• Wind and Structures
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• v.13 no.5
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• pp.413-431
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• 2010

The focus of this article is on the assessment of vertical wind vector components and their aerodynamic impact on lattice framework, specifically two distinct sections of a guyed transmission tower. Thunderstorm winds, notably very localized events such as convective downdrafts (including downbursts) and tornadoes, result in a different load on a tower's structural system in terms of magnitude and spatial distribution when compared to horizontal synoptic winds. Findings of previous model-scale experiments are outlined and their results considered for the development of a testing rig that allows for rotation about multiple body axes through a series of wind tunnel tests. Experimental results for the wind loads on two unique experimental models are presented and the difference in behaviour discussed. For a model cross arm with a solidity ratio of approximately 30%, the drag load was increased by 14% when at a pitch angle of $20^{\circ}$. Although the effects of rotation about the vertical body axis, or the traditional 'angle of attack', are recognized by design codes as being significant, provisions for vertical winds are absent from each set of wind loading specifications examined. The inclusion of a factor to relate winds with a vertical component to the horizontal speed is evaluated as a vertical wind factor applicable to load calculations. Member complexity and asymmetric geometry often complicate the use of lattice wind loading provisions, which is a challenge that extends to future studies and codification. Nevertheless, the present work is intended to establish a basis for such studies.

• Journal of Korea Trade
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• v.24 no.6
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• pp.82-100
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• 2020

Purpose - This paper attempts to compare five free trade agreements with gender chapters ratified by Chile and Canada and derives lessons for Korea in terms of gender-aware trade policy. While Chile and Canada have three and two FTAs with gender chapter respectively, Korea has none so far, although it has already ratified an FTA with the two countries. Design/methodology - This study first investigates all the gender-provisions with the gender chapters, conducts a comparative analysis on the five chapters as well as a case study of one target FTA's implementation and achievements, and finally suggests policy implications for Korea's trade administration as well as trade-related agencies. Findings - According to the analysis, there are three phases in terms of advancement in gender-related trade policy. As Chile is in phase two and Canada is in phase three, Korea remains in phase one. It has a ministry related to gender within the government, but not within the OMT. It has statistics on female business, but not of women traders. It has a few gender-related provisions in its FTAs, but not a gender chapter. In this sense, new mandates related to gender-aware trade policy for OMT, KITA, and KOTRA should be provided to realize the concrete economic benefits resulting from empowering women traders and policies promoting them. Originality/value - Existing studies only focus on introducing gender-related international commitments and Korea's participation in them. This paper is the first attempt to compare actual gender chapters of five FTAs ratified by two countries with the most advanced gender chapters in the world. To gain benefits from the positive gender impact of trade agreements, negotiating and signing gender responsive FTA with future partners is one of the most efficient, as well as inclusive, trade policies urgently needed for Korea.

• International Journal of High-Rise Buildings
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• v.5 no.1
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• pp.1-12
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• 2016

The 1100 foot [335 m] tall Wilshire Grand Center tower under construction in Los Angeles illustrates many key outrigger issues. The tower has a long, narrow floor plan and slender central core. Outrigger braces at three groups of levels in the tower help provide for occupant comfort during windy conditions as well as safety during earthquakes. Because outrigger systems are outside the scope of prescriptive code provisions, Performance Based Design (PBD) using Nonlinear Response History Analysis (NRHA) demonstrated acceptability to the Los Angeles building department and its peer review panel. Buckling Restrained Brace (BRB) diagonals are used at all outrigger levels to provide stable cyclic nonlinear behavior and to limit forces generated at columns, connections and core walls. Each diagonal at the lowest set of outriggers includes four individual BRBs to provide exceptional capacities. The middle outriggers have an unusual 'X-braced Vierendeel' configuration to provide clear hotel corridors. The top outriggers are pre-loaded by jacks to address long-term differential shortening between the concrete core and concrete-filled steel perimeter box columns. The outrigger connection details are complex in order to handle large forces and deformations, but were developed with contractor input to enable practical construction.

• Advances in concrete construction
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• v.9 no.1
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• pp.23-31
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• 2020

Geometric nonlinearity can significantly affect load-carrying capacity of slender columns. Dependence of structural stability on columns necessitates the consideration of second-order effects in the design process of columns, appropriately. On the whole, the design codes present a simplified procedure for second order analysis of slender columns. In this approximate method, the end moments of columns resulted from linear analysis (first-order) are multiplied by the recommended moment amplification factors of codes to achieve magnified moments of the second-order analysis. In the other approach, the equilibrium equations are directly solved for the deformed configuration of structure, so the resulting moments and deflections contain the influence of slenderness and increase more rapidly than do loads. The aim of this study is to evaluate the accuracy of moment amplification factors of Iranian national building code whose provisions are similar to the ACI requirement. Herein, finite element method is used to achieve magnified end moments of reinforced concrete moment resisting frames, and the outcomes are compared with the moments acquired based on the proposed approximate method by Iranian national building code. The results show that the approximate method of Iranian code for calculating magnified moments has significant errors for both unbraced and braced columns.

