More on sus bridge



In 1852 a new pedestrian Suspension Bridge with an innovative design was completed in Chester to provide a link between a speculative up-market housing development and the city. This was the Queen's Park suspension bridge, but it was not the first such bridge in Chester.

A few years earlier, in October 1849, the “Civil Engineer and Architect's Journal” had reported on the construction of “Novel Suspension Bridge” at Chester. This crossed “The Dingle” between the embankment of the Grosvenor Bridge and Curzon Park where new housing was being developed by Earl Howe. The new bridge was of a unique design as it dispensed with piers and suspension rods above the level of the deck which formed the walkway. The deck of the bridge was instead supported on “chains” made-up of 15-foot long wrought-iron rods which had an eye at each end and were joined together. One end of these chains was secured to an abutment at the Grosvenor Road end, but at the Curzon Park end an extension of the the chains passed around a “strong grooved barrel” and dropped into a pit, where the chains supported a cast-iron plate loaded with a large quantity of heavy masonry. The effect of this movable weight was to keep the bridge under tension while allowing for expansion and contraction as the temperature varied. This “self-adjusting” bridge was reported far and wide, including in the American press.

The 1852 Bridge
The bridge of 1852 was a slightly more standard design (although as explained below not a true suspension bridge) and its construction to link another new suburb to the city, that of Queen's Park, may well have been prompted by the Curzon Park bridge. Queen's Park was being developed, since 1851, by Enoch Gerrard, a Chester businessman. He no-doubt hoped that the convenience of a footbridge across the Dee would encourage people to move. It also gave them a way to avoid passing the noxious skinner's yard which lay between Queen's Park and the Handbridge end of the Old Dee Bridge. The original Queen's Park Bridge cost £850. Despite the bridge, the residential development of Queen’s Park was slow and only four villas and two semi-detached pairs had been built by 1873. By 1910 the total had still reached only 17, although a further 10 houses had been built on St. George's Crescent to the south. The experience there, and at Curzon Park, suggests that the demand for exclusive property in Chester was smaller than the amount of sites available.

A simple suspension bridge is but one of several sorts of bridges. Among others are stone arches as can been seen at the Old Dee Bridge and the Grosvenor Bridge. Chester also has several truss-bridges, of which one was Robert Stephenson's somewhat experimental cast-iron railway bridge over the Dee which famously failed in 1847. The Old Dee Bridge is medieval, the Grosvenor Bridge was built between 1827 and 1833 to a design which could allow tall-ships to pass, and Stephenson's railway bridge of 1846 is much lower, showing perhaps how the fortunes of the port of Chester had changed over a short span of years.

In arches the stone is compressed by the weight of the structure above to lock it firmly into place and the bridge needs to be supported by temporary “false-work” until the arch is complete whereas with most suspension bridges the deck of the bridge hangs from chains or cables and is simpler to put in place. Early stone arches used a semi-circular form which is not the most efficient and thus tend to be bulky. A good example of such a massive arch can be seen in the Norman north transept of the Cathedral. However the Gothic (pointed) arch replaced them. The ideal shape of an arch is actually a catenary curve, which is close to a parabola and is the shape that a chain forms when hanging between to posts. The application of the catenary to the construction of arches is often attributed to Robert Hooke, whose "true mathematical and mechanical form" in the context of the rebuilding of St Paul's Cathedral alluded to a catenary. However there are older known arches which approximate to a catenary.

In a catenary suspension system the weight of the flexible chain is carried by tension along it, and inverting this produces the most efficient arch with a minimum tendency for the arch to buckle or “burst”. Such a near-parabolic curve within pointed Gothic arches forms the “thrust-line” along which the forces are borne. Provided that the thrust line stays within the structure then as a rough rule-of-thumb the structure should be stable. Much early architecture would have been built without the advantages of modern mathematics and early engineers would have based designs on what had worked before. There was the possibility of making models, but these were poorly understood. The weight of a structure increases as the cube of its size whereas the failure stress grows as the square. The “scale” model of the Grosvenor Bridge on Castle Drive is actually a bit of a con-trick as it is so much smaller than the actual bridge that it proves nothing about the stability of the real bridge.

