•Inclined loading of a re-entrant honeycomb structure induces a macro deformation stage.•New deformation stage consists of micro plateau-densification micro stages.•Increasing the loading angle ...causes the localisation of deformation.•Inclined loading causes a more compliant and ductile response.
The present study focuses on the deformation mechanisms of re-entrant honeycomb auxetic structures under inclined loading. An auxetic finite element prototype is compressed by a rigid plate during a static Riks analysis. Analysing the deformation response of the structure has revealed that a new transitional deformation stage emerges that highly restricts the elastic response. This new macro stage consists of consecutive micro stages of plateau-densification (yielding-hardening) that corresponds to a highly localised deformation mode, and alters the mechanical response in the following macro stages.
The design of offshore platforms in Indonesia generally uses Working Stress Design (WSD) method rather than Load and Resistance Factor Design (LRFD) method. Whereas the LRFD method produces designs ...that better describe real conditions with load and capacity factors. The load and capacity factors are obtained from consideration of the uncertainty or randomness of their values. One of the load factors used is the environmental load factor. The environmental load factor of LRFD method is obtained based on environmental characteristics not in Indonesian waters. There are differences in the environmental characteristics of each water. Uncertainty of environmental loads in the offshore platforms design is wave height, current velocities, and wind speed. To get a structure designed according to the characteristics of the waters in Indonesia, an environmental load factor is needed in accordance with the characteristics of Indonesian water. To achieve that, structural reliability analysis is needed. Structures reliabilty represents the possibility of the structure's performance criteria being met which is expressed by the reliability index. The reliability index of structures designed using the WSD method used as a reference for LRFD method. In this study, reliability analysis was carried out using the reserve strength ratio value from the pushover analysis on WSD method. The reliability index of the structure model is 4.10. This value is categorized as high reliability. This results can be used as a reference to determine the environmental load factor of Indonesian water in the future.
•Seismic fragility assessment of large-scale pile-supported wharf structures (PSWSs) is investigated.•Finite element modeling of PSWS with and without soil-pile interaction (SPI) is detailed with ...OpenSees computer program.•Pushover analysis strategy is utilized to classify the slight, moderate, and extensive damage states of the PSWS.•Effect of the SPI on seismic fragility of the PSWS is fully explored.
Seismic fragility curves are recognized as a useful tool for seismic performance assessment of pile-supported wharf structure (PSWS) exposed to seismic hazards. These curves quantify the probability of structural vulnerability against given ground motion parameters. Soil-pile interaction (SPI) is found to have a significant impact on seismic performance of pile-supported structures. In this study, in order to better understand the SPI effect, the seismic fragility of a large-scale PSWS located at the Port of Los Angeles Berth 100, USA, is fully investigated with and without considering SPI. Herein, the pushover analysis scheme is used for inferring the bound limits of seismic demands of this large-scale PSWS. Specifically, the purpose of pushover analysis is twofold: to identify which pile of the PSWS most likely suffers from seismic failure; and to determine the bound limits of seismic demands for estimation of fragility curves using the identified pile. A collection of ground motions with low and high moment magnitudes as well as small and large fault distances are selected for nonlinear time history analysis. The seismic demand models can be readily estimated from the data set of the intensity measure-seismic demand pairs by classical regression fitting. A comparison of fragility curves with and without SPI shows that SPI significantly influences the seismic fragility of the PSWS. For distinct damage states, the effect of SPI on the seismic fragilities of different piles can be totally different.
•Seismic performance of an ancient Neapolitan Masseria has been evaluated.•Three analysis types based on the three evaluation levels foreseen by the Italian Guidelines on Cultural Heritage have been ...applied to the case study building.•The analysis results, compared to each other, have shown the problems and the high vulnerability degree of the building.•The simplest evaluation level (EL1), compared to the most detailed one (EL3), has provided unconservative results in predicting the building seismic vulnerability.•Consolidation interventions have been designed and applied to the structural parts of the Masseria to improve its seismic behaviour.
In this paper, the seismic vulnerability appraisement, together with repairing and consolidation operations, of a masonry building with cultural and artistic value located in a small city near Naples are reported and discussed.
After a brief digression about the condition of historical and cultural Italian heritage damaged by seismic events and usually in poor condition due to a lack of maintenance, the case study is presented and described, providing not only historical news but also information about as-built status, spaces, functions and structural issues.
Once the principal failure modes affecting the building are identified, the estimation of seismic vulnerability is performed through three different evaluation levels given by the Italian Guidelines on Cultural Heritage.
The analysis results, compared to each other, have shown the problems and the high vulnerability degree of the building. Finally, according to the Italian Guidelines, the consolidation and upgrading interventions are proposed and described to ensure a safety use of the Masseria under seismic actions.
