Bridge pedestal grit blasted

The bridge reopened on the 17th July to some small fanfare. This was after the council’s appointed engineers had blast cleaned the cast iron pedestals so that they could be fully examined for cracks, and the case for continued safe operation could be made. 

There are cracks evident in all pedestals to a lesser or greater degree, but they are now assessed as not being critical to structural integrity, provided that the pedestals are not overstressed, which means minimising the movement of the chains that run over them.

Chain heating arrangement (pedestal within housing)

Bridge Chain heater

The temporary solution, which allows the current limited use by pedestrians and bikes, is to heat or cool the chains that run over the pedestals to maintain temperature, so as to keep them in approximately the same place avoiding excess pedestal stress.  This is obviously a 24×7 energy-intensive business, a least-worst solution for the time-being.  It’s worth noting that even with only pedestrians and bikes crossing, the bridge still sways a little, it is very much a live structure.  The current and much reduced-cost proposal for shoring up the bearings on top of the pedestals (“stabilisation works”) is to replace them with elastomeric sliding bearings, at a total cost of around £6m as widely reported, a figure that doesn’t seem unreasonable.  Others can judge whether this is a good enough solution for the long term.  We’d prefer to be without the nagging doubts of the hidden cast iron bolted-in parts in critical structural positions, to allow the engineering of a robust 100-year + solution using easily replaceable bearings. This wouldn’t be expensive in the scale of the total repair bill, and as we described early this year, fixing the recurring problem effectively for good.

Without going into further exhaustive detail, which can be found in the references listed below, the main issue remains who will pay for the repairs. The most sensible option is to substantially dismantle the existing bridge with the COWI-Foster structure, or other temporary bridge in place for the duration. This would allow it to be properly repaired to a higher quality than can be achieved onsite, including replacing the troublesome cast iron, and might be quicker overall.  Consideration should also be given to lightening the structure via a lighter/improved roadway as we’ve mentioned before, so as to lower bridge loadings, potentially raise capacity a little, and we’d very much like to see wider pathways for pedestrians & bikes.

The latest update from the Task Force shows that our council leader and the newly re-appointed government minister responsible, Baroness Vere, are again at loggerheads, this time over the relatively small sum of £6m for stabilisation works, which is why they haven’t started.  If they can’t agree on this, how ever will they agree on the £100m+ full repair bill ?  We call for a ceasefire and end to hostilities by letter.

References

• Bridge Task Force documents
• New Civil Engineer – bridge reopening 
• H&F Bridge page including letters to and fro.
• Barnes Village Bugle (August) with significant detail and discussion of the proposed ferry, now mothballed.

Hammersmith Bridge with Toll, 1827, designed by William Tierney Clark (Hammersmith & Fulham Archives)

We’re pleased to see that a ferry operator has finally been appointed, and conversely disappointed at a low proposed (peak) capacity of 800/hr. total, i.e. 400 each way, cost – not free – £1.55 proposed, though included in hopper & concessionary fares, restricted operating hours of 6am-10pm, and of course the service delay until later this year. 

But as the tale below shows, a temporary bridge was the right solution 140 years ago when the original bridge was falling down through neglect, and remains so today, on the second anniversary of bridge closure.
Accordingly, we  wrote to the Prime Minister recently.

John Dixon by Ian Pearce

Last month we were sent a copy of the lavishly illustrated hardback ‘John Dixon’ by Ian Pearce, published in 2019 (cover shown), which has a fascinating chapter illuminating the design & construction issues of the original Tierney Clark suspension bridge, and its rebuilding as the current bridge, which John Dixon’s company took over in the 1880’s, under Bazalgette and his son Edward.
Readers may order the book direct from the author at the much reduced price of £18 (including UK p&p) using this link.

Hailstone’s book

Here we also need to mention the joint endeavour by the Fulham and Hammersmith, and Barnes and Mortlake Historical Societies in recently updating Charles Hailstone’s 1987 book: A History of Hammersmith Bridge.

To say that the various accounts show history repeating itself would be rather an understatement. Included in Pearce’s book are warnings writ large for those again contemplating tolls and ferries.

A comparative list between then & now:

Hammersmith Bridge under reconstruction, showing Temporary Bridge, by John Archibald Webb
(Richmond upon Thames Borough Art Collection)

✔ A toll that irritated residents both sides of the bridge.
✔ Ownership issues preventing adequate finance & oversight.
✔ Lack of maintenance leading to near collapse.
✔ Concerns over bridge loading capacity, weight.
✔ Questionable strength of bridge chains and hangers.
✔ Roadway disintegration.
✔ Use of inappropriate materials for cost reasons.
✔ Engineers reports unheeded, or “disappeared”.
✔ Plan for a temporary ferry with low capacity & limited hours.
❌ Effect on navigation and the Boat Race.
❓ Temporary bridge, 23ft wide with a separate walkway.