No doubt the earliest suspension bridges were of rope or vines and formed the sort of “jungle bridge” which spanned The Dingle prior to replacement. However the Tibetan siddha and bridge-builder Thang Tong Gyalpo originated the use of iron chains in his version of simple suspension bridges. In 1433, Gyalpo built eight bridges in eastern Bhutan, at least one of which (Chushul Chakzam) survived into modern times. According to some sources the “first” chain bridge in the west was the Winch Bridge, built around 1741 across the Tees in North-eastern England, however bridge-enthusiasts seem remarkably disputatious about who did what first.

Suspension bridges are sometimes notoriously flexible. This makes some sense as tensions in the bridge will tend to redistribute with expansion and movement of loads. A good example of a chain bridge can be seen crossing the river Dee just above Llangollen, but the original Queen's Park bridge was not a pure, simple chain suspension bridge, rather it was a sort of hybrid with elements of the “cable-stayed” bridge. The “hangers” on the bridge were angled and the formal name is a “double cantilever”. Many early suspension bridges were only intended to be used for foot traffic because other vehicles, especially trains, would impose large and rapidly moving shock and point loads on the structure.

Dredge's design


The figure on the right shows three different types of bridge. In a conventional suspension bridge (top) the deck is supported on vertical hangers connected to a catenary between the towers. The suspension cables are free to move on bearings at the top of the towers and must be anchored at each end of the bridge, since any load applied to the bridge is transformed into tension in these main cables. The main cables continue beyond the pillars to deck-level supports, and further continue to connections with anchors in the ground. In a stayed cable bridge (bottom) there is no catenary and a distinctive feature are the cables or stays, which run directly from the tower to the deck, normally forming a fan-like pattern. The towers carry the entire weight of the bridge meaning that ground anchors are not required. Dredge's design is a hybrid between the two.

The mathematical analysis of the Dredge type of bridge is rather complex, and "tuning" of the bridge to prevent vibration would have been difficult. Perhaps little mathematics was used in the design of the Queen's Park bridge as the bridge was well-known for “dancing about”. In September 1859, “The Builder” described it thus:


 * “To Queen's Park there is a foot-bridge, on Dredge's suspension principle, east of St John's Church...It is exceedingly slight and sways and undulates by the tread of the crowds passing over it on Sundays, in what appears to be a dangerous manner”.

[https://en.wikipedia.org/wiki/James_Dredge_Sr. James Dredge] (1794-1863) was a brewer from Bath who, in had patented (No 7120, taken out on 14 December 1836) the “taper principle” and had built the Victoria Bridge (1832) in that city to carry his beer. Although many books state that this was his first bridge it was not. The Victoria Bridge is the earliest bridge of his which is still standing following restorations. His first bridge was apparently at Balloch Ferry near Loch Lomond, and was later replaced by another suspension bridge. His other surviving bridges are a bridge at Oich in Invernesshire, two foot-bridges in the town of Inverness and a very attractive foot-bridge over the Kennet and Avon Canal near Pewsey. Some writers suggest that he was a competitor for the design of the Clifton suspension bridge, which Brunel won. He offered to replace the damaged Menai Bridge free of charge having calculated that his taper chain would use much less iron, and the scrap value of the old bridge would more than pay for the replacement. However his offer was considered too good to be true, and it wasn't taken up.

The “taper” refers to the fact that that suspension chains are thicker toward the top of the piers where they carry more tension, something which can be seen in the photographs of the first Queen's Park bridge. According to Dredge, the advantage of the taper system is that the resulting design is cheaper to build than a conventional suspension bridge of the period because it uses less of the expensive wrought iron and is quicker to build (steel had not yet been invented). In theory a Dredge bridge can be cut through the middle and will not collapse due to the cantilever design. Dredge never tried that experiment, but he did load model bridges with what he could conveniently find in his brewery – beer, horses, sacks of malt and men.

Dredge's bridge designs were however surrounded by intense controversy and pages of mathematical discussion appeared in the engineering journals of the time. This was a time when bridge design using new materials and innovative structures was to a large part experimental, and there has been several notable accidents, including the Dee Bridge disaster of 1847. Significantly, there were several incidents with suspension bridges including the Broughton Suspension Bridge (1831), the Yarmouth Suspenion Bridge (1845), Angers Bridge (1850) and Wheeling (1854). Some of these involved resonance, such as by troops marching in step, others were due to over-loading. It is for this reason that marching soldiers are expected to break step when crossing a suspension bridge. Unfortunately if a bridge does start to oscillate this can cause those upon it to walk in step making the problem worse.

