Soil-Structure Interaction Considerations in Seismic Design for Deep Bridge Foundations

Soil-structure interaction (SSI) effects when evaluating seismic response of deep bridge foundations to earthquake loading are complex and sometimes intriguing. The main factors in soil-structure interaction considerations that govern the seismic design of deep bridge foundations include interactive inertial forces, soil-pile kinematic forces in particular in liquefied sands or strain-softened clays due to seismic shaking, and the loss of soil support to the piles due to soil liquefaction. To evaluate these three key effects for the design of bridge foundations in seismic regions, soil-structure interaction analyses are normally required. Such analyses become more complex when soils supporting the bridge foundations are liquefiable and the effects of soil liquefaction need to be considered. Soil-structure interaction effects are routinely considered in seismic design, however, the way of incorporating the effects of soil liquefaction can be different depending on the project specific seismic design requirements and performance criteria. This paper explores how soil-structure interaction analyses have been incorporated into the design of three bridges in the seismically active Greater Vancouver area

Design for end-user acceptance: requirements for work clothing for fishermen in mediterranean and northern fishing grounds

Fishing is one of the most dangerous occupations, and as many as 24,000 fishermen around the world suffer fatal injuries or drowning at sea every year. Although fishermen in the European fishing fleet work in harsh and dangerous environments, many fishermen do not use personal protective clothing and buoyancy aids due to reduced work comfort and poor functionality. This emphasizes the importance of designing work clothing and personal protective equipment (PPE) with functionality that matches the fishermen’s needs. The aim of this study was to identify the requirements for work clothing in terms of comfort, protection, and safety for fishermen operating in northern fishing grounds and in the Mediterranean. Furthermore, we investigated whether fishermen in the Mediterranean prioritize workclothing requirements differently from fishermen in northern fishing grounds. Interviews and observations of fishermen provided us with the requirements for work clothing for fishermen. A questionnaire was then distributed to a selection of European fishermen. The study showed that fishermen operating in the Mediterranean prioritized their requirements differently from fishermen in northern fishing grounds. There was good agreement on requirements regarding work comfort. Safety requirements, such as integrated buoyancy, were ranked as less important by the Mediterranean fishermen compared to fishermen in northern fishing grounds. The results of this study provide a basis for the development of work clothing and PPE for fishermen. Work clothing and PPE that fulfil the requirements are likely to obtain end-user acceptance and thus improve safety for fishermen at sea

Polyunsaturated fatty acids for the primary and secondary prevention of cardiovascular disease

