The following is an update from the Highways Agency and their maintenance contractor AONE, regarding the crossing of the A180. I think questions rightfully need asking as to why its been left so late for the initial contact (25th February!) and just what VM are planning on doing to speed things along. From AOne: Mr Lewis Thank you for your email concerning the above. I am handling your request under normal business practices and not in accordance with the Freedom of Information Act/Environmental Information Regulations. The Highways Agency received some preliminary information relating to Virgin Media’s proposal on 25th February 2014 from BB (UK) Ltd. This was received by our contractor Aone+. The Agencys initial review of the proposal indicated that the scheme as presently proposed presents some unacceptable fundamental risks to the Agencys assets i.e. the trunk road, and possibly other utility services in the area. Subsequently a response letter was sent to PB (UK) Ltd and Virgin Media on the 13th March 2014. This letter included advice on what was required to progress the proposal for directional drilling beneath the carriageway (A180). Unfortunately, I havent been able to attach a signed copy of that letter but have pasted the contents into this email (below) for your information. We have not heard or received any further information from Virgin Media or their contractor following our comments/advice detailed in the letter of 13th March 2014. With regard to timescales, the Agency support sustainable development and economic performance, but also must ensure any proposals do not compromise the capability of the strategic road network. And, whilst the Agency will do everything to assist Virgin Media and their contractors in this matter, it remains their Project to manage. Therefore, issues relating to timescales and having the necessary approvals is a matter for their Project team. Please note, the Agency has only received an enquiry at this stage and no formal notification has been made that would aid the formal approvals procedure? Please let me know if further assistance or information is required. Regards Steve Steven Wright, Service Delivery Manager Highways Agency | Lateral | 8 City Walk | Leeds | LS11 9AT Safe roads, reliable journeys, informed travellers Highways Agency, an executive agency of the Department for Transport. --------------------------- Date: 13 March 2014 PBU (UK) Ltd Greengate Cottage Millfield Lane West Frampton Boston PS20 1BW Att of: Wayne Cartwright Dear Sirs AREA 12 MANAGING AGENT CONTRACT Re: A180 Directional Drilling Following receipt of your enquiry in relation to PBU (UK) Limited’s proposals to undertake directional drilling beneath the A180 carriageway and our copy of the letter we issued to the Highways Agency, we have now received their comments and provide a consolidated response of our concerns. We have undertaken the review of your proposals in accordance with the Highways Agency Design Manual for Roads and Bridges Volume 4 Section 1 Part 8 HA 120/08 – “Guidance on the Trenchless Installation of Services Beneath Motorways and Trunk Roads”, and have the following comments which need to be addressed before this proposal can be formally certified by the Highways Agency. 1. Procedure · No evidence or mention that the scheme was notified to the Highways Agency via the submission of a Statement of Intent (SoI). Please provide details of the SoI if indeed one was submitted. If not, please take into account this requirement for future works. Issuing a SoI at the start of your works will aid you in the formal approvals procedure. 2. Services Little discussion has been provided regarding the risk of impacting on existing infrastructure and how to mitigate those risks, specifically: · The alignment of the proposed drill runs is almost perfectly in line with the existing highways drainage system and as such, the depths, diameters and type of drainage needs to be more fully discussed in your submission and ideally the positions and depths of the drains shown on the cross section to indicate the level of cover between the proposed directional drill and the existing drainage. · It is unclear how deep any of the services are. Strikes could lead to loss of drill fluid and potential break outs, and ultimately impact on the carriageway, as well as damaging the drainage and causing issues at a later date. · There is a Gas Valve Chamber close to the site, which is mentioned within the report, but no mention of services leading up to or from this. Please can you provide copies of the Utilities Service Providers Drawings showing their plant in the area of the proposed works? Note that a sketch line on an aerial photograph is not acceptable. · There may be other services which may be impacted by the works and as such, copies of all utilities service providers’ information should be contained within your submission to provide comfort that there is no risk of strikes. Any utilities that are present should be shown on the cross sections to indicate the proximity to the proposed bore. Based on the above, we ask that PBU (UK) Ltd undertake; · a detailed review of services in the area including highways drainage records (the HA can enable access to their own-line database) to assess risk of the drill to the services; · update the risk register with findings; and · consider undertaking a drainage survey to ascertain depth of services and whether they present a risk either as a direct strike, or in terms of settlement or heave of the services within the zone of influence. 