12 Sep 2022

Stability Analysis of Old River Low Sill Structure

Abstract: An updated stability analysis was performed on the Old River Low Sill Structure due to a change in the operating conditions from historic river sedimentation. Sedimentation of the Mississippi River channel since the 1973 spring flood has caused higher river stages at lower discharges. Numerical methods used included nonlinear analysis of pile group stability, seepage analyses, and limit equilibrium methods. The structure’s foundation was compromised during the 1973 flood, and emergency repairs were conducted to prevent scouring and undermining of the foundation by the flood scour. Rehabilitation included the reconstruction of a failed wing wall on the left abutment, rock and riprap fill in the forebay channel, and emergency grouting to fill the scour hole beneath the structure. An operating restriction was emplaced to limit the differential head across the structure due to flood damage. Taking these conditions into account, results from an updated analysis showed that full headwater uplift caused increased tension in the piles, while the increased body load caused increased compressive loads in the piles. Review of piezometric monitoring and the seepage analyses showed that full headwater uplift is unlikely, indicating the foundation grouting adequately sealed the scour hole beneath the structure. Analysis results exhibited lower magnitude compression and tension loads in the piles with design load cases compared to previous analyses. Recommendations from these analyses indicate that increased monitoring and additional investigation may support increasing the differential head limitation.

26 Aug 2021

Sustainable Infrastructure in Conflict Zones: Police Facilities’ Impact on Perception of Safety in Afghan Communities

Abstract: The notion of sustainable infrastructure for the delivery of social services is to fulfill basic human needs; in war-torn societies, human safety is a critical basic need. The relationship between sustainable infrastructure development and human safety remains under-researched in Afghan neighborhoods. Therefore, this study examined the effectiveness of the police facilities constructed for stability enhancement in Afghan communities. To do so, this study used Afghans’ polling datasets on the police presence and the public safety perceptions, including newly collected survey data related to the influence of the police facilities on human safety and other factors contributing to the neighborhoods’ well-being. The datasets are organized with a multilevel structure in which different individuals are sampled within neighborhoods and analyzed using a multilevel model approach to capture the randomness of the responses. The results showed that police facilities are more important to perceptions of safety in less safe areas and that Afghans in villages perceived themselves as safer than in urban areas, relative to their own immediate region. Those perceiving themselves as being safer were older, more highly educated, and widowed respondents. Overall, Afghans perceived the police facilities as institutional symbol for promoting improvements and opportunities for fulfilling basic human safety need.