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INSTRUCTION NO 1 OF 1982CQP~TRUC~ION IN LOAD BEARING WALLS0.1 Load bearing masonry walls/brick work is not new but suitably designedload bearing walls/br~ckwork is of comparatively recent origin. The first IndianStandard Code was issued in 196 1 and su bseq uen tl y revised in 1 %9 and I 980, :IS1905 of 1980 'Code of Pract ice for structural safety of buildings Masoniy walls'. Inthe past twenty years there has been emergence of modern struct uraI masonry formu1 tistoreyed construction in many countries. The development has beenbased on application of structural engineerin principles to design of masonrystructures, thus overcoming the limitations of ''K ule of thum by procedures./0.2 Basic advantage of masonry construction lies in the fact that in loadbearing construction masonry performs a variety of functions viz; sup flingloads, sub-dividing space, providing thermal and accoudic insulation, i% andweather protection etc., which in framed buildings have to be provided forseparately.0.3 In Western countries 12 to 20 storeyed well designed load bearingmasonry buildin s have been constructed having only 20 to, 4Ucm thick walls. PnIndia quality o f bricks manufactured are comparatively poor and maximumcrushing stren th generally is of order of 70 to 150 k cm*. In many Westerncountries bric f s of even medium quality have crus f ing strength 400 to 600kg/cm4. A few mechaniseil brick plants have since been set up at few laces in ourcountry and bricks af 150 to 250 kg/cmY strength are bein manu actured. ItkPshould now be possible in some parts of India to go in or 5 to 6 storeyedload bearing structures at costs 15 to 20 % less than RCC framed construction.I. Z The structural adequacy of masonry waIls depends upon a number offactors as under:-(a) Strength of masonry unit bricks or bIocks(b) Strength of mortar(c) Workmanship and method of bonding(d) Location of longitudinal and cross walls(e) Position and size of openings in the walls(0 Unsupported height and length of walls and slenderness ratio(g) Eccentricity in the bading(h) Combination of various loads to which walls are subjected..$; -, ,-. 8.1 These are generally of the following types:. - (a) Cornman burni cloy brickSpecifications are laid down in IS 1077of I976 'specifications for common burnt clay building bricks' (third re-