Features of the development of international standards of subcommittee No.5 of ISO/TC71 «Simplified design standard for concrete structures»

2020 ◽  
pp. 5-12
Author(s):  
Peter Arleninov ◽  
Keyword(s):  
Concrete Structures ◽  
International Standards ◽  
Design Standard

Service Life of Concrete Structures

2020 ◽  
Vol 309 ◽  
pp. 267-271
Author(s):  
Milan Holicky ◽  
Jiří Kolísko
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Limit State ◽  
Concrete Structures ◽  
Technical Specification ◽  
Working Life ◽  
Degradation Process ◽  
International Standards ◽  
Limit States ◽  
Existing Structures

The concept of service life of structures is included in international standards ISO (under the term Design Working Life), in the European document EN 1990 (Design Service Life) and in the upcoming document CEN for assessment of existing structures - Technical Specification TS (Remaining Working Life). The mentioned documents contain mainly material-independent provisions for the design and assessment of all types of structures and for any category of actions. The submitted paper includes the definition of service life (performance time) tser, which is extended for any concrete structure, considering the resistance of a structure R(t) and the effect of action S(t). Both the aggregate variables R(t) and S(t) are usually random variables significantly dependent on time t. Due to the random variability of the variables R(t) and S(t), the service life tser, needs to be related to the probability that the performance of the structure is weakened or completely eliminated. Basically, serviceability limit states (SLS) and ultimate limit states (ULS) should be considered. In the case of concrete structures another limit state corresponding to the beginning of a specific degradation process (corrosion of reinforcement), denoted tinit, may be important. In specific cases of buildings and bridges a functional (moral) service life may be taken into account. The paper includes also a practical example of assessing the remaining working life of a concrete structure.

International Civil Ageing Management and Assessment Methodology of Concrete

2019 ◽  
Author(s):  
F. H. E. de Haan – de Wilde ◽  
C. G. M. de Bont
Keyword(s):  
Degradation Mechanism ◽  
Concrete Structures ◽  
Assessment Method ◽  
International Experience ◽  
International Standards ◽  
Assessment Methodology ◽  
Civil Structures ◽  
Starting Point ◽  
Operation Period ◽  
Ageing Management

Abstract For many nuclear power plants worldwide the operation period will be extended to 60 or 80 years in the coming years. As the operation period increases, the importance of knowledge of ageing mechanisms increases. In the framework of LTO there is limited knowledge about ageing and structural integrity of concrete structures. Knowledge about the strength of concrete structures and modelling thereof can be improved for a more complete knowledge base on ageing and degradation mechanism in nuclear facilities. Therefore, effort is required to improve the knowledge of concrete, material models and finite element modelling techniques as well as the assessment method. Recent developments have shown that ageing of civil structures receive more attention internationally (E.g. concrete degradation in bunker building Doel). Traditionally a large part of the research and development is focused on mechanical issues like piping and vessels. In order to increase the knowledge in the field of civil structures, the focus is on investigation of ageing of concrete and determining analysis methods. This paper focuses on the development of a practical assessment method for ageing of civil structures. As a first step information from international publications and other sources on civil structures ageing issues and management thereof, will be gathered. Well known international standards taking care of ageing phenomena based on problem areas and good practices are IGALL and GALL. IGALL and GALL contain information tables based on international experience. This is the starting point of the research in finding an assessment methodology for civil ageing management. It will be shown that IGALL and GALL contain very similar elements. Sorting on the AMPs results in a practical set of datasheets with summarizing information per AMP, including the underlying international experience. The datasheets are of limited size, presenting an helpful overview of the relevant structures or components, materials, environment and mechanisms. A method for civil ageing management is proposed which will be applied and developed in more detail in future research. Further research is necessary to develop a specific assessment methodology for concrete.

scholarly journals Elaboración de hormigones que minimicen el impacto al ambiente, empleando neumáticos usados de vehículos livianos y pesados, en la provincia de Santa Elena.

