Construction Observation Tips


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Construction Observation Tips

  1. 1. CONSTRUCTION OBSERVATION TIPS 2009 NCRWA Conference May 14, 2009 Kenny P. Keel, PE
  2. 2. PROCESS FOR A SUCCESSFUL PROJECT <ul><li>Construction Process Checklist </li></ul><ul><li>Pre-Design/Preliminary Project Meeting </li></ul><ul><li>Permits </li></ul><ul><li>Specifications & Details </li></ul><ul><li>Pre-Construction Conference </li></ul><ul><li>Construction </li></ul><ul><li>Final Inspection </li></ul><ul><li>As-Built Submittals </li></ul>
  3. 3. Construction Process Checklist <ul><li>Develop a checklist of steps in the construction process </li></ul><ul><li>Makes it easy for developers, contractors, staff, etc. to know what is required and when </li></ul><ul><li>Keeps you from looking unfair when enforcing your typical process </li></ul><ul><li>Ensures that requirements are not overlooked </li></ul>
  4. 4. Sample Sewer Project Flow Chart (from Pierce County, WA)
  5. 5. Pre-Design/Preliminary Project Meeting with Developer/Engineer <ul><li>Developer/Engineer should meet with Utilities Director, Town Engineer, etc. to informally discuss project to coordinate planned improvements </li></ul><ul><li>Water/Sewer Extension Contract required? </li></ul><ul><li>Unusual requirements of the utility? </li></ul><ul><li>Who will review, and how many copies of submittals needed? </li></ul>
  6. 6. Permits <ul><li>Water (NCDEH-Public Water Supply Section) </li></ul><ul><li>Sewer (NCDWQ) </li></ul><ul><li>Erosion Control (usually >1acre, but locally could be as little as 10,000 sf disturbed – DLQ or County) </li></ul><ul><li>Road right-of-way encroachment (NCDOT) </li></ul><ul><li>New driveway (NCDOT) </li></ul><ul><li>Local building, plumbing, electrical permits (County or Town) </li></ul><ul><li>Site Plan Review, Zoning Permit, Conditional Use Permit, Stormwater Review (Town) </li></ul><ul><li>OTHER – Lots of possibilities , depending on project: Wetlands (Army Corps of Engineers & State), US Fish & Wildlife, Surface Water Protection, Air Quality, Aquifer Protection, Coastal Management (CAMA), Hazardous/Solid Waste, Underground Storage Tank </li></ul><ul><li>One-Stop Permit Coordination - http:// / </li></ul>
  7. 7. Specifications & Details <ul><li>If you don’t have any, you need them </li></ul><ul><li>Can be simple & straightforward, or very complex. For example: </li></ul><ul><ul><li>Hillsborough – 4 pages total Specs plus about 15 details </li></ul></ul><ul><ul><li>OWASA – Over 200 pages plus about 70 details </li></ul></ul>
  8. 8. Pre-Construction Conference <ul><li>Make sure the contractor has a copy of the APPROVED plans & specs </li></ul><ul><ul><li>Contractors are sometimes given early copies of the plans that get revised during the bidding process </li></ul></ul><ul><ul><li>Engineering and/or Architectural firms sometimes move a project forward without waiting for all approvals, even taking bids before all permits are in place </li></ul></ul><ul><li>Exchange contact info with all appropriate parties </li></ul><ul><ul><li>Contractor – Site Superintendent and Office Support </li></ul></ul><ul><ul><li>Other Inspectors – Town, County, State, etc. </li></ul></ul><ul><ul><li>Owner/Developer </li></ul></ul><ul><ul><li>Engineer </li></ul></ul><ul><ul><li>Private Testing Laboratory Rep and/or Geotechnical Engineer </li></ul></ul>
  9. 9. Construction <ul><li>Road Projects - Drainage Structures, Sub-Grade, Gravel Base, Concrete Curb, Fine-Grade, Base-Course Asphalt, Shoulder Adjustments, Surface Course Asphalt, Storm-Water Management Inspections, etc. </li></ul><ul><li>Water/Sewer Projects – Alignment (horizontal & vertical), Erosion Control, Cast-in-place Concrete, Trenching & Shoring, Pipe bedding, Backfilling, Compaction, Seeding & Mulching, Clean-up, etc. </li></ul><ul><li>All Projects – Follow the Approved Plans. If it will not work, follow procedures for changing the plans (Consult with Contractor, Engineer/Architect, Owner, Permitting Officials. </li></ul>
  10. 10. Final Inspection & As-Built Submittal <ul><li>Inspections should occur often during construction period </li></ul><ul><li>A final inspection should not find any major issues, if inspections were performed regularly and well </li></ul><ul><li>A designated set of plans should be marked throughout construction to show deviations and adjustments </li></ul><ul><li>The record drawings must be reviewed by the contractor, inspector, and engineer to ensure that the actual installed facilities are accurately shown </li></ul>