Several of Dredge's bridges collapsed, including a few in India. In October 1846 news had arrived from India that:


 * “A bridge on Mr. Dredge's principle, which was put up a short time since across the Kubudduck River, near Jessore, has fallen. On testing, the bridge was found to be weak even though 'guaranteed by Mr. Dredge to stand any traffic' and before its use could be restricted, 'some grand festival took place on the water, to witness which, a crowd of natives rushed on the bridge, nearly filling the platform, and after a few minutes it gave way, and drowned nearly one hundred and fifty of them.”

The Royal Engineers in India carried out extensive testing of the Dredge designs including one which involved loading the bridge with a twenty-four pounder artillery piece (~three tons) drawn by an elephant (~four tons). This was an eminently sensible test as elephants were used to transport artillery, including the rather ancient 24-pounder naval guns which were re-purposed for use on land, but it is only the weight of about 100 people.



Dredge went bankrupt in 1849, but appears to have still been building bridges and mentions the Dee bridge in his literature of 1855 by which time his 1836 patent had expired. While his bridges were still collapsing Thomas Penson, the noted Chester architect was still trying to avoid building them, including one at Caerhowel in 1854 where his objections were over-ruled and a Dredge-type bridge constructed. Penson was proved right as the Dredge bridge at Caerhowel collapsed in 1858 and Penson got his own design built instead - it is still standing.

More concerns
The first Queen's Park bridge was the subject of some further concerns in August 1877 following the collapse in June of the Widcombe “Suspension” Bridge in Bath – which was not actually a typical suspension bridge, but a "bowstring" bridge. The cause was an influx of tourists who crowded onto the bridge, rushing to see an agricultural show. Despite it being a quite different type of bridge this caused the subject of the Chester bridge to be raised once again, as reported in “The Engineer”:


 * "The Grosvenor and Queen's Parks, Chester, are united by a suspension bridge for foot passengers, of considerable span. This bridge requires careful examination, if the Bath catastrophe is not to be repeated. When there are regattas on the river it is almost impossible to keep the crowd off. The Board of Trade ought certainly to have this bridge examined and reported upon. If it is all right, well and good; no harm will have been done by our word of warning. If it is found to be as dangerous as we assume it to be, then our advice may prevent the recurrence of a very grave calamity."

In fact, the matter had already been discussed in Chester, but the bridge must have been notorious for its shaking as the debate in Chester as to whether the bridge should be surveyed by an engineer was reported in many small newspapers including the somewhat obscure Cambrian News and Merionethshire Standard (20th July 1877).

“The Engineer” also stated the following about the Chester bridge:


 * “The main chains consist of ¾ inch round rods with eyes turned-up and nominally welded, on the ends, which are united by transverse pins. The roadway has no vertical or lateral stiffness, and sways in a high wind. A policeman is kept patrolling it to prevent persons from standing on it.”

According to Chester historian Thomas Hughes, author of “The Stranger's Handbook to Chester”:


 * "It was a pretty object in the landscape. Though of such spider-like construction, its capabilities and strength have been fully tested"

We know nothing of the "tests" mentioned by Hughes, although they may have been little more than the observation that “many have crossed it”. The tests almost certainly did not involve elephants.

One myth which sprang up about the suspension bridge was that its construction was brought about by the “Fenian Assault” on Chester. According to this myth, of which several versions exist, the bridge was built so that troops could be rushed into the city of Chester from their garrisons on the opposite bank given that the Republicans had taken the Old Dee Bridge. There is no truth to this story – the “Assault” was in 1867, long after the bridge had been built. In addition the garrisoning of troops on the south bank of the river does not appear to have happened until much later.

The 1923 Bridge
There were several attempts to replace the original bridge, but these seem largely to have been concerned with convenience rather than with safety. In one, a new, "high-level" bridge “for carriages” was proposed from St Johns churchyard to Queen's Park. Although the days of the original bridge were said to be numbered, this 1895 idea went nowhere. The next attempt to change things was a 1902 proposal to extend the bridge so that it crossed Lower Green Street to meet the steps to St John's half-way down to The Groves. Once again this went nowhere.

