Theses supervised by Prof. Dr. Mustafa Günal
32 theses · Gaziantep University
Evaluation of the impact of nanomaterial on local scour around bridge piers
Bridges are a vital element of the infrastructure of a country. There are many reasons that lead to bridge piers failure and scour is one of the most problems against the bridges, moreover localized scour combined with general riverbed degradation, and therefore it's important to improve the soil under the piers. Several methods can be used to improve the soil under the bridge piers. Three dimensional numerical scour modeling was developed to simulate the local scour around bridge piers under using of Nano clay technique using finite difference method ANSYS FLUENT software. In this study Nano Clay was used to reduce the maximum local scour depth around circular bridge piers. Three different bridge pier diameters were used with different percentages of Nano clay of 0, 3, 5, 10, 13, 17, 20 and 25 respectively in the sand. The effect of Nano clay on local scour was investigated at different percentage as scenario in the mixture of sand around bridge pier. The model depending on experimental data started with zero percentage of Nano clay as scenario (sc1). In this scenario, the maximum local scour has been high. Addition of Nano clay reduced the maximum local scour. The simulation results show that the maximum scour depth changes with diameter of pier and the percentages of Nano clay. The optimum percentage of Nano clay in the mixture of sand was found as 13% which is scenario 5 (sc.5), where the maximum local scour for pier diameter of 11.1 cm reduced by 1.60 cm compered to scenario 1 (sc1).
Numerical study of countermeasures against the local scour around bridge pier using flow-3D software
Scour is one of the most protruding factors in bridge failures worldwide. Investigating the causes of scouring will offer a view of the solution probabilities. Countermeasure methods attached to the bridge piers greatly influence reducing the local scour, mainly when it deflects water and weakens the vortices that affect the bed sediment around the pier. In this study, Flow-3D was used to simulate the three-dimensional model to investigate local scouring around the pier, after controlling and ensuring by calibrating the model using a single-circular pier model in FLOW 3D with a circular pier from an experimental study was carried out by Adnan et al., 2015 in the same conditions. The purpose of this study is to examine the performance and the reflection of adding two countermeasures by CFD modeling, namely collar and slot, in the reduction of scour depth around the bridge pier. In the first scenario, four cases slot were used, namely (UHS, MHS, LHS, FWD) respectively. The second scenario circular types of collars attached to the pier added to a pier with two collars diameter at the bed sediment were 20 and 30 cm for CAB-2Dp and CAB-3Dp. Finally, the best-case of previous scenarios compound FWD & CAB-3Dp were analyzed. Adding a collar and slot has significantly reduced local scour around the pier. The collars act more useful than a slot in terms of controlling and weakening the downflow, also lowering the scour depth around the pier. When combining both FWDS and CAB-3D cases, the scour was eliminated in the front and rear of the pier, also noted an increase in the reduction percentage, reaching 56% compared with the exact location on the reference models.
Numerical analysis of local scour downstream of a spillway
The Ogee crested spillway has become one of the most researched hydraulic structures due to its excellent hydraulic features and versatility, Generally hydraulic structures are always subject to scouring effects within and around their foundations or downstream of the spillway. In an attempt to improve upon the evaluation of scouring characteristics downstream of the spillway an Ogee spillway, this experiment aims to explain the numerical simulation of an already existing physical experimental set up that evaluated scouring characteristics in terms of scouring depth and scouring length, taking into consideration the flowrate, tail water depth and bed material as the fundamental independent variables. Thus, the experiment was conducted was virtually as model within the Flow3D computer software, results were obtained and then compared to that of the physical experiment. According to the scouring results acquired from the CFD numerical simulation, the scouring characteristics clearly notably increased the downstream of the spillway, discharge flow rate and tail water depth, The size and shape of bed materials also have a considerable impact on local scouring of the downstream of the spillway. More scouring is typically results from bed materials with a smaller diameter than by that of a larger diameter. The results of this investigation have produced numerical figures that are accurate in estimation and within close acceptable boundaries when compared to the physical experimental study it was based on.
