redundancy factor seismic design

Romanowski29172 May 13, 2022 design , factor , redundancy , seismic Comment

Keywords structural redundancy redundancy factor seismic codes rein-. Redundancy is achieved in a rack system when there is more than one way to withstand the seismic forces.

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

8 Vertical Seismic Load Effect E v.

. Of redundancy over the structural strength through the input kinetic energy of seismic excitation. 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. 7 Redundancy Rho Rho is a factor that penalizes structures that do not have redundancy.

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. Design by using a redundancy factor as proposed and done in some international building codes. Page 4 of 10.

Rho is equal to 10 for SDC B and C for drift calculations non-structural component forces collectors Ω o load combinations and diaphragms. 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.

The Redundancy Factor Rho is a function of the shear taken by a given member and the ground floor area of the building. Wang and Wen 2000 studied a 3-D building model under seismic loadings. 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.

Therefore for such buildings apparent redundant plan configurations are also punished in the design. 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. The effective reduction factor would be.

They proposed a uniform-risk redundancy factor to calculate the required design base-shear force for structures of. Select the seismic force-resisting system based on the seismic design category including requirements for system limitations height limits combinations of framing systems dual. Rho is equal to either 10 or 13.

Song and Wen 2000. Draft redundancy factor which varies as a function of the number of the vertical lines. Two interpretations exist for evaluation of the strength of the system with elements removed.

Examine system for configuration irregularities 10Determine diaphragm flexibility flexible semi-rigid rigid 11Determine redundancy factor ρ 12Determine lateral force analysis procedure 13Compute lateral loads. 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. Determine effective seismic weight.

The first is based on elastic analysis and the second is based on inelastic analysis. 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.

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. Instructional Material Complementing FEMA 451 Design Examples Seismic Load Analysis 9 - 4 Load Analysis Procedure Continued 9. The foundation design would include both the SLRS foundation itself as well as the soil bearing pressure check.

This will be the design seismic force over the entire length of the diaphragm for the direction of interest. W s VL 36000 lbs 130 ft 277 plf. Redundancy Factor ρ Condition 1.

When there is no redundancy the seismic forces must be increased by 30. 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. In ASCE 7 it is a factor applied to seismic loads when certain low-redundancy conditions are met.

For structures assigned to SDC D E and F ρ13 unless one of the following two conditions is met then ρ10 12342. Requires Calculations Redundancy Factor ρ ASCE 7-16 12342 ρ 10 or 13 ρ 13 unless ONE of the following conditions is met. 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.

1234 using Chart 17. 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. Select a permitted structural analysis procedure Sec.

Based upon very simple calculations they preliminary proposed draft values for a redundancy factor which were not intended for implementation in seismic codes or guidelines but to stimulate discussion among design professionals and researchers and to promote research and study. Use of an importance factor greater than one is intended to provide for a lower inelastic demand on a. A First determine the design seismic force for the direction of interest by dividing the base shear by the length of the side of the diaphragm facing the direction of interest.

The Redundancy Factor is a factor intended to penalize structures with little redundancy lack of multiple load paths in their lateral force-resisting systems. The redundancy-energy index ren is defined as follows. Nevertheless the code committee for MOC is considering establishing in the next version that for buildings with strong irregularity condition 10.

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. 1 Each story resisting more than 35 of the base shear in the direction of interest. Rules and exceptions are.

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. The importance factor for seismic I e is based upon Risk Category and the associated Life Safety Hazard and Essential nature of the structure. Assign redundancy factor ρ per Sec.

ASCE7-10 12341 does not explicitly note foundations as an exception where rho 10 and the ASD load. 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. Redundancy Factors for the Se ismic Design of Ductile Reinforced Concrete Chevron Braced Frames 1 INTRODUCTION Although the importance and th e positive effects of structural redundancy have been.

Risa Basic Code Terms For Seismic Behavior And Why We Use Them