_1749311428 20250607192028000 CMV Verlag khoffman@cmv-verlag.com Asst. Prof. Morteza Jamshidi Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Mansour Bagheri https://orcid.org/0000-0003-0024-1683 Seyed Abbas Hosseini https://orcid.org/0000-0001-5694-0366 In buckling restrained bracing systems, earthquake-induced elongation problems are solved, and BRB-equipped structures have a much more effective performance in energy absorption in addition to high lateral stiffness. Systems equipped with viscous dampers (VD) also have great potential to absorb seismic energy. To assess the vulnerability of structures equipped with buckling restrained bracing (BRB) and VD systems, three structures (6-, 10- and 15-story) were chosen as representatives of mid-rise, high-rise and super high-rise buildings and modeled in four states of moment-resisting frame (MRF): the frame equipped with VD, the frame equipped with BRB, and the frame equipped with BRB and viscous damper simultaneously (BRB+VD) using OpenSees-2.4.6 software under incremental dynamic analysis (IDA). Seven seismic records were applied, and the maximum inter-story drift response and fragility curves were determined. The results indicated that although the simultaneous application of BRB+VD causes a significant decline in the response of all structures, each of these two systems is able to provide structural safety at various levels in mid-rise structures. It is required to apply both systems simultaneously to provide safety for slight and moderate levels of damage in high-rise buildings, while super high-rise buildings are vulnerable to whole levels of damage, and their structural safety involves the simultaneous use of both systems. 06 01 2025 57 67 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.57 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/172 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/172/192 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/172/192 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Mohammadhossein Mansourghanaei https://orcid.org/0000-0003-4644-104X In this laboratory study, a mixed concrete design containing Portland cement type 2 with a grade of 500 kg/m3 was made. Weight loss and ultrasonic pulse velocity (UPV) tests were performed on concrete samples at a curing age of 90 days at room temperature (21 ℃) and under a temperature of 600 ℃. In order to further investigate and verify the results, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were performed on concrete samples at a curing age of 90 days. The results of the tests in this study were evaluated together and compared and analysed with the results of other researchers. Applying high heat to concrete samples caused a decrease in results. In this regard, in the weight loss test of concrete samples, the weight of the concrete sample decreased from 2378 to 2225 grams, which was a decrease of 72.6%, and in the UPV test, the speed of ultrasonic waves decreased from 6179 to 3411 m/s, which was a decrease of 79.44%. At the end of this study, the results of SEM and XRD analysis at room temperature and under high temperature, while coordinating with each other, overlapped with the results of the weight loss test and the ultrasonic wave velocity test in concrete samples. 06 01 2025 68 75 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.68 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/163 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/163/193 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/163/193 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Kouros Nekoufar https://orcid.org/0000-0002-4530-3115 Shahrzad Farrokhi https://orcid.org/0009-0006-9074-5939 Beams are always noteworthy as an engineering structure due to their wide application in industry such as bridges, railway tracks, floors and ceilings of buildings and many other cases. Therefore, considering the wide application of these materials in industry, the analysis of this category of structures becomes important in the overall design process of these parts in a structure. With the increasing use of beams in industry and the need to increase their efficiency and ensure their proper functioning, the use of new materials such as functionally graded materials[1]has increased. The use of composite materials, shape memory alloys, piezoelectric materials, etc. and the expansion of the scope of use of these materials has led to increased efforts by researchers to achieve the construction and design of structures and parts with better efficiency and quality. On the other hand, conducting experimental analyses on these materials is associated with problems such as size, price, complexity of the laboratory model, etc., hence the presentation of general theoretical models­. More suitable for ‌In this research, the vibration analysis of a nanobeam is considered. Unidirectional FGM (functional properties along the beam thickness) with carbon nanotubes and a layer‌ Metal and ceramic supports on various types of supports ‌Sometimes. ‌The solutions, including simple, complex, etc., were discussed. The solution method in question was the mixing method, and in line with the thickness of the numerical method, the differential function. It has been DQ based on this, relationships have been extracted regarding how to increase the natural frequency and the lowest natural frequency, as well as the length-to-thickness ratio, natural frequency changes, and dimensionless natural frequency changes in the beam. 06 01 2025 21 37 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.21 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/162 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/162/185 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/162/185 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Mohsen Asgharinia Nowadays, with the aging of old structures and the advancement of construction technologies, demolition projects for outdated structures have seen significant growth. this paper focuses on demolition methods in detail. In a case study conducted in Iran, this paper evaluates the demolition methods for a concrete silo using the Analytical Hierarchy Process (AHP) to select the optimal method based on cost, time, and quality (safety). Time evaluation is performed using MSP software, while cost