August 20, 2014
At the heart of it all, our industry comes down to teams working together to collectively build something greater than the sum of its parts. From the trade persons on the job site, to the design teams cooped up in their offices, and everyone in between, teams embody every step of the process. When it comes to the design team, nothing makes a project more successful than working together. Architects and engineers might not always speak the same language, but understanding each other’s needs goes a long way to avoid losing your design intent in translation.
With the goal to promote better communication and collaboration between architects and structural engineers, we have put together 10 things that are common issues throughout the life of a project. We have also invited FXFOWLE, one of our teammates on many successful projects, to share their insights on what we as structural engineers can learn from architects.
10 Things Architects Need to Know from Structural Engineers
1. Time is of the Essence
Drafting is only a fraction of the work that must be done to complete a structural design. Most designs require the use of multiple analysis and design software programs, which then need to be interpreted and documented. In short, the more time we have with your backgrounds, the better.
2. It’s a question of scope
A structural engineer’s scope is not always clearly understood. Unless specifically included, only elements of the base building structure, i.e. elements that make the building stand and other primary components, are in the engineer’s scope. Ornamental and miscellaneous metals are typically left to a subcontractor to design and detail.
3. Be consistent
Please try to use consistent settings for the units throughout a BIM model. Changing the settings for different views may be convenient for dimensioning, but it presents a problem when trying to accurately locate structural members. We are engineers after all, and we like to be precise!
4. Size matters
Always try to purge models and remove links to local files prior to posting BIM models. The less time we have to spend cleaning the model, the more time we have to get you what you want.
5. Where to draw the line?
Foundations along property lines can be problematic for many reasons, namely: party wall conditions, underpinning, encroaching structure, and footing eccentricities to name a few. The more distance that can be spared from the property line in the initial design, the more trouble that may be averted during construction.
6. How close is too close?
Age old question: “How far away from the columns can the penetrations be placed so it’s not a problem?” Technical answer: All openings within a distance 10 times the slab thickness (or 80” for a typical residential building) must be taken into account!! Luckily, with a little added reinforcing, interior columns can typically tolerate penetrations on two sides, and perimeter columns can tolerate penetrations on one side, but these locations must be coordinated and maintained.
7. Know when to fold ‘em
Slab folds are a necessity in every project, but architectural and structural drawings do not always agree on where they occur. Smaller slab folds (less than the slab thickness) have more flexibility, however, it is beneficial to locate larger slab folds along column lines as the fold behaves as a beam. Differences in elevation beyond the fold can be made up with Styrofoam and light weight slab.
8. Mind the details
In steel buildings, don’t forget to account for bracing or base plates. These often have large impacts on wall thicknesses and furring, and the sooner they’re addressed and accommodated the better.
9. Location, Location, Location
It is most efficient to locate penetrations through steel beams at mid depth and within the middle third of the span. Limiting openings to approximately one-third of the depth may also eliminate the need for additional reinforcement. As always, it is best to detail such openings in advance and to have them shop fabricated!
10. Give a little…especially with existing conditions
One way of reducing redesigns and construction conflicts during renovation projects is to build more flexibility into the original design. Complete field condition surveys are not often possible at the beginning of a renovation project, when the original building may still be occupied or finishes are still in place. Despite our best assumptions, existing steel framing may not align from floor to floor as precisely as expected, and walls may not be completely plumb or square. Having sufficient additional flexibility in the layouts can make the difference between a quickly resolved RFI with no impact and costly change orders or compromised layouts.
Jarret Johnson, P.E. is an Associate Principal for DeSimone Consulting Engineers. He is currently located in the firm’s Boston, MA office.
Interested in 10 Things Structural Engineers Need to Know from Architects? Check out the blog post by Pascale Sablan, Associate at FXFOWLE Architects.