Renato Silva Nicoletti, Tawan Oliveira, Alex Sander Clemente de Souza and Silvana De Nardin
In the analysis of structures in a fire situation by simplified and analytical methods, one assumption is that the fire resistance time is greater than or equal to the required…
Abstract
Purpose
In the analysis of structures in a fire situation by simplified and analytical methods, one assumption is that the fire resistance time is greater than or equal to the required fire resistance time. Among the methodologies involving the fire resistance time, the most used is the tabular method, which associates fire resistance time values to structural elements based on minimum dimensions of the cross section. The tabular method is widely accepted by the technical-scientific community due to the fact that it is safe and practical. However, its main criticism is that it results in lower fire resistance times than advanced thermal and thermostructural analysis methods. The objective of this study was to evaluate the fire resistance time of reinforced concrete beams and compare it with the required fire resistance time recommended by the tabular method of NBR 15200 (ABNT, 2012).
Design/methodology/approach
The fire resistance time and required fire resistance time of reinforced concrete beams were evaluated using, respectively, numerical models developed based on the finite element method and the tabular method of NBR 15200 (ABNT, 2012). The influence of the following parameters was investigated: longitudinal reinforcement cover, characteristic compressive strength of concrete, beam height, longitudinal reinforcement area and arrangement of steel bars.
Findings
Among the evaluated parameters, the covering of the longitudinal reinforcement proved to be more relevant for the fire resistance time, justifying that the tabular method of NBR 15200 (ABNT, 2012) being strongly and directly influenced by this parameter. In turn, more resistant concretes, higher beams and higher steel grades have lower fire resistance time values. This is because beams in these conditions have greater resistance capacity at room temperature and, consequently, are subject to external stresses of greater magnitude. In some cases, the fire resistance time was even lower than the required fire resistance time prescribed by NBR 15200 (ABNT, 2012). Both the fire resistance time and the required fire resistance time were not influenced by the arrangement of the longitudinal reinforcements.
Originality/value
The present paper innovates by demonstrating the influence of other important design variables on the required fire resistance time of the NBR 15200 (ABNT, 2012). Among several conclusions, it was found that the load level to which the structural elements are subjected considerably affects their fire resistance time. For this reason, it was recommended that the methods for calculating the required fire resistance time consider the load level. In addition, the article quantifies the security degree of the tabular method and exposes some situations for which the tabular method proved to be unsafe. Moreover, in all the models analyzed, the relationship between the span and the vertical deflection associated with the failure of the beams in a fire situation was determined. With this, a span over average deflection relationship was presented in which beams in fire situations fail.
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Mauro Vivaldini and Paulo Renato de Sousa
The paper aims to further understanding of connectivity from the perspective of blockchain technology (BT) in the supply chain (SC). It presents the weaknesses (inhibitors) of…
Abstract
Purpose
The paper aims to further understanding of connectivity from the perspective of blockchain technology (BT) in the supply chain (SC). It presents the weaknesses (inhibitors) of connectivity during technology implementation, focusing on supply chain interaction and resilience.
Design/methodology/approach
Restricting the focus to digital connectivity, interaction and supply chain resilience, this paper uses a systematic literature review (SLR) to examine how the literature has addressed, related or flagged connectivity weaknesses affecting supply chain interaction and resilience.
Findings
This study highlights the influence of connectivity for blockchain-technology projects. Technical and organisational influencers that affect the adoption of technology in the SC are presented. These influencers support the factors proposed in this study regarding the weaknesses that negatively affect the interaction between the agents involved and the SC's resilience. The research suggests that the weaknesses are related to technical needs and the relationships between companies arising from functionalities.
Research limitations/implications
This paper is restricted to a review of the theory and the researched material. Although the author was careful to choose the best search terms related to the research objective, some potentially relevant articles may have been excluded.
Practical implications
The study summarises research on blockchain connectivity influencers in the SC, helping managers to anticipate and mitigate some of doubts and concerns in projects of this nature.
Originality/value
This is one of the first articles in the area of operations and SCs that addresses the topic of connectivity, focusing on its restrictive factors (connectivity inhibitors), in the context of blockchain implementation in the SC.