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Lessons Learned Planning, Design andConstruction of Honolulus SewerRehabilitation Projects
Stuart Ujimori, P.E.
Roy Abe, P.E. Mike Young, P.E. C&C of Honolulu Dept.
HDR|Hawaii Pacific Engineers Bowers + Kubota Design & Construction
HWEA 32nd Annual ConferenceMarch 17, 2010
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Presentation Objectives
Learn from past projects to:
Expedite projects Minimize costs
Avoid problems and change orders
Make Life Easier for Everyone!
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Challenges in Rehabilitating
Honolulus Sewer System
Narrow/congested roads with lots of utilities
Substandard 6-inch sewers
Old brittle terra-cotta sewers
Sags and damaged sewers due to poor soils
Many sewers in groundwater
1,800 miles of sewer lines!
Many Sewer Rehabilitation Challenges!
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6-inch Lines in Kalihi-Nuuanu
50% are 6-inch lines!
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Terra Cotta Lines in Kalihi-Nuuanu
65% are Terra Cotta sewers!
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Lessons Learned in Project Planning
Analyzing flows and pipe capacities
Evaluating pipe condition and problems
Dealing with 6 terra cotta lines
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1. Analyze Flows and Pipe Capacities Carefully
Calibrate computer models with actual field data
Sewer lines are not always clean
Wet weather flow data may reflect exfiltration in
leaky surcharged lines (rehabilitation reducesexfiltration, which then increases flow)
Check flow splits at manholes flow model may
be inaccurate Infiltration and inflow can be concentrated in one
area do supplemental investigations
Try to avoid unnecessary upgrade work
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Avoiding the $40 million Relief Sewer on the
Kalanianaole Highway Trunk Sewer Project
Upgrade
Kahala WWPS
Clean Trunk
Sewer
Clean Inverted
Siphon
Stop 1 mgd of
Infiltration!
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2. Determine What are the
Causes of the Problems
Find the big concentrated I/I sources
Check for problems outside the project area
Look for downstream sags anddefects that back up flow
Spend extra time to clean off the old hardgrease
Turn the 5-inch grease coated pipeback into an 8-inch pipe!
Fix the Easy to Fix big problems.
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Solving the Kapiolani Grease Problem
Partially CollapsedPipe Blocking Flow
Upstream Lines with
Heavy Grease
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3. Replacing All the 6 Terra Cotta
Lines is Too Costly
Challenges with 6 lines:
Difficult to CCTV and rehab with CIPP if have morethan 0.5 offset joint
Often in backyard easements and narrowcongested streets
Consider rehabilitating with Cured-in-Place Pipe(CIPP) if:
Slope is good (generally not much problems ifgreater than 1 percent)
Limited spot repairs required (generally not more
than three)
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Lessons Learned in Sewer Design
Alignment for new sewers
Rehabilitating cast iron sewers
Conflicts with existing utilities
Improving CIPP quality
Working hours Meeting deadlines
Obtaining good bids
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4. Consider Reconstructing
Smaller Lines in the Same Location
Advantages
Less utility conflicts and unknowns
Less excavation risks (such as rock) Fewer new manholes
Disadvantages
Need extensive flow bypass (but contractors dofigure out a way to do it!)
Expect the Unexpected in the older areas
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Utility Poles are a Pain!
Add photo
Sewer Line Under
Utility Poles!
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5. Corroded Cast Iron Sewers
Can be Rehabilitated with CIPP
Requires removal of corrosion
Chain flail tool works well
Pipe diameter wont be fully restored CIPP surface wont be smooth (but still good
enough)
Need to manage risk of collapse
Monitor cleaning with CCTV watch forexcessive infiltration
Be ready for emergency repairs!
(bypass and spot repair)
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Removing Corrosion on a Cast Iron Sewer
on Ala Moana Boulevard
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6. Try Really Hard to Obtain Timely Approvals
(Easier said than done!)
Work closely with utility and other approving
agencies
Understand their concerns Be responsive to their comments
Gain their trust
Consider special design to get over hurdles
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Special Reinforced Concrete Jacket Detail
for Water Crossing due to Inadequate Clearance
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7. Improving Cured-in-Place Pipe (CIPP)
Rehabilitation
Dont require CIPP liners to be thicker thannecessary
Adds unnecessary cost
More wrinkles and more difficult to install Check initial work to catch problems early
Check work crew qualifications (new workers)
Seal annular space between liner and host pipe(stop migration of roots and infiltration)
Fix heavy infiltration to ensure resin will reach
curing temperature
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8. Seek Extended Working Hours
Consider night work to help businesses
and traffic
Allow extended hours in residential areas Do traffic studies to justify extended hours
For Kalanianaole Highway trunk sewer project,
DOT allowed different hours for east bound andwestbound traffic and weekends.
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9. Do Things to Help Meet Deadlines
Start design earlier Negotiate design work early.
