T-BLOCKS SOLUTION GUIDE SOLUTION GUIDES

Transcription

1 T-BLOCKS SOLUTION GUIDE SOLUTION GUIDES

2 CONTENTS Introduction 8 Reference project 9 Ultimate Performance - Technical description 11 System performance 18 On-site implementation 23 Environmental performance 25 Our sustainability strategy 32 References 33 3

3 Our approach to construction encompasses innovative sustainable products, efficient construction systems and practical solutions. We recognise the important role we have in promoting sustainable construction by optimising our products, their use and whole life performance. This document is one of a suite that identifies specific construction solutions that can help deliver a sustainable built environment. They explore the details of each system, its performance benefits, how it can be implemented and its sustainability performance. This guide introduces T Blocks which contribute to creating a sustainable built environment that is long lasting, robust and efficient. Typical Applications Flood prevention Coastal defence Earth retention Slope stabilisation 4

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5 INTRODUCTION The need to protect coastal regions and the areas in immediate adjacency to rivers is ever increasing. The frequency and severity of flood events is rising due to the effects of climate change. In England alone it has been estimated that over 2.4 million properties are at risk of flooding from rivers or the sea, with the potential to affect the 5 million people who live and work at these properties 1. The EA report on Flooding in England 1 identified that some 200 properties are at risk from coastal erosion with an additional 2,000 identified as being vulnerable in the next 20 years. Statistics collated by the Association of British Insurers on the 2016 new year flood estimated that more that 3,000 families were required to seek alternative accommodation, a third of insurance claims came from businesses and the insurance payout is expected to reach 1.3 billion 2. The social and economic impact of flooding is significant and long lasting, along with the impact that can be had on the environment in terms of natural habit damage and destruction. Increases in flood events and flood risk are the culmination of several factors. These include climate change, deterioration of defenses, new development and changes in land use. Climate change has had a twofold effect on risk, the first is in the increase in frequency and severity of rainfall events 3, the second an increase in sea levels. As 6

6 a consequence the risk of flash flooding is increased as natural water courses are more likely to have their capacity exceeded. This is further exacerbated by urbanisation and development to accommodate an increasing population, resulting in an increased use of impervious surfaces such as pavements and buildings, which create instantaneous runoff. This runoff can add further demand on natural water courses heightening the risk of flash flooding. Around the UK sea levels have been rising due to increased global temperatures causing oceans and seas to expand and this, coupled with changes in the UK land level in relation to sea level 4 is increasing risks. Climate change predictions 4 have identified that by 2095 sea levels could rise by between 12cm and 95cm, it is these conditions, combined with increased the increased extreme weather conditions, which can lead to storm surges resulting in coastal flooding and erosion. Recent Government reports 5,6 have also highlighted that there is a not only a shortfall in the investment for new flood defences but also in the management of existing flood and coastal defences. Future defences therefore need to offer significant increases in whole life performance and must help in managing whole life costs. The use of modular concrete retaining wall structures are not only robust, offering longevity, but can also be installed with relative ease, with a minimal footprint and opportunities for reuse as demands change. Whilst initially developed for coastal and flood protection they can also be readily used for all forms of earth retention works. Advantages of the system are: - Reduced land take - Increased durability and longeviety - Simplified construction - Versatile design 7

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8 CASE STUDY TRINITY ROAD SEA WALL WHITLEY BAY Protecting a stretch of coastline to the north of Whitley Bay, the Trinity Road sea wall was at serious risk of damage due to coastal erosion. and collaboration Tarmac was able to The gradual erosion of soft boulder introduce an alternative solution to the clay cliffs to the south, resulted in the traditional rock armour and sheet pile exposure of the end of the seawall approach by using T Blocks. The project allowing the ingress of seawater to the involved the construction of 26 metre rear of the structure increasing the risk long and 6 metre high barrier at the of failure. Originally installed to provide interface between the existing sea wall protection to Trinity Road which sits atop and soft boulder clay cliffs to the south. cliffs to its rear, failure would leave the T Block not only enabled the project to road exposed and put the sole access to be delivered on budget but completed St Mary s Lighthouse, a popular tourist ahead of schedule in five rather than six attraction, under threat. weeks. This minimised disruption around Working with North Tyneside Council site, especially where access was only and the Environment Agency, Tarmac possible via a stretch of public beach that embarked on on the six week, 210,000 was required to stay open. As a modular project to deliver a coastal protection precast solution blocks were stockpiled solution to resolve the issue at Trinity on site ready for construction to avoid Road. Through open engagement vehicle movements across the beach 9

