managing construction schedules
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Dallas District October 10, 2017
MANAGING CONSTRUCTION SCHEDULES
Kelly Selman, P.E.
Dallas District
Date
Dallas District October 10, 2017
Types of Schedules
2
Contract Time Schedule
–A+B Bidding
–Lane Rental
Preliminary Schedule
Project Baseline Schedule
Progress Update Schedule
Time Impact Analysis
Dallas District October 10, 2017 3
Importance of Contract Time Schedule
FHWA Definition:
“Contract time is the maximum time allowed in the contract for
completion of all work contained in the contract documents”
When Contract Time is “Too short”
– Impacts on bid prices from inefficiency to schedule resources,
procure materials, etc.
When Contract Time is “Too long”
– Inconvenience to the traveling public from construction
activities taking ‘forever’
Dallas District October 10, 2017 4
8.3 Computation of Contract Time for Completion
“The number of working days is established by the Contract. For Contracts
with work orders, the number of working days is established in each work order.
Working day charges will begin when work begins as prescribed in Article 8.1.,
“Prosecution of Work.” Working day charges will continue in accordance with the
Contract.
Upon request, the Engineer will provide the conceptual time determination schedule
to the Contractor for informational purposes only. The schedule assumes generic
resources, production rates, sequences of construction and average weather
conditions based on historic data. The Department will not adjust the number of
working days and milestones, if any, due to differences in opinion regarding any
assumptions made in the preparation of the schedule or for errors, omissions, or
discrepancies found in the Department’s conceptual time determination schedule.”
Dallas District October 10, 2017 5
Contract Time Determination (CTD) Guidelines
Based on full evaluation of all factors involved:
–Complexity of the project
–Typical contractor organization likely to bid on the
project
–Sequence of construction
–Traffic impacts
–Local field and weather conditions
Overriding factor:
–Project completion urgency
Dallas District October 10, 2017 6
Essential Elements of a CTD Schedule
Scope of work
– Identify the scope of work for scheduling needs
Establish production rates
– Standard rates of production activities
– Adaption of rates for specific projects
Establishing constraints
– Procurement / fabrication of long lead items
– Needs of the adjacent businesses / communities that will impact the work
– Restrictions on nighttime work
– High profile events
– Sequencing work to avoid obstacles (utilities, oil wells)
Dallas District October 10, 2017 7
Essential Elements of a CTD Schedule (cont.)
Impacts of lane-closure restrictions on scheduling and logic
Calendars
–Allow contractors flexibility to work 6 days
Seasonal limitations
–Weather, temperature, daylight hours, etc.
–Letting month, start of the construction activities
Affects from adjacent projects
–Third party construction projects, i.e., city projects
Dallas District October 10, 2017 8
Minimizing Impacts on Traffic: Lane Rental Fees
for Lane Closures Use lane rental fees and liquidated damages for lane closures on construction
projects as appropriate
Establish Time periods in the contract for different volumes of traffic
• Time Period A = Peak hours of traffic
• Time Period B = Midday volumes
• Time Period C/D = Lowest traffic volumes (typically overnight or weekends)
– Time Period A lane closures are not allowed, but a dollar value is assigned in
the event that an overnight lane closure is not picked up on time. These do not
come out of the bank balance, but are deducted monthly from the estimate as
liquidated damages.
