• Structural Monitoring and Maintenance
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• v.2 no.3
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• pp.269-282
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• 2015

Civil structures should be designed with the lowest cost and longest lifetime possible and without service failure. The efficient and sustainable use of materials in building design and construction has always been at the forefront for civil engineers and environmentalists. Timber is one of the best contenders for these purposes particularly in terms of aesthetics; fire protection; strength-to-weight ratio; acoustic properties and seismic resistance. In recent years, timber has been used in commercial and taller buildings due to these significant advantages. It should be noted that, since the launch of the modern building standards and codes, a number of different structural systems have been developed to stabilise steel or concrete multistorey buildings, however, structural analysis of high-rise and multi-storey timber frame buildings subjected to lateral loads has not yet been fully understood. Additionally, timber degradation can occur as a result of biological decay of the elements and overloading that can result in structural damage. In such structures, the deficient members and joints require strengthening in order to satisfy new code requirements; determine acceptable level of safety; and avoid brittle failure following earthquake actions. This paper investigates performance assessment and damage assessment of older multi-storey timber buildings. One approach is to retrofit the beams in order to increase the ductility of the frame. Experimental studies indicate that Sprayed Fibre Reinforced Polymer (SFRP) repairing/retrofitting not only updates the integrity of the joint, but also increases its strength; stiffness; and ductility in such a way that the joint remains elastic. Non-linear finite element analysis ('pushover') is carried out to study the behaviour of the structure subjected to simulated gravity and lateral loads. A new global index is re-assessed for damage assessment of the plain and SFRP-retrofitted frames using capacity curves obtained from pushover analysis. This study shows that the proposed method is suitable for structural damage assessment of aged timber buildings. Also SFRP retrofitting can potentially improve the performance and load carrying capacity of the structure.

• Korean Journal of Agricultural Science
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• v.47 no.3
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• pp.577-596
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• 2020

Drought is a natural disaster that directly affects agriculture, which has a great impact on the global agricultural production system and yield. The lack of water storage in most parts of the country due to the lack of precipitation has caused a great increase in social interest in drought due to the dryness of rice fields and crops. As the drought period increases and the drought intensity becomes stronger, it is believed that drought damage to crops will continue; thus, it is necessary to understand the vulnerability to irrigation performance and the ability of irrigation facilities. Therefore, this study conducted a vulnerability assessment of irrigation facilities (public Groundwater well) in cities across the country. The survey was conducted using statistical data from 2007 to 2016, and the vulnerability score was calculated according to the vulnerability evaluation procedure for drought in the irrigation facilities (public groundwater wells). Among 157 regions, 136 areas were very vulnerable; 14 areas were vulnerable; 3 areas were normal; 4 areas were good, and 0 areas were excellent. The vulnerability assessment can be used as basic data for the development or maintenance of field irrigation facilities in the future by understanding the vulnerability of irrigation facilities.

• Earthquakes and Structures
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• v.18 no.6
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• pp.731-742
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• 2020

Due to incessant earthquakes, many historic South Nias traditional timber houses have been damaged while some still stand today. As Nias is part of an extremely active tectonic region and the buildings are getting older by day, it is essential that these unique houses are well maintained and functioning well. A post-earthquake condition assessment was conducted on 2 selected buildings; 'Building A' survived the seismic shakings while 'Building B' got severely damaged. The overall condition assessment of "Building A' was found out to be poor and the main structural members were not performing as intended. In 'Building B', the columns were not well anchored to the ground, no tie beams to tie the columns together, and eventually, the timber columns moved in various directions during the earthquake. The frequent earthquakes along with deterioration due to lack of proper maintenance program are responsible for the non-survival of the buildings. Thus, a process guideline for managing the maintenance of these buildings was proposed. This is necessary because managing the maintenance works could help to extend the life of the buildings and seek to avoid the need for potentially expensive and disruptive intervention works, which may damage the cultural significance of the buildings.

