Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete

Many reinforced concrete bridges in Europe and around the world are damaged by reinforcement corrosion and the annual maintenance costs are enormous. It is therefore important to develop reliable methods to assess the structural capacity of corroded reinforced concrete structures and\ua0avoid unnecessary maintenance costs. Although there are advanced models for determining the load carrying capacity of structures, it is not obvious how they should be used to verify the performance of existing structures. To confidently assess the bond of corroded reinforcement in concrete, for example, the calculation model must give a sufficient safety margin. When designing new structures, semi-probabilistic approaches (such as the partial safety factor method) are adopted to achieve the target reliabilities specified in structural design codes. This paper uses probabilistic methods to develop partial factors for application in an existing bond model, to assess the safety of corroded reinforced concrete structures. The response of the bond model was\ua0studied using Monte Carlo (MC) simulations for several design cases, with probability distributions fitted to the results. Partial factors were then derived, based on these distributions. Furthermore, an MC-based simulation technique called “importance sampling” was used to study the reliability of several deterministic bond assessments conducted using these partial factors. The results show that deterministic assessments which use the proposed partial factors lead to a safety level at least equal to the target value. The results presented in this paper will support the assessment of reinforced concrete structures with anchorage problems and give a reasonable approximation of the anchorage capacity with sufficient safety margin. When generalised to\ua0cover other failure modes and structural configurations, this will enable better utilisation of damaged structures and lead to major environmental and economical savings for society

The effect of 5-aminolevulinic-acid (ALA) on the development of Saintpaulia ionantha

In recent work the effect of 5-aminolevulinic-acid (ALA) agent (commercial name Pentakeep-V) was examined on the chlorophyllcontent, growth and development of Saintpaulia ionantha. The newly re-rooted potted plants were irrigated or sprayed with 0.3‰ or 0.5‰Pentakeep-V solution, and plus 30% long lasting fertilizer was added to half of the all treatments. Control plants were sprayed with tap water.Best result were obtained on the field of flowering. All the treatments promoted chlorophyll-content in the leaves especially spraying with0.3‰concentration. Plants treated with Pentakeep-V in both concentrations and independently from the spraying or irrigation flowered morethan two weeks earlier than control and those that got plus 30% fertilizer. Besides in the case of some treatments the diameter of leaf rosette,the number and surface size of leaves grew comparing to the control. The longlasting fertilizer had positive effect on the fresh weight but noneof treatments had effect on the dry weight

The effect of 5-aminolevulinic-acid (ALA) on the development of Saintpaulia ionantha

In recent work the effect of 5-aminolevulinic-acid (ALA) agent (commercial name Pentakeep-V) was examined on the chlorophyll content, growth and development of Saintpaulia ionantha. The newly re-rooted potted plants were irrigated or sprayed with 0.3‰ or 0.5‰ Pentakeep-V solution, and plus 30% long lasting fertilizer was added to half of the all treatments. Control plants were sprayed with tap water. Best result were obtained on the field of flowering. All the treatments promoted chlorophyll-content in the leaves especially spraying with 0.3‰concentration. Plants treated with Pentakeep-V in both concentrations and independently from the spraying or irrigation flowered more than two weeks earlier than control and those that got plus 30% fertilizer. Besides in the case of some treatments the diameter of leaf rosette, the number and surface size of leaves grew comparing to the control. The longlasting fertilizer had positive effect on the fresh weight but none of treatments had effect on the dry weight

Structural characterisation of adaptive facades in Europe \u2013 Part I: Insight on classification rules, performance metrics and design methods

Adaptive facades are increasingly used in modern buildings, where they can take the form of complex systems and manifest their adaptivity in several ways. Adaptive envelopes must meet the requirements defined by structural considerations, which include structural safety, serviceability, durability, robustness and fire safety. For these novel skins, based on innovative design solutions, experimentation at the component and / or assembly level is required to prove that these requirements are fulfilled. The definition of appropriate metrics is hence also recommended. A more complex combination of material-related, kinematic, geometrical and mechanical aspects should in fact be properly taken into account, compared to traditional, static facades. Accordingly, specific experimental methods and regulations are required for these novel skins. As an outcome of the European COST Action TU1403 \u2018Adaptive facades network\u2019 - \u2018Structural\u2019 Task Group, this paper collects some recent examples and design concepts of adaptive systems, specifically including a new classification proposal and the definition of some possible metrics for their structural performance assessment. The aim is to provide a robust background and detailed state-of-the-art information for these novel structural systems, towards the development of standardised and reliable procedures for their mechanical and thermo-physical characterisation

