mohammadhadi alizadeh elizei

Nowadays, according to the performance of prefabricated friction dampers, which are expanding rapidly, they can increase the resistance of structural systems against earthquakes and depreciate the energies created by earthquakes in the structure. To control the vibrations of the structure at one level, it is very important to use passive control systems. But in the design at different levels, they cannot depreciate the incoming energy from the earthquake. Friction dampers focus on displacement variable and are mostly used in steel structures.The friction damper works according to the rules of a Coulomb damper or a friction brake that converts kinetic energy into heat through friction. In this article, a new type of friction damper called a flat cylindrical friction damper has been designed using brake pads in the diagonal brace, and the performance and seismic resistance of this system as well as the amount of energy loss have been investigated. The configuration of the damper is designed in such a way that grooved bolt connections and twin steel cables of different sizes and thicknesses are used.And the way the internal and external components are placed in the damper is such that innovation in tension and pressure has been created.Also, the movement of the cylindrical element in the damper has increased the amount of friction due to the presence of two types of brake pads with friction coefficients of 0.11 and 0.16 and bolt connections.  It shows the performance of the damper by different sliding force at different friction levels. Geometric dimensions, thickness of brake pad, number of bolts, size of bolts, diameter of cables, sliding force, location of damper are among the variables investigated in this article. The role of brake pads, steel cables and bolt connections is very important and economically very affordable. The seismic performance of the intended frame has been investigated by 80 different modeling of the damper and the placement of the research variables. The desired optimal models were modeled in Abaqus software and analyzed and designed. The aim of this system is to reduce the relative horizontal displacement of floors and increase the amount of energy absorption. The increase in the axial force created in multiple loading cycles has always caused damage to the damper components and frames. In this article, it has been tried to use a special multi-level geometry that, in addition to reducing the axial force created in the damper, reduces the relative displacement of the frame, damages in the elements and increases the ductility.The results show that the friction surfaces of steel plates and brake pads is very high due to the displacement and damping of the cables And with the consumption of energy and its absorption by the damper in cyclic loads, displacement control is easily done. It also shows the seismic response of structures in terms of frame and damper displacement, base shear forces, energy absorption. Numerical study confirms the intended damper as an independent seismic resistant member in critical building structures when high seismic performance or seismic resilience in moderate and strong earthquakes is desirable.

Tires and waste glass are long-lasting pollutants in nature. One of the ways to recycle waste glass and rubber is to use it in concrete, which will result in minimal extraction of natural minerals. Many engineering structures are exposed to fire hazards, and therefore it is necessary to know the mechanical properties of concrete materials at high temperatures. In this research, waste glass and rubber were used as a substitute for a part of natural fine grain (sand). The size of glass particles is between 0.2-0.85 mm and with percentages of 5%, 10% and 15% and the size of rubber particles is between 3-5 mm by volume and with percentages of 5% and 10%, replacying fine aggregates. In total, 12 mixing plans were made, and from each mixing plan, 3 cubic and cylindrical specimens were made with different percentages of glass and rubber. The compressive and tensile strength, workability, weight loss, ratio of residual compressive and tensile strength of the specimens were measured at ambient temperature and at 600 °C and the average values were evaluated. In terms of appearance, after applying heat, the color of the specimens became darker and hairline cracks were widely visible on the concrete surfaces. As expected, with increasing the rubber, the compressive strength of the speciemns decreased. After applying heat, the resistance drop of all specimens was higher than the ambient temperature state. With the increase in the rubber, the resistance decreased more, which can be attributed to the burning and destruction of rubber particles and the appearance of small holes and porosity in concrete. With increasing glass percentage, the trend of compressive strength was slightly improved. The results showed that the combined design of 5% glass and 5% rubber is the optimal design and has a more appropriate performance than other designs.

This study delves into seismic design nuances of a three-span bridge, particularly focusing on the often neglected vertical earthquake forces in concrete bridge codes. Investigating disparities in deck length and the intricacies of soil-structure interaction (SSI), it evaluates their influence on variations in longitudinal displacement. By analyzing three distinct near-field ground motions, substantial shifts exceeding 50% in column axial demands are observed, subsequently affecting pier demands and mid-deck moments. To address these findings, coefficients are proposed to effectively incorporate vertical seismic forces into bridge design, thereby enhancing structural safety and integrity. This research underscores the critical importance of seismic considerations in optimizing bridge engineering practices. Through a comprehensive examination of bridge responses to seismic forces, it aims to bolster structural resilience and safety in critical infrastructure investments. By scrutinizing seismic intricacies in bridge design and construction, this study emphasizes the imperative role of understanding seismic dynamics to ensure robustness against seismic events, ultimately contributing to the advancement of bridge engineering standards and practices.

The energy consumption of a residential building is considered in terms of energy use and efficiency. Therefore, forecasting the energy consumption of buildings has been raised as a challenge in recent decades. In a residential home, electricity consumption can have recognizable patterns daily, monthly, or yearly depending on living conditions and daily habits and events. In this research, artificial neural network (ANN) and adaptive fuzzy-neural inference system (ANFIS) have been performed using MATLAB software to predict building energy consumption. Also, random data collected based on the criteria obtained from the hourly electricity consumption of conventional residential buildings in Tehran has been used. In order to evaluate and measure the performance of this model, statistical indicators have been used. According to the applied settings (type of learning, number of steps, and error tolerance), the system error rate is calculated based on MSE, RMSE, μ, σ, and R statistical indicators and the results of energy consumption forecast in three buildings with high accuracy and correlation coefficient. R is more than 98%. The output of this research is an intelligent combined system of ANN and ANFIS. The obtained values well show the ability of this model to estimate energy consumption in the mentioned buildings with high accuracy.

