Abstract
This study addresses the lack of a comprehensive design methodology for Cold-Formed Austenitic
Stainless Steel (CFASS) Sigma columns, specifically those made from grade EN 1.4420. The structural behavior of
these columns under axial compression was investigated, with a focus on failure modes. Finite element (FE) models
were developed to simulate their performance, and the results were validated against experimental data from the
literature in terms of failure modes, strengths, and load–deformation behavior. Once validated, the FE models were
used for parametric studies, generating extensive numerical data across a range of cross-sectional dimensions (e.g.,
a/B ratios and B/H) and slenderness ratios (𝜆). Using this data, the design guidelines outlined in the AISI and
European codes were assessed. The evaluation revealed that the Direct Strength Method (DSM) in the AISI
standards generally provides reasonable estimations with some deviations toward overestimation, while the
European code exhibited underestimation and inaccuracies. To address these issues, a new procedure was developed
to predict the strengths of CFASS Sigma columns based on EC3. The proposed modifications demonstrated
improvements in accuracy and reliability, providing enhanced methods for estimating the buckling capacity of cold
formed austenitic stainless-steel Sigma-section columns.
Key Words
cold-formed austenitic stainless steel; design modification; Direct Strength Method (DSM);
finite element analysis; parametric study; sigma-section
Address
Hayat Hossany:Department of Structural Engineering, Faculty of Engineering, Tanta University, Tanta, Egypt
Nashwa M. Yossef:Department of Structural Engineering, Faculty of Engineering, Tanta University, Tanta, Egypt
M.F. Hassanein:Department of Structural Engineering, Faculty of Engineering, Tanta University, Tanta, Egypt
Abstract
Although high strength steel (HSS) with tensile strength up to 800 MPa has been used for a long time, the use of HSS flexural members in building construction is often restricted because of concerns about their low rotation capacity. This study analytically evaluates the in-plane rotation capacity of H-shaped beams made from various steel grades (325–800 MPa) under uniform and moment-gradient loading conditions. Based on tensile coupon test results for SM490, SM570, and HSA800 steels, stress-strain material models were calibrated using the Haaijer model (for mild steel with yield plateau) and Ramberg-Osgood model (for HSS without yield plateau). Moment-curvature analyses were performed to calculate rotation capacities, and the effects of key parameters were investigated: tensile-to-yield strain ratio SR (= εu/εy), yield-to-tensile strength ratio YR (= Fy/Fu), and beam geometry. Results indicate that HSA800 (SR ≈ 15, YR ≈ 0.84) achieves rotation capacity Rm < 3 under moment gradient conditions, insufficient for current design code requirements. Parametric studies demonstrate that increasing SR from 15 to 25 provides 41–45% improvement in rotation capacity, significantly more effective than geometric modifications. Web thickening (20% improvement) outperforms flange thickening (3.4% improvement) for sections under moment gradient. The findings provide guidance for HSS material development and design specification modifications.
Key Words
H-shape beam member; high-strength steel; in-plane rotation capacity; tensile–to–yield strain
ratio; yield–to–tensile strength ratio
Address
Changhee Park:Construction Team, Global Infra Technology, Samsung Electronics, 129, Samsung-ro, Yeongtong-gu,
Suwon-si 443-742, Gyeonggi-do, Republic of Korea
Jang-Woon Baek:Department of Architectural Engineering, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu,
Yongin-si 1732, Gyeonggi-do, Republic of Korea
Abstract
In this research, a new steel hysteretic damper for seismic retrofit of structures is proposed and its
performance is evaluated. The damper consists of a circular hollow column section and bidirectional flexural fuse at
each end, made of steel with reduced section, which can be installed beside existing columns of the structure to
minimize interference with architectural functions. The bidirectional fuses act as flexural hinges to dissipate the
seismic energy. The theoretical formulation and the design procedure based on plastic analysis are provided for the
proposed damper, and the results are compared with a finite element analysis (FEA) model. To validate the
applicability of the proposed damper in structural analysis, a macromodel of the damper is also developed and
calibrated by the derived theoretical formulas. The results are compared with the FEA, and the effectiveness of the
damper is further investigated by the seismic retrofit of a reinforced concrete structure. An optimization technique
based on slime mould is used to find the optimal number of dampers and their location. The performance of the
structure is evaluated in terms of interstory drift ratios, residual displacements, and dissipation of seismic energy. The
results show that the drift ratios decreased by 39.5%, residual displacements by 56 %, and energy dissipation by the
columns from 17% to 2%. The results suggest that the proposed damper can be used to effectively protect structures
from seismic loads.
