To make it possible to exchange information between dif- ferent BIM models, according to Sacks et al. [6], there are three types of formats for data exchanges between BIM applications: (1) direct link; (2) proprietary exchange format;
(3) public product data model exchange formats. The third type comprises an open standard of information exchange models. It has properties of objects, measures, parameters, materials in addition to geometric properties. They are environments suitable for use in construction analysis and management applications, for example, IFC. This paper investigates the applicability and standardization of the third type of data exchange through the IFC scheme in airport designs.
Fig. 2 BIM model validation process map
According to buildingSMART, the IFC is a standardized digital description of the built environment. It is an open international standard (ISO 16739–1: 2018 [7]), designed to be neutral or vendor-independent and used in a wide range of hardware devices, software platforms and interfaces for many different use cases. Eastman et al. [8] define the IFC scheme as a standardized data model that encodes logically the identity and the semantics (name, identifier, type of object, etc.); the characteristics or attributes (material, color, properties, etc.); relationships (locations, connections, etc.);
objects (columns, slabs, beams, etc.); abstract concepts (performance, cost, etc.); processes (facilities); operations and people (companies, designers, contractors, suppliers, etc.).
The IFC scheme is composed of several organized enti- ties, as shown previously, and based on three structural points, IfcObjectDefinition which defines the entities (ob- jects), IfcRelationship which defines the relationships between entities and the IfcPropertyDefinition which defines the properties associated with the entities (Fig.3).
According to Nawari [3], the IFC is proposed to be a high-level data model that is intended to be independent of any software implementations, which is to stay, must be strictly neutral. It offers a consistent data structure for storing construction information, but does not impose, or even allow, any particular method of implementing it in a soft- ware application. Currently, the Industry Foundation Classes (IFC) scheme is used to exchange information from one party to another for a specific business transaction.
Due to the wealth of information that can be encapsulated in attributes, properties and geometries throughout the life cycle of a building and its environment, the amount of IFC data is very large. To avoid the difficulty of transferring information in an IFC model, it is important to define uni- form means and content specification standards to be used in stages of the building's life cycle. Thus, it is important to establish what information should be delivered, by whom, when and to which recipient [9].
To solve this, buildingSMART developed the structures of the Information Delivery Manual/Model View Definition
[10]. The idea is to reduce the space for interpretation and facilitate the implementation of use cases in specific appli- cation areas. The Information Delivery Manual (IDM) is a method used to consistently describe BIM processes (IDM, ISO 29481). The predefined IDM structure and uniform methods for presenting process models allow users to accurately develop, agree and document their BIM pro- cesses. From the data defined in the IDM, a Model View Definition (MVD) defines the specific sub-elements of the general IFC data model that can support the specific data exchange requirements [11]. That is, an MVD is a recom- mendation for what data and elements the IFC model should include, depending on the purpose of the model exchange.
As an example of MVD, we can mention: Coordination View 2.0, FM Handover View, Structural Analysis View, among others.
In general, data exchanges used in rule verification sys- tems must meet certain requirements. For this work, essen- tial requirements are considered: (1) use of appropriate BIM tools for modeling objects. For example, the creation of a
“wall”must be done using the“wall”tool of the modeling software; (2) guarantee that all nomenclatures are corre- sponding to those established in the manuals. For example, for the names of the environments, use the names established in the INFRAERO manuals (boarding lounge, check-in queue, etc.); and (3) ensure that the IFC mapping and its native BIM creation tools are correctly configured to export the IFC model that complies with the MVD defined by the rules verification systems to be used for airport projects. In this case, Coordination View 2.0 will be used.
6 Results
The initial studies of this research, presented in this paper, point to the importance of standardizing the BIM informa- tion models of airport designs. In order to arrive at these initial results, simulations were carried out on a passenger terminal design modeled on BIM authoring software. These simulations show, even in a preliminary way, the feasibility
Fig. 3 Simplified example part of the IFC hierarchy classes
of standardizing certain airport design parameters to check compliance with requirements (Stage 03—Fig.2). These studies also indicate the need for without creating protocols for modeling so that the information is hung following a standard coding in line with the rules created for evaluation (Stage 02—Fig. 2).
