BE AWARE THIS IS A FOUNATION ENGIEERING PROBLEM AND THE QUESTIONS NEEDED TO BE ANSWERED ARE UNDER THE "Your Job" CATEGORY ON THE SECOND PICTURE

1001 100 Bridge -pier AN Allan a butment Schematic Cross section 1 = 41 Twin river bridges will be constructed (northbound & southbound), each with 3 lanes. The bridges will be built one at a time. We will look at the first of these bridges. The proposed bridge is a 2-span structure with a center pier in the river and abutments at the north and south ends. The spans have length of about 100'each, with total length of about 200'. The bridge has width of about 42'. Based on available information and site observation, the river is approximately 80' wide and 5' deep under normal flow conditions. The river banks are about 25' high. The distance between the top-of- banks is about 180'. Preliminary loads are estimated to be on the order of 2,000 to 2,500 kips at the abutments and 2,500 to 3,500 kips at the pier. Desk Top Study & Field Reconnaissance Summary: Some bare soil is visible in the banks, indicating silty sand on the north and silt/clay on the south. The project is in an area known for variable subsurface conditions. Based on local knowledge, it is anticipated that dense soils occur at a depth of about 30' below river bottom. Depth to rock is not known; assume 80' below river bottom (note that this is reachable using a typical drill rig). Your Job Develop a subsurface investigation program for the project. Because the type of foundation is unknown at this time, the investigation should be adequate for design of either shallow spread footing foundations or deep (pile) foundations. For guidance, refer to excerpts from AASHTO specifications and the NY State DOT geotechnical design manual. (It's not, but assume the bridge is in upstate NY.) Consider: O . Based on AASHTO guidance, how many borings? How Deep. Provide a sketch showing proposed boring locations and depths (1.5 points) Same as above, using NYS DOT guidance (1.5 points) What type of sampling should be performed? Frequency of sampling? (0.5 points) What type of lab testing should be performed? (0.5 points) . . Be neat, logical, and concise. Provide assumptions as needed. 1001 100 Bridge -pier AN Allan a butment Schematic Cross section 1 = 41 Twin river bridges will be constructed (northbound & southbound), each with 3 lanes. The bridges will be built one at a time. We will look at the first of these bridges. The proposed bridge is a 2-span structure with a center pier in the river and abutments at the north and south ends. The spans have length of about 100'each, with total length of about 200'. The bridge has width of about 42'. Based on available information and site observation, the river is approximately 80' wide and 5' deep under normal flow conditions. The river banks are about 25' high. The distance between the top-of- banks is about 180'. Preliminary loads are estimated to be on the order of 2,000 to 2,500 kips at the abutments and 2,500 to 3,500 kips at the pier. Desk Top Study & Field Reconnaissance Summary: Some bare soil is visible in the banks, indicating silty sand on the north and silt/clay on the south. The project is in an area known for variable subsurface conditions. Based on local knowledge, it is anticipated that dense soils occur at a depth of about 30' below river bottom. Depth to rock is not known; assume 80' below river bottom (note that this is reachable using a typical drill rig). Your Job Develop a subsurface investigation program for the project. Because the type of foundation is unknown at this time, the investigation should be adequate for design of either shallow spread footing foundations or deep (pile) foundations. For guidance, refer to excerpts from AASHTO specifications and the NY State DOT geotechnical design manual. (It's not, but assume the bridge is in upstate NY.) Consider: O . Based on AASHTO guidance, how many borings? How Deep. Provide a sketch showing proposed boring locations and depths (1.5 points) Same as above, using NYS DOT guidance (1.5 points) What type of sampling should be performed? Frequency of sampling? (0.5 points) What type of lab testing should be performed? (0.5 points) . . Be neat, logical, and concise. Provide assumptions as needed