In the current state of practice, any soil settlement other than consolidation settlement is often called elastic settlement. It is also referred to as immediate settlement in some geotechnical reports. The question is: which one of these terminologies is more appropriate and better represents the nature of soil deformations. Unlike steel or aluminium, soil exhibits… Read More
Boundary condition at base of a finite element/difference model can significantly affect outputs of a seismic analysis. The key to find out what base boundary condition suits our numerical model is to find out whether the earthquake motion to be applied at the base of our model is “outcrop motion” or “within motion”. Outcrop motions… Read More
The worldwide state of practice for simulating static and seismic soil-pile interaction is to use a set of one-dimensional springs along pile shafts. This approach is also referred to as Beam on Nonlinear Winkler Foundation (BNWF). Due to its simplicity, the method is widely used in almost all engineering firms around the world for the… Read More
Approach of Boulanger and Idriss (2014) for liquefaction analysis requires performing iterations to determine and . In case you need to develop an excel spreadsheet that evaluates liquefaction based on Boulanger and Idriss (2014) approach, you may need to use the Macro below. Please note that based on my personal experience Excel’s built-in iteration module does… Read More
A few months ago, I was involved in a very interesting and challenging project in Bay Area, California. A portion of this project was to evaluate seismic performance of an existing wharf structure located at the project site. The subsurface soil consisted of loose silty sand fill underlain by up to 25ft deep soft young bay… Read More
Geotechnical engineers use footing allowable bearing pressure as the input load for the estimation of consolidation settlement, a.k.a long-term settlement. It is to be noted that the allowable bearing pressure includes 100% of dead load (D) and 100% of live load (L) . However, ASCE 7-10 allows to use smaller loads for calculation of long-term… Read More