scholarly journals Soil resistance in the process of dams’ irrigation canals profiling

2020 ◽  
Vol 175 ◽  
pp. 09005 ◽  
Author(s):  
Alexander Apalkov ◽  
Sergey Apalkov ◽  
Sergey Kuren ◽  
Sergey Popov ◽  
Nikolai Dontsov

The questions of processing technology of dam channels using appropriate mechanisms are presented taking into account the requirements of modern engineering hydrology. Channel profiling with the best quality and performance can be carried out by means of mechanization at the expense of working tools, able to process not only longitudinal but also cross-sections of channels. According to calculations, there was established, that the best condition for moving soil on the channel slope in front of the passive knife, is an equable distribution along the slope. It was marked, that the strength of the soil pressure is most affected by the installation value of the trowel knife and the thickness of the loosened soil layer to be compacted. Recommendations on increasing the active working body stability of the dam profiler are given.

Author(s):  
Charles J. Oswald

Measurements made on a long span reinforced concrete arch culvert under 7.3 m (24 ft) of silty clay backfill were compared with results from finite-element analyses of the soil-structure system using the CANDE finite-element code. The culvert strains and deflections and the soil pressure on the culvert were measured during construction and during the following 2.5 years at three instrumented cross sections. The CANDE program was modified to account for the effects of concrete creep and shrinkage strains after it was noted that the measured postconstruction culvert deflection and strains increased significantly whereas the measured soil pressure on the culvert remained relatively constant. Good agreement was generally obtained between measured and calculated values of the culvert strain and deflection and the soil pressure during the entire monitoring period after the code was modified.


2020 ◽  
Vol 3 (3) ◽  
pp. 865
Author(s):  
Markus Jusuf ◽  
Aksan Kawanda

ABSTRACTIndonesia is a country located in the most active earthquake paths in the world. This makes Indonesia prone to earthquakes and has the potential to experience liquefaction. Liquefaction can cause pile failure, so several things need to be considered in designing piles on potentially liquefied soils. One project in Sulawesi has a profile of uniform grained saturated soil that is susceptible to liquefaction. Two things that need to be considered in the design of piles on potentially liquefied soils is to ignore the capacity of pile friction and calculate the moment due to lateral spreading effects. Calculation of liquefaction potential is done by comparing the ratio of the cyclic stress and the cyclic resistance ratio and is compared by four other methods namely: the Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), and Bray & Sancio (2004). The lateral spreading effect is calculated by referring to the JRA Code where the liquefied soil layer gives pressure to the pile at 30% of the overburden stress and the soil layer above the liquefied soil gives passive soil pressure to the pole. The moment effect caused by lateral spreading results in the addition of dimensions or number of poles.Keywords: liquefaction; lateral spreading; bearing capacity; JRA Code; pile foundationABSTRAKIndonesia adalah negara yang terletak di jalur gempa teraktif di dunia. Hal ini menyebabkan Indonesia rawan gempa dan memiliki potensi untuk mengalami likuifaksi. Likuifaksi dapat menyebabkan kerusakan/kegagalan struktur yang sangat merugikan, sehingga perlu diperhatikan beberapa hal dalam merancang tiang pada tanah berpotensi likuifaksi. Salah satu proyek di Sulawesi memiliki profil tanah pasir berbutir seragam dan jenuh air yang memiliki potensi likuifaksi. Dua hal yang perlu diperhitungkan dalam perancangan tiang pada tanah berpotensi likuifaksi adalah mengabaikan daya dukung friksi tiang dan memperhitungkan momen akibat efek lateral spreading. Perhitungan potensi likuifaksi dilakukan dengan membandingkan rasio tegangan siklik (CSR) dan rasio hambatan siklik (CRR) serta dibandingkan dengan empat metode lainnya yaitu: metode Seed et al. (2003), Tsuchida (1970), Seed et al. (2003), dan Bray & Sancio (2004). Daya dukung aksial pada tiang pancang mengalami pengurangan 32% akibat lapisan tanah yang terlikuifaksi. Efek lateral spreading dihitung dengan acuan JRA Code dimana lapisan tanah terlikuifaksi memberikan tekanan ke tiang sebesar 30% dari tegangan overburden dan lapisan tanah di atas tanah terlikuifaksi memberikan tekanan tanah pasif ke tiang. Efek momen yang diakibatkan oleh lateral spreading mengakibatkan penambahan dimensi ataupun jumlah tiang.Kata kunci: likuifaksi; lateral spreading; daya dukung; JRA Code; fondasi tiang    


Author(s):  
Jonathan C. Corbett ◽  
Navid Goudarzi ◽  
Mohammadamin Sheikhshahrokhdehkordi

Abstract This research explores utilizing distributed wind turbines in the built environment computationally. The targeted wind turbine design is an unconventional ducted turbine, called Wind Tower technology that its operation and performance metrics have been studied in earlier works in the team. Wind Tower is an established architectural technology that operates by catching wind and directing it into buildings, providing natural ventilation to support HVAC systems, and thus reducing cooling costs in urban environments. Wind power has long struggled to meet expectations in built (urban) environments. By combining wind towers at different cross sections with wind turbines, one might develop a device which provides natural ventilation and produces power in spite of a hostile wind environment. The preliminary results suggest that the maximum potential for a wind tower-turbine combination appears to be 700-1.46 kW under idealized conditions with a 4 m/s site dominant wind speed. This suggests that wind towers might be viable for power harvesting in both remote and grid connected regions. Further analysis suggested that additional turbine performance enhancements are needed to bring the turbine real power production closer to that ideal.


