capacity design principles. Their bending resistance is proportional to the slip resistance of a friction device which is usually installed at the bottom beam flange and can be governed controlling only two parameters: the friction coefficient and the clamping force of the high strength bolts. The main goal of the experimental campaign presented is to investigate the dependence of the friction coefficient on some of possible significant parameters. In particular, the 51 tests presented are devoted to evaluate the response of the interfaces taking into account the effect of the bolts preloading, the effect of the type of washers and the influence of the random material variability. In detail, the tests have been carried out with four different configurations of washers (with flat washers and disk springs), considering a possible range of values of the clamping forces (between 40% and 100% of the standard proof preload). The results of the experimental activity are reported in the paper proposing a possible definition of the values of the friction coefficients to be used in design and regression analyses of the experimental data of the slip tests to be used in simplified rigid-plastic modelling for seismic analyses.

In this study, both Canadian and European code provisions for steel concentrically braced frames (CBF) are discussed and issues addressing ductility classes for brace cross-sections, q factor value and brace configurations as covered in Eurocode 8 are presented. From comparison with the Canadian provisions it is concluded that beams and columns of CBFs designed according to Eurocode 8 could be under-design when braces perform in the inelastic range. A prototype 8-storey CBF building with multi-storey X-braces is designed and analysed in agreement with both code provisions. The nonlinear seismic responses are presented in terms of interstorey drift, residual interstorey drift and floor acceleration. It was concluded that both buildings are able to yield similar base shear, show similar floor acceleration while the European building undergoes larger residual interstorey drift.

Within European Research Project “FREEDAM” supported by RFCS a design procedure for MRFs equipped with friction dampers has been developed. In particular, beam-to-column joints are equipped with friction dampers located at the bottom flange level namely “FREEDAM” dampers. Therefore, all the connections are conceived in order to prevent structural damage. A prototype structure has been designed according to a design procedure assuring a collapse mechanism of global type whose name is Theory of Plastic Mechanism Control, and its seismic performances have been investigated by means of IDA analyses in a companion paper.

The sliding hinge joint is a type of low-damage seismic resistant connection equipped with a bolted friction damper at the bottom beam flange. To accurately control its flexural resistance, it is critical to govern the bolts' preload which depends on complex issues related to the installation procedure, and the short- and long-term phenomena. Despite the influence of these factors on the initial and life-time behaviour of bolts, currently, little information exists. Nevertheless, a statistical characterisation of the variability of the preloading force (initial and during the life-time) would be needed, in order to develop reliable design guidelines for these connections. Within this framework, this paper examines experimentally, the variability of the preloading force of European bolt assemblies applied in friction dampers, through continuously monitoring the preloading at installation over a period of time. This was done to analyse the accuracy of the standardised installation procedures and the rate of loss of the initial tension over time. The tests have evidenced a higher accuracy of the torque method, highlighting some criticisms of the combined method which, conversely, proved to be inaccurate as currently codified. The short- and mid-term tests have shown that the estimated loss after 50 years, in case of assemblies with normal washers or with European standardised disc springs is, on average, equal to 10% and 27%, respectively. Additionally, in all the cases, the greatest part of the total loss (≅ 70%) occurred in just 30 days, highlighting that time-dependent phenomena are mainly concentrated in the first days after tightening.