assessment for each method is estimated based on resources allocated to the activities within the Work Breakdown Structure (WBS) of each approach. Safety evaluation employs a combined application of the AHP and Data Envelopment Analysis (DEA) methods. Required data for constructing pairwise comparison matrices were gathered through questionnaires completed by domain experts. The results reveal that the demolition method using concrete wire saws scores the highest among the methods evaluated. Furthermore, based on modeling results in Sap2000 software, it is shown that single-stage toppling of the silo by removing its main columns is not feasible. Subsequently, the site layout design and lifting plan calculations for the selected method were carried out. All outcomes were compared with real-life execution, and the project's success demonstrated the effectiveness of the chosen method due to comprehensive consideration of all construction management aspects of a demolition project. This paper is written with the aim of simplifying technical concepts in the management of demolition methods. 06 01 2025 76 98 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.76 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/160 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/160/195 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/160/195 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Sadegh Rezaei https://orcid.org/0000-0002-8745-7059 Majid Moradi https://orcid.org/0000-0002-8470-6160 Ali Hasanzadeh https://orcid.org/0000-0001-5546-0950 One of the most important topics in geotechnical earthquake engineering is the examination of site effects. This phenomenon alters the characteristics of seismic waves, leading to amplified vibrations and consequently increasing financial and human losses. Today, various methods exist for assessing site effects, among which numerical methods are among the most widely used due to their reasonable costs, reduced time, and high accuracy. In this research, a problem was subjected to the effects of three different earthquakes (Bam, Naghan, and Tabas). By comparing the results of each earthquake, the site effects were identified in terms of changes in peak gorund acceleration (PGA), frequency content, and shaking duration. Additionally, to investigate the effects of soil layering, the position of the layers was altered, revealing significant impacts of layer changes on seismic wave characteristics. Finally, to assess the effect of earthquake source type, one earthquake was evaluated at two different stations (near/far field). Results indicated a significant influence of the epicentral distance on the amplification and attenuation of waves.  06 01 2025 10 20 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.10 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/159 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/159/190 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/159/190 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Mahdi Jalali https://orcid.org/0009-0000-3570-919X Rasoul Shadnia https://orcid.org/0000-0002-3012-8473 One of the ways to dispose of urban waste is to burn it in incinerators. In this research, it was tried to use the ash obtained from the waste incineration plant of Saveh city (Iran) as a substitute for part of the consumed cement in concrete production. To achieve this goal, the effects of waste ash on compressive strength, abrasion resistance, flexural strength, water absorption and unit weight of concrete were investigated using experimental methods. The concrete used was made with a compressive strength of 30 MPa. The results obtained from the laboratory tests showed that the addition of waste ash as a partial substitute of the cement in the amounts of 10, 20, and 30% in the tested concrete samples caused to decrease the compressive strength by 21, 42, and 49%, the flexural strength by 5, 15 and 22%, and the unit weight of concrete by 3, 5 and 7% respectively, and to increase the water absorption by 3, 6 and 12% respectively, compared to the control sample. Also, there is a slight decrease in the abrasion resistance of concrete including waste ash. However, the obtained strengths were still acceptable for the construction of concretes that require less strength. On the other hand, the use of this ash as a part of the cement used in concrete not only removes the concern of waste incineration plants to dispose of this pollution, but also reduces the consumption of cement and consequently reduces greenhouse gases caused by cement production. 06 01 2025 1 9 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.1 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/157 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/157/183 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/157/183 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 06 01 2025 7 2 Hadi Faghihmaleki https://orcid.org/0000-0002-3078-4948 Seyedeh Sara Farahpour https://orcid.org/0009-0002-3228-4506 Concrete-filled double-shell circular steel columns consist of two concentric steel tubes with the space between them filled with concrete. These columns are a suitable option for high-rise construction due to their lower weight and also allow the passage of cables and utilities. In this research, modelling was carried out in Abaqus software and parametric analysis was performed based on variables such as the shape and dimensions of the stiffeners. The results show that concrete-filled double-shell columns perform better against axial and seismic loads than columns without concrete. The total and square stiffeners give the best performance, but it is not possible to increase their number due to space constraints. Trapezoidal stiffeners are also effective in improving axial and lateral performance, but result in a reduction in ductility. Circular stiffeners have the greatest reduction in ductility and their use is limited. In general, the choice of stiffener type has a significant effect on the performance of double shell columns. 06 01 2025 38 56 https://creativecommons.org/licenses/by/4.0 10.61186/JCER.7.2.38 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/154 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/154/191 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/154/191