Virtual design and construction (VDC) is a process used to enhance collaboration, reduce time and costs, and foresee project constraints before they occur. The process uses a computer-aided design model, which is often referred to as a building information model (BIM). It is sometimes viewed as building the project twice – once in the computer and once in the field.
VDC takes advantage of these intelligent, feature-rich BIMs created during the design process to pave the way for open channels of communication among all project partners. VDC has helped developers foresee project constraints before they arise, which reduces rework and saves time and money.
Consider the core component of VDC: the creation of a 3D project model using intelligent modeling techniques. It is important to note that this model is not an artist’s rendering of how the project is imagined. Instead, the model is an engineered collaboration of designs from different sources that is scalable, measurable and precise.
Additionally, schedule and cost are added to the model to create a virtual execution of the construction project that is readily available throughout the process. The complete package can ultimately be turned over at construction completion for use in facilities management.
VDC for wind farms
VDC is a standard practice in the building-construction industry, but the core techniques of this intelligent model could also be beneficial to other types of construction projects, including wind farms.
During the initial project development phase, VDC is used to communicate project ideas among the owner, construction company and design team. It is a way to visualize all of the project’s constraints and allow for easy changes before the project has begun. Additionally, the model can be used to educate landowners, financiers and public officials about the expectations of the project.
Most wind projects have a civil construction element that can be quite sizable, especially in areas of complicated terrain. During the pre-construction phase, numerous alignment alternatives can be analyzed in order to verify the best location and the most cost-effective access roads for the project. By modeling the roads, slopes and pad areas, the earthwork component of the project can be properly accounted for in the budget and equipment needs.
These models can be used to determine vehicle selections for earthwork, along with the mass haul associated with the area. In addition, the VDC model can be remotely exported to field equipment for machine-controlled grading via GPS, thus reducing time and unnecessary survey work. The GPS model also gives the equipment operator greater control over the accuracy achieved.
Because most wind projects are located in rural areas, roads are not always available to accommodate the size of construction equipment and delivery vehicles that need to make their way to the project site. Being prepared to accommodate this need will significantly reduce project delays and allow for the widening of sharp curves when necessary, the changing of grades during design, or an additional helper vehicle for steep grades.
Existing infrastructure is always a concern both above and below ground. Using GPS-controlled intelligent equipment and proper marking procedures, the model can warn the team about possible utility conflicts and address potential clashes before they occur. Clash-detection methods are always useful for coordinating each discipline’s designs. For example, in a wind turbine foundation where concrete rebar is modeled, electrical conduit clashes can be visually and electronically detected and resolved, eliminating field modifications and schedule delays.
VDC can also have a significant impact on site-logistics planning. Due to the number of large pieces being delivered and the expanse that is required for storage, turbine-component deliveries can be quite complicated. By modeling the different components to include the location in which they are placed at delivery and the order in which they arrive on-site, wind energy developers can ensure the optimal plan is carried out and increase their confidence that deliveries will go smoothly.
By designing each stage of the construction process in a workflow model, total disturbance areas are calculated. Typically, this area can be greatly reduced through accurate planning. What was once an estimation of the acreage that should be cleared for construction is now a precise, environmentally conscious, engineered model that eliminates unnecessary project construction limits. Landowners will embrace this mindful planning.
Skeptics may argue that some renewable energy projects have such tight project timelines that they do not have time for VDC models. However, it is usually in the process of developing these fast-paced projects that many errors, including safety incidents, occur due to lack of pre-planning and the misguided assumption that each project is typical.
Using the VDC model to properly plan each stage of the process can improve the safety, quality and productivity of the wind project. w
Marketplace: Construction & Engineering
Virtual Design: An Idea Whose Time Has Come
By Sera Maloney
Wind developers are beginning to see the significant benefits provided by virtual design and construction.
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