Wall Index (WI), also known as "wall density", is a ratio of the total cross-sectional area for all structural walls aligned in one direction of the building's floor plan and the gross floor plan area. Reconnaissance studies after past earthquakes in countries like Chile, Mexico, and China, confirmed that WI is one of the key parameters related to seismic performance of loadbearing masonry structures which influences the extent of earthquake damage. The WI requirements have been included in several international codes and guidelines. According to Eurocode 8 (EN 1998(EN :1-2005, WI can be used as a design parameter for seismic design of simple masonry buildings with regular configuration and limited height up to 5 storeys, as an alternative to a more elaborate and complex seismic analyses approaches. The required WI for a building depends on the seismic hazard for the building site, number of storeys, type of masonry (unreinforced/ reinforced/confined) and the mechanical properties of masonry (compressive/shear strength). WI can be also used for seismic assessment of existing masonry buildings in pre-and postearthquake situations, as documented by studies from Chile and Mexico. The paper will provide a comparison of the masonry design requirements from selected codes, including the 1964 and 1981 Yugoslav technical regulations for design and construction of buildings in seismic regions and Eurocode 8. A case study of a masonry residential building which was damaged in the 2010 Kraljevo earthquake (M 5.5) and evaluated using different codes is also presented in the paper.

No abstract

An experimental study is performed to evaluate the effect of melt-extract stainless steel fibres on mechanical and flexural properties of concrete. A total of seventy-two specimens are used to determine an optimum fibre dosage and mechanical properties of plain and steel fibre reinforced concrete. Twelve full-scale beam specimens are then exposed to four-point bending tests. The effect of melt-extract stainless steel fibres on flexural behaviour of beams is quantified in this testing. A beam specimen is exposed to four-point bending, after being subjected to 15000 cycles of fatigue load. Pre- and post-fatigue flexural properties of beams with melt-extract steel fibres are compared and discussed.

No abstract

No abstract