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Unbuilt Monier Arch Projects, page 3.

Tambo River Bridge, Monier Arch Alternative.
 Bruthen.

Longitudinal cross-section of the four-span Monier arch bridge. The hard rock is covered some 30 feet of alluvium. At left, a block abutment is supported on timber piles driven to rock. The three piers are taken down to rock. At right, the rock rises to road level and the right abutment is founded in rock.

Image: Reinforced Concrete & Monier Pipe Construction Co. Collection, University of Melbourne Archives.

On M&A's drawing the curve of the arches was indicated merely by sketching the 'springings' near the piers. The depth to bedrock is evident. Clear span is 90 feet (27.4m).

Overview.

In 1899 the Shire of Tambo called tenders for a timber truss bridge across the Tambo River at Bruthen. Monash & Anderson were obliged to enter a formal tender to build the bridge in timber, although their main purpose was to offer a Monier arch alternative. This appeared to them the clear favourite on technical and economic grounds. Unfortunately, there was confusion over funding at the time M&A were promoting their cause, and this was followed by a change of government.

These events might be explained by a newspaper clipping, retained in M&A's files, which refers to a "trick" played by the Tambo Shire (see timeline entry 1904/09/03 below), but the article does not specify the project involved.

The Public Works Department chiefs, Davidson and Catani, were sympathetic to Monier, though Davidson questioned the ability of one of the river banks to resist the thrust of an arch. M&A's proposals have intrinsic interest in the multiplicity of arches in Scheme 1 (shown above) and the introduction of a steel truss span in Scheme 2. They planned to use the well-known American bridge engineer J. A. L. Waddell as consultant for the steel span. The outcome was that they won a contract to build the bridge in timber. The Timeline tells the story reasonably concisely.

Timeline.

1899/10/03: A set of what appear to be Field Notes made during a preliminary reconnaissance.

1899/10/08: Estimates of Monier Design of four 90' spans. Total £7007. The details are similar to those for the estimate of 12th Oct. There is mention of a "bed of piles" 4 × 8 × 30ft = 960 l.f. @ 3/- = £150 per pier = £450, and a note that the price could be reduced by £447 by omitting the batters on the cutwaters.

1899/10/09: M&A to Mr C. R. Anderson, Shire Engineer, Bruthen. Can you meet JTNA who will be on a mission on Tuesday 10th to gather information preparatory to submitting a tender for the bridge?

1899/10/10: Age. The Shire of Tambo invites tenders for a timber truss bridge.

1899/10/10: Drawing. Pencil on tracing paper. Profile of bed and details of piers and foundations. Four rows of piles under one abutment. Clear span between springing points 90 ft. The three piers are spaced 95 ft centre-to-centre. The piers are 10 ft thick at the base and 5 ft thick at the top.

1899/10/10: JM to J. Best, again offering him a position as foreman. "We are just on the point of tendering for a large bridge job in Gippsland." JM encloses a sketch and asks for advice on costs. M&A propose four arch spans of 90 feet "nett". The abutments will be in the dry. Three piers will normally be in the water, but in summer the footings could be dry. The piers are to be on solid mass rubble concrete carried down to solid rock 23 ft, 26 ft and 33 ft respectively below the bed. The pier is to be 22 ft wide by 10 ft thick. The first 16 ft of the river bed is fine sand, perhaps with rocks and debris from recent floods; then "ordinary river alluvial", with possible veins of gravel and drift sand. The work seems to be very like some of the Queensland bridge foundations that Best put in for Baxter & Saddler.

1899/10/10: JTNA (Star Hotel, Bruthen) to JM. Re the call for tenders in The Age this-morning. They close on 17th. JTNA strongly recommends altering the Monier design "to reduce the width (along line of bridge) on the abutments to 7'-6" or even less and make the back two rows of piles rake to take line of thrust. The raking of piles makes no appreciable difference in the cost and was done at Anderson St."

1899/10/11: JTNA to JM. Telegram. "Monier will receive fair consideration recommend 92 feet spans."

1899/10/12: Estimate of Monier design (4 × 92 foot spans). £7466.

undated: List of expenses incurred by JTNA on his reconnaissance expedition from 10th to 13th. This shows he took his bicycle on the train to Bruthen, travelled by coach from the nearest station (Bairnsdale) and paid for horse hire and fodder, presumably to reach the site of the bridge. [Link.]

1899/10/13: JM to JTNA. JM returned from Geelong on Wednesday night. He was very busy but acted on JTNA's telegram and finished the design for 92 ft spans, "and consequentially raising of road level".

1899/10/14: JM notes: "All day in office on Tambo tenders".

1899/11/15: CRA to JTNA. Council is to send a deputation to the Minister of Public Works. The local MP, Mr Foster, is to be asked to bring all the influence he can to bear on the matter. It has been hinted that Mr Davidson does not altogether favor the Monier on account of the alluvium bank on one side of the river.

1899/10/15: [Sunday] "Into office with A. at 3 p.m. + complete Tambo tenders."

1899/10/15: Memo re the tender for the timber version, revealing that JTNA and JM did independent estimates of basic cost which produced almost identical figures, averaging £6670. To this was added £400 for local supervision (60 weeks at £6-13-4), £60 for head office expenses, £214 for contingencies (3%), and £700 for profit, to give a total of £8044.

1899/10/15: Computations for the Monier tender, total £7600. A note reads "Decided to tender at £7589."

1899/10/--: Letters, dated 14th, to Tambo Shire and CRA, enclosing a tender for the timber version of £8044 and making a formal alternative tender for the Monier design of £7589, accompanied by a preliminary specification. M&A note their Monier tender is much below their timber tender. They point out the durability, low maintenance costs, and architectural beauty of the Monier version. The road level will be 2'-6" higher than for the timber bridge. They have sent a copy to the Inspector General of Public Works. The arches are to have a clear span of 92 ft and a rise of 16'-6". The thickness at the crown will be 14", and that at the haunches 20". They are to have a top and bottom grid consisting of 3/8" bars in the longitudinal direction and ¼" lateral bars, both at 3" pitch. Up to RL 80.00 the foundations are to be 21' × 10' in plan. The piers start at 20 × 9 and narrow to 20 × 5 at springing level. The left abutment will have no less than 15 piles 14" in diameter. The spandrils are to be of concrete.

1899/10/17: CRA to M&A. Telegram, saying M&A's two tenders were the lowest and have been sent to the PWD.

1899/10/17: JTNA to CRA. Thanks for the wire. M&A are pretty sure they will now be successful. The documents have been sent to the PWD. JTNA has just dictated a short article which he hopes CRA can get in the O & T Times "as you thought you could". "I think it would do good, as it would remove any prejudice local people might have against the introduction of a new system of which they are ignorant. Hoping to have the pleasure of meeting you."

Strictly speaking, the official tender documents should have been sent to the PWD by the Shire but M&A, who were on good terms with the Board's senior officers, often sent copies direct to speed progress. The O & T Times is probably the Tambo and Orbost Times, based in Bruthen. An article entitled "The Introduction of an Important Invention - Monier concrete Work for Bridges" appeared in this paper on 28 October 1899. A copy of the original is in the UMA file.

1899/10/17: M&A to Catani. CRA has telegraphed that our tender is the lowest and has asked us to submit drawings and specification to you. They are enclosed.

1899/10/18: Calculations for timber coffer dams.

1899/10/18: M&A to F. M. Gummow & Co., describing the Tambo project. M&A learned that the PWD had £7000 available and the work was to be fully paid for by the PWD with Shire officers supervising only. Catani said he would have told them before if he had dreamt that Monier would have a chance, but M&A would have to tender legitimately for timber with Monier as an alternative. "We" went into the whole matter most carefully, spent a full week visiting the site, thoroughly paving the way for competition, and getting full particulars. The timber tender was cut very fine, while the Monier tender was on a satisfactory basis. The Monier design had 4 arches each of 92ft span and 16'-6" rise. The roadway width was 19'-6" clear. One abutment would be on solid rock. The other would be on driven piles, but on a steep bank. "… it is a most striking and significant demonstration in favour of Monier". Both tenders have been referred to the PWD. "If you see any way to support us in pressing for the adoption of our Monier tender, we trust you will do so. As soon as it has been accepted we will send you the usual data, so that you may give directions as to the Monier portion of the work."

