Chien-Yuan Hou, Yung-Feng Lee and Yen-Hao Peng
Examination of steel moment resisting frames after the 1994 Northridge earthquake showed fatigue cracks presented in the beam–column connections of the frames. These observations…
Abstract
Purpose
Examination of steel moment resisting frames after the 1994 Northridge earthquake showed fatigue cracks presented in the beam–column connections of the frames. These observations indicate that fatigue failure may occur in the steel components of building structures in an earthquake event. To apply the fatigue design approach using the Palmgren–Miner’s rule for steel components of the moment resisting frames requires the knowledge regarding the damage index value at fatigue failure. The purpose of this paper is to perform fatigue tests to give the first damage values of steel components subjected to real earthquake-induced loadings.
Design/methodology/approach
The added-damping-and-stiffness steel plates which are used in building structures for earthquake mitigation were fabricated and tested by constant amplitude, SAC block and earthquake-induced loadings to failure. The earthquake loadings were obtained from the dynamic analysis of a steel frame with the mentioned plates. The load cycles of the SAC block and the calculated earthquake loadings were counted using the rainflow-counting method, and the damage index value of each specimen were calculated using the Palmgren–Miner’s rule.
Findings
Reverse stiffness obtained from cyclic load-displacement loops is a robust and consistent parameter that can be used for determining fatigue failure of tested components. The Palmgren–Miner’s damage values at failure, caused by earthquake loadings, are smaller than 1, and in addition, are also smaller than those obtained from the tests of the SAC block loading. The large-amplitude cycles in the earthquake loading produce large damage on the specimens, and intermediate range cycles also produce damage that should not be neglected in the fatigue analysis.
Originality/value
Today’s building design code allows large plastic deformation to occur in steel frames during an earthquake. However, the pre-Northridge earthquake steel frames showed fatigue cracks without the expected substantial plastic deformation at beam flanges. Proposed solutions to this problem were the reduced beam section neglecting the existence of the cracks at beam–column connections. This study considered the fatigue phenomenon in steel frames and provided the first set of tested fatigue damage values for steel components subjected to realistic earthquake loadings, which offered a possible method of dealing with fatigue cracks in the steel components of a building structure.
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Kobra Torfei Monfared, Marjan Vahedi, Roya Eshraghi Samani and Homayoon Moradnezhadi
The purpose of this research is to investigate factors influencing the intention of villagers to use renewable energy. In this regard, by using the modified model of planned…
Abstract
Purpose
The purpose of this research is to investigate factors influencing the intention of villagers to use renewable energy. In this regard, by using the modified model of planned behavior, perceived behavioral control factors, perceived usefulness, perceived ease, mental norm and attitude toward energy sources for the intention of villagers to use energy sources. Therefore, the impact of each of these five variables was investigated in the form of research hypotheses.
Design/methodology/approach
This research has been done using a quantitative paradigm and a descriptive-correlation method. The statistical population of the study consisted of households (384) living in rural areas of Ilam province. A multistage cluster method was used to select the sample size. The data collection tool was a researcher-made questionnaire that was developed based on the research background and research problem. Face validity of the research tool by professors of Islamic Azad University of Ilam and construct validity and reliability of research tools were confirmed by Cronbach’s alpha coefficient and composite reliability. Data were analyzed statistically using SPSS26 and SmartPLS3 software.
Findings
The results showed that the intention to use renewable energies (REs) among the rural peoples of Ilam province is affected by factors such as mental norms, attitude, perceived usefulness and perceived behavioral control and there is a positive and significant relationship between them.
Originality/value
In Iran, there is a lot of potential for usage of RE in rural communities, but compared to fossil fuels, had a small share in the current energy supply (Rezaei et al., 2022). RE technologies have not been sufficiently accepted and used by Iranian rural people (Rezaei and Ghafranfarid, 2018). Se the public acceptance of RE technologies is vital for successful process energy transfer (Huijts et al., 2012), non-acceptance of RE by society is a major obstacle to establishing RE technologies in Iran (Savari and Razmavar, 2022). It is expected that this research will fill the gap in the research literature.