Mechanics of Materials I
Fall 2017
Assignment #2
Faculty of Civil Engineering
1- A glued lap splice is to be made in a 10 x 20 mm rectangular member at  = 20°, as shown
in the blow. Assuming that the shear strength of glued joint controls the design, what axial
fore P can be applied to the member? Assume the shear strength of the glued joint to be
10 MPa.
2- Short steel members have the cross sectional dimensions shown in the blow. They are
subjected to axial compressive forces of 100 KN each. If in each cross section the force is
applied to a point that cause no bending, determine the average normal stress in each
section. All dimensions are in mm.
3- A bar of variable cross section, held on the left, is subjected to three forces, P1= 4 KN,
P2 = - 2 KN, and P3 = 3 KN, as shown in the figure. Plot the axial stress along the length
of the bar. Let A1 = 200 mm2, A2 = 100 mm2, and A3 =150 mm2.
4- A plane frame has a pin support at A and roller supports at C and E (see figure). Frame
segments ABD and CDEF are joined just left of joint D by a pin connection. Find the largest
average axial stress in the frame.
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Mechanics of Materials I
Fall 2017
Assignment #2
Faculty of Civil Engineering
5- An L-shaped reinforced concrete slab 3.6 m  3.6 m (but with a 1.8 m  1.8 m cut-out) and
thickness t = 230 mm, is lifted by three cables attached at O, B and D, as shown in the
figure. The cables are combined at point Q, which is 2.1 m above the top of the slab and
directly above the center of mass at C. Each cable has an effective cross-sectional area
of Ae = 77 mm2.
(a) Find the average stress in each cable.
(b) Add cable AQ so that OQA is one continuous cable, with each segment having force
T1, which is connected to cables BQ and DQ at point Q and repeat parts (a). (Hint:
There are now three force equilibrium equations and one constraint equation, T1 = T4)
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