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Ohio is looking at adding the steel post trailing end anchorage to our standards as an option (in addition to the wood post system). A couple questions came up from industry partners and we are looking for guidance:

1. Can the standard soil tubes be pre-punched to accept a soil plate so that if there is an underground obstruction/utility/rock, a soil plate could be added in the field and the standard tube could be cut to a prescribed length to shallow up the installation depth of the soil tube/lower post assembly? Is this OK/does this affect crashworthiness? 


2. How is this end anchorage installed behind curb? Can blockouts be added so that posts can be kept in line with a standard run of MGS guardrail?


3. One of the suppliers has asked to drill and tap the holes in the foundation tube for the ground strut connection after galvanizing. They claimed that they have asked for and received permission from MwRSF to do this for shipment to other states. Is this OK?

Responses to your questions are provided in red below.

1. Can the standard soil tubes be pre-punched to accept a soil plate so that if there is an underground obstruction/utility/rock, a soil plate could be added in the field and the standard tube could be cut to a prescribed length to shallow up the installation depth of the soil tube/lower post assembly? Is this OK/does this affect crashworthiness? 

While the use of soil plates may be a feasible option, it would likely require further research. To date, all of the work on the steel and wood post trailing anchorages under MASH TL-3 has used full depth foundation tubes. If one wished to use soil plates, additional research would likely be needed to determine the size and embedment of those plates to develop similar resistance to the full-depth tubes. This could likely be done through a combination of analysis and dynamic component testing.

2. How is this end anchorage installed behind curb? Can blockouts be added so that posts can be kept in line with a standard run of MGS guardrail?

To date, no guardrail anchorage system has been evaluated to MASH criteria when placed adjacent to curbs. As such, the system performance of the steel-post, trailing-end anchorage system in combination with curbs is unknown, and therefore it is not recommended for use until further evaluation has been conducted. Further, the only successfully MASH TL-3 tested configuration of the MGS in combination with curbs was with the MGS when placed 6 in. behind a 6- in. tall AASHTO Type B curb. However, this configuration utilized soil backfill, which would prevent proper installation of the breakaway steel posts in the trailing-end anchorage as the strut, yolk, and post-to-foundation tube attachment bolts would be located below ground line. Therefore, use of the steel-post, trailing-end anchorage system would require either the development of a modified system with a shorter rail height relative to the ground line or the successful evaluation of the MGS positioned farther behind the curb and with a 31-in. rail height relative to the ground. This would require full-scale crash testing as there are some concerns with wedging the small car between the anchor cable and the curb and causing occupant risk issues.
 

3. One of the suppliers has asked to drill and tap the holes in the foundation tube for the ground strut connection after galvanizing. They claimed that they have asked for and received permission from MwRSF to do this for shipment to other states. Is this OK?

This is an acceptable practice and we did provide guidance to a supplier on this. The proper construction involves:

1. Remove bolts (f3) from the tube.
2. Weld plate (c3) to tube (b2) then tap holes in plate (c3) and tube (b2) to accept bolts (f3)

Let us know if you have any further questions.