نشریه عمران و پروژه
پیاپی 6 (آبان 1398)

One of the hallmarks of any country's economic development is the completion of development plans optimally at the lowest cost and most profit.The goal of success in residential projects is to reduce costs and time, increase quality and customer satisfaction. The method of data collection was library-based. Then, by reviewing the research background and interviewing the contractors, the factors affecting the success of Mehr Housing Projects were investigated. Residents were also considered important factors in their view. This set of data was analyzed to determine the factors affecting the success of these projects and then the importance of each of these indicators and their correlation was shown in the success of these projects in order to develop a proposal for future housing projects such as Present a national action plan to achieve their success. Outputs from the statistical analysis of this study show that from the contractors' point of view, indicators such as project financing guidelines, labor supply, materials and machinery, senior management support, and project team members qualifications. , The presence of responsible, experienced and expert people Employer idleness is more important in issuing approvals and approvals and enforcing contractual obligations. Also, from the point of view of residents, features such as timely delivery, consideration of project site conditions in natural disasters (floods, storms, etc.) provide Making the necessary divisions, adapting the infrastructure to the family population, and ease of access are more important.

The expansion of knowledge on how fibers affect mortar has led to recommendations for structural design. In this study, the effect of HPFRCC on the performance of reinforced concrete beams with and without polypropylene fibers on the energy absorption and hardness of the specimens was investigated. In this regard, a reference beam and four beams reinforced with a thin layer of HPFRCC in the lower part of the beams with polypropylene fibers were tested under a four-point bending test and the effect of reinforcement on energy absorption and hardness was investigated and compared.

The study was conducted using a laboratory approach in which five full reinforced concrete beams were subjected to four-point loading tests. One of the beams is selected as a reference sample and the other four beams are reinforced at the lower surfaces of the concrete beams with a layer of HPFRCC material, and the bending behavior and the ductility of the beams are compared. The highest plasticity occurs in beams reinforced with HPFRCC 1-2 samples (BH-1 sample) and (BH-2 with a 41% increase over the reference sample) due to the higher ultimate tensile strain of these reinforced materials than conventional concrete and utility system performance. In samples with 1% fibers an average of 23% increase in flexural capacity and in 3% of fibers an average of 26% increase in flexural capacity.

Concrete structures Projects under construction near wetlands cause harmful substances to enter the wetland and thereby escape or death of animals, wetland accumulation from artificial sediments, chemical change of water, etc. Using pozzolans as well as environmentally friendly concrete is a good way to reduce harmful substances.. In this research conducted in Anzali International Wetland, the effect of constructing concrete foundations along the road of Anzali port on the pollution of the wetland was investigated and the amount of chemical changes of the sample prepared in the wetland water by different concrete, one concrete made with Portland cement and another Portland blend concrete and fused micro-silica gel. The results of this study showed that by reducing the concrete content of 8% and adding the same percentage of fused micro-silica gel to the concrete volume of the bridge bridges, while increasing the bridge's resistance, Biodiversity and pollution of the wetland water also occurred in the environmental assessment of the bridges Concrete and metal found that it is more suitable to produce less pollutants in the process of manufacturing metal bridges. Addition of fiber-reinforced silica gel resulted in less change in the chemical quality of water than in cement-based concrete, and only due to the presence of silica, the amount of silicon element was greater than that of cement-based concrete.