The Queen's Park Suspension Bridge had been privately funded and maintained. When Chester Corporation accepted the responsibility for this bridge in the early 1920s, they at once decided to demolish it, something which had been expected for many years. Demolition took place in August 1922, and a new bridge took its place. It is often said that the new bridge was constructed to the design of Mr Charles Greenwood, City Engineer and Surveyor. This, although frequently repeated, is either untrue or Greenwood's input was very minor. The Chester bridge bears a strong resemblance to the Porthill Bridge in Shrewsbury which was in fact built earlier in the same year by the same firm: [https://en.wikipedia.org/wiki/David_Rowell_%26_Co. David Rowell & Co], a company based in Westminster, London. Rowell & Co. fabricated wrought iron and wire rope, built suspension footbridges, and structural steel frame buildings. They were established in 1855 and closed in 1970. They were well-known for their ready-made steel bridges which were exported in kit form all over the world, including to such far-flung places as Goose Green in the Falkland Islands and Arapuni in New Zealand. Many of their bridges have a characteristic design with a strong resemblance to the Queen's Park bridge and while a few are designed to carry limited traffic the vast majority are foot-bridges.

Gallery of the new bridge
The designer of the new Queen's Park bridge was actually named as William Thomas Edward Barker, an engineer who frequently worked with Rowell & Co. He had joined the company as a draughtsman in 1901, and was for many years chief engineer and manager for the firm. The new bridge cost £5,650 (Porthill cost £2,600). Greenwood was possibly only involved with the decorative details. The contractors for the foundations and masonly work was W. H. Brocklesby of Birkenhead. It spans 277 feet (84 m), and is supported on vertical hangers from two 2.75-inch (70 mm) diameter locked-coil steel cables, each capable of carrying up to 340 tons. It is founded on the north side on a 230-ton concrete block, and on the south side by anchoring into the sandstone bedrock. It is a more or less standard suspension bridge with the deck simply hung from the cables.

Greenwood had originally qualified as a barrister and eventually, in 1949, became the President of the Institution of Municipal Engineers. Greenwood had major plans for the redevelopment of the area around the bridge. He wanted to demolish all the houses fronting onto the River Dee just upstream of it and carry Grosvenor Park down to the bank (with an outdoor swimming pool). These were not his only plans for Chester. In 1945 he presented a redevelopment plan which attempted to reconcile economic and cultural considerations. This would have a major impact on the later development of Chester. As well as extensive council offices and a replacement for the Victorian public market, which no longer complied with hygiene regulations, the plan included a neo-Georgian civic centre with a new central library, a museum and art gallery, and a concert hall. A scheme based on Greenwood's plan was approved by the government in 1952 but, perhaps fotunately, not put into effect. His extensive “Northgate Scheme” also proposed to route the inner ring-round up King Street and out through a rebuilt Northgate. The possible demolition of properties in King Street blighted the area for years, until parts of the plan were scrapped in favour of a new gate (St Martin's) through the Walls.

Decorative shields
From its opening the 1923 bridge was decorated with large and bold representations of the supposed shields of the Norman Earls of Chester. In fact during the time of the first few Earls heraldry was not particularly developed and the "earlier" shields most probably were retrospectively assigned. These so-called "attributed arms" are Western European coats of arms given retrospectively to persons real or fictitious who died before the start of the age of heraldry in the latter half of the 12th century and before arms were made inheritable by Richard I during the lifetime of Ranulf de Blondeville. There is general agreement about the specific symbols associated with the various Earls but some of the ones on the bridge appear to be wrong: the arms of Ranulf de Meschines and Ranulf de Gernons have been switched around, and one is the wrong colour. However by the time of the latter earls the age of heraldry was well under way, and the arms of Ranulf de Blondeville are still in use to this day.



The photographs which show the opening of the new bridge in 1923 are monochrome but it is just possible to make out the names of the Earls in their correct places and the colours appear to have originally been correct.



