4. Slightly Organic Soils. These soils typically have less than 5% organic matter. Per the Unified Soil Classification System, they have a ratio of liquid limit (ovendried soil) divided by liquid limit (not dried soil) that is greater than 0.75. Often a modifier, such as slightly organic soil, is used to indicate the presence of organic matter. Also included in Table 6.10 is the typical range of laboratory test results for the four major divisions of organic material. Note in Table 6.10 that the water content (w) increases and the total unit weight (t) decreases as the organic content increases. The specific gravity (G) includes the organic matter, hence the low values for highly organic material. The compression index (Cc) is discussed in Art. 6.5.6. Other Descriptive Terminology. In addition to the classification of a soil, other items should also be included in the field or laboratory description of a soil, such as: 1. Soil Color. Usually the standard primary color (red, orange, yellow, etc.) of the

The aim is to produce clean sharp edges especially on the face side of the cut brick. This will ensure a good appearance in the finished wall. If there are rough projections or edges, then a scutch hammer can be used to trim the cut brick and to make precise adjustments. The other cutting tool mentioned in our previous list is a brick hammer. This can also be used for trimming bricks but it is less precise and is usually used to quickly produce rougher cuts where appearance is not so important. High standards in selecting, moving, cutting or laying bricks depends on skill, care and attention and the use of the correct tools and techniques. This is no less true with the other important material used by the bricklayer: mortar. Whilst it is usually the case that mortar is mixed and brought to the bricklayer by semi-skilled operatives, it is the bricklayers responsibility to make sure that the material is fit for purpose and is used in accordance with the specification. Mortar is the material we use to bed and joint the bricks together. It is mainly composed of well graded sand (either pit sand or sea-dredged sand) and Ordinary Portland Cement (often referred to as OPC) mixed to a specified ratio. There are other types of cement which you will learn about later in your studies. Mixing these two component materials together with water will produce a mix that is difficult to use, so a plasticiser is added to improve workability. This usually comes in the form of a chemical additive that traps tiny bubbles of air in the mix, which allows the grains of sand to move over each other more freely.

live load Roof beams: Industrial l /180 l /120 Commercial and industrial: Without plaster ceiling l /240 l /180 With plaster ceiling l /360 l /240 Floor beams: Ordinary usage* l /360 l /240 Highway bridge stringers l /200 to l /300 Railway bridge stringers l /300 to l /400 * Ordinary usage classification is intended for construction in which walking comfort, minimized plaster cracking, and elimination of objectionable springiness are of prime importance. For special uses, such as beams supporting vibrating machinery or carrying moving loads, more severe limitations may be required. Deflection of wood beams is calculated by conventional elastic theory. For example, for a uniformly loaded, simple-span beam, the maximum deflection is computed from 
5wL4 /384EI (10.19) where w
the uniform load L
span E
modulus of elasticity I
moment of inertia Deflection should not exceed limitations specified in the local building code nor industry-recommended limitations. (See, for example, K. F. Faherty and T. G. Williamson, Wood Engineering and Construction Handbook, McGraw-Hill Publishing Company, New York.) Deflections also should be evaluated with respect to other considerations, such as possibility of binding of doors or cracking of partitions