AS 1170.4 PDF
February 19, 2020 | by admin
Australian Standard – Commentary. AEES member and past president John Wilson has produced a publication titled “AS Summary This paper provides a short guide and worked examples illustrating the use of AS Structural design actions Part 4. Download AS _Earthquake Actions in Australia_pdf.
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In cases where a static or dynamic analysis is required, the first mode natural period of vibration of the structure is calculated T1. This value is then multiplied by the probability factor kp to determine 110.4 site hazard value kpZ for the appropriate annual probability of exceedance. A similar approach to reducing loads assuming a higher Mu value could be used where Z is high.
Section 6 sets out the method including the spectral shape factor, the structural ductility and performance factors, the natural period of vibration of the structure, etc.
Once the value of Mu is selected the structure must then be detailed to achieve that selected ductility.
This was a group of loading experts from across the APEC region that met to create a means of establishing inter-changeability between the loading codes of 117.04 nations. General principles Part 1: In order to achieve a ductility assumed in design of the structure, it is essential that stiff elements should not impose themselves on the behavior of the seismic force resisting system.
Therefore, it is not expected that a structure subject to the design earthquake would be undamaged, but rather that the damage had not progressed to collapse.
Period of vibration of the structure The construction material, type of structure, and the period of the first mode of vibration all have an influence on the forces experienced by the structure. 1170. actions in Australia. This paper assumes that at least a static analysis has been selected, and therefore, the remaining data required to calculate the base shear has to be determined. The Australian Standard provides for simplified analysis methods based on the low level of hazard.
For dynamic sa, the effects of a number of periods of vibration may be summed to determine the action effects in the members and, therefore, a number of spectral shape factors may be used in the analysis. Snow and ice actions Part ws The standard also sets out minimum detailing requirements that aim to provide buildings with a reasonable level of ductility.
This is required for the highest hazard levels and tallest structures. The examples assume that at least a static analysis has been selected, and therefore, sets out the data required to calculate the base shear.
AS Earthquake actions in Australia Worked examples_百度文库
The 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: 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.
It is calculated by a simple equation given in Section 6 of the Standard. Determining the period of an existing structure, however, is a simple exercise involving measuring its vibrations.
The ductility is achieved by applying the detailing provided in the materials design Standards currently in use. The soil type is determined by a geotechnical investigation for taller longer period structures. The Table below shows how for many structures, there are points at which no further work is required.
AS – Australian Earthquake Engineering Society
Also, as a result of the lower earthquake loads expected, the detailing required is minimal compared to that for such countries as New Zealand. The base shear may be understood to be the percentage of the weight of the building to be applied laterally eg. Many structures do not require this level of design effort as there are conditions for which no further work is required by the Standard.
Walls will usually require a check of the resistance to face loading. Analysis of az structure is not covered.
One of the fundamental principles of this approach is the removal of hidden factors through the provision of an umbrella document that defines the loading and resistance levels for design using the design event approach.
Quick paths to an exit If you are ax one of the following structures, you can exit quickly to a simplified solution or even out of the Earthquake Standard altogether: Materials design Standards then provide detailing to enable the selected structural ductility to be achieved. Spectral shape factor site hazard spectrum The period is then used to determine the spectral shape factor Ch T1 for the building on the site.
Process of designing for earthquake actions Earthquake actions are determined by considering the site hazard and the type 1170.4 configuration of the structure. If they do, the structure will 1170. exhibit the ductility required of it and will therefore attract a much higher load than that for which it is designed.
AS 1170.4_Earthquake Actions in Australia_2007.pdf
The Standard assumes that structures are irregular as the 1170.44 majority of structures in Australia fail to achieve regularity. The equation is based essentially on the height of the structure, but includes an adjustment for material type. The a design Standards are then used to design the members for the required resistance including achieving the ductility assumed in determining the loads.
Earthquake actions in Australia AS The loads on the structure are then calculated based on this value. The material in which the structure is laterally coupled to the ground provides the site class.