Journal of Civil Engineering Researchers
Volume:6 Issue: 4, Autumn 2024

This study investigates and compares the performance of reinforced concrete buildings containing SMA bars and steel bars as longitudinal reinforcement of column.The use of this type of material is to reduce permanent deformation in the structure due to the reversible properties of these materials.First, a laboratory specimen of a reinforced concrete column with shape memory alloy bars was modeled in the OPENSEES software and the modeling method was validated.Then, 3- and 5-story concrete frames, in two states, reinforced with steel bars and SMA bars, under nonlinear static and nonlinear time history analyses with near-fault records were analyzed.The results of the time history analyses showed that, although the use of SMA bars significantly reduces the residual deformation of the structure, it does not show a significant effect on reducing the maximum displacement of the structure.The maximum rotational deformation of columns in frames with SMA bars is greater than of frames with steel bars.However, SMA bars have greatly reduced the permanent rotational deformation of columns and reduced it to zero.The maximum drift of floors in frames with SMA bars increases slightly.The permanent drift of the structure in frames with SMA bars is significantly reduced.

In this review paper, the applications of machine learning, computational methods, and robotics to bridge design are considered to help improve structure integrity and resilience. It describes a variety of computational methods, including finite element analysis (FEA) and computational fluid dynamics (CFD), that have been used to calculate failure modes and evaluate the dynamic behavior of bridge structures in extreme conditions, such as earthquakes and floods. It also highlights robotics’ potential to streamline inspection techniques, showing new robotic systems for effective bridge monitoring. Additionally, it points out issues related to data shortages and implementation difficulty and presents future research priorities, such as the need for powerful machine learning algorithms and the use of Internet of Things (IoT) solutions for real-time monitoring. In summary, the paper highlights the life-changing impact of these technologies on the safety and reliability of bridge systems.

Recycled glass waste is one of the most attractive waste materials that can be used to create a concrete mix.Therefore, researchers focus on the production of concrete using recycled glass as an abrasive or as a pozzolanic material, but the use of recycled glass in the form of coarser particles to replace sand in concrete increases the alkali-silica reaction and this causes Unfavorable performance in the mechanical properties of concrete.To prevent this, microsilica is used to improve the strength and mechanical properties of concrete.In this research, after building the control mixing design, recycled glass was replaced with sand and silica foam as microsilica in four designs with a fixed ratio of 5% by weight of cement.The compressive strength test was performed at the ages of 7 and 28 days, and three samples were taken in each test, and a total of 24 cubic samples were tested.Tensile test, like compressive strength test, were tested at the ages of 7 and 28 days, which included two cylindrical samples in each test, and a total of 16 cylindrical samples were tested.The presence of silica foam in concrete causes adhesion and reduction of slump fluidity, and the highest slump fluidity was observed at 5% ratio.The result of testing the compressive strength and tensile strength of the concrete containing glass shards and silica foam had decreased in quality compared to the control mixing plan, which shows the unfavorable performance of coarse glass particles in the concrete structure.

This study investigates the mechanical properties of natural fiber-reinforced concrete (FRC) through the addition of natural fibers such as kenaf (KFRC), jute (JFRC), and coconut (CFRC). The evaluation focused on key properties including compressive strength, split tensile strength, and flexural strength. Fiber combinations were introduced in a fiber volume fraction of 0.5%, with fiber lengths standardized at 20 mm. A water-to-binder ratio of 0.44 was maintained for all mixes. Six specimens were tested for each parameter after a curing period of 28 days. The objective of this research was to assess the potential of natural fibers like kenaf, jute, and coconut for developing sustainable FRC while maintaining or improving its mechanical properties. Results demonstrated that the inclusion of natural fibers at the specified length and concentration positively influenced post-cracking flexural performance and splitting tensile strength. Among the tested combinations, FRC reinforced with jute fibers (JFRC) exhibited superior performance compared to other fiber combinations.

In this article, the optimal shape of the compound trapezoidal cross-section is presented by considering the deterministic constraints and the probabilistic constraint of channel flooding as uncertainty with the SPSA algorithm and with three discharge of 10, 50, and 120 (m^3/s). The objective function is to minimize the cost of excavation and lining, the design variables of depth and width of the canal bottom, side slopes and constraints include uniform flow, maximum and minimum velocity, water surface width and the overtopping probability. The values of the freeboard and the slope of the channel bed are fixed and equal to 0.5 meters and 0.0028, respectively. The results show that with the increase in overtopping Probability, the flow depth increases, but the side slopes, velocity and Froud number decrease. The cost of construction and the width of the bed, initially decreases with the increase of the overtopping probability, and at a certain value, the probability reaches its minimum value, and then with the increase of the overtopping probability, the cost of construction and bed width increases.

The objective of this study is to determine the technical, legal, and economic feasibility of establishing a heavy-duty paver block factory for the Municipal Decentralized Autonomous Government of Sigchos Canton. The methodology used included a non-experimental research approach, with an explanatory, descriptive, and correlational design. Surveys were conducted with the legal representatives of the parish councils to gather primary information, while secondary information was obtained through bibliographic and documentary review. The results from the market study reveal significant demand and acceptance from the parish representatives toward the production of vehicular pavers, supporting the need to improve local road infrastructure and economic development. A market opportunity was identified both in government projects and private initiatives, with an estimated daily demand of 2,800 paver units. As for the technical study, efficient production processes were designed, with rigorous quality control measures and an annual production capacity of 2,880,000 pavers. The administrative-legal analysis reflects a comprehensive and proactive approach to meeting legal and regulatory requirements, including the decision to establish a Corporation (S.A.) and obtaining the necessary permits for the factory’s operation. Finally, the financial study results indicate that the project is economically viable, with a positive Net Present Value (NPV), Internal Rate of Return (IRR), Payback Period (PBP), average profitability (AP), and Benefit-Cost Ratio (BCR), supporting the project's feasibility.