Background: Evidence on the health effects of total polyunsaturated fatty acids (PUFA) is equivocal. Fish oils are rich in omega-3 PUFA and plant oils in omega-6 PUFA. Evidence suggests increasing PUFA-rich foods, supplements or supplemented foods can reduce serum cholesterol, but may increase body weight, so overall cardiovascular effects are unclear. Objectives: To assess effects of increasing PUFA intake on cardiovascular disease (CVD) and all-cause mortality in adults. Search method: We searched CENTRAL, MEDLINE and Embase to April 2017 and ClinicalTrials.com and World Health Organization International Clinical Trials Registry Platform to September 2016, without language restrictions. We checked trials included in relevant systematic reviews. Selection criteria: We included randomised controlled trials (RCTs) comparing higher with lower PUFA intakes in adults with or without CVD that assessed effects over ≥12 months. We included full-text, abstracts, trials registry entries and unpublished data. Outcomes were all-cause mortality, CVD mortality and events, risk factors (blood lipids, adiposity, blood pressure), and adverse events. We excluded trials where we could not separate effects of PUFA intake from other dietary, lifestyle or medication interventions. Data collection and analysis: Two authors independently screened titles/abstracts, assessed trials for inclusion, extracted data, and assessed risk of bias. We wrote to authors of included studies for further data. Meta-analyses used random-effects analysis, sensitivity analyses included fixed-effects and limiting to low summary risk of bias. We assessed GRADE quality of evidence. Main result: We included 49 RCTs randomising 24,272 participants, with duration of one to eight years. Twelve included trials were at low summary risk of bias, 33 recruited participants without cardiovascular disease. Baseline PUFA intake was unclear in most trials, but 3.9% to 8% of total energy intake where reported. Most trials gave supplemental capsules, but eight gave dietary advice, eight gave supplemental foods such as nuts or margarine, and three used a combination of methods to increase PUFA. Increasing PUFA intake probably has little or no effect on all-cause mortality (risk 3.4% vs 3.3% in primary prevention, 11.7% vs 11.5% in secondary prevention, risk ratio (RR) 0.98, 95% confidence interval (CI) 0.89 to 1.07, 24 trials in 19290 participants), but probably reduces risk of CVD events from 5.8% to 4.9% in primary prevention, 23.3% to 20.8% in secondary prevention (RR 0.89, 95% CI 0.79 to 1.01, 20 trials in 17,073 participants), both moderate quality evidence. Increasing PUFA may reduce risk of CHD events from 13.4% to 7.1% primary prevention, 14.3% to 13.7% secondary prevention (RR 0.87, 95% CI 0.72 to 1.06, 15 trials, 10,076 participants), CHD death (5.2% to 4.4% primary prevention, 6.8% to 6.1% secondary prevention, RR 0.91, 95% CI 0.78 to 1.06, 9 trials, 8810 participants) and may slightly reduce stroke risk (2.1% to 1.5% primary prevention, RR 0.91, 95% CI 0.58 to 1.44, 11 trials, 14,742 participants), but has little or no effect on cardiovascular mortality (RR 1.02, 95% CI 0.82 to 1.26, I2 31%, 16 trials, 15,107 participants) all low quality evidence. Effects of increasing PUFA on major adverse cardiac and cerebrovascular events and atrial fibrillation are unclear as evidence is of very low quality. Event outcomes were all downgraded for indirectness, as most events occurred in men in westernised countries. Increasing PUFA intake reduces total cholesterol (MD -0.12 mmol/L, 95% CI -0.23 to -0.02, I2 79%, 8072 participants, 26 trials) and probably decreases triglycerides (TG, MD -0.12 mmol/L, 95% CI -0.20 to -0.04, I2 50%, 3905 participants, 20 trials), but has little or no effect on HDL (MD -0.01 mmol/L, 95% CI -0.02 to 0.01, I2 0%, 4674 participants, 18 trials) and LDL (MD -0.01 mmol/L, 95% CI -0.09 to 0.06, I2 44%, 3362 participants, 15 trials). Increasing PUFA probably causes slight weight gain (MD 0.76 kg, 95% CI 0.34 to 1.19, I2 59%, 7100 participants, 12 trials). Effects of increasing PUFA on serious adverse events such as pulmonary embolism and bleeding are unclear as the evidence is of very low quality. Authors' conclusions: Increasing PUFA intake probably reduces risk of CVD events, may reduce risk of CHD events and CHD mortality,and may slightly reduce stroke risk, but has little or no effect on all-cause or CVD mortality. The mechanism may be via lipid reduction, but increasing PUFA probably slightly increases weight

Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease

Background: Researchers have suggested that omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this. Objectives: To assess effects of increased intake of fish- and plant-based omega-3 for all-cause mortality, cardiovascular (CVD) events, adiposity and lipids. Search methods: We searched CENTRAL, MEDLINE and Embase to April 2017, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to September 2016, with no language restrictions. We handsearched systematic review references and bibliographies and contacted authors. Selection criteria: We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation and/or advice to increase LCn3 or ALA intake versus usual or lower intake. Data collection and analysis: Two review authors independently assessed studies for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression. Main results: We included 79 RCTs (112,059 participants) in this review update and found that 25 were at low summary risk of bias. Trials were of 12 to 72 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most studies assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet. Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (RR 0.98, 95% CI 0.90 to 1.03, 92,653 participants; 8189 deaths in 39 trials, high-quality evidence), cardiovascular mortality (RR 0.95, 95% CI 0.87 to 1.03, 67,772 participants; 4544 CVD deaths in 25 RCTs), cardiovascular events (RR 0.99, 95% CI 0.94 to 1.04, 90,378 participants; 14,737 people experienced events in 38 trials, high-quality evidence), coronary heart disease (CHD) mortality (RR 0.93, 95% CI 0.79 to 1.09, 73,491 participants; 1596 CHD deaths in 21 RCTs), stroke (RR 1.06, 95% CI 0.96 to 1.16, 89,358 participants; 1822 strokes in 28 trials) or arrhythmia (RR 0.97, 95% CI 0.90 to 1.05, 53,796 participants; 3788 people experienced arrhythmia in 28 RCTs). There was a suggestion that LCn3 reduced CHD events (RR 0.93, 95% CI 0.88 to 0.97, 84,301 participants; 5469 people experienced CHD events in 28 RCTs); however, this was not maintained in sensitivity analyses - LCn3 probably makes little or no difference to CHD event risk. All evidence was of moderate GRADE quality, except as noted. Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20, 19,327 participants; 459 deaths, 5 RCTs),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25, 18,619 participants; 219 cardiovascular deaths, 4 RCTs), and it may make little or no difference to CHD events (RR 1.00, 95% CI 0.80 to 1.22, 19,061 participants, 397 CHD events, 4 RCTs, low-quality evidence). However, increased ALA may slightly reduce risk of cardiovascular events (from 4.8% to 4.7%, RR 0.95, 95% CI 0.83 to 1.07, 19,327 participants; 884 CVD events, 5 RCTs, low-quality evidence), and probably reduces risk of CHD mortality (1.1% to 1.0%, RR 0.95, 95% CI 0.72 to 1.26, 18,353 participants; 193 CHD deaths, 3 RCTs), and arrhythmia (3.3% to 2.6%, RR 0.79, 95% CI 0.57 to 1.10, 4,837 participants; 141 events, 1 RCT). Effects on stroke are unclear. Sensitivity analysis retaining only trials at low summary risk of bias moved effect sizes towards the null (RR 1.0) for all LCn3 primary outcomes except arrhythmias, but for most ALA outcomes, effect sizes moved to suggest protection. LCn3 funnel plots suggested that adding in missing studies/results would move effect sizes towards null for most primary outcomes. There were no dose or duration effects in subgrouping or meta-regression. There was no evidence that increasing LCn3 or ALA altered serious adverse events, adiposity or lipids, although LCn3 slightly reduced triglycerides and increased HDL. ALA probably reduces HDL (high- or moderate-quality evidence). Authors' conclusions: This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. Low-quality evidence suggests ALA may slightly reduce CVD event risk, CHD mortality and arrhythmia