1899/10/19: "Proposal for Brick Caissons" 12' outside diameter, 10'-6" internal. Six cylinders, of 30 ft average depth.

1899/10/19: Shire to M&A, thanking them for their tenders of £8044 and £7589. The next lowest tender was £8950. M&A's tenders have been sent to the PWD.

1899/10/28: Tambo and Orbost Times. JTNA's article on Monier construction. He notes that Bruthen is in the heart of "splendid forest country", but the advantages of Monier prevail nevertheless.

1899/10/31: JM to C. H. Evans, offering him the job as foreman. M&A were the lowest tenderers at Tambo, but the price is higher than the Department estimated, so it is now "fussing around to see if it can raise the extra money". This will probably take two months.

1899/11/03: JTNA to CRA. Treasury has advanced only £3000 and the PWD is evidently awaiting some action on the part of the Tambo Council. The bridge must be built in summer.

1899/11/03: JTNA to CRA. (Unofficial accompaniment to the letter above.) Catani says Tambo will be hung up indefinitely unless strong steps are taken to induce a further grant from the government. Catani thinks the best action would be a deputation from the Shire to the Minister. JTNA hopes CRA can induce the Council to do this.

1899/11/18: M&A to FMG&Co. Inter alia: nothing has been done re Tambo - "it transpires that only a third of the money has been voted … and Davidson is certainly very much to blame for allowing such a position to arise." But money should be available shortly "as one, at least, of the Cabinet, is vitally interested in the work being gone on with shortly".

1899/11/23: GF&Co to M&A, commiserating re Tambo and Wheeler's Bridge. "The workings of many Govt Departments is [sic] at times inexplicable."

1899/12/01: Shire of Tambo to M&A. The bridge project will not proceed.

1899/12/01: M&A to CRA. In view of the delay of seven weeks, and the defeat of the present administration, could we have our £200 deposit back?

1899/12/06: M&A to T. G. Stirling, Shire Secretary, Bruthen, thanking him for the return of the deposit and asking if he has any idea whether it might go ahead next year. Will fresh tenders be called?

1900/01/03: M&A to GF&Co. M&A are so busy, they do not feel much anxiety about "the result of the agitation of the Tambo Shire Council". They are sure they will get the job, and are happy for a couple of months' delay.

1900/02/12: M&A to CRA. They have heard that designs are being prepared for a timber bridge with spans of 75 feet and offer an alternative tender. The extra labour involved for CRA will be compensated by the fact that he will be spared "the anxiety and tedious labour involved in checking the contractor's work on a complicated timber structure, which is so much greater than the similar responsibility which falls on the engineer in connection with the simple masonry we provide."

1900/02/27: M&A to J. A. L. Waddell, Kansas, USA. Inter alia, M&A send details of their Monier design for Bruthen to see if Waddell can do it cheaper with steel or "composite" construction. M&A's estimate for the Monier work involved is £7600. (The whole bridge will cost about $37,500). They have provided about $20,000 for the foundations because of "the giant trees encountered in alluvial deposits". The combination which seems most likely to us is "a steel span of about 200 ft from the high bank across the deepest portion of the river (right hand side on plan) with two Monier arches on the shallow side, each about 85 ft span. This would eliminate the most expensive and difficult pier." The bridge is "an ordinary Highway Bridge and would have to carry about 8-ton dray loads, from heavy bullocks possibly a live load of about 80 lbs to the square foot."

Waddell was a renowned American designer of steel bridges and author of a text entitled De Pontibus. In August 1897 he wrote to Professor Kernot asking him to suggest local engineers who might represent him in Australia - though he wished to carry out all design work himself. M&A remained in touch with him until August 1901, mainly in connection with proposals for a bridge across Sydney Harbour.

1900/03/20: M&A to Stirling, putting forward the proposition made to CRA. [Entry 1900/02/12.]

1900/03/29: Waddell to M&A. Thanks for the information re the North Shore Bridge Sydney Competition. He will look at M&A's Tambo bridge layout.