Flood risk assessment using GIS tools
Floods' worldwide consequences have increased in recent years due to their enormous strain on the environment, exposed people, and associated losses of life and economic devastation. Floods have become more damaging as a result of a variety of circumstances, including increasing construction on flood plains. In recent years, there has been a lot of interest in employing GIS applications to evaluate flooding susceptibility. In this thesis, we examine the use of GIS in flood assessment along the Orontes (Asi) River in Syria. Land use, slope, elevation, and building size are ranked according to their physical contribution to flood-related change in an assessment of flood vulnerability. The goal is to draw attention to places that will likely be severely affected by river flooding. It should be noted that this research just takes into account the assumption of water depth. Therefore a more in-depth hydraulic and hydrologic analysis of the flooding in the whole region would be preferable for a complete picture. The results showed that areas near the Orontes River in Syria are in danger of flooding, particularly the mountainous and urban/barren areas. Building sections inside the basin, which enable water to move quickly, are particularly at risk of flooding.
Investigations the effect of slot on scour depth reductions around bridge piers
The scouring of sediments around bridge foundations leading to collapses remains a significant problem, causing both economic losses and risking human lives. The scouring of sediments around bridge foundations leading to collapses is the Morandi Bridge in Genoa, Italy. In August 2018, the bridge suffered a catastrophic failure due to severe scouring of its foundations caused by heavy rainfall. Researchers have been actively studying these phenomena and seeking effective measures to mitigate the impacts of scour around bridge elements. This study focuses on investigating the impact of incorporating slot through the bridge pier as a countermeasure to reduce scour depth using the Flow 3D software. Scour reduction solutions for bridge piers can be broadly categorized into flow-altering countermeasures and bed-armoring countermeasures. Flow-altering countermeasures aim to weaken the down-flow and horseshoe vortex, which are the main contributors to pier scour. This study specifically examines the effectiveness of different slot shapes introduced through the bridge pier as countermeasure methods. By employing various models and a reference model, the study evaluates the reduction in local scour depth achieved by the different slot configurations. The results obtained from comparing the various models will determine the optimal percentage of local scour reduction achievable using the proposed countermeasure methods.
Numerical study of local scour around bridge pier with collar using flow-3D software
The scouring of sediments around bridge foundations in the riverbed leading to collapse remains a significant problem, causing both economic losses and risking human lives. This investigation focuses on studying the effects of collar for reducing scour around bridge piers by using two different types of bridge pier shapes namely circular and nosed pier. In recent years, three-dimensional simulation methods for scouring have gained popularity due to advancements in computer capabilities and software, enabling the widespread utilization of Computational Fluid Dynamics (CFD) to analyze scour phenomena in various industrial and environmental applications. A numerical model is created for bridge pier with collar to compare and validate the results obtained from the experimental study of Ismael A. et al., in 2015. Findings shows that local scour is reduced by using collared bridge pier.
Numerical study of local scour downstream of sluice gate
The persistent local scour downstream of the apron poses a serious threat to the stability of hydraulic structures, as it exposes their foundations to erosion factors. The turbulent flow impact emitted under the sluice gate can significantly contribute to the failure of the hydraulic structure. Therefore, comprehensive examination test of scouring becomes essential in order to fully understand of scour phenomenon and develop a suitable remedial strategy. In this study, experimental study of local scour downstream of sluice gate done by Ahmad (2017) is simulated with Flow-3D. The numerical model is done for three sediment bed diameters of 0.27, 2.67 and 6.68 mm and three discharge of 0.05m3/s for case A and 0.08 m3/s for case B and C using different tail water depth and densimetric Froude number. After performing numerical simulations, the results showed that the numerical results were close to the experimental results. Then triangle, rectangle and trapezoidal shape of baffle blocks were designed on the apron to reduce the local scour and the maximum local scour values were compared to each other and decided the best shape of the baffle blocks.
