Bu çalışmada 8 katlı tünel kalıp taşıyıcı sisteme sahip bina sonlu elemanlar metodu ile analiz edilmiştir. Yapı-temel sistemi için üç farklı zemin profili (ZC, ZD, ZE), üç farklı yükleme koşulu (1.4G+1.6Q; G+Q+EX, G+Q+EY) ve iki farklı temel modellemesi (ankastre çözüm, Winkler metodu) dikkate alınmıştır. Analiz sonucuna deprem kuvvetleri, tasarım ivme değerleri, periyodlar, zemin gerilmeleri, temeldeki oturmalar, kat deplasmanları ve perde tasarım kuvvetlerindeki değişim karşılaştırılmıştır. ZC’den ZE zemin sınıfına doğru gidildikçe TA ve TB arasındaki fark büyüdüğü için, ZE sınıfı zemin üzerine yapılacak yapıların maksimum ivmeye maruz kalma ihtimali diğer zemin sınıflarına göre daha fazladır. Ayrıca, ZE zemin sınıfı üzerine inşa edilen yapının periyodu Winkler yönteminde %75 daha fazla bulunmuştur. Bu artış deprem kuvvetlerinin artmasına neden olmaktadır. Yapıya etkiyen en büyük ivme sırasıyla ZE, ZD ve ZC zemin sınıfında olmuştur. Ankastre çözümde azaltılmış tasarım ivme değerleri Winkler yöntemine göre çözümden daha fazla olmuştur. Bu sebeple yapı-temel etkileşimini dikkate alan çözüm deprem kuvvetleri açısından daha ekonomik çözüm sunmakta fakat deplasmanlar daha fazla olmaktadır. Perde duvarların yalnız Eğik Çatlama Dayanımı (Vcr) bile deprem kuvvetinin üzerinde kalmaktadır. Bu durum tünel kalıp sistemlerin deprem etkisinde iyi performans göstermesini açıklamaktadır. ZC zemin sınıfında, düşey yükler altında oluşan gerilmeler ZE zemin sınıfına göre %25 daha fazladır. Deprem durumunda ise bu artış %50'ye kadar çıkmaktadır. Buna karşılık oturma değerleri artmaktadır.

An investigation was conducted to assess the efficacy of using waste rubber as a substitute for a portion of an aggregate to enhance concrete’s sustainability. For the purpose of accomplishing this objective, a total of 12 specimens were constructed and then subjected to a series of tests to investigate their bending behavior. The samples were constructed with the following dimensions: 1000 mm length and a 100 mm by 150 mm cross-sectional area. A few factors were selected, including the impacts of the longitudinal reinforcement ratio and the waste rubber ratio. Based on the volume of aggregates, rubber replacement rates of 0%, 5%, 10%, and 15% were investigated in this study. To assess the beam bending behavior, the stirrup width and spacing were kept constant at ∅6/10. The longitudinal reinforcement was composed of three diameters: ∅6 at the top (for all beams) and ∅8, ∅10, and ∅12 at the bottom. The experimental results demonstrated that the effects of varying amounts of waste rubber and tension reinforcement on the bending and cracking of reinforced concrete beams (RCBs) were varied. The findings indicate that the incorporation of waste rubber into concrete results in a reduction in both the load-carrying capacity and the level of deformation of the material. Additionally, it was shown that as the amount of waste rubber in the RCB increased, the energy absorption capacity and ultimate load decreased. There was a reduction in energy dissipation of 53.71%, 51.69%, and 40.55% for ∅8 when longitudinal reinforcement was applied at 5%, 10%, and 15% replacement, respectively. Additionally, there were reductions of 25.35%, 9.31%, and 58.15% for ∅10, and 38.69%, 57.79%, and 62.44% for ∅12, respectively.

The study conducted axial tensile strength tests on concrete samples that replaced conventional aggregates with recycled aggregates. In Series I, using FNG instead of FNA resulted in a reduction in compressive strength by 12.8–49.8% and tensile strength by 14.5–44.6%. If the proportion of FNG exceeds 50%, compressive strength decreases by more than 24.5% and tensile strength by more than 27.5%. In Series II, replacing CNA with CRG reduced compressive and tensile strengths by 18.4–32.8% and 5.1–24.9%, respectively; exceeding 40% CRG results in a compressive strength reduction of more than 32.8% and a tensile strength reduction of more than 24.9%. In Series III, samples made with RCA, CNA, and 20% CRG showed a compressive strength decrease of 8.8–22% and a tensile strength decrease of 10.7–26%; RCA80 samples showed maximum reductions. In Series IV, replacing CNA with RCA resulted in compressive and tensile strength reductions of 15.4–34.7% and 13.9–24.3%, respectively; RCA80 samples again showed maximum reductions. Maximum stress unit deformation values (εo) increased by 3–58.4% in Series I, 9–80% in Series II, 10–44.9% in Series III, and 9–32% in Series IV. Tensile toughness values showed the highest increase of 35.15% in the CRG40 sample and the lowest of 0.13% in the RCA40-20 sample. The use of glass aggregates in concrete is feasible, but exceeding certain ratios can significantly reduce strength. Concrete can effectively use waste glass as a partial substitute for cement, fine aggregates, or as a filler material, potentially enhancing compressive strength.

