practical shoring systems presentation

8/13/2019 Practical Shoring Systems Presentation

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SystemsSystems

Prepared By: Dr. Amjad BarghouthiPrepared By: Dr. Amjad Barghouthi

Re ional Mana er Re ional Mana er

ACESACES


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11..00 IntroductionIntroduction

severalseveral situationssituations inin constructionconstruction.. TheThe constructionconstruction ofof deepdeepbasementsbasements requiresrequires shoringshoring systemssystems toto retainretain thethe toptop soilsoil // fillfill

materialsmaterials downdown toto thethe competentcompetent rockrock depthdepth..

OneOne problemproblem thatthat appearsappears alwaysalways isis thatthat thethe designerdesigner utilizesutilizes

systemsystem..

considerationconsideration ofof thethe necessitynecessity ofof aa shoringshoring systemsystem..


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andand utilizedutilized shoringshoring systemssystems thatthat willwill notnot taketake significantsignificant spacespacefromfrom thethe landland areaarea andand havehave provedproved veryvery feasiblefeasible systemssystems forfor fillfill

// toptop soilsoil heightsheights fromfrom 331515mm..

TheThe systemssystems areare::

11.. Soldier Piles and Rock Nails. The soldier piles areSoldier Piles and Rock Nails. The soldier piles are

constructed at an angle ofconstructed at an angle of 77oo 99oo with the vertical.with the vertical.

22.. SoilSoil Nailing.Nailing.


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22..00 Soldier Piles and RockSoldier Piles and Rock NailsNails

The main components of the system shown in FigureThe main components of the system shown in Figure 11 are:are:

II.. GroundGround / Rock Nails / Anchors/ Rock Nails / Anchors

TheThe employedemployed systemsystem usesuses groundground nailsnails thatthat consistconsist ofof

reinforcementreinforcement barsbars usuallyusually 3232mmmm inin diameterdiameter installedinstalledtoto thethe re uiredre uired len thlen th inin holesholes ofof diameterdiameter 1010 1515cmcm

andand thethe bondedbonded lengthlength isis groutedgrouted byby cementcement groutgroutusuallyusually withwith nonnon--shrinkshrink additivesadditives.. TheseThese nailsnails areare

usuallyusually anchoredanchored inin rockrock hence,hence, thethe namename althoughalthough theythey

areare notnot prepre--stressedstressed.. TheThe steelsteel barsbars areare justjust tightenedtightened

andand lockedlocked inin placeplace..


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FigureFigure 11: Soldier Piles and Rock: Soldier Piles and RockNailsNails


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UsuallyUsually steelsteel II oror HH beamsbeams areare installedinstalled inin prepre--drilleddrilled

..

steelsteel beamsbeams asas alsoalso groutedgrouted toto fixfix itit inin rockrock..

III.III. Waler Waler BeamsBeams

WalerWaler beamsbeams usuallusuall consistconsist ofof twotwo steelsteel channelschannels

installedinstalled atat thethe anchoranchor locationslocations..


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Several options for lagging may be used:Several options for lagging may be used:

11. Steel. Steel PlatesPlates

ThicknessThickness ofof thethe platesplates maymay bebe asas smallsmall asas 33mmmm..

thesethese steelsteel platesplates areaarea reinforcedreinforced withwith steelsteel anglesangles atatcertaincertain intervalsintervals..

22. Wood. Wood LaggingLagging

WouldWould purlins may also be usedpurlins may also be used..


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TheThe connectionconnection consistsconsists ofof steelsteel plateplate andand nutnut atat thethe

..

toto designdesign..


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22..22..11 MethodologyMethodology

TheThe designdesign basesbases isis similarsimilar toto anyany shoringshoring systemsystem inin

termsterms ofof analysisanalysis andand distributiondistribution ofof bendingbending momentsmomentsandand shearshear forcesforces toto anchors,anchors, walerswalers,, andand soldiersoldier pilespiles..

EarthEarth ressureressure includinincludin surchar esurchar e loadsloads andand anan

waterwater pressure)pressure) cancan bebe selectedselected basedbased onon thethe wellwell--establishedestablished PecksPecks RulesRules..


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thatthat thethe maximummaximum forcesforces areare transmittedtransmitted toto thethe lowerloweranchorsanchors (usually(usually wellwell embeddedembedded inin rock),rock), activeactive

conditionsconditions havehave beenbeen usedused successfullysuccessfully inin allall designeddesigned

projectsprojects.. ThisThis approachapproach hashas beenbeen verifiedverified byby plaxisplaxisanalysisanalysis (finite(finite element)element) andand byby actualactual monitoringmonitoring ofof

displacementsdisplacements atat severalseveral sitessites..

AnAn excelexcel sheetsheet hashas beenbeen developeddeveloped specificallyspecifically forfor thisthiss stems stem andand hashas beenbeen usedused inin allall ro ectsro ects.. HandHand

calculationscalculations toto verifyverify thethe designsdesigns areare alsoalso usedused..

deformationsdeformations ofof thethe systemsystem asas wellwell asas thethe settlementsettlement ofof

thethe groundground..


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22..22..22 DesignDesign ParametersParameters

1.1. Height of fill / top soil H in m.Height of fill / top soil H in m.

.. , ., .

3.3. Surcharge loads.Surcharge loads.

4.4. Spacing between soldier piles.Spacing between soldier piles.5.5. Yield stress of steel.Yield stress of steel.

6.6. Hole diameter.Hole diameter.

7.7. Yield stress of steel bar for anchors.Yield stress of steel bar for anchors.

8.8. Allowable stresses for grout (grout / soil and grout /Allowable stresses for grout (grout / soil and grout /

steel).steel).

