using multi criteria analyses and bim to evaluate design...

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Using Multi Criteria Analyses and BIM to evaluate design solutions of complex buildings A case study in automated KPI checking in the early desing phase

L.A.H.M. van Berlo1, E. Bektas1 and H.J.L.M. Vullings1 1Netherlands organisation for applied scientific research TNO Delft, The Netherlands [email protected]

Key words: Building Information Modelling, multi criteria analysis, decision support, data management, code compliance, automation, model checking

Abstract: The overall objective of the EU supported ELASSTIC project is to improve security, safety and resilience of large scale multifunctional building complexes against natural and man-made disasters. This improvement is done by providing a methodology and tools which evaluate criteria of security, safety, as well as other criteria, and apply them to early design concepts and therefore planning phase of such projects. The development of a decision support tool based on Multi Criteria Analysis was created to facilitate this. Using this tool, designers and stakeholders can see immediate impact and trade-offs in design changes on the performance of the building. This paper is an explanation to the use of MCA tool and what the possibilities are regarding MCA.

2 DDSS 2016 1. INTRODUCTION

1.1 The Elasstic concept

In recent years the use of Building Information Modelling (BIM) has increased in the Architectural and Urban domain.

In the EU supported research project ELASSTIC the BIM concept was used during the early design phase of a complex building. The overall objective of the ELASSTIC project is to improve the safety, security and resilience of large scale multifunctional building complexes to natural and man-made disasters by providing a methodology and tools which enable to include security and resilience from the early design and planning phase of such projects.

The Elasstic concept consists of four main clusters of technology: - Building Information (BIM) - Simulation models (e.g. for evacuation, energy, etc) - Sensor information - Multi Criteria Analyses (MCA) The Elasstic concept is about the communication between these four

main technology groups. The ‘Multi Criteria Analyses’ (MCA) is providing the end-user the interface to evaluate safety and security of the building design. This paper will focus on the integration between Building Information Models (BIM), Simulation models and Multi Criteria Analyses.

Figure 1. Schematic representation of the ELASSTIC technology

concept.

Using Multi Criteria Analyses and BIM to evaluate design solutions of complex buildings

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The Elasstic project had a strong focus to get simulation results available

early in the design process. In this case the influence on the design is still very high without large consequences.

To reach this goal the simulation models should be able to run in an automated, autonomous way; without human interference.

The combined results of the simulation models are fed into a Multi Criteria Analyses tool. This MCA tool shows results on predefined Key Performance Indicators of the design.

The concept makes it possible to have immediate feedback on the performance of the design without human interpretation or delay.

In the Elasstic project a proof of technology was build and a use case was tested.

This paper describes the technology that was developed and the results of the use-case in the project. The use-case description will elaborate about the different roles that can be evaluated in the MCA tool.

Conclusions indicate that MCA is a valuable technology as a Design and decision support tool in the early design phase of complex buildings, hence the automation of simulations is feasible.

1.2 Example

The concept is best described with an example. Let’s focus on the case of a fire in a building.

In case of a fire in a building, the sensors from the Building Management System (BMS) pick it up. The BMS probably responds with the classic sprinkler system. A notification of the fire is also send to the evacuation simulation. The location of the fire, smoke and maybe intensity are available data at this moment in the process. With advances in building management systems the number of people and their location might also be available as data. The evacuation simulation calculates the most effective evacuation route for the people in the building. To do this, it needs to calculate the spread of the fire so it also triggers the fire simulation. For these simulations information about the building is needed. This data comes from the (static) BIM. In case, parts of the building are destroyed, even this new information is available in BIM and have to be read by the BMS. When the BIM data shows installations with high risk of explosions, the ‘explosion simulation’ can be triggered. The structural integrity of the building might also be evaluated due to the effects of the fire and/or explosions.

