• Advances in nano research
• /
• v.8 no.4
• /
• pp.323-333
• /
• 2020

In recent years, there has been an upsurge for the usage of buckling restrained braces (BRB) rather than ordinary braces, as they have evidently performed better. If the overall brace buckling is ignored, BRBs are proven to have higher energy absorption capacity and flexibility. This article aims to deliberate an economically efficient yet adequate type of all-steel BRB, comprised of the main components as in traditional ones, such as : (1) a steel core that holds all axial forces and (2) a steel restrainer tube that hinders buckling to occurr in the core; there is a more practical detailing in the BRB system due to the elimination of a filling mortar. An investigation has been conducted for the proposed rectangular-tube core BRB and it is hysteric behavioral results have been compared to previous researches conducted on a structure containing a similar plate core profile that has the same cross-sectional area in its core. A loss of strength is known to occur in the BRB when the limiting condition of local buckling is not satisfied, thus causing instability. This typically occurs when the thickness of the restrainer tube's wall is smaller than the cross-sectional area of the core plate or its width. In this study, a parametric investigation for BRBs with different formations has been performed to verify the effect of the design parameters such as different core section profiles, restraining member width to thickness ratio and relative cross-sectional area of the core to restrainer, on buckling load evaluation. The proposed BRB investigation results have also been presented and compared to past BRB researches with a plate profile as the core section, and the advantages and disadvantages of this configuration have been discussed, and it is concluded that BRBs with tubular core section exhibit a better seismic performance than the ones with a plate core profile.

• Journal of Korean Society of Steel Construction
• /
• v.17 no.3 s.76
• /
• pp.325-335
• /
• 2005

This study tackles the development of an improved detail of partially restrained CFT square column-to-beam connection and the evaluation of its mechanical behavior under monotonic loading. The connection is designed to strengthen shearing capacity at the bottom of the connection due to the ultimate behavior of PR-CC by its detail of the bottom connection and simplify the fabrication process. The suggested connection is the welded bottom beam flange connection(M-2) and is compared with the existing PR-CC of bolted seat angle connection(M-1). Two specimens were fabricated in actual size and tested under monotonic loading. Based on the test results, the welded bottom beam flange connection exhibited about 85% of the stiffness of steel beam. It was similar to the bolted seat angle connection and behaved as PR-CC. The specimen of the supposed connection type failed at the shear connection of web but was similar to the bolted seat angle connection until the failure. It obtained sufficient stiffness and capacity through the reinforcingsteel and the capacity and deformational ability equivalent to the full-plastic moment through the anchor inside the steel tube at the web connection. So, it can be said that the suggested connection exhibits sufficient ductile behavior.

• Steel and Composite Structures
• /
• v.49 no.5
• /
• pp.517-532
• /
• 2023

Tower structures have been widely used in communication and transmission engineering. The failure of joints is the leading cause of structure failure, which make it play a crucial role in tower structure engineering. In this study, the aluminum alloy three tube tower structure is taken as the prototype, and the middle joint of the tower was selected as the research object. Three different stainless steel-aluminum alloy composite joints (SACJs), denoted by TA, TB and TC, were designed. Finite element (FE) modeling analysis was used to compare and determine the TC joint as the best solution. Detail requirements of fasteners in the TC stainless steel-aluminum alloy composite joint (TC-SACJ) were designed and verified. In order to systematically and comprehensively study the mechanical properties of TC-SACJ under multi-directional loading conditions, the full-scale experiments and FE simulation models were all performed for mechanical response analysis. The failure modes, load-carrying capacities, and axial load versus displacement/stain testing curves of all full-scale specimens under tension/compression loading conditions were obtained. The results show that the maximum vertical displacement of aluminum alloy tube is 26.9mm, and the maximum lateral displacement of TC-SACJs is 1.0 mm. In general, the TC-SACJs are in an elastic state under the design load, which meet the design requirements and has a good safety reserve. This work can provide references for the design and engineering application of aluminum alloy tower structures.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.8
• /
• pp.411-419
• /
• 2016

The objective of this study was to evaluate the application possibility of tube type electrolysis module system using recirculation process through removal organic matters and nitrogen in the pigment wastewater. The tube type electrolysis module consisted of a inner rod anode and an outer tube cathode. Material used for anode was titanium electroplated with $RuO_2$. Stainless steel was used for cathode. It was observed that the pollutant removal efficiency was increased according to the decrease of flowrate and increase of current density. When the retention time in tube type electrolysis module system was 180 min, chlorate concentration was 382.4~519.6 mg/L. The chlorate production was one of the major factors in electrochemical oxidation of tube type electrolysis module system using recirculation process used in this research. The pollutant removal efficiencies from the bench scale tube type electrolysis module system using recirculation operated under the electric charge of $4,500C/dm^2$ showed the $COD_{Mn}$ 89.6%, $COD_{Cr}$ 67.8%, T-N 96.8%, and Color 74.2%, respectively and energy consumption was $5.18kWh/m^3$.

