Material selection, cross-sectional shape and dimensions of silos directly affect structural durability. For example, concrete and steel silos offer different advantages in different projects and both materials are ideal for long-lasting projects. By using advanced construction techniques in design, the construction process can be accelerated, and the strength of the structure can be increased.

Silos can be in various shapes such as square, rectangular, cylindrical, hexagonal and octagonal. Each geometric shape has its own advantages and disadvantages. These are decisions that can be evaluated according to the results of the analyses in the design.

In the next stages, factors such as storage capacity, discharge systems and material flow rates should be considered. Therefore, conical bottoms and internal structures in the silo optimize the material flow and balance the load distribution. In silo design, static, dynamic and earthquake loads must be calculated. In addition, lateral forces, moment effects and capacity ratios have a significant effect on the structural strength of the silo.

Material flow is also a critical element in silo design. Flow patterns such as mass flow and funnel flow regulate the movement of the material in the silo. Therefore, it is important to select the most appropriate flow pattern in silo design according to the requirements of the project.

Advanced techniques used in silo construction include slipform and jumpform methods:

1. Slipform Method: It creates a continuous structure with continuous pouring of concrete and is ideal for large-scale projects. This method requires 24/7 uninterrupted work and accelerates construction processes. Thanks to the slipform method, a monolithic structure is obtained, and the strength of the structure is increased.
2. Jumpform Method: It is based on the process of pouring concrete layer by layer and a certain time is allocated for each layer to dry. This method increases the integrity of the structure and ensures quality control. The jumpform method allows for detailed inspection and is particularly used in projects requiring high strength.

Silo design and construction is a process that requires expertise in engineering and structural design. Proper material selection, appropriate construction techniques and detailed structural analyses are the cornerstones of a successful silo project. Silos designed in compliance with occupational safety and environmental regulations provide long-lasting and reliable storage solutions. By considering these technical details and engineering approaches, reliable silos can be built for industrial and agricultural storage needs.

In addition, international and local standards should be taken into consideration in silo design. Standards such as ACI 313-16, ASCE 7 and Eurocode 1 are an important part of the design process to ensure the structural strength and safety of silos in structural statics and analyses.

These elements, which must be considered in silo design, are the basis for creating a successful and reliable storage solution. These technical details and advanced engineering approaches should be considered to build reliable silos for industrial and agricultural storage needs. In this way, silo storage processes can be made more efficient and safe, and long-lasting structures can be created.

In performance-based design, linear elastic calculation methods based on strength and nonlinear inelastic calculation methods based on strain and displacement are used to determine the earthquake performance of existing and retrofitted buildings.

Linear calculation methods are not sufficient because they cannot accurately model the deformations in the structure and the plasticity of the joints. Therefore, linear analyses are usually required to perform nonlinear analyses for the detailing of the retrofit design and making final decisions. However, nonlinear analyses should be used for detailing the retrofit design and making final decisions.

In the Equivalent Earthquake Method, the element stiffnesses and section properties of the structure are determined and the internal forces and displacements are calculated by linear distribution of horizontal earthquake loads and the behaviour of the structure under these loads by applying stiffness.

Nonlinear calculation methods are used to analyse the plasticity and deformation capacities of structures when they exceed elastic limits. These methods are critical for predicting the actual behaviour of structures more accurately. Nonlinear analyses help to determine the damage potential, energy absorption capacity and performance levels of structural elements.

Nonlinear calculation methods are critical for accurately assessing the earthquake performance of structures and planning retrofitting strategies. Methods such as pushover analysis and time-history analysis help to determine retrofitting requirements by examining the elastic and plastic behaviour of structures in detail.

• In the Equivalent Earthquake Method, element stiffnesses and section properties of the structure are determined and internal forces and displacements are calculated by linear distribution of horizontal earthquake loads and the behaviour of the structural elements under these loads using the stiffness matrix.
• Pushover analysis is a widely used nonlinear static analysis method to evaluate the performance of structures under earthquake effects.

In design by deformation applied in earthquake performance analysis, the capacity curve of the structural element shows the elastic and plastic behaviour of the structure and displacement is generated by horizontal load. Thus, it enables the determination of different performance levels such as immediate use, life safety, pre-collapse. As a result, it shows the damage status of the structural elements.