2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Bin Wang ◽  
Wenzhe Cai ◽  
Qingxuan Shi

Sectional deformation quantities, such as curvature and ductility, are of prime significance in the displacement-based seismic design and performance evaluation of structural members. However, few studies on the estimates of curvatures at different limit states have been performed on asymmetric flanged walls. In this paper, a parametric study was performed for a series of T-shaped wall cross-sections based on moment-curvature analyses. By investigating the effects of the axial load ratio, reinforcement content, material properties, and geometric parameters on curvatures at the yield and ultimate limit state, we interpret the variation in curvature with different influencing factors in detail according to the changes of the neutral axis depth. Based on the regression analyses of the numerical results of 4941 T-shaped cross-sections, simple expressions to estimate the yield curvature and ultimate curvature for asymmetric flanged walls are developed, and simplified estimates of the ductility capacity including curvature ductility and displacement ductility are further deduced. By comparing with the experimental results, we verify the accuracy of the proposed formulas. Such simple expressions will be valuable for the determination of the displacement response of asymmetric flanged reinforced concrete walls.


2011 ◽  
Vol 58-60 ◽  
pp. 2570-2575
Author(s):  
Wen Bang Sun ◽  
He Xin Chen ◽  
Wen Bing Sun ◽  
Mai Yu Zhou

With the development of information processing technology, 2-D DCT has been used more and more widely. But the 2-D DCT is accomplished by computing twice 1-D DCT successively, and cannot embody the total space characteristic of 2-D transform well. To overcome such drawbacks, the paper has broken the traditional thinking of DCT operation, and proposed 2-D SDCT operation method. First, some new 2-D matrix operation principles are defined. Then, the transform basic matrix used for 2-D SDCT operation was build and the operation principle of 2-D SDCT is described in detail. Finally, the performance of 2-D SDCT was described systematically. The theoretical analysis shows that the proposed method makes 2-D DCT succinct to express, easy to comprehend and convenient to operate.


2012 ◽  
Vol 549 ◽  
pp. 737-740
Author(s):  
Jiang Zhu ◽  
Guo Zhong Li

FGD gypsum, fly ash and wheat straw are taken as main raw materials; waterproof agent, water reducer, activator and composite retarder are chosen as admixtures, and wheat straw reinforced desulfurization gypsum block is produced through reasonable processing technology. Block ratios of material, processing technology and performance are analyzed.


2016 ◽  
Vol 83 (12) ◽  
Author(s):  
Simon Graner ◽  
Denis F. Hinz ◽  
Christian Breitsamter

AbstractWe study characteristic flow patterns downstream of a standardized swirl disturbance generator using laser-Doppler velocimetry (LDV). To investigate the spatial development of flow patterns, we conduct LDV measurements in cross-sections located at various distances downstream from the swirl disturbance generator. Focusing on velocity profiles, decay of swirl, and performance indicators used to describe the characteristic shape of the velocity profiles, we systematically compare the experimental results with available references and various theories for decay of swirl disturbances. We find that the standardized swirl disturbance generator provides exponentially decaying swirling flow that is best captured by the theory of Steenbergen and Voskamp


Author(s):  
W. John Dartnall ◽  
John A. Reizes

Engineering Thermodynamics is that engineering science in which students learn to analyze dynamic systems involving energy transformations, particularly where some of the energy is in the form of heat. It is well known that people have difficulty in understanding many of the concepts of thermodynamics; in particular, entropy and its consequences. However, even more widely known concepts such as energy and temperature are not simply defined or explained. Why is this lack of understanding and clarity of definition prevalent in this subject? Older engineering thermodynamics textbooks (often containing the words “heat engines” in the title) had a strong emphasis in their early chapters on the general physical details of thermodynamic equipment such as internal and external combustion engines, gas compressors and refrigeration systems. The working fluid in these systems might expand or contract while heat, work and mass might cross the system boundary. The molecular workings within the thermodynamic fluid are not of prime concern to the engineer even though they are to a physicist or chemist. Modern engineering thermodynamics textbooks place great emphasis on mathematical systems designed to analyze the behavior and performance of thermodynamic devices and systems, yet they rarely show, at least early in their presentation, graphical images of the equipment; moreover, they tend to give only passing reference to the molecular behavior of the thermodynamic fluid. This paper presents some teaching strategies for placing a greater emphasis on the physical realities of the equipment in conjunction with the molecular structure of the working fluid in order to facilitate a deeper understanding of thermodynamic performance limitations of equipment.


2008 ◽  
Vol 400-402 ◽  
pp. 269-274 ◽  
Author(s):  
Naveed Anwar ◽  
Mohammad Qaasim

Several parameters and corresponding performance of reinforced concrete column cross-sections of different shapes (square, rectangular, circular, T-shape, I-shape, cross-shape, L-shape and C-shape) under various loading conditions have been studied in order to determine the suitable and optimum cross-sections for strength and ductility. In each cross-section shape, parameters include compressive strength of concrete (f’c), tensile strength of steel (fy), steel ratio (As/Ag), and angle of bending. In order to demonstrate the behavior and performance of the sections in terms of strength and ductility, CSISectionBuilder software was used to define the stress-strain curve for concrete and steel and then compute the moment-curvature relationship for each section. Considering different sections, the number of parameters in every section and various loading conditions, a total of around 1,800 sections were analyzed. The comparison procedures started within each section shape, and then across different sections in order to determine the most suitable cross-section for strength and ductility. Results of the study are deemed very useful in the system selection and preliminary design of important structures such as buildings with complicated geometry and high architectural demand including bridge piers and hydraulic structures.


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