Acceptance Criteria for Special Unbonded Post-Tensioned Precast Structural Walls Based on Validation Testing and Commentary
|Publication Date:||1 January 2007|
This document defines minimum acceptance criteria for unbonded post-tensioned precast structural walls, including coupled unbonded post-tensioned precast structural walls, designed for regions of high seismic risk or for structures assigned to high seismic performance or design categories, where acceptance is based on experimental evidence and analysis.
This document is applicable to unbonded post-tensioned precast structural walls, coupled or uncoupled, with height-to-length ratios, hw/lw, equal to or greater than 0.5. This document is applicable to either prequalifying unbonded post-tensioned precast structural walls for a specific structure or prequalifying an unbonded posttensioned precast wall type for construction in general. This document applies to walls that are effectively continuous from the base of the structure to top of wall and are designed to have a single critical section for flexure and axial loads.
The walls of the prototype structure shall be permitted to be several panels long and several panels high, to be constructed from subpanels, and to be either coupled or uncoupled. Coupling elements shall be permitted to be devices or beams connecting adjacent vertical boundaries of the unbonded post-tensioned precast walls.
Unbonded post-tensioned precast structural walls shall be deemed to have a strength and toughness that is adequate to comply with 188.8.131.52 of ACI 318, and the corresponding unbonded post-tensioned precast structural walls of the prototype structure shall be deemed acceptable when all of the conditions in Sections 184.108.40.206 through 220.127.116.11 are satisfied.
The prototype structure satisfies all applicable requirements of this document and of ACI 318 except 21.7.
Tests on wall modules satisfy the conditions in Chapters 3 and 7.
The prototype structure is designed using the design procedure substantiated by the testing program.
The prototype structure is:
(1) Analyzed using stiffness properties consistent with those validated as prescribed in Section 5.10;
(2) Demonstrated through analysis to have design displacements for all walls equal to or less than two thirds of the displacement associated with the drift angles to which the appropriate modules have been tested in accordance with Section 5.4; and
(3) Shown to have factored engineering design values for all walls less than the nominal engineering design values used for the test modules in accordance with Section 4.2.
The structure as a whole, based on the results of the tests of Section 18.104.22.168 and analysis, is demonstrated to have the required global toughness.