EVALUATION OF FLOOD ANALYSIS UTILIZING THE HEC-RAS MODEL
Syria faces a spectrum of natural hazards, encompassing drought and desertification and recurring instances of floods. One poignant incident illustrating this vulnerability occurred in February 2015, when a family of four tragically drowned following the flooding of the Al Kabeer Al Shemali River in Latakia. This flood event inundated citrus groves and greenhouses on both sides of the river course. The research is investigating flow behaviour during flooding in the Al Kabeer Al Shemali River in Latakia, Syria, and developing inundation maps based on various probability scenarios (for three specific recurrence intervals and three different water elevation scenarios) utilizing the HEC-RAS software. The inundation spaces were identified using Geographic Information System (GIS) tools, along with Digital Elevation Models (DEM) for contour lines. The findings indicated that the agricultural sector and urban facilities on the river are highly vulnerable to the impact of flooding, suggesting that the river is prone to flood hazards. Furthermore, the results indicated that inundated areas increase with the rise in the expected maximum values of flood intensity according to various assumed return periods.
Numerical modeling of local scour around circular bridge piers arranged in a triangular configuration
Bridge piers are essential structural elements that support bridges over water bodies. however, their exposure to hydrodynamic forces makes them exposed to local scour and corrosion. local scour, caused by the removal of sediment around bridge piers due to water flow, weakens the foundation and can lead to structural instability. understanding the interaction between hydrodynamic forces, scour mechanisms, and corrosion effects is crucial for designing durable bridge foundations. This study aims to investigate the local scour around a triangular group of circular bridge piers. by simulating (flow field, sediment transport, and corrosion processes) the study will provide evaluating the effects of local scour on the stability of circular bridge piers in a triangular configuration also, to give an insight into the mechanisms affecting bridge pier stability. Additionally, to propose effective mitigation strategies. This study will contribute to the field of hydraulic engineering by providing a detailed analysis of scouring processes using FLOW-3D software. The findings will help in designing more resilient bridge foundations and reduce potential failures due to hydrodynamic forces and material degradation. Key Words: Local scour, Bridge piers, Numerical modeling, FLOW-3D, Hydrodynamic forces
Suriye'nin rakka valiliğinde kuraklık değerlendirmesi ve izleme çalışması
İklim değişikliğinin en ciddi etkilerinden biri olan kuraklık, özellikle Ar-Rakka (Suriye) gibi çatışmadan etkilenen tarımsal bölgelerde önemli bir sorun olmaya devam etmektedir. Bu çalışma, istatistiksel ve CBS tabanlı yöntemlerle desteklenen uydu kaynaklı yağış ve vejetasyon göstergelerini kullanarak kuraklık dinamiklerini ve bitki örtüsünün tepkisini analiz etmektedir. CHIRPS aylık yağış verileri (1981–2024) SPI3 hesaplamasında, MODIS NDVI verileri (2002–2024) ise bitki sağlığının değerlendirilmesinde kullanılmıştır. Ön-arındırma uygulanarak yürütülen Mann– Kendall ve Sen eğim testleri, yıllık değişkenliğe rağmen yağış veya vejetasyon yeşilliğinde uzun vadeli anlamlı bir eğilim göstermemiştir. Çapraz korelasyon analizi, NDVI'nın yağışa bir ila üç ay gecikmeli tepki verdiğini ortaya koymuştur. VCI ve VHI analizleri, 2019'daki nemli koşullar ile 2021'deki şiddetli kuraklık arasında belirgin farklarla güçlü mekânsal heterojenlik göstermiştir. Gecikmeli SPI ve NDVI değerleri, kısa vadeli kuraklık tahmini için Random Forest ve XGBoost modellerinde kullanılmış ve bu modeller orta düzeyde tahmin başarısı sağlamış; daha yüksek doğruluk için ek iklim değişkenlerinin gerekliliğini vurgulamıştır. Bu çalışma, kurak ve yarı kurak bölgelerde erken uyarı sistemlerini ve sürdürülebilir su-arazi yönetimini desteklemek için bölgeye özgü kanıtlar sunmaktadır. Anahtar Kelimeler: Kuraklık izleme, Uzaktan algılama, SPI, NDVI, İklim değişikliği
Dam modeling and simulation of flow through bottom outlets
The main objective of this study is to create computational model for the large scale repulse dam called Badush dam by using three advanced techniques; computational fluid dynamics, geographical information systems, and computer-aided design. These techniques can manage to integrate and interact in order to enable engineers and researchers to evaluate flow characteristics accurately and make some technical decisions related to modification in design and improvement in performance. The quality of the digital terrain model and stereo-lithographic data has a significant role in the accuracy of the created computational model and its performance. In this study, digital elevation model with 11 m resolution for hydraulic calculations and 30m resolution for hydrologic calculations were used. Besides, the use of accurate stereo-lithographic with zero bad edges has made a development in representing the geometric shape of the large scale dam. In this study, design flood level and normal water level at the upstream of the concrete dam structure were modified, which they already calculated through the physical model as well. Also, comparison between computational model and physical model through the measurements of flow characteristics are performed. The results show that the obtained measurements are close to each other in both cases. This proves the validation and efficiency of the designed computational model for assessing physical model and performing additional related studies. In accordance with this study, geomorphologic analysis and flood plain analysis based on the digital terrain model are performed effectively and accurately.