The starting point of the research was to analyze the evaluation process developed by teams of airport design analysts in Brazil. The results indicate that it was possible to identify some important points regarding the project evalu- ation process currently in force (analog): (1) the quality of the analysis is directly associated with the analyst’s maturity, (2) ambiguity in the process of analyzing airport designs, having in view of the lack of standardization of analysis, with each analyst responsible for a specific criterion, (3) extended analysis time considering that the majority of Brazilian airport designs are still submitted for analysis in two-dimensional computer-aided drawings (CAD).
On the other hand, the first studies have shown that through the use of checking through regulatory codes and the standardization of the information model in BIM soft- ware (using the IFC format), it is possible to identify the possibility of improving the current process of airport designs. But, for this, there is a need to develop the manual for standardizing guidelines for modeling designs in BIM software. Through the application of the rules established in the manuals, which may be incorporated in the templates of the designs teams, the building information models produced by the designers may be able to check the automatic rules carried out by the analysts of the competent bodies respon- sible for such activities (Stage 03—Fig.2).
The research current stage consists of checking automatic evaluation rules and identifying the minimum IFC properties to be hung in the BIM model. Two evaluation situations were simulated in existing components in the Airport Plan- ning Criteria and Conditions Manual (INFRAERO, 2006).
Each simulated rule was classified according to the general classes of rules recommended by Solihin and Eastman [12], being: class 01—rules that require a single or a small number of explicit data; class 02—rules that require simple derived attribute values; class 03—rules that require exten- ded data structure; and class 04—rules that require a“proof of solution.” The following will show examples, already implemented (see Figs.4 and 5), which demonstrate the description of the rule checking, the classification of the rule and the minimum properties required in the design's BIM IFC model.
Table2describes the simulation rule 01 presented in this work. The condition of acceptance of this rule is a minimum distance of 10.00 m between the limits of the aircraft envelopes in the apron. If the IFC model is compliant with, the analysis software (SMC) will show the graphical result in green (compliant with); otherwise, the graphical result in the
verified component is not compliant with, SMC will show the graphical result in red (not compliant with), for rule 01, the condition was compliant, so the SMC identified com- pliance with the established rule, without the need to change the design.
Table3 describes the simulation of rule 02 presented in this work. The condition of acceptance of this rule is: the width of the checking service desk must be 3.00 m. If the IFC model is compliant, the analysis software (SMC) will show the graphical result in green (compliant);
otherwise, the graphical result in the verified component is not compliant with, SMC will show the graphical result in red (not compliant), for rule 02, the condition was notfit, so the SMC identified the non-compliance with the established rule, with the need to resend the airport design model to the team of designers responsible for the design review.
What can be seen with these two examples is that just as it is important to establish rules for the evaluation of infor- mation models of buildings, the creation of rules alone is insufficient for the evaluation process to be efficient. For the rules to be effectively read and validated or not (true or false), the information models of the designs must be orga- nized in such a way that the information present in the IFC properties is standardized in the creation of the models according to the parameters established in the rules checking the model. Also, it must be exported in IFC using the pro- tocols set out in the manuals (for example, using the appropriate MVD). In the rule presented in Fig.5, for example, entities such as IfcSpace, IfcQuantities, and Boundign Box Widht were considered. For the information model to be used to evaluate the rule transcribed in Table3, the information model would need to contain these entities.
IfcSpace, for example, would need to be defined as“service desk.”Any other word defining this space would result in the impossibility of evaluating this rule.
These two examples described in this paper demonstrate, even preliminarily, the importance of standardizing IFC entities within the BIM information models during the design process. That is, in order for the evaluation team to be able to successfully carry out the automated rule checking process using BIM analysis software, the BIM model must contain the standardized IFC entities, incorporated into the BIM model. These entities must be correctly incorporated in the design process, according to the parameters created in the rules template implemented in the analysis software. For this, it is necessary to know the organization structure of the information present in the analysis software, so that it is possible to overlap the IFC data with the set of rules created.
It is also necessary that the BIM information models, developed by the designers, have incorporated the IFC entities that are following the rules established in the mod- eling software, as well as their terminologies (for example,
“service desk”).
