Author: bexetable

My site is moving!

Hello all,

For those of you who subscribe to my blog, please take note it is moving to http://www.engineeringthought.co.uk where you can continue to keep up to date with my blog posts. This week’s blog, and all future posts will be made on the new site, so please check it out!

Thanks all, Becky.

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Buildings vs. Water

Buildings vs. Water

Last week I wrote about what causes flooding and what we can do to help prevent it. For some communities, both in the UK and abroad living on water, or near water is a fact of life. To avoid being flooded these buildings might be built on stilts or float and adapt as water levels rise. Today’s blog explores these designs.

Floating buildings – Expanded polystyrene is a key component to ensure the house stays afloat. it can either be used to create a slab on the water: flexbase_01_02 or by creating a composite material with concrete:compositehull_001Presumably there are longevity issues with bare polystyrene and that the composite hull will be much longer wearing.

An alternative to polystyrene is to use a reinforced concrete hull: hercules_01 The hull is often left as a void, perhaps filled with polystyrene, with the house constructed above. It is possible though to use the hull as a basement though, as was shown on grand designs: formosa_the_amphibious_house_by_baca_dezeen_1_1000The building is connected to four columns, and can slide up and down these as required by the flood water. This ensures the house stays level as it rises and falls and it obviously means it doesn’t float off during a flood. Much of the design inspiration for these has come across from the Netherlands. In Amsterdam there are entire communities floating on the water, such as the IJburg estate: 14-floating-houses-east-amsterdam-6701All of the houses and walkways are connected to steel mooring poles to ensure they stay in place, floating up and down, as the water dictates.

Building on stilts – It may be very obvious how this design works in the floods, but let’s not knock the simplicity. Here are two UK build houses on stilts:uk-2 article-2031343-0d9eacad00000578-454_468x407Architecturally, building on stilts can be very effective. The top building appears to levitate above the ground due to the slender and dark columns. In contrast the bottom design emphasizes the columns locations with the glazing and wall panels breaking at these points, leaving clear vertical lines through the design. This is accentuated further by the horizontal lines at each floor level, and by the roof line.

All of the buildings featured in this blog have clear architectural / structural overlaps within the design work and must be the culmination of great collaborative working. As more developments creep onto existing floodplains I hope design strategies such as these are utilized and that rather than feeling threatened by more, unpredictable weather and the associated higher flood risks, we actually use it to inspire us. Perhaps we too will create floating communities like those in the Netherlands.

Engineering flooding

Engineering flooding

On Boxing Day massive areas of Yorkshire were flooded. Working on Kirkstall Road, Leeds, and having volunteered with many others to help clean up houses and businesses, I have seen first hand the devastation. Obviously we know that flooding is caused by heavy rainfall, but what is making the situation worse? And what can we do about it?

What might have caused this flood to be so much higher than previous records? 

Climate change is making our weather more unpredictable. Air holds water vapour. If this patch of air then meets a patch of colder air the water vapour condenses, creating rain. With global warming, the air is getting warmer, which means it can hold more water vapour, which means more water falls as rain. Flooding will increasingly occur as climate change affects us globally.

Lastly our own actions can cause flooding in the years to come. A large tree can absorb 100 gallons (450 litres) of water a day, so every time a tree is cut down large quantities of additional water is entering the streams and rivers. When a moor is managed for grouse shooting the ground is drained so that grouse can easily live there. Intensive farming can also mean large run offs into watercourses. Have a look at this article and this article for more information. Lastly, in Greater London, every year the area of Hyde Park, London is concreted over. This means there is no soil and plants to absorb the water, and it runs into the sewer systems instead.

Believe it or not but flood defences can also cause flooding! As a river meanders it has natural eddies, and currents as the water flow interacts with the river banks and river bed. This interaction means the water is slowed down by its surroundings. Flood defences are often built from concrete, so rather than having a soft, bumpy river bank, you get a vertical, flat, solid bank. The water doesn’t get slowed down by the concrete, in fact it speeds up. Flood defences don’t surround every stretch of water, so this style of flood defences simply moves the flooding elsewhere. This could mean onto planned farming flood plains, but can also be into towns and villages further downstream. I live in a village called Woodlesford where Leeds Council kindly built us a small flood defence last year. It protected our village from this winter’s flooding, however the next village downstream, Methley, had the worst flooding on record, with over 50% of the village under water. I expect our new defences had an impact.

So what can we do?

We could continue to build longer, taller, thicker flood defences to keep the water at bay, but knowing how this might cause flooding downstream, surely there’s got to be a better way?

