In 1970, the U.S. Navy Officer in Charge of Construction RVN awarded a construction contract to a French construction contractor, Eiffel-Asie, to construct a bridge across the La Nga River on national highway QL-20 running north of Sai Gon to Dalat. This was the first construction contract awarded outside of the work the huge American construction company RMK-BRJ had been assigned. Subsequently, construction contracts were awarded to Vietnamese contractors as the RMK-BRJ contract was closed out.
I was assigned responsibility to administer the construction of the bridge out of our Long Binh office at the RMK-BRJ Camp. We regularly drove up national highway QL-1 and QL-20 to observe the construction.
This bridge was to replace a previous French-built bridge bombed by the Viet Cong.
U.S. Army engineers had replaced the dropped span with a Bailey Bridge span, as well as a pontoon bridge for heavy military traffic.
The new bridge spans were constructed with precast prestressed concrete beams furnished to the contractor by the Navy. These beams were fabricated by RMK-BRJ at their Saigon Island precasting plant. The French contractor constructed a steel truss "beam launcher" to pull the beams out to the span to be set.
After pulling the beams into the launcher on steel tracks,
the launcher was moved laterally into the position where the beam was to be dropped.
Steel barricades were erected around each pier to protect against mines dropped to drift into the piers to destroy the bridge.
Notice that the piers were solid walls across the width of the bridge.
Here is the bridge at completion.
Rock rip-rap had been added at each of the bridge abutments.
Since returning to Viet Nam, I have desperately wanted to figure out how to get a ride up QL-20 to see if the bridge was still there after the past 35 years. I luckily received that opportunity two weekends ago when a Vietnamese developer wanted to show me a property north of the bridge on QL-20. Here is the bridge today:
Notice that the piers are now round columns and beams. Sometime over the past 35 years, a dam was built on the La Nga River downstream creating a large reservoir which greatly widened the river at the bridge. It is possible that the river was dredged at this point so the piers had to be reconstructed with new foundations. The original beams are still there, though, as shown in this picture:
It also appears that the railings were moved outward by extending the bridge deck out to widen the bridge a bit.
This project was an important step for me as a young architect and construction professional. I am happy to revisit it, and it will stand for me as a reminder that some things will stay the same, other things will go away, and some things will change -- what counts is how it got there and how it will change to meet new needs.
