ISO 16711:2021 pdf download – Requirements for seismic assessment and retrofit of concrete structures.
4 Framework of assessment and retrofit The seismic assessment and retrofit of an existing structure shall obey the following procedures after identifying the performance requirements and drafting an overall plan from investigation through detailed seismic assessment, construction and documentation. The schematic of the process is shown in Figure 1. Details of each item are described in Clause 5. All these items are not necessarily executed. The procedure should be initiated in order from 1) but it may be finished at any stage according to the specific situation under consideration. 1) Preliminary assessment: The possibility of a structure’s collapse or turnover under severe earthquakes shall be assessed based on the comprehensive information of the structure, such as design documents at the time of design, history of usage and the construction’s compliance with the design standard. The inspection of the seismic performance shall be carried out in consultation with the client (the owner, the authority, etc.), if the seismic performance is suspected or not clearly adequate. 2) Detailed seismic assessment: In order to clarify the seismic performance of an existing RC or PSC structure and the vulnerable part of the structure, detailed seismic assessment shall be conducted. Necessity of the seismic retrofit shall be determined by comparing the evaluated seismic performance and the seismic performance objectives. The planning of the seismic retrofit shall be carried out in consultation with the client (the owner, the authority, etc.), if the deficiency in seismic performance is confirmed. 3) Planning of seismic retrofit: The plan of the seismic retrofit including the outline of the retrofit and construction method shall be determined. The validity of the plan shall be verified by estimating the seismic performance of the structure after construction.
5 Preliminary assessment 5.1 General The preliminary inspection of a structure shall be conducted to judge the necessity of the detailed seismic assessment and retrofit of the structure in advance. In the preliminary inspection, necessary information to decide the execution of detailed seismic assessment and retrofit shall be collected by the inspection of the structure regarding the assessment items in 5.2. 5.2 Investigation items In principle, the following items shall be investigated in the preliminary investigation. 1) Year of construction: The date and year of design of the structure and the date and year of completion of the structure shall be investigated. NOTE 1 The year of construction helps to know the design standard by which the structure was designed, material properties, arrangement of reinforcement and structural details.