W3-ABM-Justifying the adoption of BIM processes during project tender stage using Non Compensatory decision making models

  1. Problem Recognition

THE Introduction of BIM process into Design and Constriction work flows provides both Owners and Contractors with many advantages however during the tender stage, an owner must decide between use of traditional design and documentation methods or investment in more detailed modeling (BIM) which requires highly specialized management systems and software.

2. Development of Feasible Alternatives 

An owners tendering strategy is dependent upon a large number of factors. For this exercise we will consider typical Design-Bid-Construct scenario using either of the following methods;

Alternative 1 – Owner developed 2D design format with typical project information including detailed archi, Structure, and MEP drawings, BoQ, material/equipment specifications, site data, etc

Alternative 2-Fully developed 3D design and BIM model including co ordinated structural, architectual, MEP designs inclusive of materials and element specifications plus model generated BoQ, site data, etc

3. Development of the Outcomes

Typical attributes to be used in the comparison of the above alternatives are outlined below.

  1. Simplification of design process
  2. Reduced Cost to prepare Tender documentation
  3. Reduce time to prepare Tender documentation
  4. Accurate representation of Project scope and requirements
  5. Flexibility to evaluate possible design options during tender stage
  6. Reduce risk of variations from Contractor

Within this example, there are no monetary or time figures available for the evaluation the alternatives.The following Non compensatory models will be used as the method of comparison;

  • Dominance
  • Lexicograph

Perceived strengths and weaknesses of each alternative shall be used in the assessment.  Some of the advantages BIM is considered to offer over traditional design and documentation processes include;

4. Selection Criteria

The alternative which is considered dominant will be considered as the preferred alternative however if a dominant alternative cannot be determined, a Lexicograph model based on a ranking of attributes will be used.

The ranking shall be based on the preferences / criteria listed in table 1 (Paired Comparison)

In the above example, the owners priorities are to minimise costs for the development of the Detailed design as well as ensuring that the information provided during tender is accurate and represents the project scope. Based on the rankings, second is the Owners desire to reduce risk of unknowns and variations from the Contractor.

5. Analysis and Comparison of the Alternatives

An Assessment of Dominance among alternatives is outlined in below table based on perceived advantages and disadvantages of BIM process.

A dominant alternative cannot be identified with BIM considered to be superior in only 4 of the 6 attributes.

Under the lexicograph model and the ranking of attributes traditional design processs are determined to

From the ranking of attributes, Cost to develop tender design and Accurate representation of Project scope / Owner requirements are considered priorities to the Owners tender process. This is followed by Owners priority for a reduction in risk of variations (due to poor scope definition).

Whilst tradition tender and 2D design process is considered better in achieving the clients objective of simplifying the design process, BIM can offer a more accurate representation of the project scope and owners requirements through 3D visualization as well as coordinated design process. Given both of these alternatives satisfy each of the top ranked priorities, final selection may be based upon secondary rankings such as  reduction in risk of variation from Contractor due to poor scope definition.

6. Selection of the Preferred alternative

Alternative 2 (BIM Process) is considered the preferred alternative on results above.

Whilst the BIM model development process during tender stages is considered more complicated and costly (Attribute 1 & 2) with a heavy / early reliance upon specialized BIM management skills, BIM will greatly increase the chance of the Owners design and project objectives being satisfied through through better visualization of requirements. The Owners desire to reduce variations though poorly detailed or communication of Work scope is also more likely to be realised with a BIM process.

7. Performance Monitoring and Post evaluation of results

In order to truly evaluate the effectiveness of BIM during the tender stage, the following information would need to be established at the end of the project;

  • Quantity / Value of variations claimed due to scope omission/errors
  • Number NCR’s or rework required by contractor due to non conformance with Specification
  • Compliance with Owners tender design
  • Redesign costs and time lost due to changes
  1. What is Building information Modelling and what are its advantages and Disadvantages (Krigh Bachman) retrieved from www.quora.com
  2. The Benefits Of BIM For Structural Engineers (Venu Gopal) retrieved from www.leevenspark.com/2015/01/the-benefits-of-bim-for-structural.html
  3. 15 advantages of using BIM (Francesc Salla) retrieved from    http://blog.visualarq.com/2014/03/12/15-advantages-of-using-bim/
  4. Sullivan, William G., Wicks, Elin M. & Koelling, C. Patrick. (2014). Engineering Economy 16th edition page 600 -607, England: Pearson Education Limited.
 

