Volume 4, Issue 1 (January 2007)
Deflection Criteria for Masonry Beams
This paper examines issues related to deflection criteria for masonry beams. Masonry walls supported by beams and lintels act compositely with the beam. As the height of the masonry wall increases, the behavior becomes more like that of a tied arch, with the masonry in compression and the beam acting as the tension tie. Deflection limits are only needed so that sufficient stiffness is provided during construction to prevent serviceability problems, with the suggested limit being I/600. Several methods for determining the deflection of reinforced masonry beams are examined, and a method for the effective moment of inertia of cracked reinforced sections is recommended. Beams and lintels that exceed this deflection do not necessarily have to be increased in size, but rather shores could be used during construction. Masonry beams and lintels with I/d≤8 should not be controlled by deflections. Therefore, it is recommended that the code not require these members to be checked for deflections.