LG Research-Jiang.pdf

Virtual Prototyping for

Automated, Rule-based Constructability Review

Li Jiang, PhD Candidate; Dr. Robert M. Leicht

L E A N A N D G R E E N: R E S E A R C H I N I T I A T I V E

Background

Constructability is defined as “the optimum use of construction

knowledge and experience in planning, design, procurement, and

field operation to achieve overall project objectives,” (CII,

1986). Frequently, a review of constructability concepts is

adopted by using a checklist and a lessons-learned system after

the design reaches a certain design stage, 30%, 60%, or 95%

design (Hancher and Goodrum, 2007).

However, the large amount of required resources, time and manpower, largely impedes constructability implementation

(Hancher and Goodrum, 2007); the rework in design caused by

the inefficient process (Arditi et al., 2002; Pulaski and Horman,

2005) cannot be ignored either.

As the idea of implementing integrated design methods to

enhance productivity and value in the industry, this research

examines the existing constructability review process and

addresses the research question:

What process changes with the help from integrated design

methods and tools can help to improve the current

constructability review process?

Research Goal & Objectives

To improve consistency, efficiency, and value of existing

constructability review process, by proposing an automated rule-

based constructability review with the implementation of

Building Information Modeling (BIM).

To investigate the feasibility of using available BIM

contents to represent constructability knowledge required

for a constructability review.

To define and validate the method of rule-based checking to

automate constructability review process.

To demonstrate the benefits of the proposed constructability

review process with the implementation of BIM, in terms of

automational, visual, informational, and transformational

effects.

Capturing Constructability Knowledge for Reinforced Concrete Structure

The elicitation of constructability knowledge from construction experts is the first and important step for the research to analyze the

feasibility of using available BIM contents to interpret the constructability knowledge required for a constructability review. Multiple

case studies are being to collect and analyze the knowledge.

Focusing on reinforced concrete structure, one case study, shown in Figure 1, is the Turkish-American Community Center at

Lanham, Maryland. This project has 5 buildings interconnected via an underground parking facility, including a mosque. The

complex has a gross floor area of approximately 316,000 square feet, more than 95% of which is constructed with cast-in-place concrete. One of the 5 buildings has a one-story steel structure, and thus is not considered in this study. Given cultural concerns, the

project design has incorporated traditional mosque features such as domes and minarets, resulting in a range of different formwork

systems used in the project.

As shown in Figure 1, the knowledge regarding formwork decisions captured from project team are compared with available BIM

contents accordingly, demonstrating the ability of using BIM to provide upfront feedback and facilitate early planning and decision-

making.

Conclusions

The automated rule-based constructability review process is

expected to produce significant potential benefits, in terms of

automational, informational, transformational, and visual effects

(based on Fox and Hietanen, 2007):

Visual: Unlike most of previous

constructability tools, BIM owns

strong capabilities of visualization.

With 3D graphic representations,

potential constructability issues can be

easily presented, understood, and

communicated among project

participants.

Automational: Instead of a manual check of printed plans

with a checklist, an automatic review process can be

systematic and comprehensive, reducing the required time

and resources for simpler concerns and allowing the

construction team to focus on future impacts and planning.

Informational: Integrated with 3D graphic representations,

the information embedded in BIM models can be extracted and shared among different project parties. The

informational effects of BIM

implementation allows designers to be

aware of design-related construction

concerns at corresponding design stages,

resulting in “proactive,” instead of

“reactive,” design feedback, and better

decision-making.

Transformational: As the “proactive” feedback is enabled in the

design process, the transformational effects will be through

the change in process. The proposed process is expected to

pull the constructability knowledge into the design process

and encourages designers to produce a more constructible

design.

Future Research

Acknowledgements

Bob Grottenthaler

Barton Malow Company

For additional information or questions regarding this research, contact:

Li Jiang, PhD Candidate

[email protected]

Dr. Robert M. Leicht, Director of PACE, Assistant Professor

[email protected]

Future work can focus on three directions:

Further investigation of constructability knowledge.

Based on limited case studies, the current research merely

investigates the relationship between BIM contents and

structural design-related constructability issues. A com-

prehensive acquisition of constructability knowledge can

be achieved by looking at more case studies or different

design disciplines.

Further development of design-related constructability

rule-sets. Considering the existing technical difficulties

regarding the rule checking platform, the rule-sets

developed and tested in the research are merely about form-

work selection. Further investigation is needed to develop a

comprehensive set of reasoning rules of design-related con-

structability issues.

Further exploration of the proposed process. As existing

technical issues may be solved and the rule-sets become

complete, the process needs to be detailed mapped out

and documented for better practices and collaboration

among different project participants.

Process

PeopleTechnology

Kurt Maldovan

Balfour Beatty Construction

Structural System

Superstructure

CIP Concrete

Seismic Applications

Non-Seismic Applications

Gravity Systems

Normal Reinforcing

Dimension (e.g. height, thickness, etc.)ReinforcingOthers

Sub-structure

Misc. Members and Items

BIM Contents

Architecture System

Technical Systems (i.e. mechnical, electrical, plumbing systems)

Database of Constructability

Rulesets

Lateral Systems

…...