• Modal Combining method is a method that examines the dynamic behaviour of the structure by considering the earthquake response spectrum, natural vibration modes and frequencies according to the data obtained from the structure. Accordingly, modal analysis is performed and the whole response of the structural elements is calculated by using SRSS, CQC methods.
• Time-History Analysis is a nonlinear calculation method that examines the time-dependent behaviour of structures under the data according to real earthquake records as specified by the regulation and should be used for the evaluation of structural performance. is the most detailed analysis method.  Deformations, plastic joint formations and energy absorption capacities of the structure at different time points are analysed. The earthquake records to be used in earthquake performance analyses are selected in accordance with the seismic hazard assessments specific to the region where the structure is located. Accordingly, the moment and shear forces generated in the existing structural elements provide a detailed evaluation of the structural performance.

Destructive Methods

Coring

The coring method allows cylindrical concrete samples taken from the reinforced concrete structural element to be tested in the laboratory area to see how much strength the concrete has. Due to this process, the sampling process is carried out using hand core or water core machines so as not to cause even minor damage to the structure, and the samples obtained are tested for the compressive strength of the structural element. The year in which the structure was built provides data on the current concrete strength of the structural component.

Concrete Stripping Method

The concrete stripping method allows the concrete and plaster layer on the reinforced concrete elements to be stripped and examined by measuring the diameter, spacing, and corrosion status of the reinforcement using mechanical equipment. The method is completed by recoating the stripped layer.

Non-Destructive Methods

X-ray Method

X-ray equipment is used to non-destructively determine the location, size, quantity and arrangement of reinforcements in structural elements inside the structure. The X-ray device provides information about the reinforcement without damaging the structural element and provides information about the reinforcement class and corrosion status by analyzing the images obtained.

Concrete Test Hammer

In the concrete test hammer method, by applying a certain impact to the concrete surface and measuring the rebound value, it provides information about the surface hardness of the concrete and the existing concrete strength and reinforcement. Schmidt hammer is a good approach to understand the distribution of concrete quality in the building.

Destructive and non-destructive methods used in earthquake performance analysis are essential to assess the current condition of structures and to increase the resistance of structural elements against earthquakes. While destructive methods provide precise results on concrete and reinforcement quality, non-destructive methods provide comprehensive information without damaging the structure. By using these methods together, the earthquake performance of structures is analyzed in the most accurate way, and the data obtained enables more accurate retrofitting methods to be selected.

The correct design, material selection and construction methods should be considered for the static calculation report. That is, the safety of reinforced concrete structures depends on the correct design and construction of these elements. Therefore, by determining the problems and needs in the design of a structure, static reports should be prepared with reliable calculations. Here is a look about reinforced concrete structures and static calculation report of these structures;

– Reinforced concrete structure designs should be designed according to TBDY2018, TS500 and TS498. Therefore, the standards used should be specified in the report with details.

– External factors affecting the structure such as live, dead, wind, snow and earthquake loads acting on the carrier system should be included in the report. With load combinations, the structure should be designed with the most unfavorable scenario.

– The report should include parameters such as material properties of concrete and reinforcing steel, strength and modulus of elasticity.

– The general geometry of the structure, the structural system, physical details such as columns, beams, curtains and slabs and dimensions of reinforced concrete elements and cross-sectional analyzes are also included in the report.

– In order to make calculations in static reports, the results of the ground investigation should be examined for the bearing capacity of the soil and foundation design. Therefore, when important parameters are taken into consideration, foundation types and dimensions can be determined.

– Load combinations evaluate the situations that show the highest possible effect by combining different load types.

– Shear force and bending moment analyses should be interpreted by evaluating the forces and moments in columns, beams and other elements.

– According to the geological and topographical situation in the structure, the analysis of earthquake effects should be calculated and accordingly, measures should be taken to ensure earthquake resistance in the report by evaluating the earthquake performance.

To examine about the static calculation report of steel structures;

– The class and quality of the steel material used must be specified in the report. It is important to select the correct steel grade, especially with the specified strength and elasticity properties of the steel.

– Steel static calculation reports help engineers to determine the sizing of steel elements, stability checks, and bearing capacity. In the project of the steel structure, it includes a building design that ensures safety with documents containing the calculations of your carrier system.

– By taking details according to the plans and sections describing the structural system of the structure, it provides analysis of the effects of vertical fixed loads, moving loads, roof loads, temperature change effects, snow and wind loads, soil thrusts and other loads in the calculation report according to the loading conditions.

– Steel structures are resistant to external factors such as earthquake and wind compared to other types of structures. Static calculation reports evaluate the durability of steel structures against such effects and optimize the flexibility of structural elements.

– In the basic design of the structure, soil type, bearing coefficient parameters also have an important place in the static report.

– Relative storey drifts, second order effects and how much it affect the structure in deflection calculations are shown in the report. In addition, the design method applied in the static report (LRFD: Load and Resistance Factor Design or ASD: Allowable Strength Design) and the relevant load combinations should be specified.

