Hasan Husnu Korkmaz

Rehabilitation of Infilled Reinforced Concrete Frames with Thin Steel Plate Shear Walls

AbstractDifferent rehabilitation methods have been suggested for system improvement of existing deficient reinforced concrete building stock in seismic hazard areas. Although the use of steel plate shear walls for the rehabilitation of steel frames is common, their application to deficient reinforced concrete frames is not as common. In this study, the efficiency of steel plate shear walls on deficient reinforced concrete frames having hollow clay tile infill walls is investigated. Five one-bay, two-story 1/3 scaled RC frames were subjected to quasistatic lateral loading. The results indicated that significant improvement may be achieved in the lateral frame response. Lateral load-carrying capacities and energy dissipation capacities were considerably increased. However, a local shear strengthening of deficient columns may be required since shear demand on the columns increases considerably owing to tension field forces of the steel plate shear walls.

Frequency of anemia in chronic psychiatry patients

Purpose Anemia could cause psychiatric symptoms such as cognitive function disorders and depression or could deteriorate an existing psychiatric condition when it is untreated. The objective of this study is to scrutinize the frequency of anemia in chronic psychiatric patients and the clinical and sociodemographic factors that could affect this frequency. Methods All inpatients in our clinic who satisfied the study criteria and received treatment between April 2014 and April 2015 were included in this cross-sectional study. Sociodemographic data for 378 patients included in the study and hemoglobin (Hb) and hematocrit values observed during their admission to the hospital were recorded in the forms. Male patients with an Hb level of <13 g/dL and nonpregnant female patients with an Hb level of <12 g/dL were considered as anemic. Findings Axis 1 diagnoses demonstrated that 172 patients had depressive disorder, 51 patients had bipolar disorder, 54 patients had psychotic disorder, 33 patients had conversion disorder, 19 patients had obsessive-compulsive disorder, 25 patients had generalized anxiety disorder, and 24 patients had other psychiatric conditions. It was also determined that 25.4% of the patients suffered from anemia. Thirty-five percent of females and 10% of males were considered as anemic. The frequency of anemia was the highest among psychotic disorder patients (35%), followed by generalized anxiety disorder patients (32%), and obsessive-compulsive disorder patients (26%). Anemia was diagnosed in 22% of depressive disorder patients, 25% of bipolar disorder patients, and 24% of conversion disorder patients. Results The prevalence of anemia among chronic psychiatry patients is more frequent than the general population. Thus, the study concluded that it would be beneficial to consider the physical symptoms and to conduct the required examinations to determine anemia among this patient group.

P wave dispersion in patients with hypochondriasis

P wave dispersion (Pd), defined as the difference between the maximum and the minimum P wave duration, has been associated with anxiety. Thus, we wondered whether Pd in hypochondriasis which is associated with anxiety differed from that in healthy controls. Pd was measured in 30 hypochondriac patients and same number of physically and mentally healthy age- and gender-matched controls. Hamilton Depression Rating (HDRS) and Hamilton Anxiety Rating Scales (HARS) were scored. The heart rate and left atrium (LA) sizes were not significantly different between groups. However, both Pmax and Pmin values of the patients were significantly higher than those of healthy controls. As for the main variable investigated in the present study, the corrected Pd was significantly longer in the patient group compared to control group. On the basis of this study, we can conclude that Pd may be related to hypochondriasis though our sample is too small to allow us to obtain a clear conclusion. Future studies with larger sample evaluating the effects of treatment are required.

The Structural Damages and Collapse Types in Turkey, Observed after the Recent Earthquake

In the last decade, the earthquakes in Turkey caused thousands of loss of life. The most unfortunate case was happened in 1999 Marmara earthquake and more than 20000 people lost their life. Recently an earthquake of magnitude 7.2 occurred in Van city and 600 dead toll was reported. Following the earthquake, the author was visited the earthquake region. In this study field reconnaissance survey the causes of failures observed on reinforced concrete (RC) structures were summarized. The main problem was the construction quality especially the concrete production process. The steel detailing was also a big problem for the region. The failed or damaged buildings were included several non-seismic details. The observed problems of damaged or collapsed buildings were short column formations, soft or weak stories, inadequate lateral confinements reinforcement, use of plain undeformed bars, poor material and concrete quality, lap spilice problems, strong beam-weak columns and weak beam-column joints.

