Abstract
This study investigates the overstrength factor (Ω) of an innovative -shaped metallic shear damper designed for enhancing seismic resilience in concentrically braced frames (CBFs). To evaluate the influence of geometric variables-including web/flange thickness, damper height, and slenderness ratios (λw, λf, λh) -a parametric study was conducted using 100 finite element models validated against experimental tests. The results demonstrate that all considered I-shaped dampers exhibit Ω values exceeding 1.5, surpassing the AISC recommendations for shear links. t was found that while increasing web plate thickness significantly improves ultimate strength (up to 2.35 times, it tends to reduce Ω. Conversely, increasing flange thickness enhances both ultimate strength and Ω, challenging current guidelines that often neglect flange contributions. Specifically, within the flange slenderness range of 10 ≤ λf ≤15 , the reduction rate of structural parameters is most significant. To ensure balanced seismic performance and economic efficiency, this study proposes designing dampers with a web slenderness ratio of λw ≤ 33 and a strength ratio of ψ > 5.0. These findings offer quantitative insights for refining design guidelines to accurately reflect the damper's overstrength capacity.
Key Words
capacity; -shaped; metallic damper; overstrength; slenderness
Address
Seong-Hoon Jeong:Department of Architectural Eng, Inha University, 100 Inha-ro Michuhol-gu, Incheon 22212, Republic of Korea
Ali Ghamari:Department of Civil Engineering, Il.c., Islamic Azad University, Ilam, Iran
Majid M. Rad:Department of Structural and Geotechnical Engineering, Széchenyi István University, 9026 Győr, Hungary
Abstract
This paper introduces simplified mechanics-based modeling approaches to comprehend the shear
behavior of steel beams with web openings. The behavior of the web posts was numerically investigated,
encompassing elastic buckling, inelastic buckling, and post-buckling behavior. Model outcomes indicated that web
openings amplify shear stress in the web posts, leading to premature shear buckling. Upon validating the approaches
against test data, the shear resistance of the web posts with openings was quantified considering pre- and post
buckling behavior, which are linked to the geometric properties of the beam. A practical design methodology is
proposed to ensure flexure failure while preventing shear failure of web posts with sequential openings.
Key Words
finite difference method; inelastic buckling; steel beam; tension field action; web opening; web
post
Address
Ju-Hyung Kim:Department of Architecture, Ajou University,
206, World cup-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, Republic of Korea
Young Hak Lee:Department of Architectural Engineering, Kyung-Hee University,
1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea
Jang-Woon Baek:Department of Architectural Engineering, Kyung-Hee University,
1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea
Dae-Jin Kim:Department of Architectural Engineering, Kyung-Hee University,
1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea
Abstract
Cold-formed steel (CFS) members are highly susceptible to instability phenomena (buckling), given the
high width-to-thickness ratio of their elements, which can affect the members resistant capacity. The objective of this
research is to verify the applicability of the currently codified Direct Strength Method (DSM) design curves on
predicting failure moments of cold-formed steel hat-section beams under non-uniform bending about the major and
minor-axis, regarding the risks of distortional failure. Using a numerical finite element shell model, the failure
moments were obtained for 960 beams, combining: (i) 12 geometries, (ii) five moment gradients, (iii) two bending
axes and (iv) eight distortional slenderness values. The results indicate that the currently codified DSM distortional
design curves are inadequate to estimate failure moments of members with moderate-to-high distortional slenderness.
In order to estimate more adequate failure moments and restrict the number of unsafe predictions, adjustments in the
design curve parameters were proposed.
Abstract
To investigate the axial compression behavior of cruciform steel reinforced concrete composite stub
columns with high-strength concrete and Q690 steel, six specimens were tested under axial compression loading and
analyzed by using finite element analysis. The research parameters included stirrup spacing, stirrup type, and steel fiber
content in concrete. Results show that reducing the stirrup spacing leads to minor improvement in the bearing capacity
of the steel fiber-reinforced composite stub columns. Similarly, the configuration of multiple stirrups may also have a
negligible effect on the bearing capacity of the composite columns. However, reducing the stirrup spacing and
configuring multiple stirrups can significantly improve the ductility of the specimens. In contrast, adding 2% steel fibers
can remarkably improve the bearing capacity and ductility of the composite columns. Subsequently, the axial bearing
capacity of the specimens was predicted using the current design codes, and it was found that the predictions were all
conservative. Finally, finite element analysis was conducted to further study the axial compression behavior of the
tested composite columns.