The most effective evacuation route, due to the recent state of the building, is send to the building management system. By using signs the

4 DDSS 2016 people in the building can be evacuated via the safest route in the most effective and efficient way. When people don’t use the suggested route, sensors (like cameras) can pick up this deviation and start a new simulation. Resulting in a recalculated optimum evacuation route that is send to the building management system.

Other information from sensors can also influence the process flow. For example when walls break down due to fire; the BIM data set gets updated and this new dataset is used as the base for evacuation simulation. In this case new evacuation routes may come available. Or when parts of the building won’t provide structural safety anymore (found by a combination of sensors in load bearing columns and beams) this part might be prioritized in the evacuation (and the BIM data updated).

To get this theoretical idea into practice, the ELASSTIC project was started. During this project we tried to implement the concept with open source and closed tools, simulation models and open data standards. The research methodology was that of applied research.

This report lists the results of the applied research, gives an overview of the work that is done and states the research findings and conclusions.

1.3 IT architecture

The basic principle of this concept is that the sensors, the BIM data and the simulations are not lined up in a predefined workflow. The interaction between these tools is ‘event driven’.

The principle of ‘even driven’ interaction is not new in IT architecture but never applied in this way on a building. It facilitates the use of small ‘microservices’ that seamlessly connect and integrate. These small services "do one thing and do it well". It is described as follows:

• The services are small - fine-grained to perform a single function. • The organization culture should embrace automation of tasks. • The culture and design principles should embrace failure and faults,

similar to anti-fragile systems. • Each service is elastic, resilient, composable, minimal, and complete.

The concept of micro-services is used in ELASSTIC to connect the different simulation tools to the BIM data. Every simulation tool should be developed as an online service that is minimal and complete. The interface to the tools should be BIM compatible.

This brings a challenge for the individual simulation tools, but is the most durable architecture for long term innovations and business models.

The core innovation of the ELASSTIC BIM concept is the automation of human tasks. By automating operations on BIM data the manual workload is eliminated.


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At this moment the industry is driven by a process that has little

information in the beginning of a project, and high influence on the changes. Later in the process the ability to influence costs is limited. In this stage however, there is much more information.

The ideal is to have valuable information earlier in the process, when there is still the ability to influence the project. BIM is often seen as a technology that could be used to increase the information in the early project process. In this way better information is available earlier to make better informed decisions at a moment where there is still a significant ability to influence the project.

However, research has indicated that using BIM could shift the workload to an earlier phase of the project without always having the benefits of influencing the project. Many project participants are only involved after a certain point in the process. These partners (for example suppliers) don’t have an interest in delivering information earlier in a project without guarantee of a stable process.

This situation creates a lock-in. Certain project partners cannot invest in providing information earlier in the process because the risk of changes in the project is too high. Evolving these partners as ‘advisers’ means they have to be paid for their advice, independent from their role in the project.

A solution could be to deliver an advise to the project based on knowledge rules. An automated expert system could analyse the project data and send back an automated result. This eliminates the costs of human involvement.

By having ‘bots’ (automated expert systems) analysing the data every time there is a (significant) change of the design, the provided results could actually steer the design team. When the information from the bots is provided within minutes, the design team can use the provided information to change and experiment with the design.

In the current process, energy analyses are only done at the last minute before a permit is needed. By using automated bots to perform a (high level; indicative) energy analysis every time the design changes, the designer can use this to optimize the design. Other performance analyses like CO2 analyses, fire safety simulations or logistic optimizations are barely conducted in a project these days (even in BIM projects). By providing an automated bot for this the costs to perform such a simulation can be very low. This lowers the threshold to use these simulations earlier in the project, and even opens opportunities for expert opinions that could never be given so early in the project.

6 DDSS 2016 1.4 MCA

In the ELASSTIC project an extra element is added: the Multi Criteria Analysis. The focus of the ELASSTIC project is to make the simulation models available during the design of a building. In this way the design can be optimized for safe and secure buildings. When multiple simulations are available on the BIM data of the design they need to be compared against each other. Some design decisions may have a positive effect on the evacuation simulation, but a negative effect on the fire safety. The MCA technology creates an interface on the overall view of the different simulations of the design.

