Abstract
Bridges traversing active faults in aggressive environments (such as coastal or reservoir regions) face the
coupled risks of chloride-induced corrosion and fault-crossing seismic excitations. The failure mechanisms
governing continuous rigid frame bridges (CRFBs) under such coupled degradation-seismic conditions remain
poorly understood. This study develops an integrated analytical framework comprising: (i) time-dependent
deterioration models accounting for chloride-induced reinforcement section loss, yield-strength reduction, and
concrete cover softening; and (ii) a refined 3D nonlinear finite element model (FEM) incorporating fiber beam
column elements, a soil-structure interaction system (SSIS), bearings, and pounding effects. (iii) Synthetic fault
crossing ground motions are generated by superimposing low-frequency fling-step pulses onto spectrum-matched
high-frequency records. These synthetic motions are then applied to the bridge model via multi-support excitation.
Comparative analyses demonstrate that fault-crossing motions shift the structural response from an inertia-dominated
amplification mode to a quasi-static forced displacement mode. This mode shift imposes significantly larger and
more asymmetric kinematic demands compared to standard near-fault scenarios. Structural responses exhibit a
nonlinear dependence on permanent ground rupture displacement (PGRD), typically plateauing at an observed peak
of 0. 6 m for the examined cases. This phenomenon is attributed to a force-limiting mechanism: the yielding of
foundation soil and the premature plastic hinging of corroded piers restrict the inertial force transmission to the
superstructure. Furthermore, the fault-crossing angle (FCA) governs the demand distribution, exhibiting an
Key Words
continuous rigid frame bridge; corrosion-induced degradation; fault-crossing ground motion;
frequency decoupling; soil-structure interaction system
Address
Hongyu Jia:State Key Laboratory of Bridge Intelligent and Green Construction, Southwest Jiaotong University, Chengdu, 611756, Sichuan, China
Jiahao Hou:School of Civil Engineering, Southwest Jiaotong University, Chengdu, 610031, China
Hao Bai:Sichuan Expressway Construction & Development Group Co., Ltd., Chengdu, 610041, China
Zhi Xu:Shudao Investment Group Co., Ltd., Chengdu, 610094, China
Kang Jia:Sichuan Chengdu Construction Engineering Group Co., Ltd., Chengdu 610000, Sichuan, China
Shixiong Zheng:1)State Key Laboratory of Bridge Intelligent and Green Construction, Southwest Jiaotong University, Chengdu, 611756, Sichuan, China
2)School of Civil Engineering, Southwest Jiaotong University, Chengdu, 610031, China
Abstract
The connection between modules is critical to ensuring the overall structural safety of modular steel
buildings. However, many existing modular systems require openings to be made in the column walls, which
adversely affect the global structural performance. Additionally, existing non-opening connection systems generally
exhibit relatively low stiffness and load-bearing capacity. To address these issues, this study proposes a novel
connection, screwed sleeve connection (SSC) for modular steel structures, which connects modules inside the
columns and preserves the integrity of the modules. Four sets of symmetric connections were tested to investigate its
shear performance, considering the influences of sleeve diameter, sleeve thickness and different connection
configurations. Test results show that connection failure is governed by the screwed sleeve (SS), progressing through
four stages: shearing of the locating rod (LR), yielding of the sleeve, buckling of the sleeve and strengthening of the
sleeve. A finite element model was developed and validated against the experimental results, followed by parametric
analyses. Subsequent parametric analyses revealed that the sleeves diameter and thickness are key factors affecting
the shear performance. A 40% increase in the sleeve-to-column thickness ratio led to a 31.97% increase in the shear
strength, while a 24% increase in the sleeve diameter-to-column cavity net width ratio led to a 27.84% increase. A
simplified model is proposed to predict the shear strength of SSC, showing satisfactory accuracy for practical
engineering applications.
Address
Xinyi Song:JiangSu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of
Mining and Technology, Xuzhou 221116, China
Xiaoyu Yan:JiangSu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of
Mining and Technology, Xuzhou 221116, China
Zhanguo Ma:JiangSu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of
Mining and Technology, Xuzhou 221116, China
Yidu Bu:School of Sustainability, Civil and Environmental Engineering, University of Surrey,
Surrey GU2 7XH, United Kingdom
Pinhan We:1)JiangSu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of
Mining and Technology, Xuzhou 221116, China
2)Suzhou industrial Park high-end manufacturing and international trade zone, Suzhou 215024, China
Ying Wang:1)1JiangSu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of
Mining and Technology, Xuzhou 221116, China
2)School of Civil Engineering, Xinjiang Institute of Engineering, Urumqi, 830023, China
Hongfei Chang:1)1JiangSu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of
Mining and Technology, Xuzhou 221116, China
2)School of Civil Engineering, Xinjiang Institute of Engineering, Urumqi, 830023, China
Abstract
S32001 duplex stainless steel has recently been developed as a structural material in building
engineering, offering an attractive balance of high mechanical strength, cost efficiency, and excellent corrosion
resistance. Nevertheless, its low-cycle fatigue (LCF) behaviour has not been adequately investigated, which limits its
wider engineering application. In this study, strain-controlled LCF tests were conducted on S32001 stainless steel
under two strain ratios which comprised -1 and 0. For each strain ratio, seven strain amplitudes were employed
which included 1.0%, 1.25%, 1.5%, 1.75%, 2.0%, 2.25% and 2.5%. The experimental program focused on cyclic
deformation characteristics, stress-strain response, and fracture morphology. Fatigue life was further assessed using
the Basquin-Coffin-Manson framework and a strain energy-based model. The results revealed that S32001 stainless
steel exhibits a clear cyclic hardening-softening sequence and possesses fatigue resistance superior to that of
conventional structural steels. Life prediction analyses indicated that the strain-life approach provides effective fatigue
life estimations, with the Basquin-Coffin-Manson model showing better agreement with the experimental data than
the strain energy model.
