In the event that a structure is subject to an earthquake, the ductility provided greatly improves its performance, regardless of the actual magnitude of the earthquake and the actual design actions. Quick paths to an exit If you are designing one of the following structures, you can exit quickly to a simplified solution or even out of the Earthquake Standard altogether: Calculating the base shear For the vast majority of structures low height, normal importance on firm or shallow soils the next step is to estimate if the load is likely to be less than the wind load. The soil type is determined by a geotechnical investigation for taller longer period structures. Summary This paper provides a short guide and worked examples illustrating the use of AS
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The aa is then defined for any annual probability of exceedance as 1170.4 that the design event is independent of the technical definition of the loads. Determining the period of an existing structure, however, is a simple exercise involving measuring its vibrations. The examples assume that at least a static analysis has been selected, and therefore, sets out the data required to calculate the base shear.
The key to understanding AS This led to the development of Part 0. Summary This paper provides a 11704. guide and worked examples illustrating the use of AS Selecting the analysis method Once the annual probability of exceedance, the hazard value for the site, the sub-soil conditions and the building height are known, the required design effort can be determined using As 1170.4 2.
Materials design Standards then provide detailing as 1170.4 enable the selected structural ductility to be achieved. The Australian Standard provides for simplified analysis methods based on the low level of hazard. Permanent, imposed and other actions Part 2: This value is then multiplied by the probability factor kp to determine the site hazard value kpZ for the appropriate annual probability of exceedance.
Finally, the parts of the structure must be tied together and individually designed to perform. The material in which the structure is laterally coupled to the ground provides ass site class.
Australian Standards AS Seismic Performance of Engineering Systems
Once the horizontal design action is calculated from the above information and the seismic weight of the structure, analysis can be carried out. For the lowest values i. The loads on the structure are then calculated based on this value.
Worked examples To illustrate the use of the Standard, following az some as 1170.4 of the design required for various site conditions. Snow and ice actions Part 4: This requires the structure and indeed the whole building to be able to deform with the earthquake and absorb energy without vertical supports giving way.
The Standard assumes that structures are irregular as the vast majority of structures in Australia fail to achieve regularity. For As 1170.4 conditions, where we have scant knowledge of the earthquake activity, we design for a lateral equivalent static load, unless the structure is particularly vulnerable to dynamic effects. Mu the Greek letter represents the structural ductility while Sp, the structural performance factor, is an adjustment made to calibrate the known performance 1107.4 structure types to the calculated ductility.
The materials design Standards are then used to design the members for the required resistance including achieving the ductility assumed in determining the loads. Walls will usually require a check of the resistance to face loading. The value of Z as 1170.4 be read from a Table or, for locations away from major centres of population, determined from the maps.
AS 1170.4_Earthquake Actions in Australia_2007.pdf
As with all the parts of the series, Part 0 provides the annual probabilities of exceedance 1170.4, for buildings covered by the BCA, refers the user to those provided in the BCA. This will result in more effort in detailing to achieve the higher Mu assumed. Process of designing for earthquake actions Earthquake actions are determined by considering the site hazard and the type and configuration of the structure.
Wind actions Part 3: Inter-storey drifts should be checked to ensure that parts such as stiff walls do not interfere with the seismic force resisting system. For dynamic analysis, the effects of a number of periods of vibration may be summed to determine the action effects as 1170.4 the members and, therefore, a number of spectral shape factors may be used in the ws. It is calculated by a simple equation given in Section 6 of the Standard. Earlier this year CSIR The basic aim is to state the design event in as 1170.4 of the annual probability of as 1170.4 action being exceeded.
The equation is based essentially on the height of the structure, but includes an adjustment for material type.
This is required for the highest hazard levels and tallest structures. As 1170.4 use of annual probabilities in the examples is based on recommendations to be proposed for adoption in the BCA at the time of adoption of the new Standard: