GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 List of key amendments included in Version MA 2.0 (14/08/2015) 1) Transfer from Excel 2003 to Excel 2010. 2) A new Assessment Menu has been added to fit with Excel 2010. 3) The Form AA0 and Form BA0 no longer contain an approved list of CREs. It is the responsibility of the Assessor to ensure each form is signed by a competent and approved person taking note that once signed the Form AA0 cannot be amended. Forms are signed using “Sign Forms” from the Assessment menu. The signatures will now be checked and approved by Network Rail Structures Managers. 4) Name and Title are now mandatory inputs on the Form AA0 and Form BA0 to facilitate approval by Network Rail Structure Managers. 5) During Data Transfer results from the original file are compared to the updated file with any changes being flagged within the Tool on an additional tab which will become visible if changes have occurred. If no changes occur the Form BA0 signatures will be carried forward. 6) A log file will be produced during Bulk Data Transfer which will show for each file if they contained Errors, Changes to the Results or Transferred without Change. This file will be saved in the output folder. 7) During signing of the Form BA0 forms, the inputs will be automatically checked to ensure no changes have been made since the calculation was run. If changes have been made, the calculation must be re-run before signing the forms. 8) Improvements to the efficiency of the tool have been made throughout. Page 1 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 List of key amendments included in Version MA 1.6 (13/04/2015) A number of minor bugs (identified by the Help Desk Queries) have been resolved. Page 2 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 List of key amendments included in Version MA 1.5 (24/01/2014) The key update within this version of the Tool is within the ‘engine’ used to determine the assessed capacity for masonry arches. The Tool output is generated from the results of a parametric study, within which thousands of ARCHIE-M assessments have been undertaken for a representative range of single span arches. To maximise the scope of the Tool for Network Rail’s arch stock, adjustment factors have been developed to apply to the single span results to account for multi span and pier slenderness effects. Within this version of the Tool, a verification exercise has been undertaken to confirm the trends with the multi-span factors and their magnitude. Further work has also been undertaken to refine the method of applying the adjustment factors (within the Tool ‘engine’), and subsequently for a number of multi span arches, this may remove a level of conservatism from the previous assessed capacities determined. The following changes have also been made as part of this update: Sheet Name Amendment Description Assmt Parameters Pier height Further guidance provided for use in the absence of record information. Arch Assmt Geometrical parameters Additional warning advise provided for short span viaducts (e.g. less than 6m span). Reference tables Assessed capacities Guidance provided for typical assessed updated capacities for example arches has been updated to reflect the current Tool. Page 3 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 List of key amendments included in Version MA 1.4 (26/07/2013) Sheet Name Amendment Description Form AA0 Question 8 Tool is not appropriate for arch profiles with a span to rise less than 2 or greater than 8 for railway and highway / footway loading. Assmt Parameters Brick counting exercises Brick on end dimensions revised. Assmt Parameters Barrel thickness Further guidance provided. Assmt Parameters Fill depth at crown Lower bound fill depths revised to 0.360m for underbridges and 0.200m for overbridges / footbridges. Further guidance provided. Bridge Condition Additional definitions added Additional drop down options available to for a range of defect differentiate between: severities  Severity B – the effect of water and spalled masonry  Severity F – bulging and displaced or missing bricks / blocks  Severity I / P – transverse cracks with or without a stepped displacement of the barrel Bridge Condition The BCMI data populated by the Assessor will generate a statement, stating the effect of the condition recorded on the arch barrel assessment, and how the Tool will provide an assessed capacity based on the current condition. Bridge Condition BCMI matrices The effect of condition revised following a review with Network Rail. Further clarity provided on type of transverse cracks observed. Effect of Condition Guidance added Clarification provided as to how the Tool considers the effect of condition. Further Guidance on Guidance added Further guidance provided on the type and Arch Defects significance of arch defects. Condition Qual Question 1.0 Transverse crack question modified to align with revised matrices. Page 4 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 Sheet Name Amendment Description Condition Qual Question 2.0 Question modified to align with revised matrices. Condition Qual Question 6.0 Question modified to align with revised matrices. Condition Qual Generated statements revised Arch Assmt Provision of a current A current condition result is provided for all condition result arches that are within the parametric range considered by the Tool. Where potentially significant defects are identified and not considered within the assessment result, warnings are provided stating the defects that have not been considered. Arch Assmt Image files Further guidance provided on the insertion of the relevant image file. Interim Guidance Appended document Interim guidance (dated May 2013) Note removed incorporated within the revised Guidance Notes (Version MA 1.4). Page 5 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 List of key amendments included in Version MA 1.3 (11/06/2013) Sheet Name Amendment Description Glossary of terms “Header” added Definition of “header” added. General Skew angle Further guidance on skew angle provided within the Guidance Notes. Condition_Qual