• International Journal of High-Rise Buildings
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• v.3 no.4
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• pp.285-296
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• 2014

The objective of optimization is to present a design process that minimizes the total material consumption while satisfying current codes and specifications. In the research an optimization formulation for RC shear wall structures is proposed. And based on conceptual design methodology, an optimization process is investigated. Then optimal design techniques and specific explanations are introduced for residential buildings with shear wall structure, especially for that with a rectangular layout. An example of 30-story building is presented to illustrate the effectiveness of the proposed optimal design process. Furthermore, the influence of aspect ratio on the concrete consumption and the steel consumption of the superstructure are analyzed for this typical RC shear wall structure; and their relations are obtained by regressive analysis. Finally, the optimal material consumption is suggested for the residential building with RC shear wall structure and with rectangular layout. The relation and the data suggested can be used for guiding the design of similar RC shear wall structures.

• Earthquakes and Structures
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• v.11 no.3
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• pp.483-503
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• 2016

This study aims to evaluate seismic performance of existing low and mid-rise reinforced concrete buildings by comparing their displacement capacities and displacement demands under selected ground motions experienced in Turkey as well as demand spectrum provided in 2007 Turkish Earthquake Code for design earthquake with 10% probability of exceedance in 50 years for soil class Z3. It should be noted that typical residential buildings are designed according to demand spectrum of 10% probability of exceedance in 50 years. Three RC building sets as 2-, 4- and 7-story, are selected to represent reference low-and mid-rise buildings located in the high seismicity region of Turkey. The selected buildings are typical beam-column RC frame buildings with no shear walls. The outcomes of detailed field and archive investigation including approximately 500 real residential RC buildings established building models to reflect existing building stock. Total of 72 3-D building models are constructed from the reference buildings to include the effects of some properties such as structural irregularities, concrete strength, seismic codes, structural deficiencies, transverse reinforcement detailing, and number of story on seismic performance of low and mid-rise RC buildings. Capacity curves of building sets are obtained by nonlinear static analyses conducted in two principal directions, resulting in 144 models. The inelastic dynamic characteristics are represented by "equivalent" Single-Degree-of- Freedom (ESDOF) systems using obtained capacity curves of buildings. Nonlinear time history analysis is used to estimate displacement demands of representative building models idealized with (ESDOF) systems subjected to the selected ground motion records from past earthquakes in Turkey. The results show that the significant number of pre-modern code 4- and 7-story buildings exceeds LS performance level while the modern code 4- and 7-story buildings have better performances. The findings obviously indicate the existence of destructive earthquakes especially for 4- and 7-story buildings. Significant improvements in the performance of the buildings per modern code are also obvious in the study. Almost one third of pre-modern code buildings is exceeding LS level during records in the past earthquakes. This observation also supports the building damages experienced in the past earthquake events in Turkey.

• Earthquakes and Structures
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• v.9 no.5
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• pp.1069-1089
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• 2015

This paper investigates the limits and efficacies of the Fiber Reinforced Polymer (FRP) material for strengthening mid-rise RC buildings against seismic actions. Turkey, the region of the highest seismic risk in Europe, is chosen as the case-study country, the building stock of which consists in its vast majority of mid-rise RC residential and/or commercial buildings. Strengthening with traditional methods is usually applied in most projects, as ordinary construction materials and no specialized workmanship are required. However, in cases of tight time constraints, architectural limitations, durability issues or higher demand for ductile performance, FRP material is often opted for since the most recent Turkish Earthquake Code allows engineers to employ this advanced-technology product to overcome issues of inadequate ductility or shear capacity of existing RC buildings. The paper compares strengthening of a characteristically typical mid-rise Turkish RC building by two methods, i.e., traditional column jacketing and FRP strengthening, evaluating their effectiveness with respect to the requirements of the Turkish Earthquake Code. The effect of FRP confinement is explicitly taken into account in the numerical model, unlike the common procedure followed according to which the demand on un-strengthened members is established and then mere section analyses are employed to meet the additional demands.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.3
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• pp.103-111
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• 2018

This study examines the seismic failure of RC low-rise building structures having irregularities at the ground story during the 15 November 2017 Pohang, Korea, earthquake, $M_w=5.4$, which is the second strongest since the government began monitoring them in 1978 in South Korea. Some 2,000 private houses were damaged or destroyed in this earthquake. Particularly, serious damage to the piloti story of RC low-rise residential building structures of fewer than five stories was observed within 3 km of the epicenter with brittle shear failure of columns and walls due to severe torsional behavior. Buildings below six stories constructed before 2005 did not have to comply with seismic design requirements, so confinement detailing of columns and walls also led to inadequate performance. However, some buildings constructed after 2005 were damaged at the flexible side of the piloti story due to the high torsional irregularity. Based on these results, this study focuses on the problems of the seismic torsion design approach in current building codes.