  11. 11. POTENTIAL ISSUES <ul><li>Relationships </li></ul><ul><ul><li>Not a good thing when the contractor REALLY LIKES the Inspector </li></ul></ul><ul><ul><li>Contractors have been known to “pay off” inspectors with gifts, like liquor, food, etc. </li></ul></ul><ul><ul><li>Need to Inspect your Inspectors </li></ul></ul><ul><li>One thing intentionally done wrong to make Inspector stop looking for other issues </li></ul><ul><li>New contractors (or new to area) often scrutinized harder to establish inspector’s authority/credibility </li></ul><ul><li>People do what you Inspect, not what you Expect </li></ul><ul><ul><li>Left Photo - Aerial sewer crossing with deflection over river </li></ul></ul><ul><ul><li>Right Photo – PVC water main laid 2” from sewer force main </li></ul></ul>
  12. 12. TESTS & CONTRACTOR TRICKS/SHORTCUTS <ul><li>Contractor custom-built test rigs (typ. Pressure testing equipment) </li></ul><ul><li>Pressure Testing (Water lines & Force Mains) </li></ul><ul><li>Air Test (Gravity Sewers) </li></ul><ul><li>Vacuum Test (Manholes) </li></ul><ul><li>Sewer TV Inspection </li></ul><ul><li>Mandrel (Non-rigid piping) </li></ul><ul><li>Super Chlorination (Water line disinfection) </li></ul><ul><li>Flushing New Water Lines </li></ul><ul><li>Compaction Testing (all piping) </li></ul>
  13. 13. Sewer Line Air Test & Mandrel
  14. 14. Vacuum Test & TV Inspection
  15. 15. Water System Flushing Issues
  16. 16. THINGS TO LOOK FOR <ul><li>Proper pipe bedding </li></ul><ul><li>Proper compaction </li></ul><ul><li>SAFETY </li></ul><ul><ul><li>Utility/Owner could be held responsible by a jury if someone is injured or killed, if U/O was aware of safety issues </li></ul></ul><ul><li>Documentation </li></ul><ul><ul><li>Take lots of pictures, videos, etc. If going through private property, document its pre-construction condition very well. Private owners have rose-colored glasses when recollecting the prior condition of their property. </li></ul></ul>
  17. 17. PROBLEMS ENCOUNTERED <ul><li>Leaking Water Line Extension </li></ul><ul><li>12” DIP water line installed on bedrock </li></ul><ul><li>Service taps not backfilled well with voids under corporation stop </li></ul><ul><li>Sewer Outfall Extension Problems </li></ul><ul><li>Restrained Joint Pipe (saves the day) </li></ul><ul><li>Tree Protection Area </li></ul><ul><li>PS Bypass Blown Apart </li></ul><ul><li>Shallow Water Line and Valve in Parking Lot </li></ul><ul><li>Rusted Out PS Influent Pipe </li></ul><ul><li>Shallow PVC under Drainage Ditch </li></ul><ul><li>Eccentric Reducer placement </li></ul><ul><li>Gravity Pipe used for Force Main repair </li></ul><ul><li>Backflow Danger </li></ul><ul><li>Don’t Leave Your Truck Unattended at the Job Site </li></ul><ul><li>Clogged sink problems?? </li></ul>
  18. 18. Leaking Water Line Extension <ul><li>Private Developer Project </li></ul><ul><li>Originally PVC water line extension approved, approx. 1,200 feet </li></ul><ul><li>Found Sewer Force Main within 10 feet of proposed water after plans had been approved and construction started </li></ul><ul><li>Deal made for Town to exchange Contractor’s C900 for our DIP </li></ul><ul><li>Manufacturing defect in one section of pipe caused failure of pressure test. Hairline crack that could not be seen unless under pressure. </li></ul><ul><li>Took several days (and a claimed $24K expense) of looking for leak, exploratory digging, and damage to traffic signal equipment before leak was found </li></ul><ul><li>Since it was a manufacturing defect that could not be detected until under pressure, liability fell to manufacturer, and settlement offered </li></ul>
  19. 19. 12” DIP water line installed on bedrock <ul><li>Compaction and later construction of a road pressed water line down on sharp edge of blasted bedrock </li></ul><ul><li>Punctured water line and caused approximately 20 gpm leak for months. </li></ul><ul><li>It is best to install some clean stone as a bedding under all piping to ensure a consistent and flat base. </li></ul>
  20. 20. Service taps not backfilled well with voids under corp stop & service line <ul><li>Contractor did not backfill soil well under service taps </li></ul><ul><li>Polyethylene piping pulled out of the grip joint at the corp stop upon settlement </li></ul><ul><li>Settling caused multiple leaks in a subdivision after warranty had expired, many requiring pavement cuts </li></ul>
