Abstract
This study proposed an innovative chevron-braced steel frame system with replaceable energy
dissipation connections based on the design concept of performance-based seismic design and replaceable energy
dissipated elements. The connections incorporated two double U-shaped metal dampers as its core functional
elements with one on each side. It connected to the side gusset plate on one side and to a gusset plate attached to the
column on the other side with high-strength bolts. Through the optimization of the cross-section of energy-dissipation
components, beams and columns. It is ensured that under seismic excitation, plastic damage is concentrated in the
energy-dissipation connection, while the main beam and column components remain basically elastic or in a slightly
damaged state. The connections can be conveniently disassembled and replaced after an earthquake, thereby
improving construction efficiency. To investigate the seismic performance and post-earthquake repair performance of
the frame equipped with the proposed connections, quasi-static tests were conducted on a 1/2 scale single-story,
single-span substructure specimen and a repaired specimen. The strength, hysteresis, and skeleton curves of the
specimens were studied to compare the difference between initial and repaired specimens. Notably, the initial loading
phase was completed when the inter-story drift ratio reached 0.83%, whereas the residual inter-story drift ratio of the
structure was 0.28% After replacing the connections, the mechanical properties of the structure were similar to the
original structure. In addition, three-dimensional finite element models were established in ANSYS. After the
correctness of the analysis model was verified by the test results, parametric analysis was performed. The effects of
the connections, floor, and metal damper size on the structural performance were investigated. The numerical
simulation revealed that, compared with the simple chevron-braced steel frame, the frame with the connections can
prevent the brace from buckling. The floor effect promoted the safety of steel beams and should not be ignored. This
study recommends that the stiffness ratio of the energy-dissipation frame system to the energy-dissipation
connections should be maintained between 2.73 and 3.57 in the design.
Address
Hongwei Ma:School of Civil Engineering and Transportation, South China University of Technology,
Guangzhou 510641, China
Yixian Weng:School of Civil Engineering and Transportation, South China University of Technology,
Guangzhou 510641, China
Wei Xiong:1)Guangzhou Construction Co., Ltd., Guangzhou 510030, China
2)China Guangzhou International Economic and Technical Co., Ltd., Guangzhou 510180, China
Jing Jiang:Zhejiang Ocean University, Zhoushan 316022, China
Jiaxin Xu:Natural Resources and Planning Bureau of Danzhou City, Danzhou 571700, China
Ming Li:School of Civil Engineering and Transportation, South China University of Technology,
Guangzhou 510641, China
Abstract
The beam-column connection approach significantly impacts the seismic performance of frame
structures. This report proposes a novel resilient prefabricated hinged beam-column joint equipped with rotation
control and energy-dissipating load-bearing capabilities (RCEL-RPHJ). The design facilitates off-site prefabrication
and on-site assembly, encompassing a prefabricated column with cantilevered section, a prefabricated beam, and a
hinged core area with rotation control. Initially, the paper details the configuration, assembly process, and working
mechanism of the RCEL-RPHJ. Subsequently, a numerical simulation analysis of the RCEL-RPHJ is conducted
following the validation of the finite element modeling strategy. And taking into account 10 different factors, a
parametric analysis was performed on a total of 18 finite element models of the RCEL-RPHJ. Findings reveal that
the secondary peak load of the RCEL-RPHJ exceeds initial peak load by 7%. After loading, plastic deformation is
concentrated in the cover plates, lateral plates, and limiting bolts of the hinged core area, with no significant inelastic
deformation in other main components. For optimal rotational control and energy dissipation, the specification of
limiting bolts should be M20 or larger, and in configurations with a cantilever, the distance between the hinge core
and the column end should be less than 545 mm.
Abstract
While functionally graded materials (FGMs) offer significant potential for optimizing structural elements,
thin-walled members featuring non-uniform material distributions encounter complex buckling modes due to inherent
cross-sectional asymmetry. Addressing the challenge of efficiently modeling these behaviors, this paper introduces a
computational framework combining advanced cross-sectional analysis with a large deflection beam-column
formulation. First, a novel "functionally graded segments method" is developed for thin-walled open sections with
FGMs graded along the thickness direction. This algorithm robustly computes crucial cross-sectional properties,
specifically capturing the shear center coordinates and Wagner coefficients resulting from material gradients.
Subsequently, a new warping line finite element is formulated that explicitly integrates these nonsymmetric FGM
section properties. Through a series of validation examples, the proposed method demonstrates remarkable accuracy
in predicting large-deflection responses, offering a computationally efficient alternative to complex shell or solid finite
element models. This research provides a versatile tool specifically designed for the advanced analysis and design of
open-section thin-walled members utilizing FGMs.
