• International Journal of High-Rise Buildings
• /
• v.3 no.1
• /
• pp.21-33
• /
• 2014

The tied braced frame (TBF) system was developed to achieve uniform seismic inelastic demand along the height of multi-storey eccentrically braced steel frames. A modular tied braced frame (M-TBF) configuration has been recently proposed to reach the same objective while reducing the large axial force demand imposed on the vertical tie members connecting the link beams together in TBFs. M-TBFs may however experience variations in storey drifts at levels where the ties have been removed to form the modules. In this paper, the possibility of reducing the discontinuity in displacement response of a 16-storey M-TBF structure by introducing energy dissipating (ED) devices between the modules is examined. Two M-TBF configurations are investigated: an M-TBF with two 8-storey modules and an M-TBF with four 4-storey modules. Three types of ED devices are studied: friction dampers (FD), buckling restrained bracing (BRB) members and self-centering energy dissipative (SCED) members. The ED devices were sized such that no additional force demand was imposed on the discontinuous tie members. Nonlinear response history analysis showed that all three ED systems can be used to reduce discontinuities in storey drifts of M-TBFs. The BRB members experienced the smallest peak deformations whereas minimum residual deformations were obtained with the SCED devices.

• Earthquakes and Structures
• /
• v.6 no.5
• /
• pp.561-580
• /
• 2014

After strong earthquakes conventional frames used worldwide in multi - story steel buildings (e.g. moment resisting frames) are not well positioned according to reparability. Two innovative systems for seismic resistant steel frames incorporated with dissipative fuses were developed within the European Research Program "FUSEIS" (Vayas et al. 2013). The first, FUSEIS1, resembles a vertical Vierendeel beam and is composed of two closely spaced strong columns rigidly connected to multiple beams. In the second system, FUSEIS2, a discontinuity is introduced in the composite beams of a moment resisting frame and the dissipative devices are steel plates connecting the two parts. The FUSEIS system is able to dissipate energy by means of inelastic deformations in the fuses and combines ductility and architectural transparency with stiffness. In case of strong earthquakes damage concentrates only in the fuses which behave as self-centering systems able to return the structure to its initial undeformed shape. Repair work after such an event is limited only to replacing the fuses. Experimental and numerical investigations were performed to study the response of the fuses system. Code relevant design rules for the seismic design of frames with dissipative FUSEIS and practical recommendations on the selection of the appropriate fuses as a function of the most important parameters and member verifications have been formulated and are included in a Design Guide. This article presents the design and performance of building frames with FUSEIS 1-1 based on models calibrated on the experimental results.

• Earthquakes and Structures
• /
• v.16 no.5
• /
• pp.589-599
• /
• 2019

Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension and compression without major degradation of capacity under severe seismic ground motions. One of the weakness points of a standard buckling restrained braced frame is the low post-yield stiffness and thus large residual deformation under moderate to severe ground motions. This phenomenon can be attributed to low post-yield stiffness of core member in a BRB. This paper introduces a multi-core buckling restrained brace. The multi-core term arises from the use of more than one core component with different steel materials, including high-performance steel (HPS-70W) and stainless steel (304L) with high strain hardening properties. Nonlinear dynamic time history analyses were conducted on variety of diagonally braced frames with different heights, in order to compare the seismic performance of regular and multi-core buckling restrained braced frames. The results exhibited that the proposed multi-core buckling restrained braces reduce inter-story and especially residual drift demands in BRBFs. In addition, the results of seismic fragility analysis designated that the probability of exceedance of residual drifts in multi-core buckling restrained braced frames is significantly lower in comparison to standard BRBFs.

• The Journal of Korean Philosophical History
• /
• no.32
• /
• pp.161-183
• /
• 2011

Lee Ik(李瀷) had put emphasis on the achievements by self-regulated academic learning through doubts, and at the same time that it was all-embracing. His academic attitude had set an example among the members of Seongho school(星湖學派), and his disciples had strived to emulate his style. The greatness of Seongho(星湖)'s study had been revealed by development of Seongho school(星湖學派) right after his death. He had argued that the six strokes of I-Ching should be read having it divided into inward and outward divine signs. He had stated his view clearly that the divine signs ranging from one stroke to six strokes were not connected, same as Shao yong(邵雍)'s method, but, the three strokes of inward divine sign as well as the three strokes of outward divine signs were independent from each other. Seongho(星湖) also had raised many questions about Shifa(筮法), and Bianyao(變爻) and Zhuzi(朱子)'s Shifa(筮法), or Yixueqimeng("易學啓蒙") "Kaobianzhan("考變占")". In view of the Shifa(筮法), Seongho(星湖) had helped Dasan(茶山) to present 'Shiguafa(蓍卦法)' by proposing different divination rule from Zhuzi(朱子)'s Method of Divination by Shiyi("筮儀"). Seongho(星湖) had not professed something significantly different from Zhuzi(朱子) in his I-xue. His study on I-xue had been accomplished under his goal of achievements by self-regulated academic learning through doubts. "Shiguakao("蓍卦攷")" is also same. I-xue of Seongho(星湖) had made a great contribution to form Dasan(茶山)'s I-xue in the later years.