It is important to note that the examples of the rules presented in this research refer to class 02 rules [12], that is, they are rules that require attribute values derived from simple; this does not mean that this method cannot benefit analysts in the validation of rules classes 03 and 04.
A classic example of the use of these last rules is the
so-called design assessment tool (DAT). This tool, devel- oped by the Georgia Institute of Technology, used the cir- culation and safety rules found in the US Courts Design Guide [13] encoding them in 302 computable parametric rules [5]. Another example of a class 04 rule, for the case of PT, would be for the analyst to assess how an airport worker Fig. 4 A view representing the compliance with rule 01, automatically evaluated in SMC
Fig. 5 View representing the non-compliance with rule 02, automatically evaluated in SMC
would make an access path through the service area to a certain system within the PT with his equipment to perform maintenance or repair in a specific system. In this case, it would be necessary for the analyst to have knowledge regarding the building maintenance processes, as well as, to have knowledge of lessons learned from other projects; thus, this type of analysis could be semi-automated.
From the moment it is possible to automate the analysis process in a set of rules, be they simple or more complex, consequently this automation will allow more time for analysts to deal with more pertinent issues regarding effi- ciency and the design process, such as form analysis, func- tionalities related to operational activities, building maintenance, and operation processes, among other relevant points. In the current evaluation process (manual), analysts spend a lot of time in the evaluation phase, checking a series of components that have the potential to be implemented in a code checking process. An example of possible components to be implemented in an automatic verification process are the items of architectural design for an Airport Passenger Terminal [2]. In this case, mentioned above, the authors identified 119 components grouped into 06 categories [14].
Figure6demonstrates the time and energy ratio that the analyst currently has to verify compliance with the rules. In Table 2 Rule description 01 verified on BIM model
Reference document: manual of criteria and conditioning of airport planning—INFRAERO (2006)
Rule description: minimum distance between an aircraft envelope area in the apron
Condition: the distance between wingtips 10,00 m
Classification of the rule—according to Solihin and Eastman [12]:
Class 02
Verified IFC properties | Verified SMC (ruleset)
IFC entity: IfcSpace/IfcProperties: Name = ENVELOPE|SMC Parameter: Tolerance = 10,00 m
Table 3 Rule description 02 verified on BIM model
Reference document: manual of criteria and conditioning of airport planning—INFRAERO (2006)
Rule description: minimum width of the check-in desk Condition: minimum width 3.00 m
Classification of the rule—according to SOLIHIN, EASTMAN [12]:
Class 02
Verified IFC properties | Verified SMC (ruleset)
IFC Entity: IfcQuantities/Boundign box width/constain: 3.00 m
Fig. 6 Relationship between project analyst activities
scenario 01, the analyst performs a manual analysis process, devoting more time to check the low complexity rules, leaving more time to analyze the more complex rules. On the other hand, in scenario 02, with the aid of a computational system, the analyst optimizes his time in the analysis of the simplest rules (and that takes less time for implementation) and starts to have more time to analyze more complex rules in a process manual and automated hybrid. This does not mean that complex rules cannot be implemented, but that the implementation of simple rules (classes 1 and 2), at an early stage of transforming design evaluation practices, is easier to implement and at the same time can bring great productivity gain to the project evaluation activity.
7 Conclusion
This research, even though it is still in the development phase, demonstrates the importance of creating a standard- ization process in the modeling of information during the development of airport designs in software authored by BIM, considering the export to an integrated IFC model. In view of the inexistence of manuals dealing with this subject in Brazil, it is possible to observe the potential that this approach has and may, shortly, benefit all teams of airport designs and analysts.
Once the BIM Information Modeling Guidelines Manual (standardization of the BIM model) based on the technical standards for this type of design has been created, it will benefit the professionals involved in the designs’ synthesis and evaluation process at various points. Thus, the teams working on the design development (synthesis) will have a reference document for standardizing IFC information to be used during the BIM design process, which can avoid sub- mitting designs with incomplete or inconsistent information.
Likewise, analysts will be able, through rule checking, to automate much of the process that is currently predomi- nantly manual, taking advantage of time savings, increasing efficiency in the evaluation process, minimizing ambiguity, standardizing the evaluation process, among other benefits related to the design approval phase. In addition to the possibility of later use of the IFC model for maintenance and operation of the airport.
