Holdfast Training Services Trial Blog

Appreciate there’s been a bit of a deluge of blogging lately but something came up in my office that I thought was interesting. Also apologies for no pretty pictures – I haven’t been able to get hold of anything relevant yet. You may or may not have read in the news recently about a magnitude 7.7 earthquake that hit the Caribbean yesterday. This was quite a large earthquake in a region that has a risk of seismic events due to the North American and Caribbean plate boundary close to Cuba.

Although Sir Robert McAlpine concentrate their construction operations in the UK they also ‘randomly’ have projects in the Cayman Islands for which MDG do some design work. The Cayman Islands are in the Caribbean region south of Cuba close to the epicentre of this recent earthquake. In the office this morning our team had a call to say that a self-supporting tower crane (on pile foundations) on a Cayman site was ‘dancing about a bit’ yesterday. Secondly a sink hole appeared just over a metre away from the foundations of a mobile tower crane (with ballast foundation). At this time we don’t have a lot more additional information other than there were no injuries and the cranes appear to be still standing. The sink hole appeared in an area of limestone and so far no instrument has been able to determine its depth. Whether there are other voids in the limestone is unknown as I don’t think this was picked up in the GI.

It seems that the crane foundations produced by MDG were designed for tropical weather conditions including hurricanes but not for the seismic conditions. The original brief from site did not mention a seismic requirement but I think it would be reasonable for designers to take this into account. I think due to a lack of experience in this area in the UK it wasn’t considered. The problem facing us now as a result is to determine if the cranes can still be used and a possible redesign of the foundations. Furthermore there is a large risk of foundation failure near the sink hole. Whist the crane is still standing, additional loads either from wind or during deconstruction could undermine the weakened foundations. Clearly there is a cost and time impact to the project as a result. Particularly with addressing the sink hole problem which may require significant amounts of concrete to infill.

Does anyone have any experience with seismic and/or sink hole problems? How do you account for large voids in the rock – I imagine desktop study with GPR might be able to pick this up? I can see if we’re deployed anywhere with seismic activity as PQEs this may be something we have to consider and design for. There is guidance in EC8 for seismic design but potentially other more local codes based on experience might be more applicable (in this example US design codes might be more suitable).

TLDR:

1. If you end up doing design work on sites outside of the UK don’t forget to at least consider seismic risks.
2. How do you mitigate against large voids in rock during design and how do you resolve a sink hole issue?
3. Any suggestions on foundation design for cranes against seismic loads?
4. Sorry no pictures yet.
5. Yes there is a whole load of other things that come out of this like who holds the risk etc but this blog is already long enough.

We have just had a seminar with HILTI and they pointed us towards their cloud based design tool for designing baseplate anchor systems, which would have been ideal for Ex STEEL. The free version will allow you to design the anchors and undertake ULS/SLS design to EC2/3. It is quite similar to TEDDs but gives you specifications of products (albeit Hilti ones), making design just that bit easier. It also will show you the calculations, therefore it is very easy to follow and verify what is going on, it also gives useful references.

The limitation with the software is that it assumes the baseplate is rigid and there is no verification that it is, which has to be checked independently in the free version.

https://www.hilti.co.uk/content/hilti/E1/GB/en/engineering/software/anchor-design-software/profis-engineering.html

You just have to sign up for an account.

To give a bit of context at London City Airport we used a chemical anchor solution for the a 7m high 240m long noise barrier, therefore it isn’t just for small scale temporary works.

As you will hopefully realise from reading the title this is not my area…

I was actually listening to a TEDtalk (click to listen!) the other day that put me onto this that discussed more general the uses of bio-fabrication across pretty much every industry from medical to fashion to construction.

The speaker mentioned bio-fabricated bricks and concrete. The benefits come for both the sustainability/climate change perspective and the actual properties of the brick. The cement industry currently contributes 8% of all global CO2 emissions – more than all planes and ships each year. Cement and bricks also require high temperatures to be produced, bio-fabricated bricks and concrete are created at room temperature in a couple of days. These concrete bricks are also nearly 3 times stronger than tradition fired bricks. Finally, these bricks then store more carbon than they produce.

If all 1.2 trillion fired bricks that are currently produced annually were replaced with bio-bricks, we would reduce CO2 emissions by 800 million tons a year.

