scholarly journals Time-Dependent Analysis of Precast Segmental Bridges

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Gian Felice Giaccu ◽  
Davide Solinas ◽  
Bruno Briseghella ◽  
Luigi Fenu
Keyword(s):  
Time Dependent ◽  
Long Term Effects ◽  
Model Code ◽  
Dependent Behavior ◽  
Model Code 2010 ◽  
Fiber Reinforcements ◽  
Segmental Bridges ◽  
Term Creep ◽  
Over Time

AbstractPrestressed segmentally constructed balanced cantilever bridges are often subjected to larger deflections than those predicted by calculations, especially for long-term effects. In this paper, the case of modular balanced cantilever bridges, which are prestressed segmental bridges obtained through a repetition of the same double cantilever, is investigated. The considered bridges are two typical cases of modular balanced cantilever both subjected to large deformations during their lifetime. In this case, due to the unusual employed static scheme, creep deflections indefinitely evolve over time particularly at the end of the cantilevers and in correspondence with the central joint. These remarkable deflections cause discomfort for vehicular traffic and in certain cases can lead to the bridge collapse. Important extraordinary maintenance interventions were necessary to restore the viability of the bridges and to replace the viaduct design configuration. To this aim, the static schemes of the structures were varied, introducing new constraints, new tendons, and carbon fiber reinforcements. In the present work, time analysis was performed to compare the time-dependent behavior of the bridge according to two different creep models, the CEB-FIP Model Code 2010 and the RILEM Model B3, with the real-time-dependent behavior of the bridge observed during its lifetime. The two different employed models exhibit different behaviors in terms of displacements and bending moments acting on the bridge. Interesting considerations are made on their reliability in simulating the long-term creep effects that evolve indefinitely over time. Moreover, retrofitting techniques have been proposed and modeled to predict their effectiveness in reducing time-dependent deflections.

scholarly journals Long-Term Concrete Shrinkage Influence on the Performance of Reinforced Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 254
Author(s):  
Alinda Dey ◽  
Akshay Vijay Vastrad ◽  
Mattia Francesco Bado ◽  
Aleksandr Sokolov ◽  
Gintaris Kaklauskas
Keyword(s):  
Reinforced Concrete ◽  
Reinforced Concrete Structures ◽  
Tension Stiffening ◽  
Model Code ◽  
Concrete Shrinkage ◽  
Time Period ◽  
Governing Factor ◽  
Model Code 2010 ◽  
Mathematical Process

The contribution of concrete to the tensile stiffness (tension stiffening) of a reinforced concrete (RC) member is a key governing factor for structural serviceability analyses. However, among the current tension stiffening models, few consider the effect brought forth by concrete shrinkage, and none studies take account of the effect for very long-term shrinkage. The present work intends to tackle this exact issue by testing multiple RC tensile elements (with different bar diameters and reinforcement ratios) after a five-year shrinking time period. The experimental deformative and tension stiffening responses were subjected to a mathematical process of shrinkage removal aimed at assessing its effect on the former. The results showed shrinkage distinctly lowered the cracking load of the RC members and caused an apparent tension stiffening reduction. Furthermore, both of these effects were exacerbated in the members with higher reinforcement ratios. The experimental and shrinkage-free behaviors of the RC elements were finally compared to the values predicted by the CEB-fib Model Code 2010 and the Euro Code 2. Interestingly, as a consequence of the long-term shrinkage, the codes expressed a smaller relative error when compared to the shrinkage-free curves versus the experimental ones.

Long-term effects of preplant liming on apple trees and soil cation levels

1991 ◽  
Vol 71 (4) ◽  
pp. 545-549
Author(s):  
G. H. Neilsen ◽  
E. J. Hogue ◽  
P. B. Hoyt
Keyword(s):  
Calcium Hydroxide ◽  
Apple Tree ◽  
Sandy Loam ◽  
Long Term Effects ◽  
Apple Trees ◽  
Orchard Soil ◽  
Lime Application ◽  
Over Time ◽  
Key Words Apple

