You don’t want to wait until the Big Bag Wolf comes along to huff and puff to determine your building’s structural integrity. Long before he arrives, you should have a thorough structural analysis completed by a structural engineer who looks at a variety of factors.
Considerations in a Structural Analysis
Dead and live loads will need to be supported by the design of any structure. Everything from a building’s foundation, walls, and roof to a bridge’s ability to withstand traffic and snow loads, needs to be sufficiently designed to ebb and flow with the elements.
What is Analyzed
Structural engineers need to investigate specific design elements, including the building’s geometry, support conditions, materials used, and structural load it will bear. The result of the analysis should report on how the structure will react based on its current design, and what stresses it will be subject to.
If you really think about it, even finished structures with the most well-thought-out earthquake-resistant designs are still prototypes until they actually encounter a quake. All the analysis in the world cannot determine with 100% accuracy how a building will look after the ground under it moves. Structural engineers can only do their best with the data they have to make a prediction.
Types of Load Considerations
A structure’s intended use will influence some of the load considerations made in a structural analysis. In addition to the dead and live loads mentioned above, engineers also look at super-imposed dead load, which includes the weight contributed by flooring and wall partition materials. There are different requirements for load considerations, which are influenced by not just what the building is used for, but how tall it is going to be.
A structural analysis needs to determine how a building will respond to dynamic elements such as people, traffic, routine weather, and earthquakes. Any force that can act upon a structure should be considered, and its effects can be determined manually or via finite element analysis. To counteract any energy force, a building mainly uses friction to dissipate it. Dampening can be achieved with the use of certain materials, including bolted steel, reinforced concrete, welded steel, and brick masonry. Often, rubber is added to any of these materials to absorb vibrations.
Stability and Buckling
Structural engineers must determine how a building will withstand sudden changes in shape. While buckling under changes of force may be inevitable, a building can be designed to do so in safe ways. Good design can help distribute force so if one element of a structure buckles, folds, or topples, the rest of the building won’t be as susceptible to tumbling like dominoes as well.
Mechanics or Strength of Materials
It’s said that a chain is only as strong as its weakest link, and the same principle applies to buildings. Strength of materials plays an important role in how a structure stands up to outside forces big and small.
Materials used are often determined by climate, cost, and convenience. Ideally, all three factors would align and builders would have easy access to affordable materials that are the best for the job. Whatever materials are proposed for a structure must be tested for their tolerance of plain loads, like torsion and axial loading. It needs to be determined under what circumstances materials could deteriorate, and if any improvements to a material’s strength could change its integrity.
CODES TO CONSIDER
Building codes vary by region, but there are national organizations with which a structural design must comply.
- American Concrete Institute (ACI)
- American Wood Council (AWC)
- American Institute of Steel Construction (AISC)
- American Iron and Steel Institute (AISI)
- American Society of Civil Engineers (ASCE)
- American Welding Society (AWS)
- Department of Defense (DoD)
- International Code Council (ICC)
- Metal Building Manufacturers Association (MBMA)
- National Fire Protection Association (NFPA)
- Steel Deck Institute (SDI)
- Steel Joint Institute (SJI)
The codes that are applicable to the type of structure, how it’s used, and where it’s located will affect how a building is framed, right down to the thickness of each concrete slab poured, and the dimensions of roof beams. Getting permits approved from each organization will affect the building timeline and budget, so it’s important to always be one step ahead of the game and to know what is required from which entity prior to forging ahead.
Whether the structure is a bridge, a building, or a tower, a thorough structural analysis should be able to predict how it will react to external loads. A structure should not only be serviceable, but safe as well.
For a more comprehensive understanding of the structural analysis process, as well as the surveys involved in how a building may affect the environment, get in touch with Anderson Engineering today. We provide customized solutions for any project.