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The presented study investigated the improvement of the seismic performance in steel buildings with semi-rigid connections with the Chevron bracing system. The seismic performance of such frames should be improved to prevent possible damages and failures. Accordingly, modelling Chevron bracing system was first done using openness software by adding zipper columns in the semi-rigid steel frames in three 5-, 8-, and 12-story structures as representatives of low-rise, medium-rise, and high-rise buildings, respectively. 84 semi-rigid frames were analyzed under seven near-fault records using dynamic non-linear time history analysis. The analysis of frames was done for both pinned and ductile connections and the case of removing and adding the zipper column. The results showed that the use of zipper columns in Chevron braces in the steel frames with pinned and semi-rigid connections controls both relative story displacement and maximum lateral story displacement. This effect is significant in frames with ductile connections.

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The possibility of progressive collapse as a result of seismic loading has attracted the attention of a number of researchers over the past few years. While using dual structural systems would be a rational choice in order to provide more resistance in this case, there is a lack of comprehensive study on the progressive collapse of these systems, especially when considering the removal of lateral load-bearing members as a part of a removal scenario.  This study investigated the potential for progressive collapse of steel structures with dual lateral force resisting systems subjected to seismic loading using the nonlinear dynamic analyses proposed in the Unified Facility Criteria (UFC) guideline. Toward this end, three different steel structures with 4-, 8-, and 12-story with intermediate moment frames (IMFs) and steel special concentrically braced frames (SCBFs) were examined under the effects of three far-fault ground motion records. For progressive collapse analysis, different removal scenarios including removing corner columns in different stories, as well as simultaneous removing columns and their adjacent bracing systems have been studied. The results indicated that considering seismic loads in progressive collapse has led to more critical conditions in structures by increasing the nodal vertical displacement of the top of the removed element as well as the demand-to-capacity ratios of adjacent columns. Further, it has been found that, among different removal scenarios, simultaneous removing columns and their adjacent bracing system from the structures subjected to three different ground motion records made them more susceptible to seismic progressive collapse.

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The purpose of the work is the evaluation of the behaviour of new wooden buildings with the installation of new dissipative wooden panels. Parametric analyses were conducted considering the use of the dissipative panel only, the system consisting of the panel coupled to an X-Lam wall and the use of steel braces. First, the sizing of the structures was carried out through a response spectrum dynamic analysis, to evaluate the conditions in which the panel could provide the best contribution. To this scope, a first parametric comparison was made considering a 9-storeys wooden building located in three sites in Italy, namely Bolzano, Fisciano and Calitri. Only for the Calitri location, which is characterized by the higher seismic intensity, the investigation was completed through a second parametric comparison which evaluated the contribution of the panel with the variation of the number of storeys with the scope of investigating if the panels are more suitable for high rise or low-rise buildings.  Finally, to check the dissipative behaviour of the structural system incremental dynamic analyses (IDA) and non-linear static analyses (pushover) were executed.

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This work formulates procedures and methods for the design, assembling, mechanical modeling, and experimental validation of a shake-table setup that has been in-house–built at the Laboratory of Structural Engineering of the University of Salerno. The analyzed shake table permits the experimental characterization of small- and medium-scale prototypes of seismic protection devices as well as the execution of experimental studies on mock-ups of earthquake-proof structures. The main features of this setup are the possibility of applying large lateral displacements histories of various shapes; the application of considerably high vertical loads; and the achievement of high peak velocities of the horizontal motion. Based on such targets, the design strategy presented in this work follows a different path compared with other desktop shake tables available on the market. The latter is most often scaled and built on requirements typical of conventional shake table modes (high accelerations, very low vertical loads, control in acceleration/velocity/displacements, etc.). The paper diffusely presents the approach followed by the development team at the University of Salerno – which may be of interest to research laboratories worldwide wishing to build similar setups – and explores the engineering potential of novel seismic protection devices. An experimental characterization test of a bioinspired seismic isolator that recently appeared in the literature is presented

