The Site Specific Designer will be responsible for undertaking and managing the design and approvals process of the conarch bridge reconstructions as identified in the flow chart below:
Gather background record data on masonry arch overbridge geometrical parameters, e.g. skew, span, arch rise
Use initial feasibility flow chart to determine suitability of Standard
Conarch Suite Guidance from
Technical User Manual
Confirm that the bridge parameters fall within the
Standard Designs
Justify decision not to use Standard Conarch Suite to Network Rail’s Professional Head
of Civil Engineering
Use of non- standard design
accepted
Complete Technical Approval Process in Accordance with
NR/SP/CIV/003 Undertake feasibility study using
‘Conarch Calculator’ to determine layout & details of standard conarch units Guidance from
Technical User Manual
Undertake site surveys to determine design parameters, e.g. skew, span, arch rise, road alignment,
railway clearances, rail to road level difference etc Confirm that the general
parameters fall within the Standard Designs
Complete Technical Approval Process in Accordance with
NR/SP/CIV/003
Reference Standard Drawings & Details Form B. SDD do not require checking
except for suitability for use Prepare site specific drawings.
To include general arrangements and layout
drawings
Prepare site specific Health & Safety environmental and
other relevant information Prepare site specific
specifications. Refer to Network Rail model clauses
for specifying Civil Engineering Works NR/L3/CIV140
Issue drawings, specifications, Health & Safety Risk Assessment and other information and documents to
Contractor Guidance from TUM
on Standard Details
Select suitable Standard Details
Use Conarch Calculator to confirm conarch unit layout for Site Specific
structure
Select standard precast unit drawings to be used
Prepare General Arrangement Drawings
Use Conarch Calculator to generate reinforcement schedules
for the various precat units and insitu works Prepare site specific detailed design drawings incorporating
standard details NO YES NO YES NO YES
The actual responsibilities are detailed below:
7.1.
SCHEME SPECIFIC DETAILS
The Site Specific Designer will be responsible for all the site specific details including:
• Existing permanent way alignment details and any proposed changes.
• Existing highway alignment details across the bridge and any proposed changes.
• Existing abutment capacity.
• In-situ concrete schedule, and road alignment design if it doesn’t follow the Conarch
Calculator.
7.2.
STANDARD DESIGNS AND DETAILS
7.2.1. Conarch Calculator
The scheme specific designer is to use the Conarch Calculator and is responsible for:
• Generating the basic layout geometrical details of the proposed bridge
reconstruction and taking this information to produce the bridge layout drawings.
• Generating the reinforcement schedules for the precast Conarch Units and issue to
the unit manufacturer
• Generating the reinforcement schedules for the in situ concrete.
7.2.2. Standard Design Precast Concrete Unit Drawings
The following precast concrete elements of the conarch suite have been designed and design checked and a Form B issued:
• Conarch Inner Units General Arrangement and Reinforcement Detail drawings
• Conarch Edge Units General Arrangement and Reinforcement Detail drawings
• Parapet Beam and Parapet Panels General Arrangement and Reinforcement Detail
drawings
It is for the Scheme Specific Designer to:
• Use the details shown on the above drawings plus the layout information from the
Conarch Calculator to produce the layout drawings for Conarch Units.
• Provide the appropriate general arrangement and reinforcement detail drawings
with the bending schedules generated from the Conarch Calculator to the precast concrete unit manufacturer
7.2.3. Standard Detail Precast Concrete Unit Drawings
The following precast concrete elements of the conarch suite have been designed and design checked and a Form B issued:
• Generic general arrangement and reinforcement detail drawings for:
o Parapets.
o Transition Parapet Edge Support Beams.
o Cill Units.
It is the responsibility of the Scheme Specific Designer to:
• Use the standard details to produce the site specific drawings as follows;
o Parapets – The Parapet profile and panel lengths will be determined from the
proposed highway longitudinal vertical profile.
o Transition Parapet Edge Support Beams – The layout and shape of the
precast units will be determined to suit both the vertical and horizontal highway alignments.
o Cill Units – The Cill Unit width and length will be determined to suit the
skew and width of the bridge.
o Develop the generic reinforcement schedules to suit the site specific dimensions of
the above elements.
7.2.4. Standard Detail In-situ Concrete Drawings
Generic general arrangement and reinforced concrete detailed drawings for the following in-situ concrete elements of the conarch suite have been designed and design checked and a Form B issued:
• Generic general arrangement and reinforcement detail drawings for:
o Backfill Reinforced Concrete.
o Capping Slab Reinforced Concrete.
o Transition Parapet Slab Reinforced Concrete.
