نشریه آنالیز سازه - زلزله
سال پانزدهم شماره 1 (بهار 1397)

Lightweight steel structures (LSFs), which are manufactured dry and manufactured using industrial production and cold rolling (CFS). For carrying the side loads in cold-rolled structures, belt braces or shear walls are used. . Considering that the weight of the materials, the preparation and implementation of the wall is a limiting factor for its use in the repair of the frames. Determining the proper makeup that reduces the use of wall panels can be a significant factor in improving the performance of the frames in improving and framing the frames. The sample of the laboratory chosen to examine the performance of the LSF lightweight steel frame system and the accuracy of the modeling in the ABAQUS software includes a LSF light steel frame system, tested by Bin Liu et al. (2016). For this purpose, the frame reinforced samples were categorized in three general categories, including a non-reinforced sample, a braided braid, a double-row braid, and a 45-degree reinforced sample under a monotonic loading, comparing the results obtained from the sample analysis With non-reinforced specimens, it was found that the bearing capacity of the reinforced frame with double-row double-row multi-row bricks was close to the full 45-degree frame. Use of higher yielding steel increased the static strength and earth-impact resistance of the bracing, but the ability The energy absorption reduces it. Use of 45 ° steel sheets adds an extra Its shape is framed.

HSC has great mechanical properties and durability and is one of technology developments in concrete. This type of concrete has high cohesion, compressive strength and low water to cement ratio and permeability which results to high durability. HSC is a cemental composite product that contains optimum amount of fines and with a water to cement ratio (W/C) less than 0.25.High performance concrete compared with normal concrete has a structure with discontinous pores that results to high performance and minimum water permeation to concrete. HSC’s admixture contains water, silica fume, cement, fine sand, super plastisizer and rock powder like quartz that in this study are used of Iran’s local materials. In this study 10x10x10 cube specimens were made and evaluated. Compressive leads to failure were applied to concrete specimens. The purpose of this study is investigation of quartz powders increase in HSC.Results shows that concrete compressive strength with 11% quartz powder is the highest and increase in quartz powder lead to brittle pre failure and explossive failure of concrete specimens.Other considerations shows that increase of quartz powder leads to more crack on concrete and it is suggested to use fibers to prevent more crack in this type of concretes.

According to the fact that our country is located in one of the seismic zones of the world, the possibility of strong earthquakes in different regions is inevitable. Over the past years, researchers have proposed different systems for absorbing and dissipating earthquake energy in structures, which, in this regard, unrestrained buckling braces have been focused by engineers. The purpose of this research is to examine the behavior of short link beam in steel frames with buckling and non-buckling braces. For this purpose, three structures, 3, 6 and 9 stories with buckling and non-buckling braces are designed according to valid regulations and all seismic rules have also been controlled. Then, their lateral two-dimensional frame is modeled with eccentric braces on the SeismoStruct 2016 software. In order to investigate the behavior of the link beam, nonlinear static and time history analysis have been used for three far-field earthquakes and type 2 soil. In the following, the results of the shear force and the bending moment of the link beam and the nonlinear static analysis curves of the frames in two models with buckling and non-buckling braces are compared. The results of nonlinear static analysis show that the moment and shear in the non-buckling link beam can be up to 38 and 50 percent more than the frame with buckling braces, respectively. Non-linear time history analysis shows a higher growth of link beam forces in a frame with non-buckling braces than nonlinear static analysis.

Liquefaction is one of the most common ground deformation effects of earthquakes often a major cause of damage and destruction to buildings and infrastructures. The area on the study (Chalus and Nowshahr region) is located on the coastal strip of Caspian Sea, on the loose alluvial material which has been hit by numerous earthquakes throughout history. In this study, the shear wave velocity (Vs) method has been used with five experimental relationships to evaluate the soil liquefaction potential of Chalus and Nowshahr region under the assumption of non-cementation and cementation conditions. Due to the distribution of boreholes evaluated in the sediment section of the area which is less than 10,000 years old, solutions with noncemented conditions are acceptable. Analyses have shown that among 46 borehole loops, 35 boreholes are prone to liquefaction, which most of them are located in the region of Nowshahr. Considering the values of the liquefaction potential index obtained, based on the shear wave velocity method, in non-cementation conditions, 8.7% of area is PL = 0, 15.2%, in the range of 5> PL> 0, 41.3% in the range of 15> PL> 5 and 34.8% in the range of 15< PL. Due to the fact that the surface depth is an important parameter in soil lubricity, and the high level of the station, considering the high potential of seismicity of the area as well, the likelihood of liquefaction increases.