The growing quantity of tires and building trash piling up in landfills poses a serious threat to the stability of the ecosystem. Researchers are exploring ways to reduce and use such byproducts of the construction industry in an effort to promote greener building practices. Thus, using recycled crumb rubber from scrap tires in concrete manufacturing is important for the industry's long-term viability. This study examines the proportion of waste rubber in fiber form, specifically at weight percentages of 5%, 10%, and 15%. Moreover, the study examines the shear behavior of reinforced concrete beams. A total of twelve RC beam specimens, each sized 100 mm by 150 mm by 1000 mm (w x d x L), were constructed and positioned to the test. Various mixtures were designed with different levels of scrap tire rubber content (0%, 5%, 10%, and 15%) and Stirrup Vol. Ratio (2.10, 2.80, and 3.53) in reinforced concrete beams. The findings indicate that the inclusion of scrap rubber in concrete leads to a decrease in both the mechanical characteristics and weight of the material. This is mostly attributed to the lower strength and stiffness of the rubberized concrete. Furthermore, estimations generated by a variety of design codes were examined alongside the obtained data. In order to make a comparison between the estimates provided by the different codes such as ACI 318-14, CEB-FIB and Iranian national building codes, a calculation was done to determine the ratio of the experimental shear strength to the anticipated shear strength for each code.

In Turkey, a substantial portion of the industrial buildings consists of precast structures. Unfortunately, these buildings suffered significant damage, with some partially collapsing, during two consecutive earthquakes that occurred in Kahramanmaraş (Pazarcık Mw7.7 and Elbistan Mw7.6) on February 6, 2023. Consequently, numerous industrial facilities became unusable, leading to substantial economic losses. This article aims to identify the vulnerabilities of such buildings and assess their actual earthquake performance to prevent potential future damages. The authors collected data through field investigations conducted near the earthquake's epicenter, which were subsequently evaluated within the study. The research comprehensively examines the seismic characteristics of both earthquakes, the structural system of existing prefabricated industrial buildings in the region, and the relevant provisions outlined in the history of earthquake codes for prefabricated industrial buildings. Additionally, nonlinear finite element simulations of the heavily damaged hinged type of column-beam connections commonly employed in earthquake-prone areas are presented. The impact of manufacturing defects on the structural seismic behavior is also investigated. In the study's final stage, it is concluded that non-compliance with structural projects and relevant codes during the manufacture of connection regions in prefabricated industrial buildings is one of the primary causes of structural damage. Furthermore, it is observed that necessary measures should be implemented in these structures to enhance lateral stiffness in the roof plane, and the use of hinged column-beam joints should be avoided or restricted, especially in regions prone to earthquakes. The finite element model analysis reveals that the load-bearing capacity of the connection increases by 62% for lateral out-of-plane loading when grout mortar is applied.

Although Turkey is located in one of the active earthquake belts of the world, the 7.7 and 7.6 magnitude earthquakes that occurred on February 6, 2023, 9 h apart, as rarely seen in the seismology literature, caused one of the biggest disasters in Turkey's history. In the earthquakes affecting an area of approximately 110,000 square kilometers, serious damage and collapse occurred in public buildings as well as other structures. There are more than 12,000 school buildings in the earthquake-affected area and this number constitutes an important part of public buildings. This article deals with the damage types and causes of various public school buildings that were exposed to the earthquakes in southern Turkey on February 6, 2023. The seismicity of the region and the effects of the 6 February earthquakes were discussed, and the response spectra of the different regions most affected by the earthquakes were compared with the design spectra defined in the codes. In addition, during the field investigation the damage types and causes of damage in school buildings were listed in sections and the observations made with performance based analytical studies were supported. From field reconnaissance, the importance of understanding the deficiencies of school buildings, which have social priority, in order to avoid tragic consequences in possible earthquakes has been revealed.