Address
Zhengbo He:1)Sanya Science and Education Innovation Park of Wuhan University of Technology,
Sanya, Hainan,572025, China
2)School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China
Ahmed Samir Elsemeen:1)Sanya Science and Education Innovation Park of Wuhan University of Technology,
Sanya, Hainan,572025, China
2)School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China
Tao Li:1)Sanya Science and Education Innovation Park of Wuhan University of Technology,
Sanya, Hainan,572025, China
2)School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China
Ming-Shan Zhao:Singapore Institute of Technology, Singapore 828608, Singapore
Sing-Ping Chiew:Singapore Institute of Technology, Singapore 828608, Singapore
Abstract
In a vibration control structure, a damper is a key device that dissipates energy generated in the structure.
Recently, dampers with new materials and structural shapes have been developed, but friction and steel dampers,
which have simple energy dissipation mechanisms and are highly cost-effective, are widely used in practice. In this
study, a numerical investigation study was conducted on a yield friction damper combining a friction damper and a
steel damper using existing materials. The yield friction dampers are designed in a modular form and induce friction
by applying friction bolts. For numerical investigation, the bolt load and strut pitch are basically set as parameters,
and finite element analysis is performed on the conventional slit damper and yield friction damper. As a result of the
analysis, it was confirmed that the yield friction damper had improved maximum force and energy dissipation
performance compared to the existing slit damper.
Key Words
damper; energy dissipation; finite element analysis; friction; yielding
Address
Heon Woo Lee:Department of Civil and Environmental Engineering, Incheon National University,
Incheon 22012, Republic of Korea
Young Chan Kim:1)Industry-Academic Cooperation Foundation, Incheon National University, Incheon 22012, Republic of Korea
2)Incheon Disaster Prevention Research Center, Incheon National University, Incheon 22012, Republic of Korea
Han Min Cho:Department of Structural Engineering Research, Korea Institute of Civil Engineering and Building Technology, Goyang 10223, Republic of Korea
Jong Wan Hu:Department of Civil and Environmental Engineering, Incheon National University,
Incheon 22012, Republic of Korea
Abstract
Compared to traditional cold-formed thin-walled steel (CFS) opening section, CFS beams with built-up
double-limb ∑-shaped sections (CFSBDS) exhibit significantly greater torsional rigidity. The addition of web and
flange stiffeners in CFS members not only increases the section moment of inertia but also mitigates web buckling
issues. Consequently, incorporating stiffeners effectively enhances the ultimate bending moment capacity of bending
members. The flexural behavior of CFSBDS was investigated using numerical analysis methods. Two types of built
up section beams were considered: CFSBDS flanges with and without stiffeners. Finite element (FE) models were
developed using ABAQUS software, and their accuracy was validated by comparing them with experimental results
reported in the literature, considering failure modes, moment capacities, and moment vs. deflection curves. To
explore various combinations of web stiffener depth, flange stiffener width, and thickness of the built-up closed
section, a numerical parametric study was conducted using the validated FE models. The FE analysis results indicate
that increasing the ratio of web stiffener depth-to-beam width from 0 to 0.5 leads to a 27% increase in ultimate
strength. Additionally, raising the ratio of flange stiffener depth-to-beam width from 0 to 0.33 results in a 45%
enhancement in ultimate strength. There is no significant variation observed in the flexural capacity of built-up closed
section beams due to changes in the width of flange stiffeners. The suitability and effectiveness of design methods
outlined in Chinese GB/T50018-2025 and AISI S100-16 for calculating bending moment values of CFSBDS were
evaluated, revealing that these prediction methods tend to be conservative compared to FE analysis.
Key Words
built-up beam with ∑-shaped section; cold-formed steel; design method; flexural behavior;
numerical analysis
Address
Shaofeng Nie:School of Civil Engineering, Chang'an University, Xi'an, 710061, China
Bo Ran:School of Civil Engineering, Chang'an University, Xi'an, 710061, China
Jun Zhu:School of Civil Engineering, Chang'an University, Xi'an, 710061, China
Qingxu Yin: School of Civil Engineering, Chang'an University, Xi'an, 710061, China
Xin Jiang:School of Civil Engineering, Chang'an University, Xi'an, 710061, China
Weijie Wu:Centerint Group Co. Ltd., 10, Yongchang East 4th Road, Beijing, China
Yang Zhang:School of Civil Engineering, Chang'an University, Xi'an, 710061, China