A hybrid effective stress – total stress procedure for analyzing soil embankments subjected to potential liquefaction and flow

Seismic design of major civil structures (bridges, dams and embankments) is moving increasingly towards using performance design methodologies which require determination of earthquake induced movements. Development of these numerical design tools and procedures for use in engineering practice for estimating the earthquake induced ground deformations of potentially liquefiable soil is the topic of this dissertation. Fully coupled effective stress numerical analyses procedures developed at the University of British Columbia (UBC) were used to simulate field and centrifuge test case histories. These analyses can offer considerable insight, but due to the complexity of the problem and variability of the parameters involved, there is considerable uncertainty. The author, therefore, recommends that the relatively new state-of-the-art effective stress analyses should be augmented by carrying out an additional analysis compatible with conventional design processes. This latter analysis uses published post-liquefaction “residual” soil strengths derived from back-analysis of field case histories by others. The developed design methodology uses the effective stress (UBCSAND) soil constitutive model for dynamic analyses, and empirical “residual” post-liquefaction soil strengths for a post-shaking total stress static analysis. In the proposed approach, the effective stress dynamic analysis is used to determine zones of liquefaction, to quantify earthquake induced deformations, and to provide overall insight. The post-shaking total stress static analysis, with “residual” strength parameters used in elements which liquefied, is carried out to capture the effects of complex stratigraphy and localization that may be missed by the effective stress model. Calibration and validation of the UBCSAND model was undertaken by comparing the model with field case histories and laboratory simple shear, shake table, and centrifuge tests. The measured response of some centrifuge tests being used for validation was indicative of the centrifuge model not being fully saturated. This was problematic as P-wave measurements within the centrifuge model suggested full saturation. A series of triaxial tests with P-wave measurements was carried out. These tests, and the numerical modeling of them, showed that high P-wave velocities were not always indicative of full saturation and they provided a logical explanation for the observed centrifuge response.Applied Science, Faculty ofCivil Engineering, Department ofGraduat

Vitamin D Uptake in Patients Treated with a High-Dosed Purified Omega-3 Compound in a Randomized Clinical Trial Following an Acute Myocardial Infarction

BackgroundFish is the natural dietary source of vitamin D. Reports on the influence of purified omega-3 fatty acids on its uptake are scarce.ObjectivesWe investigated the impact of a purified high-dose omega-3 compound compared to corn oil on 25-hydroxyvitamin D [25(OH)D] levels following an acute myocardial infarction.Methods228 patients were randomized 1:1 to receive a daily dose of either 4 g omega-3 (OMACOR®) or an equal dose of corn oil, administered double-blindly for 12 months. Total omega-3 and omega-6 measurements were available in 40 randomly picked patients.ResultsThere was no significant intergroup difference in 25(OH)D changes at 12 months follow-up (p = 0.12), but there was a minor statistical significant intragroup increase in 25(OH)D in both intervention arms (p < 0.001 for n-3 polyunsaturated fatty acids and p = 0.013 for corn oil, respectively). A positive correlation was noted between 25(OH)D and omega-3 prior to inclusion; r = 0.418, p = 0.007, attenuated at 12 months by purified omega-3 intervention; r = 0.021, p = 0.93. No positive correlation was observed between omega-6 and 25(OH)D.ConclusionLong-term treatment with a high dose of purified omega-3 as compared to corn oil did not improve serum concentrations of vitamin D.Clinical Trial Registration:ClinicalTrials.gov, Identifier: NCT01422317