When the existing literature is examined, it can be seen that many studies have been carried out to improve the mechanical properties of concrete by using waste or additive materials with different mechanical and physical properties in various proportions instead of the conventional aggregate used in concrete production. Within the scope of this study, it was aimed to examine the physical and mechanical properties of the samples fabricated using natural perlite aggregate instead of conventional aggregate by exposing them to high temperature effects. In this context, a total of 96 concrete samples will be fabricated, including 48 rectangular prism beams with dimensions of 10x10x40 cm and 48 cube samples with dimensions of 15x15x15 cm, with a concrete compressive strength of 25 and 40 MPa, using perlite and conventional concrete. The samples were planned to be exposed to temperature effects of 200ºC, 400ºC and 600ºC at room temperature. Afterwards, the samples will be examined with destructive/non-destructive methods such as mass loss (ML), ultra sound transmission rate (USTR), compressive strength (CS), elasticity modulus (EM)and pure bending (PB) test, and the mechanical and physical properties of all samples will be compared.
In this study, the earthquake behaviour of the historical Çadırcı Bathhouse in Erzincan, which is located on the North Anatolian Fault, the most active fault line of Turkey, was investigated. This historical masonry structure has preserved its structural integrity despite being exposed to two earthquakes of magnitude 7.8 in 1939 and 6.7 in 1992. In accordance with the architectural survey studies, the historical building was modelled in 3D in two different types according to shell and solid modelling techniques. According to the results of response spectrum analysis, stress and displacement distributions and modal characteristic parameters of the structure were evaluated. When the analysis results of the models created with the solid model technique and the shell model technique are compared, it is concluded that the shell modelling technique is safe in such studies, considering the analysis time and modelling difficulty. According to the results of the analyses, considering the stress distribution in the historical building elements, it is seen that the configuration characteristics of historical masonry structures are important in earthquake resistance like other building systems.
Günümüzde betonarme yapılar oldukça yaygın kullanıma sahiptir. Bu yaygın kullanım bu alana olan ihtiyacı gün geçtikçe artırmaktadır. Betonarmenin günümüzde farklı alanlarda kullanılma ihtiyacının artması, beton teknolojisi alanında da bazı gelişmelere neden olmuştur. Betona olan bu ihtiyaç zamanla başka alternatiflerin ortaya çıkmasını kaçınılmaz hale getirmektedir. Betona olan bu ihtiyaç, hammaddesi olan agrega için bizleri alternatif düşünmeye teşvik etmiştir. Ülkemizin rezervleri açısından zengin olarak bulunan perlit, geleneksel betonda kullanılan agregaya göre daha hafif, sürdürülebilir, ekonomik bir malzeme olması sebebiyle araştırmaya konu olmuştur. Perlit rezervlerimizin çok bulunmasına karşın bu rezervlerin sadece belirli bir kısmını kullanmamız ve perlitin sadece inşaat sektörü için yalıtım malzemesi olarak kullanılması büyük bir eksiklik olarak görülmektedir. Bu bağlamdan yola çıkarak doğal ham perlit agregasını kullanarak yapısal eleman üretilmiştir. Çalışma kapsamında C20 ve C40 basınç dayanımlarına sahip geleneksel ve perlitli olmak üzere her basınç dayanımından 2’şer adet betonarme kolonu üretilmiştir. Üretilen betonarme kolonlar sabit eksenel yük ve tersinir tekrarlanır yanal yükleme altında deneyleri gerçekleştirilmiştir. Farklı beton basınç dayanımlarında hem perlitli hem de geleneksel betonarme kolonlarının yapısal davranışı incelenmiştir. Yük-deplasman, süneklik, rijitlik ve enerji yutma kapasiteleri bakımından bu iki malzeme için davranış farklılıkları ortaya konularak, perlitin agrega olarak kullanılabilirliği araştırılmıştır. Deneysel bulgular neticesinde perlitin betonarme kolonlarda agrega olarak kullanılmasıyla taşıma gücü kapasitesi bakımından olumlu sonuçlar elde edilmesine rağmen, perlitli kolonların süneklik, rijitlik ve enerji yutma kapasiteleri bakımından geleneksel betonarme kolonlara göre yetersiz olduğu sonucuna varılmıştır.
