نشریه مهندسی سازه و ساخت
سال دهم شماره 9 (پیاپی 74، آذر 1402)

Monitoring structural health is very important to maintain the useful life of civil structures. Many monitoring methods have been developed to provide practical tools for early warning against structural damage or any type of anomaly. Therefore, the health monitoring method of the structure is considered the main approach for the management of identification and diagnosis of damage in different areas. The need to monitor the behavior of the structure is increasing every day, but due to the development of new materials and more complex structures, this leads to the development of strong and sensitive methods for the health monitoring of the structure. Artificial intelligence is an efficient alternative approach to classical modeling methods. Solutions based on artificial intelligence are good alternatives for determining engineering design parameters when testing is not possible; Therefore, it leads to a significant saving of human time and effort in experiments. Today, machine learning has become the most successful sub-branch of artificial intelligence. Identifying damage using intelligent signal processing and optimization algorithms based on vibration criteria is one of the important things. Some recent studies on the applications of artificial neural networks for damage and crack detection have been reviewed in this paper. An attempt has been made to provide a comprehensive review of the published articles in the field of application of optimization methods and inverse methods, artificial intelligence and machine learning, and assessment of damage and cracks in various structures using artificial neural networks, with a view, especially on the studies conducted in the past decades.

Due to expansion of population and construction, also due to lack of space, weakness of ability to respond to the traditional method, the need to introduce and investigate the industry in the building is more evident. For this reason, due to the ineffectiveness of traditional systems in mass production, it seems necessary to pay attention to the industrial methods of building production. For decades, plans for the industrialization of building production have been started in the country, but they have not been successful because by importing a few manufacturing plants that are largely dependent on industrialized countries in terms of technology and there are no regulations and technical knowledge corresponding to it in the country, it is not possible to Industrialization goals achieved. Industrialization should begin with a careful examination of the world's leading technologies and ensure the possibility of responding to cultural, environmental and climatic needs, as well as its ability to adapt to the construction patterns in the country and continue with cultivation to strengthen this technology. In this research, firstly, by conducting library studies, a list of effective factors in increasing the stability of launching industrial construction projects was prepared, and through questionnaires based on the Likert scale, the opinions of experts in the field of industrialization of construction in Kerman city were collected, and after checking validity and reliability of the questionnaire, The grouping of factors was done using specific assumptions, according to the results, then the decision matrix was made based on indicators and options, the formation and classification of points in fuzzy intervals was done, finally, using the weighted least squares method and Yager method, the importance coefficient of the indicators according to Base on the findings of the research, "economic", "social and political", "management", "qualitative" and "environmental" indicators have the highest impact respectively.

The main purpose of this article is to evaluate and prioritize some factors related to the delay in the completion of the Mehr housing project in Kermanshah province. The research method is a survey which, in terms of the objective dimension, is applied to the statistical population including all technical experts of departments and managers of planning and executive bodies of Kermanshah province related to the Mehr housing project with the number of 365 people, which using Cochran's sampling formula, the volume A sample of 187 people was determined. A researcher-made questionnaire was used to collect information. The analysis of the results of the Friedman ranking test showed that at the error level of 0.05, the ranking of the factors affecting the delay in the completion of the Mehr Kermanshah housing construction project is significant from the point of view of the research sample, and the research sample has different ratings of the factors affecting the delay, so that The factor of project costs and expenses with an average of 4.30 has the highest amount and the factor of weakness in project implementation with an average of 2.35 has the lowest amount. Also, the comparison of the average ratings of the factors affecting the delay in the completion of the Mehr Kermanshah housing construction project showed that the highest average rating (8.40) is assigned to the factor of project costs and expenses in grading. From the point of view of policy making and considering that all these factors can be included in the group of management factors, it is necessary to review the management team to reduce the delay in the completion of the Mehr housing project.

Today, the use of pits in construction projects is increasing due to the maximum use of land and also the high price of land. The use of methods to maintain stability, security, time and cost has always been a concern of employers and those involved in excavation projects. Value engineering is a way to achieve the optimal state in carrying out construction projects, which is effective in reducing project time by eliminating additional costs as well as ineffective activities without affecting the process and operation of the project. Due to the importance of two issues in this research, an attempt has been made to investigate the factors affecting excavation projects by adopting a value engineering approach. In this research, the staticity of the pits based on truss, concrete pile, nailing and anchor methods as well as the use of soil rupture wedge as an innovative method for stabilizing shallow, semi-deep and deep pits have been investigated. The results are evaluated in terms of cost, time, pit security and occupied space and are evaluated and weighted using Analytic Hierarchy Process (AHP). The results show that the use of wedge rupture method in shallow excavations can be a good option in terms of value engineering. Also, using concrete pile method for semi-deep pits and using anchorage method for deep pits according to the results are considered suitable options.

