روزبه آقامجیدی

In recent years, the issue of providing drinking water and ensuring public health for the residents of the city of Mashhad has emerged as a top priority for the authorities in charge. As part of addressing this concern, a proposed solution involves the transfer of water from Chehchehe and Qaretikan dams through the construction of water catchment structures downstream of these dams. The water would then be channeled to the water transfer tunnel of Dosti Dam for eventual delivery to the city of Mashhad.

In this study, an evaluation was conducted on the alterations in water allocation stemming from the presence of two dams over a 24-year span from 1997 to 2020. Factors such as potable water requirements, agricultural demands, ecological considerations, and the water agreement between Iran and Turkmenistan were taken into account using WEAP model. Subsequently, the second phase of the study involved an assessment of the fulfillment of the aforementioned needs, utilizing the percentage of meeting index.

Based on the findings, it is evident that the transfer of water within the allowable volume limit is both feasible and viable. It is imperative to emphasize that maintaining current loading levels, without any additional burden, is crucial for sustaining a reliable water supply for the city of Mashhad via the two dams.

The Use Of Color Spectrums In The Urban Space Can Be Seen In The Facades Of Buildings, Flooring, Urban Furniture, Sidewalks And Streets. The Use Of Colored Concrete For Facade Construction And Decoration Design Can Be Welcomed For Many Reasons. Also, This Method Does Not Require The Use Of Other Materials To Cover The Work, In Which Case The Costs Of Facade Work Will Be Significantly Reduced. But Temperature Changes And The Cycle Of Melting And Freezing In Unstable Environmental Conditions Is One Of The Factors Of Concrete Failure. Therefore, In Addition To Beauty, Colored Concrete Must Be Resistant To Different Environmental And Atmospheric Conditions. Yellow Is One Of The Three Main Colors In The Color Wheel. In Architecture, Yellow Is A Practical Color And It Makes Spaces Appear Bright And Large Due To The Large Amount Of Light It Reflects. The Pigment Of Mung Bean Or Limonite Is A Type Of Mineral Soil That Has A Large Amount Of Iron Oxide. This Pigment Is Found In Dull Yellow Or Mustard Colors. In This Research, To Change The Color Of Concrete To Yellow, White Cement And Limonite Pigment Were Used In Different Weight Ratios Of 5%, 10%, 15% And 20% In Concrete. Further, To Check The Behavior And Durability Of Concrete, Compressive Strength Tests, Water Absorption In Hardened Concrete, And Durability Of Melting And Freezing Were Investigated. The Results Of This Research Showed That The Colorability Of 5% And 10% Limonite In Concrete Will Cause Pea And Cream Color And The Use Of 15% And 20% Will Cause Yellow Color. Also, The Use Of 10% Limonite In Concrete Increased The 28-Day Compressive Strength By 8%. But Due To The High Water Absorption Of Limonite, Its Freezing Durability Decreased Compared To The Control Sample.

Basically, heavy concrete has the specific weight of about 1.5 to 2.5 times of the normal concrete. Materials with high specific weight are employed as a part of used aggregate to make heavy concrete. Heavy concrete is utilized as a protective shield against radiation. Heavy concrete is applied in the structure of nuclear infrastructures or hospitals. Ilmenite is a type of mineral that is also considered as mineral waste. Ilmenite is extracted directly from titanium mine and is found plentifully in Iran. In this study, Ilmenite is used in different volume ratios of 10%, 20%, 30%, and 40% instead of sand to make heavy concrete. Moreover, nano-silica gel, is used at the rate of 1% by weight of cement, to increase the quality and durability of concrete against the cycle of melting and freezing. The tests performed in this research include compressive strength test, tensile strength test, defining the primary and secondary water absorption rate and determination of concrete melting and freezing durability, according to ASTM-C666 standard. Results depicted that, the specific weight of heavy concrete would meet the regulations, by adding at least 20% of ilmenite instead of sand in concrete mixture. Also, adding 30% by volume of ilmenite, instead of sand, will increase the final compressive strength (90 days) by 33%. Finally, applying nano-silica gel in the heavy concrete mixture, makes the concrete stable against the melting and freezing cycles.

Compared to regular columns, short columns absorb more earthquake force due to their greater stiffness. For this reason, short columns are seriously damaged during an earthquake and sometimes cause the destruction of the entire structure. When short columns are displaced as much as long columns, shear and joint failure occurs in them due to the absorption of more energy. In this research, by using the laboratory results of a short column subjected to lateral reciprocating loads, an attempt was made to select the most optimal state with the help of steel sheets covered with different shape patterns. For this purpose, to determine the effect of retrofitting on the short column, six different installation modes of the proposed steel cover were used in abaqus software for finite element analysis. Next, the studied short column was subjected to reciprocating cyclic loading according to the standard pattern. The results of this research show that retrofitting a short column with an integrated steel sheet is able to increase the seismic resistance of the column by 49%, but the most optimal retrofitting method in terms of strength and volume of steel used is the retrofitting method with model-2 installation pattern.

