Abstract
Energy Flow Analysis (EFA) provides an efficient approach for high frequency vibration analysis by
modeling time-averaged energy density distributions. This study applies EFA to investigate vibroacoustic behavior in
orthotropic plates subjected to high frequency excitation. Governing equations of motion are derived using Classical
Plate Theory (CPT), First Order Shear Deformation Theory (FSDT), and Higher Order Shear Deformation Theories
(HSDT). Wave propagation parameters like wave number and group velocity are extracted from each plate theory
and their accuracy is compared. An energy density formulation is also developed based on the classical solution of
equations of motion. EFA solutions show that HSDT yields more accurate predictions of wave parameters compared
to CPT and FSDT, especially at very high frequencies, since it accounts for shear deformation effects more precisely.
The EFA results are validated against classical energy density solutions, demonstrating acceptable accuracy with less
than 4dB difference in the far-field region. Furthermore, comparisons reveal that HSDT provides more valid
solutions than FSDT when analyzing thick plates, for both classical and EFA methods. This study demonstrates the
effectiveness of EFA for high frequency vibration analysis in orthotropic plates. HSDT improves the modeling of
important shear deformation effects at high frequencies. EFA generates computationally efficient solutions while
maintaining acceptable accuracy levels. The proposed methodology enhances vibroacoustic characterization and
design of orthotropic plate structures subjected to high frequency excitation.
Key Words
energy flow analysis; high frequency vibrations; orthotropic plate; shear deformation theories
Abstract
In this paper, a simplified model of corrugated panels using a newly developed third-order shear
deformation theory (DTSDT) is presented to investigate the buckling and vibrational behavior of the panels. The
finite strip method is also used for the dynamic and static analysis of corrugated plates. Using this method, a
corrugated panel can be equated with a homogeneous orthotropic plate that has different material properties in two
perpendicular directions. Eventually, the stiffness, geometric, and mass matrices of the whole structure are derived.
The homogenization model can be applied to any corrugated geometry, such as trapezoidal and sinusoidal plates.
This method is based on the equalization of the strain energy between the homogenized plate and the primary
corrugated plate, so that by using the equalization of energies, the ABD matrix for the homogenized plate is obtained
based on third-order shear deformation theory (TSDT). Additionally, since the corrugation of the plate is in one
direction, the ABD matrix of the homogeneous plate can be assumed to be diagonal. The results of static buckling
and vibration of the corrugated plate are compared with numerical example values from previous studies.
Key Words
buckling; corrugated plate; developed TSDT; homogenous method; vibration
Address
Ali Ghiamy:Department of Civil and Transportation Engineering, University of Isfahan, Isfahan 81746-73441, Iran
Hossein Amoushahi:Department of Civil and Transportation Engineering, University of Isfahan, Isfahan 81746-73441, Iran
Mohammad Hesam Salar:Department of Civil and Transportation Engineering, University of Isfahan, Isfahan 81746-73441, Iran
Abstract
Cracking of concrete slab in the negative moment area of steel-concrete composite continuous beam
bridge is a fundamental issue affecting structural durability. The concrete slab cracks and the service crack width are
determined according to factors associated with design, construction and operation conditions. In order to consider
uncertainties involved in these factors, this paper conducted a probabilistic analysis on the concrete cracking in the
negative moment area of steel-concrete composite continuous beams. A comprehensive risk probability assessment
method for concrete cracking in negative moment area is proposed. In the probabilistic analysis, risk sources
affecting the stress and maximum crack width in concrete slab are identified and quantified. The service crack width
prediction model was proposed based finite element analysis, and the probability of cracking and service crack width
exceeds the limit is calculated. A time-dependent probabilistic analysis is conducted for in-service composite bridge
deck through modify the reinforcement stress and non-uniform coefficient considering the strain increment caused by
concrete creep in tension and shrinkage. Based on the sensitivity analysis, cracking control recommendations are
taken from the perspectives of constructability and material properties, and results revealed that the proposed control
recommendations can effectively reduce the risk of concrete cracking in the negative moment area.