Unanchored steel storage tanks, commonly used in industrial facilities, can suffer damage during major earthquakes due to various failures. To better understand the seismic behaviour of such ...structures, a pushover-based seismic performance assessment of four tanks with varying slenderness ratios was performed. The emphasis was placed on understanding the relationship between engineering demand parameters, tank slenderness ratio, and wall geometrical imperfections, which were, however, imposed only to the lower course around the tank circumference to assess the upper limit of the effect of geometrical imperfections on the elephant-foot buckling (EFB). The findings reveal that axial compressive stress in the tank wall correlates with increased slenderness and geometrical imperfections. This implies that the axial compressive stress in the wall of broader tanks is relatively low, and the bulging at the bottom of the wall is mainly due to high hydrodynamic pressure and the resulting hoop stress. In contrast, the wall of slender tanks buckles primarily due to high axial stresses, leading to EFB. Through dynamic analysis, the study showed that the pushover analysis can underestimate the axial stress if the tank’s base plate is uplifted significantly before EFB occurs. The effect of the impact should thus be considered, especially in the case of slender tanks, because the base plate uplift mechanism is more pronounced than in broader tanks. Further research is needed for a more accurate prediction of the axial compressive stress in slender tanks. However, the safety margin in the post-yielding range is low because the yielding area of the tank wall rapidly increases after the occurrence of steel yielding. In the absence of a detailed 3D model of tanks, simplified formulas for estimating stresses in the tank wall may be used for the broader tanks but not for more slender tanks because of their inability to simulate the highly non-linear relationship between the ground motion intensity and the stresses observed in the plastic region of the tank wall.
•Slenderness and geometrical imperfection correlated to axial stress in tank walls..•Slender tanks buckle from axial stress, broader ones also due to high hoop stress.•Dynamic analysis revealed base plate impact triggers EFB, mainly in slender tanks..•Dynamic analysis including base plate-foundation impact necessitates further research..•Simplified formulas to evaluate slender tank stresses overestimate seismic capacity.
In this research, four types of concrete moment frame were designed with glass fiber reinforced polymer (GFRP) bars according to ACI 440.1R-15 and the seismic behavior was assessed using pushover ...analysis. The frames were three and five stories with two and three bays. A computer code was developed to calculate the amount of fiber reinforced polymer bars in beams of the frames. In order to evaluate nonlinear behavior in plastic hinge regions, sections of beams and columns were analyzed on the basis of moment-curvature diagram and also P-M interaction curve for columns. Performance levels of frames were determined considering ATC-40 criteria. Behavior of concrete moment frames reinforced with GFRP bars in terms of strength and ductility compared with frames reinforced with steel bars. Based on the results of analysis, it is concluded that frames reinforced with GFRP bars show higher strength than frames reinforced with steel bars under seismic loads. Besides, in comparison to five story moment frames, three story moment frames reinforced with GFRP bars provide higher ductility.
•Moment frames are designed with GFRP bars.•Pushover analysis is performed to assess seismic behavior of moment frames.•GFRP reinforced moment frames perform well in squat structures.•GFRP reinforced moment frame provide higher strength than steel reinforced moment frame.•GFRP reinforced frame is a suitable choice for frames demanding linear behavior.
•Non-linear static FE analyses on three shear walls and 1-room house prototype.•Experimentation on the same walls carried out at IIT Guwahati (India)•Isotropic elasto damaging 3D model to predict ...global behaviour and cracks.•Two-step homogenized FEM approach with fast ABAQUS implementation.•Good global and local match between homogenized FEM and experimental data.
In this study, three masonry shear wall prototypes with different opening configurations and a single room (URM) building constituted by the assemblage of the aforementioned walls are studied. Numerical results are compared with the experimental results carried out to validate the advanced numerical modelling. Two different Finite Element models are adopted for the numerical simulations; the first assumes that masonry behaves as a simple homogenous isotropic material exhibiting separate damage in tension and compression, the second relies on discretization of the individual walls and the whole building by means of elastic 8 noded elements and homogenized interfaces. Even though the first method provides acceptable predictions of the lateral load carrying capacity, damage criteria obtained are often not too close to those experimentally observed. Conversely, the second model exhibits the sufficient level of complexity that allows not only to accurately predict the global behavior, but also provides crack patterns very close to those experimentally obtained, so being considered a reliable tool for analysis of URM buildings and further to devise strengthening schemes to reduce their seismic vulnerability.
This work aims at analysing the design rules proposed for DC2 ductility class, introduced in the new prEN1998 draft, that is a new class intermediate between the low and hight ones. Simplified design ...rules aimed only at avoiding the so called soft-storey mechanism are proposed, because it is considered unnecessary to follow design rules that aim at the development of a global mechanism as occurs in the high ductility class. In particular, the design condition which is the statement of the DC2 design is based on an inequality that must be satisfied at all the storeys, which both does not consider the beam-column hierarchy criterion and does not possess any scientific background. This work aims to highlight the design rules proposed for MRFs in this new ductility class by carrying out a critical analysis. The attention is mainly focused on the soft-storey mitigation criterion and its application in a study case that represent the novelty of the paper.
