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King River Bridge
near Crotty, Tasmania.

The steel span

Detail from a 35mm transparency c.1985. Courtesy of Greg Schofield.

Location

This 160 foot [49m] steel truss bridge carried the North Lyell Railway over the King River between Crotty and Linda Valley, Tasmania. Its position is shown on the map below as "King River Bridge", which is how it was known to the people who designed and built it. It is now submerged in Lake Burbury.

A steel truss bridge of a different type carried the Mount Lyell Railway over the King River at Teepookana (see map below and SLV photo). By a process of elimination, it has become known to many people as The King River Bridge.

Map showing the King River Bridge near Crotty on the North Lyell Railway and the King River Bridge at Teepookana on the Mount Lyell Railway.

Portion of a map entitled "Western Towns and Railways, 1900-1910". Reproduced, with permission, from Blainey, G. The Peaks of Lyell, Melbourne University Press, 3rd edn, 1976, p.312. © Geoffrey Blainey AC.

Story of the bridge
from Monash & Anderson's point of view.

The North Lyell Railway was built for the North Mount Lyell Copper Co. Ltd. by contractors Baxter & Saddler. Monash knew both Baxter and Saddler well, having represented them in disputes over the finalisation of government railway contracts. In February 1899 Monash was domiciled in Perth winding up just such a case. His partner J T N Anderson, together with their trainee engineer/draughtsman, Arthur Timmins, therefore handled the initial enquiry from B&S in Melbourne.

The contract proposed by B&S imposed a tight schedule for completion of the bridge, and Anderson tried to interest the renowned American steel bridge expert J A L Waddell in designing the structure and having it fabricated in the US for shipment in parts to the site. He sent him a diagram of the proposed bridge, as shown below (redrawn).

The first proposal for the steel truss span. Note that the steelwork is placed below the level of the railway. The approach spans were of timber. Gormanston is to the left and Kelly Basin to the right. (Based on a pencil sketch in the Reinforced Concrete & Monier Pipe Co Collection, University of Melbourne Archives. Undated, but probably 1 March 1899.)

Waddell declined the offer, deterred by the short time period allowed, and by the penalty payments envisaged for failure to meet the deadline.

On 19 March, Monash arrived in Melbourne for a brief visit and became involved in the project, holding discussions with Saddler and with Thomas Timmins, manager of the Melbourne works of Dorman Long & Co. the British steel company. (Thomas was Arthur's father.) Monash provided legal advice concerning the proposed contract between B&S and the Copper Company and contributed ideas on launching the bridge with the aid of a temporary trestle at mid-stream.

Arrangements were made for the design and fabrication of the steelwork to be carried out by Dorman Long under contract to B&S. M&A were to act as consulting engineers - supervising the design, detailing and fabrication of the bridge - and as proof engineers to conduct an independent check on its strength. M&A also took responsibility for the design of the concrete supports at the ends of the steel span (described sometimes as 'abutments' and sometimes as 'piers').

Monash returned to Perth about 12 April. Anderson wrote the specification for the bridge, in consultation with Saddler and Thomas Timmins. Dorman Long supplied the first working drawings of the bridge, forwarded via B&S to M&A. Anderson checked the calculations and practical aspects of the design and gave Dorman Long the go-ahead to start cutting the steel to size. The bridge shown in the main drawing is now of the 'through' type: the sleepers are supported on the bottom chords of the trusses, and the train on entering the bridge passes through a portal.

Half elevation, from the general steelwork drawing. Only the left half of the bridge is shown, the other half being a mirror image, except that there was a roller bearing at the far end. The centre (mid-span) is indicated by the vertical line at right. (J Thomas Collection. Undated. Possibly a copy of the Dorman Long original, and traced about April/May 1899.)

At this stage Alfred Clayton, the Copper Company's Engineer, decided that the Dorman Long design needed to be strengthened. He required heavier uprights for the portal frames at each end of the bridge, and additional horizontal bracing across the top and bottom of the bridge. Anderson argued in a strongly-worded letter that Clayton's ideas were out-dated and a waste of material. Timmins snr complained that the additions were excessive, would cause unnecessary cost and delay, and would damage the truss members to which they were attached. However, it seems that Clayton prevailed. About this time, he appointed a Mr Ratcliffe as Inspector to oversee fabrication and trial assembly on behalf of the Copper Company.

In June, Anderson and Timmins jnr obtained details of the bridge site from the Copper Co's engineers in Tasmania, enabling them to design and draw the concrete abutment-piers. Routine liaison, and supervision of fabrication and assembly, continued throughout May and June as the bridge was put together in the yard of the Otis Company. Monash returned to Melbourne about 4 July, joining Anderson in supervising the final stages of fabrication and assembly. Baxter allowed Dorman Long an extra fortnight to finish the bridge.

