Cyclopedia of Architecture: Materials. Statics. Roof trusses. HardwareAmer. tech. soc., 1912 |
Common terms and phrases
angles Architect arrowheads beam bending bending moment bolt butts cast iron center of gravity chord column components compression compressive stress crane cross-section denote determine diameter door draw elastic limit end supports equation EXAMPLES FOR PRACTICE F₁ F₂ factor of safety feet long fibre foot-pounds force polygon forces acting formula given hardware hence hinge horizontal I-beam inertia left reaction line of action lock magnitude and direction material moment of inertia moments neutral axis number of rivets plate polygon for joint pounds per square pull purlins R₁ radius of gyration represented in Fig represents the magnitude respectively resultant roof trusses runway girder safe load sash scale section modulus shaft shearing stress shown in Fig side snow load span square foot square inch Strength of Materials stress diagram sustains Table tensile tensile stress tension three forces unit-stress vertical wind pressure wrought iron
Popular passages
Page 138 - The foregoing equations show that the rectangular component of a force along any line equals the product of the force and the cosine of the angle between the force and the line. They show also that the rectangular component of a force along its own line of action equals the force, and its rectangular component at right angles to the line of action equals zero. Examples. 1. A force of 120 pounds makes an angle of 22 degrees with the horizontal. What is the value of its component along the horizontal...
Page 105 - X 264' = 441,817.6. Hence d2 = 176.73, or d = 13.3 inches. 2. What size of cast-iron column is needed to sustain a load of 100,000 pounds with a factor of safety of 10, the length of the column being 14 feet ? We shall suppose that it has been decided to make the crosssection circular, and shall compute by Rankine's formula modified for cast-iron columns (equation 10'). The breaking load for the column would be 100,000 X 10 = 1,000,000 pounds.
Page 115 - ... coefficients of elasticity for steel and wrought iron, for different grades of those materials, are remarkably constant; but for different grades of cast iron the coefficients range from about 10,000,000 to 30,000,000 pounds per square inch. Naturally the coefficient has not the same value for the different kinds of wood; for the principal woods it ranges from 1,600,000 (for spruce) to 2,100,000 (for white oak). Formula 17 can be put in a form more convenient for use, as follows : Let P denote...
Page 12 - By working strength of a material to be used for a certain purpose is meant the highest unit-stress to which the material ought to be subjected when so used. - Each material has a working strength for tension, for compression, and for shear, and they are in general different. By factor of safety is meant the ratio of the ultimate strength of a material to its working stress or strength. Thus, if Su denotes ultimate strength, Sw denotes working stress or strength, and f denotes factor of safety, then...
Page 52 - handbooks" there can be found tables of moments of inertia of all the cross-sections of the kinds and sizes of rolled shapes made. The inertia-axes in those tables are always taken through the center of gravity of the section, and usually parallel to some edge of the section. Sometimes it is necessary to compute the moment of inertia of a "rolled section...
Page 17 - Bending test, 180 degrees flat on itself, without fracture on outside of bent portion. 10. Soft Steel. — Ultimate strength, 52,000 to 62,000 pounds per square inch. Elastic limit, not less than one-half the ultimate strength. Elongation, 25 per cent.
Page 55 - The moment of inertia of an area with respect to any axis equals the moment of inertia with respect to a parallel axis through the center of gravity, plus the product of the area and the square of the distance between the axes.
Page 6 - Fig. 1. 1,000 pounds, or -| ton. Notice that this value has nothing to do with the size of the cross-section on which the stress acts. 3. Kinds of Stress, (a) When the forces acting on a body (as a rope or rod) are such that they tend to tear it, the stress at any cross-section is called a tension or a tensile stress. The stresses P and Q, of Fig. 1, are tensile stresses. Stretched ropes, loaded "tie rods" of roofs and bridges, etc., are under tensile stress.
Page 335 - REVIEW QUESTIONS. PRACTICAL TEST QUESTIONS. In the foregoing sections of this Cyclopedia numerous illustrative examples are worked out in detail in order to show the application of the various methods and principles. Accompanying these are examples for practice which will aid the reader in fixing the principles in mind. In the following pages are given a large number of test questions and problems which afford a valuable means of testing the reader's knowledge of the subjects treated.
Page 73 - W= = 833 pounds. EXAMPLES FOR PRACTICE. 1. An 8 X 8-inch .timber projects 8 feet from a wall. If its working strength is 1,000 pounds per square inch, how large an end load can it safely sustain ? Ans. 890 pounds. 2. A beam 12 feet long and 8 X 16 inches in cross-section, on end supports, sustains two loads P, each 3 feet from its ends respectively. The working strength being 1,000 pounds per square inch, compute P (see Table B, page 55). Ans. 9,480 pounds. 3. An I-beam weighing 25 pounds per foot...