HBM Platforms

  • View
    220

  • Download
    0

Embed Size (px)

Text of HBM Platforms

  • 8/11/2019 HBM Platforms

    1/43

    Guidance on the use of HBM in workingplatforms

    Project code: AGG79-06

    Date of commencement of research: August 2005Finish date: March 2006

    Written by:Hilary Skinner, Andrew Dunster, Rachel Harrex, Flavie Moulinier(BRE)

    Published by:

    The Waste & Resources Action ProgrammeThe Old Academy, 21 Horse Fair, Banbury, Oxon OX16 0AHTel: 01295 819900 Fax: 01295 819911 www.wrap.org.uk WRAP Business Helpline: Freephone: 0808 100 2040

    August 2006

    ISBN: 1-84405-285-0

    Creating markets for recycled resources

    R & D R e p o r t :

    A g g r e g a

    t e s

  • 8/11/2019 HBM Platforms

    2/43

    Added value of using new industrial waste streams as secondary aggregates 1

    Executive SummaryThis document is concerned with the use of hydraulically bound material (HBM) in working platforms used in a variety ofcivil engineering and building projects.

    Stabilising land with the use of lime, cement or other binders to produce HBMs is now an extremely cost effectivemethod of converting weak soils into construction materials. Virtually any soils found on site can be improved using theHBM process for bulk fill or building applications. By using 'on site' soils or materials, construction can be carried outmore cheaply and quickly. In addition, use of site won materials can lead to significant savings in lorry movements andreductions in the environmental damage that this causes to the surrounding area. Ultimately, this also reduces the needfor quarrying and for landfill. Soil stabilisation therefore offers the potential for reduced environmental impacts otherwiseassociated with the extraction of primary aggregates, transportation of materials and landfilling.

    A working platform provides a safe and sufficiently durable working surface from which construction plant, such as pilingrigs and cranes can operate. Platforms are essential when in situ soils give insufficient support, and good design canensure maximum efficiency of construction processes. Clear economic and environmental benefits can be derived fromthe use of platforms, particularly where increased use can be made of either site-won or recycled materials when platforms can be used and re-used for a variety of purposes throughout the construction process

    when platforms can be re-used for permanent works.

    Examples can be found of working platforms that are utilised many times through a construction life-cycle; they mayprovide support for the ground works plant, ensure minimal degradation or improve the subsoils, act as formwork forcasting pad foundations, provide a surface for steelwork erection and act as a structural element within a floor slab orpavement.

    This is a guidance document for the use of recycled materials by means of HBM in the design, specification, installation,operation, maintenance and repair of a working platform and its subsequent reuse. Case studies can be found in

    Appendix A.

    This document has been written by BRE with extensive help from a project team comprising:Barry Chaddock (TRL)Paul Edwards (Scott Wilson Pavement Engineering)Nizar Ghazireh (Scott Wilson Pavement Engineering, formerly Tarmac)John Kennedy (JK Pavement Consulting)

    The project team were also grateful for advice and comments made by the Steering Group, comprising the project teamtogether with:Chris Harnan and Mark Jones (O'Keefe Construction, on behalf of BRITPAVE)Tony Suckling (Stent Foundations, on behalf of FPS)John Barritt (WRAP)

    Stabilisation works at the City of Manchester stadium (Britpave)

  • 8/11/2019 HBM Platforms

    3/43

    Added value of using new industrial waste streams as secondary aggregates 2

    Contents1. Introduction 3 2. Site conditions 8 3. Design 12 4. Platform Construction 18 5. Operation, Maintenance and Repair 21 6. Use for and interface with permanent works (formwork, blinding, foundation for pavements etc) 23 7. Standards and references 24

    Appendix A Case studies 26

    Note on scope of this document

    The guidance seeks to avoid being over-prescriptive as this might limit the scope for innovation and the development ofcost-effective solutions. Hence the guide should be seen as an enabling document and not a code of practice .

    The guidance cannot be relied upon to limit the liabilities or responsibilities of anyone involved in thedesign, specification, installation, operation, maintenance and repair of a working platform.

