redundancy factor seismic design

sannon May 29, 2022 factor , redundancy , seismic , wallpaper Comment

Two interpretations exist for evaluation of the strength of the system with elements removed. Why is there a seismic importance factor I e 125 in Table 15-2 but only.

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Factor 07 E for Allowable Stress Design Ev Vertical seismic effect Vertical distribution of base shear Orthogonal effects on corner columns Diaphragm forces Accidental torsion Foundation ties Unique calculations and detailing for Special Steel Systems Concrete detailing and splice lengths when subject to high seismic Wood frame hold-downs Masonry wall anchors and.

. Cortés-Benítez Assessment of Redundancy Design Factors Latin American Journal of Solids and Structures 12 2015 2330-2350 mands for beams and columns. U en y E r E 2 where Eu is the total seismic energy for the lifespan of the structure until collapse and Ey is the seismic energy up to the first yielding. The seismic importance factor Ie is used in the Seismic Response Coefficient CS equations with the intent to raise the yield level for important structures eg hospitals fire stations emergency operation centers hazardous facilities etc.

Requires Calculations Redundancy Factor ρ ASCE 7-16 12342 ρ 10 or 13 ρ 13 unless ONE of the following conditions is met. As observed according to ASCE-7 the redundancy factor is taken into consideration to amplify or diminish seismic lateral forces based upon the seismic design category which is a classification assigned to a structure based on its occupancy and the severity of the design earthquake ground motion at the site as described in detail in sections 116 117. Redundancy is achieved in a rack system when there is more than one way to withstand the seismic forces.

In addition to evaluating the governing Rho factor for the whole structure for each of the seismic load cases the program also calculates and outputs the Rho factor for each column brace and wall element in the structure for all seismic load cases. For structures in Seismic Design Categories SDCs D E and F the redundancy factor is 13 but may be reduced to 10 if it passes either a configuration test or a calculation test. Redundancy Factor ρ Condition 1.

The original proposal of UBC-97. The down-aisle direction of an industrial storage rack system is already comprised of semi-rigid beam-to-column connections as well as base plates securely anchored to the floor. In order to ensure reliability many requirements are triggered with each R factor.

They proposed a uniform-risk redundancy factor to calculate the required design base-shear force for structures of. When there is no redundancy the seismic forces must be increased by 30. Use of an importance factor greater than one is intended to provide for a lower inelastic demand on a.

For structures with low inherent redundancy the required design forces are amplified by 30 to increase strength and resistance to damage. Instructional Material Complementing FEMA 451 Design Examples Seismic Load Analysis 9 - 4 Load Analysis Procedure Continued 9. The results obtained in these analyses lead to the conclusion that although redundancy can result in several beneficial effects on the earthquake response a component of the reduction factor R due to redundancy R R as suggested in recent publications cannot be established independently of the over-strength and ductility of the structural.

Tena-Colunga Redundancy Factors for the Seismic Design of Ductile Reinforced Concrete Chevron B r aced Fr ames 2103 Latin American Journal of Solids and. TehMightyEngineer Structural 15 Jan 15 1649. Also known as the reliability factor the redundancy factor ρ introduces a multiplier to increase thedesign horizontal force being considered for a structural element.

As observed according to ASCE-7 the redundancy factor is taken into consideration to amplify or diminish seismic lateral forces based upon the seismic design category which is a classification assigned to a structure based on its occupancy and the severity of the design earthquake ground motion at the site as described in detail in sections 116 117 and 118 of ASCE-7 2010 ASCE. In ASCE-7 2013 the redundancy factor ρ is taken into consideration at the time of assessing the horizontal seismic load effect E h as. For structures assigned to SDC D E and F ρ13 unless one of the following two conditions is met then ρ10 12342.

The response modification coefficient R is part of a concept where an elastic design may be performed but with due consideration of the overstrength and ductility inherent in the lateral force resisting system. ACI 318-11 Appendix D actually revised this requirement in two ways to make it align with the ASCE 7-10 seismic load combinations with overstrength factor. Examine system for configuration irregularities 10Determine diaphragm flexibility flexible semi-rigid rigid 11Determine redundancy factor ρ 12Determine lateral force analysis procedure 13Compute lateral loads.

The first is based on elastic analysis and the second is based on inelastic analysis. Introduction of the redundancy coefficient into the building code was a direct reaction of the observation of structures damaged by the 1994 Northridge earthquake and the resulting. The assessment of the redundancy factor currently proposed in MOC-2008 code MOC-2008 2009 Tena-Colunga et al.

A state of redundancy in astructural system can be attained by allowing several load path options for the lateral loads actingon the structure. Of redundancy over the structural strength through the input kinetic energy of seismic excitation. Wang and Wen 2000 studied a 3-D building model under seismic loadings.

If a structure is regular in plan and there are at least 2 bays of seismic force resisting perimeter framing on each side of the structure in each. 1 Each story resisting more than 35 of the base shear in the direction of interest. The Redundancy Factor Rho is a function of the shear taken by a given member and the ground floor area of the building.

Building Codes To the authors knowledge the first building code to directly include a redundancy factor for the seismic design of buildings was the 1997 UBC Code UBC-97 1997. Draft redundancy factor which varies as a function of the number of the vertical lines. H E EρQ 1 where Q E is defined as the effects of horizontal seismic forces from V total design lateral force or shear at the base or F p the seismic force acting on a component of a structure.

However when reducing the design strength by a factor of 04 you are essentially applying a 25 overstrength factor on the total demand not just the horizontal seismic effect. The redundancy-energy index ren is defined as follows. In ASCE 7 it is a factor applied to seismic loads when certain low-redundancy conditions are met.

The code was then modified to encourage increased redundancy for structures in Seismic Design Categories D E and F. The intent of the redundancy coefficient is to encourage the design of more redundant structures with a greater number of elements provided to resist lateral forces.

Pdf The Role Of Redundancy And Overstrength In Earthquake Resistant Design Semantic Scholar