Precast concrete is transforming the world one project at a time.
By Sara Geer
When you hear the words, “beautiful,” “award-winning” and “life-changing,” what comes to mind? It likely isn’t precast concrete. Yet, architects, engineers and contractors around the world are choosing precast to accomplish all this and more. Precast concrete is creating housing options in London, allowing employees to keep working without disturbances in Alcalá de Guadaíra, Spain, accomplishing feats of engineering in Perth, Australia, and ensuring a healthier society for centuries to come in The Hague, Netherlands. If you’re not already a true believer in the amazing versatility and functionality of precast concrete, taking a look at these projects will be sure to change your perspective toward the world’s most exceptional building material.
London, United Kingdom
Precast’s Role in Solving London’s Housing Crisis
Anyone who follows the news knows London’s housing shortage is hitting fever pitch. For instance, Prime Minister Theresa May declared her “personal mission” in 2018 was to fix the housing crisis, which means even Britain’s top leaders are desperate to find a solution – and fast. According to statistics, 50,000 homes need to be built every year until 2025 just to keep up with demand, yet between April 2016 and March 2017 only 6,423 homes (affordable and open market) were completed. Engineers who have been working on creative and inventive ways to provide housing didn’t have to look far for the solution: precast concrete.
Engineers from WSP were commissioned by Network Rail to examine the potential for railway overbuild at sites where there was approximately 32 feet of available land on both sides of existing tracks. WSP found this footprint would allow for the development of 12-story apartments, and that if even 10% of the potential was delivered, 250,969 new homes could be provided.1 With this information, Network Rail collaborated with IJM Land in a bid to construct a new superstructure housing development comprised of three new residential towers above the Docklands Light Railway.
However, in order for this project to be successful, the rail had to first be encapsulated. The encapsulation structure needed to fulfill these conditions:
- Be built on a slope
- Protect the railway
- Provide fire and noise separation
- Ensure a robust, suspended foundation so work could commence on the development known as Royal Mint Gardens.
After much discussion, the team agreed unanimously the only way to make it happen was to use precast concrete. Contactor Careys PLC appointed Ireland-based Banagher Precast Concrete to design the precast solution. Using BIM technology, the precaster’s team of civil engineers and WSP co-designed the complicated structure to be completed in two phases.
According to Banagher, the first major structure created an extension of the existing DLR tunnel, which could withstand train impact loads. The precaster’s design called for custom precast concrete T-wall panels of various heights to meet the lines and levels of the complicated design.
“Accuracy in manufacturing the panels was paramount as they needed to fit the capping beams in-situ first time,” said Caroline Cavanagh, marketing director. “A major advantage of using these units was that they could be lifted and bolted in position quickly, meaning they were immediately stable – which was very important as they were installed on a live rail line.”
Method statements were developed and presented to Network Rail prior to installation to ensure the correct and safe installation of the walls. The panels were then manufactured and delivered to a restrictive site with limited storage space, which left no room for error in the delivery timeline.
The next phase included the installation of the complex roofing structure that was also designed by Banagher Precast using a combination of precast concrete slabs, reinforced concrete beams, MY beams and double tees.
The roofing beams were installed during a 48-hour window while the train was shut down completely. The precaster’s decision to use invisible connectors directly cast into the beams aided in a quick and safe installation. Cavanagh said the project was the first encapsulation of its type in London and was successfully completed in 2017. Since then, the precaster has completed one more project and has heard talk that more sites are being identified for development. The project won the Irish Concrete Society International Award in March 2018.
“We’re hoping that our expertise will put us to the forefront for precast solutions for this newly emerging market,” Cavanagh said.
Alcalá de Guadaíra, Spain
Work Delays a Non-Issue with Precast
Making the decision to expand an existing building is an exciting venture for a business. It presents an opportunity to build better brand recognition, build value in the business for employees and customers, and provide more space to offer a wider range of products and services to a larger market. While business leaders are working hard to make these ambitions a reality, the last thing they need is for the construction to disrupt their work. For this reason, the best construction material that can make all this happen without bringing extra headaches is precast concrete.