Chromosome studies in Orchidaceae from Argentina

The center of diversity of Argentinean orchids is in the northeast region of the country. Chromosome numbers and karyotype features of 43 species belonging to 28 genera are presented here. Five chromosome records are the first ones at the genus level; these taxa are Aspidogyne kuckzinskii (2n = 42), Eurystyles actinosophila (2n = 56), Skeptrostachys paraguayensis (2n = 46), Stigmatosema polyaden (2n = 40) and Zygostates alleniana (2n = 54). In addition, a chromosome number is presented for the first time for 15 species: Corymborkis flava (2n = 56), Cyclopogon callophyllus (2n = 28), C. oliganthus (2n = 64), Cyrtopodium hatschbachii (2n = 46), C. palmifrons (2n = 46), Galeandra beyrichii (2n = 54), Habenaria bractescens (2n = 44), Oncidium edwallii (2n = 42), O. fimbriatum (2n = 56), O. pubes (2n = 84), O. riograndense (2n = 56), Pelexia ekmanii (2n = 46), P. lindmanii (2n = 46) and Warrea warreana (2n = 48). For Oncidium longicornu (2n = 42), O. divaricatum (2n = 56) and Sarcoglottis fasciculata (2n = 46+1B?, 46+3B?), a new cytotype was found. Chromosome data support phylogenetic relationships proposed by previous cytological, morphologic and molecular analyses, and in all the cases cover some gaps in the South American literature on orchid chromosomes

Microsoft Word - 5_WG3

Glass is inherently brittle and has a relatively low tensile strength. As a result the overarching design philosophy is to ensure adequate strength and stability for normal actions and to provide safe failure or adequate residual post-fracture capacity thereby minimising the risk of human injury. This fundamental 'fail-safe' concept is yet to be formally embedded in to the design process, largely due the lack of quantitative methods for assessing the post-fracture performance of glass. This shortcoming was the principal motivation for establishing Working Group 3 (WG3). It was recognised that the activities in this area required: 1. A deeper understanding of materials, component and system characteristics such as the effects of time / temperature / relative humidity on delamination; crack branching and fragmentation of glass, fail-safe connections etc. 2. A better understanding of the state-of-the-art approaches in mitigating failure in practice. This paper describes the work undertaken in this area by WG3. This is subdivided into work related to the core activities of WG3; work done in collaboration with other working groups: and participation in the other activities of this COST action such as short term scientific missions, development of the education pack and training school / workshops. CORE ACTIVITIES The first task undertaken by WG3 was to collate all relevant existing research in this area. This included the on-going research projects in this field of research. The latter is summarised in The second task was to identify the specific needs and expectation within this field and to establish which of these would be pursued further by WG3 and what methods would be adopted to do so Challenging Glass 4 & COST Actio

Special Issue on “Buildings and Structures under Extreme Loads II”

3siExceptional loads on buildings and structures are known to take origin and manifest from different causes, like natural hazards and possible high-strain dynamic effects, human-made attacks and impact issues for load-bearing components, possible accidents, and even unfavorable/extreme operational conditions. All these aspects can be critical for specific structural typologies and/or materials that are particularly sensitive to external conditions. In this regard, dedicated analysis methods and performance indicators are required for the design and maintenance under the expected lifetime. Typical issues and challenges can find huge efforts and clarification in research studies, which are able to address with experiments and/or numerical analyses the expected performance and capacity of a given structural system, with respect to demands. Accordingly, especially for existing structures or strategic buildings, the need for retrofit or mitigation of adverse effects suggests the definition of optimal and safe use of innovative materials, techniques, and procedures. This Special Issue follows the first successful edition [1] and confirms the need of continuous research efforts in support of building design under extreme loads, with 13 original research papers focused on various key aspects of structural performance assessment for buildings and systems under exceptional design actions and operational conditions.openopenBedon, Chiara; Stochino, Flavio; Honfi, DanielBedon, Chiara; Stochino, Flavio; Honfi, Danie

Human actors, a system vulnerability or a capability for adaptation to enhance resilience of transport networks?

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Integral Design and Managemen