C – Civil Engineering (Geotechnics)

 

This information is provided as assistive only and may not be complete. The revised MCHW documents should be read to confirm the full extent of the technical changes and how they apply to particular work aspects. All liability for the use and interpretation of this information remains solely with the user.

CC 601 – Earthworks

  1. Capping requirements for pavement construction have been transferred to CC 201 Pavement foundation construction.
  2. Temporary works design decisions have been removed from CC 601. CD 601 explains that these are now required to be made by the temporary works designer.
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CC 602 – Piling and Embedded Retaining Walls

  1. CC 602, 1.1 now explicitly states that Piling and Embedded Retaining Walls shall be constructed in accordance with the ICE SPERWall except as amended by CC 602.
  2. There is a change to the requirements associated with geometry of reaction pile spacing for Static Load Testing of Piles. New clause 17.13 states “Where vertical reaction piles penetrate deeper than the test pile and the base capacity of the test pile is more than 20% of the total ultimate capacity, the centre-to-centre spacing of the reaction piles from the test pile shall be more than five times the diameter of the test pile or the reaction piles whichever is the greatest.” This differs from the requirement in SPERWall.
  3. Clause 17.9 adapts SPERWall requirements by requiring test data to be recorded additionally at the maximum load for each loading cycle.
  4. Clause 20.9 changes the requirement to submit details on the type of support fluid etc at the time of tender to at least 4 weeks prior to commencement of piling works
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CC 604 – Trenchless Installation of Underground Assets

  1. The requirement for contractor to submit method statement to the Overseeing Organisation within 14days of site work commencement has been removed from CP 604. However, the method statement is required to be recorded as part of DMRB submission (see CD 622 rev1, cl.7.7.1 item 10).
  2. Existing clause 8004.14 (type of grout to be filled between the inserted pipes and sleeves) has been removed from CP 604. The Geotechnical Design Report (GDR) contained in CD 622 rev2 section 7 clarifies the design requirements and performance outcome that needs to be achieved.
  3. Clauses on H&S requirements (Cl. 8002.1 and Cl.8003.11) have been removed from CP 604 since already covered in legislation.
  4. Clause 8005.14 (packing material between the pipe joints) has been removed from CP 604 and replaced by the more performance-based clause 2.19: “All pipes shall be installed free from defects when used in trenchless installations”.
  5. New CP 604 cl.1.5 introduces the need of National Vocational Qualification NVQ Level 2 in Directional Drilling Operations competency for Horizontal Directional Drilling operators.
  6. New CP 604 cl.1.45 requires installer to record any previously unknown assets encountered during trenchless operations for preparation of as-builts records as part of Geotechnical Feedback Report (GFR) produced in accordance with DMRB CD 622 (see CP 604 cl.1.47 which requires production of the GFR).
  7. CP 604 now includes a new cl. 1.22 to specify the baseline monitoring surveys (as standard) and the monitoring survey frequency (as a WSR). The frequency of monitoring is to be agreed at the design stage, based on the assessment done in accordance with the updated CD 622 rev2.
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CC 605 – Corrugated Steel Buried Structures

  1. New Clause 1.3 requires the specifier to list site specific constraints which are not shown on the drawings/models.
  2. The new clause 1.10 requires bolted segmental systems to be compliant with a Product Acceptance Scheme. This replaces the Type Approval Certificate.
  3. New verification clause 1.26 requires the tightening of all nuts of bolted segmental systems to be verified by applying torque stated on the Product Acceptance Scheme certificate.
  4. New clause 1.23 requires that the installation of helically wound systems and bolted segmental systems shall be in accordance with the manufacturer’s installation instructions and the Product Acceptance Scheme certificate.
  5. New clause 1.52 and 1.66 requires product verification for concrete foundations in accordance with CC 482.
  6. New clause 1.16 now links the MCHW with the DMRB by giving the options to select earthwork trench and partial trench geometry, which are defined in CD 375.
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CC 606 – Reinforced Soil and Anchored Earth Structures

  1. New clause 1.3 requires the specifier to list site specific constraints which are not shown on the drawings/models.
  2. Existing clauses 2502.5 & 2502.15 require BBA certificate for proprietary reinforcing elements and systems and for proprietary prefabricated and precast facing and capping units. These clauses are replaced by new clause 1.11 which requires Product Acceptance Schemes certification for proprietary reinforcing systems, elements and facing units.
  3. New clauses 1.20, 1.27, 1.30, 1.51, 1.79, 1.89, 1.102, 1.106, 1.117 and 1.114 require performance characteristics for reinforcing strips and anchor elements to be specified in the WSR. The design requirements defining the performance characteristics are unchanged from current practice. The change is the requirement to provide documentation.
  4. In new clauses 1.20, 1.51, 1.79, 1.89, 1.102 and 1.117 reference of 1000g/m2 for any individual test area for dip galvanised coatings has been replaced with a requirement that the coating thickness will be specified in the WSR and will be based on the design outputs. There are new verification requirements comprising testing in compliance with BS EN ISO 1461. There are new documentation requirements as required by BS EN ISO 1461.
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CC 607 – Reinforced Clay Brickwork Retaining Walls of Pocket-type and Grouted-Cavity Construction

  1. New requirement for contractor design with reference to relevant design standards (including external documents)
  2. New instruction for the specifier to list site specific constraints which are not shown on the drawings/models
  3. Requirement for 14 days or longer duration after the completion of the wall before backfilling can commence, has been replaced with requirement for mortar and concrete to achieve required strength for the wall stability before backfilling. New requirements for verification of strength before backfilling.
  4. New instructions to include mortar strength performance and specify mixes for the relevant exposure class
  5. New requirement allows both designed and prescribed concrete, provided the performance and durability requirements are met. Specifier instruction included to specify strength required.
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