Nonlinear finite element analysis of RC beams strengthened with CFRP strip against shear

Nalan Bulut,Özgür Anil,Çagatay M. Belgin 사단법인 한국계산역학회 2011 Computers and Concrete, An International Journal Vol.8 No.6

Strengthening of reinforced concrete (RC) members against shear that is one of the failure modes especially avoided by using carbon fiber reinforced polymer (CFRP) is widely used technique, which is studied at many experimental studies. However, conducting experimental studies are required more financial resources and laboratory facilities. In addition, along with financial resources, more time is needed in order to carry out comprehensive experimental studies. For these reasons, a verified finite element model that is tested with previous experimental studies can be used for reaching generalized results and investigating parameters that are not studied. For this purpose, previous experimental study results are used and “T” cross-sectioned RC beams strengthened with CFRP strips with insufficient shear strength are modeled by using ANSYS software. First, finite elements modeling of the previously tested RC beams are done, and then the computed results are compared with the experimental ones whether they are matched or not. As a result, the finite element model is verified. Later, analyses of the cases without any test results are done by using the verified model. Optimum CFRP strip spacing is determined with this verified finite element model, and compared with the experimental findings.

Determination by molecular methods of genetic and epigenetic changes caused by heavy metals released from thermal power plants

Bulut, Huseyin,Dogan, Nalan Yildirim The Korean Society for Applied Biological Chemistr 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.2

The heavy metals are released into the environment due to the activities such as meeting the increasing demand for energy, industrial activities, and agricultural pesticides. In many studies, the heavy metals have been proven to have genotoxic effects. As a result of burning the lignite coal in thermal power plants, the heavy metals of Cr, Fe, Mn, Cu, Pb, Cd, Zn, and Ni are spread into the environment within the ashes. In the present study, the gene expression levels were examined on the corn and wheat plants added with 500-m interval around the thermic power plant. For this purpose, the genes from 14-3-3 protein family, expression level of which increases under abiotic stress conditions, were analyzed. For the expression levels of plants, the $2^{-{\Delta}{\Delta}C_t}$ values were calculated and then compared to $2^{-{\Delta}{\Delta}C_t}$ values of ${\beta}$-actin gene, that is, the housekeeping gene. The heavy metal content analyses of the samples were carried out using ICP-MS, and it was determined that there were many heavy metals at higher amounts within the structure of samples having low level of gene expression. It has been understood that heavy metal stress causes a difference in gene expression level. The change introduced by heavy metal stress into the gene expression occurs in concrete in the translation products. The level of stress-induced gene expression, which is caused by heavy metals in the environment surrounding the plant, has been successfully determined by RT-PCR.

Determination by molecular methods of genetic and epigenetic changes caused by heavy metals released from thermal power plants

Huseyin Bulut,Nalan Yıldırım Dogan 한국응용생명화학회 2018 Applied Biological Chemistry (Appl Biol Chem) Vol.61 No.2

The heavy metals are released into the environment due to the activities such as meeting the increasing demand for energy, industrial activities, and agricultural pesticides. In many studies, the heavy metals have been proven to have genotoxic effects. As a result of burning the lignite coal in thermal power plants, the heavy metals of Cr, Fe, Mn, Cu, Pb, Cd, Zn, and Ni are spread into the environment within the ashes. In the present study, the gene expression levels were examined on the corn and wheat plants added with 500-m interval around the thermic power plant. For this purpose, the genes from 14-3-3 protein family, expression level of which increases under abiotic stress conditions, were analyzed. For the expression levels of plants, the 2DDCt values were calculated and then compared to 2DDCt values of b-actin gene, that is, the housekeeping gene. The heavy metal content analyses of the samples were carried out using ICP-MS, and it was determined that there were many heavy metals at higher amounts within the structure of samples having low level of gene expression. It has been understood that heavy metal stress causes a difference in gene expression level. The change introduced by heavy metal stress into the gene expression occurs in concrete in the translation products. The level of stress-induced gene expression, which is caused by heavy metals in the environment surrounding the plant, has been successfully determined by RT-PCR.

Strain distribution between CFRP strip and concrete at strengthened RC beam against shear

Anil, Ozgur,Bulut, Nalan,Ayhan, Murat Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.4

In recent years, CFRP material usage in strengthening applications gradually became widespread. Especially, the studies on the strengthening of shear deficient reinforced concrete beams with CFRP strips are chosen as a subject to numerous experimental studies and research on this subject are increased rapidly. The most important variable, that is affected on the failure mode of CFRP strips and that is needed for determining the shear capacity of the strengthened reinforced concrete beams, is the strain distribution between CFRP strips and concrete. Numerous experimental studies are encountered in the literature about the determination of strain distribution between CFRP strips and concrete. However, these studies mainly focused on the CFRP strips under axial tension. There are very limited numbers of experimental and analytic studies examining the strain distribution between concrete and CFRP strips, which are under combined stresses due to the effects of shear force and bending moment. For this reason, existing experimental study in the literature is used as model for ANSYS finite element software. Nonlinear finite element analysis of RC beams strengthened against shear with CFRP strips under reverse cyclic loading is performed. The strain distributions between CFRP strips and concrete that is obtained from finite element analysis are compared with the results of experimental measurements. It is seen that the experimental results are consisted with the results derived from the finite element analysis and important findings on the strain distribution profile are reached by obtaining strain values of many points using finite element method.

Strain distribution between CFRP strip and concrete at strengthened RC beam against shear

Özgür Anil,Nalan Bulut,Murat Ayhan 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.4

In recent years, CFRP material usage in strengthening applications gradually became widespread. Especially, the studies on the strengthening of shear deficient reinforced concrete beams with CFRP strips are chosen as a subject to numerous experimental studies and research on this subject are increased rapidly. The most important variable, that is affected on the failure mode of CFRP strips and that is needed for determining the shear capacity of the strengthened reinforced concrete beams, is the strain distribution between CFRP strips and concrete. Numerous experimental studies are encountered in the literature about the determination of strain distribution between CFRP strips and concrete. However, these studies mainly focused on the CFRP strips under axial tension. There are very limited numbers of experimental and analytic studies examining the strain distribution between concrete and CFRP strips, which are under combined stresses due to the effects of shear force and bending moment. For this reason, existing experimental study in the literature is used as model for ANSYS finite element software. Nonlinear finite element analysis of RC beams strengthened against shear with CFRP strips under reverse cyclic loading is performed. The strain distributions between CFRP strips and concrete that is obtained from finite element analysis are compared with the results of experimental measurements. It is seen that the experimental results are consisted with the results derived from the finite element analysis and important findings on the strain distribution profile are reached by obtaining strain values of many points using finite element method.