1900/04/02: Estimate by a quantity surveyor for M&A's tender for the timber version. Total price £3294-13-4. Piles will be Ironbark or Yellow Box. All other timber will be Yellow Box.

1900/04/02: M&A to CRA. They regret he has left Tambo Shire, but are sure he will do better in Tasmania.

1900/04/07: M&A to Waddell. The Government has decided on a timber bridge for Bruthen.

1900/05/05: M&A to Catani. Having executed the contract for Tambo M&A will now go ahead with construction of the timber alternative.

1904/09/03: Argus. "The Tambo Shire Council yesterday tried to repeat a smart move which it played off in a transaction it had a few years ago with the Public Works department. The Council, it seems, induced the department to place a sum of money on the Estimates to cover the cost of a bridge. Next it persuaded the department to undertake the erection of the bridge. The works cost £1300 more than the amount placed on the Estimates, and of course the department had to find the extra sum. In the schedule of the Surplus Revenue Bill, now before Parliament, there is an item of £3000 for the construction of a bridge over the Tambo River at Swanreach. It is known that this bridge will cost between £4000 and £5000 to build and when the £3000 was provided in the Surplus Revenue Bill the idea was that the Shire Council should find the balance. Yesterday, however, a deputation awaited on the Minister for Public Works (Mr Cameron) and requested that the bridge should be made by the department. The excuse for the council's desire to be relieved of the work was that it had not available the services of a competent engineer to supervise the construction of such a large undertaking. The officers of the department remembered the previous experience. They informed Mr Cameron who told the delegates that owing to the reduced state of the staff the department could not comply with the request."

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Proposed Bridge at Daylesford
at Leggatt Street over Wombat Creek.

Longitudinal half section, half elevation. The rise of the arch is relatively high: 16 feet for a 75 foot span. The spandrels are of brick masonry.

Image: J. Thomas Collection.

Overview.

This project for an arch of 75 feet span to carry Leggatt St over Wombat Creek, includes an interesting comparison of a Monier culvert with an unreinforced concrete culvert designed for the same task. The descent of Leggatt St to the level of the old timber bridge involved steep gradients. To reduce these the Borough Engineer, Charles Devlin, proposed to increase the height (and thus the width) of the approach embankments and replace the bridge with a lengthy culvert. M&A showed that a Monier culvert would cost only £329 compared with £576 for Devlin's mass concrete culvert. However they pressed for adoption of a full Monier arch bridge (tender price £1100) which would provide a greater waterway in times of flood, while the greater cost would be balanced by a reduction in the volume of earthworks. Devlin was one of the Colony's older engineers, yet was enthusiastic to use Monier construction. The M&A records suggest that the project was delayed by proposals to form the lake on Wombat Flat. Two years later the old bridge was still being repaired.

Devlin is described in the Municipal Directory of Victoria for 1901 as "Clerk of Works" for the Borough. He was also Engineer for the Shire of Mount Franklin. Devlin's death was noted in The Age of 17 September 1906 which stated that he had been Borough Engineer of Daylesford since 1875.

Timeline.

1900/01/08: JM to JTNA. Inter alia, JM will call on Catani re the bridge at Daylesford.

1900/01/16: M&A to Devlin. "The Public Works Department, through Mr Catani, have notified us that your Borough is contemplating the re-erection of a bridge at Sailor's Gully over the Wombat Creek …" Catani says the site is very suitable to a Monier arch which will allow raising of the road level. Please send a section of the creek and details of foundation conditions. [M&A did not gain the contract for the Sailor's Gully project.]

1900/01/17: Devlin to M&A. "As one of the oldest identities of road and bridge construction in this Colony, I am quite taken with the 'Monier Construction'." Devlin will supply the requirements later on. [Dated 14th, but postmarked 17th.]

1900/01/17: Devlin to M&A. "Herewith find a tracing of longitudinal section of approaches to Leggatt St Bridge across Wombat Ck, Daylesford. The drawings that were prepared were for a 60 feet long in the barrel of a concrete culvert and 10 feet wide by 8 ft to intrados of Arch. Council have £600 set down on Government Estimates conditionally that another similar sum is expended as the earthwork is heavy in order to reduce the steepness. I reckon that it will cost about £1500 with other minor works. This Culvert alone I would estimate about £400. So that if one span under the Monier method were carried out it would save considerable filling. The present old structure has four openings at 25 feet. I am quite in favor of the New Method having seen the bridge across the Yarra. In haste."

