The study and development of recycling techniques for pavements is an increasing activity in engineering nowadays. This research line demands a more realistic characterization of the material properties with the aim of simulate the asphalt mixture’s response placed into a multilayered system over granular bases, under dynamic loads, considering also temperature variation or strength reduction for cyclic loads. In order to improve the current formulations, a new viscoplastic model has been developed assuming the strain rate dependency of the material’s response observed in the experimental tests. The strain rate variable affects in a significant way the Young modulus and the viscosity parameter of the model. According to this hypothesis a constitutive equations have been formulated. The mechanical variables involved have been calibrated according to experimental results, developing new expressions for the strain rate dependent parameters. The new viscoplastic model permits us to characterize the material’s response with a few mechanical values, easily obtained from standard laboratory tests. The results obtained show a good approximation to experimental laboratory curves for different rates of loading and temperatures. The model has been applied to simulate the response of a real flexible pavement structure conformed by two asphalt layers over two granular bases, that’s materials with different constitutive behaviors. Experimental tests in the recycled track have been made obtaining the horizontal strain evolution under dynamic load. Different loading rates and temperatures, as well as cracked and continuum pavement responses have been considered in the study. Strains were measured in the interface between the two asphalt layers and simulated using the here proposed model offering a fairly good approximation of the real response observed in the track, although the degree of variation even in the experimental curves is quite high. The results of this study represent a proper base for further developments in structural analysis of pavement layers, considering more complex phenomena, determinant in the long term material’s response, to develop a numerical tool for pavements’ design and lifetime prediction.

In this paper we analyze the capabilities of two numerical techniques based on DEM and FEM–DEM approaches for the simulation of fracture in shale rock caused by a pulse of pressure. We have studied the evolution of fracture in several fracture scenarios related to the initial stress state in the soil or the pressure pulse peak. Fracture length and type of failure have been taken as reference for validating the models. The results obtained show a good approximation to FEM results from the literature.

This article proposes an advanced nonlinear soil-structure interaction methodology, for the seismic analysis of a nuclear structure. To do so, a study is performed on a nuclear reinforced concrete structure considering the effects of the nonlinearity due to the sliding and rocking at the soil-structure interface, under a Beyond Design Basis Earthquake. A tridimensional numerical model based on the Finite Element Method is developed for the structure and the soil. The model of the structure considers composite materials to describe all the structural members, taking full advantage of the modelling capabilities of the finite element method. The soil layers are modelled assuming their degraded properties due to the propagation of the seismic ground motion. An innovative approach to achieve spectral matching at the surface of the FEM soil model after propagation from the bedrock has been successfully implemented. The seismic analysis on the structure has been performed by considering three hypotheses for the contact between soil and structure: fixed-base, fixed contact and sliding-rocking contact. Insights are provided after comparing floor spectra for the contact approaches assessed in this research, calculated at the systems and components’ locations at the nuclear structure. Finally, a statistical approach for the soil properties allows to study the effects of these uncertainties on the structural response.

Buildair S.A. has designed, manufactured and built an inflatable hangar (called hangar H75) for the aeronautical industry at Jeddah Airport, Kingdom of Saudi Arabia. H75 is the largest air-cell inflated structure ever built in the world, finally erected in July 2019. The structural analysis and design of the main body of the hangar has involved complex structural concepts due to the specificity of the structural elements employed, like membranes and straps that lead to a highly nonlinear mechanical problem, or the treatment of wind over the structure without a defined standard for inflatable structures. In this article, the structural concept and specificities of the structure are presented, as well as the design procedure for H75 based on numerical analysis, to fulfil the design requirements in terms of stress and deformation of the main body.