An infill development of the process of urban developing and reusing empty or unused parts or sections of existing urban areas that have already been developed. the infill development, which may be considered as the simplest interpretation of endogenous development, tends to extend development on these lands, with emphasizing the abandoned and empty intra-city lands. Current research with an analytical approach in the infill development with the emphasis on the 8th district of Tabriz Municipality and utilizing statistical-spatial methods has been get involved to this issue. This kind of research is known as descriptive-analytical. the methodology of this research is based on quantitative-spatial approaches. the research method used in this study is a combination of documentary-library methods. in the analytical section, considering the indicators and requirements of infill development in the form of 16 target indicators, the case study and feasibility of infill development in Tabriz 8th district have been discussed. in the current study, to investigate and analyze the strategic role of infill development in regeneration of the urban texture worn of the historical-cultural axis of the metropolitan city of Tabriz, utilizing the geographical information system (GIS) software and Overlapping Functional Analysis, type of weighted overlay and FAHP is done. The results of present study are presented in the form of three priority development plans as well as unauthorized developmental areas.

Social sustainability today, as the most important dimension of sustainable development, has an important place in urban planning and its importance in planning is constantly increasing with the increase of social problems and divergence between neighborhoods in terms of performance and participation. Therefore, this requires more research in urban studies. This study was conducted to investigate the role of social participation in the development of social sustainability in neighborhoods. For this purpose, the significance of the significant effect of these two variables has been measured. The research is applied in terms of purpose and descriptive-analytical in terms of method. Data collection was library and field method. The statistical population of the study consists of a group of experts who were selected by the available method of 20 people as the sample size of the study. Data collection tool is a questionnaire based on theoretical foundations and studies conducted on a five-point Likert scale. Data analysis was performed using structural equations with the help of Emus software. The results showed that the social participation of citizens in neighborhoods with a coefficient (beta) of 0.732 has a positive effect on sustainable social development of these neighborhoods and the relationship between these two variables is significant. In other words, sustainable social development will be strengthened by strengthening social participation. And the variables of sense of belonging, satisfaction with the neighborhood, participation in neighborhood activities and trust also have a positive effect on the variables of social participation in neighborhoods.