On 28th July the chocks were removed and the bridge, sitting in the Otis yard, bore its own weight for the first time (about 80 tons). It seems to have been Arthur Timmins's job to arrange the celebratory luncheon, attended by leading politicians and engineers. M&A were told by Saddler that they could invite a few guests, and suggested Catani, Mountain, Forrest, and the Editor of the Building, Mining and Engineering Journal.

The Argus for 4 August 1899 contained a report on the luncheon, with list of guests. For more on Catani, Mountain, and Forrest see our People Index.

It was at this late stage that Monash, assisted by Arthur Timmins, made another, detailed calculation of the forces in the members of the bridge under various loading conditions due to a passing train. The need for this probably came from the fact that under the relevant Railway Act, the Copper Company had to provide detailed information to government engineers so that they could check the strength of the bridge. The exercise produced an interesting example of graphical analysis signed on behalf of M&A in Monash's hand. [See reduced copy 880 × 557 pixels.]

Our still incomplete research has provided few clues as to the date of launching. A temporary bridge had been built on the site, strong enough to carry materials and workers beyond the river and on towards Gormanston. The permanent bridge was to be assembled on the bank adjacent to it. A letter dated 12 September 1900, apparently in response to a complaint from Clayton, says that the new bridge was now fully assembled and ready to launch; but that removal of the temporary bridge had been delayed so that the Copper Company could despatch a first token consignment of ore from Gormanston to Kelly Basin. A report in The Argus of 6 November 1900 states that, "the necessary alterations having been made to the aerial ropeway to Linda Valley, and the permanent bridge over the King River completed, a start will be made to-morrow to send daily consignments of ore to Kelly Basin for shipment". Thus the launch probably took place between 12 September and 6 November 1900.

M&A's account for their services, sent to B&S in August 1899 reads:

To professional services in connection with the King River Bridge for the North Lyell Railway as under:
Feby. to
Sep/99.
To preparing specifications, revising drawings, supervision throughout, and all negotiations and correspondence during progress of works, also stress diagrams &c. &c. for Steel Girder Bridge 160' span value say £2000 -- 2% on same =40 0 0
 To preparing complete designs for Concrete foundations, abutments & holding down arrangements, and negotiations and correspondence re same -- Value say £800 -- 2% on same =16 0 0
  £56 0 0

Image from a 35mm transparency c.1985. Courtesy of Greg Schofield.

Appendix

Anderson's contact with J A L Waddell

On 5 August 1897, Waddell wrote to Professor Kernot at the University of Melbourne, inviting him to act as Waddell's agent or representative in Australia, or to suggest someone who might be interested. He explained that he had "established a large and successful practice in bridge designing in the United States" and had begun to expand abroad. "I need a good, live, man of some influence, who would be able to talk in a straightforward manner to the parties desiring bridges". "I would give him all the data for doing the talking, and would furnish him with considerable bridge literature which I have written ..." This would include his book De Pontibus, then in course of preparation. Kernot passed the letter on to Monash & Anderson.

The partners expressed interest, and Waddell was keen to accept them. In July 1898 he sent a detailed contract, already signed by him, and a copy of De Pontibus. However, the partners delayed signing, and may never have done so. In June 1899 Waddell decided to enter the competition to design the Sydney Harbour Bridge, and asked M&A to act as his agents for the competition and during the detailed design process, if he were successful. They exchanged correspondence on the matter until August 1901, when they sent him a cable to say they were no longer able to act for him.

Our research notes do not contain sufficient information to explain the reasons for M&A's failure to take up the agency. They initially pleaded pressure of work, and it is possible that they saw greater opportunities offered by the Monier arch bridges that they were starting to build under licence from Carter Gummow & Co. It is also possible that they wished to operate as consulting engineers themselves, and were not interested in being commercial agents for an overseas consultant, which is all that Waddell was offering them. The Monash Papers in the National Library of Australia contain much information from this period that we have not studied in detail.

With respect to the King River Bridge, Arthur Timmins's work diary for 28 February 1899 recorded: "Baxter & Saddler call re bridge over King River Tas. & arrange for us to make sketch for 2 tomorrow". The same day, Anderson cabled Waddell: "At what price can we tender deliver here f.o.b. first July single line Z[?] type Pratt 160 feet. Delay damages twenty pounds daily". He also wrote to Monash: "I have been making estimates etc for a bridge across the King River for the N. Mt Lyell Contract. B&S will accept if I give them a tender." In the following days, Arthur produced the sketch (above) showing the steel span and its timber approach spans. Anderson sent this to B&S together with sample drawings illustrating Waddell's American projects. He explained that the bridge would be similar to Waddell's Arkansas River Bridge, constructed for the KCP&G Railway, being of the deck type with the sleepers laid immediately on the top chords.