9 Trinity Road sea wall, Whitley Bay during busy times reducing safety risks to the public. Furthermore, beach take was reduced from 9 metres to only 2 metres compared to a traditional rock armour solution, with excavation requirements also reduced by 88%. Looking forward, the new coastal defence solution will require little maintenance and should protection requirements change the modular system can be rapidly expanded and realigned or even reused elsewhere. Through collaborative working Tarmac, North Tyneside Council and the Environment Agency have been able to deliver a solution which offers a long term resilient coastal defence solution. 10

10 TECHNICAL DESCRIPTION T Blocks are a precast modular system designed to simplify the construction of structures for coastal defence, flood prevention and earth retention. T Blocks are essentially cuboid in their shape but also include two cutouts on diagonally opposed corners (Figure 1), enabling interlock and facilitating a range of installation options. Each T Block is constructed of unreinforced concrete creating high deadweight characteristics which in conjunction with its interlocking characteristics facilitate make it suitable for retaining and defensive applications. The innovative design of the T Block system through its cutouts facilitates design flexibility without the requirement for additional block shapes. When constructing with T Blocks the wall structure is created by interlocking the cutouts on each T Block with the adjacent block. The interlocking of the block cutouts provides restraint in one horizontal direction and the use of two block sizes creates a stepped effect on each layer providing additional restraint, fixing each block in its location in the horizontal plane. Vertically each is unit is unrestrained allowing for any potential issues linked to differential settlement. 11

11 Alternative wall structures can be created through the stepping of interlocking cutouts to provide either a straight wall or a wall with a positive or negative rake, these can in turn be combined to provide a solution that matches a coastlines form or a that of structure for which material is to be retained. Each layer of the T Block system can either be laid directly on top of the preceding layer to give a vertical retaining wall or by utilising the interlocking cutouts sloping walls can also be constructed. As the T Block solution relies on the interlock between units and each units self weight no mechanical fixing is required between blocks. This simplifies the construction process but also enables their reuse across different schemes if required. FIGURE 1 Key application areas Coastal and river defence, including erosion control Harbour development Retaining walls Emergency works 12

12 SYSTEM PERFORMANCE As a modular concrete walling solution, T Block offers a range of improvements over a range of traditional solutions utilised for coastal defence, flood prevention and retaining wall applications. SIMPLIFIED CONSTRUCTION PROCESS With the ability to be delivered to site in its final form the T Block solution offers a simplified onsite construction methodology. Initial units are required to be craned into place onto a prepared base to create the base layer, with care taken to ensure correct positioning and alignment. Positioning of subsequent units for following layers is further simplified by the interlocking nature of the units, the process of interlocking acts as a guide for their placement in both horizontal planes ensuring that they are always correctly placed. Once placed no additional works are required to secure the units into place as this is achieved by self weight and unit to unit interlock. REDUCED CONSTRUCTION TIME As a result of the simplified process on site construction time can be reduced when compared to other more traditional retaining wall, flood and coastal defence solutions. Through the utilisation of a primarily off site construction process on site activities can be reduced to initial ground preparation and the placement of complete units. This processes minimises onsite project overheads and can also reduce the amount of disruption to the local community and minise potential closure time of beaches when used in coastal protection schemes. 13

