Subloading surface plasticity model algorithm for 3D subsidence analyses above gas reservoirs

The coupled hydro-mechanical state in soils coming from consolidation/subsidence processes and undergoing plasticity phenomena is here evaluated by means of the subloading surface model. The most important feature of this theory is the abolition of the distinction between the elastic and plastic domain, as it happens in conventional elastoplastic models. This means that plastic deformations are generated whenever there is a change in stress and a smoother elasto-plastic transition is produced.The plasticity algorithm has been implemented in the PLASCON3D FE code (on the basis of a previous 2D version), coupling hydro-(thermo)-mechanical fields within a saturated porous medium (locally partially saturated at reservoir level due to the possible presence of a gas phase) subjected to external loads and water/gas withdrawals from deep layers (aquifers/reservoirs). The 3D model has been first calibrated and validated against examples taken from literature, and then subsidence analyses at regional scales due to gas extractions have been developed to predict the evolution of settlements and pore pressure in soils for long-term scenarios

Non-linear modelling, design and production of steel blast-resistant doors and windows

Numerical-experimental results are here described, derived from an innovative experience at both national and international level, related to modelling, designing and producing steel blast-resistant doors and windows. Their capability to sustain thermal loads due to fire hazards is additionally accounted for. The activity has been developed within a collaboration between Wellco S.p.A. and some researchers of the Department of Structural and Transportation Engineering of the University of Padua, Italy. The study has been conducted to define and characterize the non-linear response of a large number of doors and steel framed windows, with the objective of sustaining dynamic loads from explosive hazards of fixed magnitude, variable design and clearing times. The local overcome in the strength limit (with correspondent plastic response) and possible formation of plastic hinges has been critically discussed. Numerical models have allowed for refining first design sketches and subsequently understanding the real thermo-mechanical behaviour for the investigated structures. Experimental tests on typical steel doors at 1:1 scale have been performed at the Laboratory of Construction Materials of the same Department above. Such tests had the objective of “a-posteriori” verifying the correctness of the already available numerical results, validating the adopted procedures and correspondingly guaranteeing the doors’ structural efficiency even under dynamic loads higher than design ones