A simple log bridge in a remote area consists of two parallel logs with planks across them (see figure). The logs arc Douglas fir with an average diameter 300 mm. A truck moves slowly across the bridge, which spans 2.5 m. Assume that the weight of the truck is equally distributed between the two logs. Because the wheelbase of the truck is greater than 2,5 m, only one set of wheels is on the bridge at a time. Thus, the wheel load on one log is equivalent to a concentrated load W acting at any position along the span. In addition, the weight of one log and the planks it supports is equivalent to a uniform load of 850 N/m acting on the log. Determine the maxi mum permissible wheel load W based upon (a) an allowable bending stress of 7.0 MPa and (b) an allowable shear stress of 0.75 MPa.
A simple log bridge in a remote area consists of two parallel logs with planks across them (see figure). The logs arc Douglas fir with an average diameter 300 mm. A truck moves slowly across the bridge, which spans 2.5 m. Assume that the weight of the truck is equally distributed between the two logs. Because the wheelbase of the truck is greater than 2,5 m, only one set of wheels is on the bridge at a time. Thus, the wheel load on one log is equivalent to a concentrated load W acting at any position along the span. In addition, the weight of one log and the planks it supports is equivalent to a uniform load of 850 N/m acting on the log. Determine the maxi mum permissible wheel load W based upon (a) an allowable bending stress of 7.0 MPa and (b) an allowable shear stress of 0.75 MPa.
Solution Summary: The author explains that the maximum permissible wheel load is 28.6 kN. The maximum bending moment occurs at x=2.5/2m.
A simple log bridge in a remote area consists of two parallel logs with planks across them (see figure). The logs arc Douglas fir with an average diameter 300 mm. A truck moves slowly across the bridge, which spans 2.5 m. Assume that the weight of the truck is equally distributed between the two logs.
Because the wheelbase of the truck is greater than 2,5 m, only one set of wheels is on the bridge at a time. Thus, the wheel load on one log is equivalent to a concentrated load W acting at any position along the span. In addition, the weight of one log and the planks it supports is equivalent to a uniform load of 850 N/m acting on the log.
Determine the maxi mum permissible wheel load W based upon (a) an allowable bending stress of 7.0 MPa and (b) an allowable shear stress of 0.75 MPa.
A new art exhibit featuring mobile works is going up in the Holland, MI, area. One piece is shown in the figure. The 155-N uniform beam is pinned to the ground by a pivot. The beam is supported by a cable (attached to the center of the beam) to allow for each of the shoes to hang freely. Each individual shoe has a weight of 9.5-N.
If one shoe is attached two-fifths of the way up the beam and another shoe is attached and three-fifths of the way up the beam, with θc = 16.5° and θb = 33.6° as shown in the figure, what is the tension in the cable, in newtons?
What is the x-component of the force, in newtons, that the pivot exerts on the bottom of the beam? Use the coordinate system specified in the figure.
What is the y-component of the force, in newtons, that the hinge exerts on the bottom of the beam? Use the coordinate system specified in the figure.
a beam is supported by a pin support at A and
a roller support at B. For this question, leave your answer in terms of
the variables w and L.
(a)
Using equilibrium of the full beam, find the support
forces at A and B.
(b)
First section: Make an arbitrary cut between points
A and B. Take the distance of the cut to be x along the beam
from point A. Draw the free-body diagram for the left section
and find functions for the internal shear force, V(x), and bending
moment, M(x), in the section of the beam between A and B.
(c)
Second section: Repeat part (b) for the section of the
beam between B and C. Take x to still be the distance from point
A.
(f)
Find the value of x at which V(x) = 0.
The internal bending moment reaches a maximum at
the same point as V(x) = 0. Find the maximum bending mo-
ment.
pin
Sketch the shear and bending moment diagrams.
B
L
W
C
roller
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.