Bulldozers come first. This slogan crystallizes the role that engineering and construction played in World War II, where combatants were far more mobile than in previous conflicts. Wartime plants for mass production of tanks, planes and weaponry were needed. Shipyards and naval bases to support a two-ocean navy were vital. Before pilots could be trained, air bases had to be constructed. The phrase was also the title of a 1944 book that was a collection of reports by five ENR war correspondent editors, who travelled over 100,000 miles across the globe documenting the work of American military engineers and construction units.
After the December 1941 attack on Pearl Harbor, Hawaii, the territory of Alaska was seen by the U.S. as vulnerable to Japanese attack. Since there was no overland connection, U.S. military leaders quickly decided to build a highway link between northern British Columbia and Fairbanks, Alaska. By March 1942, crews were slashing a primitive right-of-way. Shallow-rooted spruce trees were knocked down by bulldozers. ENR editor Harold W. Richardson described how muskeg bogs were crossed by assembling corduroy mats of poles and brush. Many streams and rivers were spanned with pontoon bridges until temporary pile trestles could be driven later. Yukon permafrost was so unstable that it had to be covered with 4 ft of trees and brush before gravel was placed. Much of the machinery used was Civilian Conservation Corps gear, with broken machines often stripped to repair others. Working around the clock, 10,000 troops—one third of them Black—living in tent camps were able to complete the 1,700-mile route in under eight months.
After Japan captured two of the Aleutian Islands, Richardson reported on the rushed construction of runways on several other islands. To overcome the lack of local materials, engineer troops relied on a product recently developed by the U.S. Army Corps of Engineers known as pierced planking. These steel sheets, ¼-in. thick, 16-in. wide and 10 ft long, were pierced with 3-in.-dia cupped holes and fringed with a series of slots and hooks so they could be interlocked to form a tight, smooth mat. On Adak Island, bulldozers scraped sand over a tidal swamp and pierced planking was laid down. Four days after an amphibious landing, a 3,000-ft-long runway was operational.
Formation of the SeaBees
After Pearl Harbor, Japanese forces captured Guam and Wake Island as well as Cavite City in the Philippines, making the construction of advance base facilities by civilian contractors untenable. “With every advanced base a potential point of combat, and every newly won beachhead a construction site, only naval personnel under military command could do the job. So, for the first time in its long history, the Navy decided to ‘roll its own’ in the construction business.” This was how the Navy’s Construction Battalions (Seabees) were founded. Their officers were virtually all degreed engineers, with extensive experience in construction or public works, while the enlisted men brought craft skills.
Editor-in-Chief Waldo Bowman spent time at Camp Bradford in Virginia, where enlisted Seabees were assigned to 15 specialist classes, ranging from hut erection and firefighting, to pontoons and dry docks, to water purifiers and salt water evaporators, to welding to dynamiting. He saw teams erecting and dismantling steel storage tanks and erecting Quonset huts. Editor Nathan A. Bowers hopscotched across the Pacific, reporting on Seabee activity in 29 bases. “At Guadalcanal, Tarawa and elsewhere, construction battalions debarked with the early waves of combat troops, started construction work while the fighting was in progress, and had badly blasted [Japanese] airfields ready for service a few days after the attack on the bases began.” Eager to tackle other problems, they also repaired torpedoed ships, blasted out ship channels, operated saw mills, and overhauled broken-down machinery of all sorts.
Making a virtue out of a necessity, the only surfacing material for air strips available on the Pacific islands was coral. Bowers described how the Seabees learned to judge the coral’s various qualities, taking moisture conditions into account in order for it to compact and set effectively. Well-built coral runways were found to require less maintenance and equipment than air strips composed of any other local material or even pierced planking.
Pontoons proved to be highly versatile assets as American forces advanced across the Pacific. Thin steel plate was welded into 5 ft x 7 ft x 7 ft boxy units that were buoyant. Joined together in various configurations they formed barges, dry docks, piers, bridges, and even ferries or tug boats if equipped with outboard motors. Bowers described a wharf at Noumea, New Caledonia, comprised of pontoons strung together in cells eight across and 62 long, which at 40 ft wide and 434 ft long allowed larger ships to unload. Such assemblies were valuable in places where piles and pile drivers for building traditional wharves and piers were unavailable. The pontoon wharf in Noumea was constructed in four weeks by 24 Seabees working during 12 daylight hours each day as no lights were permitted at night.
