Push wall forces. 1

[imnotclever]

I’m designing a salt storage facility. One wall is going to be a push wall, where the payloaders push the salt into their bucket. This wall is going to have salt about 13’ high on it and will be supported at the top by precast plank. The wall itself is a simple basement wall.

I’m wondering if anybody has designed a push wall before and how did you determine the force of the payloaders ramming against the wall to load their buckets?

 

[aggman]

I have been involved in something before that was somewhat like your situation. If I remember correctly it was a pretty nasty problem. If you have to design for the impact of a wheel-loader on a wall, the forces will get high pretty fast. As a start, make the owner specify what specific piece of equipment that you should design for. (Hopefully the manufacturer is still around) Then you can get product literature and probably can actually talk to the manufacturer to help with the loadings. They should be able to give you the maximum static push of the machine. This with a generous impact factor (say 2 or 3 to 1) would be one load. Another way to approach this (and the approach that I feel more confortable with) is to analyze the wall using the energy method. You should be able to reference Lincoln Arc Welding (Design of Steel Structures by Blodgett). Section 2.8 is on Impact loads. What you will have to end up doing is assume an initial velocity (based on the max speed say in first gear) and then determine the time required to stop the machine based on the stiffness of the wall. The stiffer the wall, the higher the loads. Be sure to include the effects of the load spreading out over the wall area. You will quickly find that you will likely need some sort of rubber or plastic which has a high modulus of resiliance to help reduce the impact load, i.e. deflect more and allow more deceleration time. This will help reduce the loads to a more manageble state. Anyway I would start with taking a look at the Design of Steel Structures. This will get you going in the right direction. Once you feel like you are half-way up to speed on loads I would contact the manufacturer and discuss this with them. They likely can help you determine the loads as well.