Bridge Defenses - Chu Lai and vicinity to Quang Ngai

During service in Vietnam in several different tactical areas of operations in the vicinity of Chu Lai,
the 1st Battalion 6th Infantry frequently was given the additional missions of protecting or reinforcing
several of the bridges over Route QL1 -- the main paved north-south highway along the coast.  For
example, on 17 Jan 69, the A Company, 1st Bn 6th Inf deployed forces at or near many of the key
bridges near Chu Lai:   part of the first platoon was at the An Tan Bridge (QL1-422 at BT 498 066),
while the remainder of the platoon was at the Ong Bau Bridge (thought to be QL1- 423 at  BT 430
109) and in a position at BT 507 077.  The second platoon was at the Ba Bau Bridge and BT 392
132, while the third platoon was at BT 515 122.  Use this link for maps of that area.

The smaller bridges were protected by local force military units (Popular Forces) who lived in the
villages with their families.  If the small numbers of soldiers on bridge defense duty were attacked,
then US forces were supposed to come to their aid to prevent destruction of the key links on
the highway.

An Tan Bridge (QL1-422) just to the west of the Chu Lai air field.  Hill 69 is 2.5 km farther west.
The large bridges on QL1 were protected by elevated observation towers positioned to allow the
defenders to fire underneath the bridges to target any Viet Cong who could swim there with explosive
charges. In addition, concrete or sandbag pillboxes and other defensive positions were situated at
either end of the spans. This photo of the guard tower at the An Tan Bridge (QL1-422 at BT 497
067) on highway QL1 just northwest of Chu Lai was provided by David Gibson.

Close-up of the Anton Bridge command post bunker in 1969.  Note the two-tier firing positions
protected by sandbags at the base of the tower.  Photo provided by Gerald "Whitey" White, A/1-6
Inf 1969.

Right next to the An Tan highway bridge was clear evidence of the need for defense - a blown RR
bridge was a constant reminder of the capability of the Viet Cong water sapper units.  1969 photo
from "Whitey" White A/1-6 Inf 1969.

During May - Jul 68, the An Tan bridge had been upgraded to a 300' steel stringer, timber pile bent,
timber pile abutment, class 60 structure.   At 0045 hr on 17 Nov 68, twenty feet of the center span
of the An Tan Bridge was destroyed by a  waterborne sapper attack, thus severing road traffic north
of Chu Lai on QL1.  Vietnamese soldiers from the 104th RF Company at the Ong Bau and Ba Bau
bridges were alerted.   At 0240 the Ong Bau Bridge (thought to be QL1 - 423 at BT 430 109,
a 150' long bridge) was blown after a successful ground attack, and a ground attack was launched
against the Binh Son Bridge south of Chu Lai.

     These early morning attacks on the bridges were not separate incidents, but were intended to
sever the main highway and to isolate targets in the early morning hours in the areas north and south
of Chu Lai:  0106 hrs, LZ Bayonet (hit by mortars, grenades, satchel charges, and ground attack
- 6 WHA); 0239 hrs, Hill 54 (hit with 25 rds 82 and 60mm mortars, B40 rockets, RPGs and ground
attack - 17 WHA, two ammo dumps on fire, 10 VC KIA); 0259 hrs, Hill 69 (hit with 60 rds of
82mm mortars, grenades - 4 KHA, 3WHA); 0300 hrs, LZ Fat City (hit with 7 rds mortars);  0326
hrs, Binh Son District (hit with mortars and ground attack - 56 VC KIA, 2 VC CIA, 7 AK-47s,
1 B-40 and 57mm RR CIA);  0327 hrs, LZ Dottie (hit w/26 rds 60mm mortar fire); 0353 hrs, LZ
Paradise (hit with 50 rds SAF);.  It appears that Binh Son was the primary target south of Chu Lai,
while further to the north at BT 249 169 an ARVN unit was attacked by two enemy battalions.

     While these multiple attacks severed two bridges over highway QL1, isolated the defenders
at many of the firebases, and prevented them from coming to each others aid, the enemy forces
were spread so thin that they were unable to strike any decisive blows.  Alert defenders at the
firebases, mutually supporting atrillry fires, and rapidly moving gunships were able to blunt the
enemy attacks.  That was little comfort, however, if you happened to be in the middle of a fight
for your life.  The enemy achieved the desired effect -- forces continued to be tied to defensive sites.

Poplar Force (PF) positions protecting the Suoi Loc bridge (BS623 865) on Highway QL-1 north
of LZ Dottie are shown in this 1970 photo by Earl Pogue.

These defensive emplacements are typical of those at the six or more small bridges between Quang
Ngai city and the Chu Lai base.  Note the strands of concertina wire that could be pulled across
the road and  the spider hole emplacements at the near end of the bridge.  All of the visible posts
supported strandsof wire.  The most likely avenue of approach for the enemy was through the gully
leading away to the right of the photo.  That area was covered by automatic weapons situated in
the bunker on the right. In 1970-71, soldiers from 1st Bn 6th Inf at LZ Dottie were to respond to
attacks on the bridge if necessary.

Note:  The photo also shows typical means of transportation:  balanced loads on a shoulder pole;
the Vietnamese "cowboy" on his motorcycle; and, the overloaded jeep.

All of these bridges were subject to attacks by superior Viet Cong forces, but they found it easier
to set charges in unguarded culverts.  The effect was the same--military traffic came to a halt.
The destroyed culverts or craters in the road were usually discovered by the early morning
reconnaissance overflight or by minesweep teams.  The road was usually open for traffic again by
1200 hours, and in nearly all cases before nightfall.

Railroad bridge at BS 592 921 over the Tra Bong river destroyed by Viet Cong saboteurs from
the water sapper company of the 402nd Sapper Battalion.  This scan of official US Army photo
III-SC 659125 at National Archives II, College Park, MD is dated 2 June 1970.

On 3 Dec 67, the 48th Local Force Battalion, 506A Local Force Sapper Company, 21st Local
Force Sapper Company, and the P-31 Local Force coordinated to attackthe Chau O Bridge and
Binh Son (District) Headquarters.  The Viet Cong succeeded in overrunning the headquarters.
Friendly artillery, air support and ground troops accounted for 35 VC KIA (Body Count).  The
Combat Action Report for that action is found at this link.

On 25 Dec 70, an enemy sapper unit was detected by PF security forces approaching bridge I-B-90
at BS 596 927, the main highway bridge over the Song Tra Bong at Binh Son in the 1st Bn 6th Inf
tactical area of operations.  One VC was killed in the attack and a 18"x18"x12" explosive charge was
captured.  One explosion was set off that slightly damaged a pier column.  Approximately two feet of
concrete flaked off down to the steel reinforcing bars.  The column was repaired by the 39th Engr Bn.

Today the old bridge at Binh Son has been replaced, but the bunker at the south end is still there.
Photo furnished by Vic Vilionis, USMC. Link here for current information and photos.

Bridge I-B-96 at BS 642 746 at Quang Ngai south of LZ Dottie.  On 30 Jan 71, an enemy sapper
unit attacked the bridge and destroyed or damaged four bridge columns located on the same side
of a pier. Bridge capacity was reduced to Class 30 traffic and was restricted to one lane.  Temporary
repairs were made by the 39th Engr Bn by constructing two Bailey Bridge piers on either side of the
damaged pier.  Repairs were completed on 5 Mar 71.  Photo provided by Earl Pogue 1/14 Artillery.

Select additional photos from the index at left of link to the 1st Bn 6th Inf Home Page