W3_TH_ Gas Station Prime Mover Selection by Using Multi Attribute Decision

  1. Problem Definition.

There are three types of prime mover commonly used on gas station project: gas engine, electric motor and diesel engine. This prime mover used to driven CNG compressor. By using multi attribute decision, we can choose the best option for gas station project.

  1. Identify the Feasible Alternative.

Summary data of three prime mover types:

Table 1 Prime Mover Data

There are six criteria of evaluation known as attribute. Selection of prime mover types will use both methods of multi-attribute decision: non-compensatory model and compensatory model.

  1. Development of the Outcome for Alternative.

3.1.    Non-compensatory model.

Four non-compensatory models that will be used: (1) dominance, (2) satisficing, (3) disjunctive resolution, and (4) lexicography.

To check for dominance in Table 1, pairwise comparison of each prime mover`s set of attributes must be inspected, as shown in Table 2.

Table 2 Evaluation of Dominance

Based on Table 2, we know that no prime mover is dominant than others.

To illustrate the satisficing model, acceptable limits must be established for each attributes.

Table 3 Evaluation of Satisficing Model

No alternatives that are eliminated on this models, shown by Table 3.

Table 3 also is used to evaluate the disjunctive resolution, where concluded that all alternatives is acceptable because each has at least one attribute value that meets or exceeds the minimum expectation.

To conduct lexicography, the first step is to rank each attribute, as shown in Table 4.

Table 4 Attributes Ranking

Table 5 shows evaluation using lexicography, where “Electric Motor (A)” has highest rank attribute.

Table 5 Lexicography Evaluation

 3.2.     Compensatory model.

In this evaluation, two compensatory models, that are the non-dimensional scaling and the additive weighting technique will be used.

Ranking attribute by using non-dimensional scaling as shown in Table 6.

Table 6 Non-dimensional scaling (NDS)

As shown in Table 6, alternative “Electric Motor (B)” has highest rank

After set relative rank for each attribute, further is to conduct additive weighting for all alternatives as shown in table 7.

Table 7 Additive weighting evaluation (AWE)

Note: Column Relative Rank is taken from Table 5.

As shown in Table 7, alternative “Gas Engine (A)” has highest rank.

  1. Selection of Criteria.

A selection criterion for prime mover selection is the highest rank.

  1. Analysis and Comparison of the Alternative.

Table 8 shows ranking of prime mover that resulted from both non-compensatory model and compensatory model.

Table 8 Ranking of Prime Mover

As shown in Table 8, it is interesting to see that both methods result the different rank order, where on Non-compensatory model and Compensatory model NDS: “Electric Motor (B)” has rank number I (highest) followed by Gas Engine (A), and Diesel Engine (C). Different with Compensatory model AWE result: “Gas Engine (A)” has rank number I (highest) followed by Diesel Engine (C) and Electric Motor (B).

  1. Selection of the Preferred Alternative.

Electric Motor will be decided as prime mover type for the gas station project. But if the delivery time and OPEX (as shown by rank Table 7) be the main concern, the best choice is Gas Engine.

  1. Performance Monitoring and the Post Evaluation of Result.

To ensure that all requirements are met, monitoring should be conducted during execution of the project.

References:

  1. Sullivan, W.G., Wicks, E. M., Koelling, C. P. (2014). Engineering Economy, Chapter 14, page 559 to 617. Pearson. Sixteenth Edition.
  2. Planning Planet (2017). Multi Attribute Decision Making. Retrieved from https://www.planningplanet.com/guild/gpccar/managing-change-the-owners-perspective
  3. W3_MFO_Gas Meter Selection by Using Multi Attribute Decision. Retrieved from https://emeraldaace2017.com/2017/08/15/w3_mfo_-gas-meter-selection-by-using-multi-attribute-decision/
  4. W17_YAW_Licensor Selection by Using Multi Attribute Decision. Retrieved from https://kristalaace2014.wordpress.com/2014/06/19/w17_yaw_licensor-selection-by-using-multi-attribute-decision/
  5. W4_Andi_Decision Making Multi Attributes. Retrieved from https://kristalaace2014.wordpress.com/2014/03/21/w4_andi_decision-making-multi-attributes/