Using conditional mean spectra and uniform hazard spectra for seismic analysis of bridges

2021 ◽  
pp. 1-21
Author(s):  
Dirk Proske ◽  
T. Walti ◽  
D. Kurmann ◽  
Philippe Renault
Keyword(s):  
Seismic Analysis ◽  
Uniform Hazard Spectra ◽  
Conditional Mean

Direct generation of floor design spectra (FDS) from uniform hazard spectra (UHS) — Part I: formulation of the method

2020 ◽  
Vol 47 (12) ◽  
pp. 1372-1386 ◽  
Author(s):  
Amin Asgarian ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Three Dimensional ◽  
Response Spectra ◽  
Ambient Vibration ◽  
Uniform Hazard Spectra ◽  
Design Spectra ◽  
Floor Response Spectra ◽  
Response Amplification ◽  
Direct Generation ◽  
Ambient Vibration Measurements

In most current building codes, seismic design of non-structural components (NSCs) is addressed through empirical equations that do not capture NSC response amplification due to tuning effects with higher and torsional modes of buildings and that neglect NSC damping. This work addresses these shortcomings and proposes a practical approach to generate acceleration NSC floor design spectra (FDS) in buildings directly from their corresponding uniform hazard spectra (UHS). The study is based on the linear seismic analysis of 27 reinforced concrete buildings located in Montréal, Canada, for which ambient vibration measurements (AVM) are used to determine their in situ three-dimensional dynamic characteristics. Pseudo acceleration floor response spectra (PA-FRS) are derived at every building floor for four different NSCs damping ratios. The calculated roof FRS are compared with the 5% damped UHS and a formulation is proposed to generate roof FDS for NSCs with 5% damping directly from the UHS.

Conditional Mean Spectra Given a Vector of Spectral Accelerations at Multiple Periods

2017 ◽  
Vol 33 (2) ◽  
pp. 469-479 ◽  
Author(s):  
Tadahiro Kishida
Keyword(s):  
Ground Motion ◽  
Uniform Hazard Spectra ◽  
Mathematical Formula ◽  
Conditional Mean ◽  
Design Spectra ◽  
Design Practices ◽  
Design Requirements ◽  
Spectral Accelerations ◽  
Pseudo Spectral

Conditional mean spectra (CMS) are generally defined as expected pseudo-spectral accelerations (PSA) conditioned on uniform hazard spectra (UHS) at a selected period. Many design practices prefer CMS because UHS conservatively envelop the large amplitudes of PSA within a single ground motion. However, in some situations, CMS are preferred given target spectra from UHS at multiple periods (CMSV) for satisfying design requirements. This study presents the mathematical formula of CMSV and describes the methodology to compute CMSV with application examples. The presented method for computing CMSV can provide the transitional design spectra between currently used CMS and UHS depending on the selected conditioning periods.

Vergleich seismischer Schnittgrößen aus CMS und UHS für vier Schweizer Bestandsbrücken/Comparison of seismic internal forces from CMS and UHS for four Swiss bridges

Bauingenieur ◽  
2021 ◽  
Vol 96 (07-08) ◽  
pp. 266-274
Author(s):  
Thomas Walti ◽  
Dirk Proske ◽  
Kevin Schaffner ◽  
Marcel Imhof ◽  
Robert Wagner ◽  
...  
Keyword(s):  
Uniform Hazard Spectra ◽  
Conditional Mean ◽  
Internal Forces

In diesem Beitrag werden die seismischen Schnittgrößen von vier Schweizer Bestandsbrücken mit den Verfahren der Conditional Mean Spectra (CMS) und der Uniform Hazard Spectra (UHS) berechnet und verglichen. Bei den Brücken handelt es sich um zwei Stahlbeton- und zwei Stahlbrücken, von denen jeweils eine für den Straßen- und eine für den Eisenbahnverkehr genutzt wird. Durch die Brückenauswahl soll die Gültigkeit der Untersuchungsergebnisse für die gewählten Brückentypen und Nutzungszwecke gezeigt werden. Im Mittel zeigen die Berechnungen bei Anwendung CMS geringere Schnittgrößen als bei Anwendung UHS. Die Differenz ist jedoch geringer als basierend auf der Literatur und auf eigenen Voruntersuchungen zu erwarten war. Dazu kommt, dass die praktische Anwendung im Ingenieurbüro mit den heutigen Softwarelösungen sehr aufwendig ist. Prinzipiell zeigen die Berechnungen aber auch, dass die Differenzen auf Bauteilebene signifikant sein können und dass programmtechnische Verbesserungen die Anwendung in der Praxis erlauben würden.