3. General Queries/Actions In order to obtain certification, PBU (UK) Ltd also need to address the following: · Section 5.4 Recommends monitoring take place before, during and after construction. PBU (UK)) Ltd need to provide details of when and how this will be conducted. Monitoring before, during and after construction is essential, primarily to assess whether damage has been caused, the feedback into improving analysis is desirable but secondary · Risk register: This is to be updated to a format which includes: Hazard, Consequence, Impact and Risk (tabular can be very effective). Risks requiring further consideration to demonstrate they have been considered and considered negligible or have been mitigated against: · Impact to Bridge/Bridge Foundations. The risk of settlement affecting the HA bridge (supported on spread foundations) should be assessed. · Settlement of the carriageway. If the possible settlement of 10.9 mm developed over a 3.5 m length of carriageway occurs, it would probably provide unacceptable ride quality, maybe even causing speed restrictions, or possibly road closures, until the damage is repaired as part of the crossing works · Services (see above) · Presence of street furniture foundations along drill route e.g. safety barrier within central reservation, Section 6 item (vi) of the report is vague. What depths would they expect such items to be located for example? · What loads will be transferred onto the installed pipe due to traffic and confirmation that this is acceptable and will not cause collapse of the pipe and thus settlement of the carriageway · Stability of launch/reception pits and associated embankments · Environmental impact of works, e.g. clearance of trees, habitat · Confirm the material type to be used as a slurry · Risk of deflection of the bore from its proposed alignment due to encountering different material types? E.g. clay v sand. An assessment needs to be made and mitigation measures proposed. · Alignment tolerances need to be stated and details of how the alignment is to be controlled when the bore is below the carriageway should be described and agreed · Emergency procedures should be detailed for if drilling causes an incident that requires emergency action. · Heave: The main risk according to HA120/08 is heave, how will this be controlled/monitored? At 2m below carriageway level with entry and exit pits rather higher than carriageway level, break out of drilling fluid either at the ground surface or into the HA drainage appears to present an unacceptable level of risk. Enhancement of positive pressure would increase this unacceptable risk. · PBU (UK) Ltd to record the geology within the Launch/Reception pits to confirm anticipated geology. · PBU (UK) Ltd to provide an explanation on why directional drilling was selected rather than another method. · Has the local authority been informed of the works? · Update report to include relevant items from Section 7.7 of the HA 120/08, e.g. open excavation, trenchless methods, instrumentation and monitoring etc. · Cross section: TA11SE167 sand band is incorrect. Sand band was recorded up to 3.3m, not 1.7m. There is actually more clay between crown and top of sand. This also indicates there is a potential thickening northwards, raising up toward the pipe level, before potentially deepening at the reception pit? · HA120/08 Section 6. Method Statements and Emergency Procedures should be submitted to Managing Agent for review. · Has any impact of this scheme on the A180 HA Immingham road improvement scheme been considered/assessed? The above concerns need to be addressed and a formal revised submission sent directly to the Highways Agency Geotechnical Advisor for formal certification before any works will be allowed to start on site. The revised submission should be send to: Mr Dennis Sakufiwa Senior Advisor - Geotechnics Highways Agency Lateral 8 City Walk Leeds. LS11 9AT Email: [email protected] Once the revised submission has been formally signed off by the Highways Agency, PBU (UK) Ltd need to send a copy of the accepted submission and a copy of the associated signed off Geotechnical Certificate to A-one+ for our records. Yours faithfully For and on behalf of A-one+ Integrated Highway Services Craig Snow A-one+ Programme Delivery Manager Cc Sarah Blake, Virgin Media, Unit C Wellington Gate, Silverthorpe Way, Waterloville, Hampshire. PO7 7XY
Posted on: Thu, 20 Mar 2014 11:22:54 +0000
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