After hearing this I had a short research into it and found that the US Air Force is using the same company, BioMason, to look at building runways with the same principle, article here. Essentially meaning a high quality runway can be built anywhere in the world in a relatively short time with minimal equipment.

Has anyone seen or heard anything about these bio-fabricated materials? The information I have read is obviously biased, does anyone have any info that argues against?

Also I recommend TEDtalks in general, they aren’t focused on construction or military, but I personally find them all very interesting. Spotify now has TEDtalks Daily and the TEDtalk Interview.

Hey guys,

I found this article on the Wavell Room that I found quite interesting and thought I’d share it with you.

Mobile Nuclear Power Will Enable a Logistics Revolution for the Army

The main idea in the article is that mobile nuclear power is something that would reduce the logistic effort required to power military forces.  Meaning less convoys full of fuel that would be vulnerable to attack; and therefore save lives as well as reduce wasted resource.  The article also explains that future electrical energy demands of military forces are going to continue to grow; I do believe that to be the case, but is there any reductions that can be made by employing more efficient technology (motive being to decrease the vulnerability of the log chain over environmental sustainability in this case)?

Has anyone got any knowledge or experience of the technology the article is proposing who can comment on the technical reality and the benefits & drawbacks?

Also – I would recommend the Wavell Room to anyone interested in keeping up to date with military thinking; I am aware that at least some of the course are already on it!

Following on from Mark’s last blog, I thought I’d give a quick update on where I am and what I’ve experienced so far on Phase 3 in Melbourne. Firstly, Mark has now joined me out in here, working just 5 minutes away from my project office, so It’s good to have some more Sappers around after Auggy and Glynn finished up in June.
I am working for Aurecon, a global consultant operating in 26 countries, primarily across Australasia, Africa, South East Asia and the Middle East. It’s been an interesting move, as Aurecon were the designers (in a Joint Venture (JV) with Jacobs) for the West Gate Tunnel Project (WGTP) – where I was placed for Phase 2 – and have found myself working with some of the team employed on the WGTP, so it’s been interesting to hear their thoughts on the project delivery aspects.
I’ve managed to distance myself from the WGTP (I wanted to get away from it and expose myself to something different) and am working on stage 2 of the Monash Free Way Upgrade (MFU), where I am working in Aurecon’s South Australian and Victoria (SAVI) Bridge Team; the project is another JV so several of the team are from GHD. The MFU project, in very short terms, is a major freeway upgrade to south east Melbourne’s main traffic corridor (think the M2 to London). The route will see several traffic lanes increased to the existing freeway in both directions (some 36kms as part of stage 2 – stage 1 (now completed) saw 30kms widened). This 36kms includes several existing bridge structures that will be widened to accommodate the increased traffic lanes/loads.
My role is officially two parts: ‘Bridge Engineer’ and ‘lead package engineer’, effectively coordinating the design of three of these bridge structures. Each structure is formed of prestressed (post tensioned) precast Super-T girders composite with a RC deck slab. Each structure varies in length, with the shortest being simply supported across two spans of 25.7m and the longest being simply supported across 8 spans varying up to 39m each. All utilise RC piers and abutments except for one prestressed pier. Fortunately, all the bridges (except for the one bridge which will utilise existing substructures previously designed for future bridge widening works) will utilise 400mm square precast concrete driven piles – the exact same ones I got so much joy out of on the WGTP …
So far, I’ve been responsible for producing two preliminary design reports (with the third coming next week) along with ensuring drawing packages are ready for release to the client for comment/approval. This has been challenging as most of my design team are based out of South Africa … communication seems to be the real challenge.
I’ve found myself going back over Richard’s and Shardi’s lectures recently, trying to piece back together lessons on prestress, post tension losses and grillage analysis (looks like I’m that ‘traditionally 1 in 3 students will…’ student) whilst learning the software ‘Midas Civil’ to model my bridge decks and structures (the software of choice in my team).
Like Ash’s earlier post, it seems all the younger engineers rely on the software first to model their structures without doing ‘hand calcs’ – while the more experienced engineers are using the software after running numbers on paper first.
I’m now modelling some of my Super-T girders in Midas, as well as performing some grillage analysis (slowly I must add). Midas is interesting as you can model the entire structure, including the substructure and piles, and run static/moving load analyses on the entire structure – to me, this seems like there’s a lot that could go wrong while being very confident/relying on the input parameters/data to be correct John’s ‘Rubbish in = rubbish out’ keeps coming to mind).
Anyway, here’s some pretty pictures of what I’m modelling at the moment – hopefully it works …

Modelled Super-T’s I set up in MIDAS Civil

I am working for a multidisciplinary consultant called SMEC. Most of you won’t have heard of them because they don’t operate in Europe but SMEC’s Signgaporian parent company also owns Robert Bird Group so may move into Europe before too long.