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14 DURABILITY AND LONGEVITY Concrete naturally has a naturally low level of permeability offering a water resilient solution. This means that the material is less likely to be suffer from degradation due to the effects of exposure to aggressive conditions caused by water conditions but also abrasion due to material suspended in water. As the T Blocks solution requires no reinforcement this also removes the risk of corrosion driven degradation which is identified as cracking and spalling. As a flexible material concrete can be developed to optimise its performance to support its application in any conditions. VERSATILITY OF DESIGN Due to the innovative interlocking design of the T Block units this enables a range of different alignments and configurations. The footprint of a T Block solution can be adapted to meet and match existing revetments and land contours or utilised to create new lines of defence and retainment. Vertically each layer can constructed perpendicular from the ground or sloped through the stepping of each layer. The physical design of the T Block units can also be adapted to meet a multitude of requirements. It is only a requirement that the interlocking faces remain unaltered, leading and rear faces can be profiled or moulds can be adapted for aesthetic requirements. This can include application of different finishes or colour matching to complement the surrounding area. CIRCULAR ECONOMY As a modular concrete solution T Block effectively supports the circular economy. The modular approach enables structures to be upgraded or extended overtime responding to changing demands. If alignment or location is required to change the modular nature allows existing units to be simply picked up and relocated to their new alignment. If a scheme is no 15

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16 longer required the units can be simply removed, stored and utilised in a new scheme, maintaining and increasing each block s inherent value. Once units have reached the end of their expected design life they can be fully recycled 7 and utilised as aggregate for the construction of new schemes. RAPID RESPONSE With the increase in the unpredictability and extreme nature of weather conditions there is an increasing need to respond to issues in ever diminishing time scales. The ease and simplification of construction with T Blocks facilitates a rapid response to either support the construction of additional defenses or for the reconstruction and reinstatement of areas which have been adversely affected. As conditions and requirements change existing systems can also be adapted either through the relocation of existing units or the addition of new units due to its modular design. MAINTENANCE AND LIFESPAN In comparison with more traditional defense and retaining wall structures, such as gabion baskets, the use of T Block due to its method of implementation offers a significant reduction in maintenance and lifespan. Whilst gabion revetments offer a low cost solution they suffer from a limited life due to deleterious actions of the environment in which they have been used to protect. The baskets themselves can be easily damaged by vandalism and tampering, whilst when used in coastal or river applications abrasion and corrosion due to cyclical exposure to water (and saltwater in particular) can lead rapid degradation requiring repair or replacement 8. 17

17 LAND LOSS In coastal applications the use of the T Block solution can offer improvements in limiting land loss (Figure 4) compared to the more traditional rock armour approach 9. Typically selected for its ability to preserve beaches through wave energy dissipation, relative ease of construction and low maintenance it does require a significant land take and has been noted to cause significant damage to habits and the landscape. T Block in comparison has a reduced footprint, releasing more useable space for beaches but also minimising the amount of habits and landscape affected. In urban areas the small footprint of T Block makes it suitable to be used as a response to increased risks of river flooding and flash flooding due to extreme rainfall events. FIGURE 4 18

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19 QUALITY AND SAFETY Whilst T Blocks can be manufactured both on site and off site, the relocation of manufacturing off site enables safety and quality to be increased as production takes place in a controlled environment. Improvements in safety are also reflected on site as construction activities are reduced only requiring completed units to be craned into their final position utilising the integral lifting eyes. The factory setting enables the refinement of manufacturing to a highly controlled process where rigorous testing and quality assurance is included at every stage of manufacture, with facilities covered by quality standards certified to ISO 9001 Quality Management. 20

20 BIM OBJECTS In support of design solutions utilising T Block a BIM object has been created that enables engineers to develop and refine their designs utilising a digital version of a real world solution. The downloadable object contains individual and arrays of blocks enabling wall systems to be created as they would be constructed in practice, with all the relevant data attached enabling informed decisions to be be made on performance and application. Data held within the objects can be updated as the project progresses through concept and detailed design, to construction and installation providing a full record to support ongoing maintenance and reuse. T Blocks is one of a selection of BIM objects available from the Tarmac website. 21

