Study on trade-off of time-cost-quality in construction project based on BIM XU Yongge 1, a, Wei Ya 1, b

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1 Internatonal Conference on Economcs, Socal Scence, Arts, Educaton and Management Engneerng (ESSAEME 205) Study on trade-off of tme-cost-qualty n constructon project based on BIM XU Yongge, a, We Ya, b X an Unv.of arch. Tech., X an 70055, Chna; a @63.com, b @qq.com Keywords: Buldng nformaton modelng; Constructon project; Tme-cost-qualty trade-off optmzaton; Genetc algorthm. Abstract. Wth the development of BIM technology, BIM provdes a new drecton for the project management of three objectves. Based on the current stuaton of the project tme cost-optmzed mass balance studes, pontng out the mplementaton mechansm of achevng the trade-off of tme-cost-qualty n constructon project based on BIM manly orented components of the BIM model based; the use of Structured Query Language query statstcs data nformaton needs combned bll of quanttes calculaton method for the specfcaton, prelmnary engneerng scale generaton; establshment of Project relatons system model. In the process duraton s subject, for the constructon of uncertanty factors such as nterest rates and prces, through the establshment of qualty, cost and schedule functon, the establshment of qualty balanced schedule cost optmzaton model, usng genetc algorthm model of the optmal soluton are obtaned. Wth BIM case fnally proves the ratonalty of the model and the effectveness of the proposed genetc.. Introducton Balance between the three objectves of the optmzaton problem has also been a research scholar n the feld of project management focus at home and abroad, as early as 2005 EI-Rays on the proposed project schedule cost optmzaton of the qualty of dscrete model (TCQTP), 2008 Mr Yeung Hung et al. Takng nto account the uncertanty of the project, presented the project duraton cost qualty Fuzzy Tradeoff Optmzaton model (FTCQTP), and the use of adaptve genetc algorthm to obtan the optmal soluton of the model, n 203 camp Lan []and others to step duraton of decson varables to establsh a balance of the three fuzzy optmzaton model, genetc mmune partcle swarm optmzaton algorthm wth fuzzy multle Pareto optmal solutons and draw a three-dmensonal scatter plot. But prevous studes, there are two problems: frst, the qualty of the project cost optmzaton model schedule some parameters by the polcy makers need to gve ther weghts, but often the actual stuaton of the project s very complex, lmted experence of polcy makers, leadng to rght n the weght value s not enough objectve factors affectng the scentfc model[2]; and second, the above model s based on a comprehensve CAD-based optmzaton, the use of related management software to the CAD model and cost, schedule software ntegraton to gve 4D model, then wth manual or sem-manual mode wll cost data, schedule data and CAD models lnkng the lack of nteroperablty n ths way, but also very complcated, to some extent, hnder the smooth progress of the project management [3]. The man goal of the project s to control tme, cost and qualty, and these three mutual unty of oppostes. In the project management process, n order to acheve the project's economc and socal benefts, usually we need to study how to optmze the combnaton of the three, the ratonal allocaton, n order to acheve the qualty requrements of the project goals and schedule targets wthn budget lmts. To acheve a balanced optmzaton of the three means of constructon resources to the project, constructon materals and nstallaton costs dynamc,, and other complex nformaton have a defnte to control. Parametrc BIM technology through the establshment of a multdmensonal model of Partcaton partes to establsh nformaton platform, a collecton of nformaton can be hghly utlzed to acheve vsual effects, optmze the constructon schedule, 205. The authors - Publshed by Atlants Press 864

