Location-based Scheduling linked to a (BIM) integrated scope-cost-schedule model in Virtual Design

and Construction (VDC)FIATECH Spring 2009

Stanford University Construction Engineering and Management Center for Integrated Facility Management

granite@stanford.eduRA: Forest Peterson

fischer@stanford.eduPI: Professor Martin Fischer

olli.seppanen@vicosoftware.comOllie Seppänen

Tomi.Tutti@tocoman.comTomi Tutti

RichSee@DigitalAlchemyPro.comRichard See

The Take-home Message:

Leveraging the properties in the Building Information Model (BIM) we expand the existing software to create the: scope takeoff, location-based schedule, cost estimate and 4D check.

What can be done now, What is still difficult, What is coming next:

An integrated system while resulting in reduced rework, data entry and risk of errors is unable to cleanly feedback the time variable quantities derived from the schedule. Next, is to investigate an open source database as a shared source of variables, parameters and constants.

Summary

First, an inaccurate plan may lead to safety issues: Issues adapted from James C. Belke Recurring Causes of Recent Chemical Accidents , U.S. Environmental Protection Agency.

1) Surrounding

2) *Fatigue

3) *Environment

4) *Rushing

5) Misequipped

Second, providing field hands with updated project support toolsis consistent with the power to the edge philosophy promoted by John Boyd, resulting in improved worksite solutions.

Importance of Location-based Schedule Updates

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Forest Peterson Stanford Construction Engineering & Management

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adjust resources, i.e., production, as needed

The material presented is in the context of Virtual Design and Construction (VDC) work at CIFE.

This method reduces wasted resources and supports green and sustainable construction practices.

With this CIFE does not just research but also educates.

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Leveraging Sharing of Information Between Software tools

6

objects: architectural,structural

milestones

time variable direct and indirect

takeoff

Scope

Cost

Schedule

resources:

L/E/M/S

production

7

overhead

FIATECH2009

Forest Peterson Stanford Construction Engineering & Management

Pro

ject

-Spe

cific

Product model

Cost model

Production library

Take-off recipe

formulas

Object library

Classification through WBS

Customizable database / knowledge

Human-computer interaction

Integrated or middleware

Formula library

Objects

Planning & setup

Implicit objects

Operations

SCOPE COSTTIME

Project

Activity library

Assembly library

Construction methodIn

tegr

ated

or

Mid

dlew

are

Inte

grat

ed o

r M

iddl

ewar

e

Inte

grat

ed o

r M

iddl

ewar

elegend

Inte

grat

ed o

r M

iddl

ewar

e

Pro

ject

-Ind

epen

dent

Process model

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Warning: Careful step by step explanation/overview of what this diagram shows before diving in

quantities

map objects

Cost ModelSage-

Timberline

Process Model

Vico Control

MiddlewareTocoman Express

Hosted ServerTocoman

Construction Model Server / Citrix

Operation ListTocoman Quantity

Manager

operations, quantities & production rates

operations combined into activities

operations, recipe formulas &

production rates

operation library

RS Means

estimator looks at product model and selects operations

Product ModelRevit

Architecture

MiddlewareTocoman Express

Link ObjectsTocoman

iLink

3 5

4

7

6

2

2

1

open CMS operation list in Quantity Manager

main sets of information

form

function

behavior

Product

Organization

Process

1. Select operations based on objects, specifications, and assemblies.2. Create implicit recipe-formulas as a function of objects.3. Compile objects into object groups. 4. Map object groups to recipe-formulas.5. Compile production rates, operations and takeoff quantities into activities. 6. Map objects to activities then check for constructability in 4D.7. Enter time values for time-dependent operations. 9

Work Breakdown Structure:Stanford CIFE WL1 WL3 & WL10 (location)

+Construction Specifications Institute CSI MasterFormat WL 4 WL6 (specification)

+AutoDesk Revit WL7 (object)

+RSMeans WL8 WL9 (operation)

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Takeoff quantities for implicit objects are derived from objects through recipe formulas.

For example, formwork is not graphically or symbolically represented in the 3D model. A takeoff quantity can be derived from the modeledconcrete objects surface area as square feet of contact area (SFCA). 12

Phase parameter6 structural workzones2 architectural workzones

Story, name parameter10 floors (inc. basement and earthwork)

In the Revit model sublocations are defined as stories and Workzones are defined as phases. The project locations are: 8 floors, 1 basement, 1 earthwork, 6 structural phases and 2 architectural phases. Total locations 8x6 + 8x2 + 1 + 1 = 66

For this project the object grouping took 2 hours to complete, including rework.

Method to match locations in Construction model Server to Revit properties defined in iLink as locations

In total for this simple Revit model:15 Revit model elements66 locationsEquals 626 individual objects require

location specified2 hours to link

Iteration of changes in the method, scope or sequence requires a new pass, resulting in:

1) a new optimization of the schedule for project constraints

2) a check of the 4D model for constructability

3) a review of the cost estimate

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Illustrates the affect of location phasing on production and which operation is the driving production rate.

Four core concepts in Location-based Scheduling (LBS): 1) one task per task type is occurring in any given location, 2) workflow locations can be completed in any order, 3) maintain minimum 1-2 days buffer between tasks, 4) use the same location sequence for all the tasks. 18

Image from team Sweden

Adding production, resources and crewing as properties in the schedule allows integrating these parameters with takeoff quantities over the project duration. Two resource concepts of Location-based Scheduling are:1) continuous resource use for each task2) use the same number of resources for a task in each location. 19

Image from team Chile

Seven key discoveries made by student teams:

1) The scope-cost-schedule planning process replicates tribal knowledge existing in construction field crews.

2) Recipe-formulas provide take-off quantities for objects implied to exist in the 3D product model.

3) The goal varies with the professional focus. Some perceived focuses are: the cost estimate, the schedule, the constructability 4D model check and the knowledge gained to efficiently build an object.

4) Slowing an activity can result in reduced project duration.

5) The quantity required for a crane, i.e., time variable cost, is measured in days, not in physical units.

6) Reduced rework and errors.

7) The write-up refines and solidifies concepts discovered through the process.

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Learning curve

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Akinci, B. and Boukamp, F. (2002). "Representation and Integration of As-Built Information to IFC Based Product and Process Models for Automated Assessment of As-Built Conditions." Nineteenth International Symposium on Automation and Robotics in Construction (ISARC 2002), September 23-25, 2002, Washington, DC, USA.

Akinci, B., Fischer, M., Levitt, R., Carlson, B. (2002) Formalization and Automation of Time-Space Conflict Analysis. Journal of Computing in Civil Engineering, ASCE, Vol 6. No. 2, 124-135

Kiziltas, S. and Akinci, B. The Need for Prompt Schedule Update By Utilizing Reality Capture Technologies: A Case Study. CII Construction Research Congress, CII, April 5-7, 2005, San Diego, CA.

Koo, B. and Fischer, M., (2000) Feasibility Study of 4D CAD in Commercial Construction. J. Construction Engineering and Management, Volume 126, Issue 4, pp. 251-260 (July/August 2000)

O. Seppänen, R. Kenley Performance Measurements Using Location-based Status Data Proceedings IGLC-13, July 2005, Sydney, Australia

Korman, R., with Illia, Y. (December 2006) Big Design-Build Road Jobs Aren t Foolproof Profit-makers , Engineering News Review (ENR)

Navon, R., and Shpatnitsky, Y. (2005). Field Experiments in Automated Monitoring of Road Construction. J. Constr. Engrg. Manag., ASCE, 131(4), 487-493. 22

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