Abstract
To further investigate mechanical properties of the UHPC-filled anchorage system for CFRP cables after fire, pullout tests were conducted on the CFRP cable-UHPC interface after cooling from elevated temperature exposure, considering initial pullout load ratio R. Effects of treatment temperature Tt, R and effective bond length Le on the residual bond-slip behavior of bonding interface after thermo-mechanical coupling were identified. The recovery laws of residual bonding properties of the bonding interface after thermo-mechanical coupling were also quantified. Finally, practical formulas were proposed to determine the residual average bond strength τu-A and recovery proportions of τu-A and the effective shear stiffness KA for the bonding interface after thermo-mechanical coupling. Results demonstrated that slip failure was the primary failure mode at bonding interfaces in all pullout specimens after thermo-mechanical coupling. τu-A and KA decreased by 31.95~32.57% and 21.68~28.78% as Tt increased from 25°C (ambient temperature) to 210°C (the glass transition temperature of resin matrix), respectively. Compared with specimens without initial pullout load after cooling from elevated temperature exposure, those with R ranging from 0.2 to 0.6 and Le of (5~15)d after exposure to 100°C showed further reductions of 4.35~15.43% in τu-A and 9.78~31.13% in KA. The recovery proportions of τu-A and KA increased with increasing Tt in the range of 25~210°C, and decreased with R varying from 0 to 0.6. Practical formulas proposed in this study can predict τu-A and the recovery laws of bonding properties with good accuracy.
Key Words
CFRP cable-UHPC interface; pullout test after thermo-mechanical coupling; recovery law;
residual bonding performance
Address
Zhengwen Jiang: 1)Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan University, Changsha, 410082, China
2) Key Laboratory for Damage Diagnosis of Engineering Structures of Hunan Province, College of Civil
Engineering, Hunan University, Changsha, 410082, China
Xilong Zhao:Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan
University, Changsha, 410082, China
Hao Chen:Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan
University, Changsha, 410082, China
Zhi Fang:Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan
University, Changsha, 410082, China
Quanhao Li:Key Laboratory for Wind and Bridge Engineering of Hunan Province, College of Civil Engineering, Hunan
University, Changsha, 410082, China
Abstract
This study introduces a novel seismic energy dissipation device, the steel Radially Perforated Plate Damper
(RPPD), designed to act as a ductile fuse and enhance the seismic resilience of steel Moment Resisting Frames (MRFs).
The RPPDs are designed to promote yielding in the radial strips, thus enabling the primary structural components to
remain elastic during seismic events, and facilitating post-event recoverability. Analytical models have been developed
to predict the elastic stiffness and yield resistance of RPPDs. The accuracy of the proposed equations has been verified
through refined nonlinear finite element simulations, demonstrating satisfactory agreement with discrepancies of about
10%. The performed analyses showed that the RPPDs exhibit a stable hysteretic behavior without strength degradation
or pinching effects, even at large drift angles of up to 0.07 radians. Parametric studies highlighted the significant
influence of the strip width on the energy dissipation capacity and overall performance. The thickness and length
parameters have less effect on cyclic performance compared to the previously considered parameter. Furthermore, the
parametric study highlights the influence of key parameters that govern the critical balance between ductility and
stiffness, a factor that must be carefully considered in design applications. The study demonstrates that the geometry of
the dampers can be tailored to achieve specific performance characteristics.
Key Words
finite element analysis; hysteretic behavior; radially perforated plate damper (RPPD); seismic
energy dissipation; steel moment frames
Address
Mohammad Almohammad-Albakkar:Department of Civil Engineering, Alfurat University, Deir ez-Zor, Syria
Zaid A. Al-Sadoon:Department of Civil & Environmental Engineering, College of Engineering,
University of Sharjah, P.O. Box. 27272, United Arab Emirates
Moussa Leblouba:Department of Civil & Environmental Engineering, College of Engineering,
University of Sharjah, P.O. Box. 27272, United Arab Emirates
Mario D' Aniello:Department of Structures for Engineering and Architecture, University of Naples "Federico ll",
Via Forno Vecchio 36, 80134 Naples, Italy
Abstract
The increase application of adhesive bonded joints in shipbuilding requires the development of accurate
and suitable methodologies to measure the fracture properties of these connections. In this work, the Tapered Double Cantilever Beam (TDCB) test was used to perform fracture characterization under mode I loading of ductile adhesive
bonded joints considering naval steel adherends. Experimental fracture tests were carried out under quasi-static
loading. The load-displacement curves were registered and used to obtain the Resistance-curves after post-processing
analysis. In this context, two data reduction methods not depending on crack length monitoring during the fracture
tests were proposed. A finite element analysis including cohesive zone modelling was performed aiming to validate
the followed procedure. It was concluded that the TDCB test is a good option regarding fracture characterization of
steel bonded joints, namely when ductile adhesives are used.
