It is recommended that the procedures stated in various codes of 

 practice be adapted. For compression members the effect of reinforce- 

 ment is permitted to contribute to the ultimate capacity of the member 

 as long as the reinforcement is tied against lateral movement as in a 

 column. If the compression reinforcement is not tied, then the member 

 is designed as unreinforced concrete. 



Out-of-Roundness . The design chart in Figure 3 is based on 

 empirical data and, therefore, contains an inherent out-of-roundness 

 allowance. This allowance for thick-walled cylinders is given in Table 

 1. The thin-walled cylinder test specimens were studied in detail for 

 out-of-roundness, and Table B-2 in Appendix B (pg 51) presents a 

 digest of their out-of-roundness. A structure having geometric toler- 

 ances equal to or less than the test specimens will be safely designed 

 using Figure 3. Conventional construction practices should encounter 

 few problems in matching the geometric tolerances of the test speci- 

 mens. 



It is recommended that, once a structure is sized-out by Figure 3 

 and meets its other design requirements, a detailed finite element anal- 

 ysis be conducted. The analysis should assume a realistic out-of-round 

 geometry and model the inelastic behavior of concrete materials. 



SUMMARY 



The updated design guides represent some significant changes 

 compared to the guides presented in Reference 8. The design approach 

 for thick-walled cylinders was made comparable to that for thick-walled 

 spheres by using an average wall stress equation with an empirical 

 strength factor, k . Thin- walled cylinders used the same design 

 approach as described in Reference 8; however, new experimental 

 results from 15 relatively large-scale specimens permitted a more accu- 

 rate development of an empirical plasticity reduction factor, O- 



22 