Affected by numerous elements, the estimation of manning's roughness coefficient is of great importance and sensitivity. In the present study a reach of 56 km from beshar river in kohgiluyeh and boyer-ahmad province was studied. The selected reach was divided into 12 sub-reaches based on similar characteristics. Experimental and quasi-experimental methods, tables, and cowan's method were used to estimate manning's coefficient. The estimation results were compared with stage-discharge rating curves from two hydrometric stations located in the selected reach. The ‘inverse solution’ was proved to be the best method to estimate manning's coefficient in the river under study followed by bruschin and cowan's method with an average error of 0.237 and 0.241, respectively.

The phenomenon of flood, in spite of all its complexities, can be studied and appropriate solutions can be sought to control and reduce its damage and even economic exploitation of floods. On the other hand, before constructing any hydraulic structure such as dams, overflows, diversion channels, temporary dams, etc., it is necessary to have the information of maximum possible flood and flood hydrograph with different return periods in order to estimate the magnitude of different floods and predicted the maximum height of the river flood zone, the maximum area and width of the river flood in different areas, the maximum flow velocity, changes in shear stress, flood volume, changes in landing number and hydraulic radius, etc. flood routing and zoning operations or quantifying river confluence for flood alert systems. in this study, by selecting the case of Sivand river in fars province in the specified time period, flood frequency analysis was performed with the help of Smada and Easyfitt software and the maximum flood discharge was determined with different return periods. then, by selecting tangbolaghi hydrometric station as the representative station of Sivand river, hydraulic flood routing and zoning operations were attempted by Mike11 computer model.

Overflows are generally installed to drain excess water or floods that the volume of the tank can not store. In diversion dams, overflow is used to bypass or divert current in excess of system capacity. Demolition of many dams occurs due to incorrect design or insufficient overflow capacity. Proper spill design is more important in gravel earthen dams than in concrete dams. because the probability of destruction of earthen and gravel dams due to water passage is much higher than concrete dams. In the present study, a comprehensive review of the types of applied overflows based on effective dynamic and kinematic parameters was performed. Also, definitions and summaries of different types of free overflows were shot, siphon, stepped, congressional, lateral, tunnel, circular crown, peak, lotus or tulip. Then, the mechanism of vortex formation was introduced and an overflow appropriate to this phenomenon was introduced. The results of these cases showed that the application of lotus or tulip overflow in flood areas with high discharge has better performance.

In general, Spillway are divided into two types linear and non-linear, among which, the Morning Glory overflow is a non-linear overflow. In some cases, the hydraulic performance of the overflow is affected by the immersion coefficient and its hydraulic efficiency is reduced and affected by the immersion. Structures such as vortex breakers (separators of flow lines to increase transit efficiency) and to increase overflow efficiency should be used. In this regard, using dimensional analysis by Buckingham method, it was determined that the overflow coefficient of the overflow is a function of variables such as vortex breaker height ratio (Hvb / Rs), vortex breaker thickness ratio (Tvb / Rs), number of vortex breakers (VB) and overflow shape factor ( Sf) is. The experiments of the present study were performed on a square flume with dimensions of 2.5 × 2.5 and a height of 2 m 0.20 1 1.05 /0 1.05 m3. The results showed that the overflow of stepped Morning Glory (12 steps) and vortex breaker with high height and 6-array arrangement has a much better and more suitable performance compared to non-stepped overflow and has increased the permeability coefficient by 23%.

Increasing study and research on the components of concrete structures has led to the availability of materials, the use of which in turn has been able to have a tremendous impact on concrete production. Concrete is undoubtedly the most important building material, the production and consumption of which is increasing day by day and it is used in almost all structures. The performance of cement as one of the main components of concrete products has always been considered and with the increasing development of Iran's cement industry in terms of quantity in the production of cement, cement quality control by examining physical and chemical properties is very important. In this study, we tried to investigate the factors affecting the strength of hydrated cement used in concrete structures in Shiraz and the results indicate a decrease in concrete strength due to increasing the ratio of water to cement and also C3S and C2S are the two main compounds causing cement strength are hydrated.

