Reinforced Concrete Wall Design Basics - Wisconsin Land Water
Reinforced Concrete WallDesign BasicsMike O’Shea, P.E.
Structural Concrete Design Requirements “American Concrete Institute Building Code Requirements forStructural Concrete (ACI 318)” which is referenced in NRCSConservation Practice Standard 313 – Waste Storage Facility.
Typical Structural Concrete Wall Loadings Lateral Soil Backfill Loads (depends on soils type) Lateral Equipment Loads Vertical Wall Loads (structural slab or push-off ramp bearing ontop of wall) Lateral Manure Loads
Structural LoadingsCommon External Loadings Backfill pressure Equipment LoadsCommon Internal Loadings Manure Fluid PressureOther Loadings to Consider Impact LoadsHydrostatic Pressure (Lateral and Uplift)Internal Ice Pressures (Lateral)Frost Pressure (Lateral and Uplift)
STABILITY VS. STRENGTH DESIGN STABILITY DESIGN OVERTURNING SLIDING BEARING PRESSURESTABILITY DESIGNUSES ACTUAL LOADSAND SAFETY FACTORSAND ASSUMES THEWALL AND FOOTINGARE INFINITELY STIFF
STABILITY VS. STRENGTH DESIGN STRENGTH DESIGN BENDINGSHEAR(TORSION)(BUCKLING)STRENGTH DESIGN USES: LOAD FACTORS AND STRENGTH REDUCTIONFACTORSRATHER THAN “SAFETYFACTORS”
STRENGTH DESIGNEXAMPLE OF ONE FACTORED LOAD COMBINATIONCAPACITY (STRENGTH) OFREINFORCED CONCRETESTRENGTHREDUCTION FACTORVARIES FROM 0.90FOR BENDING TO0.75 FOR SHEARLOAD FACTORSφU 1.2D 1.6H 1.6LDEAD LOADLATERAL EARTHPRESSURELIVE LOADS(EQUIPMENT)LOAD FACTOR FORBACKFILL RESISTING“FULL MANURE” CASEIS 0.90
LOAD SCENARIO 1: MAXIMUM EXTERNAL LOADS AND EMPTY INSIDEBackfill side withEquipment LoadsBackfillPressureDiagramManure side: EmptyEquipment LoadDiagram: Equivalentto an additional 2feet of uniform soilloading
LOAD SCENARIO 2: FULL INSIDE WITH MINIMUM BACKFILLBackfill side withoutEquipment LoadsBackfillHeightBackfillPressureDiagramManure side: EmptyManurePressureDiagram
WALL SUPPORTSimply Supported Wall(740 Drawing Series Tanks)Cantilevered WallFree TopFixed Base(requires either embeddedor expansive waterstop)Pinned Top(either tied to slab orsupported internally bybeams)Pinned Base(movement joint requiringembedded waterstop)
MAXIMUM BENDING STRESSES IN WALL STEMCantilevered WallSimply Supported WallTension FaceLoadTensionFaceWallmovementunder load(exaggerated)Maximum StressPoint at Wall BaseLoadMaximum StressPoint atapproximatelyMid-Height ofwallWall movementunder load(exaggerated)
MAXIMUM BENDING STRESSES IN FOOTINGSCantilevered Wall(Fixed Base)LoadTension Face HeelMaximum StressPoint in Footing isat Face of WallFooting movement underload (exaggerated)HeelTension Face ToeFooting movement underload (exaggerated)Toe
FOOTING BEARING PRESSURELOAD: Weight of wall and footingBackfill sideLOAD: Lateral soil andequipment surchargeBackfill weightManure side: EmptySoil BearingPressureMaximum BearingPressure
STRENGTH STEEL – CANTILEVERED “T” WALLBackfill sideStrength steel forexternal loadingWall StemManure sideStrength steel forinternal loadingFooting strengthsteelFooting
HORIZONTAL STEEL (Temperature and Shrinkage Steel)Temperature &Shrinkage SteelTemperature &Shrinkage Steel
STRENGTH OF REINFORCED CONCRETE SECTIONSWhat Determines the Strength of a Reinforced ConcreteSection (rebar and concrete acting together) ? 28 day compressive strength of concrete (f’c)3,500 or 4,000 psi minimum Grade of Rebar (fy)Usually Grade 60 (60,000 psi yield strength) Amount of rebar (As)(size and spacing) Location of Rebar relative to compressive face ofconcrete (d)Let’s take a look at these in a little more detail and see whathappens if the parameters for a particular design are notmet
STRENGTH OF REINFORCED CONCRETE SECTIONS 28 day compressive strength of concrete (f’c)If the concrete strength requirements are not met: Durability will be affected Possibly failure under high loads, particularly in thelong term when water (freeze-thaw) havedeteriorated the sand/cement matrix of theconcrete.
STRENGTH OF REINFORCED CONCRETE SECTIONS Grade of Rebar (fy)The project calls for Grade 60 and Grade 40 is used:Example: 10” thick wall3500 psi concrete2.5” clear to strength steel#5@10BENDING STRENGTH OF THE SECTION HAS BEENREDUCED BY OVER 30%
STRENGTH OF REINFORCED CONCRETE SECTIONS Amount of rebar (As)The project calls for #5@10” and #5@12” are used:Example: 10” thick wall3500 psi concrete2.5” clear to strength steel#5@12” rather than the designed #5@10”BENDING STRENGTH OF THE SECTION HAS BEENREDUCED BY ABOUT 16%
LET’S TRY THAT AGAIN A LITTLE DIFFERENTLY Amount of rebar (As)The project calls for #5@10” and #4@10” are used:Example: 10” thick wall3500 psi concrete2.5” clear to strength steel#4@10” rather than the designed #5@ 10”BENDING STRENGTH OF THE SECTION HAS BEENREDUCED BY ABOUT 35%
STRENGTH OF REINFORCED CONCRETE SECTIONS Location of Strength Rebar relative tocompressive face of concrete (d)What does “compressive face” mean?What does “strength rebar” mean?
