is the concrete which has been prepared for casting , cast and cured in a location is not the final destination . the distance travelled from the casting site may only be a few meters , where on- site precasting methods are used to avoid expensive or maybe hun- dered kilometers , in the case of high value added products , where manufacturing and transportation costs are low.
BIM technology and Background
BIM is commonly defined as the process of creating an intelligent and computable three-dimension- al (3D) data set and sharing the data among the various types of professionals within the design and construction team. With BIM technology, an accurate virtual model of a building is constructed with precise geometry and relevant data needed to support the procurement, fabrication, on-site installation activities
BIM into prefab concrete
Design and drafting plays a major role in the cost-effectiveness, timeliness, and quality of the entire process Advantages in terms of reducing redundant de- sign activities, providing an infinite number of solutions, eliminating assumption and design errors, and shortening the time needed for any modification can be obtained from the design and drafting modelling process.
Understanding the process
The prefabricated constructionmanufacturing process consists of three main stages:
Production line in the factory
The production line is divided into Three phases :
Vertical elements , i.e. col- umns and Walls
Horizontal elements ,i.e. Slabs and beams
Coordinated drawings , electri- cal, mechanical , plumbing and any Arch. feauters that re- quired inside the panel during fabrication.
whereby each phase in the production line has a different number of stations. Specific sets of shop drawings are required foreach phase. This stage finishes when a unit is manufacture , later when the elements strength issufficient for transportation , itstransported to site location andready for erection , once erectedother disciplines move in to connect the services in the panelsfor the building to perform as designed.
The amount of the shop drawingsas prescribed in understanding the process section is very huge com- pared to any type of construction , as for instance the follows :Clashing between two ele- ments that size incorrectly drafted , that requires repair before erection.Inaccurate location of the MEP or the Arch feauters , where further repair required to con- nect the services.Using BIM from design to con- struction helps the Teams to over- come the drawings control issues, its always the question , what drawings sent to production when and how to keep the production informed that changes if any in a timely manner.
“Planning & Analysis of the prefabricated concrete buildings using BIM”
During developement stage usingBIM helps visuilazing the location where joints are selected to break- down the structure into smaller elments that can be transported to site , where transportation regualation and the availble trucks are the main factor for how big or small panels can be fabritcated provided the factory capacity and the cranes at site as well , how- ever once the joint are selected , its reflected immediatly into Arch model , where the Architect is to approve or update the building elevation according to selected joint locations , return the notes to Strutcural engineer if any unacceptable joint in which the structural Engineer has to recap with this.
as explained this process can be as difficult as it looks but using BIM keep everyone in the design team informed the changes automat- ically , where the errors is elim- nated since its one channel forthe information to proceed into drawings once the joints are selected and approved , most BIM software has two way link with the famous commercial analysis software , simply the structure Engineer exports the model to be ready for analysis in a click , provided that BIM software recieves all the load- ing information as well as assigned makes the analysis very simple and easy step to go
On compilation of the analysis and if any member sizes are changed, the structural Engineer return the model to the BIM software , where the member sizes will be automatically updated and the rest of the team will be informed the change.
As described analysis procedure goes for all other type of building but the difference in precast con- crete is the definication of each and every pier wall for instance are different from any other type of contruction allowing marking ofpiers automatically that saves time for the Engineer during design of the structure.
BIM is not used only for analysis and drafting , a prefab supplier issues a ticket on each panel , when scanned it keep the design department aware that the element is moved to erection , where if any additional work required on the element , design departmenet easily observe the element situi- tation Not only that, using BIM software helps the planning where they know if the panel is issued for pro- duction and the production team marks the panel when produced , so all teams are informed about the processes , on a click you can recall an element history Controlling the changes during design and coordination through production is challanging pro- cess , however most of Engineers realised the time saving when an element dimensions is changed during further coordiantion when the panel dimensions is changed or any features changed , having the shop drawings automatically updated was a challange to control without using BIM into the process before any updates to be made on the panel , the design team easily can check the panel production status through the software used inhouse , means that they can change their design to adapt the construction process and saving time to gather the information from other departments is elimi- nated.
Having the building elements in the production and released for erection doesn’t mean that design team is done with their job , they continue coordinating the erec- tion itself , during erection the site team keeps asking question and sometimes they change the erection sequence due to the site situiation itself , where it may need to recap the flow of produc- tion from the building one end to the other end , furthermore parts of the building are sometimes made of cast at site concrete that requires a further coordination during site work , all site team uses the models to understand , visuiliaze and request information from the design team.