The shields had become rather weather-beaten over the years, and were impressively restored by David Kynaston in 2012/13. Cast out of lead, broken and missing parts were repaired. The shields were fully repainted and finished in 23 1/2 carat gold leaf. Unfortunately older records shows Ranulf de Meschines as having a red lion on a gold field and Ranulph De Gernon having a white (silver) lion on a red field. The correct order and tinctures are shown below:

Gallery of arms
The restorer was somewhat dumb-founded when the error was pointed out, but it was hardly his fault given that he had been given detailed instructions. Elsewhere in Chester, in Grosvenor Park and in the Town Hall the arms of the Earls are correctly displayed. In many ways the swap-around is quite apt as Ranulph de Gernons was notorious during his lifetime for changing sides during the civil war known as "The Anarchy", and does not seem to have given-up!

Origins of the symbols


There has been much ink spilt on the question of when heraldry became commonplace in England. It is generally accepted that there is little of what could be called "heraldry" in the Bayeux Tapestry. There are emblems and patterns shown on some of the shields, but these may be decorative as it appears that the same knights bear different shields in some of the scenes depicted. One might assume that if heraldry could have been used to identify particular individuals it would have been used. There has been some discussion of whether Hugh of Avranches actually used the symbol of a wolf as depicted by various authors including Daniel King, but it is now generally accepted that this use is a later attribution. It is just possible that Hugh may have used the symbol of a lion which were originally called leopards ("lupars" in early Norman English).

The earliest known decorated shield which fits the description of a heraldic shield is that said to have been given by Henry I of England (reigned AD 1100-1135) to his son-in-law, Geoffrey of Anjou, and according to some accounts dates from approximately AD 1127 when Geoffrey was knighted. There is fairly good evidence for this as Jean de Marmoutier, a late-12th-century French chronicler, reported that Henry I knighted Geoffrey and granted him a "badge" of gold lions. A surviving enamel effigy (funerary plaque) supposedly commissioned by his widow (Matilda) to decorate the tomb of Geoffrey shows him with a blue shield depicting gold lions, but this may only have been installed in c1170 when Marmoutier was writing. The idea that William the Conqueror used two lions as his arms (as on the lodge in Grosvenor Park) was once popular but is now no-longer believed.

Surviving seals on charters and other documents provide some evidence for the heraldic symbols actually used by the Earls of Chester. The earliest of these are so-called "equestrian seals" which typically show a mounted knight, often carrying a sword and shield. The shield is usually facing away from the presumed viewer and therefore no arms are displayed, with the owner of the seal being identified in script around the edge. Armorial seals came along later, around the time of Ranulph de Blondeville.

A semi restored seal of Ranulf de Blondeville (1172-1232) dated to 1199-1200 shows what appears to be a lion. It is known that by this time the lion was becoming commonplace as a royal emblem, and Ranulph was a royal relative through Robert earl of Gloucester (a bastard son of Henry I) whose daughter Maud of Gloucester was Ranulph's grandmother being married to Ranulf de Gernon, and so might have wished to emphasise his royal pedigree.

A seal from 1217 (or perhaps a little later) is believed to be the first to depict the more usual three wheatsheaves. It is possible that the sheaves were only adopted when Ranulph became Earl of Lincoln in 1217, or that the changes were associated with the loss of his titles as Duke of Brittany and Earl of Richmond. Another (equestrian) seal of Ranulph as the Earl of Lincoln also shows the three wheatsheaves.

The version in the Fitzwilliam Museum of the "Herald's Roll" is an English Roll of Arms dating to c. 1270-80. This consists of 17 vellum membranes, now bound as a book of 39 leaves, each measuring 9.1" x 10.75". The Fitzwilliam copy (MS297) was painted in color in the 15th century, illustrating 697 shields in 117 rows of 6 per row, with 1 shield over. The original was probably created for Queen Eleanor of Castile. The arms of the Earldom of Chester are depicted as the usual wheat-sheaves as item 48. The three garbs of the earl of Chester appear on the seal of Dervorguilla of Galloway, Lady of Balliol, which is attached to the statutes she gave the eponymous Oxford college in 1282, and which survives intact. On the same seal are three piles meeting toward the base for the Earl of Huntingdon as used by John Canmore, and which also appear on the bridge.