Key Words
concrete cracking; cracking control measures; negative moment area; risk probability; steel
concrete composite continuous beam
Address
Huibing Xie:1)School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China
2)Key Laboratory of Safety and Risk Management on Transport Infrastructures,
Ministry of Transport, Beijing 100044, China
Bing Han:School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China
Yue Sun:School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China
Siyi Jia:School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China
Wutong Yan:School of Civil Engineering, Beijing Jiaotong University, Beijing, 100044, China
Abstract
This study investigates the fire resistance of partially encased composite (PEC) members through
experiments and finite element (FE) analysis. Fire tests were conducted on three T-shaped PEC beams and six
rectangular PEC columns, each with fire-proof coating, exposed to the ISO 834 standard fire curve. Results showed
that all beams experienced flexural deformation and concrete cracking, and satisfied the two-hour fire resistance
requirement. FE models were developed to simulate temperature development, distribution, and thermo-mechanical
behavior, with numerical results matching experimental outcomes. A parametric study was conducted to investigate
the effects of coating thickness, section dimensions, and load ratio on temperature development and fire resistance. It
was found that increasing the coating thickness from 7.0 mm to 11.0 mm reduced the peak temperature by
approximately 150°C after 3 hours of fire exposure. Additionally, the load ratio significantly impacted the fire
resistance of PEC beams, while section dimensions had minimal influence. Based on these findings, a practical
design method for predicting the load capacity of PEC beams under elevated temperatures was proposed, showing
good agreement with experimental and FE results.
Key Words
fire-proof coating; fire resistance; fire tests; numerical simulation; partially encased composite
members; practical design method
Address
Hao Tang:College of Civil Engineering, Tongji University, Shanghai 200092, China
Shouchao Jiang:1)College of Civil Engineering, Tongji University, Shanghai 200092, China
2)State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China
Yanbo Wang:College of Civil Engineering, Tongji University, Shanghai 200092, China
Zhengjun Liu:College of Civil Engineering, Tongji University, Shanghai 200092, China
Shaojun Zhu:College of Civil Engineering, Tongji University, Shanghai 200092, China
Abstract
As essential components in arch bridge suspenders, high-strength steel wires are highly susceptible to
environmental corrosion, significantly degrading their mechanical properties. When subjected to overloading
vehicles, these corroded wires experience high-strain low-cycle fatigue loading, which further accelerates their
property degradation and increases the risk of premature failure. To address the issue of insufficient understanding of
the mechanical behavior of corrosion-damaged high-strength steel wire under these conditions, a large arch bridge in
Guangxi was selected as the case study. Through the equivalent conversion of actual environmental conditions and
vehicle loads, the appropriate test parameters were determined. Systematic accelerated corrosion tests and subsequent
high-strain, low-cycle fatigue loading tests were conducted on high-strength steel wires, followed by an evaluation of
their residual mechanical properties. The results demonstrate that corrosion significantly reduces the ultimate tensile
strength and yield strength of steel wires, with reductions of 31.68% and 34.41%, respectively, after 14 days of
accelerated corrosion. The fatigue stress amplitude causes a non-monotonic variation of the ultimate tensile strength,
characterized by strengthening followed by degradation. A particularly notable finding is the significant synergistic
effect between corrosion and low-cycle fatigue. Under identical stress amplitude, the change in ultimate tensile
strength after 14 days of corrosion was 12.15 times greater than that of uncorroded wires. These findings reveal the
degradation mechanism of corroded high-strength steel wires under high-strain low-cycle fatigue, providing a
theoretical foundation for condition assessment and maintenance strategies for high-strength steel wires in existing
bridge suspenders.
Key Words
accelerated corrosion tests; bridge suspender; high-strain low-cycle fatigue loading tests; high
strength steel wires; mechanical properties
Address
Zimo Zhang:1)College of Transportation, Jilin University, Changchun 130025, China
2)School of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China
Guojin Tan:College of Transportation, Jilin University, Changchun 130025, China
Hua Wang:Guangxi Transportation Science and Technology Group Co., Ltd., Nanning 530007, China
Tao Yang:School of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China
Abstract
This paper aims to propose hybrid machine-learning (ML) models to predict the ultimate shear strength
of reinforced concrete (RC) columns with both circular and rectangular sections. Fifteen optimization algorithms
from five groups, including the Bio-based, Evolution-based, Human-based, Math-based, and Swarm-based
optimization algorithms were used to optimize the hyperparameters of the eXtreme Gradient Boosting (XGB)
model. These ML models were trained with a dataset consisting of 497 experimental data points of the RC columns
and evaluated with coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE),
and a20-index metrics. It was found that the XGB model optimized with the Battle Royale Optimization (BRO)
algorithm (BRO-XGB) shows the best performance according to all metrics. In particular, it achieved an R2 score of
0.971 and an a20-index score of 0.966. This model also demonstrates its superiority in accuracy when compared to
design codes and previous studies. The proposed model achieved an RMSE value less than half, and an MAE score
only one-fourth, of those reported in the best previous study. Additionally, the uncertainty analysis was conducted to
estimate the convergence of the prediction results and the sensitivity values of the input parameters. Finally, a support
tool was developed, leveraging the BRO-XGB model's predictions, to suggest appropriate RC column dimensions
and material strengths. This tool facilitates easier parameter selection and substantially shortens the preliminary
design, without requiring knowledge of ML, optimization, or programming.