Dallas District October 10, 2017 9
Dallas Horseshoe Project – Lane Rental Fee Charges:
Dallas District October 10, 2017 10
Minimizing Impacts on Traffic
- Lane Rental Fees for Lane Closures
Dallas Horseshoe Project Example:
– Full westbound I-30 closure from 11pm Friday to 8am Saturday (9 Hours):
• 9 hours of Time Period C
• 9 x $5,048 = $45,432
– Full northbound I-35E closure from 10pm Friday to 6am Saturday (8 Hours):
• 3 hours of Time Period C
• 5 hours of Time Period D
• (3 x $5,048) + (5 x $2,019) = $25,239
– Total lane rental fees deducted from the bank balance = $70,671
Dallas District October 10, 2017 11
Minimizing Impacts on Traffic
- Lane Rental Fees for Lane Closures
Dallas Horseshoe Project:
– Work Accomplished in 8 / 9 Hours:
• Set 7 Tx62 girders over westbound I-30
• Set 8 Tx62 girders over northbound I-35E
• Placed temporary shoring and work platforms
• Removed bridge overhangs
• Removed existing high mast illumination pole
• Placed 1000 lf of portable concrete barrier
Enhanced work volume from lane closures
Dallas District October 10, 2017 12
Dallas Horseshoe Project – Example Lane Rental Fee Charges: Work Completed that evening:
Dallas District October 10, 2017 13
Dallas Horseshoe Project
Dallas District October 10, 2017 14
Multiple Crews Mobilized During a Freeway Closure
Dallas District October 10, 2017 15
A + B Bidding: Dallas Experience
• For 3 out of 4 contracts, the “A” part of the bid was under the Engineer’s cost
estimate
• For 4 out of 4 contracts, the “B” part was under the Engineer’s duration estimate
• Competitive bidding yields optimization of cost + time savings
• A+B encourages potential bidders to develop carefully developed execution plans
for achieving cost-time optimization
• The road users and the traveling public benefit from both time and cost savings
Summary - DAL A+B Projects
Letting
YearCounty
Job
#CCSJ # Daily RUC $
# of
Bids
A
(Bid Items $)
Time
Estimate
(Days)
B
(Days ×
DRUC $)
A
(Bid Items $) % O/U (A)
Time
Estimate
(Days)
% O/U (B)
Jan. 2017 Ellis 3002 0172-08-053 $3,300 7 $71,229,336 730 Days $2,409,000 $61,704,500 -13% 687 Days -6%
May. 2017 Dallas 3004 0261-02-074 $20,000 11 $59,686,407 702 Days $14,040,000 $59,011,998 -1% 468 Days -33%
Jun. 2017 Dallas 3001 0196-03-268 $50,000 5 $72,032,008 780 Days $39,000,000 $78,786,039 9% 618 Days -14%
Jul. 2017 Denton 3013 2054-02-015 $4,000 7 $36,799,470 690 Days $2,760,000 $35,041,150 -5% 650 Days -6%
Eng. Estimate Winning Bid
Dallas District October 10, 2017 16
Baseline Schedule – The Contractor’s Plan of Work
Prepared by the Contractor and reviewed by TxDOT staff for compliance
Must include all contract work
Must follow the Traffic Control Plan
Must have proper calendars including added weather days, holidays, etc.
Clear and logical critical path / longest path
Long lead / Fabricated items included
Use the full number of contract days
– A+B resolves issues with contract days
Dallas District October 10, 2017 17
Monthly Schedule Updates
Follows the approved Baseline Schedule
Ensures the schedule is updated to show all work that
has been completed
Calendars updated to show actual days worked
Review logic changes – Did they affect the Critical Path?
Use of Constraints – Is the schedule overly constrained?
Dallas District October 10, 2017 18
Sc
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Dallas District Review Checklist for Monthly CPM Schedule Updates
CSJ: 1234-56-789 Schedule Name: IH-35E (Denton)-08
Highway:
IH 35E
Data Date:
8/31/2017
County: Denton Reviewer: Tom Smith
Contractor: ABC Contractor Review Date: 9/26/2017
Yes No N/A Item Comments
X Is the schedule a separate file from the original detailed
(baseline) schedule file (or any other previous schedule files)?
X Is the schedule calculated using retained logic?
X
Is there a hammock activity to calculate contract time and is it
associated with a calendar that accurately reflects how time
will be charged?
X
If the schedule shows a change in TCP, has a formal request
letter been submitted?
X
If the schedule is a "revision" as defined in the specifications, has
a written request by the Contractor been submitted non-work and
approved?
X Are calendars set up logically, and do they consider non-work
holidays and weather?
X Do activities use appropriate calendars?
X
Have the calendars been updated to reflect actual days
worked/not worked?
X Are activities properly coded and/or can the schedule be
organized logically using the coding structure?
X
Have resources been updated to reflect actual conditions and
is resource loading fully implemented?
X Is/are the critical path(s) clearly discernable and accurately
identified?
X Is the use of constraints kept to a minimum and is there no
imposed finish date?
X
Other than start and finish activities, do all activities have
predecessors and successors?
See attached comment #1
X Are there no new/deleted activities? (if no, list) See attached comment #2
X If there are new/deleted activities, are they justifiable?