Previous studies has shown that reinforced self-compacting concrete with fiber is more suitable for structural performance. The purpose of this study was to evaluate the effects of Metkaolin and alkali resistant glass fibers on the performance of self-compacting concrete. In this study, the rheological properties (L-Box, Slump flow, T50) and mechanical properties (compressive strength, tensile and flexural strength), and durability (chloride ion penetration and water absorption) have been investigated. The results of the experiments showed that by increasing the amount of fiber, the concrete performance decreases. It was also found that the glass fiber had no positive effect on the compressive strength of the concrete. The tensile and flexural strength of self-compacting reinforced concrete increases with increasing fiber content. Durability studies have shown that the presence of glass fiber initially increases the resistance to chloride ion penetration and then reduces it, and also increases the gradual absorption of concrete water. The results of the experiments showed that the simultaneous presence of Metkaolin and glass fibers with optimal percentages can significantly improve the mechanical properties and durability of self-compacting concrete.

After use new materials for use in construction, the invention of various structural forms can be considered as the most important factor in the feasibility of the construction of high-rise structures. The structural form of the building system is a system that tolerates the various combinations of horizontal and vertical loads. The structure is taller and thinner the structural factors of the degree are more important and subsequently the need to choose the structural form is further increased [1]. In this regard, recently, in the design of high-rise structures, a new idea, the tube in tube system, has been presented by Fazlorkhan and Milestone, which has been used in many of the world's tallest structures, including the Oil Standard Building in Chicago and the World Trade Center building in New York. Therefore, in this research, by modeling a concrete structure with a height of 108 m and 28 floors (a basement floor) and adding shear walls to this system and applying different layouts for them, by SAP2000, the seismic performance of the structure under 7 accelerates has been investigated and the base cutting and displacement force of the roof is compared under different modes. The results show that as the location of the shear walls moves from the center of the structure to the outer layer, the seismic response of the high-order structure with the tube in tube system will be improved and the sections can be reduced for the cost-effectiveness of the project.

The columns, beam and roof make up the most important members of a building, each of which plays a role in the stability of the structure. These members can be made of different materials that can vary depending on the conditions and type of use of the structure. One of these materials is concrete that is mostly armed by an armature. One of the major drawbacks of using reinforced concrete is to increase the weight of the structure, and most of the efforts to optimize the structure have been made in order to stretch the members. In recent years, studies have been carried out to light concrete structures, most of which are related to roof styling, which has led to the provision of ceilings that, in addition to maintaining high resistance, significantly lower dead loads than Traditional roofs. Reducing the dead load of the roof has significant benefits to the entire structure, the most important of which is to reduce the earthquake force on the structure, which in turn reduces the sections and reduces the dead load of the structure. One of the roof systems is doublesided hollow ceilings or double-sided bubble slabs. To verify the accuracy of the numerical results, the laboratory test was verified and after checking the results, a numerical sample was considered. In this study, a 12-sample numerical model with Abaqus software was compared to compare the Cobiax roofs with steel deck roofs and concrete slabs. The results obtained in this way is no reduction in the number of spheres is about 1,12 percent more cargo capacity. The importance of this value compared to weight loss roof with a 30% reduction in the number of spheres is negligible and can use the sample with a reduced amount of 30% of the balls due to the reduced weight of the structures and effects of the structural elements justify. Also, on average, in all specimens, the specimens after the elastic region and the beginning of cracking, the stiffener of the concrete decreased, and with the increase in displacement, the bearing capacity was almost constant. In the end, the Cobiax roofs, without reducing the number of balloons, have a higher load capacity and hardness than the other two models, with the increase in force, the area under the charts of this model has increased and depreciation is more energy than other specimens.