Design of road-crossing drainage culverts using GIS data
The rational method and the computer aided GIS methods are used to make the box culvert size analysis. The General Directorate of Highways uses the rational method for dimensional analysis. In this study, A box culvert analysis was performedin cities located between Gaziantep and Yavuzeli-Araban districts located in 37°30'33.00"N 37°42'18.19"E. A rational and computer assisted ArcGIS program was used for size analysis. The results obtained by both methods were compared. The 10 year and 100 year maximum loads from the Gaziantep Regional Directorate of Meteorology for the study area were obtained graphically based on time. The soil permeability coefficient (c) is calculated based on the results of the study in a region close to the basin. The properties of the box culvert were calculated and dimensioned using the 10-year and 100-year maximum deflections using GIS program. At the end of the study, different sections were obtained from the rational method which is used by the General Directorate of Highways and the dimension analysis using ArcGIS program. It has been observed that more realistic results are obtained with the ArcGIS program
Engineering properties of pervious concretes produced with recycled aggregate at different aggregate-to-cement ratio
The aim of this study was to obtain engineering properties of the pervious concrete produced with recycled coarse aggregate at different aggregate-to-cement ratio (a/c) and inclusion of 5% (by weight of total aggregate) of both natural and recycled fine aggregate to make a very sustainable concrete product for many applications. The research methodology concerned production pervious concrete with recycled aggregate at 3 different aggregate-to-cement ratios 6, 5, and 4. The water-to-cement ratio (w/c) was kept constant at 0.3. Single sized recycled coarse aggregate, passing from 12.5-mm sieve and retained on 9.5-mm sieve with both natural and recycled sand, passing from 4-mm sieve were used in the making of pervious concrete. Totally twelve different concrete mixtures were produced and each of the concrete samples was tested for dry density, porosity, compressive and splitting tensile strength, water permeability and abrasion resistance. The experimental results indicated that reducing aggregate-to-cement ratio improves overall performance of the pervious concrete, also adding a small amount of fine aggregate increase mechanical strengths and decrease void content and permeability.
Modeling scouring around bridge piers with different geometries
Scouring around bridge pier considered as one of the main reasons of bridge failure. Failure of the bridge structure is a catastrophic phenomenon. Studying the causes of scouring will give an idea about the solution probabilities, the shape and geometry of bridge piers has a great influence on the local scour. A literature review showed that there is still a lack of experimental and numerical investigation on the influence of the non-uniform pier geometry. Flow-3D was used for simulating of three-dimensional model to study local scouring around three different models of bridge piers based on an experimental study from literature which is performed to study the probability of reducing local scouring around a three different bridge pier models, one circular model and two non-uniform pier shapes with different orientations of bridge piers named as "upstream-facing round nosed pier (US-FRNP) (10-4)cm" and "downstream-facing round nosed pier (DS-FRNP) (4-10)cm" according to flow direction in a fixed flatbed and scoured bed condition. The results showed a good agreement between the experimental and numerical models and result from comparisons from both studies reveal that "downstream facing round-nosed bridge pier (DS-FRNP)" is an efficient countermeasure to lessen both scour depth and volume.