Figure 2. Screenshot of the Flooding scenario evaluation.

2. DATA

The Proof of Concept of the approach and developed tools will be done by evaluating the design of a multifunctional, resilient, large scale urban complex called the ELASSTIC complex. This fictitious complex is designed in the project. The building program of the ELASSTIC design complex contains six modules: offices, museum, theatre, hotel, housing and commerce. In addition there is a fifth building block with the function of parking below the ground level.

Figure 3. Schematic overview of the building program.


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The building model in ELASSTIC was split into 5 different sections. The

5 sections together formed the whole building. Within the 5 sections discipline models were created for the disciplines Architecture, Construction and MEP.

In total 32 revisions were checked into the ELASSTIC BIM server during the creation of the first design. In the final revision of the first design, the total number of BIM objects that was created was almost 20 million.

3. DATA FLOW

Within the ELASSTIC EU project several simulation models use BIM data for their simulations. Before the start of the project these simulation tools had little or no input option for BIM data. The simulations had their own (proprietary) input interface. The biggest challenge was to create a connector to read BIM data to feed the simulations. For reasons of consistency and durability the open BIM data standard IFC was chosen as the interface to BIM data.

Different simulation models need different structured IFC input data. For example the simulation of the evacuation has a strong focus on getting data about staircases, hallways and spaces. For this simulation there needs to be a semantic difference between different spaces like an office, a hotel room, a hallway and an installation shaft. The structural integrity simulation does not have any focus on spaces, but needs information about materialisation, stability principles, etc.

During the ELASSTIC project the development of the simulation requirements and the modelling of the BIM was done in parallel. Therefore the requirements of the input data for the simulation models was not always available for the BIM modellers during the modelling.

To further enrich IFC data with additional semantics, so called ‘classifications’ can be used. In IFC a space is modelled as an ‘IfcSpace’ object. This can be any kind of space. To detail the semantics of a space it can be classified as an ‘office’ or ‘hallway’. This classifying can be done with terms that the BIM modeller just makes up, or a project team agrees to use one specific. For efficiency reasons standardized classification references are used. There are many efforts to map the different classification systems, or to make one overall classification system that replaces all others. These initiatives have not proven to be stable nor effective yet and are therefore not used during the ELASSTIC project.

The services that run operations on data in the ELASSTIC concept also have specific requirements. An example: the explosion model needs to know

8 DDSS 2016 which walls are loadbearing; need specific (detailed) properties of the glass and can only handle tessellated geometry (without Boolean operations). This is a kind of MVD, although it is not officially registered as a BuildingSMART MVD.

To define a specific MVD a new standard is in the making: mvdXML. This is an XML syntax to define a specific MVD for your own software tool. During the ELASSTIC project the mvdXML development was followed with high interest. Both theoretical desk research, as practical implementations have indicated that the current mvdXML development cannot be used to define MVDs for the tools used in ELASSTIC.

During the ELASSTIC project a new version of BimQL (Mazairac, Beetz, 2013) has been developed to solve these issues. Using a query language to replace the concept of MVDs showed to be a valid approach.

At the end of the ELASSTIC project the project partners found that the MVD concept and/or query language should also be capable of performing rudimentary geometric operations. During the ELASSTIC project we experimented with this and this was brought to BimQL as an addendum to the original consideration.

4. ELASSTIC SETUP

In the ELASSTIC project several services were used to perform operations. The setup is shown in the next image:

Figure 4. Schematic overview of the Elasstic BIM data flow. At the core of the workflow a BIMserver.org (Beetz, Berlo et al 2010)

instance is used (with the bimvie.ws GUI plugin). When data complies to


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certain model checks, triggers are send out to a clash detection service; a furniture placer; a validation checker; a simplifier; and the explosion simulation. These services can then trigger the evacuation simulation; a (very simple) fire simulation and a COBie exporter. In the end several services can update the viewer. The MCA link is not shown in this picture.

