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CONTENTS
Volume 97, Number 1, January10 2026
 

Abstract
The panel units of frame-supported glass curtain walls are composed of glass panels, structural sealant, and supporting frames. The absence of a unified shape function makes it difficult to construct Ritz functions for solving the dynamic characteristics. This paper proposes a partitioning-integrating method to address the issue of constructing shape functions for panel units, resulting in a semi-analytical solution method for solving the dynamic characteristics of panel units. The new method establishes two independent sets of shape functions governing the displacement of the plate and edge beams and uses structural sealant to form a deformation-coordinated whole between the two. The truncation numbers of the Ritz function are further investigated to develop a method for obtaining high-precision natural frequencies using a small number of Ritz functions. The accuracy of the new method is validated with three numerical cases and two laboratory experiments. The proposed method, applicable to rectangular panel units, significantly simplifies the dynamic characteristics analysis. Additionally, a Ritz function truncating formula was proposed. The computational efficiency of the proposed method is higher than that of the finite element method in solving eigenvalue problems of low-order modes.

Key Words
dynamic characteristics; energy method; free vibration; glass curtain wall; panel unit

Address
Kun Jiang: Department of Civil Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Haidian District, Beijing 100083, China
Wenjing Ouyang: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, China
Danguang Pan: Department of Civil Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Haidian District, Beijing 100083, China
Yue Wang: Department of Civil and Architectural Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
Si-Wei Liu: Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 11 Yuk Choi Road, Hung Hom, Kowloon, Hong Kong, China

Abstract
This study investigates the experimental and analytical buckling behavior of two-dimensional perforated equal-angle cold-formed steel (CFS) members subjected to pure axial compression. Unlike previous studies that primarily focused on solid or unstiffened CFS sections, the present work explores the influence of perforation and varying stiffener spacing on the structural stability of built-up angle sections. The specimens were tested under pinjointed boundary conditions, with and without intermediate stiffeners placed at 50 mm, 100 mm, and 150 mm spacing. Experimental results revealed that reducing the stiffener spacing significantly enhances the buckling capacity, with the 50 mm spacing configuration exhibiting the highest ultimate stress and improved structural integrity. A nonlinear finite element (FE) model incorporating geometric imperfections was developed using ABAQUS and validated against the experimental results. The close agreement in failure load and deformation patterns confirms the reliability of the FE model. The validated model was further utilized for a parametric analysis to examine the effect of stiffener spacing under different boundary conditions (bottom fixed–top free and bottom fixed–top pinned). The results contribute new insights into optimizing stiffener arrangements for improved buckling resistance in perforated CFS angle members.

Key Words
ABAQUS; buckling modes; cold formed steel; finite element analysis and structural integrity; perforated equal angle section; stiffener spacing

Address
Priyanka R. Bhivgade, Keshav K. Sangle, Umesh A. Maske: Veermata Jijabai Technology Institute, Structural Engineering Department, Mumbai, India

Abstract
With the global increase in greenhouse gas emissions, the need for economically and environmentally friendly solutions in the construction industry has never been more urgent. This study aims to propose a multi-objective optimization problem formulation for prestressed composite steel and concrete beams. The objective functions considered are the minimization of the final cost and CO2 emissions from the materials used in their fabrication and the maximization of the live load capacity that the beam can support. Constraints include the requirements for composite steel and concrete elements according to Brazilian standards. The Multi-objective Particle Swarm Optimization (MOPSO) algorithm was implemented to solve the optimization problem and generate the Pareto fronts. Examples demonstrating the solution's effectiveness were compared with examples from the literature. The Pareto fronts show that different solutions can be found for the same load; the best results were obtained when using concrete with a compressive strength exceeding 45 MPa, reaching a maximum value of 50 MPa. Steel is the primary material contributing to both cost and CO2 emissions, while concrete is the second-largest contributor to final CO2 emissions. According to the results, searching for materials with greater resistance and low environmental impact is still necessary.