Architect Ingeniura pitched this idea to Best Medical Diet when designing the expansion for its Alcalá de Guadaíra, Spain, facility since precast met three conditions: create a building that identifies the business brand, expand existing facilities and get the built set identified as a unit. According to José Luque, founder and CEO of Best Medical Diet, each area of the building (design, manufacturing, administration, etc.) provides wide and open spaces to work that gives a sense of order, relaxation and naturalness.
Using the design of its architect David López Caballero, a diamond shape was chosen for the geometric unit since it adapted well to the scale of the building for the warehouse, offices and production area. In addition, the shape eased constructing the building’s corner and enhanced the business’ corporate colors.
“The material of these pieces had to be versatile and give guarantees of durability, sealing and installation ease,” López said. “Therefore, glass-fiber-reinforced concrete panels were finally chosen, which are assembled like a vertical puzzle fixed to a metallic substructure.”
Based on the successful performance shown on previous projects, they selected manufacturer Prehorquisa, located in Segovia, Spain, to provide the precast concrete pieces for the project. Founded in 1988, Prehorquisa specializes in producing custom facades with architectural precast concrete panels.
“Timing was an important issue for this project since the staff continued working during construction,” said Daniel Valle Gómez, project and sales manager. “They also wanted to incorporate a new company image with an innovative design for the building’s exterior. With precast, we were able to reduce the planning process and the disturbances to their employees while providing them exactly what they wanted.”
Valle said 370 custom-made, glass-fiber-reinforced precast concrete sandwich panels were manufactured for the building’s facade since the project architect wanted the panels to have a smooth finish. In addition, green and gray color pigments were added to the mix design to match Best Medical Diet’s branding.
The only difficulty with manufacturing the panels was ensuring the dimensions and tolerances were precise for fitting them together, especially in the corners of the building. Therefore, an anchorage rail system was attached to the back of each panel to fix the units securely in the steel structure.
“Luckily, we are accustomed to working on complex projects,” said Valle. “But, in this case, ensuring the dimensions were precise in the molds was key to this project. Thanks to our experienced production and quality control team we were able to achieve it without problems.”
The public’s admiration has been a testament to the teamwork between the engineering team overseen by Javier Carvajal and design team, which focused on dedicated quality control to create a stunning exterior addition that makes a statement for the company.
“For us, it makes us proud that a company such as Best Medical Diet trusted us to make this a reality for them, and that we can now add this awesome project as part of our portfolio,” said Valle.
A Precast Masterpiece
Music has a profound ability to both impact and express human emotions. So much so that hearing a piece of music can bring goosebumps, tears or inspire pure joy. Similarly, this awe-inspiring emotional connection likely occurred when the final touches were completed on the Cadogan Song School structure. The project is a two-story precast concrete building constructed for the choirs of St. George’s Cathedral and the Anglican Diocese of Perth, Australia.
The idea for the building was first conceived by Rev. Dr. John Shepherd (Anglican Dean of Perth from 1990 until 2014), who visited many cathedrals in the United Kingdom. As he surveyed the site of the demolished former Dean’s Vestry, he and Palassis Architects developed a plan to create a song school inspired by the St. George’s Cathedral’s lancet windows to fill the space. Since the building was to be placed within proximity of four existing buildings, three of which are heritage listed, careful attention to detail needed to be taken to seamlessly blend the building with the surrounding 140-year-old architecture and maintain clear sight lines for the Ascalon sculpture, an abstract interpretation of the story of St. George and the dragon.2
“The Song School’s design ensures that important view lines toward the Ascalon sculpture are preserved.,” said Kevin Palassis. “Locating the Song School partially underground minimizes the building’s footprint and ensures existing sight lines are maintained.”