Pickering, North Yorkshire, has a different way of managing the floods. The town was badly hit in the 2007 floods, but rather than build a large, and very expensive, flood defence (costing £3.2million) they looked at catchment measures that would slow down the water movement. Rather than all the water arriving at once, and causing a flood, the water would arrive over a longer time period, keeping the water level low. This article explains the situation in Pickering and this one details the catchment measures used. The measures were completed in 2015 at a cost of £2million. Not only were they cheaper, but planting trees has additional benefits of increased wildlife and CO2 absorbsion too. I should also add that the town didn’t get flooded on Boxing Day!

Obviously these strategies can only be completed in rural towns and villages, but can we mimic this in the city? Turns out we can… Sustainable Drainage Systems (SuDS) provide an urban alternative. SuDS effectively provides large, tanks underground where rainwater can be stored before it enters the city’s drainage system. In normal weather system works as it would in a traditional set-up. In heavy rain though, the water can be stored underground and released in a controlled manner. The city’s water levels are monitored so water is released when capacity allows and stored when it would otherwise cause flooding. Problem solved!

I hope this helps explain what exacerbates and alleviates flooding. Next week I thought I’d continue the theme, but focus on adapting building design in order to protect the property and our possessions when building on flood plains, or river banks.

Amazing Christmas Glasses!

I came across this in the Christmas break and thought the glasses were awesome. I’ve been looking into kaleidoscopic glasses and diffraction glasses to try to understand how it works and here it is…

The science: The lens have tiny holes in the lens causing the light to bend. The holes have been formed as such so that the light bends to create a snowman shape.

However, why do the snowmen not appear to ‘jump’ from one hole to another in the lens? The gaps in the glasses are so small, and so close together, that they are indistinguishable to the human eye. Unfortunately for us our eyes can only process light at a certain speed. This is why when a car is travelling at a certain speed its wheels appear to turn slowly backwards, even though they are clearly rotating forwards.

Simple then? Please tweet or facebook me if you have any comments or questions. Enjoy your day!

 

New Year’s Honours

New Year’s Honours

Happy New Year! I hope everyone is looking forward to what the new year brings them, or at least what it brings once the hangover subsides…

With it being New Years Day it seemed appropriate to blog about the Women in STEM who have been awarded Honours this New Year’s. I wanted to know more about each individual so thought I’d research and add some flesh to their stories, allowing others to also find out more too. Rather than use titles or level of Honour to order them, I have simply ordered them by their surname:

Margherita Joan Biller; For services to Mathematics in Further Education. Margherita is Head of Mathematics at York College, and taught mathematics prodigy Daniel Lightwing, after whom the main character of the film A Brilliant Young Mind was modelled. (Yorkshire!)

Susan Elizabeth Black; For services to Technology. Susan is an Honorary Senior Research Associate in Computer Science at University College London. She is a computer coding activist, author of Saving Bletchley Park and participated in the BBC series ‘Girls can code‘.

Click here to read about the other fifteen women in STEM to receive honours!

Conference: CEMFree

logoAll civil engineers will be aware of CEM1 concrete. It’s a standard concrete mixture using cement to cure and harden. CEMFree has been created by the David Ball Group to entirely replace the cement requirement in concrete.

What’s wrong with using cement?

Portland cement (OPC) is a mined material. It is therefore a finite resource, and has an environmental impact in its creation. During the curing process of cement / concrete large quantities of carbon dioxide is released into the atmosphere (0.95 tonnes / tonne concrete) which has a knock on effect on global warming and climate change.

What is CEMFree?

CEMFree is high performing cementicious binder that can entirely replace the need for cement. It consists of ground granulated blast-furnace slag (GGBS) and pulverised fuel ash (PFA) plus an admixture (kept very secret!?) so uses a large quantity of waste products in its creation.

CEMFree technical comparison to CEM1

  • Better chloride protection
  • 0% permeability
  • Lower embodied energy (<1.5GJ/tonne vs. 5GJ/tonne)
  • 95% less CO2 emissions (0.09tonne/tonne vs. 0.95 tonne/tonne)
  • Reduction in thermal expansion so no expansion gap requirements
  • No requirement for crack control so reduction in steel usage
  • Equal strength at 28 days with a greater strength from then onwards

Publicly available specification is available: PAS 8820:2016

All in all it seems to be a miracle product to help revolutionise the industry into a climate friendly industry. This could presumably also use recycled aggregate to further reduce its environmental impact. It does make you wonder what the admixture is though?

Conference: Passivhaus

ph_logo-strapline_blue_1I had heard of Passivhaus prior to attending the conference, but not many details in what it was and how it affected structural engineering. Put simply Passivhaus is design focussed on minimising energy use during it’s lifetime. (This links quite nicely with Peter Head’s talk focussing on performance focussed, rather than financially focussed tenders written about here.) Passivhaus, as a basis, tends to ensure the following in its design:

  • good levels of insulation with minimal thermal bridges
  • passive solar gains and internal heat sources
  • excellent level of airtightness
  • good indoor air quality, provided by a whole house mechanical ventilation system with highly efficient heat recovery (more info)

There is also a very similar set of standards for retrofitting properties called EnerPHit, since we obviously can’t solve poor building design by simply starting again. The EnerPHit standard is a slightly more relaxed version to Passivhaus due to the difficulties in renovating properties and because there needs to be an element of value for money. I live in a draughty, Victorian terrace, solid wall construction. Making it anywhere close to Passivhaus standards would be incredibly difficult.

