by Albert E. Brumley For Craig Courtney arranged for TTBB ...
GUIDELINES FOR THE EVALUATION OF FOUNDATION...
Transcript of GUIDELINES FOR THE EVALUATION OF FOUNDATION...
Lowell Brumley, TSG Consultants Inc. 1
GUIDELINES FOR THE EVALUATION OFFOUNDATION MOVEMENT FOR RESIDENTIAL
AND OTHER LOW-RISE BUILDINGS
Document no: FPA-SC-13
Developed by: FPA Structural Committee
Committee chairs: Main Committee - Ron Kelm, P.E.Subcommittee - Lowell Brumley, P.E.
Subcommittee: Dan Jaggers, Michael Skoller, Mari Mes,Michael Gray, John Clark, Nicole Wylie,Dick Peverley, Denis Hanys, Ron Kelm
Presented by: Lowell Brumley, P.E., TSG Consultants Inc.
Presented to : Foundation Performance Association
Presented on: 8 August 2007
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Why was it written?
…a brief history…
FPA-SC-13 Presentation 8 Aug 07
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Who can use this document?
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Levels of Investigation• Per ASCE Texas Section’s
Guidelines for the Evaluationand Repair of ResidentialFoundations
• Levels A, B and C
Data Acquisition & Presentation
Data Evaluation
Allowable Criteria forFoundation Movement
FPA-SC-13 Presentation 8 Aug 07
Document Summary
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Level A Investigation• Interview the occupant/
owner/client for history ofproperty and performance ofstructure
• Review client supplieddocuments
• Make visual observationsduring walk-through
• Observe factors influencingthe performance of thefoundation
• Provide written report, ifrequested by client
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Level B Investigation• All of Level A, with written
report
• Determine relative foundationelevations in sufficient detailto represent the shape of thefoundation adequately
• Include drawing showingrelative elevations
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Level C Investigation• All of Levels A and B
• Additional services, testingand related reports deemedappropriate by the Engineer.May include soil test,plumbing test, material test,etc.
• More detailed written report,which may include scaleddrawings, tree survey, photos,distress survey.
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Levels of InvestigationData Acquisition &
Presentation
Data Evaluation
Allowable Criteria forFoundation Movement
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Document Summary
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FPA-SC-13 Presentation 8 Aug 07
GARAGECONC RETE
PATIOBRICK
LIVINGWOOD
FOYERWOOD
DININGWOOD
KITCHENWOOD
BREAKFASTWOOD
PDRWOOD
CL
UP
PORCHBRICK
PANTRY
REF
0.0
-4.9 -5
.7
-7.3
-3.1
-4.3
-5.7
-3.1
-3.7
-2.6
-2.3
-3.2
-2.8
-2.5
-1.9
-2.2 -2
.8
-0.3
-1.4 -2
.1
0.1
-0.7
-1.4
-0.9
-1.6
-2.0
-2.5
-3.1
-2.5
-3.2
-3.9
-3.6-2
.2
-2.2
-0.6
-1.2
-3.6
-7.2
-8.3
-9.6
-7.8
-9.0
-9.8
-8.4
-9.1
-10.
0
0.0
-0.7
-0.1
-0.6
-1.1
-0.9
-1.4 Zip Level
Digital Leveling SystemsElectronic Water Level
Data Acquisition and Presentation
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Levels of Investigation
Data Acquisition &Presentation
Data Evaluation
Allowable Criteria forFoundation Movement
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Document Summary
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Data EvaluationComparing elevationsover a two-year periodusing Contours
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Levels of Investigation
Data Acquisition &Presentation
Data Evaluation
Allowable Criteria forFoundation Movement
FPA-SC-13 Presentation 8 Aug 07
Document Summary
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Important Definitions:
Deflection is the distorted shape of a structuralelement due to bending. As shown below,Deflection is the vertical distance betweenany point 2 on the surface and a line L13 thatconnects two end points 1 and 3 on thatsurface.
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Important Definitions:
Deflection Ratio is defined as the Deflectiondivided by the horizontal distance overwhich the Deflection occurs, and is used ascriteria of acceptance when evaluatingFoundation Movement.
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FPA-SC-13 Presentation 8 Aug 07
Important Definitions:
Deflection Limit is defined as the EffectiveLength divided by a number, and is used ascriteria of acceptance when evaluatingFoundation Movement. Deflection Limit isthe length times the maximum DeflectionRatio.
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Important Definitions:
Tilt is defined as a planar rotation,measured over the length or width ofthe Foundation.
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Important Definitions:
Effective Length is the length of a straight line(L) drawn along a minimum of three pointsin the plan view for which the Elevationsare known, multiplied by the "k" factor(i.e., kL).
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Deflection calcs are easy… just solve thefollowing equation:
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The Real Equations
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!
Deflection = " = Y2# [Y1+ (L12
L)(Y3 #Y1)]
Deflection Ratio = L
r where r =
Linches
" inches
Tilt =YB #YA
LAB
x 100%
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Allowable Criteria for Foundation Movement
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The “ ” factor
!
k =length2 +width2
length
Deflection Limit = kL / 360
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FPA-SC-13 Presentation 8 Aug 07
The “ ” factor
!
k =length2 +width2
lengthDeflection Limit = kL / 360
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Allowable Criteria for Foundation Movement
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Determining Principal Axis’ Length and Width
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Example A
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Ex. L L12 Y1 Y2 Y3 ! (inches)
A 50’ 10’ 0” 1.4” -1.2” 1.64 L/366
!
Deflection = " = Y2# [Y1+ (L12
L)(Y3 #Y1)] = 1.4 # [0+ (
10
50)(-1.2# 0)] =1.64
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Example B
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Ex. L L12 Y1 Y2 Y3 ! (inches)
B 60’ 30’ 1.4” -1.2” 1.0” -2.4 L/300
!
Deflection = " = Y2# [Y1+ (L12
L)(Y3 #Y1)] = -1.2 # [1.4+ (
30
60)(1.0#1.4)] = -2.4
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Example C
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Ex. L L12 Y1 Y2 Y3 ! (inches)
C 30’ 20’ -1.2” -0.5” 1.0” -0.78 L/470
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Tilt
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Deflection Limit:
L / 240?
L / 360?
L / 480?
Why did we choose L/360?
Allowable Criteria for Foundation Movement
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Determining AllowableCriteria for Foundation
Movement
Calculation Spreadsheet
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Deflection Limit: kL / 360
Tilt: 1% maximum
In Summary…
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QUESTIONS?
Download “Guidelines for the Evaluation of Foundation Movementfor Residential and Other Low-Rise Buildings” at:
http://www.foundationperformance.org/committee_papers.cfm