The slenderness effect on wind response of industrial reinforced concrete chimneys

Karaca, Zeki,Turkeli, Erdem Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.3

There are several parameters affecting the response of industrial reinforced concrete (RC) chimneys, i.e., the severity of wind and earthquake loads acting to the structure, structural properties such as height and cross section of the chimney, the slenderness property of the structure etc. One of the most important parameter that should be considered while understanding the wind response of industrial RC chimneys is slenderness property. Although there is no certain definition for slenderness effect on these structures, some standards like ASCE-7 define slenderness from different aspects of the structural properties. In the first part of this study, general information about the definition of slenderness in the well-known standards and ten selected industrial RC chimneys are given. In the second part of the study, brief information about wind load standards that are used for calculating wind loads namely ACI 307/98, CICIND 2001, DIN 1056, TS 498 and Eurocode 1 is given. In the third part of the study, calculated wind loads for selected chimneys are represented. In the fourth part of this study, the internal forces obtained from load combinations that are applied to chimneys and some graphs presenting the effect of slenderness on chimneys are given. In the last part of the study, a conclusion and discussion part is taking place.

The slenderness effect on wind response of industrial reinforced concrete chimneys

Zeki Karaca,Erdem Türkeli 한국풍공학회 2014 한국풍공학회지 Vol.18 No.3

There are several parameters affecting the response of industrial reinforced concrete (RC)chimneys, i.e., the severity of wind and earthquake loads acting to the structure, structural properties such asheight and cross section of the chimney, the slenderness property of the structure etc. One of the mostimportant parameter that should be considered while understanding the wind response of industrial RCchimneys is slenderness property. Although there is no certain definition for slenderness effect on thesestructures, some standards like ASCE-7 define slenderness from different aspects of the structural properties. In the first part of this study, general information about the definition of slenderness in the well-knownstandards and ten selected industrial RC chimneys are given. In the second part of the study, briefinformation about wind load standards that are used for calculating wind loads namely ACI 307/98, CICIND2001, DIN 1056, TS 498 and Eurocode 1 is given. In the third part of the study, calculated wind loads forselected chimneys are represented. In the fourth part of this study, the internal forces obtained from loadcombinations that are applied to chimneys and some graphs presenting the effect of slenderness on chimneysare given. In the last part of the study, a conclusion and discussion part is taking place.

Seismic assessment of historical masonry structures: The case of Amasya Taşhan

Zeki Karaca,Erdem Türkeli,Şenol Pergel 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.20 No.4

Turkey owns a very important cultural and historical heritage that bears the traces of thousands of years of culture and civilization. It is an inevitable duty to carry these treasuries to the future generations. In this paper, structural safety assessment and strengthening stages of one of these important historical heritages namely Amasya Taşhan was investigated in details as a case study. For this purpose, the detailed architectural projects of the structure with the information of all load carrying and structural elements were prepared. Then, the structural dynamic analyses were performed by using SAP2000. The internal forces obtained from the dynamic analyses determined the weak regions. By obtaining the information from dynamic analyses, the method of state of the art technique of application of the structure that needs structural strengthening was selected. The last step is the application of these precautions to the whole structure. At the end of this study, this study not also contains several strengthening techniques that is used in one masonry structure together but also provides a useful reference to the practicing engineers.

Response surface-based model updating to detect damage on reduced-scale masonry arch bridge

Emre Alpaslan,Zeki Karaca 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.1

Response surface (RS) methods, a combination of mathematical and statistical techniques, have been widely used in design optimization, response prediction, and model validation in structural engineering systems. However, its usage in structural damage identification, especially for historic structures has not been quite common. For this purpose, this study attempts to investigate damage detection in a masonry arch bridge. Within the scope of this, a reduced-scale model of a one span historical masonry arch bridge was built in a laboratory environment. To determine the modal parameters of the reduced-scaled bridge model, operational modal analysis (OMA) was performed under ambient vibrations. Signals originated by sensitive accelerometers were collected to quantify the vibratory response of the reduced-scaled model bridge. The experimental natural frequencies, mode shapes, and damping ratios resulting from these measurements were figured out by using the Enhanced Frequency Domain Decomposition (EFDD) technique. The three-dimensional model of the reduced-scale bridge was created in the ANSYS finite element (FE) software program to expose the analytical dynamic characteristics of the bridge model. The results obtained in the experimental application were compared with those of the finite-element analysis of the bridge model. The calibration of the numeric model was utilized depending on the experimental modal analysis results of the reduced-scale bridge by using the RS method. Design of experiments was constructed by using central composite design, and the RS models were generated by performing the genetic aggregation approach. The optimum results between the experimental and numerical analyses were found by using the RS optimization. Then, regional damages created on the scaled model and the changes of dynamic properties of the damaged case were evaluated. The damage location was approximately identified by using the RS method in the calibrated finite-element model. The results demonstrated that the RS-based FE updating approach is an effective way for damage detection and localization in masonry type structures.

Secondline Chemotherapy Versus Best Supportive Care in Patient with Malignant Pleural Mesothelioma: A Retrospective Study

Mutlu, Hasan,Buyukcelik, Abdullah,Karaca, Halit,Aksahin, Arzu,Berk, Veli,Aslan, Tuncay,Erden, Abdulsamet,Akca, Zeki,Ozkan, Metin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.6

Introduction: Mesothelioma is a rare neoplasm arising from mesothelial surfaces with the malignant pleural mesothelioma (MPM) as the most common form. Secondline chemotherapy in MPM is still controversial and in this study we evaluated whether it is superior to best supportive care. Materials and Methods: A total of 51 patients with MPM from Acibadem Kayseri Hospital, Kayseri Training and Research Hospital and Erciyes University were analyzed retrospectively. The patients treated with secondline chemotherapies (SLCT) were compared with those treated with best supportive care (BSC) for overall survival. Results: The median overall survival (OS) for firstline chemotherapy${\rightarrow}$SLCT and firstline chemotherapy${\rightarrow}$BSC groups were 20.3 and 14.7 months respectively (p=0.079). After firstline chemotherapy the median OS for SLCT and BSC were 5.9 and 4.7 months (p=0.355). Discussion: Although there was a trend for improvement in overall survival in patients treated with secondline chemotherapy, the difference was not statistically significant. Our results do not support the proposal that secondline chemotherapy could be effective in patients with MPM.

Computational investigation of the comparative analysis of cylindrical barns subjected to earthquake

Yousef Zandi,Mahdi shariati,Aminaton Marto,Xing Wei,Zeki Karaca,Duy Kien Dao,Ali Toghroli,Mir Heydar Hashemi,Yadollah Sedghi,Karzan Wakil,Majid Khorami 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.4

The structural behaviors of cylindrical barns as a specific engineering structure have been considered as a complicated computing process. The structure design against the earthquake load, to protect by using the code, is an urgency avoiding unexpected damages. The situation has been subjected to the applied design method if there would be no failure across the construction procedures. The purpose of the current study is to clarify the behaviors of cylindrical reinforced concrete barns through the analytic methods across the mass and Lagrangian approaches through the whole outcomes comparison indicating that the isoparametric element obtained from the Lagrangian approach has been successfully applied in the barns earthquake analysis when the slosh effects have been discarded. The form of stress distributions is equal with <i>s_z</i> closed distributions to one another.