Table B-6. Ultimate Radial Displacements and Calculated Strains 



Group 



No. of 

 Specimen 



n 



ARj 



(in.) 



(in.) 



"'m 

 (in.) 



Wb 

 (in.) 



■^m 

 (Min./in.) 



Eb 

 (^in./in.) 



Strains at I'iat Spot on - 



biside Wall, 



f m ^ <^b 



(Min./in.) 



Outside Wall, 



fm + fb 

 (Min./in.) 



1 

 2 

 3 



1 

 2 

 4 



3 

 2 

 3 



0.050 

 0.057 

 0.042 



0.200 

 0.508 

 0.185 



0.043 

 0.051 

 0.052 



0.207 

 0.514 

 0.175 



1,670 

 2,040 

 2,080 



1,560 

 2,240 

 2,040 



+ 110 



-200 



-40 



+ 3,230 

 +4,280 

 +4,120 



Average 





-110 

 tension 



+ 3,880 

 compression 



ANALYTICAL RESULTS AND DISCUSSION 



Analysis Description 



A structural analysis was performed on the experimental specimens 

 using a finite element method called NONSAP-A that incorporated an 

 advanced constitutive relation subroutine for the concrete. The analy- 

 sis was conducted by Chen, Chang, and Suzuki (Ref 20) without the 

 benefit of the test results . Information on specimen geometry (includ- 

 ing the out-of- round geometry, boundary conditions, and material 

 properties) was supplied. It was desired to computationally model the 

 test specimens as realistically as possible and then determine the accu- 

 racy of the predictions . 



Constitutive Model . The constitutive model was developed in three 

 parts - elastic, plastic and fracture - for concrete under general stress 

 states . 



For elastic concrete, it was assumed that, initially, concrete is an 

 isotropic homogeneous linear elastic material and its stress-strain rela- 

 tions are described completely by two elastic constants, Poisson's ratio, 

 V, and Young's modulus, E. For the present analysis, v = 0.19 was 

 used, and E = 3.66x10^ and 4.19x10^ psi (25.2 and 28.9 GPa) were 



70 



