• Journal of the Korean Society for Precision Engineering
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• v.32 no.11
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• pp.997-1005
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• 2015

In this study, modal analysis and equivalent static load analysis for valve supports of 26" gas piping in gas stations were conducted and the existing straight and inclined types of valve supports were compared using seismic performance testing. Also, a new valve support shape was suggested by optimizing position of fastener holes, width and thickness of the support, and size of bracket. Improvement in seismic performance by design optimization was verified through equivalent static load analysis. The seismic performance of the newly proposed valve support was greatly improved and the maximum displacement and maximum stress of the seismic load was about 20% lower than those of the existing valve support.

• Structural Engineering and Mechanics
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• v.4 no.5
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• pp.497-511
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• 1996

The equivalent static force procedure and the response spectrum analysis method are widely used for seismic analyses of multi-story buildings. The equivalent static force procedure is one of the most simple but less accurate method in predicting possible seismic response of a structure. The response spectrum analysis method provides more accurate results while it takes much longer computational time. In the response spectrum method, dynamic response of a multi-story building is obtained by combining modal responses through a proper procedure such as SRSS or CQC method. Since all of the analysis results are expressed in absolute values, structural engineers have difficulties to combine them with the results obtained from the static analysis. Design automation is interrupted at this stage because of the difficulty in the decision of the most critical design load. Pseudo-dynamic analysis method proposed in this study provides more accurate seismic analysis results than those of the equivalent static force procedure since the dynamic characteristics of a structure is considered. And the proposed method has an advantage in combination of the analysis results due to gravity loads and seismic loads since the direction of the forces can be considered.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1239-1243
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• 2009

To evaluate the structural integrity of the nuclear seismic category penetration cooling water pump under the seismic service conditions the seismic analysis was performed in accordance with IEEE-STD-344 code. The finite element computer program, ANSYS, Version 10.0, is used to perform both a mode frequency analysis and an equivalent static seismic analysis of the pump assembly. The mode frequency analysis results show the fundamental natural frequency is greater than 33 Hz and does not exist in seismic range, thus justifying the use of the static analysis. The stresses resulted from various loadings and their combinations are within the allowable limits specified in the above mentioned IEEE code. The results of the seismic evaluation fully satisfied the structural acceptance criteria of the IEEE code. Accordingly the structural integrity on the pump assembly was proved.

• Structural Engineering and Mechanics
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• v.23 no.6
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• pp.635-649
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• 2006

The static and dynamic responses of guyed telecommunication towers can be determined by using two models, the space truss element model, and the equivalent beam-column element model. The equivalent beam-column analysis is based on the determination of the equivalent shear, torsion, and bending rigidities as well as the equivalent area of the guyed mast. In the literature, two methods are currently available to determine the equivalent properties of lattice structures, namely: the unit load method, and the energy approach. In this study, an equivalent beam-column analysis is introduced based on an equivalent thin plate approach for lattice structures. A finite-element modeling, using suitably modified ABAQUS software, is used to investigate the accuracy of utilizing the different proposed methods in determining the static and dynamic responses of a guyed tower of 364.5-meter high subjected to static and seismic loading conditions. The results from these analyses are compared to those obtained from a finite-element modeling of the actual structure using 3-D truss and beam elements. Good agreement is shown between the different proposed beam-column models, and the model of the actual structure. However, the proposed equivalent thin plate approach is simpler to apply than the other two approaches.

• Journal of Korean Association for Spatial Structures
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• v.9 no.4
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• pp.49-59
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• 2009

The seismic responses of small-scale spatial frames such as school gymnasiums are usually evaluated using static analysis, although time-history analysis should be carried out to fully incorporate the dynamic responses of the structures against seismic motions. In this study, advanced static analysis procedures arc presented for school gymnasiums that will improve the performance evaluation against seismic motions. The seismic loads are approximated by equivalent static loads corresponding to the two performance levels; i.e., Levels 1 and 2 defined by the Japanese building standard. The importance of utilizing the eigenmode in the load pattern is discussed. Simple static analysis procedures are presented for evaluation of maximum vertical acceleration. It is shown that the static analysis for Level 2 input significantly underestimates the responses by dynamic analysis; however, the inelastic responses for Level 2 are shown to be successfully evaluated using the equivalent linearization that is similar to the $^{\circ}$Dmethod based on calculation of limit strength$^{\circ}{\pm}$ for building frames in Japan.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.224-231
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• 2003

The purpose of this study is to review and validate the seismic analysis procedures of turbine-generator foundation specified in the Korea Building Code which adopts equivalent static analysis. Typical machines and foundations were chosen and various kinds of parametric studies were peformed and the results were compared with the detail dynamic analysis. The general trend of the study results showed that the most of the computed responses of equivalent static analysis are smaller than those of the dynamic analyses(response spectrum analysis and time history analysis), which implies the existing seismic analysis technique using the existing Building Code may give unconservative design results. The results also showed that the seismic loads are one of the governing design parameters of the turbine-generator foundations.

• Earthquakes and Structures
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• v.15 no.1
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• pp.81-95
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• 2018

Most buildings feature core walls (and shear walls) that are placed eccentrically within the building to fulfil architectural requirements. Contemporary earthquake design standards require three dimensional (3D) dynamic analysis to be undertaken to analyse the imposed seismic actions on this type of buildings. A static method of analysis is always appealing to design practitioners because results from the analysis can always be evaluated independently by manual calculation techniques for quality control purposes. However, the equivalent static analysis method (also known as the lateral load method) which involves application of an equivalent static load at a certain distance from the center of mass of the buildings can generate results that contradict with results from dynamic analysis. In this paper the Generalised Force Method of analysis has been introduced for multi-storey buildings. Algebraic expressions have been derived to provide estimates for the edge displacement ratio taking into account the effects of dynamic torsional actions. The Generalised Force Method which is based on static principles has been shown to be able to make accurate estimates of torsional actions in seismic conditions. The method is illustrated by examples of two multi-storey buildings. Importantly, the black box syndrome of a 3D dynamic analysis of the building can be circumvented.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.75-80
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• 2017

In this study, seismic performance of various types of valve supports in terms of flexural rigidity are evaluated by FEA using equivalent static load method. Flexural rigidity of the existing two types of valve supports can be effectively improved by simply adding one more bracket on the other side of support. New types of polygonal valve supports with a concept of fully stressed beam theory are suggested and it is verified that the new supports are rigid enough to withstand stronger earthquake which we should be prepared for.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.697-704
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• 2019

The public has grown more anxious towards domestic earthquakes that have been taking place since 2000, and regulations on seismic design has been strengthened. Out of 4,605 Air Force installations that require the application of seismic design, 2,982 remain unapplied. By taking budget issues and the time spent to implement seismic retrofit into account, this paper aims to list up seismic reinforcement priorities for airmen dormitories where they can potentially be most vulnerable to earthquakes. The priorities are extracted based on Data Envelope Analysis(DEA). To apply DEA, two sets of variables are set: seismic reinforcement costs as input variable: age of building, number of residents, and seismic load as output variables. At the end, suggestions are made for developing seismic reinforcement plans that can be applied to all Air Force installations.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.63-72
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• 2001

In this paper, to satisfy the safety and economy immediately, we assume the center of lateral load in case the dynamic motion of the torsionally unbalanced structure is transformed into the static lateral load using modal analysis and proposes a method to control the design eccentricity in order to make the center of lateral load coincide with the center of strength. And when the structure is designed by proposed method, it is shown that the structure designed by proposed method does not demand excessive additional ductility in comparison with the structure designed by provisions of other seismic building code.