Tasarım aşamasında betonarme döşemeleri kolon, kiriş gibi yük ve/veya moment taşıyan elemanlardan ayıran temel özellik kesme kuvvetinin beton tarafından karşılanarak enine donatıya ihtiyaç duyulmamasıdır. Buna ek olarak betonarme kiriş ve döşemelerinde eğilme davranışları kısmen birbirine benzerlik gösterse de korozyon oluşumu durumunda davranış farklıdır. Araştırma kapsamında monotonik eksenel eğilme yükü etkisi altında olacak şekilde laboratuvar şartlarında üretilecek bir (1) adedi referans numune olmak üzere toplam altı (6) adet iki doğrultulu ve korozyonlu betonarme taşıyıcı döşeme plaka numunelerinin deneysel çalışmalarının yürütülmesi planlanmıştır. Üretilecek betonarme taşıyıcı döşeme plaka numunelerin korozyona uğratılması amacıyla hızlandırılmış bir korozyon yöntemi kullanılacaktır. Araştırma kapsamında tasarlanan farklı düzeylerdeki korozyon sevilerinin gerçek değerleri, monotonik eğilme testlerinden sonra betonarme numuneler kırılarak ve tüm donatı çubukları çıkarılarak, yapılacak olan gravimetrik çalışmalar ile belirlenecektir. Betonarme taşıyıcı döşeme plaka numunelerinin her iki kısa ve uzun doğrultularındaki korozyon seviyeleri, Kırılma (Akma) Çizgileri Teorisine dayanan iki her iki doğrultuda belirlenecek olan moment kapasiteleri açısından dikkate alınacaktır. Böylece, her iki doğrultuda elde edilen gerçek korozyon seviyeleri ile moment taşıma kapasiteleri, test sonuçlarının 12 (on iki) adet korozyonlu betonarme döşeme plakaları için tartışılabilmesi sağlanacaktır. Moment taşıma kapasitesi için araştırma kapsamında geliştirilecek olan bir yeni model ile literatürde bulunan daha önceki çalışmalara ait verilerin doğrulanması yapılabilecektir.
One of the most important earthquake indicators that buildings should have is ductile behavior. Due to the limited tensile strength of concrete, alternative materials such as structural Nano-synthetic fibers as three-dimensional reinforcement bars have already gained increasing popularity for several decades. However, the contribution of nano-synthetic fibers to the adherence length of reinforcement bars has not been investigated so far. Therefore, in this study, an experimental study was conducted to investigate the effects of nano-synthetic fibers on the development length of reinforcement bars. The number of experimental reinforced concrete slab specimens to be fabricated in terms of axial flexural tests was designed 33, depending on different development lengths and three different volume fractions of nano synthetic fibers as 0.0, 1.0 and 1.5%. Within the scope of the research, load displacement curves, energy absorption capacities, ductility ratios and bond-reinforcement slip relationships were obtained for different embedding lengths of reinforcement bars in 33 concrete slabs with three different amounts of nano-synthetic fibers used. As a result of the research, it has been revealed that the dominant effects of nano-synthetic fibers on structural behavior are their energy absorption capacity in plastic deformation. As a result of the research, it has also been discovered that with the help of the added nano-synthetic fibers, the ductile behavior is also regained for or reinforcement bars with reduced embedded length of more deformation capacity that can be accommodated by the reinforcement bars.
Turkey is a country that is vulnerable to earthquakes and has experienced many major earthquakes that completely destroyed or caused significant damage to numerous historic structures. Today, using computer software, it is important to numerically model and analyze historic structures that need significant restoration and strengthening, to evaluate them from a perspective of seismic resistance, and to reinforce them without altering their originality. In this study, a finite element model of the historic Tigris Bridge on the Tigris River was created. First, the stresses and deformation caused by its own weight were determined. Subsequently, dynamic analyses were performed in the time domain using past earthquake ground motion records. Displacement and stress values obtained for each earthquake record in these time domain analysis were compared to each other to evaluate the seismic behavior of the bridge comparatively. The seismic performance of the bridge was determined on the basis of the “Guidelines on the Management of Earthquake Risks for Historic Structures” published by the Directorate General of Religious Foun-dations in Turkey.
Earthquakes of magnitude Mw = 7.7 and Mw = 7.6 hit the city of Kahramanmaraş (Turkey) on 6 February 2023. These earthquakes caused serious damage in 11 provinces in Turkey resulting in over 50,000 deaths and huge economic losses with the collapse of thousands of buildings. Two consecutive devastating earthquakes have severely damaged the reinforced concrete building stock located in Malatya. There are many reasons reinforced concrete structures suffer damage under the influence of seismic loads. These reasons can be listed as material and section properties that do not comply with earthquake codes, workmanship defects, ground parameters that are not considered and design errors, as seen in field investigations after earthquakes in Turkey in the past. In this research, a field study was conducted on reinforced concrete buildings damaged after the earthquakes in Malatya province. The causes of structural damages in reinforced concrete buildings between 6–26 years of age were assessed in terms of design and material defects. The structural damages were mainly caused due to insufficient stirrups in structural members, short column, strong beam–weak column, failures of infill walls, soft story type collapse, poor concrete quality, and reinforcement corrosion. In addition to the field investigation, the spectrum relationships created using raw acceleration data obtained from DEMP (Disaster and Emergency Management Presidency) stations in Malatya province were compared with the design response spectra.
