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This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. This author accepted manuscript is made available following 24 month embargo from date of publication (October 2018) in accordance with the publisher’s archiving policy, Sand spits occur around the world with different shapes, dimensions and dynamics. While usually considered non-developable coastal features, development has taken place in several locations around the world, and because spits are often very dynamic, a better understanding of their behaviour and evolution is useful. Understanding their stability and morphological cycles can be used as a measure of the health of nearby beaches. The inter-annual and decadal morphological evolution of the beach spit at Tortugueros, on the Yucatan peninsula, Mexico, a re-entrant bay on the Isla del Carmen barrier system, is examined. Digitized information from satellite images and aerial photographs, covering a 31 year period, was used to compare the shoreline evolution with numerical results. The method used consists of the estimation of the wave breaking conditions and the evaluation of the cross and longshore energy flux. The time-averaged wave energy flux allows the estimation of the evolution of those morphological features. The shoreline changes are very dramatic, with rates of accretion up to 160 m yr-1 and erosion up to 196 m yr-1. The results of the comparative analysis show that Tortugueros beach is a resilient system in dynamic equilibrium, governed by the combination of the short period local marine climate of the area and large-scale weather cycles related to the El Niño and La Niña phenomena. The analysis presented in this paper is valid to describe the functioning and resilience of dynamic beach systems elsewhere, where the wave climate is known, based on the wave energy flux of the breaking waves.

The development of a new typology of enhanced steel reinforcing bars is presented, including aspects related to the industrial production process, microstructural and mechanical characterization of achieved samples, is presented. Dual-Phase steels, provided by a ductile ferrite matrix in which a second hard martensite phase is embedded, are widely used in the automotive sector due to their excellent performance in terms of ductility and durability. For the same reasons, Dual-Phase steels can represent a valid alternative to current steel reinforcements – mainly TempCore® – that, as highlighted by the current scientific literature, are affected by relevant decrease of ductility in case of corrosion attack. The present paper shows the results of investigations executed to produce DP bars in reinforcing steel industrial plants; the experimental characterization is provided too.

Due to the high number of discarded end-of-life tyres around the world every year, the use of rubber waste in concrete has been researched for some years in normal and high strength concrete. Rubcrete is a type of concrete which is similar to conventional concrete, but uses scrap tyre rubber as a partial substitution for mineral aggregates. Lightweight concrete is another type of concrete with the advantage of reducing the self-weight of the structure. Utilizing rubber waste in concrete as a replacement of fine and/or coarse aggregates to produce lightweight concrete is of great interest as it can potentially provide a ductile lightweight concrete. This study investigates the possibility of using rubber waste, lightweight expanded clay aggregate (LECA), or a combination of both, in producing ductile lightweight concrete at the material level as well as the structural level. Fourteen concrete mixes were produced with different rubber content as replacement of fine aggregate volume, and different rubber/LECA content as replacement of coarse aggregate volume. The pre-treatment of the rubber/LECA particles using water, cement/silica fume paste, and cement/silica fume solution was also investigated. Three reinforced concrete beams with 130 mm × 230 mm cross-section and 1000 mm length were made out of selected mixes and tested under cyclic loading. Several rheological and mechanical properties, and structural performance characteristics were measured and compared. The results indicated that the LECA performs better than coarse rubber as a replacement for concrete coarse aggregate. Pre-treatment of fine rubber by soaking in water for 24 h had no significant effect on concrete slump; however, it increased the compressive strength by 15%. Rubcrete had an insignificant effect on the general behaviour of the reinforced concrete beams. Using LECA-Rubcrete decreased the strength and ultimate displacement of the reinforced beam by 22% and 21%, respectively compared with the Rubcrete beam. Refereed/Peer-reviewed

The safety of buildings located in seismic zones is related to the proper design of both the structural and the non-structural components. In recent seismic events, the collapse of the non-structural parts clearly demonstrated how they may represent a risk not only for the life safety but also the majority of the economical losses. Light cladding panels are a common solution to built facades in framed systems with rigid infills, particularly in reinforced concrete structures with masonry walls. They are usually fixed to the supporting structures by means of plastic anchors through angle brackets. Within this context, an experimental campaign was carried out to investigate their behaviour under seismic action. Starting from dynamic tests on real size facades, a new test protocol was proposed for the assessment of plastic anchors for fixing facade claddings. The scope of the present paper is to provide a theoretical background for the aforementioned test protocol.

This paper is focused on the performance of a proposed scheme for seismic strengthening of shear deficient joints of 3D reinforced concrete (RC) corner beam-column connections. This technique is composed of a combination of GFRP sheets and a steel cage, and does not require perforating the existing concrete elements to anchor the FRP sheets. Two similar full-scale beam-column connections were made without any transverse reinforcement in their joint region. One of which was tested in its as-built condition, taken as the control specimen, while the other one was tested after strengthening. Seismic behaviour of these specimens was studied under a cyclic loading pattern imposed simultaneously with a constant column’s axial load. Comparison of the test results of these specimens revealed a noticeable improvement in the seismic response of the strengthened specimen. This achievement along with the application feasibility of this technique indicates the suitability of the proposed strengthening scheme for practical applications. Finally, the experimentally obtained joint shear strength of the control and retrofitted specimens are compared to the one estimated by the relationships of the softened strut-and-tie model and ACI-318, respectively. This comparison revealed a satisfactory prediction of joint shear strength for both specimens, the as-built and the strengthened one.

