Blog

What is shotcrete?

Most people are familiar with concrete but not with shotcrete. Shotcrete is a method of spraying a wet mix of concrete onto a frame of steel reinforcement. This reinforcement can be steel rods, steel fibres, or a steel mesh depending on the design detail. A high-pressure hose is guided over the structure to form an even layer and then shaped to the desired form.

Shotcrete

Shotcrete, was originally called “Gunite” when Carl Akeley designed a doubled chambered cement gun in 1910. His apparatus pneumatically applied a sand-cement mixture at a high velocity to the intended surface. Other trademarks were soon developed known as Guncrete, Pneucrete, Blastcrete, Blocrete, Jetcrete etc. all referring to pneumatically applied concrete. Today Gunite equates to dry-mix process shotcrete while the term “shotcrete” usually describes the wet-mix shotcrete process. At point of application, both are typically referred to as shotcrete.

In 1920, this innovative process first spread to Europe, India and South Africa before finding its way to the American west coast and South America, despite the geographical proximity. This may be the explanation for the term “gunite” (Spanish: “gunita”), stemming from this earlier period, still being used a lot in Spain, whereas South American countries prefer the term “sprayed concrete” (Spanish: “hormigón/concreto proyectado/lanzado”), as well as “shotcrete” stemming from a later period of development.

Shotcrete can be applied by two distinct application techniques, the dry-mix process and the wet-mix process.

  1. Dry-mix shotcrete – The cementitious material and aggregate are thoroughly mixed and either bagged in a dry condition or mixed and delivered directly to the gun. The mixture is normally fed to a pneumatically operated gun which delivers a continuous flow of material through the delivery hose to the nozzle. The interior of the nozzle is fitted with a water ring which uniformly injects water into the mixture as it is being discharged from the nozzle and propelled against the receiving surface.
  2. Wet-mix shotcrete – The cementitious material, aggregate, water, and admixtures are thoroughly mixed as would be done for conventional concrete. The mixed material is fed to the delivery equipment, such as a concrete pump, which propels the mixture through the delivery hose by positive displacement or by compressed air. Additional air is added at the nozzle to increase the nozzle discharge velocity.
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ACSES Engineers are proud sponsors of Young Diggers

We at ACSES Engineers believe the promotion of mental health awareness is incredibly important and a worthy cause to be involved with.

Especially for those brave men and women that represent our great nation and have the courage and dedication to serve in our Armed Forces.

Too many of our diggers (and their families) have difficulties coping with the stresses and fall-out of military service.

Young Diggers is an organisation that provides support and programs for serving and ex-serving military personnel (and their families), and ACSES Engineers are proud and honoured to be a sponsor.

Please visit www.youngdiggers.com.au for more information. Or like their Facebook page.

Young Diggers 1

Young Diggers 2

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Project: 278 Bunnerong Road Hillsdale

Work has begun on the project located at 278 Bunnerong Road Hillsdale. Meso Solutions are currently inserting sheet piles and bulk excavation works are set to take place shortly.

Great design by Nick Krikis and the architects at KTA. Bradley and the team at Jebeko have got things well and truly under control. ACSES Engineers are proud to be involved in this terrific development and honoured to be the Project Structural Engineer.

Project Specifications:

*   Three below ground basements
*   Two buildings on a common transfer slab
*   84 Residential Units in total

Our Scope of Works

*   Design and Detail the following:
*   Shoring & bulk excavation solution
*   Foundations solution
*   All concrete slabs
*   All concrete columns & walls
*   Specialist Engineering Assessment Report including full calculations package for Sydney Water
*   Shoring Report including full calculations package for Roads and Maritime Services
*   Dilapidation reports covering public assets and neighbouring properties


278 Bunnerong Road Hillsdale

 

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The history of concrete

Have you ever wondered how the humble but ever enduring concrete came about? In this post, we find out its history.

Early Use of Concrete

The first concrete-like structures were built by the Nabataea traders or Bedouins who occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan in around 6500 BC. They later discovered the advantages of hydraulic lime — that is, cement that hardens underwater — and by 700 BC, they were building kilns to supply mortar for the construction of rubble-wall houses, concrete floors, and underground waterproof cisterns. The cisterns were kept secret and were one of the reasons the Nabataea were able to thrive in the desert. By about 5600 BC along the Danube River in the area of the former country of Yugoslavia, homes were built using a type of concrete for floors.

