Comparision of 2007 and 2017 earthquake codes on a existing reinforced concrete building

Current progress in structural engineering is required to be included in earthquake codes for many reasons, such as new greater safety, affordability, and applicability. Earhquake codes are renewed at regular intervals so that the developments experienced in the field of structural engineering can be included in the codes. In our country earthquake codes are updated at regular intervals for this purpose. In the last fifty years, our earthquake codes were renewed in 1968, 1975, 1998 and 2007. In 2016, a code draft has been released for the renewal of the 2007 code. In this new regulation, non-linear calculation methods, which become increasingly used in structural engineering, became more important. Within the scope of this thesis, an existing reinforced concrete building which is evaluated by linear methods according to the 2007 code in Istanbul has been assessed separately by using non-linear methods according to the 2007 earthquake code and 2016 draft code. The static push over analysis method can not be used when the building is being evaluated because of the low attendance of the first mode of the building and because of the being torsional irregularity on the building. Instead of that, nonlinear time history analysis is used. The results of the analysis which are found separately by using 2007 and 2017 codes are compared. It is desired to see what kind of differences may occur regarding the evaluation of a reinforced concrete building with the renewed earthquake code. The thesis consists of four parts in total. First section is the introduction section that is given information about the content of the work. In the second part, changes in the updated code regarding evaluation of existing reinforced concrete buildings is described. With the new code, the number of information levels defined for existing reinforced concrete buildings has been reduced. The minimum requirements for a comprehensive knowledge level are also stretched. When determining the existing concrete material strength with the renewed code, the mean minus the standard deviation value, and 0.85 times the mean value are compared to the each other and the larger one is used. However, in calculations according to 2017 code, the average minus standard deviation value is taken as the strength of the existing concrete material, although the 0.85 times average value is larger in this thesis. The definition of the design spectrum has changed dramatically. A design spectrum with a larger spectral acceleration value is defined as the lateral design spectrum. For the first time definition of the vertical design spectrum was included in the earthquake code. The minimum number of earthquake records to be used has been increased to 11. However, within the scope of this thesis, seven earthquake records were used as the minimum number of earthquake records for the 2007 code. The conditions that are used when earthquake records scaling are changed. In addition, the draft code stipulates that the confining effect of 30% of transverse bars, can be taken into consideration when determining the damage limits. In draft code it is stated that the strain demands obtained for S220 bars are increased by 50 percent and the damage limits are reduced in the case of increasing shear force ratio. In the third part, the existing reinforced concrete building has been analyzed. The geometry of the building and the structural system of the building are introduced. A summary of the results of the linear elastic evaluation of the structure is given. As a result of linear evaluation, the 3rd floor is the most damaged floor in the structure. The 3rd floor members are selected for comprasion. One coloumn from "belirgin damage level", one coloumn from "ileri damage level", one coloumn from collapse level, one wall from "minimum damage level", one wall from collapse level are selected for comprasion. Since the existing building is not suitable to be solved by push over analysis, it is solved by nonlinear time history analysis according to 2007 earthquake code. According to the 2007 code cracked section stiffnesses are determined. Plastic behavior is defined in column beams and walls. Seven earthquake teams selected from the North Anatolian Fault Line earthquakes were scaled by changing the frequency content according to the design spectrum of the 2007 earthquake code. Under the scaled earthquakes, the plastic rotation demands of the system were obtained. Strain demands were obtained in the selected columns and wall members and compared with the damage limit values. The same procedures that have been carried out according to 2007 code, are carried out one more time for 2017 code. Damage levels of selected members are calculated by using nonlinear dynamic analyzes according to 2007 and 2017 codes. Calculated values are compared. The comparisons made can be summarized as follows: According to the 2017 code, the maximum shear force value obtained is 10166 kN, whereas in 2007 code this value is 7820 kN. When the mean values are compared, it is seen that with the analysis made according to the 2017 code, the shear force values are obtained about 10% greater than 2007 code. According to the results of the analysis made according to the 2007 code, the maximum value for building top displacement is 0.17 m in X direction and 0.19 m in Y direction. In the calculations made according to the 2017 code, the same values are seen as 0.18 m and 0.2 m respectively. When the average of the results obtained for 7 earthquake records is examined, it is seen that the analysis made according to the 2007 code has requested the top displacement of 0.13 m in the positive direction and 0.09 m in the negative direction. According to the 2017 code, mean top displacement demand is 0.135 m in the positive direction and 0.1 m in the negative direction. The mean maximum values of story drifts are 0.0167 m in the positive direction and 0.012 m in the negative direction as the result of the analysis made according to the 2007 code. As a result of the analysis made according to the 2017 code, the positive direction is 0.0174 m and the negative direction is 0.013 m. The S01 column, which is found in the collapse damage level as a result of linear evaluation, is found in the collapse damage level by using nonlinear time history analysis method for both the 2007 code and the 2017 code. The S07 column, which is found in the "ileri damage level" as a result of linear evaluation, is found in the collapse damage level by using nonlinear time history analysis method for the 2007 code and "minimum damage level" for the 2017 code. The S09 column, which is found in the "belirgin damage level" as a result of linear evaluation, is found in the "minimum damage level" by using nonlinear time history analysis method for both the 2007 code and the 2017 code. The P01 wall, which is found in the collapse damage level as a result of linear evaluation, is found in the "belirgin damage level" by using nonlinear time history analysis method for both the 2007 code and the 2017 code. The P02 wall, which is found in the "minimum damage level" as a result of linear evaluation, is found in the "belirgin damage level" by using nonlinear time history analysis method for both the 2007 code and the 2017 code. In the fourth section, the results are mentioned according to the comparison made. When the periods that calculated by the cracked sections of the building compared, it seems that the period of construction has increased with the new code. New seismic code provide smaller effective section stiffnesses. Thus it can be considered that the new draft regulation has remained on the safer side in terms of section account. Shear force values are increasing in the analysis results made according to the 2017 code. It is stem that the used earthquake records that are scaled by the increasing design spectrum. According to the 2017 code, it is seen that the deformation demand obtained in the sections are smaller than the analyzes made according to the 2007 code. Analyzes made according to the new draft code show that even though the building has larger shear forces and displacements, there is less damage to the elements.