Analysis of resistance to accelerated aging of the top layer of small-sized concrete elements. A case study

2020 ◽  
Vol 264 ◽  
pp. 120211
Author(s):  
Jerzy Bochen ◽  
Jan Ślusarek
Author(s):  
Sietse Witterholt ◽  
Roel Schipper ◽  
Steffen Grünewald ◽  
Pierre Hoogenboom ◽  
Rob Nijsse ◽  
...  

2020 ◽  
Vol 2020 (5) ◽  
pp. 60-1-60-8
Author(s):  
Oleksii Sidorov ◽  
Jon Y. Hardeberg ◽  
Sony George ◽  
Joshua S. Harvey ◽  
Hannah E. Smithson

This work takes a step towards understanding fundamental aspects of appearance change in cultural heritage. Particularly, we concentrate on the case study of the Hedal Madonna – a polychrome wood sculpture dated to the mid-1200s, and an important object of ecclesiastical art and Norwegian heritage. It is covered with a layered coating that gives rise to complex reflective properties and gives the sculpture a unique appearance. We studied the goniometric, spectral, and chromatic properties of mock-ups manufactured according to medieval techniques, and also carried out accelerated aging. We compared the properties of aged and original mock-ups, and found non-trivial changes in polychrome appearance. While the color of the mock-ups did not change significantly, we observed a noticeable change in their glossiness, presumably caused by structural degradation of the surface. We also found a difference in the goniometric properties of the polychrome material’s reflectance as a function of angle. Reflectance distributions that were originally symmetric with respect to angle became asymmetric. These findings will help to understand the original appearance of the Hedal Madonna, as well as aiding the design of appropriate conservation conditions for both the original statue and its recent reconstruction.


2016 ◽  
Vol 9 (6) ◽  
pp. 953-968
Author(s):  
D. Couto ◽  
◽  
P. Helene ◽  
L. C. Almeida ◽  
◽  
...  

ABSTRACT In recent years, the construction of foundation elements from large-volume reinforced concrete is becoming increasingly common. This implies a potential increase in the risk of cracks of thermal origin, due to the heat of hydration of cement. Under these circumstances, these concrete elements need to be treated using the mass concrete theory, widespread in dam construction, but little used when designing buildings. This paper aims to present a case study about the procedures and problems involved in the construction of a spread footing with a volume of approximately 800m³ designed for the foundation of a shopping center in São Paulo, Brazil.


2019 ◽  
Vol 284 ◽  
pp. 07001
Author(s):  
Grzegorz Adamczewski ◽  
Piotr Woyciechowski

The paper presents the case study of the degradation of architectural precast concrete elements on the facade of St. Michael the Archangel church in Warsaw. The background of the contemporary precast non-standard prefabrication was presented with the examples of polish recent applications. The GPR (ground penetrating radar) method was used in determining the location of reinforcement in the precast elements in the degraded façade. The conceptions of repair were analyzed and the reasons of the destructions of the precast elements.


2019 ◽  
Vol 270 ◽  
pp. 05006
Author(s):  
Yan Purnomo Safaa ◽  
Jati Utomo Dwi Hatmoko ◽  
Bambang Purwanggono

The increasing need for bridge infrastructure in Indonesia requires an efficient and lean construction process. The aim of this research to evaluate the use of precast concrete elements on bridges based on the Design for Manufacture and Assembly (DfMA) criteria. DfMA is a principle design that considers the process of manufacture and assembly components based on the following criteria, i.e., simplificity of design, number of components, standardization on elements or material and ease of handling. Analytical Hierarchy Process (AHP) is used to determine the weights for each criteria. Data were collected through observations on a bridge project, interviews with engineers and questionnaires. A typical girder and slab bridge is used as an object for DfMA-based evaluation. The results of evaluation design of prefabricated components to recommend some that are suitable for use in bridge construction. The last case study was taken to one of the bridge construction projects on the newly completed highway is done to identify the prefabricated components used. Bridge analysis and re-design are carried out with the DfMA concept, including costs incurred, resource scheduling and discussions of project risk. The results of analysis with simulation design giving efficiency 28,83% simplificity of design; 8,74% number of components and standardization on elements or materials; 25% ease of handling; 51,53% assembly time; 23,39% cost of work and 18,87% duration time. Finally, the level of risk of work received such as weather conditions and work safety is reduced. In closing, recommendations were given for further DfMA development.


Author(s):  
Tad-Song Kho ◽  
Florian Block ◽  
Thomas G. Lowry

As part of a refurbishment the height of a building in London is to be increased resulting in a change of the fire rating of the existing level from R60 to R90 as per prescriptive guidance. To investigate whether the inherent fire resistance of the structure would be sufficient a state-of-the-art probabilistic approach was adopted, with the approach extended to consider 2D heat-transfer to concrete elements. After determining the required reliability of the structure based on an acceptable risk level, a Monte-Carlo assessment was conducted. This considered for the proposed internal layouts and determined the range of input parameters to be randomly varied in order to define the required range of design fires analysed. The assessment demonstrated that the inherent structural fire resistance would provide sufficient structural reliability for the new use of the building and that no additional fire protection was required to the concrete frame.


2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
M. Sigit Darmawan ◽  
Ridho Bayuaji ◽  
N. A. Husin ◽  
R. B. Anugraha

This paper deals with the assessment of remaining service life of a cooling water intake concrete structure (CWICS) subjected to corrosion due to chloride attacks. Field and laboratory tests were performed to determine the current existing condition of the structure. Both destructive and nondestructive tests were employed to obtain the parameter needed for the assessment. Based on the current condition and test results, structural analysis was carried out and the remaining safety factor of CWICS was determined. From the analysis, it was found that most concrete elements of CWICS had safety factor greater than unity and might fulfil its intended service life up to the year 2033. However, fewer elements require immediate strengthening to extend their service life.


2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.


2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.


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