• Structural Engineering and Mechanics
• /
• v.24 no.3
• /
• pp.323-337
• /
• 2006

In this paper, the hysteretic behaviors of channel and C-section cold-formed steel members (CFSMs) under cyclic axial loading were simulated with the finite element method. Geometric and material nonlinearities, Bauschinger effect, strain hardening and strength improvement at corner zones were taken into account. Extensive numerical results indicated that, as the width-to-thickness ratio increases, local buckling occurs prematurely. As a result, the hysteretic behavior of the CFSMs degrades and their energy dissipation capability decreases. Due to the presence of lips, the hysteretic behavior of a C-section steel member is superior to that of its corresponding channel section. The intermediate stiffeners in a C-section steel member postpone the occurrence of local buckling and change its shapes, which can greatly improve its hysteretic behavior and energy dissipation capability. Therefore, the CFSMs with a large width-to-thickness ratio can be improved by adding lips and intermediate stiffeners, and can be used more extensively in residential buildings located in seismic areas.

• Steel and Composite Structures
• /
• v.20 no.3
• /
• pp.501-512
• /
• 2016

High-strength structural bolts have been utilized for beam-to-column connections in steel-framed structural buildings. Failure of these components may be caused by the bolt shank fracture or threads stripping-off, documented in the literature. Furthermore, these structural bolts are galvanized for corrosion resistance or quenched-and-tempered in the manufacturing process. This paper adopted the finite element simulation to demonstrate discrete mechanical performance for these bolts under tensile loading conditions, the coated and uncoated numerical model has been built up for two numerical integration methods: explicit and implicit. Experimental testing and numerical methods can fully approach the failure mechanism of these bolts and their ultimate load capacities. Comparison has also been conducted for two numerical integration methods, demonstrating that the explicit integration procedure is also suitable for solving quasi-static problems. Furthermore, by using precise bolt models in T-Stub, more accurately simulate the mechanical behavior of T-Stub, which will lay the foundation of the mechanical properties of steel bolted joints.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.236-240
• /
• 2009

Dry wall using steel stud has the advantage of possibility to install various building, so it used to many buildings inside and outside of the country very rapidly. Though Light gauge steel framed housing offers many advantages to the consumer and the builder, the use of steel studs in wall system cause thermal problems such as thermal performance and pattern staing on walls. The present study has been conducted to observe effect of stud by the shape, and two kind of stud is made for this test to compare thermal performance. The test was conducted by setting those stud on the chamber and heating them. As the results of test and photograping by using TVS, there was temperature gap of each stud, and surface temperature of each section was appeared differently due to shape of stud delaying thermal bridge.

• Earthquakes and Structures
• /
• v.13 no.6
• /
• pp.539-549
• /
• 2017

Existing reinforced concrete frame buildings designed for vertical loads could only suffer severe damage during earthquakes. In recent years, many research activities were undertaken to develop a reliable and practical analysis procedure to identify the safety level of existing structures. The Incremental Dynamic Analysis (IDA) is considered to be one of the most accurate methods to estimate the seismic demand and capacity of structures. However, the executions of many nonlinear response history analyses (NL_RHA) are required to describe the entire range of structural response. The research discussed in this paper deals with the proposal of an efficient Incremental Modal Pushover Analysis (IMPA) to obtain capacity curves by replacing the nonlinear response history analysis of the IDA procedure with Modal Pushover Analysis (MPA). Firstly, In this work, the MPA is examined and extended to three-dimensional asymmetric structures and then it is incorporated into the proposed procedure (IMPA) to estimate the structure's seismic response and capacity for given seismic actions. This new procedure, which accounts for higher mode effects, does not require the execution of complex NL-RHA, but only a series of nonlinear static analysis. Finally, the extended MPA and IMPA were applied to an existing irregular framed building.

• Structural Engineering and Mechanics
• /
• v.41 no.6
• /
• pp.691-710
• /
• 2012

One of the most popular and commonly used strengthening techniques to protect against earthquakes is to infill the holes in reinforced concrete (RC) frames with fully reinforced concrete infills. In some cases, windows and door openings are left inside infill walls for architectural or functional reasons during the strengthening of reinforced concrete-framed buildings. However, the seismic performance of multistory, multibay, reinforced concrete frames that are strengthened by reinforced concrete wing walls is not well known. The main purpose of this study is to investigate the experimental behavior of vulnerable multistory, multibay, reinforced concrete frames that were strengthened by introducing wing walls under a lateral load. For this purpose, three 2-story, 2-bay, 1/3-scale test specimens were constructed and tested under reversed cyclic lateral loading. The total shear wall (including the column and wing walls) length and the location of the bent beam bars were the main parameters of the experimental study. According to the test results, the addition of wing walls to reinforced concrete frames provided significantly higher ultimate lateral load strength and higher initial stiffness than the bare frames did. While the total shear wall length was increased, the lateral load carrying capacity and stiffness increased significantly.