2015 ◽  
Vol 2 (3) ◽  
Author(s):  
Armando Saltos ◽  
Humberto Guerrero ◽  
Linda Ordóñe ◽  
Miguel Suárez
Keyword(s):  
Environmental Impact ◽  
Selection Process ◽  
Concrete Structures ◽  
American Concrete Institute ◽  
International Standards ◽  
Investment Promotion ◽  
Santa Elena ◽  
Low Traffic

Las llantas de desecho son consideradas un foco de riesgo ambiental y sanitario a nivel mundial, por ejemplo en Ecuador se desecha al año, según la Corporación para la Promoción Proactiva de Inversiones ( INVEC), cerca de 2,4 millones de neumáticos de diversos tipos, lo que equivale a 55.000 toneladas. Un menor porcentaje de ellos son reutilizados para el reencauchado, pero la gran mayoría es incinerada o depositada en basureros a cielo abierto, lo que supone una  amenaza contra el medio ambiente y riesgos a la salud. El proyecto busca la creación de un diseño de hormigón con partículas  provenientes de neumáticos usados, que después de un proceso de selección de los neumáticos a usar, de una trituración controlada y una dosificación acorde con los parámetros de las normas internacionales de diseño de hormigón del Instituto Americano del Concreto (ACI) y de la Norma Ecuatoriana de la Construcción  (NEC), se obtenga un hormigón de resistencias aceptables que puedan ser empleadas en: calles de bajo tránsito, banquetas y zonas peatonales y otras estructuras de hormigón,  minimizando así el impacto ambiental que se produce por el mal manejo de llantas usadas en la provincia de Santa Elena.AbstractWaste from rubbers tires are considered to be an environmental and sanitary risk worldwide. As an example in Ecuador, every year nearly 2.4 million rubber tires of various types are discarded as trash, which is equivalent to 55000 tons, according to the Proactive Corporation for Investment Promotion (INVEC). A small porcentage of the waste, are reused to be re-rubberized. But the majority is incinerate or deposited in dumping grounds open to the environment, which is a huge risk to the environment and the health of individuals. The project seeks to create a design of concrete including particles of rubber from discarded tires. The tires will undergo a rigorous selection process, a controlled threading process, and a fabrication according to the specifications of the international standards of concrete of the American Concrete Institute (ACI) and the Construction Ecuatorian Standards (NEC), and based on these specifications, the goal is to obtain an acceptable concrete apt to be used in low traffic streets, sidewalks, pedestrian zones, and other concrete structures, minimizing the environmental impact to the misuse of tires in the province of Santa Elena.

scholarly journals Performance evaluation of plastic spacers: proposal and development of evaluation methods

2016 ◽  
Vol 9 (6) ◽  
pp. 911-952
Author(s):  
M. F. F. Menna Barreto ◽  
◽  
A. P. Maran ◽  
D. C. C. Dal Molin ◽  
J. R. Masuero
Keyword(s):  
Performance Evaluation ◽  
Reinforced Concrete ◽  
Concrete Structures ◽  
Concrete Cover ◽  
International Standards ◽  
Performance Criteria ◽  
Reinforced Concrete Structures ◽  
And Performance ◽  
Cover Thickness ◽  
Brazilian Standard

ABSTRACT The durability of reinforced concrete structures is highly dependent on the characteristics of the concrete cover to reinforcement and its thickness. The failure to obtain cover thickness is the factor with the largest influence on the premature corrosion of the reinforcement, which in turn is the main deterioration form of reinforced concrete structures. Studies indicate that the designed cover is not reached in the current constructions that adopt this structural solution, configuring a chronic, and not a sporadic problem. One of the observed causes for the failure in obtaining the minimum standardized cover is the incorrect use of spacers and the use of inadequate spacers. This is made more serious by the absence of a Brazilian standard to regulate the product and its use and, consequently, the absence of a quality certification from the responsible regulating agency. Focusing on spacers, requirements and performance criteria were proposed, in addition to methods for their assessment, with most being taken and adapted from international standards. Subsequently, some spacers available on the market were effectively tested according to the proposed methodology. No spacer model proved to be satisfactory according to the established performance approach. However, for each criteria and assessment methods proposed, there was, at least, one spacer model at the market which satisfied them, so it can be said that the criteria and methods are suitable for spacers performance evaluation. Faced with the performance diversity of the spacer models on offer, the need for a regulatory Brazilian standard for this product was confirmed in order to delimit the quality of spacers available on the market and to eliminate this variable as one of the causes for not obtaining the correct covering.