Simulation of local scouring downstream of broad crested weirs with variable step angles
Broad crested weirs are hydraulic structures used to control the flow depth and discharge of channels. Structures constructed in rivers and channels are exposed to scour around their foundations as they cause turbulences in uniform flow and sediment transport as a result of increase in flow velocities at downstream. If the scour depth becomes substantial the stability of the foundations endangered with a resultant hazard to the structural failure. In this study the flow field variation and the corresponding scour depth was simulated using three-dimensional hydrodynamic analysis and a bed-load transport model by Flow-3D software. The bed-load transport model in Flow-3D is able to simulate the scour hole development. Four models of perforated hump Step Broad Crested Weirs [A, B, C, D] with different downstream reverse angles (0.0, 4.50, 8.70 ,13.0) respectively are tested under the same flow intensity and the same duration of 6 hours. There was a good agreement between experimental and Flow-3D results. The results showed that, model C reduces local scour hole volume and the maximum depth of scour and also shift the scour holes away from the structure as compared to the other models. The present technique similarly reduces costs and improves the hydraulic performance of broad crested weirs
Development of optimal deflection hardening cementitious composites mixture for highway bridge decks to address shrinkage cracking problem
The bridge deck concrete tends to crack more than other concrete structures due to shrinkage. This behavior is attributed to the fact that the shrinkage increases whenever the surface to-volume ratio increases. The production of High Performance Fiber Reinforced Concretes (HPFRC) based on a maximal amount of coarse aggregates and increasing use of industrial by-products (without sacrificing the deflection-hardening behavior) is the purpose of present study to contribute enhancing the mechanical and durability performance with increasing the cracking resistance. After a preliminary study, 24 HPFRC mixtures with a maximum aggregate size of 12 mm were developed with maximal variation in coarse aggregate contents without compromising deflection-hardening behavior. Three different fibers were used at a maximum of 2% of volume in single or hybrid systems: polyvinyl-alcohol (P), hooked-end steel (S) and nylo-mono (N) fibers. To function synergistically with different fiber types and high amounts of coarse aggregates, matrix properties were optimized by varying the proportions of fly ash to Portland cement (FA/PC ratios of 0.20, 0.45, and 0.70, by weight) and aggregate to binder (A/B ratios of 1.0, 1.5, and 2.0, by weight). The produced HPFRC mixtures were evaluated to find their performances under different tests such as bending, compression, free and restrained shrinkage, impact, slab panel, and freezing- thawing tests. Based on the obtained results from the above performed tests, all of produced mixtures were ranked depending on the performances rank analysis. The results revealed that, the overall mixtures' performance was clearly increased as mixtures having three types of fibers (i.e. hybrid fiber system with three types of fibers). The increasing trend in mixtures' performance was improved throughout increasing the A/B ratios especially at A/B ratio of 2.0. Keywords: Deflection-hardening; HPFRC; Cracking Resistance; Coarse Aggregates; Impact Resistance; Energy Absorption.
Investigation of local scour and discharge characteristics of single step broad crested weirs
Scour control process considered as the main objective to ensure safety and economical design of hydraulic structures to prevent any serious failure in the future. Many types of research showed that local scour downstream of single step broad crested weir decreased five times in comparison with a traditional weir. In this study single step broad crested weir with height (21) cm at downstream and ten models of them are investigated. The first group is four models of ramps with different angles at the downstream of weir and six models of hollow end sill with different heights and porosity. The measurements were tested under three discharges for a duration of 6 hours, and the velocity field was measured by using an Acoustic Doppler Velocimeter. The present results showed that the ramp with an angle (10.80) is the best model to decrease local scour hole volume and a maximum depth of scour. It is also found that the end sill with height (24) cm and porosity (35%) give a low local scour hole volume and maximum depth of scour. The minimum distance of scour from weir is an important issue to prevent failure of weir in the future. In this research, the single broad crested weir was modified to produce minimum local scour at downstream and also reduces costs because there is no need to use countermeasures for reducing the scour depth by lining with rubbles and riprap to protect failure.
