Optimizing Design and Construction through BIM Technology
Every architect or engineer who designs gives consideration to efficient use of materials. Whether a rocket scientist or a child building a sand castle at the beach, the process of exploring the limits of a material are part of the fun of the process. Let’s consider something between a rocket and a sand castle – say a bicycle. If your task was to design a steel bicycle frame, any one of us could rig something together that would work. But if we add the requirement of making the most efficient design possible, then your job would become much more complex.
Design Optimization Over – designing may be quick and easy, but it invariably wastes materials. Can we cut the weight of our overdesigned bicycle in half and still meet performance requirements? By applying skill and analytical tools to the design process, we can maximize performance without unnecessary material waste.
Of course there are practical limits. I will never forget a poster that hung in the office of the first engineering firm I worked for which said, In every project there comes a time to shoot the engineers and start production. We don’t have unlimited time to optimize designs so we use factors of safety, make safe assumptions and live with a good enough ethic to produce reasonable solutions.
Just as we can optimize a design, we can also optimize a process by applying skill to reduce time, increase yield and reduce waste. Here again, the constraints of time lead us to settle for processes that are good enough to keep production moving forward. With all this in mind, let’s take a look at the masonry construction process and see how BIM is changing the way things are done.
Simplifying for Accuracy Generally, the more complicated a problem or process is, the more likely we are to make assumptions and tolerate a measured margin of error. Masonry, especially architectural masonry, is in a class of its own when considering the complexity of ordering, manufacturing and installing such an elaborate puzzle of material. We are not talking about a simple count of windows, doors or fixtures, nor are we talking about stock material or ready-mix concrete which are comparatively easy to manage.
For any project that does not use stock material, it is necessary to accurately order material at least 4-to 8-weeks prior to delivery. A limited time to perform a complex task. Contractors have two options: short order and hope there is enough time and resources to place the necessary add orders, or over order and hope the order is accurate enough to cover the requirements.
Usually, some combination of the two happens. In the absence of a reliable way to optimize the ordering process, it has been the accepted good enough solution for decades.
Here lies a great opportunity for the masonry industry. If this process could be improved, then a notable shift toward efficiency could be achieved, ultimately driving down the cost of masonry.
That would be good news! BIM is proving to be an effective process optimizer and when applied to masonry, it is exactly the tool the industry has been looking for.
Competitive The advent of reliable construction modeling tools for masonry is very good news for the entire industry. In the construction phase, models capable of accounting for individual units that accurately depict bond patterns can deliver extremely accurate orders. Based on case studies we have followed in more than 10 years of preparing these models, it is not unusual for a non-modeled order to have 10% or more of the material cost built in to cover these inefficiencies – some are closer to 20% of the material cost.
An order that is properly modeled often has no add orders and only the waste calculated for breakage and handling. Recouping that cost alone makes masonry noticeably more competitive. Modeling a masonry order also carries with it a degree of confidence in the integrity of the order due to its visual nature. If a model is wrong, it is visually obvious and very easy to validate for accuracy. An accurate model produces an accurate order, reduces material congestion on site, keeps unnecessary trucks off the road and conserves resources.
Smart Model Identification These masonry models are not only more accurate, they are more complete. If a job requires a special masonry unit with an unusual combination of finished faces or edges, a smart model will identify it. Accurate modeling is a very thorough process that simulates as-built conditions allowing for proofing of the plans much earlier in the game.
The modeling process generates Requests for Information (RFI), identifies special units that may typically be missed and occasionally exposes design flaws while there is still time to adapt. The upshot is a higher quality masonry installation with fewer field cuts allowing greater efficiency. That’s good news for the architect and owner as well as the contractor.
Manufacturers also reap rewards. Over ordering often leads to pallets or even truck loads of overproduction. What happens to that material? Often, it winds up sitting in the production yard or is written off as a loss, thereby straining relation – ships with customers. Conversely, small add orders are inefficient uses of equipment designed to produce in bulk. For these reasons, it’s often the manufacturer who initiates the use of BIM services for architectural masonry jobs. And there is still more in it for them.
