• Steel and Composite Structures
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• v.18 no.1
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• pp.121-134
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• 2015

This paper is to investigate the potentials of the elastic seismic design of twisted high-rise steel diagrid frame buildings in the strong wind and moderate/low seismicity regions. First, the prototypes of high-rise steel diagrid frames with architectural plans that have a twist angle of 0 (regular-shaped), 1, and 2 degrees were designed to resist wind. Then, the effects of the twist angle on the estimated quantities and structural redundancies of the diagrid frames were examined. Second, the seismic performance of the wind-designed prototype buildings under a low seismicity was evaluated. The response spectrum analysis was conducted for the service level earthquake (SLE) having 43-year return period and the maximum considered earthquake (MCE) having 2475-year return period. The evaluation resulted that the twisted high-rise steel diagrid frames resisted the service level earthquake elastically and most of their diagrid members remained elastic even under the maximum considered earthquake.

• Journal of the Korean earth science society
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• v.32 no.1
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• pp.152-157
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• 2011

Lg amplitude decrease $Q^{-1}$ becomes very important when harzadous earthquakes occurred in neighbor nations such as Japan and China because the Lg phase is the largest seismic phase in Korea. The values of Lg $Q^{-1}$ are correlated with seismic activities from the RTSM for IRIS data with long pair distance of stations and events. The Japanese paths crossing the East Sea (Sea of Japan) show high $Q^{-1}$ values related with seismicity and oceanic crust. The paths of Shanghai having the moderate seismicity show the second highest values followed by the Japanese region, while the paths between Manchuria and the Korean Peninsula exhibit low values associated with the low seismicity of the regions.

• Earthquakes and Structures
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• v.11 no.5
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• pp.741-777
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• 2016

A simplified approach of assessing torsionally balanced (TB) and torsionally unbalanced (TU) low-medium rise buildings of up to 30 m in height is presented in this paper for regions of low-to-moderate seismicity. The Generalised Force Method of Analysis for TB buildings which is illustrated in the early part of the paper involves calculation of the deflection profile of the building in a 2D analysis in order that a capacity diagram can be constructed to intercept with the acceleration-displacement response spectrum diagram representing seismic actions. This approach of calculation on the planar model of a building which involves applying lateral forces to the building (waiving away the need of a dynamic analysis and yet obtaining similar results) has been adapted for determining the deflection behaviour of a TU building in the later part of the paper. Another key original contribution to knowledge is taking into account the strong dependence of the torsional response behaviour of the building on the periodic properties of the applied excitations in relation to the natural periods of vibration of the building. Many of the trends presented are not reflected in provisions of major codes of practices for the seismic design of buildings. The deflection behaviour of the building in response to displacement controlled (DC) excitations is in stark contrast to behaviour in acceleration controlled (AC), or velocity controlled (VC), conditions, and is much easier to generalise. Although DC conditions are rare with buildings not exceeding 30 m in height displacement estimates based on such conditions can be taken as upper bound estimates in order that a conservative prediction of the displacement profile at the edge of a TU building can be obtained conveniently by the use of a constant amplification factor to scale results from planar analysis.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1391-1404
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• 2016

Peninsular Malaysia lying on the stable Sunda Plate has traditionally been considered safe with low to moderate seismicity. However, far field Sumatran mega-earthquakes have been shown to be capable of triggering ground motions felt in high rise structures in the major Malaysian cities while seismic impact from local earthquakes of moment magnitude 3.8 have reportedly induced nominal structural damages to nearby buildings. This paper presents an overview of the recent seismic activities in and around Peninsular Malaysia with reference to prominent earthquakes generated by far field interplate and local intraplate sources. Records of ground motion data and seismic hazard assessment (SHA) results available in the literature have been analyzed and discussed. The peak ground acceleration (PGA) values from historical records for few local intraplate events were observed to be higher than those for the events from Sumatran Subduction Zone. This clearly points to the need for a detailed and comprehensive SHA incorporating both far field and local sources. Such an analysis would contribute the knowledge required for secure and reliable infrastructure design and safeguard the Malaysian people and economy.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.871-876
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• 2001

