Table 1. Accuracy Requirements for Timber Piles 

 [Nomenclature at end of table.] 



Structural Evaluation 

 Criteria 



Type and Extent of 

 Deterioration 



Field Data 



Required 



Accuracy 



Requirement 



(±%) 



Parameter 



Range 



A. Material Strength 



Internal Damage 









f a = P/A 



1. Magnitude - cross- 

 sectional area: 









or 



V A o " °- 5 



A R 



50-150 in. 2 



20 





A R /A < 0.5 



A R 



0- 75 in. 2 



25 



B. Instability 

 Short Column: 



2. Length/location 



L d> H d 



>l-2 ft 



20 



f c - 3 [l/r'J 



External Damage 



1. Confined damage 









applied where f < (2/3)F c 



Long Column: 



TT E T 



f = — 



C («7r) 2 



region: 

 L d /L < 0.2 

 V A > °' 5 



L d 

 A R 

 d R 



1-8 ft 



50-150 in. 2 



8-14 in. 



20 

 20 

 10 



V A < °' 5 

 Location 



A R 

 H d 



0-75 in. 2 

 >l-2 ft 



25 

 20 





2. Extended damage 







- 





region: 











L d /L > 0.2 



L d 



>8-10 ft 



2 





V A o > °- 5 



A R 



50-150 in. 2 



14 







d R 



8-14 in. 



7 





A R /A < 0.5 



A R 



0-75 in. 2 



25 





Location 



H d 



>l-2 ft 



20 



A = cross-sectional area 

 A n = original cross-sectional area 



*R 



R 



remaining cross-sectional area 

 diameter of remaining cross-sectional 



area 



f = axial stress 

 a 



f = critical stress for a column 

 c 



H . = location of damaged section along pile 

 length, distance from pile cap to seabed 

 or to midpoint of damaged section 



L = total length of structural element 

 L. = length of damaged section 

 Jl = unsupported length 

 P = axial load 



F = critical buckling stress 



r = radius of gyration 

 E T = modulus of elasticity 