Why follow Passivhaus design?

In an average building there is a 60-80% increase on heating costs compared to its design expectations.

78% of homes do not achieve the required air change rate rising high humidity levels, condensation, mould growth and associated health issues.

How does it affect structural engineering?

Thermal bridging: Make sure the structural framework of a building is enveloped within a thermal, insulating layer (and preferably a thick one). In professional work ensure a masonry column supporting a steel beam doesn’t penetrate through the cavity, ensure appropriate construction notes ensure all displace insulation is re-inserted.

Airtightness: During construction a building should have continuous plastic sheeting within the external structure. How do you fix this without using nails or staples? How do you ensure a building’s structure doesn’t penetrate through this?

Communication: Both of the above topics cannot be resolved without considerable communication between architects and engineers. Personally I have a great interest in sustainable design. Unusually I also have a degree in Architecture, as well as currently studying in Civil / Structural engineering. I hope in the future I am able to work on projects that combine both my personal interests, and also combine my skill sets.

Conference Keynote: Angela Brady

s1w-5rq9Sorry for the massive delay in writing my next Sustainability Conference blog post. Life, hockey, youth group running and Christmas preparations have got in the way.

Angela Brady’s talk, of Brady Mallalieu Architects, was two fold. Firstly she spoke of true ecological and sustainable design, but this wasn’t the part that truly inspired me.

The second part of the talk was what really excited me! It was all about the collaboration required with education and it inspired the following teaching activities:

– Use big balloons to visualise how much CO2 on average we currently use in the UK, and compare it to the amount we need to reduce it down to. You could easily use smaller balloons to show what common activities produce too, such as a 10 mile commute.

– Adopt a school is a world-wide initiative that encourages professionals within STEM to adopt a school, and participate in STEM related activities and careers education. This is not a cohesive campaign world-wide campaign, but as with many other simple, yet great ideas it has been picked up in many countries keeping the same principle aim of developing STEM education. Watch out Woodlesford Primary School, I’ll be coming to you in the new year!

– The last idea made me realise exactly where I went wrong in my Architecture degree. Although I gained a 2.1 I was always engineering spaces, rather than creating them. Simply get a pack of straws and some sellotape and instruct the students to create a space. Leave the rest up to them. Some will create rigid structure, some might sellotape a series of straws together to create walls (potentially sloped and curved walls too) A space needn’t have a roof, or even be enclosed, but should simply be created. This activity will help explore the creativity and engineering minds of a youngster and may help differentiate between minds geared more towards architecture and those more scientific or engineering minded.

Let me know if you complete any of these STEM activities. I’ll keep posted about how my adoption of Woodlesford Primary School goes too!

Conference Keynote: Peter Head

peter-head“Peter Head is cited by Time magazine as one of 30 global eco-heroes.” That’s quite an accolade, and not undeserved.

The Sustainable Development Goals are targets that hundreds of countries around the world have agreed to (more info about these and implications in civil engineering in a future blog post). Peter Head was greatly involved in creating Goal 11: Make cities and human settlements inclusive, safe, resilient and sustainable and much of his work focuses on achieving this goal.

Peter believes that all design should take into account the environment in which it is placed. Within building work there are many systems which we interrupt, alter, and change: environmental, social, political, physical, psychological … the list goes on. Without considering the affects of all of these systems we cannot create truly sustainable design. He has set up a charity, The Ecological Sequestration Trust, which is collating every data set available (Europe wide!) that measures these factors. Right down to predicting future health or economic implications of a design. Not only that, but it will be available for FREE.

Read more… (it’s worth it!)

Profiling of women within civil engineering

As part of my HND I had to complete research and write a short report on a topic within the wide realm of civil engineering. I decided to write about the profiling of civil engineering in the media, focussing on the profiling of females.

Summary:

At 6% there are simply too few females within engineering in the UK. Civil engineering is faring a little better at 10% membership, however this still demonstrates a large gender gap within the industry.

This report collates the facts of the current situation, both specifically in civil engineering, and the wider engineering industry. Focussing on specialist and national media outlets the profiling of females in the industry is analysed. There is also a focus on social media since this can both reinforce and challenge gender imbalances. The report concludes by providing recommendations for companies and individuals who wish to address the issue.

To read the report in full please click here.

This is still a work in progress, and won’t be submitted until 14.12.2015, so constructive criticism is welcome. If you want to contact me please use Facebook or Twitter.