The challenge of this research consists in the first attempt to apply a dissipative friction connection to beam-to-column joints with semi-prefabricated Hybrid Steel-Trussed Concrete Beams (HSTCB) and RC pillars cast in-situ. Nowadays, HSTCBs are widely adopted in civil and industrial buildings and, therefore, it is required to evaluate their compliance with the capacity design criteria and their seismic energy dissipation capability. However, the design of the reinforcement of such beams usually lead to the adoption of large amount of steel within the panel zone which becomes potentially vulnerable to the effects of seismic cyclic actions and dramatically reduce the dissipation capacity of the entire structure. Therefore, the introduction of friction dampers in the HSTCB-to-column joints is investigated in order to evaluate the ability of the device in preventing the main structural elements from damage and limiting the cracking of the panel zone, thanks to the increase of the bending moment lever arm, which reduces the shear forces in the joint. Moreover, the proposed solution thoroughly investigates the connection between the friction device and the beam in order to ensure adequate strength and stiffness to the connection. The feasibility study is firstly conducted through the development of design criteria for the pre-dimensioning of the device and, successively, the proposed solution is validated through the generation of finite element models.

The accurate reproduction of the hysteretic behaviour exhibited by soils under cyclic loading is a crucial aspect of dynamic finite element analyses and is typically described using the concept of damping ratio. In this paper, a general algorithm is presented for assessing the damping ratio simulated by any constitutive model based on the registered behaviour in three-dimensional stress–strain space. A cyclic nonlinear elastic model capable of accurately reproducing a wide range of features of soil behaviour, including the variation of damping ratio with deformation level, is chosen to illustrate the capabilities of the proposed algorithm. The constitutive model is described and subsequently employed in two sets of finite element analyses, one involving the dynamic response of a sand deposit subjected to different types of motion and another focussing on the simulation of a footing subjected to cyclic vertical loading. The application of the presented algorithm provides insight into the processes through which energy is dissipated through hysteresis.

Hysteretic behaviour of corroded bars.Analytical modelling of post-yield buckling of corroded bars.Influence of corrosion on low-cyclic fatigue behaviour of reinforcing bars.Modelling the impact of corrosion on cyclic degradation of corroded bars. A new phenomenological hysteretic model for reinforcing bars with and without corrosion damage is presented. The model simulates buckling of reinforcement, deterioration in post-buckling compressive strength due to strain history and the impact of low-cycle fatigue on tension response. The model, for uncorroded reinforcing bars, is calibrated using data from numerical simulations and corrosion damage parameters are calibrated using experimental data. The model is evaluated using a comprehensive experimental data set, and the results show that the model is in a good agreement with the data.

Composite connections are defined as regions where composite beam frames into a steel column. A composite flange plate connection with web cleats is studied here since it is expected to give adequate seismic performance at minimum cost. A modification of the traditional flange plate connection, termed as stiffened flange plate connection is also suggested and its merits over the flange plate connection are assessed. Since in the flange plate and stiffened flange plate connections, the bolts are under shear and the problem of seat angle opening up under sagging moments is avoided, they are expected to perform equally well under sagging and hogging moments. To study the cyclic behaviour incremental amplitude cyclic tests were done on two interior joint sub-assemblages, one with a flange plate connection and the other with a stiffened flange plate connection as the means to transfer moment. The flange plate and stiffened flange plate connections showed adequate energy dissipation capacity and ductility to be used in seismically active regions. � 2013 Elsevier Ltd.

The bond–slip mechanism is one of the features that significantly controls the response as well as damage evolution of reinforced concrete structures when subjected to severe cyclic loadings, such as those induced by earthquakes. Its effect is particularly important in structures built with plain reinforcing bars. For a rigorous simulation of the response of existing RC structures, built mainly with plain bars, the bond–slip mechanism should be considered. However, the majority of the available concrete–steel bond numerical models were developed and calibrated for elements with deformed reinforcing bars. Moreover, the available experimental data on the cyclic behaviour of RC elements built with plain bars is still limited. In this framework, the objective of the present paper is to calibrate a numerical model based on results of a cyclic test performed on a two-span RC beam built with plain bars, which was collected from an existing structure. The numerical modelling was carried out with the nonlinear OpenSees software platform. Particular awareness was devoted to the bond–slip mechanism. The numerical results obtained with the calibrated nonlinear model are presented and compared with the experimental results. The consideration of the bond–slip effect in the numerical model was fundamental to achieve a good agreement between the numerical simulation and the test results.

Due to the inherent hardness and brittleness of WC-Co hard metals the determination of mechanical properties such as yield strength, ultimate strength and fatigue strength is a difficult task. A testing setup to determine stress-strain curves of hard metals under static and cyclic uniaxial compression and tension loading was developed. The investigated hard metal grades varied in WC grain size and Co-binder content ranging from 0.2 to 1.3 μm and 6 to 12 wt. %, respectively. The static stress-strain behaviour was analysed in uniaxial compression and tensile tests and specific material data like Young’s modulus and yield strength were determined. The cyclic stress-strain response along with the ratchetting behaviour as well as subcritical fatigue crack growth were investigated under uniaxial loading conditions. Fractographic studies of the fracture surfaces were conducted using scanning electron microscopy to identify the nature of crack origins. Based on Murakami’s concept the threshold of the stress intensity factor range at which fatigue crack growth starts from inhomogeneities was determined to be about 4.3, 6.2 and 9 MPa √ m at stress ratios of 0.1, −1 and −3 respectively.

A constitutive model developed for the simulation of the cyclic behaviour of interface elements is proposed. Its theoretical framework is fully based on the plasticity theory. Starting from an existing monotonic model, two new yield surfaces are introduced in order to include non-linear unloading/reloading behaviour in an accurate fashion. The motion of the unloading surfaces is controlled by a mixed hardening law and, by adopting appropriate evolution rules, it is possible to reproduce non-linear behaviour during unloading. Numerical results concerning the analysis of both uniaxial tests and masonry walls are presented and discussed as application and validation examples of the constitutive model.