1、4/23/20221Danny L. Kahler, P.E.Session T314:00 p.m. 5:00 p.m.August 29th, 2006ASQ Annual ConferenceEnergy & Environmental DivisionDesign & Construction DivisionTucson, Arizona4/23/20222lDanny L. Kahler, P.E.lCivil EngineerlBridgefarmer & Associates, Dallas, TXl20+ years of engineering ex

2、periencelASQ Senior MemberlASQ CQA, CQM, CQE and CSQE4/23/20223lModel - A simplified representation of a system at some particular point in time or space intended to promote understanding of the real systemlSystem A system exists and operates in time and spacel(Definitions obtained from Society for

3、Modeling and Simulation International)4/23/20224lModel Centric Design All significant design processes extract information from and update changes to a digital model that represents the real system4/23/20225lThe “model” is represented by lines and numbers on rectangular sheets Each sheet only shows

4、small section of the design Visualizing the proposed design requires significant practical experience Changes to the design are difficult Large labor forces are required for drafting4/23/20226lComputer software that allows a design to be drawn using real world units in the same coordinate system tha

5、t will be used for constructionlComputer networks that allow multiple users to to see the latest version of any design component in its actual location4/23/20227lSoftware packages are just tools that help us work with the datalWe use software to retrieve the data, analyze it, manipulate it, put it b

6、ack in, and present it lModel-centric design is about improving the way we use the data to make design decisions4/23/20228lDesign firms continue to invest in the latest software with little improvement in real productivitylManagers eventually turn deaf ears to production staff requests for each new

7、“killer” applicationlSenior designers still rely on plan sheets to make design changes4/23/20229lFirms can separate pure design from construction document draftinglManagers can make choices about hardware and software investments based on actual productivity needslSenior designers can base their dec

8、isions on the actual design, not limited sheet views of it4/23/202210lPlans OnlylPlans Visualization Plans ModellRoundtrip Engineering Plans ModellModel-Centric Plans ModellModel Onlyl“Whats a model?”lThe plans build the modellPlans and model coexistlThe model builds the planslPure design (no more p

9、lan sheets)4/23/202211lAgencies will continue to require traditional plans for many years to comelWith the Model-Centric approach, the sheets just become views of the modellEach printing of the sheets reflects the most current version of the design model4/23/202212lDesign Among Multiple AgencieslTig

10、hter Project ScheduleslDesign/Build Project TeamslIncreased Cost of ErrorslIncreased Cost of DisputeslIncreased Cost of PersonnellFewer “Seasoned” Engineers4/23/202213lBetter use of technical stafflLess impact from design changeslImproved visualization of the projectlImproved communication with clie

11、nts and contractorslNew methods of discovering and eliminating design & construction conflictslNew design practices to match improvements in construction & survey technology4/23/202214lAllows shorter design scheduleslMore production with less stafflDesigners doing design not draftinglPortabi

12、lity of design to other platformslClients have more influence during designlFaster response to client changeslReduced potential for errorslReduces drudgery of plans productionlBetter communication with construction4/23/202215lPeople trained to communicate in the “l(fā)anguage” of design models and real-

13、time design changes lDevelopment of guidelines to help predict revised production rates and labor costslEstablishment of new skills in how to control and assure the quality of the modellWe need Model-Centric Quality Assurance4/23/202216lModel-Centric Quality Assurance occurs when the evaluation of a

14、dequacy of a design is based on the integrated review of the actual design model rather than a fragmented inspection of individual views (plans)4/23/202217lDocument BasedlMultiple Iterations of Construction PlanslHeavy Focus on AppearancelFrustrating Amount of “Drafting” CommentslReviewer Reward bas

15、ed on Volume of Comments Generated4/23/202218lRequires standards for model definition - these standards may already be hidden in agency CADD standardslNeeds standardized or compatible software that faithfully represents the proposed design model to the reviewer4/23/202219Problems with storm sewer pr

16、ofiles found early in the design process4/23/202220lIf the reviewer and designer are on the same software platform, an experienced reviewer can often provide feedback of what process error or errors probably caused the design flawlQA can evolve from basic third-party product inspection to a team mem

17、ber that provides a value-added analysis of needed design process improvements4/23/202221lFit The static 3-D Integration of the ProjectlFlow Things the project must transport: storm drainage, sewage, vehicles, etc.lFunction Ability of subsystems to do their jobs: signals, gates, message boards, road

18、way signs, etc.4/23/202222lBy borrowing Software Quality Concepts: Validation Verification Accreditation*Terms obtained from DOD sources4/23/202223lValidation: The process of determining the degree to which a model is an accurate representation of the real-world from the perspective of the intended

19、use of the modellDoes the model show us how the components of a proposed design will actually fit together?4/23/202224lVerification: The process of determining that a model implementation accurately represents the developers conceptual description and specificationslDoes the model represent a design

20、 that will meet the performance requirements if constructed?4/23/202225lAccreditation: This is the official certification that a model is acceptable for use within the context of a specific objectivelIs the model sufficiently detailed to produce accurate construction documents ready for bid?4/23/202

21、226lSome contractors already request source design files, and often report the files have fewer errors than the signed and sealed paper plan sheetslAgencies can establish design contract requirements for designer-validated models adequate for bidding purposes4/23/202227lMachine control from the modellInspection without stakeoutlReal-time status of construction progresslTrue “As-Built”4/23/202228lFewer review documentslFaster turnaroundlMore efficient use of manhourslDecreased communication errorslDecreased project risklEarl