_1676737423 20230218195343000 CMV Verlag khoffman@cmv-verlag.com Dr. Morteza Jamshidi Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 10 10 2022 4 2 Study of the collapse of Sardabroud-Chalous truss bridge Morteza Jamshidi Teymour Sam Many of the old bridges in northern Iran, which are often more than 50 years old, are made of steel trusses. The superstructure of these bridges usually consists of two simple and parallel trusses that increase lateral stability, the upper part of these two trusses are connected using bracing elements. In some truss bridges such as the Sardabroud-Chalous bridge, the transverse brace has been removed due to the small length of the span (about 31 meters). These types of trusses that do not have transverse restraints in the upper part are called pony trusses, which have less lateral resistance due to the removal of transverse restraints. On December 25, 2009, while the trailer was passing, a steel cargo weighing about 10 tons was released from the trailer floor and thrown towards one of the vertical elements of the truss. The impact of this heavy object causes the failure of this member and the subsequent failure of the adjacent members, which eventually leads to the collapse of the entire structure. In this paper, the progressive failure mechanism of Sardabrood Bridge will be studied using ABAQUS software. The results of sensitivity analysis and Downstream analysis show that except for zero force elements, other vertical and oblique elements have significant sensitivity that should be prevented from being damaged. Interestingly, at the moment of failure and after the failure, the alternative route is the force distribution, which is mainly the forces trying to cross the pressure rim, but small deformations in a chain led to large deformations and caused the progressive failure, which destroyed the bridge in 0.7 seconds. 10 22 2022 46 51 https://creativecommons.org/licenses/by-nc-nd/4.0 10.52547/JCER.4.2.46 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/58 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/58/57 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/58/57 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 10 10 2022 4 2 The effect of steel and hybrid fibers on the impact resistance of concrete enclosed with FRP sheets Zahed Parvinnejad Due to the widespread use of concrete in all kinds of structures, the probability of its exposure to dynamic loads has increased. Since concrete is one of the most widely used materials in civil engineering, its main weakness can be pointed out, which is its brittleness and brittle performance. The use of fibers to improve the properties of concrete has been the focus of engineers for a long time. The most common fibers used to increase the impact resistance of concrete, steel and polypropylene were investigated in this research as single and hybrid fibers. In this study, by using the ACI 544-based weight projection method, the resistance of concrete against impact loading on standard cylindrical concrete samples (30 x 15) containing steel fibers and polypropylene in two cases with and without lap sheet FRPs were investigated. The results showed that the use of these fibers increases the impact resistance of concrete. Also, both CFRP and GFRP sheets that were tested improve the impact resistance of concrete and increase the number of cycles of this test. Some GFRP sheets have performed better than CFRP. Also, the presence of FRP sheets has caused a change in the type of failure compared to the absence of FRP. Also, concrete samples whith fiber delay concrete breaking, significantly. 10 22 2022 41 45 https://creativecommons.org/licenses/by-nc-nd/4.0 10.52547/JCER.4.2.41 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/57 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/57/56 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/57/56 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 10 10 2022 4 2 Pervious concrete as environmentally friendly materials-an overview Shahriar Gholamin Pervious concrete contains a mixture of water, cement, coarse aggregates and little or no fine aggregates. Pervious concrete is increasingly known as an environmentally friendly material due to its usefulness in improving water quality by removing all suspended solid particles in the flood, reducing the flow of flood water, reducing the heat island effect and other environmental benefits. In this article, the results of valid research on the physical (slump, density, porosity, water permeability) and mechanical (compressive strength, flexural strength, splitting tensile strength) properties of Pervious concrete have been briefed and reported. 10 22 2022 34 40 https://creativecommons.org/licenses/by-nc-nd/4.0 10.52547/JCER.4.2.34 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/56 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/56/55 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/56/55 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 10 10 2022 4 2 Study on the Performance of High-Strength Steel Shear Wall with Opening and Pre-crack Mohammad komeil Sadeghi golafshani The use of steel shear wall in engineering construction, including high-rise building projects that bear high lateralforces, is of great importance and practical. Since the steel shear wall with opening may have some pre-cracksdue to initial damage and cause the weak lateral behavior of the shear wall, in this study, the simultaneous impactof pre-crack and opening in the three-story and one-span frame with steel shear wall has been evaluated. In thisstudy, 48 numerical samples have been studied using the finite element method and Abaqus software. Axial andlateral loading has been applied to the samples, and the parameters of the pre-crack position, pre-crack length andthe type of shear wall steel sheet material have been investigated. The results of this study demonstrated that thenumerical model made for the shear wall provides reliable answers compared to the laboratory model. In theshear walls under study, the parameter of crack length and crack position has a high impact on the ductilitycapacity, while it has little impact on the hardness and strength index. The most critical pre-crack modes in thehorizontal position, located at the top or bottom corner of the frame, have had a great impact on the lateralbehavior and reduced ductility by 60% and wall strength by 32%. On the other hand, by changing the materials ofthe shear wall steel sheet from LYP steel to St37 and St52, the final strength and hardness have increased by 3.63and 1.45 times, respectively and the ductility has decreased by30%. 