Monopile responses to monotonic and cyclic loading in undrained sand using 3D FE with SANISAND-MSu

Monopile response under undrained conditions in sand is gaining increasing interests owing to the recent development of offshore wind farms in seismic regions.Pore pressure evolution in liquefiable soil can significantly reduce the strength and stiffness of the soil which in turn affects the structural dynamic response.Several numerical models have been developed in the last two decades to enhance understanding of the mechanism of monopile-soil interaction with the existence of pore water pressure.In this study,the effects of geometry and static vertical load on monopile lateral response were studied using three-dimensional finite element methods that consider the existence of lateral cyclic load-induced pore water pressure.To achieve reliable simulation results of pore pressure development and pile displacement accumulation during cyclic loading,the simple anisotropic sand model with memory surface for undrained cyclic behavior of sand was adopted.For piles with the same diameter,a accumulated pile head displacement during lateral cyclic loading decreased linearly with increasing pile embedded length but increased with increasing eccentricity.Static vertical load had minor effects on pile cyclic lateral response.The distributions of mean effective stress and pore water pressure in the soil domain were presented.The pile reaction curve(cyclic soil reaction against pile defection)of the monopile was extracted.The numerical results aim to provide reference for optimized engineering design procedures.

Sternal Insufficiency Fractures of Post-menopausal Women:Retrospective Analysis of 17 Cases

Objective To retrospectively investigate the clinical characteristics of sternal insufficiency fractures(SIFs) of post-menopausal women.Methods Findings on the clinical presentation,associated diseases,and imaging of SIFs in 17 postmenopausal women admitted to our hospital between February 1999 and January 2009 were reported.Results Twelve patients complained of severe pain in their anterior chest.Other symptoms included cough(5 cases),dyspnoea(3 cases),breathlessness(3 cases),and wheeze(2 cases).Four patients had no discomfort.The sternums of 11 cases were tender to palpation.Seventeen patients had osteoporosis.Other associated diseases were chronic obstructive pulmonary disease(7 cases),rheumatoid arthritis(3 cases),systemic lupus erythematosus(1 case),asthma(1 case),and thoracic vertebral fracture(13 cases).Nine patients had received glucocorticoid treatment.The fractures were located in the body of the sternum in 15 patients,in the manubrium in 1 patient,and in the manubriosternal junction in 1 patient.Displaced fracture was present in 13 cases.Lateral radiography of the sternum showed a fracture line in 14 patients.In the remaining 3 cases,other imaging examinations such as bone scan,computed tomography or magnetic resonance imaging demonstrated the presence of a fracture.Conclusions Osteoporosis,glucocorticoid therapy,chronic obstructive pulmonary disease,and rheumatoid arthritis might be risk factors for SIFs.SIFs should be considered in the differential diagnosis of chest pain.