scholarly journals A Simplified Strengthening Methodology for Minaret Structures in Turkey: Hagia Sophia Case

2017 ◽  
Vol 4 ◽  
pp. 11-17
Author(s):  
Kasım A. Korkmaz
Keyword(s):  
Structural Characteristics ◽  
Research Work ◽  
Time History ◽  
Historical Change ◽  
Main Body ◽  
Historical Structures ◽  
Frp Composites ◽  
Frp Composite ◽  
Before And After ◽  
Hagia Sophia

 Considering various types of historical buildings in Turkey, mosqs are the most common ones. Mosqs have minaret structures standing along next to the main body with dome. The minaret buildings with their own architectural and structural characteristics, are representing the cultural and historical change in different periods over the centruies. Minarets from Ottomon period are the most widespread ones in Turkey. With its cultural synthesis through out the history, minarets from Ottomon period differ from the others with structural capability. Since Turkey is a earthquke prone country, it is very important to make existing historical structures stronger against to the seismic loads. Recently, historical structures have been strengthened with fiber reinforced polymer (FRP) composites. There are numerous of research studies are available related with strengthening using FRP composites. From this standing point, in this research, a simplified and practicale strengthening methodlogy is proposed. For the investigation Hagia Sophia Minaret structures has been used as a case study. In the analysis part, Hagia Sophia Minaret structures have been investigated through time history analyses before and after FRP composite strengthening. As a result of the present research work, displacements and stress values are determined for comparison of the structural behavior of minaret structures.

scholarly journals Dynamic response of masonry minarets strengthened with Fiber Reinforced Polymer (FRP) composites

2011 ◽  
Vol 11 (7) ◽  
pp. 2011-2019 ◽  
Author(s):  
A. C. Altunişik
Keyword(s):  
Dynamic Response ◽  
Cylindrical Body ◽  
Element Model ◽  
Dynamic Responses ◽  
Principal Stresses ◽  
Engineering Structures ◽  
Frp Composites ◽  
Frp Composite ◽  
Before And After ◽  
Historical Masonry

Abstract. Engineering structures strengthened with FRP composites are gaining popularity, and there is a growing need to understand and compare the behavior of these structures before/after FRP composite strengthening. In this paper, it is aimed to determine the dynamic response of masonry minarets before/after FRP composite strengthening. An Iskenderpaşa historical masonry minaret dating back to XVI century with a height of 21 m located in Trabzon, Turkey was selected as an application. Firstly, 3-D finite element model of the minaret was constituted using ANSYS software. Then, an analytical model of the minaret was analyzed using the 1992 Erzincan earthquake record, which occurred near the area, to determine the dynamic behavior. After this, the cylindrical body of the minaret was strengthened with FRP composite using different configurations and dynamic analyses were performed. Finally, dynamic responses of the minaret before and after FRP composite strengthening, such as displacements and maximum-minimum principal stresses, were compared. At the end of the study, it is seen that displacements had increased along the height of the minaret, maximum and minimum principal stresses occur at the region of transition segment and cylindrical body for all analyses. Also, it is seen from the earthquake analyses that FRP strengthening is very effective on the dynamic responses of the minaret.

Design of Fiber-Reinforced Polymer Composite Piles Under Vertical and Lateral Loads

2003 ◽  
Vol 1849 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Jie Han ◽  
J. David Frost ◽  
Vicki L. Brown
Keyword(s):  
Research Work ◽  
Extreme Environments ◽  
Design Methods ◽  
Fiber Reinforced Polymer ◽  
Lateral Loads ◽  
Fiber Reinforced ◽  
Frp Composites ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Current Design

Conventional pile materials, such as steel, concrete, and wood, can encounter serious corrosion problems in industrial and marine environments. Deterioration of steel, concrete, and wood piling systems has cost the military and civilian marine and waterfront civil engineering communities billions of dollars to repair and replace. Fiber-reinforced polymer (FRP) composites have desirable properties for extreme environments because they are noncorrosive, nonconductive, and lightweight. Different types of FRP composite piles are currently under research investigation, and some have been introduced to the marketplace. FRP composites have been used as internal reinforcement in concrete piles; as external shells for steel, concrete, and timber piles; and as structural piles such as FRP pipe piles, reinforced plastic piles, and plastic fender piles. The different ways of constituting FRP composite piles result in different behavioral effects. Because FRP structural piles have anisotropic properties, low section stiffness, and high ratios of elastic to shear modulus, they have different behavior in load-displacement relations under vertical and lateral loads. Current design methods for conventional piles were examined to determine the validity for FRP composite piles, and some new design methods specific to FRP structural piles were developed from research work conducted by the authors.