Abstract
This paper aims to investigate the most suitable alternative core design using an integrated approach
involving finite element analysis (FEA) and experimental and data analytics to enhance the delamination resistance.
The core configuration has major effects on the bonding structural integrity when subjected to severe loading
conditions. Its improvement is therefore vital, although this requires an alternative method of selecting the most suitable
core design. The FEA results became the input for the data analytics. The analytical hierarchical process was used to
determine the weightage for the critical failure elements due to the high stability of the consistency checking (0.096 <
0.01). The VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) analysis was then used to select the
most suitable core design. Sensitivity and experimental analyses were performed to justify the results. The findings
showed that alternative core design A2 scored lowest on the selection measure, with 50% – 80% better delamination
resistance compared to the other designs. The statistical analysis showed that the data was reliable and 100% within
the 95% confidence boundary. This paper proposes a holistic approach that entails fusing the finite element analysis
results into a hybrid data analytical approach to enhance the durability of a sandwich panel by improvising the core
configuration.
Key Words
delamination; dimple design; holistic approach; hybrid data analytics; structural integrity
Address
M.K. Faidzi:Department of Mechanical Engineering, Faculty of Engineering, Universiti Pertahanan Nasional Malaysia,
Kem Perdana Sg. Besi, 57000 W.P Kuala Lumpur, Malaysia
S. Abdullah:Department of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment,
Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
M.F. Abdullah:1)Department of Mechanical Engineering, Faculty of Engineering, Universiti Pertahanan Nasional Malaysia,
Kem Perdana Sg. Besi, 57000 W.P Kuala Lumpur, Malaysia
2)Center for Tropicalisation, Defence Research Institute, Universiti Pertahanan Nasional Malaysia,
Kem Perdana Sg. Besi, 57000, W.P Kuala Lumpur, Malaysia
S.S.K. Singh:Department of Mechanical and Manufacturing Engineering, Faculty of Engineering and Built Environment,
Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
Abstract
This research focuses on assessing the compression behavior of the cross-shaped column in the ultra-low
energy prefabricated modular wall building system. Tests were conducted on nine groups of specimens under
compression loading, with a focus on three variables: eccentricity, column length and steel thickness. It was found that
the composite columns exhibited strong vertical bearing and deformation abilities. Each specimen demonstrated
bending failure traits. The primary reasons for the specimens' failure were the concrete being crushed, the steel buckling
and the stiffener plates experiencing bending failure. Lateral constraints were provided by the stiffener plates, which
also boosted the specimen's integrity. Through examining the test outcomes, it is evident that eccentricity significantly
influences the peak bearing capacity, decreasing with increased eccentricity. Steel and concrete operated in harmony
during the compression phase. The plane cross-section assumption is met by the middle section of the column.
Address
Xiang Zhang:1)School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China
2)School of Civil Engineering, Tianjin University, Tianjin, China
Wentao Qiao:School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China
Zhi Yang:School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China
Yahui Zhang:China Construction Sixth Engineering Division Corp. Ltd., Tianjin, China
Bing Yan:School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, China
Abstract
Shear connections that combine bolts and welds offer an effective solution for retrofitting existing
structures. While single shear joints are commonly specified in connection design, few studies have investigated their
actual behavior and load capacity. This paper investigates the load-slip response and capacity of single shear
connections combining pretensioned high-strength bolts and longitudinal fillet welds through experimental and
numerical analyses. Experimental tests were conducted under monotonic tensile loading, considering key design
variables such as weld length, weld location, and assembly sequence. A finite element model was developed and
validated to analyze these variables further. Results show that combining welds and bolts improves slip resistance and
load-resisting capacity compared to connections using only bolts or welds. Weld dimensions significantly influence
the load-slip behavior. Additionally, the slip capacity of single shear combination connections was observed to be less
than half of the capacity of the corresponding double shear combination connections. This can be attributed to the
load eccentricity and secondary bending, which delayed the development of the full weld capacity. However, these
connections are still expected to provide adequate safety factors if designed using current capacity prediction
procedure.
Key Words
fillet welds; load-slip responses; pretensioned bolts; single shear connections; combination
connections; slip critical connections
Address
Sangwook Park:School of Architecture & Building Science, Chung-Ang University, Seoul 06974, Korea
Aws Idris:School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, OK 74078, U.S.A.
Mohamed Soliman:School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, OK 74078, U.S.A.
Caleb Bennett:School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, OK 74078, U.S.A.
Bruce W. Russell:School of Civil and Environmental Engineering, Oklahoma State University, Stillwater, OK 74078, U.S.A.
