redundancy factor seismic design

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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. In ASCE 7 it is a factor applied to seismic loads when certain low-redundancy conditions are met.

Pdf Redundancy Factors For The Seismic Design Of Ductile Reinforced Concrete Chevron Braced Frames

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.

. Response reduction factor R is the factor that should be used to lower the actual base shear in order to obtain the required design lateral force. Seismic Source Type Section 442 5. Seismic Soil Profile Type Section 208431 4.

Seismic Zone Factor Z Section 208441 3. Examine system for configuration irregularities 10Determine diaphragm flexibility flexible semi-rigid rigid 11Determine redundancy factor ρ 12Determine lateral force analysis procedure 13Compute lateral loads. 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.

Structural redundancy redundancy factor seismic codes rein- forced concrete moment frames ductility overstrength. Redundancy Factor ρ Condition 1. The allowable drift limits Δ a for moment frame systems assigned to D E or F seismic design category are divided by the redundancy factor ρ since they are governed by drift considerations per Section 121211 of ASCE 7-16.

The original proposal of UBC-97. Of redundancy over the structural strength through the input kinetic energy of seismic excitation. As a designer I have always applied rho 13 redundancy factor when required for the building per ASCE 7-10 1234 to the SLRS foundation design.

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. The importance factor for seismic I e is based upon Risk Category and the associated Life Safety Hazard and Essential nature of the structure. ASCE7-10 12341 does not explicitly note foundations as an exception where rho 10 and the ASD load.

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. 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. Near Source Factor Section 443 note.

In the case of seismic design of water tanks different values of the R factor are suggested by various countries such as IBC-2000 gives the value of the R factor varying from 2 to 4. Redundancy Factor 33-42 Seismic Load Combinations 43-46. Redundancy is achieved in a rack system when there is more than one way to withstand the seismic forces.

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. Amplification Modal analysis triggers Rho redundancy 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. The foundation design would include both the SLRS foundation itself as well as the soil bearing pressure check.

For structures assigned to SDC D E and F ρ13 unless one of the following two conditions is met then ρ10 12342. 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. 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.

Requires Calculations Redundancy Factor ρ ASCE 7-16 12342 ρ 10 or 13 ρ 13 unless ONE of the following conditions is met. When there is no redundancy the seismic forces must be increased by 30. 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.

Redundancy Factors for the Seismic Design of Ductile Reinforced Concrete Chevron Braced Frames November 2016 Latin American Journal of Solids and Structures 13112088-2112. 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 redundancy-energy index ren is defined as follows.

Importance Factor I Section 20842 2. 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. TehMightyEngineer Structural 15 Jan 15 1649.

For building design I e 10 125 or 15 but for non-structural components Chapter 13 I p 10 or 15 depending on Risk Category SDC component function weight and location. In this sense the RPA992003 recommends that each floor should have a minimum of 3 frames making 2 bays in each direction of a building. Use of an importance factor greater than one is intended to provide for a lower inelastic demand on a.

Most of the seismic design codes require a multiple number of bays. 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. Up to 10 cash back Redundancy factor RR.

The largest value of the Near Source Factor considering all sources shall be use for the design. Assessment of Redundancy Factors for the Seism ic Design. The assessment of the redundancy factor currently proposed in MOC-2008 code MOC-2008 2009 Tena-Colunga et al.

A classification assigned to a structure based on its Risk Category and the severity of the design earthquake ground motion at the site as defined in. Instructional Material Complementing FEMA 451 Design Examples Seismic Load Analysis 9 - 4 Load Analysis Procedure Continued 9. 1 Each story resisting more than 35 of the base shear in the direction of interest.

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.

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