# Shear forces and bending moments on a box barge, formulas

1. Feb 28, 2010

### Helen p

1. The problem statement, all variables and given/known data

I need to determine loading sequences for a box barge - I have lots of information on the actual question, which I can't put up here because I have not attempted this question. I am really after some advice as to where I can find the equations I need. My (merchant navy) course doesn't provide course material for this class and my notes aren't very good because I was rushing to keep up.

I really need to know where to look for the equations for shear force and bending moments but I keep finding lots of different calculations and I just don't recognise any of them although I have given what I know below...

2. Relevant equations

I know that the buoyancy of the box-barge provides an upwards force and the cargo weight provides a downward force leading to shear force where these two meet.

I know that I need to use length (L, in m), beam (B, in m), depth (D, in m) and lightship displacement (Delta, in tonnes).

I have several loads which I must put into the ships compartments, not exceeding the maximum bending moment or maximum shear force - but I don't know where to find the formulas. does anyone know of a site that lists the formulas I need?

3. The attempt at a solution

I remember doing...

B= d x Pw (buoyancy = displacement x L x B)

and then stress analysis = buoyancy /L (giving buoyancy/meter)

I then recall something like...buoyancy goes up, cargo weight goes down and mass of structure goes down so a diagram can be produced...

mass of structure/length of compartment=downward forces
mass of structure/length of compartment=upward forces (in hold with no cargo)

This is my first post, and I'll probably get shot down but I thought I'd try. I'm struggling through an engineering degree that I am in no way qualified for but I'm sure it will all start making more sense eventually.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution