| = 6.8 — Inelastic analysis | |
| == 6.8.1 General | |
| === 6.8.1.1 An inelastic analysis shall consider material nonlinearity. An inelastic first-order analysis shall satisfy equilibrium in the undeformed configuration. An inelastic second-order analysis shall satisfy equilibrium in the deformed configuration. | |
| === 6.8.1.2 An inelastic analysis procedure shall have been shown to result in calculation of strength and deformations that are in substantial agreement with results of physical tests of reinforced concrete components, subassemblages, or structural systems exhibiting response mechanisms consistent with those expected in the structure being designed. | |
| = R6.8 — Inelastic analysis | |
| == R6.8.1 General | |
| === R6.8.1.1 Material nonlinearity may be affected by multiple factors including duration of loads, shrinkage, and creep. | |
| === R6.8.1.2 Substantial agreement should be demonstrated at characteristic points on the reported response. The characteristic points selected should depend on the purpose of the analysis, the applied loads, and the response phenomena exhibited by the component, subassemblage, or structural system. For nonlinear analysis to support design under service-level loading, characteristic points should represent loads and deformations less than those corresponding to yielding of reinforcement. For nonlinear analysis to support design or assess response under design-level loading, characteristic points should represent loads and deformations less than those corresponding to yielding of reinforcement as well as points corresponding to yielding of reinforcement and onset of strength loss. Strength loss need not be represented if design loading does not extend the response into the strength-loss range. Typically, inelastic analysis to support design should employ specified material strengths and mean values of other material properties and component stiffnesses. Nonlinear response history analysis to verify the design of earthquake-resistant concrete structures should employ expected material strengths, expected material properties, and expected component stiffnesses, as specified in A.6.2. | |
| American Concrete Institute – Copyrighted © Material – www.concrete.org | |
| PART 2: LOADS & ANALYSIS 85 | |
| No further reproduction or distribution is permitted. | |
| === 6.8.1.3 Unless slenderness effects are permitted to be neglected in accordance with 6.2.5.1, an inelastic analysis shall satisfy equilibrium in the deformed configuration. It shall be permitted to calculate slenderness effects along the length of a column using 6.6.4.5. | |
| === 6.8.1.4 The cross-sectional dimensions of each member used in an analysis to calculate slenderness effects shall be within 10 percent of the specified member dimensions in construction documents or the analysis shall be repeated. | |
| === 6.8.1.5 Redistribution of moments calculated by an inelastic analysis shall not be permitted. | |
| === R6.8.1.3 Refer to R6.7.1.2. | |
| === R6.8.1.5 Section 6.6.5 allows for redistribution of moments calculated using elastic analysis to account for inelastic response of the system. Moments calculated by inelastic analysis explicitly account for inelastic response; therefore, further redistribution of moments is not appropriate. | |
| [ Lanjut Ke 6.9—Acceptability of finite element analysis ... ] | |
| | |
| | |