Key Words
CO2 emission and maximum load; cost; multi-objective optimization; prestressed steel and concrete composite beam

Address
Élcio Cassimiro Alves, Abner Endrye Pimentel de Almeida: Department of Civil Engineering, Federal University of Espirito Santo, Av. Fernando Ferrari, 514, Goiabeiras, Vitória, Espírito Santo, Brazil

Abstract
Autoclaved aerated concrete has garnered increasing attention due to its structural capabilities, owing to its high ratio of strength to weight and its minimal bulk density. The autoclaved aerated concrete has a notable benefit in its lightweight nature, which proves advantageous for seismic performance in areas prone to earthquakes. The objective of this research is to investigate the response of a half-scale unreinforced masonry structure, constructed with autoclaved aerated concrete, to seismic forces through the utilization of shake table tests. The building prototypes were subjected to seven distinct simulated earthquake forces using a shake table. Incremental seismic data were employed to evaluate the structural damage condition of the building. For the purpose of examining structural deterioration in a controlled setting, ambient vibration measurements were taken prior to and after seismic excitation. These measurements allowed for the determination of the dynamic properties of the masonry structure in both undamaged and damaged phases, which were then assessed for consistency with finite element analysis findings. The similarity in the results is satisfactory. In the undamaged condition, there was a 3.30% variance between the natural frequencies obtained through experimental and numerical means, while in the damaged state, this difference increased to 4.23%. Although the model exhibited satisfactory earthquake performance in the destructive earthquake data, it exhibited a brittle behavior in the sinusoidal wave with high acceleration levels and was severely damaged to the collapse level.

Key Words
ambient vibration test; autoclaved aerated concrete; finite element analysis; shake table test; unreinforced masonry

Address
Ali Kaya: Department of Architecture, Artvin Çoruh University, Artvin, Türkiye
Suleyman Adanur: Department of Civil Engineering, Karadeniz Technical University, Trabzon, Türkiye
Fezayil Sunca: Department of Construction Technologies, Karadeniz Technical University, Trabzon, Türkiye
Ali F. Genç: Department of Civil Engineering, Karadeniz Technical University, Trabzon, Türkiye
Murat Gunaydin: Department of Civil Engineering, Karadeniz Technical University, Trabzon, Türkiye
Ahmet C. Altunisik: Department of Civil Engineering, Karadeniz Technical University, Trabzon, Türkiye; Earthquake and Structural Health Monitoring Research Center, Karadeniz Technical University, Trabzon 61080, Türkiye; Dynamic Academy Software Construction Industry Trade Ltd. Co., Trabzon, Türkiye

Abstract
This study investigates the nonlinear dynamic response of rotating cylindrical shells made of axiallyfunctionally- graded graphene-platelet reinforced metal-foam (AFG-GPLRMF) under low-velocity impact in thermal conditions. Three distinct distribution patterns of graphene platelets (GPLs) are examined, including both uniform and functionally graded distributions through the shell's thickness. Material properties of the GPL-reinforced composites are determined using a temperature-sensitive micromechanical model. The governing equations are formulated based on nonlinear Donnell's shell theory, incorporating von Kármán geometric nonlinearity. Through numerical simulations employing the Runge-Kutta method, parametric studies are conducted to evaluate the effects of various factors including: initial geometric defects, rotational speed, boundary constraints, GPL dispersion patterns, foam distribution characteristics, porosity parameter, GPL concentration, thermal variation, impactor dimensions and velocity, applied axial loads, and damping properties on the impact response characteristics.

Key Words
axially functionally graded; cylindrical shells; low-velocity impact; spinning motion

Address
Gui-Lin She, Yu-Jian Ren, Ao Li: College of Mechanical and Vehicle Engineering, Chongqing University, Chongqing 400044, China

Abstract
Recent studies on coupled shear walls (CSW) have underscored the influence of local wall shear on their overall deformation behavior. Recognizing this mechanism has proven essential to minimize the discrepancies often observed when CSW are represented by the classical sandwich beam model. Although several generalized analytical formulations have been developed for vibration and stability assessments, their use is still constrained by their mathematical complexity and the requirement of programming skills or advanced analytical proficiency. To provide a simpler yet theoretically consistent alternative, this paper proposes approximate analytical expressions derived from a continuous Double-Beam Systems Timoshenko-type model that explicitly incorporates the local shear mechanism of the walls. The horizontal displacement induced by a generic static lateral load is decomposed into three independent subsystems: a bending-shear beam, a bending beam, and a shear beam. From these components, simplified eigenvalue relations are obtained, enabling direct evaluation of the fundamental vibration frequency and the global critical buckling load. By combining the eigenvalues of the three subsystems through Dunkerley

Key Words
approximate analytical solution; coupled shear walls; fundamental frequency; generalized continuous model; global critical buckling load; local shear deformation of the wall

Address
Mao Cristian Pinto-Cruz: 1Department of Civil and Environmental Engineering, Pontifical Catholic University of Rio de Janeiro, Rua Marquês de São Vicente 225, 22451-900 Rio de Janeiro, Brazil; Department of Civil Engineering, National University of Engineering, Avenue Túpac Amaru 210, 15333 Lima, Peru

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