Egypt

Around 3000 BC, the ancient Egyptians used mud mixed with straw to form bricks. Mud with straw is more similar to adobe than concrete. However, they also used gypsum and lime mortars in building the pyramids, although most of us think of mortar and concrete as two different materials. The Great Pyramid at Giza required about 500,000 tons of mortar, which was used as a bedding material for the casing stones that formed the visible surface of the finished pyramid.

Giza,

China

About this same time, the northern Chinese used a form of cement in boat-building and in building the Great Wall. Spectrometer testing has confirmed that a key ingredient in the mortar used in the Great Wall and other ancient Chinese structures was glutenous, sticky rice. Some of these structures have withstood the test of time and have resisted even modern efforts at demolition.

Great, Wall

Rome

By 600 BC, the Greeks had discovered a natural pozzolan material that developed hydraulic properties when mixed with lime, but the Greeks were nowhere near as prolific in building with concrete as the Romans. By 200 BC, the Romans were building very successfully using concrete, but it wasn’t like the concrete we use today. It was not a plastic, flowing material poured into forms, but more like cemented rubble. The Romans built most of their structures by stacking stones of different sizes and hand-filling the spaces between the stones with mortar. The Colosseum was completed 1,937 years ago, and it stands today as one of the enduring symbols of the Roman Empire—and more literally as a testament to the endurance of Roman concrete.

Colloseum

The Pantheon

Built by Rome’s Emperor Hadrian and completed in 125 AD, the Pantheon has the largest un-reinforced concrete dome ever built. The dome is 142 feet in diameter and has a 27-foot hole, called an oculus, at its peak, which is 142 feet above the floor. It was built in place, probably by starting above the outside walls and building up increasingly thin layers while working toward the centre.

Pantheon

Middle Ages

After the Roman Empire, the use of burned lime and pozzolana was greatly reduced until the technique was all but forgotten between 500 and the 14th century. From the 14th century to the mid-18th century, the use of cement gradually returned. The Canal du Midi was built using concrete in 1670.Canal, Du

Industrial era

It wasn’t until 1793 that the technology took a big leap forward when John Smeaton discovered a more modern method for producing hydraulic lime for cement. He used limestone containing clay that was fired until it turned into clinker, which was then ground it into powder. He used this material in the historic rebuilding of the Eddystone Lighthouse in Cornwall, England.

Smeaton's Lighthouse

 

Finally, in 1824, an Englishman named Joseph Aspdin invented Portland cement by burning finely ground chalk and clay in a kiln until the carbon dioxide was removed. It was named “Portland” cement because it resembled the high-quality building stones found in Portland, England. It’s widely believed that Aspdin was the first to heat alumina and silica materials to the point of vitrification, resulting in fusion. During vitrification, materials become glass-like. Aspdin refined his method by carefully proportioning limestone and clay, pulverizing them, and then burning the mixture into clinker, which was then ground into finished cement.

Cement

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Australia’s six engineering wonders

Australia.

We’ve golden soil and wealth for toil;
Our home is girt by sea;
Our land abounds in nature’s gifts
Of beauty rich and rare;

We are a beautiful and diverse country, no doubt about that.  And we have some of the world’s most magnificent engineering wonders to match that. Here are six of them.

 

Sydney Opera HouseSydney Opera House

When people think of Australia, chances are they are envisioning the Sydney Opera House. With its unique shell-like roof structure, it is one of the 20th century’s most famous and distinctive buildings.  The facility features a modern expressionist design, with a series of large precast concrete “shells”, each composed of sections of a sphere of 75.2 metres (246 ft 8.6 in) radius, forming the roofs of the structure, set on a monumental podium. The building covers 1.8 hectares of land and is 183 m  long and 120 m wide at its widest point. It is supported on 588 concrete piers sunk as much as 25 m below sea level.

