3501-wood-lab - CGN3501 Civil Engineering Material Lab...

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CGN3501 Civil Engineering Material Lab Testing of Small Clear Timber Specimens Laboratory Exercise #3 Testing of Small Clear Timber Specimens PURPOSE: This lab is concerned with the determination of strength properties of small clear specimens of timber. Due to the wide variation of species, climate, growth cycles and other parameters, the testing of small clear timber specimens is very important. The laboratory procedures are governed by ASTM D 143. The following tests shall be performed: 1. Static Bending. 2. Compression Perpendicular to the Grain. 3. Compression Parallel to the Grain. 4. Shear Parallel to Grain. These tests are chosen because of their similarity to actual loadings experienced in timber construction. The compression perpendicular to the grain is similar to shear on a beam at its support while compression parallel to the grain is similar to column loading. Static bending is similar to the flexural stress experienced in a beam. Shear parallel to the grain occurs in flexural members. It is important to remember that these specimens are of clear timber, generally void of irregularities such as knots, checks and other. In actual timer design and construction, special care must be taken to avoid such irregularities in position where could have detrimental effects on the structure (e.g. a knot located on the tensile side of a beam in flexure). Lab Report: The lab report should include the following: 1) All the data sheets and summary table. 2) All the graphs called for. 3) Discussion on the parameters which affect the test result. 4) Conclusion (what has been learned from this lab?) Special Note on Graphing: Is after completing a graph, it is found that the data plotted does not appear to go through the origin; the graph should be shifted along the strain axis such that it does. This is done to correct errors in the testing since the initial loading may result in compression on the wood fibers directly under the loading. University of Florida – Department of Civil and Coastal Engineering 1
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CGN3501 Civil Engineering Material Lab Testing of Small Clear Timber Specimens Static Bending Testing Procedure: 1) Measure the specimen to obtain section properties. Approximate length of 30 inches. 2) Drive three nails into side of the specimen along its centerline, one over each support and one below the point of loading. The test will use center- point loading and a span of 28 inches.
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3501-wood-lab - CGN3501 Civil Engineering Material Lab...

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