• Journal of Korean Society of Steel Construction
• /
• v.11 no.1 s.38
• /
• pp.43-54
• /
• 1999

The divergence connection between steel circular tubes is widely used in such structures as factory facilities, steel circular hollow section truss, and off-shore tower. Steel circular hollow section (SCHS) have close section, and it makes their per-unit production expense higher than open sectioned products like L-shape, H-shape steels, but the sectional resistance of SCHS against vertical compression and torsion is very high. Despite the structural merits of SCHS, however, many engineers dislike to use them in their design because of uncertainty regarding the stress distribution and deformation behavior at their connections. Therefore, this thesis dealt with X-type connections, the most common forms of connection, and studied their load-deformation relationship. It observed how to show the load-deformation relationship at steel circular tube connections according to the diameter-thickness ratio (D/T) of the chord and diameter of branch-diameter of chord ratio (d/D) and suggested prediction yield load using by ring analysis method.

• Land and Housing Review
• /
• v.2 no.1
• /
• pp.47-52
• /
• 2011

Recent advances of technology in materials science have made it easy to respond to user's needs on high performance steel in civil and building structures. The high-performance and high-strength steel are required for large scale structure and high-rise building to have high-strength, high fracture toughness and better weldability etc. Therefore development of 600MPa class steel for mega structure is necessary. high strength steels, however, may have mechanical properties that are significantly different from those of the conventional steels. The application of high-strength steels to building structures should be reviewed as to whether inelastic behavior equivalent to that of conventional steels can be attained or not. This study researched the structural behavior of high strength circular tubes compression and under flexure. Three column tests and three flexural tests were carried out. The suitability of existing design formulae(KBC 2009) and the structural behavior were investigated through these columns and beams with various types.

• Structural Engineering and Mechanics
• /
• v.19 no.6
• /
• pp.653-677
• /
• 2005

Concrete filled steel tubular columns (CFT) are widely used in civil engineering works, especially in large scale of works because of high strength, deformation, toughness and so on. On the other hand, as a kind of strengthening measure for seriously damaged reinforced concrete piers of viaduct in Hansin-Awaji earthquake of Japan in 1995, reinforced concrete piers were wrapped with steel plate. Then, a new kind of structure appeared, that is, reinforced concrete filled steel tubular column (RCFT). In this paper, compression test and bending-shearing test on RCFT are carried out. The main parameters of experiments are (1) strength of concrete, (2) steel tube with or without rib, (3) width-thickness ratio and (4) arrangement of reinforcing bars. According to the experimental results, the effect of parameters on mechanical characteristics of RCFT is analyzed clearly. At the same time, strength evaluation formula for RCFT column is proposed and tested by experimental results and existed recommendations (AIJ 1997). The strength calculated by the proposal formula is in good agreement with test result. As a result, the proposed evaluation formula can evaluate the strength of RCFT column properly.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.226-231
• /
• 2004

Press fitting method for joining of a hybrid tube and steel ring with small teeth for automotive aluminum/composite hybrid propeller shaft was devised to improve reliability and to reduce manufacturing cost, compared to other joining methods such as an adhesively bonded joint, bolted joint or welded joint. To obtain high strength of the press fit joint, an optimal design method for the teeth was devised with respect to number and shape of the steel teeth. Torsional static, fatigue tests and finite element analysis of the press fit joint were performed with respect to experimental variables. The developed optimal design method predicted well the static torque capability and failure mode of the press fit joint. Also, it provided design guide line of press fit joint for improving torsional static and fatigue characteristics.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.10
• /
• pp.4024-4030
• /
• 2010

Axial load tests and cyclic load tests for FRP reinforced rectangular CFT columns were carried out The main parameters were width-thickness ratio of a steel tubeand FRP layer numbers for the axial load tests and were concrete strength and FRP layer numbers for cyclic load tests. The maximum strength and ductility capacity were compared between the current CFT columns and the FRP reinforced CFT columns. Finally, the axial design formulas were presented for the FRP reinforced CFT columns.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.787-792
• /
• 2002

The voided slab have many advantages, light weight, high load-distribution capacity, low cost and beautiful appearance, etc. But they have also many cracks due to difficulties in designs and construction, analysis, shrinkage, installation and rising force of voided tube. This paper presents the retrofit effects with steel plate(SP)/carbon fiber sheet(CFS) of RC voided slab. As a results of this study, it proved that the strip pattern has to be profitable than full-face pattern in performance such as crack, ultimate loads, stiffness. Retrofit length has many influence on retrofit effects, as the length increases, performance and stability of end blocks higher. Also, it proved that the retrofit on full-section has to be profitable than voided-section in performance, and the overlay length of CFS is desirable to extent approximately and welding(V-cut) has to be efficient than anchors in SP connection. But the kinds of end block and anchor has not influence on retrofit effects.