scholarly journals Evaluation of cerebrovascular hemodynamics in patients with idiopathic intracranial hypertension using transcranial Doppler

2020 ◽  
Vol 56 (1) ◽  
Author(s):  
Mahmoud M. Allam ◽  
Hatem A. Almasry ◽  
Sandra M. Ahmed ◽  
Youssuf G. Taha ◽  
Mohammed I. Oraby
Keyword(s):  
Intracranial Pressure ◽  
Intracranial Hypertension ◽  
Lumbar Puncture ◽  
Transcranial Doppler ◽  
Idiopathic Intracranial Hypertension ◽  
Pulsatility Index ◽  
Research Work ◽  
Increased Intracranial Pressure ◽  
Significant Relation ◽  
Before And After

Abstract Background Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial pressure without a clear cause and can have serious visual effects. Previous research work suggests that transcranial Doppler measurements of pulsatility index correlate accurately with elevated intracranial pressure. Objective To assess the cerebrovascular hemodynamic changes in patients with IIH using transcranial Doppler before and after lumbar puncture and CSF withdrawal. Methods An interventional study conducted on 40 patients (31 females and 9 males) fulfilling the modified Dandy criteria for diagnosis of idiopathic intracranial hypertension, MRI brain, and MRV was done to the patients. Lumbar puncture was done for all included patients to measure intracranial pressure and CSF withdrawal. Transcranial Doppler was performed for all included before and after lumbar puncture and CSF withdrawal and the following parameters were measured: peak systolic velocity (PSV), end diastolic velocity (EDV), resistivity index (RI), and pulsatility index (PI). Results Significant relation was found between grades of papilledema and PSV, RI, and PI (p value 0.012, 0.025, 0.016) but no significant relation was found between grades of papilledema and EDV (0.102). Significant changes occurred in parameters of TCD pre- and post-CSF withdrawal including PSV, EDV, and PI (p value 0.001, 0.015, 0.019) denoting a significant change in cerebral hemodynamics after CSF withdrawal which denotes a decrease in intracranial pressure. Conclusion Increased intracranial pressure significantly affects cerebral blood flow. A normalization of transcranial Doppler parameters occurs following lowering of intracranial pressure through lumbar puncture and CSF withdrawal.

scholarly journals Physicochemical and structural characteristics of HEU-type zeolitic tuff treated by hydrochloric acid

2004 ◽  
Vol 69 (4) ◽  
pp. 273-282 ◽  
Author(s):  
Ana Radosavljevic-Mihajlovic ◽  
Vera Dondur ◽  
Aleksandra Dakovic ◽  
Jovan Lemic ◽  
Magdalena Tomasevic-Canovic
Keyword(s):  
Crystal Structure ◽  
Hydrochloric Acid ◽  
Bosnia And Herzegovina ◽  
Acid Treatment ◽  
Structural Characteristics ◽  
Chemical Analyses ◽  
Zeolitic Tuff ◽  
Zeolitic Tuffs ◽  
Before And After

Samples of natural HEU-type zeolites ? clinoptilolite-Ca, from the Novakovici deposit (near Prijedor, Bosnia and Herzegovina) were treated with the hydrochloric acid of various concentrations (from 10-3Mto 2M). Zeolitic tuffs before and after the acid treatment were examined using IR, XRPD, and chemical analyses. The changes in the crystal structure of acid treated samples showed a significant reduction in the crystallinity of zeolitic tuffs (60?70 %), which were effected by hydrochloric acid with concentrations of 1 M and above.

Aortic endograft and bridging stent-graft remodeling after branched endovascular aortic repair

Vascular ◽  
2020 ◽  
pp. 170853812098369
Author(s):  
Stefano Fazzini ◽  
Giovanni Torsello ◽  
Martin Austermann ◽  
Efthymios Beropoulis ◽  
Roberta Munaò ◽  
...  
Keyword(s):  
Stent Graft ◽  
Endovascular Repair ◽  
Main Body ◽  
Thoracoabdominal Aneurysm ◽  
Before And After ◽  
Long Term Follow Up ◽  
Instability Rate ◽  
One Year ◽  
The Impact

