• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.122-123
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• 2018

Recently, CM at Risk delivery system(CM@R) that could solve the problems of Design Bid Build delivery(DBB) system has been emerging. In the CM@R delivery system, the contractor negotiates for a maximum guaranteed price(GMP) with the client at the design stage, and the contractor carries out the construction within the GMP. In CM @ R, the construction company with expertise in construction participates from the design stage to reflects the construction know-how in the design. On the other hand, the modification design frequently occurs due to the change of the construction cost when negotiating the GMP. In addition, uncertainties are inherent in the GMP calculation because the calculation is based on unfinished drawings and documents. This study proposes a probabilistic GMP estimation method applying MCS to the BIM - based cost prediction model, in order to extract the accurate quantity information when estimating the GMP and to cope with the change of the construction cost inherent in uncertainty.

• Korea Real Estate Review
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• v.28 no.4
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• pp.53-62
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• 2018

When the contractor does not receive payment for his work due to the client's funding default, he can take various legal measures against the client, in addition to refusing to transfer the building under construction to the client. To claim top payment priority and to demand the equal enforcement of the law by applying for compulsory auction or auction by exercising the right of lien, the contractor should know the construction phase or the point in time when he could exercise a lien or apply for a forced auction of the unregistered building. This study was conducted to examine qualification for lien and auction of an unregistered building. First, the general criteria for qualification for lien from qualification for ownership were examined. This means that an unregistered building can be subject to lien from a certain point in time in the construction phase, where the ownership is qualified as an independent real estate with minimal pillars, roofs, and walls. Second, the contents of the narrow and broad auction qualification were analyzed. As the contractor can select the appropriate legal means to reimburse the construction cost for the unregistered building, the results of this study are expected to provide the bases for qualification for lien on and auction of unregistered buildings.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.295-303
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• 2018

In the DBB delivery system, the design stage and the construction stage are separated. Because of this, design changes frequently occur, and problems such as construction cost overrun, schedule delay, and quality deterioration happen as well. Recently, in the construction industry CM at Risk(CM@R) delivery system, which can systematically solve the above-mentioned problems of DBB delivery system, meet various demands of clients, and overcome the limited cost and period. In the CM@R delivery system, the contractor negotiates for a maximum guaranteed price(GMP) with the client at the design stage, and the CM performer carries out the construction within the GMP. However, uncertainties are inherent in the GMP calculation because the calculation is based on unfinished drawings and documents. In this study, a Probabilistic Earlier GMP Calculation Method by combining a probabilistic tool of Monte Carlo simulation with a case based reasoning is proposed so that the uncertainty in GMP calculation is reflected. After the earlier GMP is calculated, a process to calculate the $2^{nd}$ GMP at the time of around 80 % of detailed deign and to negotiate with the client to fix the final GMP is proposed. The Probabilistic Earlier GMP Calculation Method is verified through the case study. In this study, researchers set the range of GMP through the proposed probabilistic GMP calculation and tried to reduce the risk through negotiation between the client and the CM performer. The proposed method and process would contribute to the successful introduction of CM@R in Korea.