Alptug Unal

Betonarme Kirişlerin Basit ve Ankastre Mesnet Koşullarında Kesme Davranışının Araştırılması

Yapi tasiyici sisteminin onemli bir parcasi olan betonarme kirisler ile ilgili bir calisma yurutulmustur. Bu calismalarda genellikle basit mesnet sartlari dikkate alinmistir. Ancak, betonarme binalarin mesnet bolgelerinin ankastre mesnet sartlarina daha yakin oldugu bilinmektedir. Bu calismada, betonarme kirislerde mesnet sartlarinin degisimin kiris kesme dayanimina etkisi arastirilmistir. Bu amacla, 4 adet tam olcekli betonarme kiris deney elemani 4 noktali egilme sisteminde test edilmistir. Bu deney elemanlarindan iki tanesi basit mesnetli, iki tanesi ise ankastre mesnetli olarak test edilmistir. Deney elemanlarinin davranislarinin belirlenmesi icin yuk-deplasman egrileri cizilmis, rijitlik ve enerji tuketim kapasiteleri belirlenmis ve deney sirasinda catlak olusumlari gozlemlenmistir. Deney sonuclari incelendiginde, ankastre mesnetli deney elemanlarinin davranislarinin, ayni ozellikteki basit mesnetli deney elemanlarinin davranislarindan oldukca farkli oldugu gorulmustur.

Investigation of Plastic Hinge Length in Reinforced Concrete Columns on Column Behavior

In reinforced concrete buildings in case of a possible earthquake, the buildings slamp as they lost their horizontal stability because of hinging of column ends. The assumptions for plastic hinge lengths are present during project stage of reinforced concrete buildings. According to Turkish Earthquake Regulations, although plastic hinge length is determined to be 0.5h, its known that plastic hinge length is determined via various formulas in some other regulations all over the world. In reinforced concrete columns, its necessary to indicate the effect of plastic hinge length on the column behavior. For this purpose, pushover analysis of 5 column samples having different plastic hinge lengths was performed with non-linear analysis program. As a result of pushover analysis, situations of plastic hinges formed in columns and their load-displacement curves were determined. The graphs and the data were compared and the results were discussed.

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.