Simple and Cost Effective Methods of Manhole Rehabilitation. Sacha Tetzlaff WWOA Annual Conference October 20, 2010

Transcription

1 Simpe and Cost Effective Methods of Manhoe Rehabiitation Sacha Tetzaff WWOA Annua Conference October 20, 2010

2 Presentation Overview Why worry about MH I/I and deterioration? Types of Probems Commony Found Basic or Minor Probems Simpe, cheap and easy fixes Compex or Major Probems Reativey simpe to compex, but more expensive fixes

3 Budgetary and Capacity Concerns Cost to transport and treat Need bigger more expensive pump stations and WWTPs Power costs More chemica use due to diution More equipment wear and tear Sit, sediment, and grit issues Erosion eads to manhoe faiures

4 WWTP Process Concerns Hydrauic overoading and short-circuiting High fows may require process changes incuding having more treatment tanks in service Reduces water temperature Sediment reduces tank capacity Less effective BPR

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6 Sources and Causes of Manhoe Leaks and Deterioration Cover and sea Under frame/casting Joints, cracks & hoes Pipe seas Root penetrations Hydrogen sufide corrosion Groundwater eve Traffic oading/impact Freeze/thaw cyces

7 Manhoe Cover Infow Estimations Water Head Bearing Surface Over Cover Ony conceaed pickhoes; no gasket (gpm) Infow (gpd) One 1.5-inch Open Infow (gpd) Pick Hoe (gpm) 1/16 inch 10 14, ,400 ¼ inch ½ inch 12 17, , , ,360 1 inch 17 24, ,440 4 inch 23 33, ,600 *Data taken from 1976 Neenah Foundry Company s A Report on Infow of Surface Water Through Manhoe Covers 20 manhoes with 1.5 inch open pick hoe and ¼ inch of water over them = 432,000 gpd

8 Infitration Estimations Type of Leak Sow Drip Fast Drip Steady Dribbe 1/16 Inch Stream 1/8 Inch Stream Drinking Fountain Stream ½ Inch Garden Hose GPM GPD ,200 *Compied from coections of data by Nationa Power Rodding, Inc. and Strand Associates, Inc. 50 manhoes with 1/16 inch stream eaks = 20,000 gpd

9 Important Factors to Consider Genera ocation and eevation of the area surrounding manhoe Low-ying area Recessed manhoe Drainage pathways Proximity to curb Cracked pavement Wetand, ake, waterway Surrounding surface materia Nearby trees and roots

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11 Common Manhoe Probems Many very simpe probems Covers Pick hoes Gaskets/seaing Manhoe ocation and eevation Deterioration Cracks/gaps Mortar eroded Beginnings of structura faiure Commony in upper portion of manhoes Reativey easy and inexpensive to fix

12 Covers and Gaskets Pug open pick hoes or repace covers Use gasketed covers (repace gaskets) Provide for good seaing

13 Are Your Covers Effectivey Seaed?

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15 Common Manhoe Probems (cont.) Many simpe probems Location/eevation Offsets Deterioration in chimney Few minor infitration eaks

16 Some Simpe Soutions Chimney seas Barre joint seas Concrete patching Grouting Rebuid upper portion of manhoe Raise to, or above, grade

17 Chimney and Barre Seas Cick icon to add SmartArt graphic

18 Concrete Patching and Pugging Cick icon to add SmartArt graphic

19 Grouting Cick icon to add SmartArt graphic

20 Rebuiding the Chimney

21 Common Manhoe Probems (cont.) More significant or compex probems Significant infitration Structura deterioration Hydrogen sufide corrosion

22 Some More Invoved Soutions Concrete patching Manhoe iners Corrosion protection Buid a manhoe within a manhoe Note: Mutipe methods may need to be used to achieve goa successfuy

23 Manhoe Lining Cementitious manhoe iner over brick substrate

24 Epoxy Lining

25 Cured In Pace Liner

26 Manhoe Within A Manhoe FRP Concrete

27 Juy 22, 2010 Miwaukee A spokeswoman for the pubic works department said the sinkhoe was caused when a manhoe gave way as rainwater gushed through Miwaukee s drainage system. It wi take the city at east 6 weeks to fix the sink hoe. Traffic wi continue to be rerouted during that time, Barrett said.

28 Summary Manhoes can be significant I/I source Many eaks and structura probems can be reativey inexpensive to fix Lots of repair/rehabiitation methods avaiabe Appropriate rehabiitation method and materia seection is crucia

29 Concusion Successfuy reduce I/I Prevent structura faiures, backups and overfows Save money and headaches Increase system capacity Improve WWTP process operations

30 Questions? Sacha Tetzaff Strand Associates, Inc.