z) is to be calculated. The value n is defined as the length of the loaded area (y) divided by the depth (z). The chart is entered with the value of n and upon intersecting the desired m curve, the influence value (I) is then obtained from the vertical axis. As indicated in Fig. 6.16, vertical stress increase ( z) is then calculated as the loaded area pressure (qo) times the influence value (I). Figure 6.16 can also be used to determine the vertical stress increase ( z) below the center of a rectangular loaded area. In this case, the rectangular loaded area would be divided into four parts and then Fig. 6.16 would be used to find the stress increase below the corner of one of the parts. By multiplying this stress by 4 (i.e., 4 parts), the vertical stress increase ( z) below the center of the total loaded area is obtained. This type of analysis is possible because of the principle of superposition for elastic materials. To find the vertical stress increase ( z) outside the loaded area, additional rectangular areas can be added and subtracted as needed in order to model the loading

Whether we use a brick gauge or a tape measure and pencil to mark the brick, always aim for accuracy. This will make producing a quality piece of brickwork a much easier task. Many bricks have good compressive strength but are brittle and shatter easily. To improve the chances of success in cutting, therefore, its good practice to place the brick to be cut on a small mound of sand which will act as a cushion. Alternatives such as sacking or old carpet could also be used. Make sure the whole surface area of whichever face is on the cushion is supported. Lets look at the process. STEP 2 Mark the position of the cut on the face, the opposite side and the bed of the brick with a pencil. STEP 3 Place the brick with the face uppermost. Placing the blade of the bolster slightly on the waste side of the pencil mark, strike it lightly but firmly with the club hammer. STEP 4 Now do the same on the STEP 5 Turn the brick so that the face is opposite side of the brick. uppermost again and strike the last blow. If the strength of the blow is adjusted correctly, this should complete the operation (remember experience counts).

Clay brick High-absorption, per 4-in wythe Medium-absorption, per 4-in wythe Low-absorption, per 4-in wythe Sand-lime brick, per 4-in wythe Concrete brick 4-in, with heavy aggregate 4-in, with light aggregate Concrete block, hollow 8-in, with heavy aggregate lb/ft2 Floor Finishes lb/ft2 Asphalt block, 2-in 24 Cement, 1-in 12 Ceramic or quarry tile, 1-in 12 Hardwood flooring, 7/8-in 4 Plywood subflooring, 1/2-in 1.5 Resilient flooring, such as asphalt tile and linoleum 2 Slate, 1-in 15 Softwood subflooring, per in of thickness 3 Terrazzo, 1-in 13 Wood block, 3-in 4 8-in, with light aggregate 12-in, with heavy aggregate 12-in, with light aggregate Clay tile, loadbearing 4-in 8-in 12-in Clay tile, nonloadbearing 2-in 4-in 8-in Furring tile Wood joists, double wood floor, joist size lb/ft2 12-in spacing 9 16-in spacing 9 11/2-in 2-in Glass block, 4-in Gypsum block, hollow 2-in 4-in 6-in 8 Concrete Slabs lb/ft2 Stone aggregate, reinforced, per in of thickness 12.5 Slag, reinforced, per in of thickness 11.5 Lightweight aggregate, reinforced, per in of thickness 6 to 10 TABLE 5.1 Minimum Design Dead Loads (Continued )