Copyright Goodheart-Willcox Co., Inc. Chapter 14 Wall Systems 289 Grouting techniques vary in different areas of the country. The International Building Code speci- fies that grouted masonry is to be constructed so all elements of grouted masonry act together as a struc- tural element. Grout materials and water content should be controlled and mixed thoroughly to provide sufficient fluidity for placement without separa- tion of the components. Reinforcement should be clean, positioned properly, and solidly embedded in the grout. Code Note Grouting The International Building Code Uniform Building Code specifies that prior to grouting, all spaces to be filled with grout should not contain mortar projections greater than 1/4″ (6.4 mm), mortar droppings, or foreign material. Spaces to be grouted should not contain voids. The grouting of a section of wall should be completed in one day with no interruptions greater than one hour. Between grout pours, a horizontal construction joint should be formed by stopping all wythes at the same elevation. The grout should stop at least 1 1/2″ (38 mm) below a mortar joint, except at the top of the wall. Where bond beams occur, the grout pour should be stopped a minimum of 1/2″ (12.7 mm) below the top of the masonry. Reinforced masonry walls should be reinforced with an area of steel not less than 0.002 times the cross-sectional area of the wall. Not more than two- thirds of this area may be used in either direction. Maximum spacing of principal reinforcement should not exceed 48″. Horizontal reinforcement should be placed in the top of footings, the bottom and top of wall openings, roof and floor levels, and at the top of parapet walls. The primary use of steel reinforcement is in vertical members (such as columns and walls), lintels, and bond beams. Typical methods of rein- forcing concrete masonry are shown in Figure 14-24. Retaining Walls Reinforced masonry is ideal for the construction of retaining walls that must withstand lateral earth pressures. By adding reinforcement, the mass can be greatly reduced and the strength maintained. Two common types of retaining walls are the gravity and cantilever designs. A gravity-type retaining wall depends primarily on its own weight to hold back the earth pressure. See Figure 14-25. A cantilever- type retaining wall uses the weight of the soil together with its own strength to get the same results. See Figure 14-26. For walls over 3′ in height, the canti- lever-type retaining wall provides the best solution. Goodheart-Willcox Publisher Figure 14-24. Typical locations of reinforcement for concrete block masonry construction. Goodheart-Willcox Publisher Figure 14-25. Gravity-type retaining wall with specifica- tions. The width of the base must be at least 1/2 to 3/4 of the wall height. This is expressed in the drawings as “0.7H” or “0.7 of the height.” 6" minimum Porous backfill Weep holes 12' 0" O.C. 4" 4" 8" minimum H = 4' 0" 0.7 H Varies