Whitchurch Bridge Approach Road

Transcription

1 Approach Road Addendum to Report for Highway Widening On behalf of The Company Project Ref: 36466/ Rev: 0 Date: March 2017 Office Address: Caversham Bridge House, Waterman Place, Reading, Berkshire RG1 8DN T: +44 (0) E: reading@peterbrett.com

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3 Contents 1 Introduction Overview Existing Site Conditions Proposed Route Constraints Walkway Options Options Considered Benefit and Issues Summary... 5 Appendices Appendix A Drawing 36466/2007/001 J:\ \Reports\Addendum to iii

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5 1 Introduction 1.1 Overview A report outlining four options for the highway on the approach to Whitchurch bridge was issued in September Following this the option of including a pedestrian walkway adjacent to the highway over private land was suggested by the public and PBA were approached by the client to look into the feasibility of this option. This report therefore sets out the feasibility of this solution. J:\ \Reports\Addendum to 1

6 2 Existing Site Conditions 2.1 Proposed Route The proposed route of the walkway is across private land, within a doctors surgery located to the South East of the bridge. The existing footway to the bridge is narrow and difficult to navigate safely, particularly with a wheelchair or pushchair The new route would avoid a section of existing footway, which could then be closed and the highway widened locally. The section to be closed is as shown on drawings 36466/2007/001 and 002 in Appendix A to this report. 2.2 Constraints Existing trees within the site provide some constraints to the proposed routes Drawing 36466/2007/001 indicates a route that minimises the effect on existing trees. Drawing 36466/2007/002 indicates an alternative straighter route, that requires removal of more trees. However, the one tree with a Tree Protection Order has been avoided in both options There is an existing gas governor at the south end of the proposed walkway as it leaves the highway. An enquiry has been sent to the gas company regarding costs/feasibility of moving or leaving it in place and the response is still outstanding. J:\ \Reports\Addendum to 2

7 3 Walkway Options 3.1 Options Considered We have considered various options for the foundations, piers and super structure of the proposed walkway, in the context of the surroundings and likely engineering constraints. The positioning of the walkway has been a balance between the potential damage to the tree routes and likely visual intrusion for the doctors surgery, which following advice from the client has been given a higher priority. We also understand that the proposal is likely to be visually sensitive and have therefore considered the merits of both steel and timber construction The foundations of the walkway will need to be constructed in an environment close to existing trees and within flood plain. Our recommendation is to use steel helical piles as these can be installed with minimal disruption to the landowner and will reduce the risk of tree root damage within the root protection areas compared with other options. Some clearance of the existing tree canopy will be required to provide suitable headroom to the equipment required for installation It is also proposed to use steel piers as these will provide a 120 year design life and are considered as the most appropriate solution in this location The superstructure can be constructed in steel or timber. The main difference is the design life. If the superstructure is constructed in hardwood timber then its design life would be anticipated to be around 40 years, steel would provide a 120 year design life (subject to maintenance painting). Note that it would be possible to retain the steel piers in the event of the timber superstructure requiring replacement and then just replacing sections or all of the deck Slight variations on the walkway options could be as follows:- - Steel parapets - Wooden parapets - Higher parapets to provide screening to the doctor s surgery building. - Steel deck plate with appropriate non slip surfacing - Timber deck (also with appropriate non slip treatments) - Lighting (and possibly CCTV surveillance) if required J:\ \Reports\Addendum to 3

8 3.2 Benefits and Issues Summary of Benefits and Issues In the schedule below the main benefits and issues for the walkway are considered:- Benefits Walkway provided off highway alignment, giving safer and more pleasant environment for pedestrians. Enables local widening of highway through removal of existing footway. Lower number of trees affected compared to highway widening options, with associated benefit to ecology. Site is easily accessible for construction of helical piles, and this form of construction should cause minimal disruption to private land owners and bridge users. The visual impact of the walkway itself is minimal as it will be shrouded by existing trees. Main Risks / Issues Flood compensation (and associated consents / approvals) required, (although this issue needs to be discussed with the EA). Third party land agreement required. Screening required to surgery building Gas governor in close proximity to southern end of proposed walkway. May require relocation/protection during works. Maintenance to underside of structure and piers will require access to private land. Structures are more expensive to maintain than options considered in the main report. Risk of localised root damage to significant trees. Lighting likely to be required for walkway, perhaps at additional cost when compared to existing walkway. J:\ \Reports\Addendum to 4