Put some pressure on reviewing agencies but be
nice to them! Focus on getting the traffic control plans approved
Dont forget DCABs approval
Check and obtain required easements
Prepare archaeological monitoring plans ifnecessary
Dont forget the NPDES Construction Activity permit(if more than one acre)
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10. Getting Better Bids
Avoid year-end avalanche of projects being bid out
Break large projects into smaller ones
Many small contractors are competitive, hungry and
competent $4 to $8 million per project seems to be a good range
Consider separating out easier open trench work fromspecialty work (microtunneling and work in groundwater)
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Lessons Learned Construction ofHonolulus Sewer Rehabilitation Projectsfocused on Kalihi-Nuuanu Sewer Rehabilitation Project
HWEA 32nd Annual ConferenceMarch 17, 2010
Mike Young, P. E.
Bowers + Kubota Consulting
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Too Many Aloha Shirts & Hard Hats
Standing Around!
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Presentation Outline
1. Description of the Kalihi-Nuuanu Sewer RehabilitationProject
2. The Lessons Learned = The challenges and issuesencountered during construction are what teach thelessonso Hope that the designers can consider these lessons to improve
future designs
o Help other CMs to effectively deal with these challenges andissues if or when encountered
3. Ideas to consider for making Open Cut Trench Work Easierin the Future
What are you talking about?!?
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1. Kalihi-Nuuanu Sewer Rehabilitation Project
About Project (Short Description):
Approximately 19,500 linear feet (3.7 miles) of sewer lines, ranging
from 6 to 12 inches in diameter were installed or replaced via
open-cut trenching throughout the Lower Nuuanu and Kalihi Areas
9 separate phases/contracts with six different contractors awarded
contracts
Total Contracted Construction Amount is approximately $51
Million
Currently 6 of the 9 phases are substantially complete or being
closed out (about 80% of the overall work complete)
Wow, thats a lot of sewer pipe!
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2. Lessons Learned
Challenges and Issues Encountered
Utility Locate and Record Drawing informationsometimes incorrect or records not available This can create costly bids and dangerous situations in the field
Do the research and go through the proper utility reviews Include Descriptions of Critical Underground System information on the
plans
Verify that Contractor Calls for Utility Locates and for a Utility Inspectoras Required
Contractor can appropriately prepare for encountering the utility Contractor can be held responsible for damage to the utility
Digging in the Dark!
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Utility Locate and Record Drawing information
sometimes incorrect or records not available
Contractors hoe-ram penetrated *Major UndergroundUtility System not located per record drawings
*Specialized System causing repairs that cost over $1 Million
and caused our contractor to pull off job for several months
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2. Lessons Learned
Challenges and Issues Encountered
Work in Easements presents unusual/difficult
situations
Public Relations Work is very important (Can we start
during design). This project was a rush.
Consider Bid Items for Specific Restoration Work (In this
contract the work is incidental to other items)
Youre going to do what in my yard!
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Work in Easements presents unusual/difficult
construction situations
Lima Street in Upper-Kalihi
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Work in Easements presents unusual/difficult
construction situations cont.
Booth Road in Pauoa Area
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Work in Easements presents unusual/difficult
construction situations cont.
Booth Road in Pauoa Area
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Work in Easements presents unusual/difficult
construction situations cont.
Existing Deteriorated Sewer Line to be Replaced
Akahi Street in Upper-Kalihi
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Work in Easements presents unusual/difficult
construction situations cont.
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2. Lessons Learned
Challenges and Issues Encountered
Utility Conflicts, Tight Fits, and Damage to the sewer system
from other Utilities
Boring of holes for Utility Poles, and installation or concrete jacketing
of other utilities are sometimes the culprit of damage to the Cityssewer system
Tight Utility Crossings even more tight due to upsizing of new line
Ask the question of whether it is feasible to put the pipe back in the
same location
Easier said than done!
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Utility Conflicts, Tight Fits, and Damage to the
Sewer System from other Utilities
School Street at Stillman Lane
8
l fl h d h
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Utility Conflicts, Tight Fits, and Damage to the
Sewer System from other Utilities
Pulaa Lane in Downtown Kalihi
l fl h d h
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Utility Conflicts, Tight Fits, and Damage to the
Sewer System from other Utilities
Pulaa Lane in Downtown Kalihi
U ili C fli i h i d h
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Utility Conflicts, Tight Fits, and Damage to the
Sewer System from other Utilities
Pulaa Lane in Downtown Kalihi
U ili C fli Ti h Fi d D h
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Utility Conflicts, Tight Fits, and Damage to the
Sewer System from other Utilities
Pulaa Lane in Downtown Kalihi
U ili C fli Ti h Fi d D h
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Utility Conflicts, Tight Fits, and Damage to the
Sewer System from other Utilities
Kuakini Street
d f k h k
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3. A Few Ideas for Making the Work Easier in
the Future
Seek Permitting for Night Work in Commercial and Industrial Areas Noise a Factor
Contractor can work with minimal traffic impacts and inconvenience to public
Contractor can work more efficiently
Produce Accurate Record Drawings
Push Contractors (with CM verification) to maintain and provide accurate recorddrawings
Consider requiring contractors to provide Record Drawings in CAD
Consider walking the site with a CM or Contractor
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HWEA 32nd Annual ConferenceMarch 17, 2010
Recommended