Geotechnical Report for Gardez to Khost Bridge No. 9, Afghanistan

9 in Afghanistan is a 38.46 m bridge project that includes a culvert and retaining wall. The bridge is located along the Gardez to Khost Road, at KM = 50+019.974 to 50+058.453. The site project area is situated on P2 csh Clay and shale (Eocene) geological formation, which consists of clay, shale, siltstone, and sandstone. The geotechnical site assessment was conducted by KA Labs to provide recommendations for the design of foundations and other geotechnical aspects of the proposed construction. The scope of work included conducting a subsurface investigation, basic laboratory testing of select soils, and a geotechnical engineering analysis using the information obtained from the subsurface investigation and laboratory testing. The subsurface investigation involved drilling nine boreholes to a depth of 8 meters below the existing ground surface, with five boreholes drilled at the footing of the bridge, two boreholes drilled for the retaining wall, and two boreholes drilled for the culvert. Soil sampling, field density testing, and laboratory soil tests were performed to determine the engineering characteristics of the subsurface materials. The results of the subsurface investigation and laboratory testing indicate that the site project area consists of various soil types, including CL-ML, SM, GM, GC-GM, GW, GP, and GW-GM, according to the Unified Soil Classification System. The site is located in a seismically active area, with moderate to strong earthquakes occurring frequently in the region. The seismic hazard map of Afghanistan shows that the likelihood of strong shaking in the next 50 years is highest in northeastern Afghanistan and along the corridor adjacent to the Chaman fault system. The proposed bridge project is located in an area with a moderate to high seismic hazard, and the design of the bridge should take into account the potential for seismic activity. The geotechnical report provides recommendations for the design of the bridge foundations and other geotechnical aspects of the proposed construction. The report includes recommendations for site preparation, excavations, structural fill, and geotechnical engineering aspects of the project. The report also discusses the limitations of the geotechnical investigation and the potential risks associated with the project. The proposed bridge project is a critical infrastructure development that will improve transportation connectivity between Gardez and Khost. The geotechnical report provides essential information for the design and construction of the bridge, and its recommendations should be carefully considered to ensure the safety and stability of the structure.