Design of nano-modified cementitious composites for bridge deck application
Unlike conventional concrete, the material design process for Engineered Cementitious Composites (ECC) involves micromechanics-based design theory, paving the way for the use of high volumes of fly ash (HVFA) as a major component. Using high volumes of fly ash (up to 85% weight fraction of cement) in ECC mixtures enables improved tensile ductility (approximately a 3% increase in long-term tensile strain) with reduced crack widths, although it also leads to significantly reduced early-age compressive and tensile strength and chloride ion resistance. However, nano-mineral additives are known to improve mechanical strength and durability of HVFA systems. In this sense, within the scope of present thesis emphasis was firstly placed on the utilization of different nano-mineral additives in HVFA ECC production to tailor the basic mechanical properties of the mixtures. Secondly, focus was placed on the effects of different Class-F fly ash/cement ratios on hydration properties and microstructural characteristics, transport and mechanical properties of ECC mixtures designed with different mineral additives. Experimental results confirm that nano-additives could significantly improve both flexural strength and ductility of ECC, especially at early ages. Although different optimum levels can be selected to favor various ECC properties; optimum weight fraction of FA (fly ash) is dependent on the mechanism of nano-modification (i.e. type of modifier).
Prediction of local scour downstream of singlestep broad crested porous weirs
Broad crested weirs are hydraulic structures used for flow measurement and water level regulator. In hydraulic structures which are obstacles to flow, the differences in flow pattern in some areas result local scour in these areas. Scour is the bed erosion at the downstream of the hydraulic structures due to high water flow or turbulent flow. The importance of examining the scour depth is evident when the scour depth is significant on river structure's foundation and affecting the stability of the structures or destroying them. In this study, flow was simulated using three –dimensional hydrodynamic analysis by FLOW-3D software and maximum depth downstream of the weir was predicted. Three models of Single Step Broad Crested Weirs [C1, C2, C3] with same step angles (8.7) and different porosities (20,25,30%) and different discharges (15,20,25) l/s respectively are tested under the same duration of 6 hours. There was a good agreement between experimental and FLOW-3D results. The numerical and the experimental results showed that, model C3 reduce the maximum depth of scour and also dump the scour holes away from the structure as compared to other models. The numerical study showed that the value of the scour depth at the downstream of the weir increased by increasing the discharge. The porosity effect was also studied in the scour depth at the downstream of the weir. It has been found that model C3 and porosity (30%) give a minimum scour depth and minimum local scour hole volume. The present technique reduces costs and improves the hydraulic performance of the broad crested weir.
Investigation of effect of intermediate sill on local scouring at the end of stilling basin
In this study, a three-dimensional numerical model of sediment was simulated based on previous experimental work. The simulation was performed by using Flow-3D software the Renormalized Group (RNG) k-ε turbulence model was chosen in the numerical modeling. The scour process was calculated at the end of the USBR type VI stilling basin with impact wall, end sill and intermediate sill. To investigate the effect of intermediate sill geometry on the local scour depth, four different intermediate sill geometry were used and maximum scour depth for each model was simulated at the end of stilling basin to select the best type of intermediate sill that reduces the scouring to a minimum value. To assess the precision of the CFD program the numerical results will be compared with experimental. After the simulation, the results showed that the numerical results close to the experimental, but only had the high difference in model-5. Results showed that intermediate sill has a great effect on the scour depth at the end of the stilling basin, it has a clear difference between the results of scour depth for stilling basin with and without intermediate sill and their effects depend on it is geometry, the results showed that the minimum scour depth occurred in the square intermediate sill.
Simulation of local scour around a group of bridge pier using flow-3D software
Computational Fluid Dynamics is one of the effective methods to study various hydraulic problems as it saves cost, turnaround time and procures reliable results. It is applied for resolving different fluid flow related problems like flow velocity, density, temperature, and chemical concentrations for any area where flow is present. Today it's a numerical method applied in various industries by combining computational tools and the theory of fluid dynamics in order to achieve flawless product designing. The reduction of local scour downstream of bridge piers got a considerable attention by numerous studies. The purpose of this study was to calculate and quantify the influence of hydraulic structural measures on reducing the scour around a group of bridge piers. In the simulation, the downstream semicircle diameter was fixed by a 10 cm, while the upstream diameter was changed to 4 and 10 cm. Discharges with Q=0.057 m3/s and 0.038 m3/s the piers were tested under clear-water conditions for the duration of 6 hours. Then the results have been compared with laboratory measurements. The agreement between calculated scour depths and laboratory measurements is found reasonable. Keywords: Local scour, scour reduction, bridge pier, group bridge pier.
