The Standard also provides the means for reducing earthquake loads on a structure by achieving set levels of ductility. The equation is based essentially on the height of the structure, but includes an adjustment for material type. Process of designing for earthquake actions Earthquake actions are determined by considering the site hazard and the type and configuration of the structure. As with all the parts of the series, Part 0 provides the annual probabilities of exceedance or, for buildings covered by the BCA, refers the user to those provided in the BCA.
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The materials design Standards are then used to design the members for the required resistance including achieving the ductility assumed in ax the loads. This paper assumes that at least a static analysis has been selected, and 1170.44, the remaining data required to calculate the base shear has to be determined. It is calculated by a simple equation given in Section 6 of the Standard. The method of calculation given is the most reliable method available other than carrying out a full dynamic analysis and even then there are inherent modeling inaccuracies.
Once the horizontal design action is calculated from the above information and the seismic weight of the structure, analysis can be carried out. 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. The Standard assumes that structures are irregular as the vast majority of structures in Australia fail to achieve regularity.
For the lowest values 1170. The base shear may be understood to be the percentage of the weight of the building to be applied laterally eg. If they do, the structure will not exhibit the ductility required of it and will therefore attract a much higher load than that for which it is designed.
Process of designing for earthquake actions Earthquake actions are determined by considering the site hazard and the type and configuration of the structure. Earthquake actions in Australia.
AS 1170.4_Earthquake Actions in Australia_2007.pdf
For Australian 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.
Finally, the parts of the structure must be tied together and individually designed to perform. The motivation for this move is the GATT agreement and the reduction of technical barriers to trade. The ductility is achieved by applying the detailing provided in the materials design Standards currently in use. Detailing rules to achieve these levels of ductility can be highly complex.
In cases where a static or dynamic analysis is required, the first mode natural period of vibration of the structure is calculated T1. In the event that a structure is ad to an earthquake, the ductility provided 117.04 improves its performance, regardless of the actual magnitude of the earthquake and the actual design actions. The standard also sets out minimum detailing requirements that aim to provide buildings with a reasonable level of ductility.
Australian Standards AS Seismic Performance of Engineering Systems
The basic aim is to state the design event in terms of the annual probability of the action being exceeded. The loads on the structure are then calculated based on this value.
Hazard at the site Once the appropriate annual probability of exceedance has been determined, 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 Table 2. Therefore, the materials design Standards are much simpler than those required in high hazard areas. The soil type is determined by a geotechnical investigation for taller longer period structures.
Wind actions Part 3: Earlier this year CSIR Determining the period of an existing structure, however, is a simple exercise involving measuring its vibrations. Inter-storey drifts should be checked to ensure that parts such as stiff walls do not interfere with the seismic force resisting system.
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.
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. This value is then multiplied by the probability factor kp to determine the site hazard value kpZ for the appropriate annual probability of exceedance. Also, as a result of the lower earthquake loads expected, the detailing required is minimal compared to that for such countries as New Zealand.
In order to achieve the 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. The 11170.4 and materials design is where AS The key to understanding AS