In order to strengthen the reinforced concrete T-beams having insufficient shear strength, several strengthening techniques are available in the literature. In this study, three different strengthening strategies were numerically studied. First one is affixing steel plates to the beam surfaces. Second one includes tightening external steel bars vertically similar to beam stirrups. The last one is simultaneous application of these two strengthening procedures which is particularly proposed in this work. Available experimental test series in the literature were handled in the study. Finite element (FE) models of reinforced concrete beam specimens having sufficient (Beam-1) and low shear capacity (Beam-2) were created within ABAQUS environment. Strengthened beams with different techniques were also modelled to reflect improved shear capacity. FE simulations made it possible to investigate parameters that were not examined during the previous experimental studies. The results of the analyses were then compared and found consistent with the experimentally obtained data. Experimental and FEM analysis results are in agreement between 1% (closest) and 6%. (maximum). Beam-2 was stregthened with 5 new porposed methods. The rate of increase in shear strength varies between 33% and 64%. It was found that, the strengthening techniques were fairly useful in improving the shear capacity of the considered girder. The model with the proposed strengthening alternative has accomplished a higher load carrying capacity, ductility and stiffness than all of the other models.

The settlements occurred in building foundations depend on many soil parameters. Thus, these parameters make the solution both difficult and complex during the calculating process. Therefore, finite element programs use the subgrade reaction coefficient to facilitate the foundation solution. Two different methods, which are Winkler method and Pseudo coupled method, are used in the basic solutions with the coefficient of subgrade reaction. While the Winkler method can be solved with a single field, the pseudo method can be solved with 2 or more fields. In this study, a 10 story building with a 36 m x 36 m square foundation was separately designed on four different sand soils. Two of these soils are classified as C and the others are classified as D according to Eurocode 8. The foundation of this building built on four different soils was divided into six different areas (one region, two regions, three regions, five regions, seven regions, 10 regions). Consequently, 24 analyzes were performed by using the ETABS program. According to the results obtained from these analyzes, while it is appropriate to use the Winkler method in weak sand soils for rigid foundation acceptance, it is more appropriate to use the Pseudo-coupled method in dense sand soils. Pseudo-coupled method should be used in flexible foundation solutions built on weak sand soils. The Winkler method should be used for flexible foundations built on dense sand soils. In the Pseudo-coupled method, the highest settlements were obtained in the two-region solutions. An optimum number of fields was found to be 7 for Pseudo-coupled method.

In January 2017, collapses of the numerous roofs were reported due to excessive snowfall in many provinces of Turkey. In this study, the reasons behind the collapses of the steel roofs of 19 factory buildings were investigated. The steel roofs supported by the precast reinforced concrete columns indicated a similar collapse pattern to each other under the unexpected heavy snow loading. The failure mechanisms of the roofs under the snow loading were simulated numerically. Nonlinear finite element models of a typical industrial building were developed and analyzed under an incremental vertical loading that is identical to snow loading. As a result of the analysis, the vertical load carrying capacity of the roof system and the snow load level causing the collapse of roof were determined. The resulting snow load was compared with the snow load values provided by the code specifications. In addition, the collapse mechanism of the steel roof system was analytically determined and compared with the collapse modes observed in the field and the causes of the failure were evaluated. The failure mechanism and the buckling modes obtained from analyses were found very similar to those observed during the site inspections. The main reasons of the roof failures may be attributed to excessive amount of snow caused by climate change and discrepancy of designed project and as-built project due to lack of building inspection control during the construction of the buildings.

A 6.8-magnitude earthquake that occurred on January 24, 2020, has been effective in Turkey’s eastern regions. The earthquake, with recorded peak ground acceleration (PGA) value of 0.292 g, caused the destruction or heavy damage of buildings, especially in the city center of Elazığ province. The purpose of this paper was to share the results of detailed investigation in the earthquake-stricken area. Additionally, the causes of damages and failures observed in the buildings were compared to those that had occurred in previous earthquakes in Turkey. In this study, the damages observed in especially RC buildings as well as in masonry and rural buildings were summarized, the lessons learned were evaluated, and the results were interpreted with reference to Turkish earthquake codes. In the study, it was particularly emphasized why the building stock underwent such damage even though the buildings were exposed to earthquake acceleration well below the design acceleration values.

In this study, in order to improve the seismic performance of existing reinforced concrete (RC) framed structures, various external attachment of corner steel frame configurations was considered as a user-friendly retrofitting method. The external steel frame is designed to contribute to the lateral stiffness and load carrying capacity of the existing RC structure. A six story building was taken into account. Four different external corner steel frame configurations were suggested in order to strengthen the building. The 3D models of the building with suggested retrofitting steel frames were developed within ABAQUS environment using solid finite elements and analyzed under horizontal loadings nonlinearly. Horizontal top displacement vs loading curves were obtained to determine the overall performance of the building. Contributions of steel and RC frames to the carried loads were computed individually. Load/capacity ratios for the ground floor columns were presented. In the study, 3D rendered images of the building with the suggested retrofits are created to better visualize the real effect of the retrofit on the final appearance of the facade of the building. The analysis results have shown that the proposed external steel frame retrofit configurations increased the lateral load carrying capacity and lateral stiffness and can be used to improve the seismic performance of RC framed buildings.