It’s of note that Tierney Clark’s Széchenyi Chain Bridge in Budapest, of similar design to his one in Hammersmith and earlier in Marlow, is also currently closed – for repair and rebuilding – not for the first time,  perhaps with some familiar issues ?

During Bazalgette’s 1880’s bridge reconstruction, a temporary bridge was built both wide enough for traffic, and with spans sufficient for navigation and to allow the Boat Race to continue as shown here, in response to the inadequacies of a proposed ferry, an outcry from the residents of Castelnau (@TfL take note), and at the time, a statutory duty to maintain a crossing, needing an Act of Parliament to circumvent.  Eventually though, the rebuilding was done in just 30 months, and at a cost of £82,177 which is about £10.5M in today’s money. 

It’s now just over six months since the Bridge was closed to pedestrians and cyclists, and over 22 months since it was closed to traffic, yet there is neither a Bridge repair contract nor an alternative crossing facility in place. Repair work will not progress until there is forward funding to pay the estimated £128M cost (over and above TfL funded temporary stabilisation works). Government funding has been offered conditional on a LBHF contribution of £64M, 50% of the cost, as reported in last weekend’s Observer. This is evidently way beyond the LBHF resources; whilst there has been media reference to the potential of council reserves, the 2019 external auditors report states “…Council do have ongoing financial pressures, which need to be addressed in the medium term… As a result, the Council is now maintaining a reserves position that is below the average when compared to other London Boroughs”.  Government funding for local authorities has been considerably reduced in recent years, and an uplift in council tax, aside from social and political issues, would only generate additional income of around £650K per 1% rise.

Foster & Partners bridge proposal

Hammersmith Bridge would seem to be a unique and most deserving case for special funding, and it is so frustrating that the critical issue of project financing is not addressed in the government Task Force meetings, despite its obvious importance. However we understand that, separate to the Task Force meetings, LBHF have been exploring initiatives which draw on the private sector, not only in the Foster/Ritblat temporary bridge proposal, but also investigating the viability of private funding, secured on an income stream provided by a toll: this financing method which has been used for a number of other UK bridges, including in London, the Dartford Crossing. LBHF residents would be likely to cross toll-free. We understand LBHF have now submitted a comprehensive financial plan to Grant Shapps based on this funding approach.  Consideration might be given to 1% of the toll to be set aside for social funding in Hammersmith, similar to the arrangement on the London Eye ticket price.

Some valuable comparative information has emerged regarding the financing of other London bridges. For the recent £9.6M repairs to Albert Bridge, RBKC paid £2.6M in line with many other bridge repairs as recent research indicates, while TfL paid £7M. The £9M refurbishment of Chiswick Bridge was paid for by TfL. Since TfL are out of funds, the recent upgrade of Wandsworth Bridge was paid for by Wandsworth Council – but since the bridge is a simple cantilever structure, fabricated in steel in 1940, the overall cost was only around £6M, less than 6% of the bill for the 1887 Hammersmith Bridge.

These comparative repair costs highlight the unique problems with the bridge, an ornate, Grade II* listed structure constructed from cast iron and wood in 1887, two years after the first internal combustion engine came off the Benz production line. Before the traffic closure in April 2019, over 20,000 vehicles and 2,000 single-decker buses were crossing the Bridge daily; until total closure in August 2020 16,000 pedestrians and cyclists were crossing daily. Until 1998 heavy goods vehicles and double-decker buses were using the Bridge.

The Bridge is clearly not fit for this purpose. If the outward appearance of the Bridge is to be retained, then within the decorative outer claddings the structure has to be not repaired, but replaced, to create a Bridge which is able to sustain the demands of 21st century traffic.  We discuss this in more detail in the accompanying article.

We’ve made several meaningful and thought-through suggestions in the half-dozen articles, and as many letters to the main bridge protagonists in the last year, from simple widening the pathways to make the bridge more accessible, and to improve public safety, to ways to invisibly fix the 19th century structure for the longer term, in a maintainable 21st century way.  Put simply, we believe the current premise for repairs has set the engineers off on a bit of a wild goose chase.  While much good work has been done, how much is useful under an alternate premise, and at what opportunity cost ?

Bridge anchor (cover removed)

As we pass six months since complete closure, we’ve made it crystal clear that there appears very little, if any, value in repairing the much-debated, though normally invisible, cast iron pedestals shown.  We continue to be dismayed that so much attention is paid to evaluating and repairing these simple yet demonstrably unsuitable bolted-in components (c.f. Mott MacDonald summary and more detailed  Aecom report) when replacement with modern equivalents is an obvious solution.  Not only that, but by including, as we’ve suggested, a built-in lifting or jacking mechanism for the chains in a new design pedestal, future maintenance inspections and bearing replacements (the cause of many of the current problems, and certainly the precipitous closure), would be reduced to perhaps scheduled weekend roadway closures every 5 years or so, at low cost and public impact.  This, without even considering the environmental and financial running costs of the proposed chain heating and monitoring systems that would no longer be needed. 