– In steel structure designs, details such as cold-formed profiles, welding details and connection safety factors, bolt diameters, welding type should also be specified in the report. Accordingly, drawings of the assembly and manufacturing details of the joints of steel structural elements should also be detailed.

– Details of the use of materials and methods to protect steel elements against corrosion should be specified in the report. It is important to protect the materials used at the joints against corrosion.

– Fire resistance of steel elements and their behavior during fire should be addressed in the report. The use of fire-resistant coatings and the performance of steel members against fire should be evaluated in the report.

– Diagrams showing the force and moment distributions in steel members help to understand the design and to size the members correctly. In addition, shear force and bending moment analyses acting on steel members are critical in determining the bearing capacity of the members.

– Analyses and measures taken to assess the earthquake resistance of steel structures should be clearly stated in the report. In the report, the measures taken and analyzes performed should be clearly stated. This allows an accurate assessment of the resilience of steel structures against earthquake effects.

In conclusion, steel static calculation reports are important tools for building reliable and durable structures in the construction industry. By referring to these reports in steel structure projects, engineers ensure the correct design of structures and manage a safe construction process.

The solution equations to CFD analysis consist of a set of coupled differential equations and can be theoretically solved for a given flow problem using methods derived from the analysis. These equations are known to be solved by complex mathematical methods known as Boltzmann Equations, Navier Stokes Equations, Euler Equations, Full Potential Equation, Prandtl-Glauert Equation, etc. Equations that are difficult to solve analytically have been solved using CFD analysis, enabling faster and more accurate information to be obtained as opposed to manual solutions.

Thus, CFD analysis has been used in many fields of study. Especially in ventilation systems, medical, vehicle aerodynamics, ship hydrodynamics, industrial equipment, pump systems, fuel cells and many other fields.

In addition, turbulent, multiphase and supersonic flows can be easily modeled for CFD analysis and the velocity, pressure, temperature, density of fluids can be easily analyzed. Nowadays, the widespread construction of high-rise buildings requires flow analysis.

The analysis of high-rise buildings under wind loads can be calculated by CFD analysis. Accordingly, they are very much affected according to the wind loads coming to the structure, as well as the formation of such winds in depth and allows for analysis. Thanks to CFD analysis, CFD analysis can also simulate curved flow and internal flow movements that cannot be achieved in wind tunnels.

By analyzing the design modeled through Computational Fluid Dynamics in combination with airflow models, temperature distribution and heat transfer studies, it enables the solution to generate scenarios that minimize energy consumption, reduce costs and improve accuracy.

CFD model design involves designing the geometry model, designing the grid model and setting the boundary conditions. Therefore, it is the most time-consuming process, which is a pre-processing for CFD analysis. Each process has an important role in determining the accuracy of CFD simulation results. Consequently, it is important to design the appropriate CFD model by choosing the right methods.

Furthermore, Computational fluid dynamics (CFD) can also be used to investigate the behavior of liquids and gases in complex systems designed in areas such as aerospace, shipping, automotive and energy industries. CFD simulations are also applied to analyze the effects of environmental factors such as weather conditions on the performance of a system. The main reason for using the CFD method is that it makes it possible to provide realistic operating conditions that include important issues related to modeling, design, and operation. The benefits of CFD analysis are listed as follows:

-With the CFD method, there is no need for high costs by obtaining results in computer environment without the need for physical experiments. Thanks to this, it saves time by providing results and analysis in a shorter time.

-In the simulation of the model designed in CFD analysis, gas leaks, the spread of chemical substances and malfunctions that may occur in the model designed in the simulation visualizes the dangerous situations with simulation and helps to predict the safety issues of the model and to make it in accordance with the standards.

-CFD analysis can be used to optimize modeled designs and improve yield performance.

-By providing a different perspective on fluid dynamics, it helps to visualize complex phenomena in three dimensions that are difficult to observe in physical experiments from every angle. As such, CFD simulations can be used to visually analyze the effects of environmental influences on the performance of a system. As a result, their behavior can be studied.

-CFD allows us to easily see all kinds of conditions without physical constraints of various scenarios, conditions and design changes. As a result, it helps to improve according to the detailed results in this regard.

-The CFD approach achieves this goal better than other theoretical or experimental methods. For example, advances in technologies in the field of air conditioning allow us to obtain increasingly clearer information on the flow within the living space.

In summary, the use of CFD simulations in selected areas offers a wide range of benefits, including cost and time savings, safety aspects, risk considerations and exploring many innovative design perspectives.

