JUNE 2, 2014
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SIX-YEAR WATER FUNDING DROUGHT ENDS
MIAMI MUSEUM SWAPS OUT CONTRACTORS
BULLITT CENTER BEATS ENERGY GOAL
TEST DRIVE: GMC’S NEW LUXURY PICKUP
SAFETY
ENR FUTURETECH SPECIAL REPORT
BY DESIGN
PREDICTING AND
AVOIDING JOBSITE
RISKS WITH
4D PLANNING
DYNAMIC MODELS
FOR SAFER SITES
J
obsite safety is an ongoing challenge. As preplanning gives
way to activities and construction moves through its phases,
the site, crews, equipment and logistics erupt into dynamic
flow. Keeping the workforce and public safe as the project
swirls through its cycles requires that managers be vigilant
analysts, aggressive contingency planners, flexible adjusters,
great communicators and effective safety trainers.
Contractors say having a clearer picture of how the project will unfold
is key to reducing safety risks; four-dimensional building information
modeling helps reveal them. Such models create animated sequences that
show a structure’s components­—including permanent and temporary
works, major equipment and laydown areas—according to the timing of
the project schedule, typically the fourth dimension in the model. Planners say 4D BIM helps them coordinate schedules, eliminate conflicts and
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confusion, improve training and enhance safety by
design. The models can help head off spatial conflicts
and safety risks that otherwise might go undetected.
But useful models must be updated frequently.
“It’s not an easy process” admits Scott Kerr, principal BIM integrator at London-based Balfour Beatty
Construction Services, which has maintained a 4D
model through the life of a complex terminal expansion
project at London’s Heathrow Airport. The terminal
is set to open June 4.
BBCS used the project’s Autodesk Revit 3D model
with Autodesk’s Navisworks Timeliner, a schedule
animation program, to build its 4D model. Timeliner
assigns “exclusion zones” to scheduled activities and
IMAGE COURTESY OF BALFOUR BEATTY UK
Construction managers embrace 4D BIM for ongoing analysis and safety
optimization of evolving projects By Tom Sawyer
ENR FUTURETECH SPECIAL REPORT
PHOTO COURTESY OF BALFOUR BEATTY UK
equipment locations, represented as objects in the
model. BBCS updates the model and schedule regularly and runs the 4D simulation each week to create
14-day and 42-day “look-ahead” views of currently
planned activities. Timeliner’s conflict checker searches
out clashes in space and time between equipment and
trades. Activity locations are color-coded in the model.
In the image on the page opposite, structural steel
erection (dark green) is flagged for overlapping the
exclusion zone for concrete placement (light green).
“When we synchronized the schedule with the model
we got that flag,” says Kerr. “Potentially we have an
issue; something has to give.
“I definitely think the value and benefits outweigh
the effort,” Kerr adds. “You have to manage the process, the changes and the things that come from left
field, and the model can help you understand all of
that—but it’s a moving beast.”
Technology Developments
Contractors, construction management firms, academics and software vendors are working on ways to improve and enhance 4D scheduling techniques. They
include automated programs that check 4D models for
risks and safety-code violations, based on rules such as
those prescribing clearance dimensions, equipment
specifications or labor allocations.
In New York City, Jennifer Downey, an architect
who manages support services with Turner Construction’s Integrated Building Solutions group, is collaborating with Fiatech’s autocodes project, city building
officials and the developers of Solibri software’s Model
Checker—a program that analyzes design models for
dimensional compliance with building codes and regulations—to flag safety issues during construction.
The Model Checker software runs against a BIM
database of thousands of elements in a model tagged
RISK
AVOIDANCE
A big conflict
between scheduled
steel erection and
concrete work on
Balfour Beatty’s
Heathrow Terminal
2 project was
flagged by a 4D
model checker.
“Something had
to give.”
“It’s not an easy process. But I definitely
think the value and benefits outweigh
the effort. —Scott Kerr, BIM Integrator, Balfour Beatty UK
with the project’s OmniClass Construction Classification System, or Uniformat, numbers. This identifies
an item, such as a men’s room—classification number
13-23 17 11—and the associated regulations that apply,
such as Americans with Disabilities Act compliance
dimensions. The Model Checker flags unclassified
objects, as well as objects that fail to meet regulations.
Downey has been modifying Solibri templates to
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Mortenson
Construction used
4D simulation to
analyze the structural requirements
needed to build a
mechanical penthouse atop an office
building in Denver.