SMEC was formed from the team that delivered the Snowy Mountains Hydroelectric Scheme 70 years ago for the Australian government. The scale of the project was insane (more details can be found here http://www.smec.com/70years/).

I am working as a structural engineer within the transport division which mainly focus on bridge design, retaining walls and gantries. Since December I’ve been involved in Proof Engineering for the Westgate Tunnel Project (WGTP) – effectively independent checking JV produced designs for code and project compliance. (Basically resolving all Dan’s phase 2 RFIs). So far I’ve looked at the structural impact of out of tolerance construction, pile and pile cap redesign, amendments to RC detailing and temporary works packages.

Away from the WGTP I’ve also assisted with load assessments of new cranes on existing structures. As the client required an answer in a short time-frame, we used existing models to conduct a comparative analysis between the maximum loading from existing load cases and the new vehicles loads to determine if the new vehicles could be trafficked. Initially the loads exceeded the capacity but manipulation of dynamic and combination lane use factors by more experienced engineers reduced the loading to under 80% of the maximum competitive load. Has anyone else come across any ‘tricks-of-the-trade’ that would be useful to military engineers?

Anyway Enough about what I’m up to. From recent blog posts the list below is where I think we’re spending Phase 3. Please feel free to fill in the blanks, I’d be interested to hear about what you’re working ok and how your finding Phase 2 compared to Phase 3.

• Dave – Arup Oz
• Gareth & Ali – USACE
• Rob – electrical design linked to EDF and Scottish windfarms?
• Jambo – Plymouth bases building services design
• Alex – ?
• Ben – BP?
• Gary – WSP?
• Jon – Arup uk?
• Al – SRM Temp Works
• Dan – Aurecon
• Ash – Bam Nuttal
• Tom – Wentworth House temp works design
• Colin – ?

In the vein of sustainability that seems to (thankfully) be gaining traction, I was reading the Arup newsletter and came across the ‘Construction Declares’ petition (https://www.constructiondeclares.com/).

The intent is ‘to unite all strands of construction and the built environment in a public declaration of the issues facing our planet and a commitment to take positive action to prevent climate breakdown and biodiversity collapse.’

Since June 2019 over 800 UK practices have made the declaration, with firms in 17 other countries (including Australia) beginning to sign up. With the construction industry contributing to 40% of global carbon emissions, this seems like a positive step. However, it has yet to set any SMART targets, remaining at present the start of a ‘wide-ranging declaration of intent’. Let’s hope it goes somewhere.

Arup have signed up and released a detailed internal sustainability plan. They have also incorporated performance indicators for the 17 UN ‘Sustainable Development Goals’ (SDGs) into their design process and have project management tools to match.

I’d be interested to hear how other consultancies are treating the problem? Has your Phase 3 organisation signed up? Can you be your firm’s ‘Greta Thunberg’ and start the change from the inside (…and tick that UK-SPEC box)?

A few weeks into my phase 3 attachment and I am working on the design of the M&E install for the onshore facilities of an EDF wind farm in Scotland. EDF are the client with Skanska as the principal contractor. My design consultancy have been employed by Skanska to design the M&E. Unfortunately, General Electric and National Grid are also involved and have employed an independent consultant to review the electrical design. One recommendation that he has made is that all final circuits need to be terminated into a junction box in each room. The junction box is then to be connected to the distribution board via multi-core armoured cable. He believes that this will save time on the install and is more cost effective. I am recommending a standard install to and from the distribution boards and am struggling to see the benefits of employing his method.

Any thoughts from the M&E crew on this?

Happy New Year to you all!

I wanted to share with you a useful tool I used in my last TMR and may be helpful with analysing secondary or tertiary data for Theses.

During Phase 1, the E&M course used Webplotdigitizer to take points from a graph in a pdf.  This allows you to plot your own graph in Excel making it easier to analyse and manipulate data.  For example, plot your own results against the secondary data in a comparison.

There are multiple tutorials on You tube, so I won’t bore you with a wordy explanation and screenshots of how to use it.

Enjoy!