 

Sydney Harbour Bridge

Sydney Harbour Bridge

The Sydney Harbour Bridge is one of Australia’s most well known and photographed landmarks. It is the world’s largest (but not the longest) steel arch bridge with the top of the bridge standing 134 metres above the harbour. It is fondly known by the locals as the ‘Coathanger’ because of its arch-based design.

 

Snowy Mountains Scheme

Snowy Mountains Scheme

The Snowy Mountains Scheme is the largest public works engineering scheme ever undertaken in Australia. The scheme is nationally significant for its engineering success and as a symbol of Australian achievement. The Snowy Mountains Scheme was placed on the National Heritage List on 14 October 2016.

 

Kalgoorlie Super Pit

Kalgoorlie Superpit

The Super Pit, was Australia’s largest open cut gold mine until 2016 when it was surpassed by the Newmont Boddington gold mine also in Western Australia. The Super Pit is located off the Goldfields Highway on the south-east edge of Kalgoorlie, Western Australia. The pit is oblong in shape and is approximately 3.5 kilometres long, 1.5 kilometres wide and 570 metres deep. At these dimensions, it is large enough to be seen from space.

Adelaide to Darwin Railway

Adelaide to Darwin Railway

The Adelaide–Darwin railway is a south-north transcontinental railway between the cities of Adelaide, South Australia and Darwin, Northern Territory. Between 2000-2004 the line was extended from Alice Springs to Darwin as a Build, Own, Operate and Transfer back (BOOT) project by the AustralAsia Rail Corporation. This replaced the former narrow gauge line from Darwin to Larrimah and the narrow gauge/standard gauge Central Australia Railway from Port Augusta to Alice Springs which used a different route up to 200 km to the east. The railway has withstood many uniquely territorian disasters – floods and cyclones washing trains off the tracks, fast-growing tropical vegetation blocking the line and numerous accidents with road trains.
But despite all those setbacks the line has endured through the decade.

Collins-class Submarine

Collins class submarine

The Collins class takes its name from Australian Vice Admiral John Augustine Collins; all six submarines are named after significant Royal Australian Navy (RAN) personnel who distinguished themselves in action during World War II.  The Collins Class project was established in 1982 to provide six new Australian built submarines for the RAN. The Collins Class submarines are the second largest non-nuclear powered submarines in the world. Regarded as the best large conventional diesel-powered submarine in the world, the Collins Class are packed with high level technological and performance capability.

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Project: 538-540 Railway Parade Hurstville

The phone call went exactly like this…

Hello, George speaking…

“George… I just left Council and we are adding two extra levels on top”

But you’re forming up Level 1?

“I know… Architect will send you plans tomorrow”

Yes, but you’re in the process of forming the deck for Level 1?

“Ok cool… Architect will send you plans tomorrow… I’ll call you later”

The line went silent…

So imagine this:
• Foundations were built
• All the Basement 2 and Basement 1 structures were completed
• The Ground Floor main transfer deck was well and truly done
• And the boys on site were in the process of forming up the Level 1 slab

Suddenly we found ourselves needing to support an additional two levels of a structure that was not designed to carry an additional two levels.

This was going to be interesting, to say the least.

Using Finite Element Modelling (FEM), we were able to highlight weak areas of the existing structure that needed reinforcement as well as confirm areas that had sufficient strength to resist the new loads.

From the foundations to the supporting columns and walls to the suspended slabs, ACSES Engineers developed a total solution that enabled the extra levels to be added, while still maintaining the overall safety of the structure.

Below are some images of the carbon fibre reinforcement that were retrofitted to the soffit of the transfer slab. A terrific technology that gave us the extra strength we needed. Other strengthening works included widening and underpinning specific foundations as well as ‘beefing up’ specific columns and walls.

Shane and his team at First Class Building did an amazing job pulling it all together and the end result is a building that is safe, two storeys taller, and just about to be handed over to the various new owners.

Well done to all involved…

120332 - 538-540 Railway Parade Hurstville Image 2

120332 - 538-540 Railway Parade Hurstville Image 3

120332 - 538-540 Railway Parade Hurstville Image 4

120332 - 538-540 Railway Parade Hurstville Image 5

 

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Project: 43-45 Beane Street Gosford

ACSES Engineers are honoured to have been appointed as the Project Structural Engineer for the project located at 43-45 Beane Street Gosford. We are incredibly excited to be part of the design team that will help deliver this exceptional development on the Central Coast.

