Temporary Timber Bridge over the Great Kei River
Joseph NEWEY: Project Architect
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A temporary, small scale timber bridge was designed and constructed by the civil engineer Joseph Newey as a military bridge over the Great Kei River for the 1877-78 War of Ngcayecibi. Newey was then in the process of constructing the more substantial Great Kei Wagon Bridge alongside. Authority for the construction of the Temporary Bridge had been provided in a Memorandum of the Hon. Commissioner of Crown Lands dated 7 October 1877.
Historic photographs of the temporary bridge have not yet been sourced but the original working drawing is still extant . The original drawing comprises a plan and an elevation and has been used to inform the detailed description that follows. An interesting feature of the Newey drawing is that three of the circular columns of the wagon bridge are shown a short distance away on the downstream side of the timber bridge.
The temporary military bridge was an interesting and well considered assembly of substantial timber elements, bolted together on site. It consisted of two sets of paired, triangulated fish-belly lattice girder trusses - each with a span of 100' (30,48 m). The two paired lattice girder trusses met at a point at about 25' (7.62 m) above the centre of the 'ordinary run' of the river bed.
Each pair of lattice girder trusses was supported on two pairs of timber columns - each pair separated from the next by a distance of 50' (15,24m) and placed to support each girder truss 25' (7.62.) from their ends.
The timber columns were probably sheathed with a sharp pointed metal tip and would have been hammered as piled columns deep into the river bed.
It is assumed that the piled columns would have been installed first. The fish-belly lattice girder trusses would then have been assembled on the dry river bed, between the paired columns. Each pair of trusses would then have been lifted up, between the columns, and supported on pairs of horizontal beams bolted to the columns. The girders would then have been incrementally launched towards the meeting point at the centre of the river. Once in position the formal bolted connections to the columns would have been made.
The gap between each pair of trusses was triangulated between the bottom chords to ensure adequate rigidity of the bridge structure. The gap between the two top chords was spanned by heavy timber baulks at regular centres, which were in turn overlain with planking parallel to the length of each span, to form a bridge deck of about 9' 6" wide (2.9 m). The bridge deck on each side had a nominal slope up, towards the central meeting point. Balustrades were not provided and crossing the bridge on horseback would not have been for the faint-hearted!
The approach to the bridge on the right hand bank was via a simple extension of the bridge deck - supported on a single pair of columns and a small earth embankment. The approach on the left hand bank (on the Transkei side) was formed with a more substantial extension of the bridge deck - this time supported on five paired timber columns and a small earth embankment.
Three of the columns on the downstream side of the bridge were additionally supported against flood waters by diagonal buttresses founded on the river bed. The two outer pairs of columns - closest to the bridge approaches - were additionally braced on the inner side to the bottom chord of the lattice girders, to provide some extra stability.
Surgeon Norbury of the Naval detachment, who crossed into the Transkei in 1877, left the following description of the temporary military bridge:
"As we approached the Kei we lost the mountain breezes, and the heat became much more oppressive. A short distance from the right bank we passed a small encampment of the Frontier Armed and Mounted Police (F.A.M.P.), which was placed there to prevent any [Xhosa] taking possession of the drift, or destroying the bridge. This bridge across the Kei was a long wooden structure, sufficiently wide for horsemen to pass singly, but the foundations of a much finer and more durable one were being laid."
Commandant G. Hamilton-Browne commanded a detachment of Pulleine's Rangers and left a contemporary description of his crossing of the temporary military bridge. The Rangers had largely been recruited from the navvies working on the construction of the East London-to-Queenstown railway line and were rough individuals, given to drunkenness and looting. While marching to the Transkei they purchased alcohol from the hotel-keeper at the Kei River and became uncontrollable, taking shots from the wooden bridge at their officers who were swimming in the Kei River to cool off.
The temporary military bridge remained in place for a brief period until it was washed away by a flood on 2 April 1879.
The author is employed by Osmond Lange Architects in East London and they utilise 3-D modelling software. During the Covid-19 lockdown of 2020, a colleague - Philip May - utilised a copy of Joseph Newey's working drawing (photographed from the original in the Cape Archives by Dennis Walters) to reconstruct the temporary bridge as a 3D CAD virtual model. The 3D model was in turn used to generate an updated set of working drawings, various perspectives and to record various short film clips 'flying' over and through the bridge, which are loaded on YouTube.
These notes were last edited on 2021 06 15
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