The application of BIM and IPD in public design and construction

Building Information Modeling (BIM), as the newest entrant to the firmament in construction industry, consists of a technological tool. It can hold large amounts of data--spatial, schedule and cost, accounting, procurement. It also permits users to explore various building designs at the earliest possible stage as well as the relationships among design, constructability, schedule and budget. BIM provides a common language and platform for the project delivery system, especially Integrated Project Delivery (IPD), to communicate, collaborate and coordinate among the multiple project stakeholders. BIM and IPD are widely used in private sector projects, while public owners, such as New York City, face several constraints including a series of procurement requirements imposed by Federal, State and Local legislative statutes. This research outlines the existing constraints and develops an Integrated Design-Bid-Build (IDBB) project delivery model that will provide an opportunity for public entities to adopt many BIM functions and IPD principles into their design and construction process. The framework is developed for New York City public works, which is often required to award construction contracts by lowest price, responsive and responsible bid criteria. The advantages and disadvantages of implementation of IDBB are summarized in this research. Since public works projects, such as in the Department of Design and Construction (DDC) are constrained by procurement legislature and cannot fully apply BIM functions and IPD principles, the proposed IDBB provides a platform to employ many benefits of BIM and IPD. This research used change orders as the project measurement variable. Change orders were organized by categories which were then used to map BIM functions and IPD principles to evaluate possible change order reduction by implementing IDBB. The IDBB model can be quantified by using a developed evaluation tool. Then a change order forecasting model was developed using Bayesian statistics, which help to create the cause and effect relationship between BIM functions and IPD principles with change orders categories. BIM functions and IPD principles will help to reduce parts of the change orders in DDC projects. But there are still some remaining change orders that need to be addressed. Therefore, a contingency calculation model is also proposed in this environment to prevent a cost overrun. By using the cost benefits analysis model, a case study was conducted on a controlled experiment project called System Mechanical Engineering Facility III (SMEFIII). IDBB was performed within DDC regulations and restraints. The findings indicate that IDBB can help New York City DDC greatly reduce design errors, design omissions and field condition types of change orders. Better implementation of IDBB can also mitigate risks of project cost overrun. Recommendations from the case study analysis include encouraging strong leadership on the part of the owner and the compensation structure needs to be carefully designed to both buffer cost overruns and serve as a profit incentive. IDBB, as an alternative project delivery method, allows public agencies to enjoy the benefits of BIM and IPD to the fullest extent possible.