Recent earthquakes in California and Japan caused extensive damage to highway bridge structures. It is also thought that during probable earthquakes bridge structures in Korea could be failed due to the structural deficiencies, which were nonseismically designed and constructed before 1992. In these regards, innovative strengthening methods have been developed to repair reinforced concrete bridge columns, especially by glassfiber sheet bonding methods which are widely used today. The primary objective of this research is to investigate the seismic behavior of RC bridge columns retrofitted with composite straps and to propose pertinent guidelines of repair and rehabilitation method for earthquake resistant design procedure of RC bridges which are located in low or moderate seismicity regions. Six scaled-down concrete test specimens were made with test variables such as lap splice ratio, axial force ratio, confinement ratio, composite straps in the plastic hinge region. Pertinent design guidelines could be developed for the earthquake resistant design of RC bridge piers retrofitted with glassfibers in low or moderate seismic region.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.319-331
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• 1999

The seismic hazard of Korea is briefly described. The seismic design requirements design earthquake levels and design response spectrum that are going to be adopted in the future code system are introduced. Characteristics of ground motion and seismic responses of structures in low to moderate seismicity regions are briefly described. The concept of limited ductility design that seems appropriate for the seismic design in Korea is explained.

• Earthquakes and Structures
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• v.5 no.6
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• pp.625-655
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• 2013

This paper investigated the seismic behaviour of an innovated non-ductile precast concrete wall structural system; namely HC Precast System (HCPS). The system comprises load-bearing precast wall panels merely connected only to column at both ends. Such study is needed because there is limited research information available in design codes for such structure particularly in regions having low to moderate seismicity threats. Experimentally calibrated numerical model of the wall system was used to carry out nonlinear pushover analyses with various types of lateral loading patterns. Effects of laterally applied single point load (SPL), uniformly distributed load (UDL), modal distributed load (MDL) and triangular distributed load (TDL) onto global behaviour of HCPS were identified. Discussion was focused on structural performance such as ductility, deformability, and effective stiffness of the wall system. Thus, a new method for engineers to estimate the nonlinear deformation of HCPS through linear analysis was proposed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.60-67
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• 2004

The designer of a tall building even in moderate and low seismic regions should, in finalizing the desist consider the probable impact of the design basis earthquake on the selected structural system. In this study, seismic response analysis was conducted to evaluate the seismic performance of concentrically braced steel highrise buildings which were designed only for governing wind loading under moderate seismicity. The main purpose of this analysis was to see if the wind design would create a system whose elastic capacity clearly exceeds the probable demand as suggested by the design basis earthquake. The strength demand-to-capacity study revealed that the wind-designed steel highrise buildings with the aspect ratio of larger than five can withstand the design basis earthquake elastically by a sufficient margin due to the system over-strength resulting from the wind-serviceability criterion. The maximum story drift demand from the design basis earthquake was just 0.25% (or half the limit of Immediate Occupancy performance level in FEMA 273)

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.4
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• pp.33-42
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• 2007

This paper describes the state-of-the art research activities on seismic isolation systems for improving the seismic capacities of the bridges in Korea. Though Korea is located in a region of low-to-moderate seismicity, the construction of seismic isolation systems has increased rapidly. The application of seismic isolation system has become popular worldwide because of its stable behavior and economical construction especially for bridge structures. Since optimal reliability level of isolated bridges can be determined as the one that provides the highest net life-cycle benefit to society, or the minimum Life-Cycle Cost (LCC), an optimal design procedure based on minimum LCC concept is more expedient for the design of seismically isolated bridges in areas of low-to-moderate seismicty. To verify the adequacy of the new design concept based on the LCC minimization, experimental studies on seismically isolated bridge are introduced as well, which include pseudo-dynamic test of scaled pier and dynamic field test of full-scale. With the application of seismic isolation systems, many kinds of dampers to improve the seismic capacity of structure are also applied not only to new bridges but also to existing bridges.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.6
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• pp.351-360
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• 2016

In regions of low-to-moderate seismicity, various types of lap splices are used for longitudinal reinforcement of columns at the plastic hinge zones. The seismic performance of such lap spliced columns, such as strength, deformation capacity, and energy dissipation, is affected by material strengths, longitudinal re-bar size, confinement of hoops, lap splice location, and lap splice length. In the present study, cyclic loading tests were performed for columns using three types of lap splices (bottom offset bar splice, top offset bar splice, and splice without offset bend). Lap splice length($40d_b$ and $50d_b$) was also considered as test parameters. Ties with 90-degree end hooks were provided in the lap splice length. The test results showed that strength, deformation capacity, and energy dissipation of columns significantly differed depending on the details and the length of lap splices. The bottom offset bar splice showed high ductility and energy dissipation but low strength; on the other hand, the top offset bar splice and the splice without offset bend showed high strength but moderate ductility and energy dissipation.