During the ELASSTIC project we found that there can be several returning loops in this setup. By using correct model checks these loops will not be triggering each other into an endless loop.

As you can see in the image, several ‘support’-bots were used to adapt the BIM data and make it available for the simulation models.

The ‘simplifier’ service, the validation checker and the furniture placer are all examples of implementations that perform automated actions on data to make it suitable for the simulation models.

5. SIMULATIONS

The simulation models used in ELASSTIC are: 1) Explosion simulation: simulating damage after detonation of an

explosive inside or outside near the building. Results can be chance of survival per room; broken windows; etc.. The expertise from TNO was used in this simulation.

2) Pedestrian stream / Evacuation simulation: simulating the stream of people leaving the building. Result of the simulation can be the time that the whole building is evacuated; locations in the building that obstruct a smooth evacuation; etc. The expertise of Siemens was used for this simulation.

3) Earthquake simulation: this simulation calculated the structural integrity of the building after an earthquake. Result is a Boolean if the building still stands or not. The expertise of Schüßler-Plan is used for this.

4) Structural simulations: this simulation calculates the deformations and stresses. The results are used for analyses of impacts from strong winds due to climate changes. The expertise of Arcadis is used for this.

5) Energy simulations: simulation of the energy use of the building. The expertise of Arcadis is used for this.

10 DDSS 2016 6. POST PROCESSING DATA TO FACILITATE MCA

The MCA tool for ELASSTIC doesn’t only require data from the simulation tools, but also needs information about the building itself. This could be the ratio between usable area and technical area, number of building storeys, etc. This information is not available as an attribute in the IFC data, but can be derived from the data. To facilitate the MCA tool, BIMserver created an internal service that analyses the IFC data and calculates the information required for the MCA tool. This information is stored in a JSON file as extended data (just as the simulation results).

Figure 5. Example where BIMserver aided the MCA tool is by creating a

custom made serializer to visualize the building using Cesium.js

7. MCA EVALUATION

The MCA software tool (http://mca.surge.sh) is provided as an open source web application (https://github.com/TNOCS/MultiCriteriaAnalysis). The tool is programmed in the TypeScript programming language and makes use of open source libraries such as Angular.js and Cesium.js.


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The home tab is the first screen of the MCA tool. This tab allows the

user to create, edit, import and export projects. Additionally, the system breakdown is defined in this tab. In the system breakdown all components of the system should be listed. In other parts of the MCA-tool the user can assign weights and scores to each of the components.

Figure 6. In the home tab the system breakdown can be defined. Finally, each component is assigned a unique ID. This ID is used for

identifying the components in other parts of the tool, such as the 3D-visualization. In the scenarios tab, the user can define scenarios that should be taken into account when evaluating the building. Each scenario can be assigned a rating according to its importance, as shown in figure 7. Scenarios can also have sub-scenarios, which is useful when a scenario can occur at different locations. The structure of this tab is similar as for the criteria tab. Again, a pie-chart is used to visualize the weight distributions between scenarios.

Figure 7. The scenario tab.

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The tool automatically calculates the scorings for the designs (in the

Solutions tab). When two solutions are selected, the Comparison tab can be used to compare scores of both solutions. Also, the total scores per module are calculated and displayed in this tab.

Figure 8. The comparison tab.

8. OBSERVATIONS

The ELASSTIC BIM concept proved to have great potential to the industry. Due to the automation of simulation models (with or without supporting services) the designer is provided with direct feedback of the performance of the building during the (early) design phase.

To optimize the usability of this concept additional features are introduced like model-checking, pre-processing of data (called ‘supporting services’ in this report), post processing of data (in this project to facilitate the MCA tool), advanced query/filter functions, etc.

These additional features facilitate the usability for simulation tools to use the ELASSTIC BIM concept, and BIM in general.

