managing construction schedules

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’


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.”


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


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)


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


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 Horseshoe Project – Lane Rental Fee Charges:


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


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 Horseshoe Project – Example Lane Rental Fee Charges: Work Completed that evening:


Dallas Horseshoe Project


Multiple Crews Mobilized During a Freeway Closure


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


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


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?


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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)


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)?


X Has Claim Digger been used to compare this schedule with

previous updates?


X Are there no other concerns with the schedule?


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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.


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.


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

managing construction schedules

Documents