2 Way Flat with Drop Panel

Location

Schematic Design

Design Development

Construction Documents

Figure 1: Implementing BIM for Automated Constructability Review

Knowledge Representation

The representation of knowledge involves analysis of how to

reason accurately and effectively and how to “write” and encode

the knowledge into a form that is understandable by humans and

behave like humans (Brachman and Levesque 2004).

The method of rule checking is applied in this research to

represent the constructability knowledge and to model the ways

of thinking as construction experts in a constructability review.

Figure 2 shows the formwork used in the case study project of

Turkish-American Community Center. In the form of decision

tree, Figure 3 represents the acquired knowledge for horizontal

formwork selection through an interview of project team. In

addition to design parameters such as slab slope and slab depth,

resource constraints such as crane, labor, and the layout density

have been considered in the decision-making of formwork use.

Based on the obtained knowledge, a set of design-related

constructability reasoning rules can be developed to represent the

knowledge and thereby to achieve an automated constructability

checking. Figure 3: Case study interview: horizontal formwork selection

Application: Formwork selection rule testing

An example of reasoning rule is written as (Hanna and

Sanvido, 1989):

“IF: Building size is small or medium (i.e. gross area

is no more than 25,000 sq. ft)

AND: Building height is between 10 to 13 floors

THEN: Use conventional aluminum forming system.”

The reasoning of conventional aluminum forming

system selection at Washington D.C. urban area requires two different attributes- building size and

building height. As a results, the reasoning process can

be divided into 2 parts: reasoning about building gross

area, and building height. As long as both of them

meet the target value, the formwork selection can be

achieved.

Solibri Model Checker, as a world-leading model review software based on rule-based checking, has

been applied as the platform to develop and run the

constructability reasoning rules. More detailed

information about Solibri can be found on http://

www.solibri.com/.

Figure 4, 5 and 6 are snapshots from Solibri, showing

the constitution of the rule-set, parameters of the two

separated reasoning rules, and corresponding target value of each parameter

respectively.

Figure 4: Formwork selection rule example

Rule Execution

As the reasoning rule-sets are defined by writing the acquired

constructability knowledge into machine-readable language, those

rules need to be executed in an appropriate rule checking

platform, in order to prove the validity of the innovative approach.

This part of research will use a case study to test the rule-sets of

formwork selection, as a test case with validated logic to support

means and methods rules. Solibri Model Checker will be used as

the platform for rule execution.

As an example, one case study

project, which is the Copping

State University Science &

Technology Center at

Baltimore, MD, is used here to

test the rule-set of “Horizontal

Formwork Selection.” Figure 7

shows the architectural

rendering and REVIT model of

the project. The rule execution

interface of “Slab Formwork

Selection” in Solibri is

displayed in Figure 8.

Process Modeling

Last, though far from least, a process protocol of an automated

constructability review with the implementation of BIM will be

developed. Based on Eastman et. al (2009), a typical rule-based

reasoning process has 4 stages (Figure 9):

Rule interpretation, which aims to translate the construction

knowledge acquired from industry experts into computer-

readable language, and to form logical structure of rules for

their application as human reasoning. Depending on different

project phase (i.e. SD, DD, CD, and Pre-Construction),

different level of detail of constructability knowledge are

interpreted into related rules and stored in the appropriate

rule checking platform.

Building model preparation, where necessary information

required for the automated rule-based reasoning is prepared.

As design develops (e.g. from SD to DD and then to CD),

appropriate level of detail of BIM contents should be

embedded into the design model at each phase.

Rule execution, which brings together the prepared building

model with the rules that apply to it. At different project

phase, the BIM contents captured by the reasoning rules will

be at different level of detail.

Reporting the reasoning results (i.e. constructability feedback) to designers. Depending on the timing of the

feedback, two types of constructability feedback are

expected to be obtained from the proposed process: reactive

and proactive feedback.

Reactive feedback is provided

by reacting a situation; whereas

proactive feedback is provided

in advance of a situation. For

example, the feedback

regarding the design changes

for fully developed concepts is “reactive;” the feedback that is

provided at the same phase but

mentions constructability

concerns for future design steps

is considered as “proactive.”

The automated rule-based

reasoning process enables

consistent proactive feedback

in the review process, adding

more value to the process.

Figure 7: Case Study Project: Coppin State Sci. & Tech. Center

Figure 9: Overall process of automated rule-based constructability reasoning (based on Eastman et. al, 2009)

Figure 5: Rule parameters of “Building Gross Area”

Figure 6: Rule parameters of “Building Height”

Figure 8: Rule execution for “Horizontal Formwork Selection”

DD CD

ConstructionKnowledge



Pre-ConSD


Database of Rule-sets




EXPERT

USER

❶ Rule Interpretation

❷BIM Model Preparation

❸Rule Execution

❹Constructability Feedback

Reactive feedback

Potential Proactive feedback

SD: Schematic Design

DD: Design Development

CD: Construction Document

Pre-Con: Pre-Construction/Shop Drawing

Notes:

Figure 2: Formwork used in Turkish-American Community Center

http://www.solibri.com/

http://www.solibri.com/