Atıksu arıtma tesislerinde risk değerlendirmesi
Bu çalışmanın amacı evsel nitelikli atıksu arıtma tesislerindeki oluşabilecek iş kazalarını ve meslek hastalıklarını belirlemek ve oluşabilecek iş kazası ve meslek hastalıklarını ortadan kaldırabilmektir. Çalışma sırasında Mersin ilinin Anamur, Bozyazı ve Mut ilçelerinde bulunan farklı teknoloji ve proseslerden oluşan arıtma tesislerinden yararlanılmıştır. Aktif olarak görev aldığım 3 tesiste 9 aylık izleme sonucu gözlemlenen ve ortadan kaldırılan risk faktörleri incelenmiştir. Bu incelemeler sonucunda 3 tesiste de belirlenen bölümlerde 3T yöntemi kullanılarak risk değerlendirmesi yapılmıştır. Değerlendirme öncesi ve sonrasında elektriksel ve biyolojik risklerin daha az olduğu görülmüştür. Tesislerde incelenen bölüm ve ekipmanlar da büyük risklerin sırasıyla geri devir ünitesi, çamur susuzlaştırma ünitesi, giriş terfi ünitesi, havalandırma havuzları, çökeltme havuzları, laboratuvarlar, atölyeler, blower binası, kum ve yağ tutucu ünitesi, kaba ızgara, ince ızgara ve idari binalardır. Sonuç olarak incelemeler dahilinde riskler belirlenerek ve önlemler alınarak iş kazaları ve ölümler ortadan kaldırılmaya çalışılmıştır.
Investigation of local scour around group bridge pier with different shapes
This study is based on laboratory experiments for computing depth of local scour around group bridge pier, considering the effects of upstream flow conditions, size of pier, median size of bed material and spacing between bridge piers on the maximum scour depth and scour pattern around bridge piers. The study was conducted using a physical hydraulic model for bridge piers, operated under clear-water condition and using uniform cohesionless sand as bed material. Three different models of bridge piers, having different sizes were used for showing the effect of the size on the local scour. The diameter of upstream bridge piers (D1) was varied to 2, 4, 6, 8, and 10 cm, and diameter of downstream bridge piers (D2) 10 cm for all. The spacing (S) between the bridge piers was varied three times 20, 30, and 50 cm for all groups. This experimental study was conducted in order to assess the reduction of local scour around group of bridge piers. The results of comparison between the performances of group of bridge piers under different span lengths reveal that the scour depth increases with increasing span length. We hope that the results of the present study will benefit the designers and engineers.
Simulation of blockage effects on scouring downstream of box culverts under unsteady flow conditions
Scouring at the downstream of culvert considered as one of the main reasons of culvert failure. Failure of the culvert structure is a catastrophic phenomenon. Studying the causes of scouring will give an idea about the solution probabilities; the blockage and geometry of culvert have a great influence on the local scour. In this study, simulated results that obtained from Flow-3D software of box culvert model and formation of scour at the outlet are compared with laboratory results of (Sorourian, 2015) to evaluate the accuracy of the numerical model. Laboratory box culvert was carried out for two conditions; the non-blocked situation and the partially blocked condition with the blockage ratio of 40%, for this destination used two different sizes of plates and the finer sediment was used in Sayana's study with the median grain size being 0.85 mm and 2.0 mm, the flow conditions in the laboratory were unsteady. It is mean that the flow rates during the time were changed. The performance of the numerical model based on renormalization group (RNG) and k-ε model compared with experimental results. The comparison shows that the RNG results has a good agreement than the k-ε model