2 mproved constructon methods, cost savngs, to acheve a balanced schedule optmzaton project cost qualty [4]. 2. The optmzaton mechansm of trade-off of tme-cost-qualty n constructon project based on BIM Buldng Informaton Modelng BIM (Buldng Informaton Modelng, called BIM) s a three-dmensonal dgtal magng technology, the ntegraton of multle modelng tools, a dgtal representaton of the buldng to acheve physcal and functonal characterstcs. Currently BIM technology research and applcaton resource consumpton n the largest constructon phase s not yet mature, n the project management of the above studes most scholars of BIM only ndependent research for the tme, cost and qualty, but as the project management key elements of the project schedule, there s a dalectcal relatonsh between cost and qualty, the three unty of oppostes, and can't focus only on the use of BIM to acheve optmzaton of project management from the actual purpose of the work schedule, cost or qualty s unreasonable. In fact, BIM has the followng three characterstcs can be acheved cost-qualty balance project schedule optmzaton: Frst, based on the components of the BIM model-orented, relatonal database objects for each component n order to "record" n the form generated correspondng table, and can be transferred va structured query language of the data n the table, wth the fnal form by Graphc Converter buldng models reasonable propertes, provde tmely and effectve data base for the BOQ, project cost, schedule and so on. Secondly, the use of Structured Query Language queres requre statstcal data combned wth the constructon bll of quanttes calculaton specfcaton (GB ) to generate prelmnary engneerng scale. For the Bll of Quanttes not automatcally generated can be ncorporated nto sporadc work tems table based prcng norms, the lst of measures project, other projects wthn the lst. 865

3 CAD BIM, Project Scope Constructo n program Project Scope Constructo n program WBS WBS(Engneerng - Quantty - Lst) Logcal relatonsh Logcal relatonsh Progress plan Progress plan &cost &qualty &cost &qualty Schedule optmzaton Schedule optmzaton Target plans Constructon gude Q&A Q&A 2 Q&A n Q&A Q&A 2 Q&A n Buldablty 4D modelmg 4D modelng Constructon process Constructon gude carry out carry out Fg. Comparson of tradtonal and BIM based three target equlbrum optmzaton process 866

4 Fnally, based on the BIM model and relatonal databases, n order to establsh the relatonsh between the project system model as the core. The model project components, project schedule, BOQ tem assocated wth the model by assocatng the three, for engneerng scale each component has unque Structured Query Language query commands, through the query assocated wth the project lst of tems correspondng amount, when the nqury s completed, the components assocated wth the BOQ tems also completed [5]. Through the above analyss, the three major objectves of the tradtonal balancng optmzaton processes and optmzng processes were compared based on three objectves balanced BIM, shown n Fgure. Can be vsualzed by the followng dagram shows the dfference between them [6]. 3.Constructon of equlbrum optmzaton modelng 3. Basc assumpton Hypothess : the project has no other resources except the funds Hypothess 2: each job s composed of a fnte number of jobs and s ndependent of each other, and the duraton of each job s subject to normal dstrbuton. Hypothess 3: the uncertanty n the constructon process of the engneerng project s expressed wth hestaton. Defnton : project cost ncludes drect cost and ndrect cost of two parts. Drect costs nclude labor costs, materal costs, constructon machnery and constructon costs, etc., ndrect costs, ncludng the cost for the project management, etc. Defnton 2: the total qualty of the project for the work s the average value of the qualty of the 3.2 The restrctng relatonsh among the duraton /cost / qualty. The restrctng relatonsh between the duraton and cost Ths paper assumes that the ndrect cost s lnear wth the project duraton. Because of the long term and the tme value of the project, the project cost s n the process of the project. Wth the contnuous compound nterest method to calculate the tme value of money, the functon relatonsh between tme and cost for: r o t j d j P A, 0, T T MnC C P A,, T q e 0 j Among them, C s the fxed value, expressed as a unt of tme wthn the connecton fee. P / A s the present value of the annuty factor. 0 s the dscount rate for the benchmark. q j s the cash flow for the drect cost of work j. t j s the fnsh tme for the pre work. d s the duraton of work j. r s as a j unt of tme prce ncreases, the project started constructon on the average value of a year buldng materals prces. 2. The restrctng relatonsh between the duraton and qualty In the process of engneerng constructon, f the project duraton less than or close to normal perod may lead to shoddy, reducng the qualty of the project. If the project duraton s too long wll appear "student syndrome" effect, leadng to tardness, cost, project qualty declne [7]. Accordng to the above characterstcs, too short and long duraton can reach the optmal project qualty, whch s n lne wth the characterstcs of the bell curve. In ths paper, a bell shaped curve expresson of the functon relaton between the duraton and qualty: n n Q =,2, n : Q 2b Q 2b Tn T n n o Tn To a a Among them,q s the total project's qualty, Q s the qualty of work, To s the shortest tme of,a s the dfference between the mnmum tme and mum tme of.b generally taken to be