.. . .

10.10. Properties of steel plates and steel angles.Properties of steel plates and steel angles.


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11.. Active earth pressure is calculated using the firstActive earth pressure is calculated using the first 33

, , ., , .

22.. Analysis and Design:Analysis and Design:

a)a) CheckCheck thethe cantilevercantilever momentmoment..

..

c)c) SelectSelect sectionsection forfor largestlargest (moment(moment spacing)spacing)..

d)d) DesignDesign steelsteel platesplates basedbased onon averageaverage

max mummax mum momenmomen ..


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f)f) DetermineDetermine forcesforces inin anchorsanchors basedbased onon tributarytributaryareasareas..

gg

lengthlength ofof anchorsanchors determinedetermine thethe totaltotal lengthlength..

h)h) DetermineDetermine thethe diameterdiameter ofof holehole..


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TheThe forcesforces inin anchors,anchors, bendingbending momentsmoments cancan bebe

..

thosethose calculated,calculated, determinedetermine deformationdeformation ofof thethe

structurestructure andand settlementssettlements ofof thethe groundground..

NoteNote thatthat plaxisplaxis requirerequire thethe propertiesproperties ofof rockrock forfor thethe

modelmodel.. ItIt alsoalso showsshows thethe deformationsdeformations inin rockrock..


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.. ..

TheThe shownshown exampleexample showsshows thatthat therethere isis aa goodgood matchmatch

calculationcalculation..

ThisThis systemsystem requiresrequires competentcompetent rockrock atat aa depthdepth..


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33..00 Soil NailingSoil Nailing SystemSystem

The main components of the system shown in FigureThe main components of the system shown in Figure 22 are:are:

I.I. Soil NailsSoil Nails

TheThe soilsoil nailsnails areare holesholes drilleddrilled intointo thethe groundground withwith

diameterdiameter rangingranging fromfrom 100100 200200mmmm toto thethe designdesign lengthlength..AA steelsteel barbar ofof thethe desi neddesi ned diameter,diameter, usuallusuall 2020 3232mm,mm,

isis installedinstalled atat thethe centercenter ofof thethe holehole withwith thethe helphelp ofofspacersspacers.. TheThe holehole isis fullyfully groutedgrouted.. TheThe soilsoil nailsnails areare

generallygenerally spacedspaced atat 11..00 22..00mm horizontallyhorizontally andand verticallyvertically..


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..

ShotcreteShotcrete withwith thicknessthickness varyingvarying fromfrom 100100 150150mmmm areare

..

strengthstrength isis usuallyusually 3030N/mmN/mm22 atat 2828--daysdays..

III.III. WalerWaler BarsBars

UsuallUsuall 22--horizontal andhorizontal and 22--vertical steel bars are used asvertical steel bars are used as

wailers connecting the nails. The common size used iswailers connecting the nails. The common size used is1818mm.mm.


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..

OneOne layerlayer ofof wiremeshwiremesh isis requiredrequired forfor thethe shotcreteshotcrete.. InIn

,,

ofof wiremeshwiremesh maymay bebe usedused..

V.V. ConnectionConnection

AA latelate andand notnot isis re uiredre uired atat thethe endend ofof steelsteel barbar onon toto

ofof thethe walerwaler barsbars..


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ing

ing

Nail

Nail

So

il

So

il

ical

ical

:Ty

:Ty

ure

uretion

tion

F

ig

F

ig

S

e

S

e


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(The(The DesignDesign BasisBasis areare AdoptedAdopted fromfrom ManualManual forfor DesignDesign &&

.. ..

DepartmentDepartment ofof TransportationTransportation FederalFederal HighwayHighway

Administration)Administration)..

TheThe basicbasic designdesign conceptconcept isis toto reinforcereinforce thethe soilsoil.. DueDue toto thethe

interactioninteraction betweenbetween andand thethe soilsoil aa tensiontension loadload isis developeddeveloped

..

loadsloads oftenoften consideredconsidered asas dividingdividing thethe soilsoil massmass intointo twotwo

separateseparate zoneszones;; anan activeactive zonezone closeclose toto thethe facingfacing wherewhere

groundground andand aa resistantresistant zonezone wherewhere thethe shearshear stressesstresses areare

directeddirected inwardinward andand tendtend toto restrainrestrain thethe reinforcementreinforcement..


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Ultimate Pullout ResistanceUltimate Pullout Resistance QuQu

uu = n t t mate on stress x= n t t mate on stress x

Ultimate bond stressUltimate bond stress CohesionlessCohesionless soilssoils


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NailsNails areare usuallyusually drilleddrilled atat anan angleangle ofof 1515oo.. TheThe toptop rowrow

..

usuallyusually atat 00..7575mm..

Factors to consider in design:Factors to consider in design:

1.1. S acin of Nails and An le.S acin of Nails and An le.

2.2. Nail Length and Hole Diameter.Nail Length and Hole Diameter.

3.3. ThicknessThickness ofof ShotcreteShotcrete and Details ofand Details of WiremeshWiremesh..

unc ng ear an omen apac yunc ng ear an omen apac y

4.4. Plate ThicknessPlate Thickness..


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44..00 ConclusionsConclusions

of space for the shoring works in addition it:of space for the shoring works in addition it:

aa . .

b)b) Does not require heavy machinery to construct.Does not require heavy machinery to construct.

c)c) Does not require great experience in installation.Does not require great experience in installation.


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practical shoring systems presentation

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