Key Words
Basquin-Coffin-Manson model; life prediction; low-cycle fatigue behaviour; S32001 duplex
stainless steel
Address
Peng Dai:Department of Civil Engineering, Tsinghua University, China
Yuanqing Wang:General Affairs Office, Southeast University, China
Tianxiong Zhang:General Affairs Office, Southeast University, China
Mingze Wu:General Affairs Office, Southeast University, China
Yecheng Dai:Department of Civil Engineering, Tsinghua University, China
Abstract
This study examines the axial buckling behaviour of perforated cold-formed steel (CFS) equal-angle
face-to-face built-up columns strengthened with longitudinal stiffeners through experimental testing, finite element
analysis, and theoretical evaluation. Circular perforations introduced for service integration reduce sectional stiffness
and increase susceptibility to local, distortional, and global buckling. Experimental tests were conducted on 1.2 mm
thick, 900 mm long built-up CFS angle columns with stiffener spacing of 50, 100, and 150 mm under pinned–pinned
axial compression, and the resulting load–deflection responses and failure modes were used to validate nonlinear
finite element (FE) models developed in ABAQUS incorporating geometric imperfections and material nonlinearity,
which were subsequently extended to parametric studies covering section thicknesses of 1.2–1.6 mm and member
lengths of 900–1600 mm. Results indicate that decreasing stiffener spacing significantly enhances buckling
resistance, with 50 mm spacing increasing axial capacity by up to 45 % compared with unstiffened columns.
Stiffener spacing, section thickness, and column slenderness were found to govern buckling mode transitions. DSM
based calculations were evaluated and show reasonable consistency with the experimental and numerical results for
perforated and stiffened members. The findings provide quantitative design guidance for perforated CFS built-up
angle columns in accordance with AISI S100 and IS 801.
Key Words
ABAQUS; buckling modes; cold formed steel; Finite Element Analysis and Direct Strength
Method (DSM); perforated equal angle section; stiffener spacing
Address
Priyanka R. Bhivgade:Veermata Jijabai Technology Institute, Structural Engineering Department, Mumbai, India
Keshav K. Sangle:Veermata Jijabai Technology Institute, Structural Engineering Department, Mumbai, India
Umesh A. Maske:Veermata Jijabai Technology Institute, Structural Engineering Department, Mumbai, India
Vikram Singh:Veermata Jijabai Technology Institute, Structural Engineering Department, Mumbai, India
Abstract
Earthquakes have historically caused significant impacts on human societies and the built environment,
emphasizing the need for proactive disaster preparedness. Seismic retrofitting is a key strategy for enhancing
structural resilience, particularly for existing buildings that do not meet modern seismic standards. This study
examines the effectiveness of retrofitting steel ordinary braced frames (OBFs) with buckling-restrained braces
(BRBs). Three prototype OBF buildings of varying heights (4, 6, and 10-story) are designed according to an outdated
code and retrofitted by replacing conventional braces with BRBs. A detailed finite element (FE) model is developed
and validated against experimental data, then used to conduct a comprehensive seismic resilience assessment,
including fragility analysis and loss estimation in terms of repair cost, repair time, and debris generation. Incremental
dynamic analysis (IDA) is performed on unretrofitted and retrofitted buildings using eleven scaled ground motions,
with simulations carried out up to collapse. Fragility curves quantify improvements in peak ground acceleration and
base shear due to BRB retrofitting. Results show that BRBs substantially enhance resilience, reducing interstory
drifts by 45%, repair cost by 47%, repair time by 44%, and debris by 57%. These findings confirm the effectiveness
of BRBs, especially for low- and mid-rise buildings in seismically active regions.
Abstract
Concrete-filled steel tubes (CFSTs) are composite systems applied to earthquake-resistant structures that
enhance structural performance such as strength and ductility by combining the confinement effect of steel tubes with
the compressive capacity of concrete. However, steel, the primary component of CFST, is susceptible to corrosion
when exposed to the external environment over extended periods, which can lead to degradation of structural
performance and even structural collapse. To address issues and enhancing the performance of CFST columns, this
study conducted a numerical analysis on concrete-filled CFRP tube (CFCT) and concrete-filled hybrid CFRP tube
(CFHT) column structures, which replace steel with CFRP. In addition, to evaluate the seismic performance of CFCT
and CFHT columns, the results of the numerical analysis were statistically analyzed for roof displacement, inter-story
drift ratio, residual inter-story drift ratio, column stress, energy dissipation amount and permanent deformation.
Consequently, the CFCT and CFHT column structures exhibited superior seismic performance in evaluation results.
Address
Young Chan Kim:1)Department of Civil and Environmental Engineering, Incheon National University,
Incheon 22012, Republic of Korea
2)Industry-Academic Cooperation Foundation, Incheon National University, Incheon 22012, Republic of Korea
3)Incheon Disaster Prevention Research Center, Incheon National University, Incheon 22012, Republic of Korea
Seyed Javad Mortazavi:Incheon Disaster Prevention Research Center, Incheon National University,
Incheon 22012, Republic of Korea
Jong Wan Hu:1)Department of Civil and Environmental Engineering, Incheon National University,
Incheon 22012, Republic of Korea
2)Incheon Disaster Prevention Research Center, Incheon National University,
Incheon 22012, Republic of Korea
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