The floor of a bridge will rest on stringer that will be simply supported by tra
ID: 1920233 • Letter: T
Question
The floor of a bridge will rest on stringer that will be simply supported by transverse floor
The floor of a bridge will rest on stringer that will be simply supported by transverse floor beams, as in Fig. a. The ends of the beams will be connected to the upper joints of two trusses, one of which is shown in Fig. b. As part of the design of the bridge, it is desired to simulate the effect on this truss of driving a 3-kip truck over the bridge. Knowing that the distance between the truck's axies is b = 7.5 ft and assuming that the weight of the truck is equally distributed over its four wheels, use computational software to calculate and plot the forces created by the truck in members BH and GH as a function of x for 0 x 57.5 ft. From the results obtained, determine The maximum tensile force in BH, The maximum compressive force in BH, The maximum tensile force in GH. Indicate in each case the corresponding value of x.Explanation / Answer
A Pratt steel truss is to be designed to support three 50-kN loads as
shown. The length of the truss is to be 12 m. The height of the truss and
thus the angle u, as well as the cross-sectional areas of the various members,
are to be selected to obtain the most economical design. Specifically, the
cross-sectional area of each member is to be chosen so that the stress (force
divided by area) in that member is equal to 160 N/mm2
, the allowable stress
for the steel used; the total weight of the steel, and thus its cost, must be
as small as possible. (a) Knowing that the density of the steel used is
7800 kg/m3
, write a computer program that can be used to calculate the
weight of the truss and the cross-sectional area of each load-bearing member
located to the left of DE for values of u from 20