scholarly journals Determination of Modelling Error Statistics for Cold-Formed Steel Columns

2020 ◽  
Vol 2020 ◽  
pp. 1-25 ◽  
Author(s):  
R. P. Rokade ◽  
K. Balaji Rao ◽  
B. Palani
Keyword(s):  
Failure Modes ◽  
International Standards ◽  
Research Centre ◽  
Distortional Buckling ◽  
Design Standards ◽  
Buckling Mode ◽  
Design Standard ◽  
Cold Formed Steel ◽  
Test Database ◽  
Modelling Error

In this article, an attempt has been made to estimate the Modelling Error (ME) associated with compression capacity models available in international standards for different failure modes of compression members fabricated from Cold-Formed Steel (CFS) lipped channel sections. For the first time, a database has been created using test results available in the literature for compression capacities of CFS lipped-channel sections. The database contains details of 273 numbers of compression member tests which have failed in different failure modes, namely, (i) flexural, torsional, flexural-torsional, local, and distortion buckling and (ii) failure by yielding. Only those sources, which report all the details, required to compute the capacities using different standards are included in the database. The results of experimental investigations carried out at CSIR-Structural Engineering Research Centre, Chennai, are also included in this test database. The international codes of practice used in calculation of compression capacities of the database columns considered in this paper are ASCE 10-15 (2015), AISI S100-16 (2016), AS/NZS 4600: 2018 (2018), and EN 1993-1-3:2006 (2006). The ASCE, AISI, AS/NZS, and EN design standards have different design guidelines with respect to the failure modes, e.g., ASCE 10-15 (2015) standard provides stringent criteria for maximum width to thickness ratio for stiffened and unstiffened elements. Hence, guidelines for the distortional buckling mode are not provided, whereas the AISI S100-16 (2016) and AS/NZS 4600: 2018 (2018) standards consider separate guidelines for distortional buckling mode and EN 1993-1-3:2006 (2006) standard considers combined local and distortional buckling mode. Further, the sample size for each design standard is varying depending on the design criteria and failure mode. Studies on statistical analysis of ME suggest that the compression capacity predicting models for flexural-torsional buckling mode are associated with large variation irrespective of the design standard. Similar observations are made for the flexural buckling model as per EN 1993-1-3:2006 (2018) standard and distortional buckling models as per AISI S100-16 (2016) and AS/NZS 4600: 2018 (2018) standards. The compression capacities for test database sections are evaluated by neglecting the partial safety factors available in design standards. The probabilistic analysis to determine statistical characteristics of compression capacity indicates the importance of consideration of ME as a random variable. Hence, the ME results will be useful in code calibration studies and may have potential reference to design practice.

Adult’s Total Parenteral Nutrition: Initiative and Implementation of Standardized Formulation in Saudi Arabia

2018 ◽  
Vol 4 (3) ◽  
pp. 483-487
Author(s):  
Yousef Ahmed Alomi ◽  
Hussam Saad Almalki ◽  
Aisha Omar Fallatah ◽  
Awatif Faraj Alshammari ◽  
Nahedh Rashed Alotaibi
Keyword(s):  
Saudi Arabia ◽  
Parenteral Nutrition ◽  
Pharmacy Practice ◽  
International Standards ◽  
Kingdom Of Saudi Arabia ◽  
Parental Nutrition ◽  
International Regulations ◽  
One Year ◽  
New Formulation ◽  
New System

The general administration of pharmaceutical care started potential pharmacy practice program. The program is part of accreditation professional’s process of national and international regulations. The adult’s parenteral nutrition was one of the critical programs. The most healthcare professionals are not familiar with the new system. The new initiatives system adult’s standardized concentration formulation of total parental nutrition as complementary to the previous one. The new formulation consisted of all parental nutrition requirements based on national and international standards. The new system can be converted as computerized physician orders. The new initiatives may implement as project management model over one year or less than that’s. The new system prevents nutrition-related problems, and medication errors, and improve clinical outcomes of the adults’ population in the Kingdom of Saudi Arabia.

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