At least two No. 5 bars should be placed around all window and door openings. The bars should extend at least 24 in beyond the corners of openings. Design for Eccentric Loads. Bearing walls with bending moments sufficient to cause tensile stress must be designed as columns for combined flexure and axial load, including slenderness effects if applicable. Minimum reinforcement areas and maximum bar spacings are the same as for walls designed by the empirical method. Lateral ties, as for columns, are required for compression reinforcement and where the vertical bar area exceeds 0.01 times the gross horizontal concrete area of the wall. (For column capacity, see Art. 9.82.) Under the preceding provisions, a thin, wall-like (rectangular) column with a steel ratio less than 0.01 will have a greater carrying capacity if the bars are detailed as for walls. The reasons for this are: The effective depth is increased by omission of ties outside the vertical bars and by the smaller cover (as small as 3/4 in) permitted for vertical bars in walls. Furthermore, if the moment is low (eccentricity less than one-sixth the wall thickness), so that the wall capacity is determined by Eq. (9.82), the capacity will be larger than that computed for a column, except where the column is part of a frame braced against sidesway. If slenderness effects need to be considered, slender walls must comply with the slenderness requirements for columns (Art. 9.86). For slender precast concrete wall panels, where the panels are restrained at the top, an alternative design procedure can be used. The alternative approach was introduced into Chapter 14 of the ACI 318-99 Building Code. Complying with the provisions in the alternative procedure is deemed to satisfy the Codes slenderness requirements for columns. Nonbearing reinforced-concrete walls, frequently classified as panels, partitions, or cross walls, may be precast or cast in place. Panels serving merely as exterior cladding, when precast, are usually attached to the columns or floors of a frame, supported on grade beams, or supported by and spanning between footings, serving as both grade beams and walls. Cast-in-place cross walls are most common in substructures. Less often, cast-in-place panels may be supported on grade beams and attached to the frame. In most of these applications for nonbearing walls, stresses are low and alternative materials, such as unreinforced masonry, when supported by beams above grade, or panels of other materials, can be used. Consequently, unless esthetic requirements dictate reinforced concrete, low-stressed panels of reinforced concrete must be designed for maximum economy. Minimum thickness, minimum reinforcement, full benefits of standardization for mass-production techniques, and design for double function as both wall and deep beam must be achieved. Thickness of nonbearing walls of reinforced concrete should be at least onethirtieth the distance between supports, but not less than 4 in. The ACI 318 Building Code, however, permits waiving all minimum arbitrary requirements for thickness and reinforcement where structural analysis indicates adequate strength and stability. Where support is provided, as for a panel above grade on a grade beam, connections to columns may be detailed to permit shrinkage. Friction between base of panel and the beam can be reduced by an asphalt coating and omission of dowels. These provisions will permit elimination or reduction of horizontal shrinkage reinforcement. Vertical reinforcement is seldom required, except as needed for spacing the horizontal bars. If a nonbearing wall is cast in place, reinforcement can be nearly eliminated except at edges. If the wall is precast, handling stresses will often control. Multiple pickup points with rigid-beam pickups will reduce such stresses. Vacuum pad pickups can eliminate nearly all lifting stresses. Where deep-beam behavior or wind loads cause stresses exceeding those permitted on plain concrete, the ACI 318 Building Code permits reduction of minimum tension-reinforcement [As
200bd/y (Art. 9.46)] if reinforcement furnished is onethird greater than that required by analysis. (For deep-beam design, see Art. 9.88.) Under the ACI 318 Building Code, cantilever retaining walls are designed as slabs. Specific Code requirements are not given for cantilever walls, but when axial load becomes near zero, the Code requirements for flexure apply. FIGURE 9.38 Factored loads and critical sections for design of cantilever retaining

The art of craft building has not been destroyed; however, the cost of providing them has become an issue. Today it is more difficult to find a builder with the skill and experience of how to provide for a client group who have their own ideas as to what they should incorporate in their homes. Today if one visits a technical college providing craft training, one will find a situation where the amount of training, depth and complexity have declined and this is a sign of financial pressure of building in general. One thing is for sure though, while the desire to recreate stylist features from the past continues, the need for specialist crafts people will continue. Unlike some building crafts, the bricklayer does not need to own a large amount of tools in order to carry a range of tasks; considerations on the other hand lies more toward the quality of tool instead. Other factors come into play when you assess just how much bricklaying is to be carried out over a period of time; why buy a set of top quality golf clubs if one day a week is your target? While tools need to robust, if a single project is to be undertaken it may be prudent to purchase a middle of the road items instead of a professional outfit. Its similar to photography in a way. You can take a good picture on a medium priced camera but if you planned to take it up full time then a top of the range model would be a better bet. It must be said that cheap tools are not only an unsound financial investment they can be unsafe. Blades on trowels can become unstable if fully loaded and sprit levels can offer false readings with only the smallest knock. When working with any tool you should remember that each tool should only be used for the job in hand; the reasons being that due to the uncertainly of there durability and reliability you may be faced with safety quality issue. Its true to say that you get what you pay for when it comes to any tool but it can help build your confidence if you know you are using industry standard equipment. Taking trip to your local DIY / hardware store or builder merchants will give you a selection to pick from. One thing to remember is that once you have used them its extremely difficult to return for a refund if they dont fit the bill. So lets take a look at the typical tools to be found in a bricklayer tool kit!

Dry Spacing bricks without mortar to sort out potential problems with the bond Perp joints Small vertical joints which join two bricks together Setting out dry: notice there is no mortar between the bricks The main purpose for bonding bricks is for strength. In the workshop, ask your tutor to mark wall dimensions on the floor that are not whole brick sizes. Work with someone else to decide which method you will use to establish a good bonding arrangement. The most common bond is Stretcher bond. The name refers to the long face of the brick, which is called the stretcher face, see the illustration on the previous page. In Stretcher bond the bricks are arranged with an overlap the width of a brick (102.5mm). This means that the perp joints are exactly halfway along the face of the stretchers in the course below, so Stretcher bond is often called half- bond. Since the width of the wall is almost the same as half a brick, we refer to Stretcher bond as half-brick walling.