Project Specifics

  • 3 Levels of Below Ground Basements
  • 1 Level of Commercial Suites
  • 18 Levels of Residential Units

Scope of Works includes the structural design of the following by our in-house Structural, Civil and Geotechnical Engineers:

  • Shoring and Foundation Solution
  • All retaining structures
  • All concrete slabs, stairs, ramps, columns and walls

For more information please contact us anytime.

Boarding House View 43-45 Beane Street Gosford

43-45 Beane Street Gosford Iamge 2

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The world’s 10 greenest buildings

Green building (also known as green construction or sustainable building) refers to both a structure and the application of processes that are environmentally responsible and resource-efficient throughout a building’s life-cycle: from planning to design, construction, operation, maintenance, renovation, and demolition. This requires close cooperation of the contractor, the architects, the engineers, and the client at all project stages. The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort.

Here are ten of the world’s greenest buildings.

Apple Campus 2

Apple Park, Silicon Valley USA

The Apple Park campus will house 13,000 Apple employees, the equivalent of 35 fully-filled Boeing 747s. In keeping with Apple’s environmental credentials, it will be an impressively green building, with a focus on sustainability. It also boasts a $75 million gym for employees, and a carefully engineered design intended to create serendipitous interactions between Apple employees.

 

Shanghai Tower

Shanghai Tower, Shanghai China

The mixed-use skyscraper is one of the greenest commercial towers in the world today. The design of the tower’s glass facade, which completes a 120° twist as it rises, is intended to reduce wind loads on the building by 24 percent while one-third of its interior is public green space. The building is also powered by wind turbines and is built with a high percentage of recycled materials.

 

Council House 2

Council House 2, Melbourne Australia

Council House 2 (CH2) was Australia’s first building to be awarded a six-star green star design rating. Since its completion in 2006, CH2 has changed the landscape of its local area and inspired developers and designers across Australia and the world.

 

 One Angel Square, Manchester, UK

One Angel Square, Manchester, UK

An office building located in Manchester, One Angel Square achieved the highest recorded BREEAM score for a large building, making it one of the most sustainable large buildings in the world. The building has a used water recycling system and rainwater harvesting as well as passive solar building design. One Angel Square’s sustainable cogeneration heat and power plant also uses bio-fuel and waste cooking oil.

 

Manitoba Hydro Place

Manitoba Hydro Place, Winnipeg, Canada

Located in Winnipeg, Manitoba Hydro Place makes use of “passive design and natural ventilation” to make it one of North America’s most energy-efficient office buildings. The building has a geothermal system to heat and cool the building, roof gardens and triple-glazed windows. Thanks to these features, over 60 percent of energy savings have been made.

 

Bahrain World Trade Center

Bahrain World Trade Centre, Bahrain

A 240-metre-high, 50-floor, twin tower complex, Bahrain’s World Trade Centre’s most prominent green feature are the three skybridges which each hold a 225kW wind turbine, totalling to 675 kW of wind power capacity. The wind turbines are expected to provide 11 percent to 15 percent of the towers’ total power consumption, the equivalent of providing the lighting for about 300 homes. They are expected to operate 50 percent of the time on an average day.

 

One Bryant Park

One Bryant Park, New York City, USA

Bryant Park was the first high-rise building to be given LEED Platinum certification, with the Bank of America Tower, in Manhattan, being one of the world’s greenest skyscrapers. As well as having CO2 monitors, waterless urinals and LED lighting, the building also has its own generation plant that produces 4.6 megawatts of clean, sustainable energy.

 

Qatar National Convention Centre

Qatar National Convention Centre, Doha, Qatar

The Centre was built according to US Green Building Council’s Leadership in Energy and Environment Design (LEED) Gold certification standards. This takes a holistic building approach to sustainability and covers design, construction and operations. The design of the building makes the maximum use of natural light through the intelligent design of its skylights. This, together with superior insulation, reduces energy use. QNCC is designed to be approximately 32 percent more efficient compared to a similarly designed building and is fitted with over 3,500m² of solar panels providing 12.5% of the Centre’s energy needs. In 2015, QNCC was honoured to win the Best Conserving Building Award 2015 in the Hospitality sector at the Qatar Tarsheed Awards.