9 4 Summary This report has considered an additional option for the widening considered for the West of the Bridge. The main constraints considered for this option have been the position of mature trees and visual intrusion for the existing doctors surgery In order to further progress the development of this solution the next recommended steps are:- Liaison with the doctors surgery over the purchase of the land and use of their access during construction Commission a further more detailed topographical survey in order to finalise the alignment of the walkway Liaise with third parties such as the Environment Agency and Local Authority with regards to planning Following receipt of the information regarding the gas governor, assuming that the costs mean that the feasibility of this option remains then it is recommended that liaison is commenced with the Local Authority in order to obtain their views on all the options considered. J:\ \Reports\Addendum to 5

10 Appendix A Drawings 36466/2007/001 and 002 J:\ \Reports\Addendum to

11 166 W H I T C H U R C H B R I D G E HIGH STREET (B471) RIVER THAMES SHOOTERS HILL (A329) WHITCHURCH BRIDGE PANGBOURNE WORKING MENS CLUB RIVER THAMES PANGBOURNE MEDICAL PRACTICE ADVENTURE DOLPHIN PANGBOURNE STATION Keyplan Not to Scale STATION ROAD WHITCHURCH ROAD (B471) THE SQUARE READING ROAD (A329) KEY TO TREE QUALITY / LOCATIONS : ROOT PROTECTION AREA (RPA) RPA OF TREE AT RISK FROM WORKS RPA OF TREE TO BE REMOVED HIGH QUALITY MODERATE QUALITY R I V E R T H A M E S 1500 NOTES: LOW QUALITY 1. DO NOT SCALE FROM THIS DRAWING 2. NO DETAILED DESIGN HAS BEEN COMPLETED FOR THIS OPTION. SCHEME SHOWN IS CONCEPT ONLY AND FURTHER DETAILED DESIGN IS REQUIRED. THIS SCHEME IS FOR FOOT TRAFFIC ONLY. 3. ALL DIMENSIONS ARE IN MILLIMETRES UNLESS NOTED OTHERWISE. ROOT PROTECTION ZONE ALL LEVELS ARE IN METRES AND RELATIVE TO ORDNANCE DATUM (NEWLYN). 5. INFORMATION ON THE EXISTING TREES HAS BEEN TAKEN FROM A TREE SURVEY COMPLETED BY TREE WORK ENVIRONMENTAL PRACTICES IN THE TOPOGRAPHICAL SURVEY WAS COMPLETED BY ATKINS IN TREE OF LOW QUALITY TO BE REMOVED THE GEOMETRY DEPICTED IN THIS DRAWING HAS BEEN DETERMINED FROM THE FOLLOWING: THE DEPARTMENT FOR TRANSPORTATION / HIGHWAYS ENGLAND DESIGN MANUAL FOR ROADS AND BRIDGES. FOOTBRIDGE IN ACCORDANCE WITH BD29/04. HIGHWAYS ENGLAND INTERIM ADVICE NOTE IAN 195/16 8. SUPPORT