This study aimed to evaluate the structural behavior of sustainable hybrid concrete produced using recycled plastic as a partial sand replacement at percentages of 0%, 5%, 10% and 15% with the addition of 2% recycled steel wire fibers by volume. The focus was on improving the bond performance between old and new concrete under bending loads. The experimental program included compressive strength tests cubes, split tensile strength tests cylinders and slump tests for fresh concrete. Additionally, bending tests were conducted on prisms measuring 10 x 10 x 40 cm at contact angles of 30 degrees, 45 degrees and 60 degrees with various surface treatments applied to increase the roughness of the face. The results showed a gradual decrease in mechanical properties with increasing plastic content. The compressive strength decreased by 16% when 15% of the sand was replaced with a compressive strength of 19.24 MPa recorded at 28 days. The bond angle also significantly affected flexural strength and failure mode 60 degrees angle reduced strength by 17%-20% compared to smaller angles. Conversely, surface treatments applying horizontal and radial roughening of 1 cm improved bond strength by 16%-26%, while reducing the likelihood of surface bond failure in samples with high plastic content. These results suggest the possibility of producing sustainable concrete using recycled materials without significantly impacting structural performance and in an environmentally friendly manner, provided that the concrete's surface bonding properties are improved to ensure effective structural behavior.
The single plate shear (SPS) connection is a cost-effective choice for beam to column connections. The failure detection method for the connections helps people to respond and receive an early warning, allowing them to take action earlier and prevent serious consequences. Thus, a quick solution is needed to address the structural safety monitoring issue and predict the response of the SPS connection with accuracy and speed. The present study recommends the behaviour of SPS connection to predict its failure mode using long-short term memory (LSTM) networks. The LSTM models were designed utilising the datasets generated by applying a finite-element method (FEM) of SPS connection. Experimental Validated model was used for finite element analysis of 48 SPS connections with different seven parameters like distance, the depth of the shear plate connection plate, thickness of web, thickness of shear plate, the number of bolt columns, Grade of bolts, the beam span, and a number of common wide flange beam shapes. The LSTM model utilise von Mises stresses for analysing the failure mode of the SPS connection was compared to the results of the artificial neural network (ANN) and the FEM. The output of an LSTM model was nearly identical to an ANN model, with ANN model performing slightly better. In all three outputs, the ANN model's performance is satisfactory (r > 0.8). The training and testing of the ANN models required an average of six seconds, whereas the analysis of the deep LSTM network consumed almost an hour. The comparison shows that the ANN model predicted stresses more accurately than LSTM, at least for the current work, which reduces the necessity of using LSTM for the said task.
Developing of approaches for evaluation of structural life of load-bearing functionally graded beam structures containing longitudinal cracks under creep is a current problem. This is due to the fact that in many cases longitudinal cracks are observed during routine maintenance check of such structures. The present paper novelty is that an approach for evaluating the effect of longitudinal cracks on structural life of functionally graded load-bearing beams which exhibit non-linear creep is developed. In this relation, general time-dependent solution of the strain energy release rate (SERR) is derived. The beams under consideration are functionally graded in the thickness direction. The crack is located arbitrary along the thickness. The creep behavior is described by non-linear stress-strain-time relationship written in general form. The solution of the SERR is derived by analyzing the time-dependent complementary strain energy. Two cases of behavior (beams with identical creep behavior in tension and compression and beams with asymmetrical creep behavior in tension and compression) are considered. The general solution is applied to evaluate the effect of a longitudinal crack on the structural life of a cantilever beam. The time-dependent SERR in the cantilever beam is obtained also by considering the balance of the energy for check-up of the general solution. It is found that the structural life is extended with increasing thickness to width ratio of the beam. However, the life of the structure is shortened as the crack length to beam length ratio increases. Furthermore, a beam with asymmetric creep behavior in tension and compression has a shorter structural life than that of a beam with identical creep behavior.
Because of its simplicity, quickness, and high accuracy, the frequency-based method has become one of the most used techniques for cable force identification in engineering. Several scholars have developed cable force identification methods, such as the "Three Criteria method", based on the traditional frequency method. These methods are appropriate for complex cable systems, the majority of which have short, thick cables and relatively complex supporting circumstances. The proposed methodology aims to extract local modal information of cables from global modal information, thereby establishing a cable force-frequency correlation model that incorporates the influence of the overall structural system. Based on the "Three Criteria method", this study conducts numerical experiments under a range of operating conditions to systematically investigate the threshold setting criteria for the Modal Assurance Criterion (MAC) values for the purpose of more precisely extracting local vibration modes of the cables. Ultimately, practical engineering was used to confirm the efficacy of the criteria establishing process.
Efficient routing of multi-compartment vehicles is a critical challenge in logistics, as it involves optimizing travel distance and load distribution while considering multiple constraints. Traditional vehicle routing algorithms often fail to address the complexities of compartmentalized cargo, leading to inefficiencies in delivery operations and increased costs. This study aims to bridge this gap by introducing a Three-Dimensional Ant Colony Algorithm (3D-ACA) for optimizing Multi-Compartment Vehicle Routing (MCVR). This research aims to minimize total travel distance while ensuring proper allocation of goods to vehicle compartments and adherence to delivery time constraints. The approach involves formulating the Multi-Compartment Vehicle Routing Problem (MCVRP) as an optimization model and applying 3D-ACA to generate efficient routing solutions. Unlike conventional methods, which primarily focus on shortest-path algorithms, this study incorporates three key factors, route efficiency, compartment constraints, and time windows, into a single optimization framework. The novelty of this research lies in the three-dimensional adaptation of the ant colony algorithm, which extends the standard routing problem to include compartment-based decision-making. This approach provides a more realistic and practical solution for logistics companies aiming to improve fleet utilization, reduce costs, and enhance operational efficiency. The proposed 3D-ACA significantly improved key performance metrics, including a 15.6% reduction in travel distance compared to Ant Colony Optimization (ACO), up to 17% lower operational costs, and over 95% feasibility rates across datasets. It also demonstrated superior scalability by solving large-scale problems (150 nodes) under 45 minutes, outperforming traditional methods such as GA and MIP in efficiency and constraint satisfaction.