 

The Change Initiative

The Change Initiative Building, Dubai, UAE

The Change Initiative Building is a 4,000-square-metre shop that provides sustainable solutions in Dubai. The building has 26 technologies including solar panels and heat-reflective paint on its roof that provides 40 per cent of the building’s energy requirements. TCI’s outer structure has insulation three times more than that of a normal building while most of the materials used for the building’s interiors are recycled.

 

Masdar Institute of Science and Technology

 Masdar Institute of Science and Technology, Abu Dhabi, UAE

Located at Masdar City, the institute has been behind the engineering plans of the City and is at the centre of research and development activities. The institute’s building, developed in cooperation with the Massachusetts Institute of Technology, uses 51 percent less electricity and 54 percent less potable water than traditional buildings in the UAE and is fitted with a metering system that constantly observes power consumption.

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4 innovators changing the future of civil engineering

  1. Fastbricks Robotics is leading the way when it comes to robotic construction. They’re a robotic technology company developing and commercialising digital construction technology solutions, including the revolutionary commercial bricklaying machine, Hadrian X, showcased in the animation.  It’s the first part of a digital construction system which they believe will change the world, making housing affordable for everyone.

 2.  Apis Cor – They are the first company to develop a mobile construction 3D printer which is capable of printing whole buildings completely on site. Early this year, the first house printed using mobile 3D printing technology has been built in Stupino town, Moscow region.

3. MacRebur – Their mission is to turn waste plastic into durable road surfaces. Their patent pending product, MR6 is a conglomeration of carefully selected polymers, specifically designed to improve the strength and durability of asphalt whilst reducing the quantity of bitumen required in the mix. It is made from 100% waste materials and can be used in the making of hot and warm mix asphalts. MR6 is a truly unique way of enhancing asphalt to give a cost effective and longer lasting asphalt solution.

4. Hendrik “Henk” Marius Jonkers inventor of self-healing concrete containing bacteria. As solid and reliable as concrete structures may seem, they share one common enemy: tension. Over time, concrete will crack and deteriorate. An invention by Delft University microbiologist Hendrik Jonkers offers an innovative approach to creating more stable concrete by adding limestone-producing bacteria to the mix. This self-healing bio-concrete aims to provide a cheap and sustainable solution, markedly improving the lifespan of buildings, bridges and roads.

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Leading Solar Suburbs

There are 22 postcodes in Australia where half or more of households have rooftop solar PV with the majority in Queensland and Western Australia. The suburbs of Baldivis (Western Australia; 69% uptake), Elimbah (Queensland; 63% uptake) and Tamborine (Queensland; 57% uptake) are leading the way with installations on houses. Suburbs with high levels of rooftop solar PV have generally low to medium income levels and tend to be located in the outer metropolitan “mortgage belt”, or in regional areas.

leading solar suburbs

Some new suburbs are now being built with 100% solar. For example, Denman Prospect in Canberra will be the first suburb in Australia to require a minimum of 3kW of solar PV on every house (Canberra Times 2015). Breezes Muirhead in Darwin being developed by Defence Housing Australia plans to include a 4.5kW solar system and charging points for electric vehicles on each house – features which are anticipated to save residents over $2,000 a year on their electricity bills (Renew Economy 2015).

Other recent developments include the largest residential “virtual power plant” in the world, which went live in March 2017 in Adelaide (AGL 2017). The virtual power plant is made up of numerous individual solar battery systems installed in homes. The batteries store excess solar energy to use when required and the virtual power plant will sometimes help support the electricity grid by providing stored electricity to power the home or to feed back into the grid. 1,000 batteries are expected to be installed across Adelaide by the end of next year (AGL 2017).

Meanwhile, in Western Australia, Horizon Power has run a successful trial of solar and battery storage in remote locations, providing reliable power, with more systems to be rolled out by the end of the year (ABC 2017a).

Source: climatecouncil.org.au

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