Mehmet Kamanli

Experimental and Analytical Study of Masonry Constructions Reinforced with Bed Joints

Abstract In this study, investigation was conducted on the out-of-plane fracture under repeated reversing loads of specimens of unreinforced masonry wall models, a suitable building material found worldwide, strengthened by bed joints using FRP (fiberglass reinforced plastic) with epoxy resin, by production of two separate wall samples composed of materials with identical characteristics in a 1 : 1 ratio. It was also observed that the fracture type became brittle and the pour lines indicated that it did not have tensile strength. Approximately, a 3.5 increase in withstanding breakage under seismic forces was observed in the performance of the wall strengthened by FRP with epoxy reinforcements in the bed joints. Furthermore, the shear strength of the model masonry wall was 48 % less than that attained in the wall strengthened by bed joints and it was determined that the energy absorption of the model masonry wall was 22 % less than that of the wall strengthened by bed joints. Additionally, while the masonry wall in the test which was not strengthened broke under repeated reversing loads at 65 kN, the break load of the strengthened masonry wall was ascertained to be 80 kN. The accuracy and application of the results of the studies conducted were also scrutinized by running finite element stress analysis and numerical solutions using an ANSYS computer-supported analysis program.

Sudden Complete Collapse of Zumrut Apartment Building and the Causes

AbstractIn recent years, buildings and structures in Turkey have frequently failed or suddenly sustained damage because of their own weight or other loads. The most dramatic failure was the Zumrut Apartment Building disaster: a 9-story RC building in Konya that collapsed on February 2, 2004, leaving 92 people dead. This study will investigate the cause of the building damage and failure. The significant mistakes made during the design and construction of the building will also be considered. This study was divided into three sections: site investigation, analytical study, and experimental study. The evaluation of the building failure relating to the vertical load-bearing members will be presented using observations from the site investigations, the test results obtained from specimens taken from the failed building, and the findings of an analytical study involving modeling the building using the finite-element method.

Modelling and Experimental Study of Mechanical Behaviour of Walls Produced by Different Knitting

Abstract This study aims to investigate the shear behavior and resistance of brick walls produced by various knitting types. For this purpose, 15 samples were produced using Holland knitting, block knitting, cross knitting, lock knitting, and plain knitting. The samples were forced in experiments to collapse and in the non-linear region, the changes in the samples related with shear forces and shear rigidity of the wall sections were determined. In the performed experimental study, the standard sliding resistance test technique for the masonry wall samples has been determined as recommended in ASTM Standard 1391-81. The numerical modeling was carried out by the finite elements method with the program package Ansys, taking into account the local mechanical parameters of bricks and mortar. The behavior of the experimental samples and the cracks occurred during the experiments were analyzed and shear stress graphs and load-displacement graphs were derived. The modeling with the Ansys program was compared with the experimental results and the most appropriate wall knitting type could be proposed.

Artificial neural network design for behaviours of reinforced concrete column under axial load and comparison of experimental study

Construction (building) sector is one of the sectors which adapt the rapid development of the technology. Especially in frame (skeleton) systems, very serious studies on columns that are vertical conveyors (carriers) are being done. Generally, these studies are implemented by experimentally and computer software is used in these studies as they offer good results. Artificial neural network (ANN) has been used in several engineering application areas including civil engineering. The use of ANN to predict the behaviour of reinforced concrete (R/C) members, using the vast amount of experimental data as a test-bed for learning and verification of results, proved to be available method for carrying out parametric studies. In the present study, columns under the axial load were manufactured from concrete that has been produced without carrying out the standards. Load conveying capacities and tension-unit deformation relationships of columns manufactured with different geometrical and equipment (outfit) properties and same cross-section area have been investigated. At the same time, research has been done via modelling by using ANN that is one of techniques of artificial intelligence and gained importance in recent years. SPSS statistical packet program is used to evaluate the results of this research. After comparisons of results obtained in the experiments, it has been determined that square column samples have the most axial load conveying capacity. It has also been determined that number of displacement is less in samples of columns wrapped (winded) with fret comparing to samples of columns wrapped with stirrup. The same results are obtained after modelling by ANN. As the result of statistical analyses that have been done in %5 reliability interval between data obtained from experiments and ANN, it has been seen that ANN can be used as reliable method.

An Experimental Study On Behaviour Of Variable I Sectioned Beams Under Flexure Produced By Normal And Lightweight Concrete

Nowadays, prefabricated in industrial structures, having long spans and in structures having high loads with long spans, selected cross-sections and construction materials become important to produce optimal members. Researches on normal, lightweight concrete beams, having variable I cross sections according to moment variation along the span and stress variation along the section height will give important results for optimal design of members. As a result 111 scaled, variable sectioned I beams made of lightweight and normal weight concrete are tested and relation between load and deflection, cracking mechanism and energy absorption capacities are obtained and compared for both materials. Also, research had given idea if the calculation method being used for reinforced normal concrete beam members under flexure is valid and can be used for lightweight concrete members.

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.

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.