1900/01/29: JM notes: "At 5.30 am to Daylesford, thence to Allendale …"

1900/01/29: JM to JTNA. "I met McLeod, Daylesford Town Clerk (in lieu of Mr Devlin who was busy at a Shire meeting at 11 this morning), and went straight to the site of Leggatt's bridge and made all the observations and measurements necessary for a final design and tender. After lunch I made full enquiries as to carting, broken stone, sand and gravel, and then saw Mr McLeod again probing the financial situation and prospects. Devlin has apparently worked up some local enthusiasm for Monier. I left a set of photographs for the edification of the Councillors. McLeod says that the last year's vote for the Government moiety was £400, but has lapsed and they have the promise that it will be revoted as £600. I judge that the Monier scheme if in the region of £1200 to £1500 is sure to be recommended. I am sending direct to Arthur [AGT] the principal of my sketches and instruction to rough out a design."

1900/01/29: Levels for "Wombat Creek Bridge".

1900/01/29: Drawing. Pencil on tracing paper, showing a small locality plan of Wombat Creek and an elevation of the existing timber bridge and profile of the gully. The waterway appears as a very small channel with the disparaging designation "Wombat Creek !!!" A further note states: "The whole area has been sluiced over, and rock bared all over - schistoze and slate fairly hard where exposed."

1900/01/29: JM to AGT, telling him to get the sections at Daylesford and, if he has time, rough out a design. AGT should endeavour to fit in one of the 75 ft spans of Wheeler's Bridge. Finally, if time permits, he should rough out a design [drawing] to quarter scale.

1900/01/30: McLeod to JM, thanking him for a photograph which he showed to Council when they visited the site. Council will let M&A tender for a Monier bridge.

1900/02/02: Computations showing that 3797 cubic yards of earth fill will be saved if the arch proposal is adopted.

1900/02/06: Devlin to M&A. He has received an invitation from W. H. Gore [Engineer for Creswick] to have a look at the Wheeler's Bridge "before the planking is put on". He wants, if possible, M&A to be there "to have the Monier Method explained".

1900/02/08: M&A to Gore. Inter alia: "We learn incidentally that you have been in communication with Mr Devlin, and we thank you for your kind offices in our behalf."

undated: Estimate for the Monier arch, based on experience with Wheeler's bridge. £1250.

1900/02/08: Estimate for a Monier Culvert. £329.

1900/02/08: "Quantities for Mr Devlin's culvert." £576.

1900/02/12,15: "Final Estimate …" £934-8-0 plus profit £200 =£1134-8-0. "Tender as a first approximation with a 10% saving[?] clause £1100."

1900/02/21: M&A to Devlin. M&A propose an arch with concrete spandrel filling and wing walls, and a span of 75ft. They argue this is cheaper than "the proposed culvert" plus filling, and it provides more waterway. (The culvert designed by Devlin is 10 ft wide. Devlin says it will be 60ft long, but in view of the height of the embankment M&A think he must mean 90ft.) M&A estimate Devlin's culvert plus earthworks etc at £1000 and a Monier arch at £1100. Alternatively, M&A could build a Monier culvert 20ft wide for about £350 - leaving the earthworks for local contractors. This would halve the depth of flow during floods.

Cross-section looking along the line of the creek, showing the road embankment stretching across it. The embankment is penetrated by a small culvert whose form is like one half of a cylinder that has been split longitudinally. The edges of the half-cylinder rest on the bed of the creek.

Unreinforced concrete culvert as designed by Devlin.

Cross-section looking along the line of the creek, showing the road embankment stretching across it. The embankment is penetrated by a culvert formed from a wide Monier arch. Its profile is a flat parabola. Its springings are founded in the banks of the creek.

Monier arch as designed by M&A.

Above: Schematic comparison of Devlin's and M&A's proposals.
The arch provides more waterway to cope with floods, and requires less earthwork.

