On November 1, Dr. Ben Leshchinsky (Oregon State University) will present the next IGS North America webinar. His topic is one of the biggest topics in the field right now: “A Different Approach towards Limit State Design of Geosynthetic-Reinforced Soil Structures.”
This online event is FREE to industry professionals and students. It’s part of a new series of webinars jointly hosted by the Geosynthetic Materials Association and IGS North America.
Date: November 1
Time: 1:00 – 2:00 pm EST
BEN LESHCHINSKY ON LIMIT STATE DESIGN
Conventional design of geosynthetic-reinforced soil structures is divided into two categories, walls and slopes, based on the batter of the facing system. Internal stability, characterized as sufficient reinforcement anchoring and strength, is performed using earth pressure-based design criteria for reinforced walls, while reinforced slopes are founded on limit equilibrium (LE) slope stability analyses. LE analyses are also used to assess the global or compound stability of both types of structures, accounting for the geometry of the reinforced, retained, and foundation soils.
The application of LE-based methods typically results in determination of a slip surface corresponding to the lowest attained Safety Factor (SF), known as the Factor of Safety (Fs); however, it yields little information about reinforcement or connection loading.
In this presentation, Dr. Ben Leshchinsky will show how the use of the analyzed spatial distribution of SF (known as a Safety Map) can be modified to attain a prescribed constant Fs at any location in the reinforced soil mass. This modified framework directly enables the determination of a Tension Map that illustrates the required distribution of reinforcement tension to attain a prescribed state of equilibrium. To illustrate the utility of the Limit State framework, a series of instructive examples will be presented. The results of this design approach demonstrate the effects of facing elements, closely-spaced reinforcements, and secondary reinforcement layers. Comparison will also be provided to conventional design approaches.
Ben Leshchinsky, Ph.D., P.E. is an associate professor in geotechnical engineering at Oregon State University. His primary research interests focus on slope stability, reinforced soil, and applications of geomechanics towards assessment of natural hazards.0