Key Words
adhesive joint; fracture characterization; naval steel; shipbuilding; TDCB
Address
Ana Álvarez:Universidade da Coruñ a, Campus Industrial de Ferrol, Departamento Ingeniería Naval e Industrial, Escola
Politécnica de Enxeñaría de Ferrol, CITENI, Ferrol, 15403, A Coruña, Spain
Marcelo F.S.F. de Moura:Faculdade de Engenharia da Universidade do Porto, Departamento de Engenharia Mecânica, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
Nuno Dourado:CMEMS-UMinho, Departamento de Engenharia Mecânica, Universidade do Minho, Campus de Azurém,
4804-533 Guimarães, Portugal
Abstract
This study investigated the performance of a novel energy dissipation device, namely Oval plate damper
(OPD), and its effectiveness in structural seismic performance enhancement. The proposed OPD and corresponding
brace system were designed to effectively enhance the member deformation capacity to resolve the insufficient
deformability in traditional braces, and simultaneously upgrade the energy dissipation capability. Cyclic loading tests
on OPD-Braces with various energy dissipation plate geometries and frames with and without the proposed OPD
Braces, respectively, were conducted. It was found from the brace test results that adequate strength, stiffness,
equivalent viscous damping and significant energy dissipation were simultaneously achieved in OPD-Braces. Six
yielding zones were successfully developed in the OPD to effectively dissipate energy. The maximum equivalent
viscous damping in the OPD-Braces was approximately 36.18% to 39.71%, respectively. Results from frame cyclic
loading tests demonstrated that significant enhancements in strength, elastic stiffness and energy dissipation were
achieved in frames equipped with the proposed OPD-Braces, up to 1.93, 2.38 and 2.04 times, respectively, those of
the special moment frame. These results justified the applicability of the proposed OPD-Brace to structural seismic
performance upgrading.
Key Words
energy dissipation; multi-yielding; OPD-Brace; oval plate damper; seismic performance
Address
Trung T. Dang:Dept. of Civil Engineering, National Central University, Chung-Li, Taoyuan 32054, Taiwan
Hsieh-Lung Hsu:Dept. of Civil Engineering, National Central University, Chung-Li, Taoyuan 32054, Taiwan
Indra R. Saputro:1)Dept. of Civil Engineering, National Central University, Chung-Li, Taoyuan 32054, Taiwan
2)Dept. of Civil Engineering, Universitas Jenderal Soedirman, Purwokerto, Central Java 53122, Indonesia
Alfin Suprayugo:1)Dept. of Civil Engineering, National Central University, Chung-Li, Taoyuan 32054, Taiwan
2)Dept. of Civil Engineering, Universitas Muhammadiyah Malang, Malang, East Java 65144, Indonesia
I. P. Ellsa Sarassantika:Dept. of Civil Engineering, Universitas Warmadewa, Denpasar, Bali 80239, Indonesia
Abstract
This paper presents shear behaviour of hybrid high-strength steel (HSS) girders subjected to three-point
bending. Finite element (FE) models were developed and validated against existing experimental results for welded
homogenous and hybrid girders. The validated FE models were then employed for parametric studies on three
different HSS materials with varying nominal yield strengths: 460 MPa, 690 MPa, and 960 MPa. The FE analysis
results were presented in the form of shear capacity and observed failure modes. As anticipated, web thickness has a
more significant positive impact on shear capacity compared to flange thickness. However, a noticeable
improvement in ductility with increasing flange thickness was observed, in contrast to web thickness increases. Three
typical failure modes were observed in HSS plate girders: shear dominant, bending dominant, and combined shear
and bending modes. Additionally, the applicability of design equations in European Standard (EN 1993-1-5), Direct
Strength Method (DSM), and modified DSM versions were assessed through reliability analysis, indicating that these
equations are not suitable for designing HSS plate girders under shear. Consequently, modified design equations
based on EN 1993-1-5 and DSM for rigid and non-rigid end supports were proposed, offering conservative, lower
variance and reliable predictions for hybrid HSS plate girders.
Key Words
direct strength method; hybrid HSS girders; shear capacity; steel I-beam; three-points bending
Address
Keshav Saini:Department of Civil and Infrastructure Engineering, Indian Institute of Technology Jodhpur, India, Jodhpur - 342030
Ricky Lalthazuala:Department of Civil Engineering, National Institute of Technology Mizoram, India, Mizoram – 796012
Tekcham G. Singh:Department of Civil and Infrastructure Engineering, Indian Institute of Technology Jodhpur, India, Jodhpur - 342030
Abstract
This paper introduces a practical method for multi-material topology optimization of continuum structures
subjected to harmonic load excitation, encompassing a broad range of materials from compressible to incompressible.
The approach leverages a specialized polytopal composite finite element (PCE) framework capable of addressing
diverse material behaviors, effectively mitigating volumetric locking issues commonly observed in nearly
incompressible materials. Furthermore, a generalized harmonic load model, incorporating damping effects, is
employed to deliver a comprehensive solution for multi-material optimization. This innovative method accommodates
various elemental geometries, such as triangles, quadrilaterals, and polygons, across both compressible and nearly
incompressible material regimes. The paper provides rigorous mathematical formulations for optimizing the topology
of multi-material structures and demonstrates the method's efficiency and accuracy through a series of numerical
examples. The proposed approach is validated by comparing optimized designs with those derived from traditional
methods, highlighting its advantages. Additionally, the influence of varying excitation frequencies, damping
coefficients, and force amplitudes on the optimized results is thoroughly examined, underscoring the critical
importance of considering such factors in the design of resonant structures.
Key Words
harmonic force excitation; incompressible materials; multiple materials; polygonal discretization;
topology optimization
Address
Hieu P. Ban:Department of Architectural Engineering, Sejong University, Seoul 05006, Korea
Thanh T. Banh:Research Institute of Industrial Technology, Pusan National University, Busan 46241, Korea
Soomi Shin:Research Institute of Industrial Technology, Pusan National University, Busan 46241, Korea
Dongkyu Lee:Department of Architectural Engineering, Sejong University, Seoul 05006, Korea