1900/02/22: Devlin to M&A acknowledging receipt of the design and explanatory notes. He is convinced of the merits of the Monier Method and will do his best to convince Council. However, some councillors want to make a lake of Wombat Flat utilising the embankment and making a byewash. There are many old bridges in "senile decay" so he will keep M&A informed.

1900/03/22: JM notes: "To Creswick, Lawrence, Kingston and Daylesford".

1900/03/24: JM to Devlin, hoping to see him at the test of Wheeler's Bridge on 30th.

1900/05/29: Devlin to M&A, enclosing a clipping "Government Grant" on the bad state of bridges in the Shire. This mentions "it is said that" the government prefers Monier bridges, as timber bridges are very expensive to maintain and replace. Devlin remarks that "The Leggatt St Bridge is held over until the revote".

1900/09/06: M&A to Devlin. They note that money has been allocated for bridges at Wombat Creek (£1200) and Jim Crow Creek (£2000). They ask if they can negotiate [and/or] tender.

1901/04/11: Devlin to M&A. Nothing has been done yet in relation to the Leggat St Bridge.

1900/07/12: M&A to GF&Co. Inter alia, Mr Davidson has recommended a 60 ft Monier arch near Daylesford.

1901/07/16: Argus. The whole Daylesford Council is to consider "Leggatt's Bridge" and other works.

1901/07/26: Devlin to M&A. There is still nothing yet re Leggatt.

1901/11/20: Devlin to M&A. There is no hope of alteration to Leggatt St re the decking. [M&A must have offered to re-deck the old timber bridge with Monier slabs.]

1902/??/21: Devlin to M&A. Their tender for re-decking of the Leggatt St Bridge and other repairs was not accepted. Council is undecided as to whether the grant is to be taken advantage of. The whole matter is held over in the meantime.

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Proposed Bridge at Steiglitz
on the Meredith-Steiglitz Road, over the Moorabool River.

This proposal is included because it illustrates the adverse influence of a councillor who had read his engineering journals. The proposal to use a Monier arch initially came from the engineer who oversaw the construction of the Fyansford Bridge, A. L. Campbell. He was engineer for both the Corio and Meredith Shires and, before his relationship with M&A deteriorated, he was apparently on the lookout for opportunities for them to apply the new technology.

1998/02/06: ALC to M&A. "Dear Anderson, I have found a place in the Meredith Shire where a Monier Bridge would suit." ALC requests a price for Monier only and says he will do the rest. He provides a sketch profile of the creek which suggests a span of 60 ft. He wants 16'-6" clear width. A price of £190 has been noted in pencil on ALC's letter.

1899/07/06: Geelong Advertiser. "A Dangerous Road." [Re the Steiglitz Bridge.]

1900/03/02: Geelong Advertiser. Steiglitz Road Bridge (over the Moorabool River). Meredith Shire Council is to decide whether it should be in wood or Monier.

1900/03/02: Geelong Advertiser. The Shire calls alternate tenders for wood or Monier.

1900/03/02: M&A to ALC. "Just to hand your telegram re above. The time allowed for tendering is very short for us to take part. If we can possibly manage it one of us will be down at Geelong on Monday next and would like to meet you at your office."

1900/03/05: M&A to W. Kelly, 78 Fyans St., Geelong. Re yours 3rd inst., re Meredith Bridge. M&A need more information. JM is today at Geelong making enquiries, and will give you a price tomorrow morning. JM will call on you if time permits.

Kelly was a prospective general contractor who would have had to subcontract the Monier arch ring to M&A, as they controlled Victorian rights to the patent.

1900/03/06: M&A to Kelly. M&A's price for the Monier work alone, included in Mr Campbell's schedule, item No.8, is £220. This assumes Kelly will supply 43 cu yds of sand, cartage, and use of some plant.

1900/03/06: M&A to Shire of Meredith. Tender prices for Steiglitz are: (a) for the whole job; £596-11-02, (b) for the Monier alone; £358. These are based on a schedule of rates, as they have had no chance to inspect the site.

1900/03/08: Geelong Advertiser. "The Steiglitz Bridge." [Report of Council meeting.] The estimated cost of a Monier bridge is £500. The Colony government will contribute only £150, so the council would have to pay £400 or over. Cr Molesworthy said he had read in engineering journals that engineers questioned the durability of iron in concrete. Council resolved to have a timber bridge.

