Panama Canal Locks - Construction

Construction

The project of building the locks began with the first concrete laid at Gatun, on August 24, 1909, by Philadelphia based company Day & Zimmermann (formerly known as Dodge & Day).

The locks at Gatun are built into a cutting made in a hill bordering the lake, which required the excavation of 5,000,000 cubic yards (3,800,000 cubic metres) of material, mostly rock. The locks themselves were made of 2,046,100 cu yd (1,564,000 m3) of concrete.

The quantity of material needed to construct the locks required extensive measures to be put in place to handle the stone and cement. Stone was brought from Portobelo to the Gatun locks; the work on the Pacific side used stone quarried from Ancon Hill.

Huge overhead cableways were constructed to transport concrete into the construction at Gatun. 85 ft (26 m) high towers were built on the banks of the canal, and cables of 2.5 in (6 cm) steel wire were strung between them to span the locks. Buckets running on these cables carried up to six tons of concrete at a time into the locks. Electric railways were constructed to take stone, sand and cement from the docks to the concrete mixing machines, from where another electric railway carried two 6-ton buckets at a time to the cableways. The smaller constructions at Pedro Miguel and Miraflores used cranes and steam locomotives in a similar manner.

Concrete is normally moulded in formwork, temporary structures which give shape to the concrete as it sets. For a simple construction, these would normally be made quite simply of wood, but the scale of the locks demanded extraordinary forms.

The forms for the walls consisted of towers, fronted with braced vertical sheets, 7.5 in (19 cm) thick, mounted on rails to allow the locks to be constructed in sections; a section of lock would be poured behind the form, and when it was set, the form would be moved to do the next section. Each of the twelve towers was 78 ft (24 m) high by 36 ft (11 m) wide. The forms for the culverts were made of steel, and were collapsible so they could be removed and moved along after each section of culvert had set. There were, in all, 33 forms for the centre and side-wall culverts, each 12 ft (3.7 m) long; and 100 smaller forms for the lateral culverts.

The Pacific-side locks were finished first; the single flight at Pedro Miguel in 1911 and Miraflores in May, 1913.

The seagoing tug Gatun, an Atlantic entrance working tug used for hauling barges, had the honor on September 26, 1913, of making the first trial lockage of Gatun Locks. The lockage went perfectly, although all valves were controlled manually since the central control board was still not ready.