The availability of mechanical properties masonry materials for structural design

Multi-storey low rise buildings in earthquake areas generally use brick masonry, lightweight brick, and concrete block as wall material. One of the structures of the building is designed as an infill wall structures. The behaviour of the structures is influenced by the infill wall material either its size or mechanical properties. From several studies, it can be stated that the presence of this infill wall can increase the strength and stiffness of a structure when compared to an open frame. RDP can increase its strength in resisting base shear forces due to earthquake and reduce the amount of displacement caused by lateral loads. This is also can be seen in the masonry beams with the reinforcing steel bars.

Infill frame material is very diverse, whether its size or mechanical properties such as compressive strength, shear strength, flexural strength, and modulus of elasticity. This mechanical property is not yet available in the Indonesian National Standard (SNI) or Indonesian reference books. However, these properties are available in foreign language references.

From research conducted using local Balinese materials, it was found that the dimensions of the bricks varied, the compressive strength was low, and water absorption was quite high. The compressive stress of the brick was high compared to concrete block and lightweight brick. The highest compressive strength was masonry made of red bricks compared to light bricks and brick. The compressive strength of a masonry loaded in its perpendicular direction was higher than those laid in the parallel direction.

The compressive strength and modulus of elasticity of the masonry can be predicted using equations available from references. From the test results, compressive strength and modulus of elasticity obtained were far different from the predicted ones. More researches are needed to gain better test results.