The main point:
The article on the experimental reconstruction of a short section of the A9 just south of Inverness (NCE last week) took me back to pre- and post-war days to roads over which I travelled in the 1930s and 1940s by car and bicycle.
In 1936 Team Valley Trading Estate at Gateshead on Tyne was under construction. A road network was involved of single and dual carriageway of various widths, the construction being of reinforced concrete with a 20mm black top wearing course being added after the war, all to the design consultant’s standard.
By the 1970s the roads generally were showing unacceptable signs of wear and it was decided that complete reconstruction should be undertaken to a standard acceptable for adoption by the local authority.
The breaking out of the old concrete slab went well and it was observed that its quality was suitable for breaking into a good granular base course. A trial section was broken up using an Arrow Breaker which was a tractor mounted machine manufactured by a local firm and carrying a heavy drop hammer with vertical and horizontal movements of about 2m and 1.5m respectively.
This was the forerunner of current practice of making use of recovered materials. A very considerable saving was achieved as the broken concrete did not have to be removed and replaced with standard granular sub base.
After some 30 years the road is still in perfect condition except for the usual disturbances caused by public utilities.
- JW Hall (M), email@example.com
As a retired highway engineer, I found the Greener Courses article (NCE last week) most interesting.
At least seven years ago, I was expressing concern about the use of 14mm stone in stone mastic asphalts (SMA) and its very poor performance and short life when used on nonmotorway locations. Why has it taken so long for a mainstream body of opinion to question the specification?
I have been saddened to see engineers still specifying 14mm SMA, when I know its short life will result in much waste of money/resources. Have we lost our ability to question specifications when they are so obviously wrong?
- John Hague, firstname.lastname@example.org
Is it electrifying?
All but one of the electric cars I have seen described have a range of less than 100 miles (161km) and would be recharged by plugging into a power source.
Because of their range they are really only suitable for urban use, adding to traffic congestion and limiting the need and use of public transport.
Moreover the road sides would be cluttered with cars having their batteries recharged.
Government should not be subsidising the purchase of this type of car but investing in public transport.
An alternative could be a car with a removable battery, which would be extracted from the vehicle and reinstalled mechanically. These batteries would be owned by the service stations and hired out.
The batteries would have a charge allowing a range of up to 483km. Changing to a fully charged battery would be similar to refuelling at present.
For this system to work there is a need to standardise on the battery which would be used on all cars and stocked by all service stations. Government and/or EU legislation might be needed.
Other advantages with this system would be that service stations could continue to function through the transition of fossil fuels to electric power with minimum disruption.
- Harry Rook (M), email@example.com
In a spin
I refer to David Johnson’s letter regarding signs warning high vehicles of a roll over potential at a roundabout. The signs as shown in the photograph are in fact entirely consistent.
Roundabouts are designed on the principle of slow-on fast-off and to this end the minimum radius of entry path curvature is kept below 100m to ensure that vehicles cannot enter the roundabout at more than 30mph. The tipping hazard is therefore most likely as the lorry turns left on entry to the roundabout as shown on the sign.
The letter carries the caption “A sign of the times”. I would suggest that the sign of the times is that so many drivers think that they know more about traffic design than the traffic engineers who do their best to design our roads to keep them safe. It is very sad that this includes some civil engineers.
- Roger Curtis, firstname.lastname@example.org
Not falling over
Further to the comment by David Johnson (NCE 25 June) regarding the inappropriate use of a roundabout warning signs with supplementary plates.
In the UK, a vehicle entering a roundabout (particularly at excessive speed) would exhibit a lateral force (with consequential load shedding) to the right-hand side.
I suppose a whole new argument could be started regarding how much we should provide signs that state the obvious − in this case, is the roundabout warning sign enough?
Is it not reasonable for drivers to work out for themselves that they have to slow down or they’ll fall over. Ah …I see the problem!
- Ian Henry, travel planning team leader, Strategic Traffic Studies, Durham County Council, email@example.com
Recently, a number of letters, for example the contribution from Martin Cure, (NCE last week) have bemoaned the lack of applications from undergraduates.
With final years ending, and with the recession increasing competition for positions, I expected that the more proactive civil engineering students would be sending out speculative CVs.
I have received just one such CV this year. Is my experience unique? It raises the questions:
- Are undergraduates so pessimistic about job prospects that they think speculative CVs are pointless?
- Do they simply not want to work in my own field of geotechnical engineering or are they going into other industries?
I hope it’s not the first. I want to tell undergraduates that a targeted, speculative CV carries more weight than one “scatter-gunned” out by an agent as it shows motivation and proactivity.
Don’t university careers advisors make this clear? The situation may be complicated by company recruitment freezes, but undergraduates need to realise employers will go to a forward thinking, proactive applicant first when the recession starts to ease. And yes, I have been into a local university to promote my own company.
If it’s the second, I can only urge undergraduates to stick with civil engineering and especially geotechnical engineering.
An interesting and varied career, taking you round the world, can be yours if you want it.
Civil engineering undergraduates, please be assured our industry desperately needs numerate graduates. Send us your CVs please. You must be out there.
- Ian Froggatt (M), Capita Symonds, Salford, firstname.lastname@example.org
Engineers at the check out
Further to the recent letters with regards to graduates, as a recruitment consultant with eight years experience in the structural engineering sector and a graduate myself I would like to add my personal comments.
I think it is ridiculous for anyone to expect free workers when the minimum wage is £5.73. Free working was fine when trainees were school leavers living at home supported by their parents, but graduates are adults who usually have living expenses and debts to pay.
I think some of the previous generation need to realise that things are different nowadays otherwise all the graduate engineers will be working in supermarkets and petrol garages instead of design offices and construction sites to make ends meet.
This will result in a massive skills shortage when the market improves and wages will go sky high to unsustainable levels.
Up until recently, it was very difficult to recruit a good graduate with experience. I appreciate the current economic climate does make things difficult, but the industry must remember that the graduates of today are our engineers of tomorrow, and without pay there may well not be any.
- Sam Davis, email@example.com
To guide or not to guide…
With reference to Tim Shillam’s letter “Mixing it Up” (NCE last week), some of the advantages of a guided busway over the suggested unguided busway are:
- A narrower corridor - the central strip between guideways running in opposite directions need only be 800mm (to avoid wing mirrors touching) and each guideway is only 2.6m wide between upstands
- Very high ride quality
- Safer high speed operation (100kph)
- No need for expensive signalling
- Less impermeable surface − reduced surface water management
For various reasons the 25km Cambridgeshire scheme includes short lengths of unguided busway - so the project team has direct comparison.
Regarding the earlier letter from Lewis Lesley that his company offered to provide a light rail alternative between St Ives and Cambridge city centre (over 20km), including electrification and rolling stock, for £65M, it is no wonder they did not receive a reply from Cambridgeshire County Council.
Such a project, including park & rides, stations, junctions and bridges would likely cost six times that figure.
- Robin Sharp (M), Cambridgeshire guided busway design manager, firstname.lastname@example.org
Waiting for a rainy day?
Back in March you reported that Thames Water had shelved proposals for Abingdon Reservoir which was intended to safeguard supplies into London. It would also have provided some relief against winter floods and summer low flows in the rivers Thames and Kennet.
Now this week you report that the UK Climate Projection Study suggests higher winter and lower summer rainfall.
Surely, rather than delaying Abingdon it ought to be completed with great urgency, rather than, as in so many things, suffering delay.
I feel the re-birth of the Water Resources Board has never been more needed.
- Rodney Bray (M), Thatcham, Berkshire, email@example.com
Your views & opinion
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