A portable gantry crane has a rated capacity of 25 kN. It was recently dented when hit by a load carried by the rail-mounted gantry. As a result, the owner wants us to evaluate whether the portable...

A portable gantry crane has a rated capacity of 25 kN. It was recently dented when hit by a load carried by the rail-mounted gantry. As a result, the owner wants us to evaluate whether the portable gantry can still carry the rated load. A member of the team is evaluating the dent and calculating the shear and moment capacity of the beam at the location of the damage. Our role is to calculate the peak shear generated at the damage site, B, if the crane is used to lift the full 25 kN. Creating an influence line will help us determine where to place the load.

a. Guess where to place a single point load to generate the peak shear at B (positive or negative). b. Develop the influence line for the internal shear at

B. Because this is idealized as a simply supported beam, the Table-of-Points Method is probably the fastest.

c. Identify where a single point load must act to generate the largest shear at B (positive or negative).

d. What is the peak shear generated at B (positive or negative) due to a live point load of 25 kN?

e. Comment on why your guess in part (a) was or was not close to your conclusion in part (c).