New Bridge New Road to Gonzaga Bay

Husband went for ride to Gonzaga Sunday took a side road off of the old road and found this. A whole new road is being graded and building a really nice bridge across one of the many washes.

That's gatta be one helluva wash for a bridge that large!

Any bets on whether or not it handles the first few gully washers that come thru there?

Tourism is down, traffic is down. All translates to more time for repairs and better roads for when the tourists are back.

Quote:

Quote: Originally posted by rts551 A local friend told us that so many bridges wash out because of the way the approach from the highway joins the bridge---the builders often short cut the process and use nothing but dirt fill. Then with the first big rains and floods, the dirts washed away and undermines the bridge. I certainly am no engineer, but we started looking at the bridges along highway 1 that were washed out last year and it does look like they had dirt filled approaches. Hope one of the engneers around here comments one way or another.

Here goes:

The bridges are built with sacrificial dirt approaches by design. Ninety percent or more of the cost of the crossing is in the concrete portion of the bridge so the designers strive to protect the major investment while minimizing the overall cost of the structure.

The bridges are built with the concrete sections in the deepest part of the arroyos. When the arroyo starts to flow it first passes under the concrete span section of the bridge. If the water flow exceeds the capacity of the concrete section, it washes out the dirt approach and increases the channel width. When the flow starts to recede, the water retreats back to the concrete section of the bridge allowing the dirt approach area to be dewatered and rapidly repaired.

That is why the road was back in operation at three of the four bridges in about a week after last Februaury's storms. The fourth bridge, at El Rosario, really exceeded the channel capacity and dropped a span into the arroyo in addition to washing out the approaches. That is why the bridge is still out of service. It takes a long time to repair the concrete sections.

This design theory is very evident on several bridges near Santa Maria and El Cien. The approches are built of dirt and are up to five feet lower in elevation than the concrete decks.

This design theory is also used on small dam spillways in the US. A portion of the embankment is built lower than the remaining crest of the dam in order to allow for a controlled breaching of the embankment and iniciation of flow down the spillway. It's called a "fuse plug" spillway.

Whew!

Quote:

Quote: Originally posted by RnR Quote: Originally posted by rts551 A local friend told us that so many bridges wash out because of the way the approach from the highway joins the bridge---the builders often short cut the process and use nothing but dirt fill. Then with the first big rains and floods, the dirts washed away and undermines the bridge. I certainly am no engineer, but we started looking at the bridges along highway 1 that were washed out last year and it does look like they had dirt filled approaches. Hope one of the engneers around here comments one way or another. Here goes: The bridges are built with sacrificial dirt approaches by design. Ninety percent or more of the cost of the crossing is in the concrete portion of the bridge so the designers strive to protect the major investment while minimizing the overall cost of the structure. The bridges are built with the concrete sections in the deepest part of the arroyos. When the arroyo starts to flow it first passes under the concrete span section of the bridge. If the water flow exceeds the capacity of the concrete section, it washes out the dirt approach and increases the channel width. When the flow starts to recede, the water retreats back to the concrete section of the bridge allowing the dirt approach area to be dewatered and rapidly repaired. That is why the road was back in operation at three of the four bridges in about a week after last Februaury's storms. The fourth bridge, at El Rosario, really exceeded the channel capacity and dropped a span into the arroyo in addition to washing out the approaches. That is why the bridge is still out of service. It takes a long time to repair the concrete sections. This design theory is very evident on several bridges near Santa Maria and El Cien. The approches are built of dirt and are up to five feet lower in elevation than the concrete decks. This design theory is also used on small dam spillways in the US. A portion of the embankment is built lower than the remaining crest of the dam in order to allow for a controlled breaching of the embankment and iniciation of flow down the spillway. It's called a "fuse plug" spillway. Whew!

We be driving that new road so much...we'll wear the asphalt down! Gonzaga Bay has got to be the top ten places in Baja...we love it there. Great beaches....snorkeling...FISHING is awful though

Hmmmmm, I wonder if folks fly in because there's no road to speak of and if a good road is put in, folks will drive there.

Waddya think? Maybe?

Coco's Offramp!