نشریه مهندسی عمران فردوسی
سال سی و سوم شماره 4 (زمستان 1399)

Accurate measurement of flow discharge in open channel and water and sewage transmission networks it is of special importance. So far, various types of structures, such as overflows, stomata, flumes and sliding valves, have been proposed for measuring current flow. The proportional weirs are a group of sharp edges weirs that are highly accurate due to low sensitivity to upstream depth variations. In linear proportional weirs, there is a linear relationship between the head and the discharge. In this study, based on theoretical fundamentals of proportional weirs, three proportional linear weirs with linear, triangular and reverse triangular, and two reverse triangles and three series of rectangular weirs were designed and tested in rectangular flume equipped with a side channel in hydraulic lab. About 400 laboratory experiments were carried out lead to, establish a linear relationship between the head and the discharge in linear proportional weirs based on the measurements. The range of the studied discharges varied from 2 to 16 liters per second. The experiments showed that the coefficient of discharge is as a function of two ratios, which are the water depth at the top of the weir and the length of the crest to the height of the weir. Based on these ratios, for each weir a relationship for the discharge coefficient was determined. The average error for proposed equation for linear correlation weirs was equal to 1.5 percent and for over 90 percent of laboratory data the average errors were less than this value. The results show that theoretical sensitivity in linear proportional weirs is equals to one, the more the values of the sensitivity of the studied weir are close to the theoretical values, the better the weir will be. In order to estimate the laboratory sensitivity of the above weirs, the derived relationship between the discharge and head of each weirs was used and compared. The results showed that among linear proportional weirs, inverse triangular weir with a linear relationship, has better and more accurate hydraulic performance.

Recently, there has been an increasing trend toward the use of sustainable materials. Sustainability helps the environment by reducing the consumption of non-renewable natural resources. Concrete – the second most consumed material in the world after water – uses a significant amount of non-renewable resources. Efforts aimed at producing environmentally friendly concrete can play a major role in securing sustainable construction.Candidate technologies for sustainable concrete materials include the incorporation of supplementary cementitious materials (SCMs) as a partial replacement for Portland cement; as well as recycled materials in concrete production. As a result, an experimental investigation was conducted to study the mechanical properties and durability of concrete constructed with 15% and 30% recycled aggregate concrete as well as 10% zeolite. This experimental program consisted of fourteen mix designs. Thecompressive strength,split tensile strength, electrical resistivity and chloride ion penetration of recycled concrete mixes were compared with the conventional concrete. Results of this study show that the zeolite and recycled aggregate concrete increased compressive strength,split tensile strength and electrical resistivity also decreased chloride ion penetration of concrete. To overcome inferior durability andmechanical properties of recycled mixes, zeolite (10%) has been added to recycled mixes. Results of the mixes including both recycled aggregate concrete and zeolite show superior durability (both electrical resistivity and chloride ion penetration) compared with the conventional concrete.

Installation of stone particles is a very common method to protect abutment against scour. An alternative is concrete elements. In this research, installation of pebbles, Six-Legged Concrete (SLC) elements and combination of them is studied in laboratory. SLC elements were installed in open and dense arrangements with three different depths; on the bed, under the bed and the median case around wing-wall and vertical-wall abutment. Generally, results showed the significant effect of scour mitigation when both methods were applied so that, the maximum scour depth at the abutment toed was reduced up to 70% in vertical wall abutment and totally eliminated at the wing wall abutment. Edge failure was observed when the best scour reduction was achieved in SLC elements installation case. However, best countermeasure was achieved when both methods were applied while edge failure was also controlled. Transformation of the maximum scour depth from the abutment toe to the channel midway at the downstream of the abutment is also discussed.

Speeding has been recognized as a common violation particularly among the younger drivers. Drivers' attitudes and beliefs are among the factors influencing drivers’ speed selection. The present study investigates the role of young drivers' attitudes and beliefs on the deterrence of speeding penalties including “monetary fines”, “demerit point”, “car impoundment”, and “social deprivation”. We designed a stated preference survey to investigate the drivers’ choice of speeding penalties. The convenience sampling method was used to collect data (n=550) at campuses of Kharazmi University in Karaj, College of Engineering at the University of Tehran, and the East Tehran Branch of Islamic Azad University. We conducted a Multinomial Logit (MNL) regression to correlate the drivers’ selection of the speeding penalties to attitudes towards excessive speed and road crashes, as well as their beliefs about speed penalties. According to the results, for drivers who had a positive attitude toward accidents, social deprivation was more deterrent than demerit points and monetary fines. Moreover, analysis of the interaction between drivers' beliefs about traffic penalties and social deprivation showed that compared to other drivers, for drivers who did not have a positive belief about traffic penalties, the mechanism of social deprivation was less deterrent. The implications of these findings have been discussed.

According to Articles 155 and 168 of the Fifth Development Plan Law, any construction must be carried out with standard materials and its application by competent builders, and each building must be insured for ten years. Accordingly, the main purpose of this study is to investigate the barriers and problems affecting the standardization of construction materials in Lorestan province. The research method in this research was quantitative-qualitative (mixed) of exploratory type. In this method, the research team first developed a questionnaire including open-ended questions according to the objectives and questions of the research. After compiling the questionnaire and selecting the panel members, the interviews began. At this stage, fifty managers of material production centers, employers, experts of the provincial engineering organization, urban housing, standard administration, executives, and supervisors of construction projects were coordinated and interviews were conducted. The sample size was so saturated that the interviews in this section were saturated with fifty people and in the quantitative section it was a random sampling method in which three hundred and twenty-five manufacturers, consumers, supervising engineers, laboratory testers using Cochran's formula. Colleagues and contractors were examined. To collect information in this study, in-depth interviews, questionnaires, field observations, and experiments (obtaining the results of forty samples of tests performed by accredited laboratories by the General Directorate of Standards in the province and analyzing these tests based on existing standards) have been used.

In the present century, the use of various petroleum products and fossil fuels has been an integral part of industry and human progress. Nowadays the major concern, in addition to the use of petroleum products, is their uncontrolled diffusion in various parts such as extraction, processing, transfer and use. The other problem with the utilization of these products has arisen in the field of geotechnical engineering includes environmental pollution and the creation of problematic contaminated soils. Many solutions to these problems have been investigated and presented separately. In the present study, the microbiologically induced calcium carbonate precipitation (MICP) method, as a solution to purify contaminated soils and to improve its reduced bearing capacity with two petroleum products, diesel and engine oil, has been proposed. The bacterium used in this process was Sporsarcina pasteuri, which was added to the contaminated soil as a flocculate bacterium. In two stages; purification evaluation (using chromatographic results) and geotechnical improvement (using direct shear and permeability test results) were performed. With the aid of FTIR (Fourier-transform infrared spectroscopy) analysis and chromatographic diagrams, a reduction of peaks of the identified components in the treated sample in comparison to the standard sample (prepared from diesel or engine oil) was observed. On the other hand, improving the geotechnical properties of contaminated soils was one of the most important effects observed in the treated samples.