It is the responsibility of the Scheme Specific Designer to:
• Use the standard details to produce the site specific drawings as follows;
o Backfill Reinforced Concrete – The shape both vertically and horizontally
will be determined from the proposed highway vertical profile and skew of the bridge.
o Capping Slab Reinforced Concrete – The shape both vertically and
horizontally will be determined from the proposed highway vertical profile and skew of the bridge.
o Transition Parapet Slab Reinforced Concrete – The shape both vertically and
horizontally will be determined from the proposed highway vertical profile and skew of the bridge.
• Develop the generic reinforcement schedules to suit the site specific dimensions of
the above elements.
7.2.5. Standard Details Drawings
Generic general arrangement detailed drawings for the following standard details of the conarch suite have been designed and design checked and a Form B issued:
Generic general arrangement drawings for the following elements:
• Transition Parapet layout details.
• Waterproofing details.
• Road Surfacing details.
• Lifting Details.
• Construction Sequence.
It is the responsibility of the Scheme Specific Designer to:
• Use the standard details to produce the site specific drawings for each of the above
elements
7.3.
SITE SPECIFIC DESIGN CERTIFICATE SUBMISSION
A full site-specific Form A submission will be required for each Conarch bridge, followed by Form B excepting the design of the components and the construction details to be given in the standard Conarch drawings and supporting documents.
7.3.1. Contents Summary
Issues pertinent to the proposed use of Conarch Units are listed below and should be set out and justified in the normal way:
• The existing arch profile showing springer and crown levels with superimposed
vehicle kinematic envelopes or gauge envelope to demonstrate lack of existing clearances for the enhanced gauge.
• The proposed arch profile, showing arch springer and crown levels with
superimposed vehicle kinematic envelopes or gauge envelope to demonstrate that proposed clearance and clearance tolerance. (Note that the tolerances of the Lasersweep surveying system, Clear-route modelling software, and the normal tolerances on site setting out and construction, call for provision of 80mm clearance in addition to modelled clearance.) This shall be demonstrated by the site specific Form A submission.
• Note that the design will not conform to the structure gauges given in the Track
Design Manual NR/L2/TRK/2049, and will therefore require derogation by the Track Geometry and Gauging Engineer.
• Surveyed abutment geometry.
• Existing highway vertical and horizontal alignments.
• Existing highway cross-section including any footpaths and verges.
• Proposed vertical and transverse highway alignment and crossfall in the construction
area.
• Effects on or proposals for sight lines.
• Proposed highway cross-section and road pavement thickness including footpath and
/ or verge widths.
• Selected bridge parapet containment.
• Safety barrier and transition arrangements on the approaches.
• Selected parapet height and height extension where adopted.
• Selection of parapet construction, concrete or reinforced masonry.
• Number of precast units to provide required bridge width between parapets.
• Details of services, duct sizes and locations.
• Locations of any lighting columns and street furniture (must not facilitate parapet
climbing).
• Any requirements for fixing OLE to the structure.
• Vandalism profile of the site and appropriate provisions.
• The condition of the existing abutments, wing walls etc, any signs of distress or
undue settlement and their causes, and any requirement for repair or strengthening.
• Any historic evidence of settlement of the sub-structure.
• Any new differential settlement anticipated in the sub-structure.
• Whether the effects of dead and / or live loading on the existing substructures or
their tendency to sliding / overturning will be significantly greater than existing.
• Appropriate structural and / or geotechnical analysis carried out.
• Any underpinning, remedial work or strengthening proposed.
• Anticipated stability of existing abutments when superstructure is removed.
• Supporting drawing or drawings.
To be white before issue
ANNEXE 1 Schedul e Of St andard Dr awings ANNEXE 2 St andar d Vehicle G auges & Profil e Envel ope Sketc hes ANNEXE 3 Exc el Spread Sheet F or Envelope Pr ofiles ANNEXE 4 Conarc h Struc tur e D et ails ANNEXE 5 Conarc h Bri dge Span Varianc e Sketc h ANNEXE 6 Conarc h Bri dge D ec k Wi dt h Vari anc e Sketc h ANNEXE 7 Cons truc tion Seq uenc e ANNEXE 8 Road Ver tical Profile Envel opes ANNEXE 9 Design Ris k Asses s ment ANNEXE 10 Conarc h Calc ul at or