Experimental Design and Workplan to Study

THE EFFECTIVENESS OF RETICULATED MICROPILERETICULATED MICROPILE

GROUPS

Dr. James A. Mason, P.E.University of Tennessee

K illKnoxville

PRESENTATION TOPICSPRESENTATION TOPICS• Review of reticulation• Review of reticulation

strengthening as developed by Dr Fernando Li iDr. Fernando Lizzi

• Overview of “Experimental pDesign & Workplan to Study The Effectiveness of ReticulatedThe Effectiveness of Reticulated Micropile Groups”, Kulhawy & Mason 1995Mason 1995

PRESENTATION TOPICSPRESENTATION TOPICS

• Proposed Lizzi Center for R ti l ti R h t thReticulation Research at the University of Tennessee, y ,Knoxville

STRENGTHENING of HISTORIC STRUCTURES

withwithRETICULATED

REINFORCEMENT

METHODS DEVELOPED BYO S V ODr. FERNENDO LIZZI

ISM Washington, DC

2010

THE PHILOSOPHY.

LIZZI AND THELIZZI AND THE DEVELOPMENT OF

THE INTERNAL REINFORCEMENTREINFORCEMENT

METHOD (IRM) AND ( )RETICULATED

MICROPILES (RRP)MICROPILES (RRP)

Primum non nocerePrimum non nocere. First, do no harm.First, do no harm.

Dr. Fernando Lizzi.

ISM Washington, DC 2010

THE 4 GENERAL CATAGORIES OF IRM & RRP STRENGTHENING

St ti R t ti f• Static Restoration of Monuments.

• Strengthening of Subsoil in Urban AreasUrban Areas.

• Strengthening of Structures for S i i ESeismic Events.

• Strengthening of Towers.ISM Washington, DC

2010

Strengthening of Towers.

LIZZI’S BASIC PHILOSOPHY OF RRP & IRM TECHNOLOGY

• MAINTAIN EXISTING EQUILIBRIUM.• REINFORCE both the soil & the existingREINFORCE both the soil & the existing

structure, (smooth stiffness transition along the complete length of structure)along the complete length of structure).

• STRICTLY PRESERVE the construction scheme and original aesthetic designed by the original architect / engineer.

ISM Washington, DC 2010

g g

• INTEGRATED FOUNDATION TOFOUNDATION TO TOWER SYSTEM.ENCASED SOIL• ENCASED SOIL MASS ADDITIONAL ELEMENT OF RESISTANCE TO OVERTURNING.

• SMOOTH• SMOOTH STIFFNESS GRADIENT.

WHY RETICULATIONWHY RETICULATION• Lizzi had always envisioned the

reticulated root pile system to encompass and engage the p g gsurrounding soils as the major component to load resistance, morecomponent to load resistance, more than the micropiles themselves.S il R i f D L d• Soil Reinforcement vs. Deep Load Transfer

WHY RETICULATION

• “It is has been said before, about “Pali Radice” that their highPali Radice , that their high bearing capacity compared with their small diameter is the mosttheir small diameter is the most favorable characterizing element.

WHY RETICULATIONTh f h d• Therefore, the tendency arose to increase the metal reinforcement to obtain more resistant sections. Finally micropiles consistingFinally, micropiles consisting substantially of very heavy metal pipes which would bear considerably high loads, were introduced.high loads, were introduced. Practically, they are pipes cemented i t th b il ” Li i (1982)into the subsoil.” Lizzi (1982)

WHY RETICULATION

• Stitching of soil, rock, i i ibuilding, bridge, and tower

into a continuous internallyinto a continuous internally reinforced structure.

Drilled and Grouted Micropiles: State of the Practice

Bruce and Juran (1995)Bruce and Juran (1995)• Originator and director: Dr. Al

DiMillio.• Advisory Board: Lizzi, Schlosser,Advisory Board: Lizzi, Schlosser,

Frank, Herbst, Turner, Bjorhovde, Zelinski Chassie Lukas KulhawyZelinski, Chassie, Lukas, Kulhawy, and Mason.