9. CONCLUSION AND DISCUSSION

The ELASSTIC project provided the following conclusions about the ELASSTIC BIM concept, the experiments and BIM in the industry:

1) There are numerous possibilities with the concept of automating simulations based on BIM data. At this moment there are still a lot of manual steps necessary. The potential of the concept is proven, but bringing it to (daily) practice will still be a big challenge.


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2) These innovations are only possible with stable open standards

(both data and API) and modelling agreements. During this project modelling agreements were made in the beginning of the project, but not honoured during the implementation. Several elements of the IFC where not usable for the simulation models. Good modelling and good export settings are an absolute requirement to use BIM in general, but the automated simulation concept of ELASSTIC in particular.

The use of open standards like the BIMSie API and the IFC data standard have proven to work when modellers keep to the agreements during the modelling of the BIM in the native software tools.

3) Not all software tools in the industry have the capability to support open BIM standards. We recommend every software vendor to support import and export of IFC.

4) The spread out use of classifications caused a problem with running simulations. The models in the project contained at least three different classifications (a French one, Omniclass and NlSfb). The use of multiple classification methods for objects in BIM is not a problem (and sometimes even recommended), but in this case only parts of the model were classified. Different parts were classified with different classification methods and there was no overlap between it. We highly recommend to classify as much objects as possible, with as many classification systems as needed. The accent is on the words ‘possible’ and ‘needed’.

5) Different simulation tools need different data as input; structured in a different way. Advanced BIM users in the industry know this and export several IFC files with different export settings for different collaboration partners. The ELASSTIC BIM concept doesn’t imply knowledge of the input requirements of simulation tools. Therefore there has to be one export setting to facilitate all simulation models. Use of pre- and post-processing services could contribute to the usability, but this still has to be proven in practical use-cases with large amounts of data and different time scales in execution.

10. REFERENCES

Bektas, Esra. 2013 Knowledge sharing strategies for large complex building projects. TU Delft

Berlo, L. A. H. M. van, Beetz, J., Bos, P., Hendriks, H., & Van Tongeren, R. C. J. (2012, January). Collaborative engineering with IFC: new insights and technology. In 9th European Conference on Product and Process Modelling, Iceland.

Berlo, L. A. H. M. van, & Bomhof, F. (2014). Creating the Dutch national BIM levels of development. American Society of Civil Engineers (ASCE).

14 DDSS 2016 Beetz, Jakob, Léon van Berlo, Ruben de Laat, and Pim van den Helm. 2010 "BIMserver.

org–An open source IFC model server." In Proceedings of the CIP W78 conference. Beetz, Jakob, et al. "Towards an open building information model server." Proc. of the 10th

International Conference on Design & Decision Support Systems in Architecture and Urban Planning, The Netherlands. 2010.

Beetz, J., van Berlo, L. A. H. M., de Laat, R., & Bonsma, P. (2011). Advances in the development and application of an open source model server for building information.

Mazairac, W. and J. Beetz, 2013, "BIMQL – An open query language for building information models", Advanced Engineering Informatics 27(4), p. 444-456.

Sacks, Rafael, and Silvio B. Melhado. "Key performance indicators to analyze and improve management of information flow in the BIM design process." Proceedings of the CIB W78-W102 (2011).

Vullings, H. J. L. M., Vermeulen, C. J., & Kleermaeker, S. D. (2011). Serious Gaming: Training for Disaster Management.

Vullings, H. J. L. M., Kleermaeker, S. D., & Vermeulen, C. J. (2011). Development of a Distributed Simulation Environment for Crisis Management Training. In 2011 International Simulation Multi-Conference ISMC'11, Euro Simulation Interoperability Workshop (E-SIW) 27-29 June 2011, The Hague, The Netherlands, 17-21. Simulation Interoperability Standards Organization's (SISO).

Zhang, C., J. Beetz, and M. Weise, 2014, "Model view checking: automated validation for IFC building models." eWork and eBusiness in Architecture, Engineering and Construction: ECPPM.

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