During the silo application phase there are technical problems caused by limitations of design standards, weak design and periodic loading and unloading. Possible solutions include post-tensioning and reinforcement of concrete with corrosion resistant materials such as fiber reinforced polymers.

In post-tensioning designs, it is important to apply a suitable volume of the silo, to ensure good protection of the material and to make filling and unloading easy; statically, it is important to check the stability, strength, displacement, and crack widths of the structure.

Silos can be easily deformed due to non-uniform lateral pressures. As a result, it is necessary to work with experienced civil engineers in silo retrofitting projects.

An engineer doing a silo retrofitting project must first calculate the seismic analysis and be able to check the damage that may occur in terms of prevention. In addition to the static pressures of the materials stored in the silo, it also creates different dynamic pressures due to the friction of the particles among themselves and on the silo wall during seismic movement.

As a result, when post-tensioning is applied to the outer perimeter of the silo, it plays a major role in extending the life of the structure by safely strengthening the structure by reducing the lateral pressure of the silo.

In addition, during destructive earthquakes, silos are also subjected to buckling and normal shear stresses generated by the material inside the silo. Therefore, the magnitude and distribution of the forces generated in the silo vary according to the lateral pressure effect of the material inside and the occupancy rate of the silo. Silos with larger or heavier materials create a significant pressure in the structure due to the lateral load effect.

Considering the characteristics of the material to be stored in the silo, the calculation of the loads on the base and walls of the silo must be made in accordance with the principles specified in various specifications and regulations.

Quality design and workmanship in silo construction is very important to serve your activities well. Partnering with a reputable and experienced engineer and contractor will help guide your decision-making process. In the silo retrofitting project, a comprehensive static evaluation should be taken and the project should be entered into implementation. In this way, Silo reinforcement with post-tensioning will contribute to durable performance for many years to come.

During the design of cantilever slabs, attention should also be paid to the vibration behavior of the slabs under loads. Vibration action can be critical for comfort of use on long cantilevers.

The TS3233 regulation, which is valid for prestressed elements in our country, is used in post tensioning design, but when necessary, the relevant parts of the more up-to-date ACI and Eurocode are also used.

To explain the post-tensioning application steps, respectively;

Design Phase: In the design phase, design alternatives are studied by using computer software in order to reach the most economical, applicable and not exceeding the limitations solution. As a result of the analyzes and optimizations made, a design is made that can safely resist the loads that may occur throughout the life of the building. Designing also includes determination of slab thickness, amount of mild reinforcement, number of tendons and tendon locations.

Tendon Placement: First, protective walls called galvanized duct or tube are placed on the chair reinforcements. Then the tendons are placed inside these ducts.

Anchoring and Fixing: Anchoring should be done in accordance with the project and this should be checked. Anchorage and fixation are important to prevent tendon slipping.

Concrete Pouring and Compaction Process: After the tendons are placed, concrete is poured. During the pouring of concrete, there should be no gaps in the sections where the tendons are located. The quality of concrete placement directly affects the tensioning process.

Tensioning Process: After the concrete reaches a certain strength, a tensioning process is applied as much as the force determined in the design. Tensioning is done with a special hydraulic machine.

Maintenance: After the concrete is poured, it is waited for a certain period of time to reach sufficient strength. During this period, curing should be done to prevent cracks and increase the strength of the concrete.

What are the advantages of post-tensioning in cantilever slabs?

• Since thinner slabs can be designed with post-tensioning design, it can create positive effects in terms of architecture.
• Deflection limits that cannot be achieved with conventional reinforced concrete design can be achieved by post tensioning method.
• Thanks to the reduction of the floor thickness and reduction of mild reinforcement quantity with post-tensioning, a more economical solution can be obtained compared to the design made with conventional reinforced concrete.

Silo bodies are one of the most important structural components of silo structures. The body part is designed depending on the lateral pressure created by the stored material. In addition, different loadings that will occur when the silo is full, empty and dumping should also be considered during the design phase.

Today, the post-tensioning method is used in the design and retrofitting of reinforced concrete silos. Thanks to the post-tensioning system, it is possible to design thinner silo bodies. As a result, the volume of concrete used will be significantly reduced and it will be possible to make a more economical solution.

It is desired that the stored products be in an environment protected against moisture, and for this, impermeability becomes an important feature. Due to the creep properties of concrete, cracks may occur in the body part of the filled silos. Cracks in the body can be prevented by applying the post-tensioning system in the silo body. The ability to design a thinner and uncracked body with the post-tensioning system makes the use of post-tensioning in silos widespread.