A laminated plastic beam of triangular cross section is built up by gluing together three sections (see figure). The beam is simply supported with span length L-360 mm. Calculate the minimum height of h if the allowable shear stress in the glued joints is 8 MPa. (Note: I = base and height being b and h respectively) for a triangle of b=30 mm h/3 h/3 h/3 q=10 N/mm L = 360 mm

A laminated plastic beam of triangular cross section is built up by gluing together three sections (see figure). The beam is simply supported with span length L-360 mm. Calculate the minimum height of h if the allowable shear stress in the glued joints is 8 MPa. (Note: I = base and height being b and h respectively) for a triangle of b=30 mm h/3 h/3 h/3 q=10 N/mm L = 360 mm

Mechanics of Materials (MindTap Course List)

9th Edition

ISBN:9781337093347

Author:Barry J. Goodno, James M. Gere

Publisher:Barry J. Goodno, James M. Gere

Chapter5: Stresses In Beams (basic Topics)

Section: Chapter Questions

Problem 5.8.5P: Two wood beams, each of rectangular cross section (3.0 in. x 4.0 in., actual dimensions), are glued...

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-14 A simply supported composite beam with a 3.6 m span supports a triangularly distributed load of peak intensity q0at mid-span (see figure part a). The beam is constructed of two wood joists, each 50 mm x 280 mm, fastened to two steel plates, one of dimensions 6 mm × 80 mm and the lower plate of dimensions 6 mm x 120mm (see figure part b). The modulus of elasticity for the wood is 11 GPa and for the steel is 210 GPa. If the allowable stresses are 7 MPa for the wood and 120 MPa for the steel, find the allowable peak load intensity q0maxwhen the beam is bent about the z axis. Neglect the weight of the beam.
A beam with a guided support and 10-ft span supports a distributed load of intensity q = 660 lb/ft over its first half (see figure part a) and a moment Mq = 300 ft-lb at joint B. The beam consists of a wood member (nominal dimensions 6 in. x 12 in. and actual dimensions 5.5 in. x 11.5 in. in cross section, as shown in the figure part b) that is reinforced by 0.25-in.-thick steel plates on top and bottom. The moduli of elasticity for the steel and wood are £s = 30 X 106 psi and £"w = 1.5 X 106 psi, respectively. Calculate the maximum bending stresses trs in the steel plates and rw in the wood member due to the applied loads. If the allowable bending stress in the steel plates is = 14,000 psi and that in the wood is (T.dV!= 900 psi, find qmiiX. (Assume that the moment at .fi, A/0, remains at 300 ft-lb.) If q = 660 lb/ft and allowable stress values in part (b) apply, what is Müm^ at B?
Two wood beams, each of rectangular cross section (3.0 in. x 4.0 in., actual dimensions), are glued together to form a solid beam with dimensions 6.0 in. x 4.0 in. (sec figure). The beam is simply supported with a span of S ft. What is the maximum moment Mmaxthat may be applied at the left support if the allowable shear stress in the glued joint is 200 psi? (Include the effects of the beams own weight, assuming that the wood weighs 35 lb/ft3.) Repeat part (a) if Mmaxis based on allowable bending stress of 2500 psi.
A propped cantilever beam A BC (see figure) has a shear release just right of the mid-span. (a) Select the most economical wood beam from the table in Appendix G; assume4 = 55 lb/ft, L = 16 ft, o~aw= 1750 psi, and raw= 375 psi. Include the self-weight of the beam in your design. (b) If a C 10 x 25 steel beam is now used for beam ABC, what is the maximum permissible value of load variable q? Assume üi = 16 ksi and L = 10 ft. Include the self-weight of the beam in your analysis.
A W 12 x 50 steel wide-flange beam and a segment of a 4-inch thick concrete slab (see figure) jointly resist a positive bending moment of 95 kip-ft. The beam and slab are joined by shear connectors that are welded to the steel beam. (These connectors resist the horizontal shear at the contact surface.) The moduli of elasticity of the steel and the concrete are in the ratio 12 to 1. Determine the maximum stresses r1 and xtin the steel and concrete, respectively. Note: See Table F-l(a) of Appendix F for the dimensions and properties of the steel beam.
A propped cantilever beam of length L = 54 in. with a sliding support supports a uniform load of intensity q (see figure). The beam is made of steel {<7y = 36 ksi) and has a rectangular cross section of width/) = 4.5 in. and height h = 6.0 in. What load intensity q will produce a fully plastic condition in the beam?
A hollow box beam with height h = 9.5 in., inside height/i, = 8.0 in., width? = 5,25 in., and inside width =4.5 in. is shown in the figure. Assuming that the beam is constructed of steel with yield stress ty= 42 ksi calculate the yield moment My, plastic moment MPand shape factor f.
A wood beam 8 in. wide and 12 in. deep (nominal dimensions) is reinforced on top and bottom by 0,25-in.-thick steel plates (see figure part a), (a) Find the allowable bending moment A/max about the z axis if the allowable stress in the wood is 1100 psi and in the steel is 15,000 psi, (Assume that the ratio of the moduli of elasticity of steel and wood is 20.) (b) Compare the moment capacity of the beam in part a with that shown in the figure part b which has two 4 in. × 12 in, joists (nominal dimensions) attached to a 1/4 in, × 11.0 in, steel plate.
A wood beam in a historic theater is reinforced with two angle sections at the outside lower corners (see figure). If the allowable stress in the wood is 12 M Pa and that in the steel is 140 M Pa, what is ratio of the maximum permissible moments for the beam before and after reinforcement with the angle sections? See Appendix F Table F-5(b) for angle section properties. Assume that ew= 12 GPa and E3=210 GPa.
A steel beam of rectangular cross section is 40 mm wide and 80 mm high (see figure). The yield stress of the steel is 210 MPa, (a) What percent of the cross-sectional area is occupied by the clastic core if the beam is subjected to a bending moment of 12.0 kN · m acting about the z axis? (b) What is the magnitude of the bending moment that will cause 50% of the cross section to yield?
A cantilever beam with a uniform load (see figure) has a height h equal to 1/8 of the length L. The beam is a steel wide-flange section with E = 28 X 106 psi and an allowable bending stress of 17,500 psi in both tension and compression. Calculate the ratio S/L of the deflection at the free end to the length, assuming that the beam carries the maximum allowable load. (Use the formulas of Example 9-2.)
The cantilever beam AB shown in the figure is an S6 × 12.5 steel I-beam with E = 30 × 106 psi. The simple beam DE is a wood beam 4 in. x 12 in. (nominal dimensions) in cross section with E = 1.5 x 106 psi. A steel rod AC of diameter 0.25 in., length 10 ft, and E = 30 x 106 psi serves as a hanger joining the two beams. The hanger fits snugly between the beams before the uniform load is applied to beam DE. Determine the tensile force Fin the hanger and the maximum bending moments MABand MDEin the two beams due to the uniform load, which has an intensity q = 400 lb/ft. Hint: To aid in obtaining the maximum bending moment in beam DE, draw the shear-force and bending-moment diagrams.