• Steel and Composite Structures
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• v.24 no.1
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• pp.93-112
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• 2017

Metaheuristic algorithms in general make use of uniform random numbers in their search for optimum designs. Levy Flight (LF) is a random walk consisting of a series of consecutive random steps. The use of LF instead of uniform random numbers improves the performance of metaheuristic algorithms. In this study, three discrete optimum design algorithms are developed for steel skeletal structures each of which is based on one of the recent metaheuristic algorithms. These are biogeography-based optimization (BBO), brain storm optimization (BSO), and artificial bee colony optimization (ABC) algorithms. The optimum design problem of steel skeletal structures is formulated considering LRFD-AISC code provisions and W-sections for frames members and pipe sections for truss members are selected from available section lists. The minimum weight of steel structures is taken as the objective function. The number of steel skeletal structures is designed by using the algorithms developed and effect of LF is investigated. It is noticed that use of LF results in up to 14% lighter optimum structures.

• Structural Engineering and Mechanics
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• v.67 no.6
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• pp.671-682
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• 2018

The effect of earthquake induced torsion, due to mass eccentricities, is investigated with the objective of providing practical design guidelines for minimizing the torsional response of building structures. Current code provisions recommend performing three dimensional static or dynamic analyses, which involve shifting the centers of the floor masses from their nominal positions to what is called an accidental eccentricity. This procedure however may significantly increase the design cost of multistory buildings, due to the numerous possible spatial combinations of mass eccentricities and it is doubtful whether such a cost would be justifiable. This paper addresses this issue on a theoretical basis and investigates the torsional response of asymmetric multistory buildings in relation to their behavior when all floor masses lie on the same vertical line. This approach provides an insight on the overall seismic response of buildings and reveals how the torsional response of a structure is influenced by an arbitrary spatial combination of mass eccentricities. It also provides practical guidelines of how a structural configuration may be designed to sustain minor torsion, which is the main objective of any practicing engineer. A parametric study is presented on 9-story common building types having a mixed-type lateral load resisting system (frames, walls, coupled wall bents) and representative heightwise variations of accidental eccentricities.

• Journal of architectural history
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• v.28 no.6
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• pp.67-76
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• 2019

The purpose of this study is to identify the context of enactment and the application to the design of in 1916. The characteristics of the composition are as follows; First, One-third are general rules of common application, Second, regulations related to cold resistance are set up separately, last, each of the 21 articles was equally divided for schools, hospitals and prisons. The standard reflect the times of the mid-1910s. The Trend of using of the Western Building System in the 1910s, The need for building construction against cold weather, and Actual conditions of renovation, extension and new plans by facility. Furthermore, the fact that various regulations concerning standard design were enacted and used in various Japanese institutions around the 1910s may have influenced the establishment of the standard. Meanwhile, after checking the status of the reflection of the standard on the planning drawings of the government facilities around 1916, it was also found that the plan was carried out in compliance with the provisions of the standard, and that the items already applied before the enactment had been organized into architectural standards.

• International Journal of High-Rise Buildings
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• v.1 no.3
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• pp.211-220
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• 2012

The current 2002 Indonesian Seismic Code consists of prescriptive criteria that are intended to result in buildings capable of providing certain levels of performance. However, the actual performance capability of buildings is not assessed as part of the code procedures. Several analysis procedures are allowed, and the state of practice is to use the RSA with six-zone seismic map developed for 475-year earthquake. This code is being revised and will adopt many of the ASCE7-10 provisions and 2475-year earthquake for MCE. The growth of tall buildings compels engineers to look for more optimal lateral system. The use of RC core wall as single system has been adopted by very few engineering firms, which is allowed in the current code but will no longer be the case if the new one is in effect. Other innovative structural system such as core wall and outrigger is not addressed in the proposed new code. Engineers must then resort to NLRHA. Currently, one 50-story building under construction using RC core wall and outrigger has been designed with RSA and employing capacity design principles, then evaluated using NLRHA per TBI Guidelines. Based on the evaluation, the performance of the 50-story building generally still meets the criteria of the TBI Guidelines. The result of the case study is presented in this paper.

• International Journal of High-Rise Buildings
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• v.1 no.3
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• pp.149-154
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• 2012

This paper presents a summary of the state of the practice for Performance Based Seismic Design (PBSD) in the United States. While it is not included in the prescriptive provisions of the United States' building codes, the PBSD procedure has been successfully implemented for two decades. The recent publication of the Guidelines for Performance-Based Seismic Design of Tall Buildings by the Pacific Earthquake Engineering Research Center (PEER) illustrates the fact that the engineering community has embraced this procedure and provides a thoughtful set of recommendations to building designers who intend to implement PBSD. The key parameters currently required for a PBSD also are outlined, such as seismic hazard definition, modeling procedures, and acceptance criteria. These Guidelines will serve as the basis for many PBSD projects in the coming years and as such are a common reference used throughout this paper. Finally, a brief summation of recent PBSD projects in the United States is presented.

• Journal of the Korean Geotechnical Society
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• v.30 no.8
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• pp.5-11
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• 2014

The objective of this paper is to develop a rational reliability analysis procedure for the LRFD design provisions of bridge substructures. A bridge abutments is considered in this study. The reliability analysis is applied to determine the relationship between the major design parameters for bridge abutment and reliability index. The considered load components include dead load, vertical and horizontal earth pressure, earth surcharge, and vehicle live load. Several limit states are considered: foundation bearing capacity, sliding, and overturning. The analysis results show that the most important parameter in the reliability analysis is the effective stress friction angle of the soil. The reliability indices are calculated using Monte Carlo simulations for a selected bridge abutment. The results of the sensitivity analysis indicate that reliability index is most sensitive with regard to resistance factor and horizontal earth pressure factor.