With the advancement of technology in the world, industrial waste has become one of the most important environmental challenges. Deformation and reuse of these wastes is one of the ways to improve the sustainable state of the environment. Glass and rubber are among the most widely used materials in the world, which due to their nature have a lot of wastes. Waste tires cause a lot of environmental pollution due to their non-degradable materials. The use of waste glass and rubber in the construction industry can be a good solution in reusing waste materials. Concrete, on the other hand, is one of the most widely used materials in the construction industry, and the addition of rubber and glass crumb to concrete can improve some of its mechanical and dynamic properties. Of course, heat resistance of materials is one of the features that is effective in the type of application. Adding waste rubber and glass to concrete, of course, depending on their amount and size can increase the heat resistance of concrete to some extent.
In this research, the effect of replacing small and large aggregates with rubber and also glass powder with cement in concrete at ambient temperature and high temperature has been studied. The size of rubber used in concrete in two categories is 1 to 3 mm and 5 to 10 mm, which are replaced by fine-grained and coarse-grained, respectively, with replacement values ​​of 0, 5 and 10%. The size of the glass used is smaller than 75 microns and it can be replaced with cement with 0, 10, 15 and 20% replacement values. Shredded truck tires and powdered construction glass were used. In this study, cubic specimens were made into 15 x 15 x 15 cm specimens and cylindrical specimens with a diameter of 15 cm and a height of 30 cm were made according to the standards and processed for 28 days in optimal conditions. After processing, the number of cubic and cylindrical specimens was subjected to compressive and tensile tests. A number of other samples were placed in an electric furnace and heated to 600 ° C as standard. After removing the samples from the furnace, they were naturally placed at room temperature for 24 hours and then they were tested for the Residual compressive and tensile strength. The microstructure of concrete containing glass and rubber was examined by scanning electron microscope (SEM). The results of this study showed that adding rubber and glass to concrete causes a decreases compressive strength and increases tensile strength. The D10C10 design, which has the highest compressive strength, has a resistance reduction of about 12% compared to the reference design. The highest tensile strength of heated samples is related to D5C15 design, which is about 43% higher than the heated reference design. By comparing the sum of heated and unheated samples, it can be seen that heat at 600 ° C has reduced the compressive strength by an average of about 33%. In general, concrete made with 10% replacement of rubber instead of coarse in unheated samples and 15% glass instead of cement in heated samples showed better properties. Also, in the study of concrete microstructure, adhesion between rubber and concrete was appropriate.

One of the recycling approaches for waste materials like tires and glass is to use them in concrete. In this paper, the effect of the simultaneous use of waste rubber as partial substitution of fine aggregate and glass powder as partial substitution of cement, on workability and mechanical properties, in ambient temperature and after exposure to temperature of 600 °C, is investigated. In order to evaluate the effect of rubber particle size on workability and mechanical properties, two different rubber particle sizes of 0.15-1mm and 3-5mm were used. In total, 13 mixtures were prepared. Except for the reference mixture, the rest contained a combination of rubber particles replacing fine aggregate with the percentages of 5% and 10% by volume and glass powder replacing cement with percentages of 10%, 15% and 20%. First of all, the slump test was carried out. Moreover, compressive strength and tensile strength, before and after thermal exposure, were investigated. In order to have an understanding of waste material's behavior, scanning electron microscopy and energy-dispersive X-ray spectroscopy tests were conducted. the results indicated that 5% for rubber particles, 10% for glass powder and also rubber particle size of 3-5 mm presented the best results among mixtures containing rubber and glass powder, in terms of compressive and tensile strengths.

In this paper, parametric studies were performed on some pipes buried in soil under blast loadings. The effects of various parameters, such as the physical properties of liquid, air, soil, pipe, and T.N.T were investigated. The Arbitrary Lagrangian-Eulerian (ALE) method was used in the LS-DYNA software. In the following, a compared between liquids. The results show that, the pipe has undergone increased pressure and stress by reducing the fluid density. Also,This indicates that the higher the fluid density is, the less pressure and stress will be impose d on the pipe and vice versa. In general, the result demonstrates that a higher density of soil causes higher pressure and stress transfers on the pipe and explosion in lower soil density result in less damage to the pipe and acts as a damper under waves of explosion. In other words, higher density in the soil causes more pressure and stress transfers on the pipe and lower soil density acts as a damper under the waves of explosion. Now, knowing the soil type performance on the stress and pressure transfers in the buried pipes under explosion, it can be realized that pipes with high resistance should be used in soils with high density due to the transmission of high stress and pressure through the pipes considering the fact that buried pipelines, while in soils with lower density, pipes with lower resistance can be applied due to better soil performance like a damper and transmission of less stress and pressure through them. Therefore, with the correct selection of pipes in terms of resistance according to the regional soil type, a substantial sum can be economically saved for the implementation of oil and gas pipeline projects.