One of the main factors in the collapse of the bridge piers in rivers is local scouring. By placing the piers in the direction of the streams, a complex three-dimensional flow is formed around the pier that has been the popular subject of research by many researchers. Methods of reducing the depth of local scouring are divided into two systems: 1. increasing the strength of bed materials around the piers by using more resistant materials, such as riprap, collar and gabion in the riverbed. 2. Reducing the strength of the main factors such as downward flow and horseshoe vortex by the deflector, blade and submerged Vane or changing the geometric shape. In the present study, the effect of the deflector shapes such as triangles and curved surface on the maximum scour depth around the pier under clear water conditions were investigated. General factors of bridge pier scour include down-flows, horseshoe vortex, and wake vortex. In general, the flow impact on the pier and its separation is the main factors that form scour holes around piers.

The experiments were done in the laboratory of Khuzestan water and power authority laboratory (KWPA), equipped with a flume with a length of 10 meters and a height of 500 mm and a width of 310 mm. The flume is equipped with an electromagnetic flow-meter with an accuracy of ±0.1 liters per second and a weir downstream of the flume to adjust the water level. In this study, natural river sand with uniform grain size (δg = 1.36), relative density Gs = 2.64 and the average particle diameter of 0.95 mm. In all experiments, water depth was considered 100 mm. In this research, three different models of PVC deflector surface (the deflector surface shapes such as triangles, curved and simple surface) with angle's face (θ= 15, 30 and 45-degrees). It should be noted that the angle of flow with the deflector head is calculated as α = 90-θ, which used to describe and analyze. The unprotected pier scouring investigated to represent a basis for controlling and comparing with the other scour and bed change conditions. A 12-hour control experiment was also conducted on the control pier to determine the experiment time (equilibrium time), and scour depth changes were recorded in the time unit during experiments.

The horseshoe vortex around the scour hole accelerates digging and transfers the sediments separated from the bed downstream with the main flow. The flow's separation from around the pier also creates perpendicular vortexes on the sedimentary bed known as wake vortexes. These vortexes are active behind the pier, separate the bed particles like a tornado, expose them to the flow, and help move sedimentary particles from the front and sides of piers downstream. The scour hole digging by the horseshoe vortex continues until the water volume inside the scour hole increases and exhausts the vortex energy. In this state, the scour depth changes negligibly over time and reaches equilibrium, and Figure 1 show the scour mechanism. In this study, to reduce the scouring depth pattern around the pier, three shapes of the deflector (the deflector surface shapes such as triangles, curved and simple) with three angles were used. The results showed that by reducing the head slope from 40 to 15 degrees, scouring depth decreases. For all deflectors with 15 degrees in the parameter (U/Uc=0.70), the percentage of the scouring depth reduction is close to 83 to 89 per cent. In the parameter U / Uc=0.96 near inception motion that is the most critical state and the value most comparable to the particle incipient motion, the deflector with triangle surface shows a decrease of 85%, curved surface 77%, and simple 75%. By reducing the angle of the deflector, part of the flow lines didn't deviate towards the bed, which reduced the potential of the high-pressure zone created at the pier. This reduction in compressive potential reduced the flow velocity of the back vortices and, ultimately, reduces their ability to transport sediment downstream. Based on the results, the deflector with a triangle surface shape in all flow conditions had a better and lower scour hole depth than the carved and simple shape.

This study used a deflector structure to reduce and control the scour depth around bridge piers. The flow effect was investigated by implementing these protections and their impact in various relative velocities (U/U_c=0.97,0.83,0.70). The scouring pattern and sediment point bar created around the pier with The deflectors protection compared with the control pier (without protection) have less scouring depth due to minor deviation of flow streamlines and reduced disturbances around the pier. Finally, the deflector with a triangle surface shape has a better response to reduce the scouring hole. The results state that the deflector at the 15-degree angle significantly affects the flow deflection near the bed, corrects the flow pattern around the pier, and reduces scouring depth.

Unsteady currents in pipes can occur in various forms, one of which is the unsteady current of damping, which is called Surge shock.These currents are in the form of pressure waves and if not controlled in some way, can cause irreparable damage to the pipeline. In the present study, the ram phenomenon was introduced and the effects of different parameters, pipe thickness and diameter, different flow velocities on the dynamic loads due to the occurrence of ram impact were investigated.Finally, it was observed that under the same conditions, the effect of pipe material is 25% effective in reducing the maximum impact. The maximum impact increase is about 1% due to a very small increase in pipe thickness. Doubling the moment of inertia reduces the maximum impact pressure by about 42%, which has been investigated using Water Hammer software.