Waddell's reply, cabled on 3rd, was negative. He explained by letter that the Phoenix Bridge Co. had asked an "outrageous" price for quick delivery. In their defence, he commented that "the conditions were really prohibitory" and that "no bridge manufacturing concern in the United States today will take work under penalty." (Although, in respect of later projects he argued for just such a penalty.) Anderson commented that "The majority of Australian orders except for Government Works are executed in a hurried manner similar to this … and unless we can secure a locally made bridge; the river will have to be crossed by a set of timber bridges, though the district (Tasmania) is extremely wet and timber perishes rapidly there." (The original B&S proposal allowed for three timber truss spans, each of 50 feet, supported by intermediate piers.)

Monash's involvement

The main purpose of Monash's visit to Melbourne, from about 19 March to 12 April 1899, was to fulfil the requirements of the Militia for attendance at parades. However, he made good use of the opportunity to visit work on the Anderson Street Bridge, and to attend final negotiations and execution of the contract for the Fyansford Bridge. He spent much time with Saddler discussing B&S's contract for the North Lyell Railway, as well as the design, fabrication and construction of the King River Bridge. Before returning to Perth, he produced a report outlining his ideas for its fabrication and erection, advising that it be transported to site as individual elements, rather than as prefabricated sections; and that as much rivetting as possible be done in Melbourne. He suggested the assembly of the girders on "terra firma" and launching by means of an intermediate tower, rollers and cables. He also advised on the drafting of the specification.

Proposal for launching the bridge with the aid of a temporary trestle.

On Monash's return to Melbourne in July 1899 he shared with Anderson the routine of keeping an eye on fabrication and trial assembly of the bridge. The detailed account presented to B&S contains the following entries for this period:
"Conferring with Mr Timmins and Mr Ratcliffe re riveting up parts, and orders re same, also re having iron rivets, also re Customs duties &c., correspondence on these matters. Attending Mr Baxter re progress of works, also visits of inspection with him to see bridge partly erected in Otis yard."
"Several visits of inspection, during temporary erection of bridge, attending re alleged slackness of tension members and arranging for having proper camber. Attend Mr Sadler and Mr Clayton twice to explain and arrange these matters."

The detailed analysis of forces by Monash and Arthur Timmins was first mentioned in the latter's work diary on 16 August. Both worked on the task spasmodically until 8 September, sometimes for entire days, and sometimes outside normal working hours.

Note for engineers. The KRB trusses were many times statically indeterminate (upper figure in the graphical analysis. Monash used an approximate approach to the analysis of a "double Warren girder". He assumed the truss to be composed of two separate systems of members, each of which was statically determinate (second and third figures). This method has obvious weaknesses but, in view of the difficulty of analysing indeterminate structures at that time, was sanctioned in text books. (See e.g. Salmon 1938, still in print in 1953. Vol.2, p.14.) Even this simple method cost Monash and Arthur Timmins many days' work. In the bottom right hand corner of the drawing is a plan of the bracing (over half the span) and a related force diagram.

Intellectual property.

The detailed analysis was carried out on the instructions of the Copper Company's Engineer, Alfred Clayton, probably in anticipation of a call from Tasmanian "government engineers" led by W P Hales who, under the relevant Railway Act, were required to check the safety of the bridge. They seem to have met with a certain resistance, probably due to M&A's and B&S's sensitivity about intellectual property. After receiving the results of the analysis, Hales complained in October 1899 that he was still unable to check the strength of the bridge because the information supplied included neither the strength and quality of the steel, nor the cross-sectional dimensions of many of the members. His complaint was sent to the Copper Co which forwarded it to B&S, who passed it on to M&A. Their reply was:
"The following information is supplied to accompany the general drawing of the bridge, and the diagram of stresses issued in September '99.
The specification for the steelwork was as follows:
Ultimate strength 28 to 32 tons per sq. inch. [432 to 494 MPa.]
Elastic limit 14 tons per sq. inch. [216 MPa.]
Extension in an 8" test piece 20%.
Contraction in an 8" test piece 35%.
The material throughout was Siemens Martin Mild Steel, except for the rivets, which were wrought iron. There was no specification for the wrought iron in rivets, but a sample rivet, tested cold is supplied herewith.
The tabulation herewith shows the gross area of all the members. All rivets were ¾" [19mm] diameter, in the case of all tension members, there was a single leading rivet. Details of the joints showing rivets are not supplied herewith, but are available if absolutely necessary. It may be assumed, however, that ample shearing and bearing area in rivets has been provided.
Samples of the steel used, from which test pieces could be cut, can be supplied if required."

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