One of the early deterioration factors of reinforced concrete structures is the corrosion of its steels, and in structures with greater sensitivity, such as prestressed structures, where steel elements, including prestressed tendons, play a much larger role in supporting the structure, the importance of this issue increases. In this research, an experimental evaluation of the flexural behavior of prestressed concrete beams under the influence of corrosion. To this end, four prestressed concrete beams with a rectangular cross-section (150 mm × 300 mm) and a length of 2 m were fabricated. The method for causing corrosion in specimens was accelerated by using constant electric current in prestressing tendons and in a pool containing 5% sodium chloride electrolyte solution. One prestressed concrete beam without corrosion was considered as a control specimen, and in the other three studied beams, corrosion occurred at three levels of 5, 10 and 15%. After exposure corrosion, the specimens were subjected to four-point bending test in order to check the structural behavior. The results indicated that the corrosion created at different levels reduced the bearing capacity and other behavioral characteristics of the specimen under study, including the amount of energy absorption, effective hardness and midspan displacement. Increase of the corrosion level, increases the decreasing trend of the studied parameters. At the highest level of corrosion (15% level), the values of the parameters of bearing capacity, absorbed energy, effective hardness, and mid-span deflection decreased by 24%, 34%, 37%, and 19%, respectively. Also, the investigations showed that there is a non-uniform distribution of corrosion caused by the accelerated method along the prestressing cables and difference between the actual and calculated corrosion rates based on the Faraday's law.

The purpose of this research is to conduct a laboratory study to investigate the effect of using microsilica additive on the compressive strength of concrete under different durations of accelerated steam curing. For this aim, four mix designs have been considered, in which in two of them microsilica additive is used in the amount of 10% and 15% by weight of cement. 48 cubic samples were cured by immersion in water and their compressive strength was measured at the ages of 3, 7, 14, and 28 days. Also, 84 cubic samples were subjected to accelerated steam curing under the maximum temperature of 66±2 ºC and their compressive strength was measured after 4, 8, 16, 24, 32, 40, and 48 hours of treatment. The research results show that by adding microsilica to concrete, the ultimate compressive strength increases in both types of curing. Calculating the ratio of the strength of the samples under steam curing to the corresponding value in water curing indicates that the designs with microsilica have weaker performance than the designs without microsilica in terms of gain rate in compressive strength. Also, the results show that with the reduction of the water-cement ratio, concrete strength setting in steam curing occurs faster. Finally, it is suggested that if microsilica powder is used in concrete as an additive, in order to provide 70% of the 28-day strength of concrete, which is necessary for producing prefabricated and prestressed concrete, microsilica powder must be used in the amount of 15% by weight of cement and concrete must be subjected to steam treatment for 24 hours.

The Architecture, Engineering, Construction, and Operations (AECO) sector is adopting Building Information Modeling (BIM) in public and private organizations worldwide. The public sector plays an essential role in inducing and encouraging the implementation of BIM in the industry. However, there is a lack of comprehensive and integrated research on the critical factors for enterprise-scale BIM adoption in government agencies. The primary purpose of this study is to provide a framework to analyze the critical success factors (CSFs) of BIM implementation in Iranian government organizations. This method includes a comprehensive literature review, an exploratory study in three Iranian government institutions, and a survey conducted with 68 Iranian experts involved in admissions to public organizations. The methods used to analyze the factors are Interpretive Structural Modeling (ISM) and the DEMATEL method used to analyze the relationships and interactions between the factors quantitatively. The results include the proposal of sixteen CSFs and a model's development. Finally, the creation of a framework for adopting BIM by government agencies according to BIM contexts prioritized CSFs and levels of analysis. The main contribution of the current research is a proposed framework for BIM adoption, which includes a comprehensive and integrated approach based on a set of CSFs from Iranian government organizations and a greater understanding of contractual, regulatory, technical, procedural, and political characteristics for the public sector.

