When a T form is used to provide needed compression area for an isolated beam, flange thickness should be at least one-half the web width, and flange width should not exceed 4 times the web width. When a T is formed by a beam cast integrally with a slab, only a portion of the slab is effective. For a symmetrical T-beam, the effective flange width should not exceed one-fourth the beam span, nor should the width of the overhang exceed 8 times the slab thickness nor one-half the clear distance to the next beam. For a beam having a flange on one side only, the effective flange width should not exceed one-twelfth the span, 6 times the slab thickness, nor one-half the clear distance to the next beam. The overhang of a T-beam should be designed to act as a cantilever. Spacing of the cantilever reinforcement should not exceed 18 in or 5 times the flange thickness. In computing the moment capacity of a T-beam, it may be treated as a singlyreinforced beam with overhanging concrete flanges (Fig. 9.15). The compression force on the web (rectangular beam) is C
0.85
b a (9.33) w cw where bw
width of web. The compression force on the overhangs is C
0.85
(b  b )h (9.34) c w where h
flange thickness and b
effective flange width of the T-beam. Forces equal in magnitude to these but opposite in direction stress the tension steel: T
A (9.35) w swy

Procedure Type of sample Applications Limitations Rotary coring of soil or soft rock Outer tube with teeth rotated; soil protected and held stationary in inner tube; cuttings flushed upward by drill fluid (examples: Denison, Pitcher, and Acker samplers) Relatively undisturbed sample, 50 to 200 mm (2 to 8 in) wide and 0.3 to 1.5 m (1 to 5 ft) long in liner tube In firm to stiff cohesive soils and soft but coherent rock Sample may twist in soft clays; sampling loose sand below water table is difficult; success in gravel seldom occurs Rotary coring of swelling clay, soft rock Similar to rotary coring of rock; swelling core retained by third inner plastic liner Soil cylinder 28.5 to 53.2 mm (1.1 to 2.0 in) wide and 600 to 1500 mm (24 to 60 in) long, encased in plastic tube In soils and soft rocks that swell or disintegrate rapidly in air (protected by plastic tube) Sample smaller; equipment more complex Rotary coring of rock, Outer tube with diamond bit on lower end rotated to cut annular hole in rock;

Figure 4 Insoluble white deposits on brickwork then removing it with too much acid and/or too little water. Refer to the section on mortar stains within this page for details on the correct method of cleaning with acid. When not enough water is used before and after the acid wash, the products of the reaction between the acid and the mortar can be absorbed into the face of the bricks instead of being washed off the wall. Remedy: Apply full strength Noskum to stained bricks and allow the solution to stand for four to six minutes if the reaction is not immediate. Scrub vigorously and wash off with plenty of water whilst still scrubbing. There is no guarantee that this will resolve the problem in severe cases, as scum is extremely hard to remove. Brick Cleaning and Maintenance Brick Technical Manual 36 3.6 Iron Stains Dark patches (usually yellow to deep brown in colour) of iron oxide staining can occur on the face of the brick or in the mortar joints. Iron stains are more noticeable on light coloured bricks and in the mortar joints of dark coloured bricks.