• Earthquakes and Structures
• /
• v.7 no.3
• /
• pp.295-315
• /
• 2014

This paper presents the results of an analytical study on seismic reliability of viscoelastically damped frame systems in comparison with that of conventional moment resisting frame systems. In order to exhibit the reliability of the frame systems with viscoelastic dampers, seismic reliability analyses were carried out for steel framed buildings, 5 and 12 storeys in height, designed as: (a) Case 1: Conventional moment resisting frame, (b) Case 2: Frame with viscoelastic dampers providing supplemental effective damping ratio of 10%, and (c) Case 3: Frame with viscoelastic dampers providing supplemental effective damping ratio of 20%. Nonlinear time history analyses were utilized to develop seismic fragility curves whilst monitoring various performance objectives. To obtain robust estimators of the seismic reliability, a database including 15 natural earthquake ground motion records with markedly different characteristics was employed in the fragility analysis. The results indicate that depending upon the supplemental effective damping ratio, frames designed with viscoelastic dampers have considerably lower annual probability of exceedance of performance limit states for structural components, showing up to a five-fold reduction in comparison to conventionally designed moment resisting frame system.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.36 no.5
• /
• pp.137-146
• /
• 2020

In this study, an experimental research was performed to find the characteristics of the lateral load resistance of perforated steel plates which could be developed to retrofit existing RC framed buildings. The Specimens are tested with variables such as aspect ratio of plate, the ratio of perforation area, and the ratio of perforated diameter to strip which is more than 0.6. The lateral load was applied with displacement control until to reach 3.5% drift ratio. Through the experimental results, it was shown that the maximum strength of all specimens were reached at around 0.5% drift ratio and maintained until 3.5% drift ratio. From results, the modified strength prediction formula was derived with the variable ratio of the perforated diameter to strip. To evaluate seismic retrofit performance of RC frames using perforated steel plate, a simple design process was presented.

• Journal of architectural history
• /
• v.33 no.4
• /
• pp.7-16
• /
• 2024

This study sought to reveal the architectural characteristics of Quonset church built in the Archdiocese of Gwangju, and the conclusions are as follows. The Quonset structure, which was used as a military barracks during World War II and was designed to be easily assembled and disassembled quickly, was used in Damyang, Hwasun, and Gokseong churchs. They were all built in 1958, after the Korean War, and can be related to the historical background of the rapid increase in the number of Catholics. They are utility buildings that can accommodate many believers, that is, large quonsets measuring 40 feet (width) x 100 feet (length). The floor plan was largely divided into two spaces, with about 3/4 reserved for the nave and altar, and the remaining 1/4, or 24 to 30 feet, used as a sacristy or confessional. The cross-section is a semicircle with a radius of 20 feet, framed by 6-inch ribs, and its unique structure, in which bricks are stacked on the outside to form the exterior, makes it different from a typical brick church. Unlike other stone churches built around the same time, Quonset church was not expanded. This may be due to the difficulty in supplying special materials such as the ribs that make up the frame, as well as the absence of relevant experts.

• Korean Journal of Heritage: History & Science
• /
• v.48 no.2
• /
• pp.120-141
• /
• 2015

This paper is a preliminary study of architectural characteristics of Jangdae (general's podium), which shows one of the technical changes in fortification of Joseon Dynasty. As a facility for commands of generals and training for officers and men, it was located inside a fortress. Although it is not certain when the first Jangdae was built, the number of them dramatically increased around 18th century. Since the top priority function of the Jangdae was the prospect, it was installed at the hilly spot with open architecture. In addition, the open structure of Eupseong fortress towers on the riverside banks could simultaneously offer the functions as viewing around and Jangdae. Since Jangdae was also a place for military drills and reviews of soldiers, a wide podium was positioned at the front to muster the soldiers. This feature was standardized in the space organization of Jangdae in Joseon, and a mere podium was installed unless the topographic restrictions allows enough space. On the other hand, as a place for a commander, the hierarchy of the Jangdae was revealed through a variety of architectural characteristics. The hierarchy was assigned to the commander's space through the altitude difference, and diverse ornaments were added to show a sense of class. The floor plan of the Jangdae building can be largely categorized into rectangle and square, and the typical sizes of the former are $5{\times}4$ Kans (traditional measuring unit between two columns) and $3{\times}2$ Kans. Out of these two types, buildings of $5{\times}4$ Kans were found in flat land and eupseong fortresses with large space, and the relatively smaller ones of $3{\times}2$ Kans in mountain fortresses. All buildings of square floor plan had $3{\times}3$ Kans style, and the center Kan was twice wider than the side Kan to make the central space wide. It seems that the purpose was to secure the interior space of the upper story because the center Kan accounts for the floor area of the upper story. Some Jangdae's had internal story to form overhead space. The multi-roofed tower style with eaves attached to the upper and lower story is found exclusively in Jangdae. The buildings shows the Onkanmulim style which extends Naejinju (inner column) of the lower story to be the Byeonju (outer column) of the upper story, and the log-framed floor in the upper floor was structured by inserting the Changbang (connecting beam) between the Naejinju's and joining the log frames. In addition, the towers in eupseong fortresses had log-framed floor in the upper floor by setting up the high Nuhaju (column underneath a roof) and joining Cheongbang to the upper part of the column while it cannot be regarded as multi-roofed because only the upper part has a roof.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.1
• /
• pp.167-175
• /
• 2018

This research deals, The characteristics of mechanics and behavior of the tube structural systems, It has been investigated and considered conventional theory and case models, It has shown the suitability, The best location, And optimal shape of the unit module system, Considered variables materials of stiffness increase and decrease in hybrid tube structural systems this study carried out adapting analysis of statistical concepts. In a concrete way, This study exams the effect of reducing horizontal displacement and the shear lag phenomenon, Also, The purpose of this study is to utilize the basic data on the design and study of future high-rise hybrid structural system using this research. As a result, The framed- tube structural system does not effectively cope with horizontal behavior of high-rise buildings, The results of using varying material tested resistance factors and lateral loads in hybrid tube structural system, When each material is compared Bracing material is identified as a key factor in lateral behavior. In a ratio of material quantity framed-tube structural system, The level of sensitivity affecting the horizontal displacement is greater then the beam's column, In case of braced tube structural system, Braced appeared to be most sensitive in comparison of material quantity ratio in columns and beams.