The purpose of this study is to present a new method of plate damage detection using the wavelet-based contourlet transform method. The contourlet transforms developed based on the Wavelet transform is a new two-dimensional transform that overcomes the limitations of the wavelet transform. The wavelet-based contourlet transform is a new family of contourlet transforms with the same two-step characteristic introduced from the same filter banks, radial, and angular decomposition. This method is used in plate damage detection for the first time. In the first step, the plate using the wavelet transform is decomposed into four sub-bands. Then, a radius decomposition with eight bands in each sub-band of the initial image is introduced using one of the directional filter banks. The radius decomposition in different directions is known as the advantage of this method in comparison with the wavelet transform. This advantage is observed in images with curved lines. In this method, the change in the elastic modulus is considered as damage in plates. The fundamental mode shape of intact and damaged plates is first obtained from the structural frequency analysis. Then, the location, shape, and approximate size of damage are obtained by applying this transform to the responses of the structure.

During their useful life, structures are exposed to various loads such as earthquake, impact, fire, etc. Each of these loads causes a different response in the structure and sometimes causes damage. Sometimes a structure may be exposed to successive loads. Earthquake occurrence in buildings that have been exposed to fire load is one of these loads. Changes in parameters such as material specifications, gravity loads, and geometric properties, which are sometimes that the implementation is different from the design, have an effect on the response of structures. In this research, it has been tried to use sensitivity analysis to determine the effect of changes in parameters such as modulus of elasticity and rebar's yield stress, concrete strength, concrete cover, dead and live loads and span length on the performance of a seven-story reinforced concrete frame in the scenario The earthquake happens after the fire. The intended structure is modeled in OpenSees software with mechanical-thermal properties and is first exposed to fire load introduced in EN 1991-1-2 and finally to earthquake. Tornado diagram analysis and Monte Carlo simulation have been used to perform sensitivity analysis of the mentioned variables. The results showed that applying thermal load before seismic load to the structure definitely affects the seismic behavior of the structure and reduces the resistance and increases the dynamic response of the structure. The average drift in the critical floor for the applied records, for the states without fire, one hour of fire, two hours of fire, and three hours of fire, is equal to 0.027, 0.029, 0.033, and 0.036, respectively. Dead load and concrete strength have the highest sensitivity and modulus of elasticity and span length have the lowest sensitivity in the dynamic response of the structure in the scenario of earthquake after fire.

Shear wall design is one of the optimization problems, due to the presence of various parameters and its inhomogeneity, it has always attracted the attention of researchers and structural designers. The purpose of this research is to design a shear wall and its optimal arrangement in the height of an intermediate reinforced concrete three-dimensional structure. Considering the necessity of preserving the environment and reducing the emission of greenhouse gases, which are mostly made up of carbon gas, the objective function has been formulated based on the reduction of CO2 emission caused by the materials used in the shear wall. On the other hand, in order to optimize the design, CSA meta-heuristic algorithm has been used, and to satisfy the constraints of the problem, the objective function has been used by the penalty method. Also, in order to simplify the search space, a number of shear walls have been pre-designed and discretely coded. In addition, displacement and force constraints have been applied regarding the shear wall and boundary elements so that the design and layout of the walls can be done correctly. In this research, a reinforced concrete moment-resisting frame with a shear wall in seven stories has been modeled and analyzed with the OpenSees software. Based on the optimal design of shear walls, the algorithm was successful in achieving the desired layout by satisfying all constraints.

Bridges have a special place in transportation infrastructure due to their direct connection with other places. These structures aim to carry highway traffic loads, pass any obstacle and establish effective communication between two destinations. Damages caused by earthquakes and human factors cause very serious damage to bridges, and if even the failure of a member does not cause the structure to collapse completely, the cost of retrofitting is very high. For this purpose, researchers and engineers suggested the use of structural control systems along with accurate seismic analysis to predict the behavior of the structure. The purpose of this study is to investigate the displacement in bridges using multiple tuned mass dampers in parallel and series mode. The effects of damper modeling on Meloland overpass bridge are investigated for the first time with the help of the proposed method in this article. In this research, the bridge structure presented by Vahid Shirgir et al. is used as a sample structure to investigate the issues raised with Opensees software. This bridge is designed by taking into account the regulations, gravity and dynamic loads, and its structural specifications include dimensions, type of materials used based on the article of Vahid Shirgir et al. Finally, it was found that the multiple tuned mass damper in parallel mode has a better performance in reducing the maximum displacement than other tuned mass dampers. Also, according to the results, the response of the structure equipped with multiple tuned mass dampers decreased by 21% and improved the seismic performance level of the bridge column.