Time history deformation based nonlinear analysis of tall reinforced concrete buildings using fiber model

Potentially, we are located in a seismic zone where significant earthquakes can occur. Therefore, it is important to guard against devastating effects that can result in loss of life. One of the best things to do for this purpose is to build earthquake-resistant structures. In particular, it is important to study this complexity since it uses quite different methods to determine the performance of structures against earthquakes. To ensure the safety of structures against earthquakes, it is necessary to install a carrier system, in which non-linear behavior is taken into account. (Zhang, R. 2019). This topic is a method made mandatory by TBDY2018 (Turkish Building Earthquake Regulation 2018) especially for tall buildings. Nonlinear modeling is important for understanding the realistic behavior of structures under earthquakes. This modeling requires detailed analysis of structures during earthquakes, taking into account the elongation and shortening that will occur in the material fibers. These analyses are based on non-linear solutions in terms of materials and geometry, taking into account second-order effects. This study develops a new method to evaluate the earthquake performance of tall buildings using OpenSees software. In particular, the aim of this study was to use an analysis approach within the scope of TBDY2018, in which the non-linear behaviors of the structures were taken into account. This allows the structures to react more realistically to the actual earthquake effects. In the analyses, a total of 22 earthquake acceleration records obtained from past earthquakes were used and these records were scaled according to the scaling conditions specified in the regulation. This enables a more accurate and realistic evaluation of the performance of the structures. In the study, the design and evaluation approaches required to ensure the building performance levels specified in TBDY2018 were examined. Thus, it helps to ensure the safety of buildings against earthquakes in order to prevent loss of life and property. This method can contribute to increasing the safety of buildings against earthquakes. The behavior and properties of steel and concrete structures are discussed in detail in the third section. Here, the focus is particularly on the inelastic behavior of the fiber model and solution methods. These methods are called displacement-based rigidity and force-based flexibility, and cracks and other damage situations are examined accordingly. Although the strength-based structural model has a simple calculation base, it needs to use the finite element approach. In the finite element approach, the Newton-Raphson technique is used to solve differential equation series. However, the application of this approach requires more complex analyses. It is also important to comply with local earthquake codes and standards, because the earthquake risk and structural requirements of each country may be different. For more explanation, detailed information is given, especially on how the inelastic behavior of the fiber model is observed and how the solution methods are considered in the data analysis stage. In addition, an explanation is given on how the element modification form of the strength-based model is simplified and why existing finite element programs generally use strength-based models. (Rao, S. S. 2019). Within the scope of TBDY 2018, shapeshifting performance is taken into account in the design of new buildings. Design Earthquake Class, Building Use Class, and Design Earthquake Classes are defined and associated with the calculation and valuation of buildings. Accordingly, some performance goals and valuation and design approaches are presented in the construction of reinforced concrete buildings in accordance with the 'Earthquake Design Class'. In new buildings, building design and valuation techniques are discussed, non-linear solution technique is explained in detail. The terms of nonlinear behavior models are introduced and the deformation limits corresponding to the performance levels are specified according to the properties of steel and concrete. Within the scope of TBDY 2018, deformation performance, design criteria, calculation methods and nonlinear behavior models were discussed in detail in the design of new buildings. In the building to be built, the number of basement floors and ground characteristics significantly affect earthquake loads. It is also known that with the use of active stiffness moment in the parts of the sections consisting of plastic joints in the design, there will be a decrease in performance as the moment decreases. However, in the regulation in TBDY 2018, it is stated that the curtain stress value is important. However, effective cracked section stiffness is used in the design and as the rigidity decreases, there is a decrease in earthquake forces. However, since the use of cracked section stiffness increases the translations, it becomes difficult to achieve the limit values. In this case, it may be necessary to use a larger column or to increase the ductility of the column by reducing the stirrup intervals. Due to the vertical loads, the size of the columns with a high normal force effect has been increased. In this context, the modified conditions set for scaling operations are mentioned and it is shown how these conditions are implemented by the developed program. Some performance targets and valuation techniques are used in the construction of reinforced concrete buildings in accordance with the 'Earthquake Design Class'. Nonlinear solution techniques are also explained in detail. The deformation limits corresponding to the performance levels are specified according to the properties of steel and concrete. Soil properties (hardness, damping) significantly affect the seismic performance of the structure, and these effects have been taken into account. In the design of new buildings, factors such as basic features, structural system characteristics, performance targets, material properties and soil-structure interaction are discussed in detail. (O'Reilly, G. J. 2018). With the scaled acceleration loaded into SAP2000 and STA4CAD program, the maximum displacement was found by nonlinear analysis in time domain and the spectral acceleration value was obtained by multiplying by 𝜔2. The spectral acceleration value obtained from the scaling program and the spectral acceleration value obtained from SAP2000 are shown and shown to be approximately the same. A 25-storey reinforced concrete building was designed by mode coupling method and its sections and reinforcements were determined. Nonlinear dynamic analysis of the building was performed with both programs (SAP2000 and STA4CAD) and the variation of end displacements with respect to time was compared. By using the sections and reinforcements obtained as a result of the design, analysis and evaluation were made according to the displacement within the scope of TBDY2018 with OpenSees program. In the analyses, 22 scaled earthquake acceleration records were used and for each earthquake record, the strain and shortening values in concrete and reinforcing steel were compared with the limit values in TBDY2018. The results are evaluated and the structural performance for both cases are compared and recommendations are made.