a brand of Finnish Transport Agency Guidelines for the inspection of underwater engineering structures + case study

Transcription

1 a brand of Finnish Transport Agency Guidelines for the inspection of underwater engineering structures + case study Nord PIANC Stockholm Kari Pohjola

2 WHO? Work was ordered by Finnish Transport Agency FTA takes care of public fairway infrastructure in Finland, like bridges, canals, ferry harbours and AtoNs FTA orders inspections and maintenance works for these structures FTA is leading property owner to develope specifications and standards in this field Work was done by group of consultants working with these inspections

3 WHY? FTA is leading maritime infrastructure property owner to develope specifications and standards in this field in Finland New techniques has been developed with new advantages Existing specifications and standards includes almost only diving inspections Property owners are rather concervative and don t have experience about ecoustic methods when they choose inspection method

4 UNDERWATER ENGINEERING STRUCTURES Bridges Canal structures Piers, ferry berths and shore structures Fixed navigation aids

5 Examples of structures

6 DAMAGES TO STRUCTURES Weather and environmental impacts Use-related impacts Damages to materials

7 Examples of damages 1

8 Examples of damages 2

9 INSPECTION OF UNDERWATER ENGINEERING STRUCTURES Inspection system General inspection Special inspection Continuous monitoring Qualifications of inspectors Safety planning Regulations and guidelines Different parties tasks

10 Inspection periods and intervall

11 Explanations for stress classes Based on environmental effects or use of structure Examples: Bridge: Exeptional environmental stress (strong stream, floating ice, recognised risks) High environmental stress (stream, sea, probable erosion risks) Small environmental stress (not stream) Quays: High environmental stress and use (ferry quays with regular traffic and similar in sea conditions) Ordinary environmental stress (deep draught fairway quays in lake area, ordinary sea conditions) Small environmental stress (no regular traffic, inland waters) Fixed AtoNs Important structures in sea conditions, risk for erosion Important structures in sea conditions (light houses and other big marks) Ordinar AtoNs

12 UNDERWATER ENGINEERING STRUCTURES, INSPECTION METHODS Sector Scanning echo sounding Multibeam echo sounding Documentation of echo sounding Diving inspection Comparison of inspection methods (suitability) Other survey methods

13 Inspection methods

14 Suitability for inspection methods XX= good, X= moderate, 0= not suitable

15 Results, visualization

16 DAMAGE REPAIRS Concrete structures Steel structures Wood structures Stone structures Erosion protection

17 SUMMARY FTA has taken leading role to adopt new underwater inspection methods These guidelines are a part of present practise when FTA orders underwater inspections As a first published guidelines these instructions are supposed to effect to the practices adopted by other seafront structure owners too Methods have advantages and limitations depending the characteristics of the project Combination of methods can give best results Underwater inspections reaches the new level

18 Saimaa canal a case study

19 Saimaa canal, a case study 1/5 Basic information: Saimaa canal connects lake Saimaa district to the Gulf of Finland It is partially in Russian side (land area is rented by Finnish government) Total length of canal route is 43 km and it contains 8 locks and 7 movable bridges. Difference with water levels in lake Saimaa and Gulf of Finland is 75,7 m. Ship dimensions at the moment: length/width/draft 82/12,2/4,35 m Construction years (infra) and most of the length is artificial open canal

20 Saimaa canal, a case study 2/5 Work was ordered by Finnish Transport Agency Survey, analyze and reporting by Meritaito Survey was conducted with small 6 m long survey launch Keila 1 Survey included multibeam survey and laser scanning Equipment: 400 khz Reson Seabat 7125 and Riegel laser scanner Motivation for survey: Canal is almost 50 years old and Finland and Russian have negociated 50 years extention for the renting of canal and it s land area. To document present situation of canal for infrastructure and risk management purposes: Water depths, scouring, canal slopes, structures, fixed AtoN: maintanance and future development

21 Saimaa canal, a case study 3/5 FINDIGS Scouring, sedimentation, slope conditions

22 Saimaa canal, a case study 4/5 FINDIGS Structural damages, fixed AtoNs, Hazardous objects

23 Saimaa canal, a case study 5/5 POSSIBILITIES TO UTILIZE RESULTS PRODUCTIVELY: Challange: To store gathered data in usable format at least 30 years Base material for most of future activities related to canal infrastructure Risk anlyze: where and when can you expect damages Maintenance planning, future development of canal Programming and targeting forthcoming underwater inspection needs Excellent material to understand what happens and why under the water in working canal system Lock operations, ship traffic impacts, slope conditions, collisions with structures Modelling for different purpoces f.ex. Intelligent Fairway

24 Thank you for your attention! Questions?