POSITIONS TO BE CONFIRMED INDICATING ONLY AS SHOWN. TREE WITH PRESERVATION ORDER Shed FOUNDATIONS HAVE BEEN LOCATED TO MINIMISE IMPACT ON HIGH AND MODERATE CATEGORY TREE ROOT PROTECTION ZONES : B W H I T C H U R C H R O A D The Boathouse Surgery THE NUMBER OF FOUNDATIONS SITUATED WITHIN THE ROOT PROTECTION ZONE OF HIGH AND MODERATE CATEGORY TREES TO BE KEPT TO A MINIMUM EXISTING GAS GOVERNOR - RELOCATION / RETENTION OPTIONS CURRENTLY BEING INVESTIGATED 1500 SECTION OF EXISTING FOOTWAY TO BE CLOSED TO FOOT TRAFFIC PLAN ON PROPOSED PEDESTRIAN LINK BRIDGE 1:200 The Dolphin Adventure Centre EXISTING FOOTWAY ILLUSTRATIVE 1.15m HIGH TIMBER PARAPET 1:42 1%+CLIMATE CHANGE ANNUAL EXCEEDENCE PROBABILITY FLOOD LEVEL = 40.57m A.O.D EXISTING FOOTWAY GROUND LEVEL LOCALLY RE-GRADED GROUND LEVEL LOCALLY RE-GRADED ILLUSTRATIVE STEEL HELICAL PILE EXISTING GROUND LEVEL EXISTING ARCH UNDER ROAD ELEVATION ON PROPOSED PEDESTRIAN LINK BRIDGE 1:200 P02 CLIENT COMMENTS INCORPORATED GCP NJH SCW P01 FIRST ISSUE GCP NJH - Mark Revision Date Drawn Chkd Appd 2000 SCALING NOTE: Do not scale from this drawing. If in doubt, ask. UTILITIES NOTE: The position of any existing public or private sewers, utility services, plant or apparatus shown on this drawing is believed to be correct, but no warranty to this is expressed or implied. Other such plant or apparatus may also be present but not shown. The Contractor is therefore advised to undertake his own investigation where the presence of any existing sewers, services, plant or apparatus may affect his operations. Drawing Issue Status FOR INFORMATION EXISTING MODERATE CATEGORY TREE (BEYOND) 1%+CLIMATE CHANGE ANNUAL EXCEEDENCE PROBABILITY FLOOD LEVEL = 40.57m A.O.D NON-SLIP SURFACE (`HI-GRIP EXCEL' OR SIMILAR) FSC CERTIFIED HARDWOOD TIMBER BEAM DECK, SURFACE AND PARAPET WHITCHURCH ROAD IMPROVEMENTS OPTION D PROPOSED OFFLINE PEDESTRIAN FOOTWAY LINK BRIDGE ALTERNATIVE (1) Client PAINTED STEEL PIERS (120 YEAR SERVICE LIFE) ILLUSTRATIVE CROSS SECTION 1:50 ILLUSTRATIVE STEEL HELICAL PILE Company Date of 1st Issue Designed Drawn GCP GCP A1 Scale AS SHOWN Drawing Number Checked Approved NJH SCW Revision 36466/2007/001 P02 Offices throughout the UK and Europe Peter Brett Associates LLP READING Tel: user name: andrew allen File Location: j:\ whitchurch bridge\cad\dwgs\ ped footbridge feasibility\ p02.dwg