Modeling for masonry is getting faster and faster, so a modeled order will often be ready for production sooner, relieving the pressure of getting product to the jobsite on time. Models display unit codes that correlate to the manufacturer codes so there are fewer errors in production. It is also easy to generate sub orders from a model based on the planned installation order. This allows a manufacturer to make the required product in the proper order. For jobs that require grinding or other secondary operations, this alone can make the difference in meeting a delivery schedule. Models improve everything from customer relations to how trucks are loaded in the yard.
More Informed Design Process Masonry models are currently being used for clash detection on jobs with full BIM requirements. Experience shows that masonry models are often the geometric standard when clashes occur due to their modular nature. Since these models account for individual units and are aware of their relationship to the bond pattern, they accurately reflect unit layout. This is useful in verifying that openings in the wall are consistent with the bond. Small adjustments to window and door locations are often the result of using a smart masonry model. If field cuts are required either to maintain bond or to locate openings, they can be properly identified and quantified in the model. Drawings showing the full bond layout produced from the masonry model help reduce labor costs for the contractor installing the product.
Executing Design Intent Looking at a recent example that used a smart masonry model helps illustrate the concept. Los Angeles Valley College’s new athletic training facility includes two main structures and multiple satellite structures such as storage buildings, site walls and dugouts. All structures use single wythe loadbearing masonry with 8″, 10″ and 12″ concrete masonry units (CMU). Architectural masonry provides exterior finish as well as some locations of interior finish.
Seismic requirements dictate: a) grouted reinforcement steel at 16″ oc both horizontally and vertically so stretchers are double-open end bond beam units, b) all corners and jambs are no-center-web- ring block to allow for proper grout flow and efficient installation with the maze of rebar.
Most CMU are standard ASTM C90 (1900 psi), but there are a few high-stress locations in each bed depth ( f’m = 2500 psi). By using a limited amount of high stress units, various sizes properly placed reinforcement and a variety of color and texture, this project capitalizes on many of the assets of masonry for an optimal design. In doing so, the masonry order needed to be very specific, making it perfect to high light the value of using a BIM for masonry solution.
Mason contractor Masonry Concepts had prior positive experience using BIM models for masonry, so smart models were employed again. This model contained 24,360 CMU, had 47 unique combinations of color, strength, shape and texture, and took three days to complete. After a process of review and revision, material was ordered.
The model identified a dimensional anomaly in the alignment of two walls allowing it to be addressed very early in construction. A complete order and seven sub orders were derived from the model to aid in production and material staging on site. Layout drawings were prepared from the model and should serve to expedite installation. The masonry model was provided to the general contractor for clash detection and integration into a parent BIM project model.
Giant Steps to Efficiency The kind of data generated from projects using models like this one is serving to increase the confidence of everyone involved with masonry. Architects who require and review masonry layouts can be assured that their design intent will be properly executed. Manufacturers receive more complete orders in a timely manner and can execute an efficient manufacturing plan.
Installers can literally see if an order is correct before placing it and they can be much more productive in the field by using detailed layout drawings that show codes, unit locations and bond pattern layout. Markets that embrace BIM technology should see the cost of masonry come down and value engineering of masonry decrease. As model automation improves, this kind of data will become available much earlier in the design process allowing for a much more informed masonry design process.
For masonry, BIM is helping good enough get a whole lot better.
Tom Cuneio, has been developing modeling solutions for masonry for over 10 years. His company, CAD BLOX LLC has provided models, orders, layout drawings and other BIM related services for over 400 commercial jobs. He is actively developing software and methods to help the masonry industry capitalize on the benefits of BIM technology. He is an honors graduate of the Mechanical and Aerospace program from the University of Missouri. 719.232.5570 | firstname.lastname@example.org