Surely we can’t be the first to spot such an opportunity for a better and long-lasting engineered solution at lower overall cost – plus the opportunity to cut a whole phase of repair work ? The question is why can we only find passing reference to renewal as an option in the copious Aecom report?  Which is where we return to the issue of the premise, assumed to include retaining the original components.

A false premise

Temporary pedestal support frame

The TfL drawings shown at the public meeting in October, to which we responded, show a temporary support frame for “emergency stabilisation” – already designed – that could be better used during pedestal renewal, using offsite built and tested replacements, instead of a long and expensive (£13.9M + percentage  – say half – we don’t have a detailed cost breakdown) of the permanent stabilisation costs, totalling c.£30M. 

The current proposal for onsite shoring-up would hardly respect the Grade II* listing, Bazalgette’s design, or materials (assuming that’s the rationale), rendering the pedestals unrecognisable as historic components, especially when infilled with [c. 6 tonnes] of steel fibre reinforced concrete as proposed, and would, according to the Aecom report, leave further nascent cast-iron problems, including a possible failure mode where the cast iron collapses onto the unusual prop/concrete/cast iron mix. The cast iron pedestals would instead make fine museum pieces, to accompany Tower Bridge’s stream engine, removed from service when proven equally obsolete over 40 years ago.

Foster & Partners / Delancey temporary bridge proposal

Bridge proposal

We were surprised and excited in equal measure to see a radical new proposal published by the council, in partnership with Foster and Partners and Sir John Ritblat of Delancey, the company now owning the Earls Court development site.  This is designed to temporarily solve the conundrum of getting across the river while the original bridge is repaired.  Details can be read on the council’s website, there’s obviously more detailed work needed to bring it to fruition.

Key points are:

• Raised temporary deck envisages crossing for vehicles, pedestrians and cyclists on 2 levels.
• The deck would overlay and rest on the footings of the existing bridge.
• River traffic could pass underneath.
• Costs believed lower and timescale significantly faster than previous plans.
• Partial dismantling and offsite refurbishment of the existing structure while temporary structure in place.
• Transport Secretary given outline brief by H&F Council Leader on 25th November.

There’s been generally positive comment in the press and social media, and we were particularly pleased to see our favoured approach of offsite construction/restoration being embraced, which should improve the quality of the end result.

Funding

Since the public Task Force meeting in October, there have been snippets of gossip from behind the scenes, but little significant  progress to report. TfL have been instructed to pay for a temporary ferry river crossing, and to contribute £4M towards the bridge stabilising work, drawing from their recent £1.8B government emergency funding.

Central government has now promised to fund the project, conditional on a substantial contribution from the local authority.  LBHF report that funds are not available to meet this demand.  The Hammersmith Society and others are pressing the government to take the long view, and release the Bridge funds now, and negotiate separately with the local authority,  and this is set out in our letters to the Task Force chairman and the Secretary of State for Transport, as previously published.

Enquiries to LBHF and other parties have revealed some further context to the funding problem.  We understand that Hammersmith became involuntary owners of the Bridge in 1985, when the government abolished the GLC (Greater London Council); there is no record of a condition audit taking place at the time, and no maintenance arrangement accompanying the gift, which was perhaps a mistake.

In normal circumstances structural repairs to the bridges over the Thames have been paid for by TfL, with costs of a fraction of the c. £150M budget for Hammersmith Bridge;  this very substantial cost arises largely from the design of the structure with cast iron, and design restrictions on the repair methods imposed by Historic England Grade ll* listing status. 

Following the Zoom public meeting three weeks ago, we considered our recent articles on the bridge, and, as promised, wrote to Grant Shapps MP, Secretary of State for Transport,  Baroness Vere, Chair, and Dana Skelley, Director of the Bridge Task Force, as shown below (click to open).

 Letter to Grant Shapps MP, Secretary of State for Transport

Letter to Baroness Vere, Chair of Bridge Task Force

Letter to Dana Skelley, Director of Bridge Task Force

We’ve made suggestions borne of our various architectural & engineering experiences, and feedback from members who contributed, balancing aesthetics, cost-effectiveness, speed of the works vs. longevity & value to the public. 