• Journal of Construction Engineering and Project Management
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• v.5 no.3
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• pp.18-28
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• 2015

Bidding and contract systems are used for public construction projects to select contractors following fair competition principles and to execute national budgets effectively. Many challenges have arisen due to a lack of transparency and fairness and because bidding practices have been luck-based. Few comprehensive or comparative analyses have been conducted on the performance and limitations of bidding and contract systems, and empirical analyses designed to improve policies on and the practice of such systems are lacking. This study empirically analyzed current bidding and contract systems to seek ways of improving them. The study proposes several alternatives to resolve the problems with and irrationalities of the current system: 1) improving bidding and selection systems by changing them from a luck-based price competition into a technical merit- and value-based competition; 2) improving the assessment criteria to meet the current market level of bid and winning prices; 3) adjusting contractual responsibilities and sharing structures to meet the current trend; and 4) strengthening the competitiveness and expanding the social responsibility-based procurement systems of construction companies.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.1
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• pp.1-8
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• 2014

The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction. The proposed reinforcement details have economic feasibility and rationality and make construction periods shorter. A model of hollow reinforced concrete bridge columns was tested under a constant axial load and a quasi-static cyclically reversed horizontal load. As a result, proposed reinforcement details for material quantity reduction were equal to existing reinforcement details in terms of required performance. The companion paper presents the experimental and analytical study for the performance assessment of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.3
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• pp.109-120
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• 2015

The purpose of this study was to investigate the performance of new hollow reinforced concrete (RC) bridge pier sections with triangular reinforcement details. The proposed triangular reinforcement details are economically feasible and rational and facilitate shorter construction periods. A model of pier sections with triangular reinforcement details was tested under quasi-static monotonic loading. As a result, proposed triangular reinforcement details was equal to existing reinforcement details in terms of required performance. In the companion paper, the parametric study for the performance assessment of new hollow RC bridge pier sections with triangular reinforcement details is performed.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.3
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• pp.107-115
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• 2013

The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction. The proposed reinforcement details has have economic feasibility and rationality and makes construction periods shorter. A model of column sections with reinforcement details for material quantity reduction was tested under quasistatic monotonic loading. As a result, the proposed reinforcement details for material quantity reduction was were equal to existing reinforcement details in terms of the required performance. In the a subsequent paper, the an experimental and analytical study will be performed for the performance assessment of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction will be performed.

• Earthquakes and Structures
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• v.15 no.6
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• pp.595-603
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• 2018

Shake table testing has been regarded as one of the most effective experimental approaches to evaluate seismic response of structural systems subjected to earthquakes. However, reproducing a prescribed acceleration time history precisely over the frequency of interest is challenging because shake table test systems are eventually nonlinear by nature. In addition, interaction between the table and specimen could affect the control accuracy of shake table testing significantly. Various novel control algorithms have been proposed to improve the control accuracy of shake table testing; however, reference values for control performance assessment remain rare. In this study, reference values for control performance assessment of shake table testing are specified based on the statistical analyses of 1,209 experimental data provided by the Seismic Simulator Laboratory of National Center for Research on Earthquake Engineering in Taiwan. Three individual reference values are considered for the assessment including the root-mean-square error of the achieved acceleration time history; the percentage of the spectral acceleration that exceeds the determined tolerance range over the frequency of interest; and the error-ratio of the achieved peak ground acceleration. Quartiles of the real experimental data in terms of the three objective variables are obtained, providing users with solid and simple references to evaluate the control performance of shake table testing. Finally, a set of experimental data of a newly developed control framework implementation for uni-axial shake tables are used as an application example to demonstrate the significant improvement of control accuracy according to the reference values provided in this study.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.182-183
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• 2006

It has been studied about the important consideration in designing and construction of the reliability assessment facilities including the combined testing system for simulating condition of acceleratedly deteriorated environment, which enable to test and evaluate the large-sized HV power apparatus without any disassembly up to transmission class in this paper. Also it is described simply about its ratings and main technical specifications and trial running of the system. To evaluate the performance characteristics against combined test condition for various power installation, especially for the polymer type insulators and kinds of bushings, brief investigation and an analysis of test objects and related international codes and standards have been conducted.

• Earthquakes and Structures
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• v.13 no.4
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• pp.365-375
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• 2017

Seismic risk management has two main technical aspects: to recommend the construction of high-performance buildings and other structures using earthquake-resistant designs or evaluate existing ones, and to prepare emergency plans using realistic seismic scenarios. An overview of seismic risk assessment methodologies in Croatia is provided with details regarding the components of the assessment procedures: hazard, vulnerability and exposure. For Croatia, hazard is presented with two maps and it is expressed in terms of the peak horizontal ground acceleration during an earthquake, with the return period of 95 or 475 years. A standard building typology catalogue for Croatia has not been prepared yet, but a database for the fourth largest city in Croatia is currently in its initial stage. Two methods for earthquake vulnerability assessment are applied and compared. The first is a relatively simple and fast analysis of potential seismic vulnerability proposed by Croatian researchers using damage index (DI) as a numerical value indicating the level of structural damage, while the second is the Macroseismic method.