Spillways are designed in different methods according to the operating conditions, type of structure, site conditions of the dam, and hydraulic characteristics. One of them is the Glory spillway, which consists of a circular opening, a vertical circular opening, and a horizontal pressurized tunnel. The present study investigates the effect of stairs and their numbers as well as the effect of the presence of a vortex breaker on the hydraulic performance of the Glory spillway. This is due to the simplification of the geometric shape during construction and increasing the efficiency of the flow. Based on the results, it was observed with the coefficients of low immersion ratio,4 floors have the highest performance in discharge transfer. Also, increasing the immersion ratio coefficient of stairs will reduce the hydraulic performance of the spillway. On the other hand, in all cases (except in the case of spillway with 12 floors), the presence of a vortex breaker with a triple arrangement can affect the separation of vortex breakers, which ameliorates the flow transfer efficiency from the spillway and separation of flow lines.

Flexural reinforcement of reinforced concrete beams with composite materials is one of the most common methods of structural reinforcement. Composite materials have several advantages such as ease of implementation, easy access, relatively low cost, increased bearing capacity, low weight, etc., but despite all these advantages, the use of these materials also has disadvantages, which can be Premature and sudden bending failure in beams reinforced with these materials, which occurs due to premature rupture of composite materials or even deterioration of the joint area due to lack of attention to the stability of epoxy adhesive from the concrete surface in the tensile zone of the beam, noted. In this paper, by designing a computational program with Abacus software, 7 examples of reinforced concrete beam reinforcement design with GFRP rebar by near-surface installation method (NSM) and its integration with various FRP sheet enclosure cases taken from a This is a laboratory study, an attempt was made to prevent premature failure of the reinforced beam and to be able to use the maximum capacity of GFRP rebar. It is noteworthy that in modeling this reinforcement design with composite materials, the effect of ultimate adhesion resistance and failure or deterioration of epoxy adhesive between NSM rebar and concrete surface is important, so in this modeling of the joint area which is epoxy adhesive modeling and its behavior Has been examined. The use of this reinforcement method with four NSM rebars and FRP sheets increased the final bearing capacity by more than 60% compared to conventional reinforced concrete beams.

Local scouring around the bridge pier is the leading causes of their destruction. Thus, to reduce and control this phenomenon, numerous researches have been done and many solutions have been suggested. These solutions are classified in two parts, direct and indirect protections methods. In this study, by definition different scenarios, both protection methods and their combined effects were investigated. In this research, cable around piers, as an indirect method, and sill as a direct method were used. Different locations of the sill (front and back of the pier) and the cable around the pier with relative pitch equal to 0.33, 0.50 and 0.67 in clean water conditions were investigated. In the best case, the pier with a front sill and a relative cable pitch of 0.33, has the least amount of scouring. This pier has the highest amount of scour depth reduction with 63% among the other scenarios. In this regard, the pier with a back sill and a relative cable pitch of 0.33, showed 45% reduction in scouring. This indicates that under the same conditions, with the sill movement from the back to the front of the pier, scouring depth parameter improved 18 percent.

the sediment accumulation in the reservoirs places upstream and downstream of the dam under the influence of ecosystem changes. In order to increase the volume of regulated water in the river basin and prevent the introduction of river sediments into the dam reservoir and as a result of increasing the useful life of the dam and the optimal management of water resources in the given time, the required data from the relevant companies from the Tangab Dam was obtained and Using Karun's analysis software, based on the calculations performed by the software, the modified volume (after sedimentation) after one year and after 50 years from the beginning of operation, using the method of increasing the level to The order of 1021.646 million cubic meters and 605.664 million cubic meters, and also for the method of reducing the level of these numbers is equal to 1021.6 million million Rmkb and 064/580million cubic meters is estimated. Given the reservoir type and sediment volume, the curves of hp and h'p are plotted. According to the power plant's level, the reservoir level of the dam increases with the calculation of sediment distribution by increasing the level after 110 years from the plant's level of utilization, and this also occurs in the method of reducing the level after 100 years.

Hydraulic structures such as stilling basins, mainly are used for the purpose of energy dissipation in the lower zone of overflows, chute and diversion dams, in order to control hydraulic jump. In this research, the rate and effect of the jump is determined by laboratory tests. In these experiments, the sharp roughness of the bed of basin and also the change in the slope of the basin( structure ) from 0 to 0.3 percent were tested and parameters such as flow rate, initial depth, secondary depth, jump length of water surface profile, water head on overflow crown and water head prior to overflow were accurately measured. The analysis of data showed that the sharp roughness can effectively reduce the length of jump to to 35.5%. For sharp shape roughness, with an increase in the landing rate, the ratio y2 / y1 increases by an average of 6.5%. For a Froude number with a sharp roughness setting, the Lj / y2 ratio decreases by an average of 1.2%.