Another potential observed was the possibility of using the parameters of the analysis software for other types of evaluation of airport designs, other than those addressed in this research. There are elements of design evaluation, such as noise zoning analysis, protection zone analysis, lateral transition ramp analysis, approach ramp, among others,
which can also be customized in rules, or new ones can be created rules for analyzing these parameters that in many cases go beyond the airport site boundary.
References
1. Benning, P., Dumolin, C., Dehlin, S., Tulke, J.Âberg, P., & Ryd, N. (2010). Collaboration Processes: A State of the Art.
2. Guedes,Í., & Andrade, M. (2019). Automatic rule-based checking for the approval of building architectural designs of airport passenger terminals based on BIM. InProceedings of the 37th eCAADe and 23rd SIGraDi Conference (Vol. 2, pp. 333–338).
Porto, Portugal: University of Porto (11–13).
3. Nawari, O. N. (2018).Building information modeling: Automated code checking and compliance processes, 1st edn. Boca Raton; CRC Press.
4. BIM ThinkSpace. (2015). Episode 24: Understanding Model Uses, v 0.73.
5. Eastman, C., Lee, J., Jeong, Y., & Lee, J. (2009). Automatic rule-based checking of building designs.Automation in Construc- tion, 18(8), 1011–1033.
6. Sacks, R., Eastman, C., Lee, G., & Teicholz, P. (2018). BIM handbook: A guide to building information modeling for owners, managers, designers, engineers, and contractors(3rd ed.). New Jersey: Wiley.
7. ISO—International organization for standardization. ISO 16739-1:
2018—Industry Foundation Classes (IFC) for data sharing in the construction and facility management industries.
8. Eastman, C., Telcholz, P., Sacks, R., & Liston, K. (2008).BIM Handbook—A guide to building information modeling for owners, managers, designers, engineers, and contractors. New Jersey:
Wiley.
9. Borrmann, A., Beetz, J., Koch, C., Liebich, T., & Munic, S.
(2018). Industry foundation classes: A standardized data model for the vendor-neutral exchange of digital building models. In A.
Borrmann, M. Köning, C. Koch, & J. Beetz (Eds.), Building information modeling: Technology foundations and industry practice(1st ed., pp. 81–126). Cham: Springer.
10. BuildingSMART. (2113). Construction operations building infor- mation exchange, MVD definition for IFC4.
11. Steinmann, R. (2018). IFC certification of BIM software. In A.
Borrmann, M. Köning, C. Koch, & J. Beetz (Eds.), Building information modelling: Technology foundations and industry practice(1st ed., pp. 139–154). Cham: Springer.
12. Solihim, W., & Eastman, C. (2015). Classification of rules for automated BIM rule checking development. Automation in Construction, 53,69–82.
13. Judicial Conference of the US, US Courts Design Guide, Washington DC (2007).
14. Superintendência de Empreendimentos de Engenharia (2006).
DEEP Gerência de Planejamento de Engenharia—EPPL. Manual de Critérios e Condicionantes de Planejamento Aeroportuário.
Infraero.
15. March, S. T., & Smith, G. F. (1995). Design and natural science research in information technology.Decision Suport Systems, 15, 251–266.
16. International Air Transportation Association (IATA). (2019).
Airport development reference manual,11th edn.
17. Garber, R. (2009). Closing the gap information models in contemporary design practice(Architectural Design March April 2009 Vol. 79 No. 2). Wiley.
18. Eastman, C., Telcholz, P., Sacks, R., & Liston, K. (2014).Manual de BIM—Um Guia de Modelagem da Informação da Construção para Arquitetos, Engenheiro, Gerentes. Porto Alegre: Construtores e Incorporadores. edn. Bookman Editora Ltda.
Ítalo Guedesis an architect and urban planner, specialist in BIM Platform, Master in Architecture and Urbanism at the Federal University of Per- nambuco. He has professional experience in the development of BIM pro- jects in infrastructure and architecture of airports in Brazil, currently developing a master’s research project on Verificação automática de regras em projetos de aeroportos no Brasil com base em BIM, professionally linked to the Works and Projects Directorate—Secretariat of Infrastructure, City Hall of Ipojuca/PE, researcher and teacher graduate course.