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22 ONSITE APPLICATION - KEY ISSUES The utilisation of T Blocks for the construction of coastal and flood defence structures along with retaining walls require changes from traditional approaches. To support T Block s utilisation Tarmac has undertaken detailed design work with Royal Haskoning. Exact requirements are to be determined on a project by project basis, however the following identifies some key considerations. GROUND CONDITIONS T Blocks can be readily used on different ground conditions without extensive need for remedials, however it essential that the prepared ground is stable, flat and horizontal base. In cases where improvements in site stability are required the use of fills or concrete bases should be employed. In coastal applications the formation level for the base of the T Blocks should be constructed below that of the lowest recorded beach level. MANUFACTURE T Blocks are precast solutions that offer flexibility in manufacture. In order to guarantee the highest quality it is recommended that they are manufactured in our designated production facilities. In applications where there is limited access or a requirement to use locally sourced materials temporary manufacturing sites can be established close to the project site. INSTALLATION It is important that site access can be assured during the entire installation phase. When installed in coastal applications additional care should be taken to ensure that site access is maintained throughout installation and will not be affected by changes in tide levels. Each T Blocks final position is required to be checked on placement, ensuring that the top surface is level and correctly orientated. Failure to do this can result in the misalignment of following layers which will be exacerbated as layers are adding potentially resulting in the completed installation falling outside of initial specifications. 23

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24 SUSTAINABILITY Utilising a T Block modular solution offers environmental improvements in coastal, flood and retaining wall applications when used in place of traditional solutions. Resource Depletion As a concrete solution T Blocks in manufacture can make use of a range of waste and recycled materials to reduce the demand on virgin materials and minise impacts on resource depletion. Through off site manufacture in a controlled environment material quality can be highly controlled, creating a product with an effective long life in its original form or as future high quality aggregate. Land Take Employing a T Block solution over more traditional defense solutions results in a reduction the amount of land take required to provide protection. By reducing land take it is possible to achieve more value from site areas by opening up more space for development or leaving land undisturbed minimising impacts on natural habitats. 25

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26 RECYCLING The concrete industry has taken significant steps to improve its performance in terms of material reuse, reducing the depletion of abiotic resources, increasing energy efficiency and reducing carbon emissions. Significant improvements have already been achieved compared to the industry s 1990 baseline 10. With respect to material reuse and the depletion of abiotic resources, concrete readily utilises recycled and secondary materials along with cement replacements. This has enabled the industry to be a net user of waste, using 107 times more waste than it generates 10, and concrete itself is also highly recyclable 7. BES 6001 * Tarmac has achieved an Excellent rating for all its production sites and products. The independent third-party scheme assesses responsible sourcing polices and practices throughout the supply chain 11. ISO Tarmac is fully accredited with ISO 14001, having implemented Environmental Management Systems throughout our business, maintaining our commitment to reducing our environmental impact

27 SUSTAINABILITY ASSESSMENT SCHEMES Concrete can play an extended role in enabling an efficient building to be created and can contribute in a number of assessment schemes and help achieve a range of credits. CREDIT/TARGET BREEAM Man 03: Responsible Construction Practices Tarmac s Carbon Calculator has the capability to determine and provide data relating to the CO 2 arising from production and delivery of our products. Mat 03: Responsible sourcing of materials Concrete is primarily constituted of locally available materials, all concrete products produced by Tarmac are BES 6001 accredited to an Excellent standard Wst 02: Recycled Aggregates Concrete is a versatile material whose design can be readily adapted to enable the use of recycled, secondary or replacement materials. CEEQUAL Life-Cycle Assessment (LCA) Though Tarmac s Carbon Calculator a full cradle to site footprint can be generated to support the full understanding of life-cycle impacts Material resource efficiency - planning Concrete can be easily recycled and reused. We also can provide specifications for alternative solutions to reduce material Long-term flood resilience and adaptation T Blocks as a modular system can be relocated, adapted or enhanced to provide a long-term solution to flood risk. Tarmac concrete products offer the ability to conform with a wide-ranging number of assessment criteria in both BREEAM and CEEQUAL. For more information contact Tarmac sustainability team. * Our BES 6001 certificate number for our readymix concrete products is BES

28 PEOPLE PLANET Safety and health Our people Community involvement Climate change Environmental stewardship Resource efficiency PERFORMANCE SOLUTIONS Economic value Governance and ethics Communication 29 Sustainable supply chain Innovation and quality Sustainable construction