Bruce and Juran (1995)SUGGESTED RESEARCHSUGGESTED RESEARCH NEEDS for NETWORKS of

MICROPILESMICROPILES

“S l t t f h t t• “Several tests of such structures have been conducted over the years, but systematic further testing and reanalyses of the old tests are yrequired.

• What is the most appropriate design• What is the most appropriate design methodology?

OVERVIEW of“The Effectiveness of Reticulated

Micropile Groups”Micropile Groups

STATEMENT OF WORKSTATEMENT OF WORK

• Conduct a literature search to define• Conduct a literature search to define the state of experimental work,

l ti l l i d li d d ianalytical analysis, modeling, and design of reticulated micropile groups

Statement of Work, cont.• Provide an overall workplan for

an experimental and analyticalan experimental and analytical research program using small-scale physical modelsscale physical models

• Develop an experimental program to determine how reticulated micropile groups p g pwork and why they are more efficient than conventional pileefficient than conventional pile systems

PROPOSED LOAD TESTS• The scope of this proposed study

ill f th b iwill range from the basic components of the reticulated group to the complete system, i e from individual micropiles toi.e., from individual micropiles to the reticulated micropile group.

• All tests will be conducted in drained sands at loose mediumdrained sands at loose, medium, and dense states.

PROPOSED LOAD TESTS

• In addition to investigating the performance of the variousperformance of the various components in the 3 density states, the influence of element spacing will beinfluence of element spacing will be tested for the interaction of the basic multiple element componentsmultiple element components.

• By investigating the spacing h f th t t tiphenomena for these tests, optimum

spacing conditions will be defined for th t f th t tthe rest of the tests.

Performance Tests of

ReticulatedReticulated Micropile

Group Components:Components:

The Node

Performance Tests of Reticulated Micropile Group Components:

The Soil DiamondThe Soil Diamond

The Quilt

The RRP SystemSystem

LIZZI CENTERfor

RETICULATIONRETICULATION RESEARCH

U i it f TUniversity of TennesseeKnoxville

OBJECTIVES

• Detailed understanding of performance and design of IRMperformance and design of IRM and RRP strengthened structures using an integrated structural and geotechnicalstructural and geotechnical perspective, all in 3-dimensional space.

OBJECTIVES

• Testing and analysis will be developed through basic mechanicsdeveloped through basic mechanics and first order principals

i i• Parallel testing and analytical modeling will be performed through all cycles

OBJECTIVES• Coordination hub for academic,

industry, funding agencies, and y, g g ,owners for literature, experimental programs and analytical modelingprograms and analytical modeling.

• Perform basic research for RRP per Kulhawy & Mason (1995)

• Perform basic research for IRM (inPerform basic research for IRM (in development)

OBJECTIVES

• Develop guidelines for testing, design construction methods anddesign, construction methods and codification for RRP & IRM

Current Status at UTK

• Dept. of Civil & Environmental Engineering. Institute for Geotechnical EngineeringGeotechnical Engineering

• Geotechnical engineering faculty• Structural engineering faculty• Architecture & Historic

Preservation facultyy

Current Status at UTK

• Center for Transportation ResearchResearch

• Southeastern Transportation pCenterC t ti I d t R h• Construction Industry Research & Policy Centery

Potential Partners• National Science Foundation• Federal Highway Administration• Federal Highway Administration• International Society of Micropiles• Association of Drilled Shaft

ContractorsContractors• Tennessee Department of

Transportation• Tennessee Valley Authorityy y• Oak Ridge National Laboratory

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS• FHWA. Dr. Al DiMillio, Jerry

DiMaggio, Ron Chassie• Dr Donald Bruce• Dr. Donald Bruce• Dr. Ilan Juran• Dr. Fred Kulhawy• Ms Mary Ellen Bruce ISM• Ms. Mary Ellen Bruce ISM• Dr. Dayakar Penumadu UTK