5 3. The probablty of completon Ths paper evaluate the probablty of completng the project accordng to the sze of the planned duraton of the use of probablty of completon. PERT network analyss assumed that the duraton of the work of obedence β dstrbuton s approxmated by a thrd estmaton method to estmate the value of three tmes, that s the shortest, longest, and most lkely duraton, ths method s certanly the type of problems nto non-calculated wth defnte problem wth the varance estmated tme devaton analyss, correlaton formula s as follows: To 4Tn T TIP To T Tm T 6 6 Among them, To s the mnmum duraton of work, T n s the normal duraton of. T s the longest duraton of, s the standard devaton duraton of, s the project's probablty of completon, T m represents the sum of the average duraton of the work on the crtcal lne, s the standard devaton of crtcal lne. 4. The equlbrum optmzaton model Takng the project constructon perod as the research object, consderng the qualty and cost of the project, the constructon project cost and the qualty of the project s bult. Z mn C,Q -, - 4.Model solvng Equlbrum optmzaton modelng can be consdered as a combnaton optmzaton problem. Because of the complexty of engneerng projects, the genetc algorthm can quckly fnd the optmal soluton n the whole space, and the genetc algorthm can quckly fnd the optmal soluton n the space. Chromosome structure: each chromosome has a n gene, each gene poston represents a process, each gene value ndcates the operatng tme of the correspondng process. Genetc manulaton:() Selecton operaton roulette wheel selecton method;(2) Bnary mutaton operaton s used n mutaton operaton;(3)two-pont crossover crossover selecton method; adaptve parameters usng the followng formula: Crossover probablty: 2 f favg f f avg f f avg pos CIS f < f avg Varaton probablty: pos mut = Among them,, 2, 3., 4 0, ;f stands for the genetc manulaton of two ndvduals to adapt to a larger value; f avg stands for average ftness value; f stands for the mum ftness value. (4) The adaptve value takes the comprehensve evaluaton ndex R, the evoluton along the adaptaton value n the drecton of large. d S A, SA R A d S A, S A d S A, S A d S A, SA w dsx, S ds A, SA w dsx, S x x xmn f f f avg f avg f f < f avg f avg x x x 868

6 A stands for postve deal soluton, -Qmn - Pmn ;The weght of a s x C,-, P, mn Q - A stands for negatve deal soluton C, w, whch s assgned by the decson maker. (5)The calculaton s termnated when the best ndvdual for 30 generatons dd not change. 5. Case Study BIM 4D constructon smulaton technology n the person A comprehensve hosptal for a practcal applcaton. The total constructon area of square meters, of whch the ground area: 2793 square meters, underground area of 576 square meters. Buldng storey heght: 3 on the ground floor, 3 storey heght of parapets meters, meters the hghest pont, 5 m three storey underground; the frst floor layer s 4.8 meters tall, two to fve storey s 4.5 meters, sx to 3 layers of 3.6 meters hgh. The key of BIM technology applcaton s to use structure Revt to buld 3D model, based on BIM model for component orented, usng structured query language to extract the amount of engneerng materals and the amount of statstcs from the model. The establshment of the project schedule wth the Project Mcrosoft after the establshment of 3D vsualzaton model. Select one of the sub tems of the work duraton, qualty parameters and the drect cost s shown n Table : Table sub-project duraton, qualty parameters and drect costs Reference Table Subproject T n Normal tme Shortest tme Longest tme T C C n Q n T o Order C =300, 0 =8%, =5%, The scale of populaton s 300. =0.9, 2 =0.3, 3. =0.5, 4 =0.2. Obtan: T mn =58, T =23, Q mn =0.835, Q =, C mn =7500, C =8500, Solvng the 40 generaton termnaton, the satsfactory soluton s C=82400, Q=0.873, T=73, Schedule as shown n Fgure 4: C o Q o Q Concluson Fg.4 schedule network dagram In ths paper, the realzaton mechansm of BIM n engneerng mult dmenson management s cut n pont, and the three aspects of qualty objectves, tme targets and cost objectves are consdered. Through the ntegraton of BIM management system, t makes up for the defects of the exstng engneerng project management system, whch greatly mproves the constructon management decson-makng, and provdes a new way for the applcaton of BIM technology n engneerng project management and decson makng. However, the practcal applcaton of the model has to be used to test, and the factors affectng the qualty of the project constructon perod are dfferent from the actual characterstcs, whch wll be further deepened n the follow-up study. 869

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