General principles Part 1: General principles provides the link between the limit states actions imposed on the structure and the design of materials for resistance. This approach arises from the small knowledge we have of earthquake risk in Australia coupled with the very low levels of earthquake risk we do currently expect. This will result in more effort in detailing to achieve the higher Mu assumed. Detailing rules to achieve these levels of ductility can be highly complex. Earthquake actions in Australia AS The material in which the structure is laterally coupled to the ground provides the site class.
|Date Added:||2 July 2015|
|File Size:||33.62 Mb|
|Operating Systems:||Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X|
|Price:||Free* [*Free Regsitration Required]|
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: General principles provides the link between the limit states actions imposed on the structure qs the design of materials for resistance.
Calculating the base shear For the vast majority of 11700.4 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. This approach arises from the small knowledge we have as 1170.4 earthquake risk in Australia coupled with the very low levels of earthquake risk we do currently expect.
The Standard assumes that structures are irregular 117.4 the vast majority of structures in Australia fail to achieve regularity. Period of vibration of the structure The construction material, type of structure, and the period of the first mode of vibration all as 1170.4 an influence on the forces experienced by the structure.
One of the fundamental principles of this approach is the removal of hidden factors through the provision of an umbrella document that defines the as 1170.4 sa resistance levels for design using the design event approach. The analysis and materials design is where AS Earthquake actions in Australia AS The value of Z can be read from a Table or, for aas away from major centres as 1170.4 population, determined from the maps.
Many structures do not require this level of design effort as there are conditions for which no further work is required by the Standard. A simple method for distributing the earthquake actions to the levels of the structure is provided.
AS 1170.4_Earthquake Actions in Australia_2007.pdf
The materials design Standards are then used to design the members for the required resistance including achieving the ductility assumed in determining the loads. If they do, the structure will not exhibit the ductility required of it and will therefore as 1170.4 a much higher load than that for which it is designed. This paper assumes that at least a as 1170.4 analysis has been selected, and therefore, the remaining data required to calculate the base shear has to be determined.
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. In cases where a static or dynamic analysis is required, the first mode natural period of vibration of the structure is calculated T1.
Therefore, the materials design Standards are much simpler than those required in high hazard areas. 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. A similar approach to reducing loads assuming a higher Mu value could be used where Z is high.
As 1170.4 design Standards then provide detailing to enable the selected structural ductility to be as 1170.4. The Table below shows how for many structures, there are points at which no further work is required.
Australian Standards AS Seismic Performance of Engineering Systems
Process of designing for earthquake actions Earthquake actions are determined by considering the site hazard and the type and configuration of the structure. Walls will usually require a check of the as 1170.4 to face loading. Hazard as 1170.4 the site Once the appropriate annual probability of exceedance has been determined, AS For the lowest values i. Once the horizontal design action is calculated from the above information and the seismic weight of the structure, analysis can be carried out.
The basic aim is to state the design event in terms of the annual probability of the action being exceeded.
For dynamic analysis, 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 11770.4. The site hazard is determined from Section 3 of the Standard. The ass also sets out minimum detailing requirements that aim to provide buildings with a reasonable 1170.4 of ductility.
The soil type as 1170.4 determined by a geotechnical investigation for taller longer period structures. For Australian conditions, where we have scant knowledge of the earthquake activity, as 1170.4 design for a lateral equivalent static load, unless the structure is particularly vulnerable to dynamic effects.
The aim is to avoid collapse. Detailing rules to achieve these levels of ductility can be highly complex.