Distribution

100     
100     
99     
98     
97     
97     
97     89     
97     89     
97     89     
97     89     
96     88     79
95     88     79               
95     88     78               
95     88     78               
94     87     78               
94     87     77               
93     86     77               
93     85     77     69          
93     85     76     68          
93     85     75     68          
92     84     75     68            49     
92     83     74     66            48     
91     82     73     65     57     48     
91     81     73     64     57     42     
91     80     72     64     57     41     
91     80     72     63     55     41     
90     80     70     63     50     40     28     17

Mean: 77.8, Median 81

Problem 1

A correct answer.

On part c), many people arrived at the correct answer using incorrect reasoning. The key point is that moving the support recudes the vertical reactions, which in turn reduces the moment. The incorrect soolution below bases it correct conclusion on the incorrect assumption that the vertical reaction remains 15 K.

Problem 2

Problem 3

Many people missed part d) which requires recognizing that the material has passed the yield point. A few people recognized that the material was inelastic, but concluded that the problem was unsolvable. The following is a clear and correct solution.

Problem 4

The potential stumbling block on this problem is that the point where the cable meets the structure is not dimensioned. The key to solution is to realize that the point lies somewhere along the line of the cable; the particular location on that line doesn't affect the reactions.

The following is a simple ans straightforward solution.

The following is a solution that converts the structure similar to one done in lab.

A similiar solution assumes the point of connection, and then goes on to solve.

Yet another approach to this problem...

Problem 5

a) Many people missed the upper portion of the tributary area, a width of 20 feet rather than 30 feet.

b) The following answer addresses the issue of connections, which is a good answer. Several people also discussed the issue of putting too much steel reinforcement in a reinforced concrete beam, which got full credit if it was explained well.

And another (less successful) approach...

c)