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Abstract
The reinforcement technology for rib-to-deck weld cracks in orthotropic steel deck should be both efficient and lightweight, particularly for multi-crack reinforcement within a single compartment, to avoid adding excessive weight that could affect the structural stress. In this paper, a lightweight reinforcement technology using ribbed angle steel was proposed. By conducting tests and numerical simulations, the reinforcement effect of ribbed angle steel for rib-to-deck weld cracks was analyzed, with a focus on the influence of stiffener thickness, spacing, and arrangement on the reinforcement effect. Reasonable parameters were then suggested. The effectiveness of the proposed technology and parameters was demonstrated through a real bridge simulation. The results show that ribbed angle steel, compared to angle steel, offers effective reinforcement while being lighter in weight. The failure behaviour of ribbed angle steel is consistent with that of plain angle steel, and the quality of adhesive layer construction should be strictly controlled during actual implementation. Increasing the thickness of the stiffeners can enhance the reinforcement effect, while increasing the spacing between stiffeners can reduce the reinforcement effect. When using ribbed angle steel with 4 mm thick angle steel, 6 mm thick stiffeners, and 20 mm stiffener spacing to reinforce cracks, the reinforcement effect is superior to that of 10 mm plain angle steel.

Key Words
crack reinforcement technology; orthotropic steel deck; parameter analysis; rib-to-deck weld crack; ribbed angle steel

Address
Yuqiang Gao, Zhongqiu Fu, Xuekun Cao and Bohai Ji:College of Civil and Transportation Engineering, Hohai University, No. 1 Xikang Road, Nanjing, China

Abstract
Enriched meshfree methods have been effectively used to predict the stress intensity factors (SIFs) and crack trajectories for homogeneous structures, but their applications to heterogenous materials were rarely reported. In this context, an enriched Petrov-Galerkin natural element method (PG-NEM) is introduced to simulate and examine the crack growth in 2-D heterogeneous functionally graded (FG) porous plates. The global displacement is approximated using Laplace interpolation (L/I) functions and enriched by introducing the crack-tip singular displacement and stress fields. The mixed-mode SIFs of FG plates characterized by the spatially varying elastic modulus are computed by the modified interaction integral method, and the crack trajectories are predicted by the maximum principal stress (MPS) criterion and the equivalent mode-I SIF. The advantage of proposed method is verified by comparing with the unriched PG-NEM and ANSYS. It is found that the prediction accuracy in crack trajectory is remarkably improved such that the crack trajectory of present method coincides well with one of ANSYS. Moreover, the present enriched method successfully simulates the crack trajectories of FG plates with the porosity as well as the spatially varying elastic modulus, and it is found that the crack growth characteristics are remarkably influenced by these parameters.

Key Words
2-D enriched PG-NEM; crack growth length; crack propagation trajectory; crack propagation; exponentially varying elastic modulus; functionally graded porous plates; porosity distribution

Address
J.R. Cho: Department of Naval Architecture and Ocean Engineering, Hongik University, Sejong 30016, Korea

Abstract
The proposed model introduces a novel approach to predicting stiffness and Poisson's ratio degradation in metal ceramic sandwich plates, specifically under hygro-thermo-mechanical loadings. Unlike previous models such as the Equivalent Constraint Model (ECM), this model incorporates an inter-laminar adhesive layer to transmit normal and shear stresses between the ceramic and metallic layers, significantly enhancing its accuracy in environmental stress simulation. By extending the shear lag model to include temperature and humidity effects, this model provides a more precise prediction of mechanical response under extreme operational conditions. Validation against experimental data further establishes the model's reliability, showing a substantial improvement in predictive capability. The Analysis reveals that both stiffness and Poisson's ratio degrade progressively with increasing crack density, temperature, and concentration, with the extent of degradation varying across metal content. Validated against experimental data, this model advances scientific understanding of metal-ceramic composite performance and provides a practical, accurate tool for designing resilient composites in demanding sectors such as aerospace and automotive, where environmental resilience is critical.

Key Words
hygro-thermo-mechanical; metal ceramic; poisson's ratio; shear-lag; stiffness; transverse cracking

Address
Mohamed Khodjet-Kesba:Aeronautical Sciences Laboratory, Institute of Aeronautics, and Space Studies, University of Blida 1, BP 270 Blida 09000, Algeria Zineb Mouloudj:Aeronautical Sciences Laboratory, Institute of Aeronautics, and Space Studies, University of Blida 1, BP 270 Blida 09000, Algeria Billel Boukert:Aeronautical Sciences Laboratory, Institute of Aeronautics, and Space Studies, University of Blida 1, BP 270 Blida 09000, Algeria

Abstract
The examination of crack growth's energy consumption in concrete structures has been of primary importance since the origin of fracture mechanics. A quasi-brittle material like concrete heavily depends on the available fracture energy for reliable design of structures and for modeling the failure spill. Yet, the approaches to evaluate the initial fracture energy of concrete (IFEC) remain unsatisfactory because of complexity, time consuming costs and monetary budget constraints of orthodox laboratory experiments. In this regard, this research suggested two predictive models: one is AdaGrad gated recurrent unit (AdaG-GRU) and other is adaptive response surface method with KNN (ARSM-KNN). Chi-square automatic interaction detection-decision tree (CHAID-DT) and automatic linear regression with boosting overfitting criteria (ALR-OPC) were also included in the ensemble of the models, along with the stacking approach. Data from three-point load tests for single-edge notched beams (SENB) conducted in the laboratory were used to train and validate these models. With the introduction of the new empirical model using ALR-OPC, different scenarios of concrete strength were incorporated. The training was conducted on a dataset which consisted of five features of concrete and one dependent variable as compressive strength, aged at 28 days, and indexed by 500 datapoints, divided in 85 percent training and 15 percent testing set. These features included maximum size of coarse aggregate and the ratio of water to cement. Between the offered metrics, multitask sensitivity analysis and importance ranking identified the most crucial features of the IFEC as compressive strength and water-to-cement ratio. These results proved the strongest correlation between the predicted and observed values using stacking-ensemble and AdaG-GRU models, which obtained the highest accuracy at R2 = 0.98 and 0.95, respectively. Empirical laboratory tests and advanced machine learning based models also agreed that the optimum water-to-cement ratio of 0.2 to 0.4 resulted in the maximum IFEC. In addition, the increase of IFEC values with time was observed as maximum aggregate size and specimen age were increased from 1 mm to 35 mm and 3 to 180 days, respectively.

Key Words
concrete; hybrid-optimized machine learning; initial fracture energy of concrete; stacking-ensemble

Address
Manish Kewalramani:Department of Civil Engineering, College of Engineering, Abu Dhabi University, Abu Dhabi, UAE Hanan Samadi:IRO, Civil Engineering Department, University of Halabja, Halabja, 46018, Iraq Arsalan Mahmoodzadeh:IRO, Civil Engineering Department, University of Halabja, Halabja, 46018, Iraq Nejib Ghazouani:Mining Research Center, Northern Border university, Arar 73222, Arar, Saudi Arabia Abdulaziz Alghamdi:Department of Civil Engineering, University of Tabuk, Tabuk, Saudi Arabia Ibrahim Albaijan:Mechanical Engineering Department, College of Engineering at Al-Kharj, Prince Sattam Bin Abdulaziz University, Al Kharj 16273, Saudi Arabia Mohd Ahmed:Department of Civil Engineering, College of Engineering, King Khalid University, PO Box 394, Abha 61411 Kingdom of Saudi Arabia

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