Evaluation of a Gravity Load Designed Reinforced Concrete Structure Failed under its Own Weight due to Creep in Concrete

Turkish building stock is commonly composed of reinforced concrete moment resisting frames. Recent earthquakes in Turkey resulted thousands of failed or heavily damaged residential houses and office buildings. In addition of the earthquake failures, reinforced concrete structures may also failed only under their own weight. There are several examples such as Hicret Apartment in Diyarbakir (1983), Zumrut Apartment in Konya, in central Anatolia, Huzur Apartment in Istanbul (2007). On February 2nd, 2004 a 9-story reinforced concrete building in Konya (Zumrut Apartment) collapsed leaving 92 people dead. The first author of the paper was governmentally charged about the investigation of the failure causes. Carrot samples were taken from the concrete columns and steel samples were obtained from the disaster area. The dimensions of the structural members were determined. The structure was modeled in three dimensional space and vertical collapse analyses were conducted. The one of the main cause of failure was determined as the creep of the concrete occurred in excessively loaded columns. The main reasons of the damages and failures were determined to be the insufficiency in material quality, mistakes made in load selection and the inappropriate load-carrying dimensions. The construction mistakes and not obeying the design drawings are the other flaws. In this paper detailed information about the structure, creep analyses and vertical collapse analyze results were depicted in understandable format.

Strengthening of Reinforced Concrete Frames Not Designed According to TDY2007 with External Shear Walls

Recently repair and strengthening of existing buildings become a popular research topic. The strengthening of buildings necessitates the evacuation of the structure. On the other hand, school, hospital type structures must continue their function. In this study exterior shear wall addition to the existing exterior frames is proposed. Since the application is applied to the exterior of the building, the structure can continue its function during the application. In this study, 1/3 scaled 4 specimens were tested under reversed cyclic loading simulating the seismic action. First reference specimen was the bare frame and didnt contain a strengthening and tested to see the reference behavior. Specimens have several design mistakes to represent the existing older structures. The other specimens retrofitted with different configurations. The second specimen was strengthened with exterior shear walls and contained a window opening. The last specimen was also retrofitted with exterior shear wall but the shear walls were divided into two pieces. The load-displacement curves, envelope curves, relative displacement curves, energy absorption curves and rigidity curves were presented and compared within the paper. In the conclusion, the capacity increase of the frame was discussed and several recommendations were presented.

An Experimental Study on Reinforced Concrete Infilled Frames with Openings

In the last decade, seven major earthquakes caused significant casualties and extensive structural failures. Thousands of RC buildings were severely damaged or collapsed in Turkey due to various deficiencies. This has initiated experimental studies on strengthening methods and intensive researches regarding the rehabilitation of reinforced concrete structures by introducing reinforced concrete infill walls were carried out. Strengthening of reinforced concrete frames by cast-in-place reinforced concrete infills is commonly used in practice. Many structures were also repaired using this technique after the recent earthquakes. In this experimental research, six, one-bay/two-story, 1/3-scaled non-ductile, undamaged reinforced concrete (RC) frames were constructed and tested to investigate the behavior of frames strengthened by introducing infills with or without openings. The test specimens were subjected to reversed cyclic quasi-static lateral loading. The specimens were constructed with the most commonly observed deficiencies in residential RC buildings in Turkey. The first specimen was the reference bare specimen and contained no strengthening. The other specimens were infilled with RC panels with openings having different ratios and configurations. Strength, stiffness and storey drifts of the test specimens were measured and compared. Test results indicated that infilled RC frames displayed significantly higher lateral strength and stiffness than the non-ductile bare frame considerably.