Hind Hammada: Why does the ACSE code require scaling dynamic forces for seismic design, and what is the specific scaling factor? Almost all dynamic analysis results are less than of static ones (such as ELF). So the values like Base Shear tend to be smaller in dynamic analysis than ELF results. In ASCE7 you scale up to 100% ELF so you get little bump if things go your way. I agree in principle, though, that the choice to go RSA/NLA is usually driven more by having identified the need to capture complex dynamic behavior than by a desire to save on construction costs. ASCE 7-22 12.9.1.4 #RekanDaho
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First of all, we have to know that we have two different scaling; the scaling of forces and the scaling of drifts, so the MRSA forces used to design the elements may be differ from forces used to check drift (as I said; may be) The scaling of forces starts from initial scaling ( gI/R) to take the effect of importance factor and response modification factor , then we have to do scaling up 100% of ELF (scaling down is not permitted) because the computed fundamental period may be the result of an overly flexible (incorrect) analytical model (In other words; flexible building may results in very low base shear). Scaling of Drifts Displacements from the modal response spectrum are only scaled to the ELF base shear where Vt is less than CsW and Cs is determined based on Equation (12.8-7). For all other situations, the displacements need not be scaled, because the use of an overly flexible model will result in conservative estimates of displacement that need not be further scaled. So finally we have; ELF (Forces) for strength design ELF (Forces) for drift check MRSA (Forces) for strength design MRSA (Forces) for drift check
Hind Hammada: Why does the ACSE code require scaling dynamic forces for seismic design, and what is the specific scaling factor? Almost all dynamic analysis results are less than of static ones (such as ELF). So the values like Base Shear tend to be smaller in dynamic analysis than ELF results. In ASCE7 you scale up to 100% ELF so you get little bump if things go your way. I agree in principle, though, that the choice to go RSA/NLA is usually driven more by having identified the need to capture complex dynamic behavior than by a desire to save on construction costs. ASCE 7-22 12.9.1.4 #RekanDaho
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I have arranged the ideas in very professional way to improve the understanding of the seismic design provisions of ASCE7-22
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Attention seismic specialists! 🚨 Did you know? ASCE 7-16 2.4.5 outlines seismic load effects under section 12.4.3, including overstrength. When applying this section, a minimum omega value of 2.5 for light-frame wood walls (per table 12.2-1 note b), may be reduced to 2.08 (2.5/1.2) per 2.4.5. your thoughts. #SeismicEngineering #ASCE #StructuralEngineering
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Background to Some of the Seismic Design Provisions of the 2015 NBCC
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Here is the result of hardwork and teamwork.... 🎉 Successfully completed the 8th semester project on Analysis and Design of G+4 RCC Building ( for seismic zone V)
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Learn how to evaluate seismic performance using Pushover Analysis based on FEMA and Eurocode 8 standards. https://hubs.ly/Q02YtQ6Y0 Enjoy a 30-minute advanced video lecture and access detailed PPT document. Explore even more specialized content – visit now and elevate your expertise! #civilengineering #civilengineer #structuralengineering #structuralengineer #motivewith #midasit #structuraldesign
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FAQ: What is the Max Stress Check result in DeepFND? Ever wondered what the Max Stress Check in the summary table of DeepFND means? It’s your go-to indicator for identifying the most critical structural or geotechnical check during analysis! #DeepExcavation #DeepFND #FoundationDesign #StructuralEngineering #GeotechnicalEngineering #DeepExcavation
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Do I need to use AISC 341 if my Seismic Design Category is B and the R value is greater than ( 3)?
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Understanding Mass Source in ETABS for Seismic analysis When it comes to seismic analysis, defining the Mass Source in ETABS is crucial! As the name suggests, it refers to the mass of the structure, including its self-weight and any additional mass due to surface loads or line loads, typically considering both Dead Load (DL) and Live Load (LL). Why is Mass Source Important? Mass Source is essential for calculating the base shear ofa structure, a key factor in seismic design. 7I IS 1893:2016 Guidelines: As per Clause 7.3.1, for seismic design, we consider full dead load plus a percentage of the imposed load: 25% of LL when the intensity is up to 3.0kN/m2 50% of LL when it exceeds 3.0kN/m2 Accurately defining the Mass Source ensures that your seismic analysis is reliable and adheres to the latest standards.
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Seismic isolators are crucial for ensuring structural stability, resilience, and performance. At #Doshin, we prioritise reliability through precision engineering. Discover us at www.doshinrubber.com #SeismicIsolator #highdampingrubberbearing #leadrubberbearing
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Structural Consultant | Extensive Experience in ACI & ASCE Codes
7moFirst of all, we have to know that we have two different scaling; the scaling of forces and the scaling of drifts, so the MRSA forces used to design the elements may be differ from forces used to check drift (as I said; may be) The scaling of forces starts from initial scaling ( gI/R) to take the effect of importance factor and response modification factor , then we have to do scaling up 100% of ELF (scaling down is not permitted) because the computed fundamental period may be the result of an overly flexible (incorrect) analytical model (In other words; flexible building may results in very low base shear). Scaling of Drifts Displacements from the modal response spectrum are only scaled to the ELF base shear where Vt is less than CsW and Cs is determined based on Equation (12.8-7). For all other situations, the displacements need not be scaled, because the use of an overly flexible model will result in conservative estimates of displacement that need not be further scaled. So finally we have; ELF (Forces) for strength design ELF (Forces) for drift check MRSA (Forces) for strength design MRSA (Forces) for drift check