The three sheaves are also found at Baddesley Clinton a moated manor house renovated by Henry Ferrers (1549–1633), a lawyer, diarist and antiquarian. Stained glass represents the marriage of Williams of Ferrers, Earl of Derby to Agnes Lady of Chartley, daughter of Hugh de Kevelioc, Earl of Chester. The arms of the Ferrers of Chartley are impaling the arms of Chester, shown not as the six sheaves of Hugh de Kevelioc but the three as used by Ranulf. However, this is much later stained glass.

Thus, while there is some evidence that Ranulf de Blondeville used the wheatsheaf and lion symbols on his seals there is nothing to really confirm that the previous earls of Chester used them during their lifetimes.



The final shield
Several other potential Earls of Chester exist and are not represented on the bridge. Gherbod the Fleming was frequently named as the first earl during Victorian times and appears as such in the stained-glass at the Town Hall. Matilda of Chester (1171–1233), was briefly Countess of Chester suo jure (in her own right): she inherited from her brother Ranulf in October 1232 and made an inter vivos gift to her son John Canmore in November 1232. With the death of Canmore the end of the independent Earldom became a somewhat messy affair with William de Forz holding the title for four years. The matter not being finally settled until the Earldom was formally annexed to the Crown in 1246 when the rest of the honour of Chester (the land) was bought from the rest of Ranulph's sisters by Henry III.

The last shield on the bridge shows both a royal coat of arms and that of the Earldom of Chester. The role of the Earldom of Chester and that of the Prince of Wales the two roles having been combined in the person of Edward II (in 1301) after the earldom reverted to the Crown. The arms however are not those of the heir apparent as they lack the indicative horizontal white "label of three points" the top of the shield. Beginning with the reign of Edward I, this label of three points Azure (or blue) was used by his son, the future Edward II, to differentiate his arms from those of his father. Without such a label their arms would be identical. Within heraldry this system of differentiating arms is called cadency. The label is placed on the chief (or top) of the shield of arms, with the ends extending across from the dexter to the sinister sides of the shield. It was Edward the Black Prince, heir of Edward III, who first used a label of three points Argent, also white or silver. This has been the label of the heir apparent ever since, without regard to the system of cadency used by other members of the royal family. As the coat of arms combines those of a monarch with those associated with a title held by the heir apparent it would not actually seem possible for anyone to bear them.

This last shield employs the changes in the Royal arms as brought about by King Henry IV, who changed the 1st and 4th quarter from France ancien to the simpler France moderne following his ursurpation of Richard II. The Fleur-de-lis was introduced onto the royal arms by Edward III who considered himself king of France. This version was first granted to the future Henry V as Prince of Wales (1399-1413). The arms were then used by various Princes of Wales from both the Houses of Lancaster (Edward of Westminster 1454-71) and York (the future Edward V 1471-83 and Edward of Middleham 1483-4). The arms remained unchanged during the Tudor dynasty when the title was granted to Arthur Tudor in 1489. With his death in 1502, the arms were re-granted to his brother, the future Henry VIII, 1504-1509. The arms were also later granted to the Prince Edward, the future Edward VI 1537-47. With the arrival of the Stuarts the arms of the prince were changed again.

The combined arms of the monarch/heir and the earl as displayed on the bridge do not appear to be used elsewhere. The related Arms of Chester feature only the three lions of England on one half and the golden garbs of the earl on the other.

In 1923 the Prince of Wales and Earl of Chester was Edward VIII. On the day the bridge was opened Yankee Stadium in New York City also opened. Babe Ruth hit the first home run in the ballpark's history as the New York Yankees downed the Boston Red Sox, 4 to 1.

Book Sources

 * Unseen Chester: Britain In Old Photographs: Derek Stanley (Dr Stanley also provided some postcard images);

Related Pages

 * Suspension Bridge;
 * Bridges (in Chester);
 * Chester Heraldry Tour;

Online

 * Sapper's Bridge at Betws-y-Coed;
 * Attributed arms;
 * Dredge's Suspension Bridge Explained Upon the Principles of the Lever;
 * Heraldry in the Bayeux Tapestry;
 * Lions in heraldry;
 * EARLY ARMS: AS ATTRIBUTED, ADOPTED OR DOCUMENTED;