Key Words
functionally graded; large deflection; open-sections; section properties; thin-walled
Address
A.H.A. Abdelrahman:Department of Structural Engineering, Faculty of Engineering, Mansoura University, Egypt
Wen-Long Gao:Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University,
Hong Kong, China
Sameh Lotfy:Civil Engineering Department, Misr Higher Institute for Engineering and Technology, Egypt
Guanhua Li:Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University,
Hong Kong, China
Si-Wei Liu:Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University,
Hong Kong, China
Abstract
In this study, the vibration of a nanowire supported with elastic springs is analyzed under size effect.
Classical strain gradient theory is used to account for the impact of small size, while the vertical displacement function
is represented by two constant coefficients at the boundaries and a Fourier sine series within the domain. The effects of
perforation and short fibers are considered in the geometry and material, respectively. Stokes' transformation is applied
to force the springs at the boundaries to the desired supporting condition. High-order force boundary conditions are
used for this purpose. Unlike the natural boundary conditions typically found in most previous studies, the results
obtained in this study have a physical meaning since force conditions are used. Thanks to the coefficients matrix
obtained, the differential equation does not need to be solved again for each change in boundary conditions. The
solutions for elastic boundary conditions are compared with those in the literature, showing a perfect match. The unique
aspect of this paper is the presentation of a method that can solve both rigid and deformable boundary conditions of
perforated and short-fiber-reinforced nanowires for lateral vibration based on the classical strain gradient theory.
Abstract
To address the challenges associated with post-earthquake repair of connections between double-steel
plate composite shear walls and H-shaped steel beams, a replaceable joint is proposed that integrates a dual energy
dissipation mechanism combining friction and ductility. Two-stage energy dissipation is achieved through slip friction
at slotted holes in the web of U-shaped connectors and plastic deformation of their flanges, thereby confining plastic
damage effectively to the replaceable unit. This design fulfills the seismic objective of a "strong main structure–weak
joint" concept, facilitating rapid post-earthquake replacement and repair. A detailed ABAQUS finite element model of
a composite shear wall joint incorporating U-shaped energy dissipation devices has been established based on the
dimensions of wall-beam joints commonly used in engineering practice. The effects of the web thickness, flange
thickness, discontinuity length of the U-shaped connector, and bolt pre-tightening force on the seismic performance of
the joint are investigated. Parametric analyses reveal that increases in the web and flange thicknesses of the U-shaped
connectors, reductions in the discontinuity length, and increases in the bolt pre-tightening force enhance the load
bearing capacity. However, excessive web thickness reduces ductility, and an increase in flange thickness tends to cause
plastic damage to shift to the web. Moreover, when the preload exceeds 100 ken, frictional energy dissipation within
the joint is suppressed. Finally, based on the parametric analysis results, a semi-empirical formula is proposed for
predicting the load-bearing capacity as a function of geometric dimensions and bolt pre-tightening force, exhibiting a
maximum error within 10%.
Key Words
double-steel-plate composite shear wall; friction-ductility energy dissipation; load-bearing
capacity formula; replaceable joint; parametric analysis
Address
Jian Li:School of Civil Engineering, Qingdao University of Technology, Qingdao, 266033, China
Kai Liu:School of Civil Engineering, Qingdao University of Technology, Qingdao, 266033, China
Zhe Zhao:School of Civil Engineering, Qingdao University of Technology, Qingdao, 266033, China
Bo-Kai Chen:School of Civil Engineering, Qingdao University of Technology, Qingdao, 266033, China
Abstract
This paper presents the results of tests dealing with steel joints made using reinforced resin injection bolts
set in oversized bolt holes. Joints of this type may be applied in the cases where increased assembly tolerances are
required. A RenGel SW404 + HY2404 epoxy resin was used to inject the holes. The results have been compared
against joints with standard size bolt holes. Obtained results have been supplemented with material tests performed
on unreinforced resin. Two alternative options for reinforcing joints were considered in the cases where nonstandard
oversized circular holes were applied. An addition of silicon carbide varying in granularity was proposed as the first
option using two application modes. Reinforcement with steel bars was proposed as the second option. The tests
performed have shown, that that the standard joints and the joints with oversized holes reinforced with steel bars
behave satisfactorily when subjected to both short and long term loads. Manufacturing defects and substantial
dispersion of results were observed in joints with oversized bolt holes injected with unreinforced resin. Values of
basic strength and material parameters are given for both reinforcement options. Manufacturing issues pertaining to
execution of joints with reinforced resin are discussed as well.