Objectives The results of branched endovascular repair of thoracoabdominal aneurysms are mainly dependent on durability of the graft used. The purpose of this study was to evaluate postoperative aortic main body and bridging stent-graft remodeling, and their impact on bridging stent-graft instability at one year. Methods Computed tomoangiographies of 43 patients (43 aortic main body mated with 171 bridging stent-grafts) were analyzed before and after branched endovascular repair as well as after a follow-up of 12 months. Primary endpoint was aortic main body remodeling (migration >5 mm, shortening >5 mm, scoliosis >5° or lordosis >5°). Shortening was defined as a reduced length in the long axis, scoliosis as left-right curvature, and lordosis as antero-posterior curvature. Aortic main body remodeling, aneurysm sac changes, and bridging stent-graft tortuosity were evaluated to study their correlations and the impact on the bridging stent-graft instability. Results At 12 months, aortic main body remodeling was observed in 72% of the cases, migration in 39.5% (mean 5.21 mm), shortening in 41.9% (mean 5.79 mm), scoliosis in 58.1%, (mean 10.10°), lordosis in 44.2% (mean 5.78°). Migration, shortening, and scoliosis were more frequent in patients with larger aneurysms ( p = .005), while scoliosis was significantly more frequent in type II thoracoabdominal aneurysm ( p = .019). Aortic main body remodeling was significantly associated to bridging stent-graft remodeling (r: 0.3–0.48). The bridging stent-graft instability rate was 9.3%. Despite a trend toward significance ( p = .07), none of the evaluated aortic main body and bridging stent-graft changes were associated with bridging stent-graft instability at 12 months. Conclusions Aortic main body remodeling is frequent especially in large and extended thoracoabdominal aneurysm aneurysms. Aortic main body and bridging stent-graft remodeling was significantly correlated. While these geometric changes had no significant impact on bridging stent-graft instability at one year, a close long-term follow-up after branched endovascular repair could predict bridging stent-graft failures.

Structural Performance of Automated Multi-Depth Shuttle Warehouses (Amsws) Under Low-to-Moderate Seismic Actions

2021 ◽  
Author(s):  
Aleksei Kondratenko ◽  
Alper Kanyilmaz ◽  
Carlo Andrea Castiglioni ◽  
Francesco Morelli ◽  
Mohsen Kohrangi
Keyword(s):  
Seismic Design ◽  
Brittle Failure ◽  
Structural Characteristics ◽  
Time History ◽  
Steel Structures ◽  
Current Approach ◽  
Structural Performance ◽  
Future Design ◽  
The Future ◽  
Base Connections

Abstract Automated Multi-Depth Shuttle Warehouses (AMSWs) are compact storage systems that provide a large surface occupation and therefore maximum storage density. AMSWs represent the future of storage technology, providing substantial savings in terms of cost, space, and energy with respect to traditional warehouses. Currently, designers refer to the standard building codes for the seismic design of AMSWs. Since structural characteristics of AMSWs are considerably different from the steel structures of typical buildings, this current approach used by designers is questionable in terms of safety and efficiency. In this article, the behavior of 5 AMSW structures has been studied performing 150 time-history analyses by direct integration including P-Delta effects. Demand/capacity ratios calculated for each element showed the dominance of the brittle failure mechanism in AMSWs subjected to low-to-moderate seismic actions. These mechanisms mainly took place in upright columns and their base connections prior to the activation of ductile energy dissipation mechanisms of the structure. Based on the results, further improvements have been recommended for the future design provisions, which may lead to a safer seismic design of AMSWs.

The all-composite road bridge – a proposal for rapid urbanisation

2018 ◽  
Author(s):  
Tomasz Siwowski ◽  
Aleksander Kozlowski ◽  
Leonard Ziemiański ◽  
Mateusz Rajchel ◽  
Damian Kaleta
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Construction Materials ◽  
Fast Growing ◽  
Frp Composites ◽  
Frp Composite ◽  
Reinforced Polymer ◽  
Composite Bridge ◽  
Fibre Reinforced Polymer ◽  
Traditional Construction

<p>Technology and materials can help cities get smarter and cope with rapid urbanisation. Life cycle assessment (LCA) is one of the approaches applied in evaluation of material sustainability. Many significant LCA comparisons of innovative and traditional construction materials indicate that fibre- reinforced polymer (FRP) composites compare very favourably with other materials studied. As a proposal for rapid urbanisation, the FRP all-composite road bridge was developed and demonstrated in Poland. The paper describes the bridge system itself and presents the results of research on its development. The output of the R&amp;D project gives a very promising future for the FRP composite bridge application in Poland, especially for cleaner, resilient and more environmentally efficient infrastructure of fast-growing cities.</p>