Nine years after liming a sandy loam orchard soil to pH 6.0 with calcium hydroxide or dolomitic lime, pH and extractable Ca and Mg were still higher where limed than where unlimed. However, pH had decreased below 5.0 in the limed and N-fertilized plots. Delicious (Malus domestica Borkh.) apple tree nutrition benefited from the two soil amendments. Leaf Mg was increased by dolomite. Leaf Ca was increased by calcium hydroxide. Leaf Mn, although highest in unlimed soils, increased over time for both limed and unlimed soil. Key words: Apple, lime application, reacidification

scholarly journals The Long-term Effects of Instruction on EFL Learners' Use of Complaining Formulas

10.29007/5xsb ◽  
2018 ◽  
Author(s):  
Alicia Martínez-Flor ◽  
Esther Usó-Juan
Keyword(s):  
Foreign Language ◽  
Language Learners ◽  
Future Research ◽  
Long Term Effects ◽  
Positive Role ◽  
Efl Learners ◽  
Foreign Language Learners ◽  
Over Time

Studies analysing the positive role of pragmatic instruction in formal settings have increased over the last decades. Within this area of interventional pragmatics, some studies have particularly examined whether the effectiveness of the instruction implemented is sustained over time. In order to shed more light on the long-term effects of instruction, this research investigates English as a Foreign Language learners’ use of complaining formulas not only after immediately receiving instruction, but also two months later. Results show that learners keep using a variety of appropriate complaining formulas two months after having participated in the instructional period. These findings are discussed and directions for future research suggested.

China's Economic Growth and Innovation in Globalization

2019 ◽  
pp. 1-27
Author(s):  
Bryan Christiansen
Keyword(s):  
Economic Integration ◽  
Capital Flows ◽  
Direct Investment ◽  
Chinese Economy ◽  
Business Organizations ◽  
Long Term Effects ◽  
Critical Determinant ◽  
National Economies ◽  
Over Time

The purpose of this chapter is to investigate the potential long-term effects of contemporary globalization on the Chinese economy and innovation in an era of global hypercompetition. Globalization today is basically accepted as the process that removes geographical boundaries and enables the economic integration and interdependence of national economies into the international economy through trade, foreign direct investment, migration, and capital flows. Since productivity remains the critical determinant of long-term national growth and prosperity, the effects of today's globalism on productivity demands the need for business organizations in particular to sustain a competitive advantage and to remain profitable over time. Based on an integrative literature review, this chapter explores why China must continue to develop its innovation capabilities as well as to provide opportunities for foreign businesses over the long-term via responsible economic development that also benefits the nation's domestic population.

The Final Score

2020 ◽  
pp. 201-210
Author(s):  
Steven M. Ortiz
Keyword(s):  
Lived Experience ◽  
Longitudinal Research ◽  
Long Term Effects ◽  
Professional Athlete ◽  
The Past ◽  
Personal Empowerment ◽  
Final Score ◽  
Short And Long Term ◽  
Over Time

The conclusion provides some final observations about the longitudinal research itself and its short- and long-term effects on the women involved. It briefly touches on the few areas of the sport marriage that have seen improvement in the past few decades, discusses the conscious decisions the women make to continue normalizing the career-dominated marriage, and reports on how the marriages fared over time. It also describes the women’s personal empowerment as a result of their participation in the research. Finally, it summarizes the advice and suggested keys to a successful sport marriage that the wives in both studies offered, based on their lived experience. This overview essentially describes how and why the wife of a male professional athlete must adapt to realities if she wants her marriage to survive her husband’s career and retirement.

Delayed arteriolar relaxation after prolonged agonist exposure: functional remodeling involving tyrosine phosphorylation

2003 ◽  
Vol 285 (2) ◽  
pp. H849-H856 ◽  
Author(s):  
Michael A. Hill ◽  
Simon J. Potocnik ◽  
Luis A. Martinez-Lemus ◽  
Gerald A. Meininger
Keyword(s):  
Tyrosine Phosphorylation ◽  
Prolonged Exposure ◽  
Time Dependent ◽  
Physiological Salt Solution ◽  
Microtubule Network ◽  
Biochemical Alterations ◽  
Dependent Behavior ◽  
Functional Remodeling ◽  
Short And Long Term

