Cover with focus picture 1 Cover with focus picture 2 Cover with focus picture 3 Civils Examination Framework Agreement Mark Stevens MEng Senior Civil Engineer Contents • Introduction - Myself - CEFA - Range of structures • My role within CEFA - Desktop studies - Inspection - Team - Individual Working Alone (IWA) - Assessment - Hidden critical elements (HCE) COMMS-AmeyPPT-PO-01 Jan 2014 Introduction Mark Stevens • Studied Civil Engineering and Environmental Management 2003-2008 • Jacobs 2008-2009 • Amey 2009-2014 • Aecom 2014Civils Examination Framework Agreement • Inspection of Network Rail assets • £70million annual value nationally • £10million annual value in Scotland • Approximately 5000 structures in Scotland • Approximately 100 structures assessed annually • Structures assessed every 18 years (Maximum) COMMS-AmeyPPT-PO-01 Jan 2014 Railway network COMMS-AmeyPPT-PO-01 Jan 2014 Range of structures Ballochmyle Mission Impossible Small COMMS-AmeyPPT-PO-01 Jan 2014 Large Range of structures Complex Simple COMMS-AmeyPPT-PO-01 Jan 2014 Range of structures Old New COMMS-AmeyPPT-PO-01 Jan 2014 Range of structures Just weird! COMMS-AmeyPPT-PO-01 Jan 2014 My role CEFA Desktop study • Review archive data • Reconnaissance visit Inspection • Corrosion survey • Dimensional survey • Urgent defects Assessment • Masonry • Metallic • Concrete • Timber Hidden Critical Elements (HCE) • Review archive data • Reconnaissance visit Bridge Strike Initiative (BSI) • Determine susceptible structures • Assess capacity Desktop study 1981 Track evolution 1993 2013 Desktop study Dimensional evolution Inspection Inspection Inspection – Individual working alone Inspection Pigeon Guano •Acidic causing corrosion Inspection Bridge strike resulting in buckling of flange •Bending capacity reduced Inspection Lamination of steel •Due to water penetration and exacerbated by timber •Trough sections also at risk due to water collection. Inspection Longitudinal tear in main girder •Web not critical •Beam theory may break down Inspection Holing to web over the support •Urgent defect reported •New web plate installed Inspection Pitting to the web and flange •Grit blasted and repainted •Rewaterproofed Inspection Dimensional survey •Levelling •Tapes •Callipers •Lasers •Accuracy 1/8” (3mm) can be the difference Inspection Riveted construction Inspection Welded construction Assessment Compliance with Network Rail structural codes •Ensures consistency throughout infrastructure •Ensures safety of the railway and the public at large Codes used •NR/GN/CIV/025 •NR/SP/CIV/035 Network Rail codes specify loading to be applied •BS5400:3 •BD21/01 British Standards specify capacities of elements Assessment Typical checks •Ultimate limit state. No serviceability checks •Dead load – ballast depth critical •Live load considering RA10 load vehicle at appropriate speed •Bending capacity • Compact/non compact • Effective length / Fully restrained •Shear capacity Assessment Level II analysis – refinement of initial level I assessment •Confirmation of Steel Assessment Level II analysis – refinement of initial level I assessment •Confirmation of dimensions •Reduction in safety factors •Removing schoolboy errors Assessment • Plane frame analysis to better model the load effects • Use of real vehicles HCE Stewarton bridge collapse • January 2009 • First bridge collapse in over 100 years • Ten wagon goods train carrying mixed consignment of gas oil, diesel and kerosene derailed. • 220,000 litres of diesel and kerosene leaked from freight train wagons, contaminating River Irvine and causing serious impact on the ecology of the watercourses. • Structure collapsed onto the A735, a busy road with school traffic. COMMS-AmeyPPT-PO-01 Jan 2014 HCE Stewarton bridge collapse • Shear failure mode COMMS-AmeyPPT-PO-01 Jan 2014 HCE Rail Accident Investigation Board (RAIB) • Heavy corrosion had significantly weakened the east and centre main girders. • Form of construction resulted in hidden corrosion trap which affected inner surfaces of the main girders. • Use of incorrectly assumed dimensions for the thicknesses of the web plates in previous assessments. • The lack of any action from Network Rail in response to raised Urgent Defect Report in relation to the web plate corrosion. COMMS-AmeyPPT-PO-01 Jan 2014 HCE Details COMMS-AmeyPPT-PO-01 Jan 2014 Thank You Any questions? COMMS-AmeyPPT-PO-01 Jan 2014