It helped address
safety challenges of
erecting a two-story
scaffolding system
cantilevered over a
25-story drop.
set up runs for construction projects in their various
phases, such as excavation or steel erection. She is tagging construction site objects in the model, such as slab
edges, openings, gates, flaggers, materials storage
points, portable toilets, and fire and life-safety features,
to which rules apply on a construction site.
“There is a very long list of requirements for jobsite safety from different international and local
authorities, as well as Turner’s own requirements,”
Downey says. “I took the standard rule set and
modified it to be safety-related. We have identified
137 items that could be reviewed in a modeling environment.” In the process of modeling they are getting
quantities for safety materials, such as linear feet of
edge-protection netting.
“If these 4D safety observations were
fed back into the schedule from the
beginning we would have had a much
greater grasp of sequence and duration.”
—Steve Moore, district planning manager, TIC
One early payoff is in verifying the correct placement
of fire extinguishers of the proper classifications, which
are to be positioned within 75 ft of one another in plain
sight, provide full coverage of every floor and be located
within 10 ft of stairways. “For something as simple as
fire extinguishers there are a lot of requirements that
come into play,” Downey says. Running the checker
against the model with fire extinguishers in place verifies
their correct placement in the plans.
Mojtaba Taiebat, a Georgia Tech researcher now at
DPR Construction, also is developing rules that could
be used with compliance-checking software like Solibri
for job-hazard analysis and to flag potential falls by
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analyzing openings in unfolding 4D models.
Taiebat proposes his checker be used as part of a
collaboration between designers and constructors in an
integrated project-delivery format as early as conceptual modeling as part of a “design for safety” concept.
He says a detailed schedule is not required at that stage,
but modeling work locations, scaffolding, formwork,
material delivery paths, openings and edges would be.
“The model represents contributing factors of fall
hazards and prone-to-error conditions,” he explains.
Once those factors are simulated and shown to the IPD
team, hazards can be reduced through design alternatives, changed construction methods or changed
scheduling, based on the team’s experience.
The Great Communicator?
And then there are managers who say when teams of
designers, contractors and subs watch planned work
unfold on screen together they are motivated. As they
see objects representing equipment and materials
coalescing through time, they not only pick up on previously hidden conditions such as conflicts between
unrelated activities, but they also understand and resolve issues better in advance.
“When you look at the site and say ‘here is what it’s
going to look like next week and here’s what’s going to
happen,’ people are going to watch a video because it’s
cool,” says Ken McBroom, chief scheduler at McCarthy
Building Companies Inc., Newport Beach, Calif.
McBroom cites a hospital project where he used 4D
project management software Synchro Professional to
animate the CPM schedule. That is when his plumbing
contractor realized that planned roadwork would block
a critical delivery, which was quickly rescheduled. “The
plumber is not looking at the schedule of the curb-andgutter guy. It’s not his problem,” says McBroom. “That
happens a lot because two things don’t seem to fit together.” But in a 4D visualization, they do.
IMAGES COURTESY OF MORTENSON CONSTRUCTION
SAFETY POINTS
ENR FUTURETECH SPECIAL REPORT
BUSTED
IMAGE COURTESY OF SOLIBRI INC.
A rules checker run
against a model of a
Turner Construction
project discovers the
plans show no fire
extinguisher within
10 ft of a stairwell, as
regulations require.
“It is difficult and time-consuming to communicate
a complex construction plan using traditional tools,”
adds Steve Moore, southern district planning manager
for TIC, a Kiewit-owned heavy industrial contractor.
“Safety personnel do not have time to study stacks of
drawings or a 5,000 line-item schedule. It gets even
more complicated to visualize the plan as field conditions constantly evolve and change during the project,”
Moore says, “[But] 4D gets everyone up to speed on a
complex project very quickly, with detailed imagery.”
Moore says safety now plays a larger role in planning before the project goes to field. He says it is
surprising how a safety person can view a 4D construction plan in a totally different way than the rest of the
team. “They are instantly visualizing the required fall
protection, dropped-object hazards, eye-wash station
locations, etc.,” he says. “We now get detailed and substantive feedback from our safety department during
early construction planning, which shapes the way that
we approach our projects.”
On one recent powerplant project where TCI used
Synchro for 4D modeling, Moore says “the 4D model
made it clear that our scheduled plan was not factoring
in safety.” Activities were being scheduled literally on
top of others. When corrections were made the project
ended up taking much longer than originally planned.
“If these 4D safety observations had been fed back
into the schedule from the beginning we would have
had a much greater grasp of the sequence and duration
of this work,” Moore says. “With 4D, we can now
catch these issues in our schedules years ahead of their
occurrence, allowing us to create better and more realistic plans from the beginning.”