10 22 2022 22 33 https://creativecommons.org/licenses/by-nc-nd/4.0 10.52547/JCER.4.2.22 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/55 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/55/54 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/55/54 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 10 10 2022 4 2 Experimental evaluation of compressive, tensile strength and impact test in blast furnace slag based geopolymer concrete, under high temperature Mohammadhossein Mansourghanaei Morteza Biklaryan Today, the use of nanoscale additives in the concrete industry with the aim of reducing the negative effects ofPortland cement and improving the mechanical properties of concrete has received much attention. Also, in orderto reduce the harmful environmental effects and increase the mechanical properties and durability of concrete,particles with high pozzolanic properties are used as a suitable alternative to ordinary cement in concrete. In thisregard, geopolymer concrete using materials containing aluminosilicate materials with adhesive properties andfiller, as an alternative to cement, has attracted the attention of researchers. Concrete resistance to high heat is ofparticular importance. Geopolymer concrete has a good performance against heat due to its strong structure. Inthe current study, slag-based geopolymer concrete was used with 0-2% polyolefin fibers and 0-8% nano-silica toimprove its structure. After curing the specimens under dry conditions at a temperature of 60°C in an oven, theywere subjected to Compressive strength, Tensile strength, and Drop weight hammer tests to evaluate theirmechanical properties. all tests were performed at 90 days of age under ambient temperature (20 ℃) and hightemperature (500 ℃). The addition of nano-silica enhanced the whole properties of the slag-based geopolymerconcrete. Addition of up to 8% nanosilica to the geopolymer concrete composition at 20% temperature improvedthe compressive strength test results up to 21.94%, tensile strength up to 15.19% and impact energy up to36.36%. Addition of up to 2% of polyolefin fibers to the geopolymer concrete composition improved the tensilestrength up to 11.76%, the impact energy up to 8.26 times and the compressive strength drop up to 22.49%.Applying high heat to geopolymer concrete samples reduced the compressive strength up to 16%, tensile strengthup to 21% and impact energy up to 72.72%. The effect of heat on the drop in results in control concrete is morethan geopolymer concrete. In the following, by conducting the SEM test, a microstructure investigation wascarried out on the concrete samples. In addition to their overlapping with each other, the results indicate thegeopolymer concrete superiority over the regular concrete. Besides, it demonstrated the positive influence ofnano-silica addition on the concert microstructure. 10 22 2022 12 21 https://creativecommons.org/licenses/by-nc-nd/4.0 10.52547/JCER.4.2.12 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/54 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/54/53 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/54/53 Journal of Civil Engineering Researchers jcer 2538-516X 2538-516X 10 10 2022 4 2 Investigation of the effect of offshore fixed wind turbine blades on fatigue damage of bases in the Hengam region in Iran Yeganeh Jahandar Saleh Aminyavari Akbar Shahidzadeh Arabani Today, wind energy is considered as one of the most used types of renewable energy for electricity production. Over the pasttwo decades, wind energy has been a major source of electricity, and electricity supply has been drastically increasing. Amongthe technologies available to generate electricity from wind, wind turbines play a major role, with offshore wind turbinesplaying a significant part. Offshore structures such as wind turbines, unlike other types of structures, are in a dynamicenvironment, the main forces generating this dynamic wave and wind environment, which impose significant structuralvibrations, fatigue loads and significant loads on the blades, the turbine, structural platform, and other components import it.Welded joints and points in offshore structures are vulnerable to fatigue failure due to stress concentrations and intermittentenvironmental loading. Offshore structures have been exposed to shock forces and cyclic loads throughout their lifetimes,which cause the cyclic loads to cause fatigue in the joints. The dynamic forces of the waves gradually cause small cracks inthe structural joints over time, and the expansion of these cracks at the weld foot and joints of the structural members reducesthe overall stiffness of the joint and in some cases even removes the member from the location of connection. Much researchhas been done on the use of offshore wind energy, but despite the special attention of the worldwide scientific community onoffshore wind energy extraction, there are still few studies domestically. Considering the water levels in the south of Iran andthe platforms in the area will add to the importance of this study. The turbine structure will be examined to perform theresearch by using and inspiring DNV and API by-laws when the method is nonlinear. The case study will also cover the Straitof Hormuz and the time zone. This research is carried out using coding in Matlab as well as analysis in Bentley SACS finiteelement software which is dedicated to the design of offshore steel structures. The results indicate that the presence of theturbine blade geometry has a significant effect on the fatigue life of the retaining structure and the entire structure. 10 22 2022 1 11 https://creativecommons.org/licenses/by-nc-nd/4.0 10.52547/JCER.4.2.1 https://www.journals-researchers.com/ojs/index.php/jcer/article/view/53 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/53/52 https://www.journals-researchers.com/ojs/index.php/jcer/article/download/53/52