SEISMIC ANALYSIS OF MULTISTOREY REINFORCED CONCRETE STRUCTURES

2019 ◽  
Vol 9 (1) ◽  
pp. 61
Author(s):  
SINGH RAVIKANT ◽  
KUMAR SINGH VINAY ◽  
YADAV MAHESH ◽  
◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Seismic Analysis ◽  
Concrete Structures ◽  
Reinforced Concrete Structures

Comparison of Interstorey Drift in General RC Buildings in Pounding and No Pounding Case

2020 ◽  
Vol 2 (1) ◽  
pp. 40-47
Author(s):  
Anand Dev Bhatt
Keyword(s):  
Seismic Analysis ◽  
Linear Time ◽  
Time History ◽  
Case Analysis ◽  
Rc Buildings ◽  
Adjacent Buildings ◽  
Sufficient Distance ◽  
Earthquake Load ◽  
Interstorey Drift ◽  
Lower Height

 Inter-storey drift is an important parameter of structural behavior in seismic analysis of buildings. Pounding effect in building simply means collision between adjacent buildings due to earthquake load caused by out of phase vibration of adjacent buildings. There is variation in inter-storey drift of adjacent buildings during pounding case and no pounding case. The main objective of this research was to compare the inter-storey drift of general adjacent RC buildings in pounding and no pounding case. For this study two adjacent RC buildings having same number of stories have been considered. For pounding case analysis there is no gap in between adjacent buildings and for no pounding case analysis there is sufficient distance between adjacent buildings. The model consists of adjacent buildings having 4 and 4 stories but unequal storey height. Both the buildings have same material & sectional properties. Fast non-linear time history analysis was performed by using El-centro earthquake data as ground motion. Adjacent buildings having different overall height were modelled in SAP 2000 v 15 using gap element for pounding case. Finally, analysis was done and inter-storey drift was compared. It was found that in higher building inter-storey drift is greater in no pounding case than in pounding case but in adjacent lower height building the result was reversed. Additionally, it was found that in general residential RC buildings maximum inter-storey drift occurs in 2nd floor.

SEISMIC VULNERABILITY ASSESSMENT FOR SAN FRANCISCO TEMPLE IN MORELIA, MEXICO

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 207-2016
Author(s):  
Guillermo Martinez ◽  
David Castillo ◽  
José Jara ◽  
Bertha Olmos
Keyword(s):  
San Francisco ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Middle Part ◽  
Seismic Demands ◽  
Modeling And Analysis ◽  
Seismic Records ◽  
Cracking Pattern ◽  
The Temple

This paper presents a first approximation of the seismic vulnerability of a sixteenth century building which is part of the historical center of Morelia, Mexico. The city was declared World Heritage by United Nations Educational, Scientific and Cultural Organization in 1991. The modeling and analysis of the building was carried out using a three-dimensional elastic tetrahedral finite elements model which was subjected to probabilistic seismic demands with recurrences of 500 yrs and 1000 yrs in addition to real seismic records. The model was able to correctly identify cracking pattern in different parts of the temple due to gravitational forces. High seismic vulnerability of the arched window and the walls of the middle part of the bell tower of the temple was indicated by the seismic analysis of the model.

A SIMPLIFIED ANALYTICAL PROCEDURE FOR SEISMIC ANALYSIS OF TIMBER LIGHT-FRAME SHEAR WALLS

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 173-180
Author(s):  
Giorgia Di Gangi ◽  
Giorgio Monti ◽  
Giuseppe Quaranta ◽  
Marco Vailati ◽  
Cristoforo Demartino
Keyword(s):  
Analytical Procedure ◽  
Seismic Analysis ◽  
Shear Walls ◽  
Element Model ◽  
Sensitivity Analyses ◽  
Width Ratio ◽  
Damping Factor ◽  
Equivalent Viscous Damping ◽  
Design Variables ◽  
Depth Analysis

The seismic performance of timber light-frame shear walls is investigated in this paper with a focus on energy dissipation and ductility ensured by sheathing-to-framing connections. An original parametric finite element model has been developed in order to perform sensitivity analyses. The model considers the design variables affecting the racking load-carrying capacity of the wall. These variables include aspect ratio (height-to-width ratio), fastener spacing, number of vertical studs and framing elements cross-section size. A failure criterion has been defined based on the observation of both the global behaviour of the wall and local behaviour of fasteners in order to identify the ultimate displacement of the wall. The equivalent viscous damping has been numerically assessed by estimating the damping factor which is in use in the capacity spectrum method. Finally, an in-depth analysis of the results obtained from the sensitivity analyses led to the development of a simplified analytical procedure which is able to predict the capacity curve of a timber light-frame shear wall.

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