COMPRESSIVE FACE & STRENGTH REBARCantilevered WallSimply Supported WallTension FaceLoadWallmovementunder pressiveFaceWall movementunder load(exaggerated)
COMPRESSIVE FACE & STRENGTH REBARCantilevered Wall(Fixed Base)LoadCompressiveFaceTension Face HeelFooting movement underload (exaggerated)HeelTension Face ToeCompressiveFaceFooting movement underload (exaggerated)Toe
COMPRESSIVE FACE & STRENGTH REBARCantilevered WallBackfill sideBackfill sideStrengthRebarLoadCompressiveFace of WallCompressiveFace of WallLoadStrength RebarCompressiveFace of Footing ToeCompressive Face of Footing HeelManure SideCompressive Faceof Footing Heel
STRENGTH OF REINFORCED CONCRETE SECTIONSStrengthRebarLoadd
STRENGTH OF REINFORCED CONCRETE SECTIONS Location of Strength Rebarrelative to compressive face ofconcrete (d) “d” is measured from the centerof strength steel to thecompression face of the concrete “clear cover” ismeasured from thetension face of theconcrete to the surfaceof the “strength” steelClearCoverd
STRENGTH OF REINFORCED CONCRETE SECTIONS Location of Strength Rebar relative tocompressive face of concrete (d)The project calls for clear cover of 2 inches and thestrength steel is installed with a clear cover of 3 inches:Example: 10” thick wall3500 psi concrete#5@103” clear rather than the designed 2” clearBENDING STRENGTH OF THE SECTION HAS BEENREDUCED BY ABOUT 15%SHEAR STRENGTH AT WALL BASE HAS BEEN REDUCEDBY ABOUT 14%
SUMMARYSTRENGTH OF REINFORCED CONCRETE SECTIONS 28 day compressive strength of concrete (f’c)3,500 or 4,000 psi minimum Grade of Rebar (fy)Usually Grade 60 (60,000 psi yield strength) Amount of rebar (As)(size and spacing) Location of Rebar relative to compressive face ofconcrete (d)
New 8 Ft and 10 Ft Fixed Based (Cantilevered) walldesigns: now posted on the Engineering pages of the Wisconsin NRCS Website 8-ft walls x 10 inches thick 8-ft walls x 12 inches thick 10-ft walls x 12 inches thick Also, new joint drawings posted Slab to slab joints Wall to footing joints Wall to wall ail/wi/technical/engineering/?cid nrcs142p2 025429
Questions / Comments?Contact Info: mike.oshea@wi.usda.gov
STRENGTH OF REINFORCED CONCRETE SECTIONS What Determines the Strength of a Reinforced Concrete Section 28 day compressive strength of concrete (f’ c) 3,500 or 4,000 psi minimum Grade of Rebar (f. y) Usually Grade 60 (60,000 psi yield strength) Amount of rebar (A. s) (size and spacing) Location of Rebar relative to compressive .
reinforced segmental retaining wall (front GRS wall). The centerline of the reinforced concrete abutment wall and the edge of the footing are located 3.1 and 1.35 m, respec-tively, from the facing of the front GRS wall. The reinforced concrete abutment wall and two reinforced concrete wing walls (Figures 2 and 3) rest on the spread footing,
vary the overall capacity of the reinforced concrete and as well as the type of interaction it experiences whether for it to be either over reinforced or under reinforced. 2.2.2.1 Under Reinforced Fig. 3. Under Reinforced Case Figure 3.2 shows the process in determining if the concrete beam is under reinforced. The
reinforced concrete for pavement applications. However, Merta et al., (2011) studied wheat straw reinforced concrete for building material applications. They concluded that there is an increase (i.e. 2%) in fracture energy of wheat straw reinforced concrete. Thus, wheat straw reinforced concrete needs to be investigated for rigid pavements.
REINFORCED CONCRETE WALL SYSTEMS G.L. PEZZOLA1, L.K. STEWART1, & G. HEGEMIER2 . large reinforced concrete walls subjected to blast-like loadings. The experimental program utilized . a reinforced concrete specimen of dimensions 1.2 m (48 in) wide, 4.3 m (171 in) tall and 0.3 m (12 in) thick. The width and thickness of the specimen were near .
Recommended Practice for Glass Fiber Reinforced Concrete Panels - Fourth Edition, 2001. Manual for Quality Control for Plants and Production of Glass Fiber Reinforced Concrete Products, 1991. ACI 549.2R-04 Thin Reinforced Cementitious Products. Report by ACI Committee 549 ACI 549.XR. Glass Fiber Reinforced Concrete premix. Report by ACI .
experimental flexural behavior of concrete beams reinforced with glass fiber reinforced polymers bars" is done. D.Modeling . ANSYS Workbench 16.1 is used to model the concrete beams and 28 different models are considered. Concrete beams reinforced with reinforced with steel bars of circular cross
Concrete Beams 9 Lecture 21 Elements of Architectural Structures ARCH 614 S2007abn Reinforced Concrete - stress/strain Concrete Beams 10 Lecture 21 Elements of Architectural Structures ARCH 614 S2007abn Reinforced Concrete Analysis for stress calculations steel is transformed to concrete concrete is in compression above n.a. and
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