Bowman also reported on construction work in Britain, which served as a staging area for 1.5 million American troops preparing for deployment to North Africa and France. U.S. military engineers built dozens of airfields in Britain from which American bomber planes carried out missions over Germany. They also built hundreds of barracks, an ordnance base, oil depots, and an antitank range that contained “three miles of crazy-quilt railroad tracks on which targets moved.”
With the bulk of the ground fighting taking place on the eastern front, and much of Russia’s industrial base destroyed, the Allies pledged to supply large quantities of vehicles and weapons to their Soviet ally. The primary route they devised was the Persian supply corridor. American engineers set to work in 1942 to upgrade the limited 800-mile railway extending north from the small port of Bandar Shahpur on the Persian Gulf to Bandar Shah on the Caspian Sea, supplementing steam locomotives with diesels. The rail line and companion highway traversed rugged desert terrain and mountain passes over 7,000 ft above sea level. Crews erected a GM truck plant and a Douglas Aircraft assembly plant. Bowman spent two weeks there, reporting on how the workforce had to contend with sandstorms, floods, bottomless silt and malaria. Freight trains and long truck convoys ferried such materiel as Studebaker US6 trucks and canned food northwards, constituting 45% of all U.S. Lend-Lease aid to the Soviet Union.
One piece of equipment that proved invaluable to the Allies and has since gone into wide use globally was the Bailey Bridge. Invented by Donald Bailey, a British civil servant, in 1940, it first saw service in the North Africa campaign in 1942. A portable, prefabricated truss bridge, each of its 10-ft-long, 5-ft-high sections consisted of 17 parts. Each 570-lb, cross-braced rectangular unit could be carried by four soldiers and took no special tools or heavy equipment to assemble. The modular units could be bolted together to form spans of over 200 ft, and were strong enough to support tanks. They enabled units to advance across rivers or ravines in areas where retreating enemy forces had destroyed crossings.
Frontline Engineering
Following the success of the Normandy invasion in June 1944, made possible by artificial “Mulberry” harbors, U.S. army engineer units tackled the reconstruction of the port of Cherbourg, which had been wrecked and mined by the retreating Germans. Millions of man-hours were spent clearing debris, building 5 miles of new wharves and paving hundreds of thousands of sq ft of beach for use by landing craft and amphibious trucks. The remade harbor had 25 times the cargo-handling capacity of the prewar port. Three other Army engineer regiments rebuilt additional wrecked French ports.
As Allied forces advanced through France and Belgium in late 1944, engineers’ main task was rehabilitating 7,000 miles of railway to move supplies. Hundreds of railroad bridges wrecked by the Germans were restored to service using three types of prefab bridges developed by the British: the UCRB, a parallel-chord, Pratt-type truss span; LST and HST, light steel and heavy steel trestling; and RSJ, rolled-steel joint spans. One notable effort was the restoration of a 75-mile section of track involving 6,000 workers who repaired seven bridges, three railroad yards and built new water tanks in 48 hours, enabling supplies to reach Gen. George S. Patton’s Third Army.
One dramatic episode late in the war involved the railroad bridge over the Rhine in Remagen, Germany, a triple-span tied arch with spans of 278 ft, 513 ft and 278 ft. As an American armored division approached, it learned from a German prisoner that the Germans had placed explosives on the bridge and were minutes away from detonation. American artillery fire, grenades and rifle fire killed the Germans stationed on the bridge, but one of the planted charges exploded, seriously damaging a shoe on the upstream truss. Some tanks and troops crossed, establishing the first beachhead east of the Rhine. Scores of troops set to work repairing the bridge with all possible speed, replacing deck beams, welding, cutting and hammering for ten days. German artillery less than a mile away continued targeting the bridge, killing a number of the soldiers and inflicting additional damage. On March 17, 1945, only ten hours before a critical splice was to be made, the bridge collapsed, taking the lives of 28 more Allied soldiers. Bowman himself had spent that morning on the bridge, two hours before it collapsed, and published a detailed article with photos and sketches.
Over 700,000 American soldiers and sailors served in engineering units during World War II; 325,000 were Seabees and the remainder with the Army.