    While the guidance describes good practice in general terms it cannot deal with every eventuality and site condition. Aformulation of good practice can only be of value where it is applied with careful supervision, control and monitoring ofthe platform on site under appropriate contractual arrangements. All parties have to exercise their own knowledge,experience and judgement.

  • 8/11/2019 HBM Platforms

    4/43

    Added value of using new industrial waste streams as secondary aggregates 3

    1. Introduction

    1.1. Introduction Working platform definition Recycling, reuse and conservation of materials Scope of guidance

    A working platform provides a safe and sufficiently durable working surface from which construction plant, such as pilingrigs and cranes can operate. The expression working platform is restricted in this guidance to ground-supported workingplatforms, including not only the platform itself but also the associated ramps and accesses.

    A working platform supporting piling plant (Stent Foundations)

    Platforms are essential when in situ soils give insufficient support, and good design can ensure maximum efficiency ofconstruction processes. Clear economic and environmental benefits can be derived from the use of platforms,particularly where use can be made of either site-won or recycled materials when platforms can be used and re-used for a variety of purposes throughout the construction process when platforms can be re-used for permanent works, and if not recycled for other site use.

    Use of site won materials can lead to significant savings in lorry movements and the environmental damage that thiscauses to the surrounding area. This also reduces the need for quarrying and for landfill with their associatedenvironmental impacts.

    Sites with soft, waterlogged subsoil before and after stabilisation (O'Keefe Soil Remediation)

    Examples can be found of working platforms that are utilised many times through a construction life-cycle; they mayprovide support for the ground works plant, ensure minimal degradation or improve the subsoils, act as formwork for

  • 8/11/2019 HBM Platforms

    5/43

    Added value of using new industrial waste streams as secondary aggregates 4

    casting pad foundations, provide a surface for steelwork erection and act as a structural element within a floor slab orpavement. The case studies within this project (see project report) highlight the re-use of working platforms originallyplaced for the ground works plant later in the construction works and for permanent elements.

    The guidance seeks to avoid being over-prescriptive as this might limit the scope for innovation and the development ofcost-effective solutions. Hence the guide should be seen as an enabling document and not a code of practice. Theguidance does not in any way limit the responsibilities of those parties involved in the design, specification, installation,operation, maintenance and repair of a working platform.

    While the guidance describes good practice in general terms it cannot deal with every eventuality and site condition. Aformulation of good practice can only be of value where it is applied with careful supervision, control and monitoring ofthe platform on site under appropriate contractual arrangements. All parties have to exercise their own knowledge,experience and judgement.

    1.2. Introduction to hydraulically bound materials (HBM) HBM CBM In situ and ex situ mixing

    Stabilisation using hydraulic binders can improve the strength and durability of otherwise less suitable materials. Assuch, they offer the opportunity to produce working platforms that are sufficiently strong and durable that they can bereused many times during a construction project and could potentially form part of the permanent works.

    This guidance covers the key issues related to working platforms constructed using stabilised materials. In this guidance,these comprise hydraulically bound materials (HBM), mixtures that set and harden by hydraulic reaction. HBMs includecement bound materials (CBM i.e. mixtures based on the fast setting and hardening characteristics of Portland Cement)and hydraulically bound mixtures based on slower setting and hardening binders made from industrial by-products suchas pulverised fuel ash (PFA) and granulated and ground granulated blastfurnace slag (GGBS) 1.

    Throughout this report the added hydraulic component is known as a binder. Different binders can have slightly differenteffects that are dependent on the specific soil stabilised, and the correct mixture is part of the design process. HBMmixtures can rapidly dry out and significantly strengthen many weak soils.

    HBM construction is well known and versatile in terms of availability of plant and materials. HBM can be produced byeither ex situ or in situ methods. Soils or granular materials can be mixed with hydraulic binder in a stationary mixing plant and the resulting HBM

    placed and compacted by non-specialist plant. Plant for laying and compaction of HBM is similar to that required forlaying and compacting other paving materials such as unbound layers or bituminous bound products. The mixingprocess can be carried out using a "fixed plant" or "mobile plant".