Railway barrier collision load 1

[Jean_Wong]

Good day!
I have been assigned to design barrier for a railway. Here is the definition from our design criteria:

"For Piers and other guideway support element situated in less than 3m from the edge of adjacent highway shall be designed for horizontal static force of 1000kN, unless protected by suitable barriers. The force will be applied at an angle of 10 degrees from direction of road traffic at 1.2m above ground."

If take the perpendicular component of the force, it's around 174kN which generates 208.8kN-m moment at the base of 1.2m height. The barrier is 1.2m high, and 0.2m thick. What should be my design length as 208.8kN-m moment seems too large for a 1.2x0.2x1.0m dimensions?

 

[Lomarandil]

Is your barrier continuous, or segmented (maybe the wrong term, I'm thinking of something like K-rail)?

What are the dimensions of the vehicle (presumably a train?) applying said load?

 

[bridgebuster]

I'm a little confused but that's par for the course with me. The provision you're quoting is similar to AASHTO LRFD about applying a 300 kip concentrated load to an unprotected pier; metal highway guide rail doesn't count as protection. In AASHTO a concrete barrier protecting a pier is designed for what they call TL loading, which is a function of the the traffic volume and percentage of trucks, not the 300 k load. The 300 k is applied only to the unprotected pier not the barrier.

What's below your bridge, highway or railway? If it's a highway there is probably a standard concrete barrier that can be used to protect the pier. If you're designing a crash wall that is integral with the pier you can spread the 1000kn. If you look at an AASHTO example for bridge parapet design for impact loads you'll see how it's done. It's based on yield line theory.