Out-of-plane lateral load resistance of slender post-tensioned masonry walls with unbonded tendons

The 2002 edition of the Masonry Standards Joint Committee (MSJC) design provisions for masonry structures includes a chapter on the design of post-tensioned masonry (PTM) walls with either bonded or unbonded tendons. Recent research indicates that the MSJC formula for moment capacity of PTM sections can be inaccurate if unbonded tendons are used. An experimental program is underway to investigate the resistance of slender PTM walls to transverse loading. Six 4.27-m (14-ft) tall walls with 810 × 100 mm (32 × 4 in.) cross-sections are being tested under monotonically increasing transverse loads. Three walls were made using clay brick, and the other three using concrete block. The walls are post-tensioned using threaded steel rods that are not restrained from lateral deflection relative to the masonry. The experimental investigation is outlined, and flexural strengths of the walls are calculated using the MSJC formulas, as well as using proposed modifications to the MSJC procedure.