X
If there are any new activities, have the appropriate
calendars, activity codes, and resources been associated?
Have the relationships been edited accordingly?
X
Do the actual start and actual finish dates correspond with the
dates the work was performed in the field? (especially for
critical activities in this schedule or previous schedules)
See attached comment #3
X
Are the percentages complete calculated using the given
production rates?
X If there is any out of sequence work, is it acceptable? See attached comment #4
X
Has there been no gain/loss in time since the last schedule
update (use PSSR form; investigate and document the cause
for any gain/loss)?
See attached comment #5
X Has Claim Digger been used to compare this schedule with
previous updates?
See attached comment #6
X Are there no other concerns with the schedule?
Dallas District October 10, 2017 19
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Exhibit "B"
Project Schedule Status Report Project: STP 2017(083) MM County: Denton
CSJ: 1234-56-789 Contractor: ABC Contractor
Contract Days: 442 Workweek: 6 Day
Schedule Name
Data Date
Completion
Date
Working
Days
Rem
Duration
Percent
Complete
Calendar Days Working Days Days Granted by TxDOT
Explanation for Loss/Gain Period
Gain/Loss
Cumulative
Gain/Loss
Period
Gain/Loss
Cumulative
Gain/Loss
Calendar
Days
Working
Days
0196-01-1 20-Feb-17 1-Aug-18 444 0 0 0 0 0 0 Baseline Schedule Submittal (Not approved)
0196-01-2 6-Mar-17 11-Aug-18 442 0 0 0 0 0 0 Baseline (Rev 2) Schedule Submittal (Approved)
0196-01-2017-04
30-Apr-17
27-Dec-18
531
509
0.53%
-138
-138
-89
-89
The project lost 89 workdays due to the delay in pipe delivery for
the waterline, added activities, and the change in schedule logic
by the contractor in which the Phase 1 Step 1 SB Frontage
Roadwork could not begin until the waterline was installed.
IH35E-2017-05
25-May-17
27-Dec-18
531
509
0.90%
0
-138
0
-89
No Change this update period.
IH-35E (Denton)-17-1
26-Jun-17
13-Dec-18
518
451
1.80%
14
-124
13
-76
The project gained 13 workdays due to the contractor beginning
to install the new water line sooner than previously planned last
update period.
IH-35E (Denton)-07
31-Jul-17
28-Jan-19
554
459
5.62%
-46
-170
-36
-112 The project lost 36 workdays due to the procurement of the new
water line valves.
IH-35E (Denton)-08
31-Aug-17
27-Feb-19
580
458
6.69%
-30
-200
-26
-138
The project lost a total 26 workdays this update perior due to the
1) lack of progress on the new water line - 8 days; 2) the
contractor making schedule logic changes to the water line
installation - 13 days; and 3) the contractor adding a new water
line installation activity (Activity No. A18950 - Install Water
System Sta. 10-12 - New Water System) - 5 days.
Schedule Name: The unique filename assigned to the original schedule, updates and revisions.
Data Date: The calendar date when the project has been updated and the network revised, statussed or progressed.
Completion Date: The unconstrained, unrestricted calculated project completion date as calculated by Primavera Project Planner (P6).
Working Days: Calculated by P6 using a hammock activity and with an updated calendar reflecting actual time charges.
Period Loss/Gain: The number of calendar days or working days the project completion date has been delayed (positive figures) or accelerated in current period.
Cumulative Loss/Gain: The total number of calendar days or working days the project completion date has been delayed or accelerated since the original schedule.
Days Granted by TxDOT: Enter the contract days added by Change Order.
Dallas District October 10, 2017 20
Time Impacts Analysis
Contractor submits a Notice of Potential Impact and utilizes the 4-Step
process
Step 1 – Establish the Status of the project before the impact.
Step 2 – Predict the effect of the impact on the schedule.
Step 3 – Track the effects of the impact on the schedule
Step 4 – Establish the status of the project after the impact.
All four steps must be completed to analyze the impact on the project.
Dallas District October 10, 2017 21
Summary
Scheduling is a tool to help achieve project objectives and meet the public’s
expectations for timely project delivery
– Ensure accurate documentation of project progress
Engagement of the AO and District staff in:
– Developing/reviewing contract time schedules
– Reviewing Baseline schedules
– Reviewing progress update schedules
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