Scientia Iranica
Volume:30 Issue: 3, May-June 2023

The purpose of this study is optimal performance based design of municipal wastewater collection networks. Sewer deterioration decreases system performance over time and investigations have shown that diameter, slope, structural condition, length and burial depth are effective factors in hydraulic and structural deterioration. In this research first these factors were used to develop performance indicators based on velocity, depth of flow, burial depth, pipe slope and pipe length. Then, using the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and pipe diameter as decision variable, the optimal design of a case study was performed under different combinations of performance indicators. Part of Kerman's wastewater collection network which includes 20 manholes and 20 pipes and one outlet is considered as case study. The results showed that the pareto points in different combination of factors influencing the overall performance, are very similar and in all scenarios, the designs tend to increase the slope of the pipe, decrease the diameter and increase the depth of burial. It was observed that the performance of the network can be improved about 2 percent in case study and almost without imposing additional costs on the basic design.

Statistical pattern recognition has recently emerged as promising and effective set of complementary methods in structural health monitoring to assess the global state of structures. The aim of this paper is to detect nonlinearity changes resulting from damage by some efficient signal analysis methods. The primary idea behind these methods is to use raw measured vibration time-domain data without applying any feature extraction technique associated with the statistical pattern recognition paradigm. Firstly, statistical moments and central tendency measurements are applied as damage indicators to determine their changes due to damage occurrence. Subsequently, cross correlation and convolution methods are used to measure the similarity between the vibration time-domain signals in the undamaged and damaged conditions. The main innovation of this study is the capability of proposed signal analysis methods for implementing the nonlinear damage identification without extracting damage-sensitive features. In the following, numerical and experimental benchmark models are employed to demonstrate the performance of proposed methods. Results show that nonlinearity changes lead to a reduction in the values of cross correlation and convolution methods caused by damage. Moreover, some of the statistical criteria on the basis of the exploratory data analysis are applicable tools for the global structural health monitoring.

Dynamic analysis of cracked thin rectangular plates subjected to a moving mass first is investigated in this paper. To this end, the eigenfunction expansion method is utilized to solve the governing equation. For the first time, the intact plate orthogonal polynomials in combination with admissible crack functions as a composition, are employed in the eigenfunction expansion method formulation, required professional computer programming to solve the equation. The proposed approach guarantees upper bound of the true solution, which is the property of an appropriate numerical solution. Parametric investigation is performed to determine the effect of the moving mass weight, the moving mass velocity, the crack length, and the crack angular orientation as well as the plate’s aspect ratio, on the dynamic response of cracked plates. The results confirm, that the moving mass has a greater impact than the moving load on the dynamic responses of cracked plates. Furthermore, there is nonlinear relation among enhancing the dynamic responses of the cracked plates with various boundary conditions, and magnifying the moving mass weights, elevating the moving mass velocities, lengthening the crack length, raising the inclined crack angels as well as augmenting the plates aspect ratios.

In today's world, one of the most important and basic parts in urban developments is related to the creation and development of a projects with an infrastructure nature. Meanwhile, these development projects can implement under the public-private partnership (3P) projects that financial challenges are the main factor that can affect the success of the project. In this paper, a novel intuitionistic fuzzy soft computing-based ideal solution based on criteria importance determination and experts’ weights computations is tailored. In this sake, the criteria importance is computed based on presented intuitionistic fuzzy preference evaluation method and also the experts’ weights are determined by proposing an intuitionistic fuzzy utility degree technique. Moreover, the proposed approach is developed based on last aggregation process to decrease the data loss and cover the preferences judgments of experts thorough the method execution. Finally, a real case study is provided to indicate the process of the method execution and assess the effective criteria in 3P projects of urban development. In addition, a comparative assessment and a sensitivity analysis is considered to show the applicability and sensitiveness/robustness of the proposed approach, respectively.

This paper presents a new configuration for semi-supported steel plate shear walls to increase their efficiency. For this purpose, the infill steel plate is proposed to be a trapezoidal shape instead of a rectangular one. To find the most efficient inclination angle of lateral sides, a numerical parametric study was conducted. Five different values of inclination angle including 60, 75, 90, 105, and 120 degrees were considered. Furthermore, two thicknesses of 1.75 and 2.00 mm were considered for the steel plate. The area of the steel plate was the same for all the models. The models were analyzed using finite element software ABAQUS. Both geometric and material nonlinearity have been considered. To validate the finite element modeling, the available experimental results were used. According to the results, comparing to the wall with rectangular plate, the inclination angle of 60° increases the ultimate lateral strength and stiffness of the 1.75 mm-thick walls by 46% and 66%, respectively. Furthermore, a simple approximate model is presented to calculate the load-deformation response of the proposed wall using SAP 2000 program. Despite the simplicity of the method, the results were in good agreement with the results of ABAQUS.

In this study, the Vaiont landslide is simulated using an enhanced material point method (MPM) capable of modeling multi-body interactions with cohesive-frictional interfaces. The interface model accuracy is examined through several benchmark problems. Afterward, the capability of the numerical tool in the simulation of large deformations during a failure is demonstrated in two problems. After the verification phase, the Vaiont landslide is modeled considering three distinct elastoplastic bodies with cohesive-frictional interfaces. The calculated final configuration has excellent agreement with field observations. The effect of the number of masses contributed to the problem is investigated for the next step. Finally, the Vaiont landslide is modeled with rigid boundaries and a main sliding body. It is shown that the rigid boundary assumption may cause significant errors in the final geometry evaluation.

This paper is aimed at proposing a strengthening method for improving the seismic performance of unreinforced masonry (URM) brick walls. What is noteworthy regarding the proposed technique is the low price and easy application of polypropylene (PP) bands, which are widely used in the packaging industry. Three half-scale specimens were tested under cyclic lateral loading simultaneously with imposing a constant vertical load. First, the URM wall was tested up to a certain drift in which a reduction in lateral capacity was recorded. According to the crack pattern observed on the wall surface, a repair strategy was taken to upgrade the damaged wall in the shortest possible time and with the minimum manpower. In doing so, the horizontal PP bands were employed to wrap the wall. The repair technique has stopped the spread of the cracks and prevented the reduction in lateral capacity. Besides, the third specimen, which is identical to the URM wall but it is strengthened by PP bands, was tested and developed a superior performance in terms of changing the failure mode and also increasing the maximum strength, the strength at maximum displacement and maximum displacement by 88%, 38% and 185%, respectively, compared to URM wall.

This study introduces a new evolutionary approach called binary genetic programming (BGP) to design and assess public transportation systems from a sustainable development perspective. The BGP combines evolutionary system identification techniques with k-fold cross-validation to obtain an accurate model between the land use and transportation parameters from a sustainable urban development point of view. To assess the new model, two public transportation systems including the new tram line of Antalya (Turkey) and the bus rapid transit line of Bhopal (India) were considered. The model was applied to classify the transportation systems into transit-oriented development (TOD) and non-TOD. The solutions generated by the new model were compared with those of classic decision tree (DT) as well as the state-of-the-art random forest (RF) models evolved as the benchmarks in this study. The results showed that the BGP is highly efficient and may provide less than 5% classification error. It is superior to the DT and RF solutions, which typically require higher datasets to avoid overfitting. Furthermore, the explicit formulation of BGP in combination with the multicriteria evaluation method increases human insight on the factors affecting the design of public transportations from a sustainable urban development point of view.