BSVBD
Structural
- Jul 23, 2015
- 463
Importance Factors
Wisconsin is still under IBC 2009 & ASCE 7-05.
ASCE 7-05, Table 1-1 assigns Agricultural Facilities, Certain Temporary Facilities and Minor Storage Facilities to Occupancy Category “I”.
ASCE 7-05, Table 6-1 assigns Importance Factors of 0.87 and 0.77 for wind and Table 7-4 an Importance Factor of 0.8 for snow.
In summary, the “GENERAL” (ASCE 7-05 Chapter 1) intent of ASCE 7-05, 1.3 BASIC REQUIREMENTS AND 1.4 GENERAL STRUCTURAL INTEGRITY, (with statements such as, “Buildings and other structures, and all parts thereof, shall be designed and constructed to support safely the factored loads in load combinations defined in this document without exceeding the appropriate strength limit states for the materials of construction.” and “Buildings and other structures shall be designed to sustain local damage with the structural system as a whole remaining stable and not being damaged to an extent disproportionate to the original local damage.”) is, “The structure shall not fall down!!!”
ASCE 7-05, Table 1-1 assigns Agricultural Facilities, Certain Temporary Facilities and Minor Storage Facilities to Occupancy Category “I”.
ASCE 7-05, Table 6-1 assigns an Importance Factor of 0.87 and 0.77 for wind and Table 7-4 an Importance Factor of 0.8 for snow.
Why should we be allowed to reduce the applicable loads on structures that WILL be occupied, at some time, regardless of duration, by people. Conversely, since the general intent of structural engineering standards employs safety and stability, implying that structures classified as Occupancy Category “I” shall be designed to remain stable, why aren’t we allowed to use the lesser (reduced) loads, allowed for Occupancy Category “I” structures, for Occupancy Category “II” structures?
In general, Occupancy Categories III and IV structures DO have necessary safety considerations that should NOT be considered applicable to the aforementioned topical inquiry and conversation applicable to Categories “I & II”.
P.S. During my first review of wood trusses for an AG-structure, while inquiring why we allow such reduced loads on AG buildings that DO contain human beings, the individual replied, “Remember, us “AG” people are not important!”
Wisconsin is still under IBC 2009 & ASCE 7-05.
ASCE 7-05, Table 1-1 assigns Agricultural Facilities, Certain Temporary Facilities and Minor Storage Facilities to Occupancy Category “I”.
ASCE 7-05, Table 6-1 assigns Importance Factors of 0.87 and 0.77 for wind and Table 7-4 an Importance Factor of 0.8 for snow.
In summary, the “GENERAL” (ASCE 7-05 Chapter 1) intent of ASCE 7-05, 1.3 BASIC REQUIREMENTS AND 1.4 GENERAL STRUCTURAL INTEGRITY, (with statements such as, “Buildings and other structures, and all parts thereof, shall be designed and constructed to support safely the factored loads in load combinations defined in this document without exceeding the appropriate strength limit states for the materials of construction.” and “Buildings and other structures shall be designed to sustain local damage with the structural system as a whole remaining stable and not being damaged to an extent disproportionate to the original local damage.”) is, “The structure shall not fall down!!!”
ASCE 7-05, Table 1-1 assigns Agricultural Facilities, Certain Temporary Facilities and Minor Storage Facilities to Occupancy Category “I”.
ASCE 7-05, Table 6-1 assigns an Importance Factor of 0.87 and 0.77 for wind and Table 7-4 an Importance Factor of 0.8 for snow.
Why should we be allowed to reduce the applicable loads on structures that WILL be occupied, at some time, regardless of duration, by people. Conversely, since the general intent of structural engineering standards employs safety and stability, implying that structures classified as Occupancy Category “I” shall be designed to remain stable, why aren’t we allowed to use the lesser (reduced) loads, allowed for Occupancy Category “I” structures, for Occupancy Category “II” structures?
In general, Occupancy Categories III and IV structures DO have necessary safety considerations that should NOT be considered applicable to the aforementioned topical inquiry and conversation applicable to Categories “I & II”.
P.S. During my first review of wood trusses for an AG-structure, while inquiring why we allow such reduced loads on AG buildings that DO contain human beings, the individual replied, “Remember, us “AG” people are not important!”