Jay Mezher, director for virtual design and construction at Parsons Brinckerhoff, says leveraging 4D
BIM for safety follows an innovation trail he has seen
with the use of computational fluid dynamics for modeling ventilation in tunnels, and evacuation modeling.
Widening Use
Doug Rowe, general manager of the Lend Lease integrated project group, says Lend Lease routinely uses
4D BIM to model and simulate detailed safety and
logistics plans during risk analysis throughout projects.
He predicts that as the technology becomes more userfriendly, 4D BIM for detailed installation simulations
will become more common “and will clearly drive safer
and more productive workflows on all construction
projects over the coming years.”
McCarthy’s McBroom says better 4D planning not
only makes jobs safer but also communicates planned
activities better to all stakeholders in a project, including the owners and the public. “Planning on the fly is
the same as not having a plan,” McBroom says. “That’s
just reacting. When you are trying to plan on the fly …
that’s usually when something goes wrong.”
McBroom says one scenario in which he intends to
use 4D modeling to enhance safety is during mixed-skin
construction on multi-story buildings. The company
just finished one such project. It tracked the day-to-day
work locations on the face of the building of trades doing masonry, framing, panel installation and glazing
with color markers on isometric 2D plans day after day.
He said he realized as they wrapped up the project that
modeling those locations using 4D would help ensure
that no activity violated one of McCarthy’s fundamental safety rules, which is that if crews are working overhead, nobody is underneath.
“The application of 4D to that is perfect. I don’t
have to look at a CPM schedule and try to imagine
775
CONSTRUCTION
FATALITIES IN
THE PRIVATE
CONSTRUCTION
SECTOR IN 2012
SOURCE: BLS
2x
INJURY RATE
FOR HISPANIC
WORKERS, VS
NON-HISPANIC
WORKERS
SOURCE: LOPEZ DEL
PUERTO ET AL., IN-PRESS
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FORSIGHT After running
where every crew is; I can look at the[4D] representation of the model at any point in time and see what
crew is working on what level. That would be a great
application of 4D and safety,” McBroom says.
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Safety, Translated
Experts say visualizations can be very effective for communicating life-safety information—especially to nonEnglish speaking workers.
Ricardo Khan, director of integrated construction
at Mortenson Construction, is working with Caroline
Clevenger, an assistant professor at Colorado State
University, to draw site- and task-specific bilingual
visual training tools directly from 4D models of
planned activities. They are starting with scaffold erection, with its significant fall hazards, and are visually
drilling into the activities to train novice and non-English speaking construction workers, whose injury rates
far exceed other categories. Clevenger notes also that
Hispanic construction workers are twice as likely to
get injured on the jobsite as non-Hispanic workers.
She says research suggests the higher injury rate is due,
in part, to language and cultural barriers on the jobsite.
“I would like to see future efforts of 4D modeling
begin to focus on a micro level,” says Ryan Poropat, a
Mortenson superintendent who recently used 4D tools
on a sports and entertainment center in Buffalo, N.Y.
Their efforts are in line with another 4D BIMrelated mission of Jason Reece, a Balfour Beatty research and development leader based in Fairfax, Va.
Reece has studied the industry’s long-running failure
to communicate critical safety knowledge about construction risks, such as trenching.
Like Clevenger and Kahn, he sees an opportunity
to improve training through BIM-enabled visual storytelling, which, combined with personal stories about
real incidents, can help create “the written, audio and
visual hooks that make information stick.”
Creating realistic visualizations of high-risk scenarios in the context of the work, and then showing
how hazards should be mitigated, is a powerfuil way to
leverage technology for safety, he says. He suggests
that if safety trainers take advantage of BIM and visualization to improve safety-related storytelling, their
training will have more effect.
“Create the mental hooks for the information;
that’s how people remember and how you are going
to change safety culture,” Reece says. Stories are
information. “If you want to use BIM for safety you
have to learn what makes a good story and what makes
ideas stick.” n
www.balfourbeattyus.com
Get in touch: [email protected]
Excerpted from Engineering News-Record, June 2, 2014, copyright by BNP Media II, LLC. with all rights reserved.
This reprint implies no endorsement, either tacit or expressed, of any company, product, service or investment opportunity.
#C45912 Managed by The YGS Group, 800.290.5460. For more information visit www.theYGSgroup.com.
PHOTO AND IMAGE COURTESY OF TIC
4D simulations, TIC planners realized the schedule
needed modification to keep
activities vertically separated, resulting in a longer
duration than originally
expected. It won’t happen
again, they say.