12 HIGH STREET (B471) RIVER THAMES SHOOTERS HILL (A329) WHITCHURCH BRIDGE PANGBOURNE WORKING MENS CLUB RIVER THAMES PANGBOURNE MEDICAL PRACTICE ADVENTURE DOLPHIN PANGBOURNE STATION Keyplan Not to Scale STATION ROAD WHITCHURCH ROAD (B471) THE SQUARE READING ROAD (A329) R I V E R T H A M E S 1500 ROOT PROTECTION ZONE W H I T C H U R C H B R I D G E KEY TO TREE QUALITY / LOCATIONS : ROOT PROTECTION AREA (RPA) RPA OF TREE AT RISK FROM WORKS RPA OF TREE TO BE REMOVED HIGH QUALITY NOTES: MODERATE QUALITY LOW QUALITY 1. DO NOT SCALE FROM THIS DRAWING 2. NO DETAILED DESIGN HAS BEEN COMPLETED FOR THIS OPTION. SCHEME SHOWN IS CONCEPT ONLY AND FURTHER DETAILED DESIGN IS REQUIRED. THIS SCHEME IS FOR FOOT TRAFFIC ONLY. 3. ALL DIMENSIONS ARE IN MILLIMETRES UNLESS NOTED OTHERWISE. 4. ALL LEVELS ARE IN METRES AND RELATIVE TO ORDNANCE DATUM (NEWLYN). 5. INFORMATION ON THE EXISTING TREES HAS BEEN TAKEN FROM A TREE SURVEY COMPLETED BY TREE WORK ENVIRONMENTAL PRACTICES IN TREES OF LOW QUALITY TO BE REMOVED 6. THE TOPOGRAPHICAL SURVEY WAS COMPLETED BY ATKINS IN THE GEOMETRY DEPICTED IN THIS DRAWING HAS BEEN DETERMINED FROM THE FOLLOWING: THE DEPARTMENT FOR TRANSPORTATION / HIGHWAYS ENGLAND DESIGN MANUAL FOR ROADS AND BRIDGES. FOOTBRIDGE IN ACCORDANCE WITH BD29/04. HIGHWAYS ENGLAND INTERIM ADVICE NOTE IAN 195/16 8. SUPPORT POSITIONS TO BE CONFIRMED INDICATING ONLY AS SHOWN. TREE WITH PRESERVATION ORDER Shed CLASH WITH TREE OF MODERATE QUALITY - PROBABLE REMOVAL REQUIRED CLASH WITH ROOT ZONE OF TREE OF MODERATE QUALITY B W H I T C H U R C H R O A D CLASH WITH TREES OF MODERATE QUALITY - WOULD REQUIRE REMOVAL The Boathouse Surgery EXISTING GAS GOVERNOR - RELOCATION / RETENTION OPTIONS CURRENTLY BEING INVESTIGATED 1500 CLASH WITH TREE OF HIGH QUALITY - WOULD REQUIRE REMOVAL SECTION OF EXISTING FOOTWAY TO BE CLOSED TO FOOT TRAFFIC CLASH WITH TREES OF MODERATE QUALITY - WOULD REQUIRE REMOVAL PLAN ON PROPOSED PEDESTRIAN LINK BRIDGE 1:200 The Dolphin Adventure Centre 2000 EXISTING MODERATE CATEGORY TREE (BEYOND) 1150 NON-SLIP SURFACE (`HI-GRIP EXCEL' OR SIMILAR) P01 FIRST ISSUE - ALTERNATIVE STRAIGHT ROUTE AJA NJH SCW 1%+CLIMATE CHANGE ANNUAL EXCEEDENCE PROBABILITY FLOOD LEVEL = 40.57m A.O.D. FSC CERTIFIED HARDWOOD TIMBER BEAM DECK, SURFACE AND PARAPET Mark Revision Date Drawn Chkd Appd SCALING NOTE: Do not scale from this drawing. If in doubt, ask. UTILITIES NOTE: The position of any existing public or private sewers, utility services, plant or apparatus shown on this drawing is believed to be correct, but no warranty to this is expressed or implied. Other such plant or apparatus may also be present but not shown. The Contractor is therefore advised to undertake his own investigation where the presence of any existing sewers, services, plant or apparatus may affect his operations. PAINTED STEEL PIERS (120 YEAR SERVICE LIFE) Drawing Issue Status FOR INFORMATION ILLUSTRATIVE CROSS SECTION 1:50 ILLUSTRATIVE STEEL HELICAL PILE WHITCHURCH ROAD IMPROVEMENTS OPTION D PROPOSED OFFLINE PEDESTRIAN FOOTWAY LINK BRIDGE ALTERNATIVE (2) Client Company Date of 1st Issue Designed Drawn NJH AJA A1 Scale AS SHOWN Drawing Number Checked Approved NJH SCW Revision 36466/2007/002 P01 Offices throughout the UK and Europe Peter Brett Associates LLP READING Tel: user name: andrew allen File Location: j:\ whitchurch bridge\cad\dwgs\ ped footbridge feasibility\ p01.dwg