I am fairly sure that the figure printed in the newspaper is £500, representing a large drop from £596-11-02, but it could be £600. The latter figure fits in better with a council contribution of £400+.

Durability of iron in concrete. Molesworthy's statement is quite correct. It was being realised that, provided the concrete was of good quality and the reinforcing bars were embedded to an adequate depth, the alkaline nature of concrete would provide long-term protection against rusting of iron or steel. However there had been many cases where the quality of the concrete or the amount of cover had been inadequate and these confused the issue. Time has shown that the cover commonly provided in M&A's era was insufficient over the long-term. Many of their bridges, the arches in particular, have required remedial work. This has normally been the spraying of a fresh surface coat of mortar from a pneumatic gun.

1900/03/09: M&A to Shire of Meredith. We gather from the press that our tender for Steiglitz was not accepted. May we have our £30 deposit back?

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Proposed Bridge at Pewley Hill
over Deep Creek.

Longitudinal half elevation, half cross-section. The arch has a conventional profile, and masonry spandrels. The abutment blocks are unusually deep, extending to bedrock.

Image: J. Thomas Collection.

Overview.

The correspondence associated with this project throws light on the practical considerations which governed the cost and suitability of Monier construction. It also demonstrates the effect which problems on the Wheeler's Bridge project had on the opinion of the local engineer, W. H. Gore and that by 1905 JM felt hopeful enough to approach Gore for further work.

Timeline.

1900/02/23: W. H. Gore [Shire Engineer, Creswick] to M&A, enclosing a cross-section of Deep Creek at Pewley Hill and details of "local circumstances affecting cost". There is a hotel within 30 chains of the site and another within one mile. It is nearly all downhill from the railway station to the site. Stone, sand and "piles for centering" can be obtained locally.

An important factor in Monier construction was transport of cement by rail from Melbourne or Geelong to the local railway station, and from there by horse or bullock cart to the bridge site.

1900/02/26: M&A to Gore. Thanks for yours of 23rd giving details of the bridge at Pewley Hill over Deep Ck.

1900/03/07: M&A to Gore. We can give you a lower road level to reduce embankment costs. Instead of 101.55 we suggest 98.00. This still makes good provision for floods. If the approaches are kept at this level, it will give an embankment length of not greater than 7.5 chains. The embankment will nowhere be more than 3ft above the existing approaches. M&A propose one span of 60ft, with a 9 ft rise, which would thus be similar to the Fyansford side spans. [This was probably to permit re-use of the centering built for the Fyansford project.] The width of arch would be 21ft. The foundations would go down to 76.2 ft at which level they would be 14ft wide. [The 76.2 must be a survey level relative to a datum, not depth from surface.] The spandrels would be in concrete as at Wheeler's Bridge. M&A suggest a timber handrail for economy. For the bridge and approaches, the cost would be £1150 to £1200. The arch thickness would average 12". As the load is very light M&A propose only one grid.

1900/03/??: Drawing bearing the handwritten inscription: "Monier Bridge. Deep Creek at Pewley Hill, March 1900".

1905/02/08: JM to Gore. JM notices that fresh tenders are to be called for the Deep Creek Bridge. Does this mean that the quotations received were considered too high? What about a chance to offer Monier? Much Monier work has been done in Victoria and NSW since the erection of Wheeler's Bridge "and however unsatisfactory that work may have proved in certain respects, there is not a breath of criticism fairly possible in connection with the Monier arches. Bridge construction in Monier work has developed in many directions and I feel sure I could submit proposals and quotations which would save you a substantial amount of money over ordinary construction, besides giving permanency."

There are many 'Deep Creeks' in Australia and each one crosses several roads, so I cannot be certain that the Deep Creek project referred to in 1905 is the the same one discussed in 1900. However, it was not unusual for several years to elapse while such projects were considered. If the supposition is correct then the Deep Creek referred to must have formed the boundary between the former Shires of Creswick and Mount Franklin and according to Mr N. Darwin is probably the one which rises just above Eganstown and flows north. Mrs Karyn McColl advises that Pewley Hill is a topographical feature, to the north of Mt Kooroocheang, where her family (Smith's and Gervasoni's) have lived for generations. The Smiths would have been in residence in 1900-05.

