Why Do Some Buildings go up so Fast?

Have you ever passed by a construction site and thought, “Wow, that building really went up fast?” As technology advances and construction and design teams become more sophisticated, we are capable of building structures more efficiently than ever before. But technology is secondary to a highly detailed work plan.  A high level of design documentation with clear and concise details and dimensions allows the construction side to understand even the most complex construction methods.  Speed of construction is directly related to this level of documentation.

Structure is first.

The first part of a building to be constructed, once the site is prepared, is the foundations and superstructure.  Foundations are the footings or piles or any number of other foundation systems common in today’s building structures.  This is followed by the superstructure that supports the building from the foundations up.  At this early stage, the structural engineer is typically first out of the gate, completing their design before the rest of the design team.  The structural engineer must anticipate potential problems the remainder of the design team may encounter as they complete their work.  Lack of understanding of the critical areas of coordination with the architect, mechanical engineer and others on the team will result in changes to the structure late in the process when cost is at the highest level – the dreaded change order!

The higher the quality of documentation, the faster the project is built and the lower the construction cost.

1601 Vine Street in Philadelphia

The more complete the structural engineer’s documents are, the faster the project moves.  As the process begins in earnest, the various structural subcontractors begin to layout their work and develop shop drawings.  Each missing piece of information, missing dimension or unclear or omitted detail causes a request for information (RFI).  Each RFI presents a risk for change orders and delays.  For legal liability reasons, the process has become very cumbersome.  Each question must pass through a “whisper down the lane” procedure that only exacerbates the risk.  The sub sends the RFI to the construction manager who documents and logs the RFI, then sends it to the architect, who documents and logs the RFI and sends it to the structural engineer.  The engineer then logs the RFI and finally begins to answer the question.  Once answered, the reverse process occurs.  If the answer is not well received, the entire cycle begins again.

How does one minimize RFIs?  Well thought out, detailed and accurate structural documents that generate fewer if any RFIs speed up the process.  If the subcontractors can easily interpret the information, there is no need for an RFI.  Each RFI eliminated avoids potential change orders, increased costs and possible delays in the project.

High quality documents also speed up the shop drawings process.  If the structural documents are clear and accurate, the subcontractors can avoid errors in interpretation as they create their respective shop drawings.  That means the structural engineer will likely receive accurate and responsive shop drawings to review and approve in one cycle.  As with RFIs, the shop drawing process follows the same “whisper down the lane” procedure.  Each cycle, each mark on the shop drawing by the structural engineer, represents a potential delay and/or change order.  Often the corrections required on shop drawings rejected by the structural engineer are not because the contractor is inexperienced or careless.  It is due to an honest misinterpretation of an unclear detail or dimension on a poorly executed document.

The structural documentation has a direct impact on a third area of the design and construction process.  The inspectors monitor the construction to confirm that the structure is being completed in conformance with the contract documents and more specifically the structural documents.  They must be able to interpret those documents.  Once again, poorly executed structural documents create a risk of an erroneous interpretation of the design and improperly constructed buildings.  The errors often manifest themselves during construction when a crack in concrete or minor failure occurs and the repair of those problems are extremely expensive and often delay the project.  The most catastrophic result is a failure that can potentially result in injury or death.

High quality documentation results in fewer RFIs, an efficient shop drawing process and fewer construction errors.  Fewer RFIs and an efficient shop drawing process results in fewer change orders and delays to the project.  Fewer errors in construction results in avoidance of costly repairs and delays.  Change orders increase cost.  Repairs increase cost. Delays increase cost.  High quality documentation minimizes these costs and results in a lower final cost for the project.  The project goes up fast!

Complexity increases cost and schedule.

Today’s architecture is more creative, innovative and interesting than ever before.  Buildings are taller, more complex and more unique.  Why is this happening?  Because the power of the technology to analyze these complex structures has been placed on a laptop or desk top computer, readily available to every engineer.  The days of the young engineer spending hours designing individual members, executing the grunt work of design, has been replaced by a computer.  The problem is that the computational portion of structural design represents less than half of the effort.  The real challenge for the structural engineer is to address the complexities of the structure and its behavior through elegant solutions.  The optimum structure provides the simplest solution possible to an otherwise complex situation.  This requires experience and creativity. The computer will not give the engineer this answer.  It takes an in-depth understanding of the structural behavior, the ability to visualize alternatives, and solutions.  Shooting from the hip results in costly results.  Complex, first iteration solutions cause extended project schedules.

The optimum solution requires a deep understanding of how the structure will be built in a geographic market.  New York is different than Washington, DC.  Philadelphia is different than Los Angeles.   A team effort that draws on the expertise of the construction side, through cooperation and communication, allows the solution to rise to the top.  Senior level involvement in each project imparts the practical experience and lessons learned from previous projects to the solution for the next.  Experience allows the design team to anticipate areas susceptible to challenges and preemptively document solutions.

Return on investment

The structural engineering fee for the average building project is less than 0.4% of the overall construction cost.  On average, the cost of constructing the structure for that building is about 20% of the total construction cost.  Detailed documentation and highly experienced expertise can easily result in a 10% savings in the structural construction cost.  This results in a savings of 2% on overall construction cost.  Even a large 30% difference in structural engineering fee, (0.12% of construction cost,) resulting in this 2% cost reduction in construction can realize savings of 17 times the investment in added structural engineering fee.  A 1,700% return on investment!

Why do some buildings go up so fast?  Because a wise owner has invested in structural engineering services that include careful study of alternatives, experienced engineers and detailed and fully dimensioned documents.  RFIs are reduced if not eliminated and construction flows smoothly.  This combined with an experienced top level construction team, is why some buildings go up so fast.

By Kirk Harman