G Dori, M Wild, A Borrmann, O Fischer
A System Model for Lifecycle Monitoring of Bridges
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Laptali E, Bouchlaghem N, Wild S,
A computer model for time and cost optimisation during pretenderstage
Abstract: An integrated computer model for the evaluation of different project duration/costsolutions during pre-tender and pre-contract stages has been developed for multi-storeyreinforced concrete office buildings. The model performs two processes; simulation andoptimisation. The optimisation part, which is the subject of this paper, uses data provided bythe simulation part to determine sets of time vs. cost solutions. The model takes account ofthe precedence relationships, the lag values, and the normal and crash values of time and costfor activities. Linear programming is used to solve the optimisation problem. Minimumincrease in the project direct cost when the project duration is accelerated is achieved by theminimisation of the objective function. The model has been validated by checking theoptimisation process and the validity of the theoretical basis using a hypothetical six storeyreinforced concrete office building. In addition the model has been reviewed by constructionpractitioners using the same hypothetical building to check the validity of the results.
Keywords: Computer modelling, optimisation, time/cost curves, linear programming,Simplex Algorithm
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