The lower floor of the building includes precast concrete curved beams and an exposed external wall with vertical slots to provide light into the choir practice area. Then from the lower floor, U-shaped precast columns support some of the precast vaulted arches together with the units on the first floor, which forms a colonnade with stairs. On top of the vaulted units are two curved sloping precast spires.
Providing precast solutions
According to National Precast Concrete Association Australia members SA Precast and J Woodside Consulting, there was a significant amount of work involved in the pre-planning stages to rework Palassis’ original structural design to make it a workable and practical solution.
“The architect originally wanted the walls to be 3 inches thick, but it wasn’t feasible to cast them, provide the connections and transport the pieces more than 1,700 miles,” said John Woodside, who assisted SA Precast in handling and erection, and gave general engineering advice. “We advised the thinnest we could make the panels was 5 inches, which was reluctantly agreed. However, in its finished position, the thickness of the panels looks fantastic.”
He said handling the complex-shaped pieces was another concern, so lifting frames had to be designed to allow the panels to hang vertically when being erected on-site. In addition, extensive shop drawings were prepared for both the molds and reinforcement to ensure no significant issues occurred.
“Special formwork was made using computer-generated profiles for the spires,” Woodside said. “For the spire to be erected and fixed before lining and leveling, a semicircular base plate was cast into the slab beneath the spires.”
All the precast elements were manufactured using white conventional concrete with an off-form sandblasted finish.
In 2017, the project won the Kevin Cavanagh trophy, which is the highest award given to a concrete project in Australia and awarded biennially by the Concrete Institute of Australia. It has also won an Excellence Award at the Western Australian chapter of the Australian Institute of Architects and has been shortlisted by the United Kingdom-based Institution of Structural Engineers in its 2018 structural awards. With this project, Palassis Architects, J Woodside Consulting and SA Precast have teamed up to create a work of art.
“Precast concrete was the right construction material for this project, as the architect specified concrete,” Woodside said. “And, there is no other material that would have been able to provide the complex shapes the architect was looking for.”
In addition, NPCA Australia’s CEO Sarah Bachmann believes the award-winning outcome of the project is a testament to the quality of precast the association’s members produce.
“There is no doubt the aesthetic of this project is a vision to behold,” Bachmann said. “It has certainly pushed the boundaries of precast concrete and is a testament to what off-site prefabrication can achieve.”
The Hague, Netherlands
Precast Raises Society Wellness
Want the secret to living a longer life? Even with studies being released every year with new suggestions to boost your chances of living longer, evidence keeps pointing to the advice you likely got from your parents: eat well, exercise regularly, get plenty of sleep and stay away from bad habits.
With this knowledge already recognized, municipality leaders of The Hague, Netherlands, collaborated with private partners to expound on these basic building blocks to construct a sports campus in historic Zuiderpark that emphasizes the importance of sports and exercise to deliver a healthier society. While the aim was to improve public health and wellness for generations to come, every detail in the building’s design had to work together to make that possible – even down to the chosen building materials.
According to FaulknerBrowns Architects, the curved appearance of the building was formed by a simple plinth constructed from textured precast concrete panels. Manufacturer Bijlbouw incorporated a gray pigment into the mix design to attain the desired appearance, and a Reckli formliner was used during casting.
A big draw for choosing precast concrete is its many sustainable properties. The building is designed to be as compact as possible, while providing the necessary space for the range of sports and education facilities. When combined with a well-insulated precast panel exterior shell, energy loss is minimized. In addition, with the recent push by the concrete industry to reduce its carbon footprint worldwide3, the choice to use precast concrete only helps to aid the municipality of The Hague’s ambition to be carbon-neutral by 2040.
Therefore, the integration of precast concrete has helped to create an environment that celebrates and promotes the value of sports for the health and wellbeing of all.
Sara Geer is NPCA’s communications manager and is managing editor of Precast Inc.