Wind loads and NCh432. Importance in structural design and calculation
Climate change is not only changing our weather patterns, it is also intensifying extreme weather events, such as winds. This increase in the speed and frequency of strong winds poses a growing threat to the safety of our buildings.
Gusts of up to 79mph were recorded in the Metropolitan Region in August 2024. Location: Panamericana Norte, Santiago. Photograph: Ingek
Wind, an increasingly relevant dynamic load
Wind, as a dynamic load, exerts varying forces on structures. These forces can cause oscillations, vibrations, and in extreme cases, collapse. With increasing wind intensity due to severe weather events, these loads become more significant and must be considered more accurately in structural design.
The Chilean Standard NCh432: Our compass in the calculation of constructions
In Chile, the NCh432:2010 standard "Structural design - Wind loads" establishes the criteria and procedures for determining the wind loads that must be considered in the design of structures. This standard is a fundamental tool to guarantee the safety of our buildings against the effects of the wind.
An obvious and necessary question would be: Should we, as structural engineers, rethink and update the current regulations in light of the new challenges imposed by climate change in Chile?
Why is the NCh432 standard so important?
Calibration of designs: The standard provides the methods and parameters necessary to calculate wind pressures based on geographic location, terrain topography, and height of the structure, among others.
Consideration of dynamic effects: NCh432 includes provisions for the dynamic analysis of structures, allowing the evaluation of the response of buildings to wind gusts and based on the type of structures.
Procedures: The standard establishes procedures for the calculation of structures, such as: simplified procedure, analytical procedure, and wind tunnel procedure.
The implications of climate change on structural design
Increasing wind intensity requires a review of the design criteria established in NCh432. Structural engineers must remain aware of updates to the standard and the latest research in the field of building aerodynamics.
Sign damaged by strong gusts of wind. Location: Quilicura. Photography: Ingek
Some of the measures that can be adopted to ensure the resistance of structures to wind are:
More detailed analysis: Conduct more accurate structural analysis, taking into account the spatial and temporal variability of wind loads.
Design of resistant elements: Use materials and construction systems capable of resisting the forces generated by the wind, such as reinforced connections and structural configurations designed to adequately resist eventual loads.
Consideration of secondary effects: Evaluate the secondary effects of wind, such as increased internal pressure, suction effects on roofs, and vibration of non-structural elements.
Design of ventilated facades: Implement ventilated facade systems that reduce wind pressure on buildings.
Wind loads caused the sign to tip over. Location: Quilicura. Photography: Ingek
Conclusion
Climate change is changing the environmental conditions to which our buildings are subjected. Increasing wind intensity represents a new challenge for structural engineering. By following the recommendations of the NCh432 standard and adopting appropriate design measures, we can ensure the safety of our buildings and adapt to the changes that are coming.
It is essential that structural engineers, designers and competent authorities work together to face this challenge and build a safer and more resilient future.
What measures do you think should be taken to improve the safety of buildings in the face of increasing winds?
#climatechange, #wind, #structuralengineering, #NCh432, #earthquakeresistantdesign, #constructionsafety #structuralengineer.
Note: This text is a general guide and is not a substitute for the advice of a structural engineering professional.
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