We think the repairs might be done more quickly and cheaply, and the result might last longer and be more useful as a bridge, if the slightly modified approach were taken, as outlined.  As an alternative, we’ve also dared to think the unthinkable given the proposed closure duration and costs, and suggested bridge replacement. An architectural competition could be held to decide how to best reuse what is there, but make it fit for the next century as Bazalegette did to the 1827 original, back in the 1880’s.  As we’ve said, this need not involve a total loss of the iconic appearance; it would be up to innovative designers to come up with the solution – we’ve already seen ideas coming from local architects and engineers.

With huge sums of central Government capital and revenue expenditure being regularly announced, the cost of solving the Hammersmith Bridge problem seems small by comparison, and given the considerable inconvenience already endured both sides of the river by some of the most vulnerable members of society, the project deserves immediate and full financial support.

Many Society members joined the Zoom public meeting with the Bridge Task Force a week ago. A FAQ, links to Task Force reports, and a copy of critical correspondence between the Task Force chairman and LBHF immediately prior to the meeting, can be found on the council website, and a recording of the meeting can be played by clicking on the video image here.

Our report on the meeting has to tread carefully to resist the winds of political bias which seem to be jeopardising project navigation. The exchange of letters between the chairman of the Task force and LBHF reveals the entrenched and opposing positions of government and local authority concerning the funding of the bridge repair programme. At the meeting the Task Force chairman declared that the government is ‘completely ready to fund the entire project subject to local contribution’ – the proportion of this contribution was not defined – while the LBHF deputy leader reported that substantial local authority contribution has already been paid out for the bridge work to date, and LBHF could not afford any further funding. 

Alongside the funding impasse, the meeting provided an excellent explanation of the bridge problems, the anticipated repair works, the investigations in progress, and proposals for temporary pedestrian crossings.

A summary of the current critical issues:

• Project funding: government funding is confirmed conditional on LBHF contribution; LBHF and TfL have no funds available to contribute. TfL to fund the ferry crossing and contribute £4M towards the stabilisation works as a condition of their £1.7B second government support grant.
• Engineering works: completion of pre-design survey work requires a further 4-month programme to inspect each upstream pedestal (the lower housings at each end of the suspension chain); the contractor is ready to proceed with the work on release of funding. See project funding statement above.
• Project Plan: LBHF report that they have provided the ‘robust project plan’ called for by the chairman. We would expect to see a review of alternative options including the replacement of the bridge with a modern structure, taking into account the cost and programme viability of restoring a bridge built over 130 years ago for a very different traffic type and density. 
• Temporary crossing (stage 1): ferry transport for pedestrians and cyclists has been investigated and can be operational within 66 days of contract commitment and release of funding.  See project funding statement above.
• Temporary crossing (stage 2): pedestrian and cycle use of the bridge can be resumed for a  limited period after installation of temporary stabilising frames over the pedestals.  Obtaining the necessary statutory planning consents and carrying out site construction would require around 7 months; estimated cost is £14M.  See project funding statement above.
• Project programme: overall period for completion of the works as currently foreseen, including measures to meet TfL increased traffic loading requirements, is estimated at approximately 6 years – from release of funding.

Bridge permanent stabilisation – cast iron pedestals – slide from meeting

We’re a little concerned that substantial time and costs are currently being allocated for shoring up the cast iron pedestals that are clearly a long way past their best:  4 months/£2.3M blast cleaning prior to 7 months investigation and temporary stabilisation/£13.9M, followed by 21 months/£32M permanent stabilisation, in addition to a planned temperature control system to lower the risk of further cracking.

Hammersmith Bridge closed: Motor traffic:10th April 2019; Completely:13th August 2020

A head of steam is certainly building up for Bridge repairs, especially as winter approaches, but it remains to be seen whether this will translate into action.

After much media/social media coverage, including stories on London TV news, a task force was set up on 9 September, chaired by Baroness Vere (roads minister), which includes representatives of the local councils, TfL and Network Rail (for their experience of cast iron bridges), the Port of London Authority and GLA. The task force’s project director is Dana Skelley, a chartered civil engineer, formerly director of roads for London and responsible for the London-wide roads modernisation ahead of the London Olympics and the repairs to Hammersmith Flyover.

Completing the full repair of the Bridge is currently predicted to cost £141-£163m, with stabilisation just to allow safe pedestrian and river traffic at £46m, considerably more than first envisaged.  We covered the announcement of a temporary pedestrian/cycle bridge in April, which is believed to have been costed at less than £10m.  Before lockdown, planning was to be sought for this during the summer with construction starting this autumn, but this has not happened.  We followed up in June with our ideas about widening the pathways while work progresses elsewhere, making the bridge suitable for safe bidirectional cycling and walking; these are also clearly ideas yet to be considered given the new circumstances of complete closure.

Neither the Council nor TfL can finance costs at this level, so government support is essential. The possibility of tolls to finance the work has not been ruled out, indeed some are campaigning for this to make more funds available to speed up the work.