New sheet added Where BCMI information is missing, a qualitative review of the arch condition can be made using the Tool functionality as described within the Guidance Notes. Bridge_Condition Uncracked defects A bug has been resolved to ensure that bulging/ displacement/ missing bricks defects are accounted for within the assessment. “Assessment Help” Guidance removed Guidance on the use of this function removed Menu from this document. The embedded Guidance Notes have been removed from the Tool. Interim Guidance Interim Guidance Notes Notes (dated May 2013) appended to Guidance Notes. Page 6 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 Glossary of terms Elements of a masonry arch rail overbridge (top) and underbridge (bottom) Extract from CIRIA C656 Masonry arch bridges – condition, appraisal and remedial treatment Arch barrel The (vertical) load bearing part of the arch, which contains a single thickness of voussoir stones or several rings of brickwork. ARCHIE-M An engineering tool to assist with the analysis of masonry arch bridges and viaducts. Arch extrados The topside of the arch barrel. Page 7 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 Arch intrados The underside / soffit of the arch barrel. As built The condition of the arch structure at its time of construction. Brick A masonry unit comprising a shaped and kiln-fired block of clay or shale which can be used as an element for the fabric of a bridge. As a general guide, medium strength bricks can be scratched with a key. Soft bricks can be rubbed away with a finger. Bridge A structure of one or more spans greater than or equal to 1.8m, whose prime purpose is usually to carry traffic or services over an obstruction or gap. For the purposes of this Tool, this term includes underline bridges, overline bridges, footbridges and intersection bridges. Bridge drainage The management of water on a structure, e.g. drainage channels, downpipes, weepholes etc.The management of water on a structure, e.g. drainage channels, downpipes, weepholes etc. Culvert A structure with a span less than 1.8m whose prime purpose is to permit water or services to pass under or adjacent to Network Rail infrastructure. Elliptical arch Indicating a ‘flattened’ semi-circular arch, used to keep height reasonable, to reduce approach gradients, and to increase the width of gauge clearance below. Engineering brick A dense, strong and durable brick, often used for construction or facing of engineering structures. As a general guide, such bricks cannot be scratched with a key. External support BCMI reference for end supports such as abutments. Fill depth at crown to Fill depth (including ballast) measured from the extrados of the arch underside sleeper barrel at the crown to the underside of sleeper. Haunching Structural material used to provide support behind the structure (e.g. at the arch extrados interface). Header A masonry unit laid with its longer dimension normal to the face of a wall or arch barrel, used to interconnect adjacent rings of brickwork. Internal spandrel walls Masonry wall that sits on the arch barrel (along the length of the (with voids) barrel). The area between the internal spandrel walls is voided. Internal support BCMI reference for intermediate supports such as piers. Major element BCMI reference for major asset elements including the deck, intermediate and end supports. Page 8 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 Masonry The work of a mason, commonly used to refer to work in stone or brick material. Midspan The clear distance between the support and a point at the position of span divided by 2. Minor element BCMI reference for asset sub elements including the arch barrel, face rings / voussoirs, spandrel walls etc. for masonry arch structures. Multi span A multi spanned bridge consisting of three or more spans. Parapet For the purposes of this Tool, a masonry wall that sits on top of the spandrel wall. The height of the parapet should be taken from the stringcourse level to the top of the masonry wall. Permissible speed The maximum speed allowed over a section of line that applies to trains (when not operating at an Enhanced Permissible Speed as shown within the Sectional Appendix). Pier An intermediate support between adjoining bridge spans. Pier slenderness The ratio of pier height divided by pier width. Quarter span The clear distance between the support and a point at the position of span divided by 4. Ring A layer of transverse masonry elements that form slender units to make up an arch barrel. In brickwork, multiple adjacent rings are commonly used to produce a multi ring arch. Rise Vertical height of arch intrados from the springing level. Segmental arch Arch whose intrados comprises a segment of a circle which is smaller than a semicircle. Semi-circular arch Arch with an intrados the shape of a semicircle (i.e. a 180º arc) so that the rise is half the span. Skew arch Arch where the longitudinal and transverse axes are not at right angles. Span The clear distance between supports of an individual arch along its longitudinal axis. Span to rise ratio The ratio of arch span divided by the rise of the arch at the crown. Spandrel wall Masonry wall that sits on the edge of the arch barrel and that limits the extent of, and retains, the backfill material. Springing Plane from which the arch springs, i.e. the junction between the vertical face of the abutment / pier and the arch barrel. Page 9 of 70 GUIDANCE NOTES FOR MASONRY ARCHES Level 0 Assessment Tool Version MA 2.0 Steady state A stable condition that does not change over time. Stocky piers Piers with a slenderness ratio of 2 or below. Stringcourse A (decorative) section of masonry at the interface between the spandrel wall and the parapet. Track / carriageway Distance between the nearest running rail / edge of carriageway and distance from wall the inside face of the parapet / spandrel wall. Voussoir A wedged shape masonry unit used to make an arch or vault. A number of the above definitions are taken from CIRIA C656 Masonry arch bridges – condition, appraisal and remedial treatment. Page 10 of 70