  21. 21. Sewer Outfall Extension Problems <ul><li>Unapproved Subcontractor performing majority of the work </li></ul><ul><li>Safety Procedures Ignored </li></ul><ul><li>Lack of Compaction or Compaction Testing </li></ul><ul><li>Silt Fencing Never Removed from Site </li></ul><ul><li>Construction Debris & Mounds of Dirt Left along Outfall </li></ul>
  22. 22. Sewer Outfall Extension Problems, continued <ul><li>Promises made & broken by sub-contractor negotiating directly with a property owner for access through a residential property </li></ul><ul><li>Sub did not hire surveyor to stake alignment, which resulted in clearing beyond the limits of the easements </li></ul><ul><li>Drainage ditch constructed at end of project period with vertical sides, dirt mounded beside ditch, and no erosion control measures </li></ul>
  23. 23. Restrained Joint Pipe (saves the day) <ul><li>Hurricane Floyd washed the road out, leaving a 70 foot crevasse. At a height of 12 feet, the 12 inch water main remained operational, under pressure the whole time due to the Romac GripRings installed on the pipe. It was the only water main serving a town of more than 11,000. </li></ul><ul><li>Good example of product working properly in extreme conditions. </li></ul>
  24. 24. Tree Protection Area <ul><li>Do you see anything wrong with this picture? </li></ul>
  25. 25. PS Bypass Blown Apart <ul><li>30”-20” HDPE Pre-fab reducer fitting failed while the line was being pressurized for a hydrostatic pressure test </li></ul><ul><li>Importance of properly designing and pressure testing bypass lines </li></ul>
  26. 26. Shallow Water Line and Valve in Parking Lot <ul><li>6” GV nut 6” below rim of the valve box </li></ul><ul><li>C-900 PVC pipe <3’ cover </li></ul><ul><li>Contractor trying to conceal improper cover by cutting the valve box off to get it to correct elevation for paving </li></ul>
  27. 27. Rusted Out PS Influent Pipe <ul><li>When tying into existing PS influent pipe, found it severely rusted away </li></ul><ul><li>Had to install a liner in the influent pipe (Change Order) </li></ul><ul><li>Importance of verifying existing conditions </li></ul>
  28. 28. Shallow PVC under Drainage Ditch <ul><li>C-900 PVC pipe had <12” of cover in the bottom of the drainage ditch </li></ul><ul><li>Installed bore with 3’ cover under road, ignoring ditch cover </li></ul><ul><li>Also installed PVC pipe under the road through the casing (plans req’d DIP) </li></ul><ul><li>Improper coverage, sub-contractor work, periodic inspection </li></ul>
  29. 29. Eccentric Reducer placement <ul><li>Eccentric reducer on wet well suction line </li></ul><ul><li>Flat side of reducer should be installed on top to avoid potential air pocket trap </li></ul><ul><li>Trapped air in reducer can cause pump cavitation, or cause the pump to not work to its full potential </li></ul>
  30. 30. Gravity Pipe used for Force Main repair <ul><li>Project to replace an Air Release Valve & vault </li></ul><ul><li>Force main pipe found was actually for gravity sewer only </li></ul><ul><li>Had to install approximately 400 feet of new pipe (Change Order) </li></ul><ul><li>Incorrect pipe was installed previously to replace corroded DIP </li></ul><ul><li>Project to solve one problem found another </li></ul><ul><li>Verify existing conditions </li></ul>
  31. 31. Backflow Danger <ul><li>Gray line (on right) goes to an eye wash. SS line goes to a Hydrogen Peroxide feed line. </li></ul><ul><li>Cheap SS check valve screwed into tee was only backflow prevention to eye wash. </li></ul><ul><li>Had to disconnect the chemical feed line and cap the tee </li></ul><ul><li>Check valve failure could result in eyes washed with Hydrogen Peroxide </li></ul>
  32. 32. Additional examples
  33. 33. Additional examples, continued
  34. 35. Inspectors - Don’t Leave Your Truck Unattended at the Job Site <ul><li>This Inspector’s truck was left at the job site when the Inspector went to lunch with others </li></ul>
  35. 36. Special Thanks to: <ul><li>Town of Hillsborough & Utilities Dept. Employees </li></ul><ul><li>Highfill Infrastructure Engineering, PC </li></ul><ul><li>Summit Consulting Engineers, Hillsborough </li></ul><ul><li>WK Dickson & Co., Inc. </li></ul><ul><li>Civil Consultants, Durham </li></ul><ul><li>Town of Cary Utilities Dept. </li></ul><ul><li>Charles R. Underwood, Inc. </li></ul>
  36. 37. THANK YOU! <ul><li>Kenny P. Keel, PE </li></ul><ul><li>Town Engineer/Utilities Director </li></ul><ul><li>Town of Hillsborough </li></ul><ul><li>919-732-1270 ext 75 </li></ul><ul><li>Fax 919-644-2390 </li></ul><ul><li>[email_address] </li></ul><ul><li> </li></ul>