MEASURES FOR IMPROVING THE MICROBIOLOGICAL SAFETY OF COW MILK

2019 ◽  
Vol 1 (1) ◽  
pp. 44-49
Author(s):  
G. A. Larionov ◽  
◽  
O. Yu. Checheneshkina ◽  
N. V. Mardaryeva ◽  
N. V. Sсhiptsova ◽  
...  
Keyword(s):  
Somatic Cells ◽  
Research Work ◽  
Dairy Farm ◽  
Cow Milk ◽  
Control Group ◽  
Anaerobic Microorganisms ◽  
Special Means ◽  
Before And After ◽  
Processing Enterprise

Safety of milk on microbiological indicators is an important condition for acceptance on the milk processing enterprise. High microbial contamination of milk and increased content of somatic cells in milk are often the cause of discrepancy to modern requirements of national and international regulatory documents. The development and implementation of measures aimed at improving the condition of the udder of cows, the use of modern means of processing is one of the most important tasks to improve the sanitary and hygienic conditions of milk production. Prevention of mastitis is one of the effective ways to improve the safety and quality of cows' milk. It is known that the most affordable way to prevent mastitis is strict hygiene during milking. In our article the results of research work received in the conditions of a dairy farm are presented. Researches on use of modern domestic means of processing of an udder before and after milking are carried out. For this, two experimental and one control groups were created. In summer and autumn, the udder of cows in the experimental groups were treated with special detergents and disinfectants. In the control group, the udders were not treated with special means. Udder hygiene was maintained by washing the nipples with warm water, as is customary in the household. It was established that the treatment of the udder of cows with disinfectants decreased the number of mesophilic aerobic and facultatively anaerobic microorganisms and somatic cells in the milk of cows.

Aanalysis of springback phenomenon in pipe bending

2014 ◽  
Vol 11 (3) ◽  
pp. 229-232
Author(s):  
Rahul Hingole ◽  
Vilas Nandedkar
Keyword(s):  
Sheet Metal ◽  
Research Work ◽  
Deep Understanding ◽  
Beam Theory ◽  
New Approach ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Before And After ◽  
Forming Tools ◽  
Pipe Bending

The term springback is defined as the change in geometry of a component after forming, when the forces are removed from forming tools. As springback affects the final shape of the part, it can lead to significant difficulties in the assembly of component when springback is not proper. This problem leads to fabrication of inconsistent sheet metal parts; the elastic strain recovery in the material after the tooling is removed. Bendingis the plastic deformation of metals about a linear axis called the bending axis with little or no change in the surface area. Bending types of forming operations have been used widely in sheet metal forming industries to produce structural stamping parts such as braces, brackets, supports, hinges, angles, frames, channel and other nonsymmetrical sheet metal parts. Among them, quite a few efforts have been made to obtain a deep understanding of the springback phenomenon. The beam theory has been applied to formulate the curvature before and after loading of pipe. This research work has focused on study effect of springback effect with a new approach. The ANSYS software is used to analyze spring back effect. The detail study of this springback effect is presented in this paper.

Nonlinear Structural Damage Detection Based on Adaptive Volterra Filter Model

2018 ◽  
Vol 18 (02) ◽  
pp. 1871003 ◽  
Author(s):  
J. Prawin ◽  
A. Rama Mohan Rao
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Linear Models ◽  
Time History ◽  
Diagnostic Techniques ◽  
Filter Model ◽  
Volterra Filter ◽  
Damage Indices ◽  
Before And After ◽  
Nonlinear Time History

The majority of the existing damage diagnostic techniques are based on linear models. Changes in the state of the dynamics of these models, before and after damage in the structure based on the vibration measurements, are popularly used as damage indicators. However, the system may initially behave linearly and subsequently exhibit nonlinearity due to the incipience of damage. Breathing cracks that exhibit bilinear behavior are one such example of the damage induced due to nonlinearity. Further many real world structures even in their undamaged state are nonlinear. Hence, in this paper, we present a nonlinear damage detection technique based on the adaptive Volterra filter using the nonlinear time history response. Three damage indices based on the adaptive Volterra filter are proposed and their sensitiveness to damage and noise is assessed through two numerically simulated examples. Numerical investigations demonstrate the effectiveness of the adaptive Volterra filter model to detect damage in nonlinear structures even with measurement noise.

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