• Earthquakes and Structures
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• v.12 no.3
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• pp.263-270
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• 2017

In this study, two geometrically identical multi-storey steel buildings with different lateral load resisting systems are structurally analyzed under same earthquake conditions and they are compared with respect to their construction costs of their structural systems. One of the systems is a steel structure with eccentrically steel braced frames. The other one is a RC wall-steel frame system, that is a steel framed structure in combination with a reinforced concrete core and shear walls of minimum thickness that the national code allows. As earthquake resisting systems, steel braced frames and reinforced concrete shear walls, for both cases are located on identical places in either building. Floors of both buildings will be of reinforced concrete slabs of same thickness resting on composite beams. The façades are assumed to be covered identically with light-weight aluminum cladding with insulation. Purpose of use for both buildings is an office building of eight stories. When two systems are structurally analyzed by FEM (finite element method) and dimensionally compared, the dual one comes up with almost 34% less cost of construction with respect to their structural systems. This in turn means that, by using a dual system in earthquake zones such as Turkey, for multi-storey steel buildings with RC floors, more economical solutions can be achieved. In addition, slender steel columns and beams will add to that and consequently more space in rooms is achieved.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.259-260
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• 2012

As RC structures in the marine environment rapidly increase, the interest and the importance of Chloride Penetration durable design have been growing. However, there is hardly any domestic Chloride Penetration durability of RC structures designed analysis programs. Currently, Chloride Penetration durable design method is studied and launched actively as a program in the United States, Europe, Japan and etc., but it is limited to Chloride Penetration durability of RC structures excluded from maintenance construction. Also, the level of dependence on the foreign technology is high; the foreign program is imported and used when needed. The main objective is to compare and to evaluate with the durability assessment program and several conditions when considering the design of Chloride Penetration durability through the programs developed abroad.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.331-340
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• 2021

The blast damage behavior of reinforced concrete (RC) structures exposed to unexpected extreme loading was investigated. To enhance the accuracy of numerical simulation for blast loading on RC structures with seven blast points, the calculation of blast loads using the Euler-flux-corrected-transport method, the proposed Euler-Lagrange coupling method for fluid-structure interaction, and the concrete dynamic damage constitutive model including the strain rate-dependent strength and failure models was implemented in the ANSYS-AUTODYN solver. In the analysis results, in the case of 20 kg TNT, only the slab member at three blast points showed moderate and light damage. In the case of 100 kg TNT, the slab and girder members at three blast points showed moderate damage, while the slab member at two blast points showed severe damage.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.253-256
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• 2008

The objective of this study is to evaluate the seismic weakness of existing nonseismic low-rise piloti-type apartment buildings which have the irregularities of weak story, soft story, and torsion simultaneously. A prototype 4-story RC building was selected, analyzed using linear dynamic procedure and finally evaluated according to the acceptance criteria of FEM356. This building satisfies the criteria.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.4
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• pp.221-229
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• 2019

Several water tanks installed in the building were damaged during the Gyeongju earthquake (2016) and the Pohang earthquake (2017). Since a water tank for fire protection is very important component, seismic safety should be ensured. In this study, an interaction between a water tank and a building was studied by the dynamic analysis of the RC building with the water tank. In case the water tank was installed on the roof of the RC building, it was confirmed that it did not significantly affect the response of the building. Based on the result, dynamic response characteristics of the water tank in the building were studied using two SDOF models represented dynamic behavior of the water tanks under earthquake. An earthquake time-history analysis was carried out with variables of aspect ratio of the tank, story of the building, and installed location in the building using three kinds of earthquakes.

• Korean Journal of Construction Engineering and Management
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• v.16 no.5
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• pp.12-20
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• 2015

Construction industry pays attention to modular construction recently which based on factory production not on labor intensive site production. Since modular construction has high time shortening effect and easiness of demolition and recycling, it has been applied to the temporary residential building. Domestic modular construction market are not activated yet, however, due to the high initial cost to realize modular construction. This study proposes demand-sensitized movable modular building in order to reduce the financial burden. The study compares between RC method building and Modular building which moves building when the demand falls off from Life-Cycle Cost's viewpoint. As a result of the economical evaluation, RC method achieved profits faster than Modular model, but Modular model's gross earnings during the life-cycle are much bigger than RC method. In other words, the result means that the market-sensitized movement of the modular building would be an economci choice in Life-Cycle Costing aspect.