Settlement of Sands
Calculating the settlement of a building footing, a bridge abutment, a bridge approach fill, a machine foundation, a landfill cover or a concrete dam are a few of the areas where settlement calculations are required. If your client cares about the performance of his structure, he will definitely want to know how much settlement or differential settlement it is anticipated to experience. I know from my experience as a structural engineer that my first request of the geotechnical engineer was an allowable bearing pressure value to use in sizing and designing concrete footings. After I had sized my footings, I needed an estimate of anticipated settlements to use in my structural steel frame model. Foundation settlements were very important in that model because settlements impacted redistribution of loading in the structural members. Calculation of settlements is an important part of geotechnical engineering practice, and it is one of the most difficult problems to tackle. How accurately must the settlement prediction be determined, and do we need to include time rate of settlement estimates? Settlement predictions are another case where the graded approach to problem solution is required.
When I took graduate geotechnical courses in the late 1960s, we calculated total foundation settlement as the sum of immediate settlement plus consolidation settlement plus secondary compression settlement. This total settlement calculation was assumed ...