1905/02/11: Gore to M&A. Re yours of 8th, tenders are being called again for 2nd March, but Mount Franklin Shire is not in favour of spending much money. Timber will win.

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Proposed Bridge at Charlton
to carry the Calder Highway over the Avoca River.

Schematic longitudinal elevation of a three-span Monier arch bridge. A description is provided in the text below.

Sketch: Reinforced Concrete & Monier Pipe Construction Co. Collection, University of Melbourne Archives.

Overview.

This bridge was proposed for the Shire of Charlton which had E. Gilchrist as engineer. The layout of the spans is reminiscent of Fyansford which had a central span of 100 ft and side spans of about 60 ft. [Fyansford story, layout.] However, the central arch is given a high ratio of rise to span, with its springings much lower than those of the side arches, bringing its outward thrust almost directly to the ground. Its haunches are shown filled with mass concrete to the same level as the top of the piers. In the finished structure the arrangement has the disadvantage that the thrusts from the outer arches do not balance with those of the inner arch in either magnitude or level. The shape of the piers reflects measures taken to cope with this. The objective may have been to simplify construction. In a bridge with identical arched spans, the piers must either be made thick enough to resist the thrust of a single arch during construction, or they must be propped sideways. In this case the central arch would have been immediately self-supporting without the need for such measures. On the other hand the piers shown in the drawing seem extremely thick.

Timeline.

1900/03/08: Rough preliminary estimate:

basic cost£1277
supervision and contingencies 20%256
profit250
 £1783

1900/03/10: M&A to Gilchrist. Working on very scanty information and having had no meeting with Gilchrist, M&A can give only a very rough idea. As Gilchrist could not answer the standard questionnaire in time for M&A to give a full quote by 15th, the proposal is based on average conditions. In every case in competition with steel, Monier has beaten the steel price by 50%. With steel £5 per ton dearer than twelve months ago, and still rising, the difference is liable to be more marked. In competition with timber, Monier requires no maintenance. For spans up to 30 ft, Monier is about twice the price of timber, but for spans of 60 ft and over, where good foundations are available, Monier is cheaper. M&A are willing to modify their design. If it will be competing with timber rather than with iron, they will provide a less substantial, less architectural design. They have aimed to provide a 155-foot clear waterway, so the bridge is 190 ft long overall. The site is awkward as there is a long stretch of low ground on the left hand side of the cross-section, which will be covered by high floods. M&A therefore suggest raising the road level from RL 40.00 to 42.00. They suggest a central span of 75 ft, and side spans of 40 ft. The crowns of all the arches will be at the same level. The rises will be 16'-6" and 6 ft respectively. The thicknesses of the long span will be 14" to 12", and that of the short spans 11" to 9". There will be a double grid [of reinforcement] in the central span and a single one in the outer spans. The road will have a clear width of 24 ft. It would be possible to have 20-foot-wide arches with outrigged footpaths, but M&A do not recommend this. The substructure of abutments and piers, the haunch fillings and the spandrels (where greater than 3ft thick) are to be of lime concrete. Skewbacks and walls less than 2ft thick are to be of 7 to 1 cement concrete. M&A have assumed suitable foundations not more than 5ft below ground surface. The pressure will be 2 tons per sq ft. Piers and abutments will be 7 ft thick at the springing, widening out below to accommodate the thrust. At a rough estimate, the cost will be £2500. If there is a reasonable prospect that the project will go ahead someone will visit Charlton at M&A's expense to investigate and prepare drawings, specifications, etc.

1900/03/20: Gilchrist to M&A, thanking them for the photographs. Council will apply to the government for a grant. Their decision will depend on that. All Councillors were impressed with papers etc.

1900/11/02: Gilchrist to JM. Seeing as Monier is coming out cheapest … would you give us a design? Here is the longitudinal profile of the site.

1905/02/08: M&A to Shire Engineer, Charlton. Is there any news of the arch bridge negotiated with Gilchrist? [Gilchrist has left the job.]