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In this research, RBS effective parameters, on the seismic performance of beam-column connections have been investigated. In this study, finite element modelling analyses has been verified with a valid experimental specimen and the results are in good agreement. Ten models were numerically investigated. The investigated parameters are the various No. of IPB sections such as IPB120, IPB160, IPB200, and IPB240, changes in RBS beam cutting length (parameter b), changes in RBS beam cutting depth (parameter c), and changes in RBS beam cutting radius (parameter R). According to the numerical analysis, the moment-rotation curve, as well as the shape and stress distribution of the connection components, are examined for 10 different models. The results show that when the beam reaches the plastic moment area, the moment- rotation curve of the connection location is located in the elastic region. By decreasing the radius of the beam, the strength decreases and the energy dissipation decreases. Further, the results show that increasing parameter b (length of beam cutting), the strength and energy absorption capacity of the beam-column connection slightly decreases which is negligible. Therefore, with increasing parameter b, neither the RBS cutting depth, nor the RBS cutting radius has negative impact and it makes the initiative in executive and operational work to be higher and the executive restrictions to be less. The analysis of the distribution of von Mises stresses indicates the high ability of the beam to be connected with the reduced cross-section in the placement of the plastic joint tends in the reduced area of the beam flange in the area away from the connection.

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Under tension and compression, the wave crest and wave trough plastic zone of corrugated steel plate (CSP) have strong energy dissipation ability, but so far, the research on improving the energy dissipation capacity of building structure is very rare. To investigate behavior of the CSP, twelve models that consist of one to four folds with steel Q345B and Q235B, were simulated by using the finite element method. The numerical parameters varied in these models included geometries and materials of the corrugated steel plates. The results show that the CSP exhibits stable hysteretic behaviors, satisfactory energy dissipation capacities, large deformation and ductility capacity. Moreover, a method for estimating internal forces, yield displacement, yield load and stiffness of the CSP was derived and the derived equations provide reasonable predictions and shows agreement with theoretical values so can be used for future design. Based on the results, the parameter values of CSP that suitable for energy dissipation of building structures were suggested.

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In this paper, the free oscillations of a masonry panel made of unilateral No-Tension material are analysed, by adopting essentially the model proposed by Jacques Heyman. The aim of this analysis is to quantify the role of the elasticity in compression in the geometrically nonlinear dynamical response of Masonry-Like structures. Therefore, two unilateral models are considered: the first model assumes that the material is rigid in compression, the second one that the material is elastic in compression. Different levels of stiffness, in a range that covers realistic values of the Young modulus, are explored and the response of a simple panel subject to a fixed vertical compression and to different initial lateral disturbances are compared in order to estimate the effect of elasticity. As time histories for rigid and elastic panels display, the response of the rigid block is periodic and the response of the elastic block is quasi-periodic. In both cases the oscillation periods are visibly dependent on the amplitude. The periodicity of the elastic panels and its dependence on the amplitude is detectable also in the purely elastic phase, and is due to the physical nonlinearity induced by the unilateral material restrictions. The comparison between rigid and elastic time histories shows the main differences between the rigid and the elastic cases and allows to quantify the accuracy of the rocking-like assumption compared with the “harmonic type” simplification.

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Sudden failure of reinforced concrete or prestressed concrete bridges and viaducts occurred in Italy in the last few years due to brittle failure of Gerber supports subjected to degradation of material such as corrosion of steel bars. The danger of sudden and brittle failure is often due to pitting corrosion, loss of bond in steel bars and concrete crushing. In this paper, the risk of failure of Gerber supports in service condition and at ultimate state under vertical and lateral loads was investigated focusing on the consequences of pitting corrosion and loss of bond in steel bars. A simplified strut-and-tie model was developed to predict flexural response of Gerber supports including effects of corrosion of steel bars, loss of bond and concrete crushing due to the biaxial state of stresses. Several experimental studies regarding the flexural behavior of RC beams with Gerber supports were collected to validate the proposed model. The topic of this research is of particular interest for existing bridges with Gerber supports to be retrofitted or strengthened for seismic verification.

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