29 OUR SUSTAINABILITY STRATEGY Sustainability is about securing long-term success for our business, customers and communities by improving the environmental, social and economic performance of our products and solutions through their life-cycle. This means considering not only the goods we purchase, our operations and logistics but also the performance of our products in use and their reuse and recycling at the end of their life. By doing this, we can understand and take action to minimise any negative aspects, while maximising the many positive sustainability benefits our business and products bring. Using this whole life thinking we have engaged with our stakeholders to develop our sustainability strategy. The strategy defines the main sustainability themes and our key priorities, those issues which are most important to our business and our stakeholders. It sets out our commitments to transform our business under four main themes: People, Planet, Performance and Solutions. Building on progress already made, we have set ambitious 2020 milestone targets for each of our key priorities. These ambitious targets have been set to take us beyond incremental improvement programmes to business transforming solutions. FOUR THEMES Twelve key priorities Twelve commitments Twelve 2020 milestones Forty four other performance targets Our 2020 milestones are supported by a range of other performance targets. This hierarchy helps make it easier to build understanding, drive improvement and enables us to report progress in a meaningful and measurable way. 30

30 REFERENCES 1. Environment Agency (2009) Flooding in England: A National Assessment of Flood Risk. [ONLINE] Available at: uploads/attachment_data/file/292928/ geho0609bqds-e-e.pdf. [Accessed 27 July 2016] 2. Association of British Insurers (2016) New figures reveal scale of insurance response after recent floods. [ONLINE] Available at: New-figures-reveal-scale-of-insurance-responseafter-recent-floods. [Accessed 26 July 2016] 3. DEFRA & Environment Agency (2011) Understanding the risks, empowering communities, building resilience. [ONLINE] Available at: system/uploads/attachment_data/ file/228898/ pdf. [Accessed 26 July 2016] 4. Jenkins, G.J., Perry, M.C., and Prior, M.J. (2008) The climate of the United Kingdom and recent trends. Met Office Hadley Centre, Exeter, UK. 5. Environment Agency (2014) Flood and Coastal Risk Management (FCRM) maintenance review. [ONLINE] Available at: flood-coastal-risk-management-maintenance-review. pdf [Accessed 26 July 2016] 6. House of Commons Environmental Audit Committee (2016) Flooding: Cooperation across Government - Second Report of Session [ONLINE] Available at: cmselect/cmenvaud/183/183.pdf [Accessed 26 July 2016]. 7. The Concrete Centre (2011) Fabric for the Future. Camberley, Surrey, UK. 8. Scottish Natural Heritage [n.d] A guide to managing coastal erosion in beach/dune systems. [ONLINE] Available at: heritagemanagement/erosion/appendix_1.8.shtml 31

31 9. Scottish Natural Heritage [n.d]. A guide to managing coastal erosion in beach/dune systems. [ONLINE] Available at: heritagemanagement/erosion/appendix_1.14.shtml 10. The Mineral Product Association and The Concrete Centre on behalf of The Sustainable Concrete Forum (2015). Concrete Industry Sustainability Performance Report 8th Report: 2014 performance data. [ONLINE] Available at: Performance%20Report_eighth.pdf. [Accessed 16 February 2016] 12. Tarmac Ltd (2015). ems [ONLINE] Available at: pdf. [Accessed 27 July 2016]. 13. Scottish Natural Heritage. [n.d]. A guide to managing coastal erosion in beach/ dune systems. [ONLINE] Available at: heritagemanagement/erosion/appendix_1.16. shtml. [Accessed 26 July 2016] 11. British Research Establishment [n.d] GreenBook Live: BES 6001 The Framework Standard for Responsible Sourcing. [ONLINE] Available at: [Accessed 27 July 2016]. This catalogue is provided for information purposes only. Tarmac expressly disclaims all warranties of any kind, whether express or implied, as to the accuracy, reliability and validity of the content and accepts no liability for any loss or other commercial damages incurred as a result of using and relying on the information provided. There is no partnership between Tarmac and the companies mentioned in this catalogue. All products and intellectual property rights of these companies are only used for identification and information purposes and remain, at all times, the exclusive property of their respective owners. 32

32 Tarmac and the circle logo are registered trademarks. 3678/ FCC 0243 Tarmac Portland House Bickenhill Lane Solihull Birmingham B37 7BQ enquiries@tarmac.com TARMAC.COM 2016 Tarmac Trading Limited.