21_LessonsLearned,PlanningDesConstr

8/12/2019 21_LessonsLearned,PlanningDesConstr

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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


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


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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construction situations

Lima Street in Upper-Kalihi


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construction situations cont.

Booth Road in Pauoa Area


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Booth Road in Pauoa Area


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Existing Deteriorated Sewer Line to be Replaced

Akahi Street in Upper-Kalihi


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2. Lessons Learned


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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Pulaa Lane in Downtown Kalihi

l fl h d h


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U ili C fli i h i d h


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U ili C fli Ti h Fi d D h


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U ili C fli Ti h Fi d D h


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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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Documents

21_LessonsLearned,PlanningDesConstr