March 1, 2017 - ASCE Geotechnical Group Dinner Meeting

Limit Equilibrium Design Framework for MSE Structures with Extensible Reinforcement

SPEAKER:

Dr. Dov Leshchinsky and Ora Leshchinsky, PE, ADAMA Engineering, Inc.

ABSTRACT: The FHWA has published in December 2016 a report titled "Limit Equilibrium Design Framework for MSE Structures with Extensible Reinforcement" (FHWA-HIF-17-004). This report, co-authored by the presenters, presents a methodology using a unified design approach for internal, external, compound, and global stability of geosynthetic-reinforced walls and slopes. It considers design of reinforced soil as a subset of slope stability analysis. Hence the presenter often refers to this approach as "Soil Reinforcement 101" although the technology was implemented commercially over 35 years ago and since then has been growing exponentially. The approach promotes a consistent and rational method to account for complex geometry, loading, and geotechnical conditions in the design of MSE walls. For a given problem including specified layout of reinforcement and permissible long-term strength of soil, it produces the reactive distribution of tensile force in each reinforcement layer. It also produces the required minimum load at the connection to the facing. It overcomes the disjointed analyses used in current design while rendering an assumption-free solution. Compared with AASHTO, the methodology results in much lower required force in the reinforcement and at the connection. Several instructive examples are presented illustrating aspects such as effects of facing units, closely spaced reinforcement, short secondary reinforcement layers, earthquake loading, and complex geometries.

BIOGRAPHY: Professor Emeritus Dov Leshchinsky retired from the University of Delaware after 32 years of service. At the University of Delaware he conducted research on slope stability, soil reinforcing, geosynthetics and dredged materials. The National Science Foundation, US Army Corps of Engineers, Federal Highway Administration and private industries have sponsored various research projects he has conducted. Much of his work has focused on comprehensive design methods for geosynthetic reinforced steep slopes and walls as well as geotextile tubes. He has published numerous referred papers in leading geotechnical journals. Dr. Leshchinsky has co-developed well-known design-oriented computer programs partially sponsored by FHWA and USCOE: FoSSA, ReSSA, MSEW, ReSlope, GeoCoPS.

Dr. Leshchinsky is currently a consultant in ADAMA Engineering, Inc. Governmental agencies, geotechnical outfits, geosynthetic manufacturers, and law firms had retained him as an expert. He has been involved with two complex, large projects dealing construction over soft soil (i.e., Woodrow Wilson Bridge on the Maryland side of the Potomac River and Cherry Island Landfill in Delaware). He co-developed an NHI short course on Slopes and Embankments. He has been co-teaching short courses on MSE Walls Reinforced Soil Slopes, Shallow Foundations, Slopes and Embankments, and Geosynthetic Reinforcement. Dr. Leshchinsky has served on various editorial boards (e.g., ASCE Journal of Geotechnical Engineering; Geotextiles and Geomembranes; Soils and Foundations). He had also served on various committees such as HITEC. He was invited to deliver keynote presentations in several national and international geotechnical events.

Ora Leshchinsky holds a B.Sc. in Civil Engineering and a Master of Architecture degree. Ora is a registered professional engineer (PE) in the State of Delaware and has over 35 years of experience as a practicing engineer and as a university instructor of basic courses in engineering. Ora's graphical abilities, enhanced by her Architectural studies, combined with engineering practice and teaching makes her uniquely qualified to conceptualize and develop computer routines that make visualization of numerical results easier. Her main contribution to ADAMA's software relates to the architecture and development of the code of its computer programs. Ora is the chief programmer of ADAMA Engineering.

Register online using the "Register Now!" button below or email Seth Reddy at sreddy@gri.com by Friday, February 24th, 2017.

This month, dinner will start promptly at 7 pm and a sound system will be used! Last month was a trial-run at a new venue, and we thank you for your patience. If RSVP-ing via email, please include one of the following meal options per registrant: (1) Chicken Marsala, (2) Sicilian Meatballs, (3) Spaghetti with Mushroom. Guests may also order coffee or tea paid for by the group. Late registrations will be accepted up to Monday, February 27th at noon, but a $10 late fee ($5 for students) will be assessed for any reservation made after Friday. Cancellations within 10 days of the event will incur a fee equal to the registration fee.