In the process of designing an economical structure, safety along with total cost must be balanced. This can be attained by design optimization, however the complex nature of the algorithms involved hinders its application. Further, there is a severe lack of research on the optimization of reinforced concrete (RC) isolated footings. Therefore, the main objective of this research is to develop a user-friendly tool for the optimization of RC isolated footings using advanced metaheuristic algorithms to make it more practical and convenient to adopt for design optimization. For this purpose, a spreadsheet-based interface is created in which input parameters from the original design can be entered to find the best option for the minimum cost design. The Evolutionary Algorithm (EA) and the Genetic Algorithm (GA) are used as metaheuristic techniques for optimization. The original design of four examples from the literature is compared with the optimized design obtained from the developed tool to demonstrate its efficiency. For the considered case studies, cost-saving of up to 44% has been obtained. Furthermore, a parametric investigation for the minimum cost objective using the GA has been performed through which a detailed analysis of geometric reinforcement and material strength variables is conducted. The results lead to the derivation of useful thumb rules for the economical design and proportioning of isolated footings.
In the past, many studies have been conducted on the optimization of reinforced concrete (RC) structures. These studies have demonstrated the effectiveness of different optimization techniques to obtain an economical design. However, the use of optimization techniques to an obtain economical design is not so practical due to the difficulty in applying most of the optimization techniques to achieve an optimal solution. The RC beam is one of the most common structural elements encountered by a practising design engineer. The current study is designed to highlight the potential of the Solver tool in MS Excel as an easy-to-use option for optimizing the design of simply supported RC beams. A user-friendly interface was developed in a spreadsheet in which beam design parameters from a typical design can be entered and an economical design can be obtained using the Evolutionary Algorithm available in the MS Excel Solver tool. To demonstrate the effectiveness of the developed optimization tool, three examples obtained from the literature have been optimized. The results showed that up to 24% economical solution can be obtained by keeping the same material strengths that were assumed in the original design. However, if material strength is also considered as a variable, up to 44% of the economical solution can be obtained. A parametric study was also conducted to investigate the effect of different design variables on the economical design of simply supported RC beams and to derive useful rules of thumb for their design and proportioning, with the objective of cost minimization. The results of the parametric study suggest that the grade of the reinforcing steel is one of the most influential factors that affect the cost of simply supported RC beams. Practicing engineers can use the trends derived from this research to further refine their optimal designs.
This paper aims to facilitate in the reduction of issues related to agricultural wastes such as disposal and burning by incorporating two widely produced agricultural wastes in Pakistan, i.e., Rice Husk and Wheat Straw, in gypsum false ceiling plates to develop an eco-friendly construction product. There is an increased focus of research on the development of such eco-friendly gypsum products to make the use of gypsum sustainable. Composites containing agricultural residues with four different replacement levels of 2.5%, 5%, 7.5%, and 10% by weight are developed along with a control mix containing 100% gypsum. The physical, mechanical, and thermal properties of the developed composites are investigated. Also, the false ceiling plates are made using the developed composites and their flexural behavior is compared with that of the control specimen containing 100% gypsum. The results showed that density and shore C hardness reduced with increasing the amount of agricultural waste while the water absorption remained similar up to a dosage of 7.5%. Except for the 10% wheat straw dosage, flexural and compressive strength of developed composites showed a decrease with the increase of wheat straw and rice husk dosages but remained above the acceptable values of 1 MPa and 2 MPa, respectively, as per BS EN 14246. For the same replacement level, the composites containing wheat straw showed relatively inferior mechanical properties results as compared to those containing rice husk. The thermal conductivity test showed better thermal performance of the composite mixes as compared to the reference mix. The bending test on false ceiling plates showed that all the plates satisfied the minimum flexural strength criteria as per BS EN 14246 and the flexural strength of plates increased up to a replacement level of 5% for both the agricultural wastes.
Burnt clay bricks are widely used as a construction material in Pakistan, and their testing for quality confirmation is frequently needed for new and old bricks used in existing structures. The destructive testing methods are time-consuming and not always feasible for testing the bricks used in existing structures. The current study investigated the feasibility of using the ultrasonic pulse velocity (UPV) test as a non-destructive technique to assess the quality of both new and old bricks in masonry structures. A relationship was developed after performing the UPV test followed by a compression test on burnt clay brick samples of five different ages acquired from different sources. The acquired brick samples ranged from new to a century old. Consequently, as a novel contribution, brick quality assessment criteria based on UPV were proposed according to which a UPV value greater than 3000 m/s represents an excellent first-class brick whereas a UPV value lower than 2000 m/s shows a second-class brick. Further, the effectiveness of the UPV test to assess the compressive strength of old bricks was demonstrated with a case study of a 100-year-old masonry structure. The research concluded with the remarks that the compressive strength of bricks can be assessed with reasonable accuracy using the UPV test. The developed quality assessment criteria can be used to quickly check the quality of new and old burnt clay bricks.
Recent achievement of research on soil-structure interaction (SSI) is reviewed, with a main focus on the numerical analysis. The review is based on the continuum mechanics theory and the use of high-performance computing (HPC) and clarifies the characteristics of a wide range of treatment of SSI from a simplified model to a high fidelity model. Emphasized is that all the treatment can be regarded as the result of the mathematical approximations in solving a physical continuum mechanics problem of a soil-structure system. The use of HPC is inevitable if we need to obtain a solution of higher accuracy and finer resolution. An example of using HPC for the analysis of SSI is presented.