Although arteriolar contraction is dependent on Ca2+-induced myosin phosphorylation, other mechanisms including Ca2+ sensitization and time-dependent phenomena such as cytoskeletal and cellular reorganization may contribute to contractile events. We hypothesized that if arteriolar smooth muscle exhibits time-dependent behavior this may be manifested in differences in relaxation after short- and long-term exposure to contractile agonists. Studies were conducted in isolated arterioles pressurized to 70 mmHg. In initial experiments ( n = 10), rate of relaxation was measured after acute (5 min) or prolonged (4 h) exposure to 5 μM norepinephrine (NE). Prolonged exposure to NE resulted in significantly ( P < 0.05) increased time for relaxation in physiological salt solution. Rapid relaxation of vessels exposed to NE for 4 h was observed after superfusion with 0 mM Ca2+ buffer, indicating that the alteration in relaxation was reversible and Ca2+ dependent. A similarly impaired dilation was not observed with 4-h exposure to KCl (75 mM). To determine mechanisms contributing to the effects of prolonged NE exposure, studies were performed in the presence of the microtubule depolymerizing agent demecolcine (10 μM) or a series of tyrosine phosphorylation inhibitors. Although demecolcine caused significant vasoconstriction ( P < 0.05) and potentiated NE vasoconstriction, it did not prevent the effect of long-term NE exposure on relaxation. Genistein, although having no effect on acute NE-induced contraction, concentration-dependently inhibited prolonged NE constriction. Similarly, Src (PP1) and p42/44 MAP kinase (PD-98059) inhibitors prevented maintenance of long-term NE contraction. The data indicate that prolonged exposure to NE induces biochemical alterations that impair relaxation after removal of the agonist. The contractile effects are Ca2+ dependent and involve tyrosine phosphorylation but do not appear to involve the polymerization state of the microtubule network.

Creep–rupture model of aluminum alloys: Cohesive zone approach

2014 ◽  
Vol 229 (8) ◽  
pp. 1343-1347 ◽  
Author(s):  
Kyungmok Kim
Keyword(s):  
Aluminum Alloys ◽  
Cohesive Zone ◽  
Rupture Life ◽  
Stress Rupture ◽  
Creep Rupture ◽  
Time Dependent ◽  
Element Analysis ◽  
Rupture Model ◽  
Term Creep

In this article, a creep–rupture model of aluminum alloys is developed using a time-dependent cohesive zone law. For long-term creep rupture, a time jump strategy is used in a cohesive zone law. Stress–rupture scatter of aluminum alloy 4032-T6 is fitted with a power law form. Then, change in the slope of a stress-rupture line is identified on a log–log scale. Implicit finite element analysis is employed with a model containing a cohesive zone. Stress–rupture curves at various given temperatures are calculated and compared with experimental ones. Results show that a proposed method allows predicting creep–rupture life of aluminum alloys.

scholarly journals Progression of mild cognitive impairment to dementia: a challenge to current thinking

2006 ◽  
Vol 189 (5) ◽  
pp. 399-404 ◽  
Author(s):  
Anja Busse ◽  
Matthias C. Angermeyer ◽  
Steffi G. Riedel-Heller
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Community Sample ◽  
Neuropsychological Testing ◽  
Time Dependent ◽  
Current Thinking ◽  
Conversion Rates ◽  
Over Time ◽  
Long Term Studies

BackgroundStudies of conversion from mild cognitive impairment to dementia suggest a linear progression over time. Conversion rates during lifetime may extend to 80–90%.AimsThis study examines the time-dependent evolution from mild cognitive impairment to dementia. Current assumptions regarding yearly and lifetime conversion rates are challenged.MethodA community sample of 1045 dementia-free individuals aged 75 years and over was examined by neuropsychological testing based on 6 years of observation.ResultsApproximately 60–65% of people with mild cognitive impairment develop clinical dementia during their life. Progression from mild cognitive impairment to dementia appears to be time dependent, occurring primarily within the initial 18 months.ConclusionsFurther long-term studies are needed to examine the time-dependent evolution from mild cognitive impairment to dementia and to establish age-specific conversion rates during lifetime.

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