A contribution to the development and improvement of the design codes is considered to be the key result of the research. In such a way the results bring by far the most multiplied effect in the practice, safety and economy. Already before the end of the project two pre-normative documents were published. The first one provides the guidelines for the design of a precast structure with cladding panels as a whole. This aspect of design has never been understood correctly. Designers typically considered that claddings did not interact with the structure in the direction in the plane of the panels. However the displacement tolerances do not allow for such assumption in the case of strong earthquakes. This led to serious damage and even collapses in the past. Even the designers were aware of this problems they would not have procedures and tools to address them properly. Based on the research presented in this report, the well needed guidelines providing the complete design process were published in the European Joint Research Centre technical report. Activities are going on to adopt parts of these rules in Eurocode 8.
F.31 Development of standards
COBISS.SI-ID: 7584097The second pre-normative document provides guidelines for the design of the specific connections between the precast cladding panels and the structure. These connections were designed (if they were at all) for the out-of-plane action. But, as it was described in the previous section, they were never designed for the in-plane action. Actually, the complex 3D interaction is a complex mechanism, which the designers were not able to address. However, the performance and safety of the cladding systems depends predominately on these connections. The fact that many different types of connections are used in the design practice further complicates the problem. Therefore, the design guidelines, procedures and formulas were prepared for the most typical connections used in Europe. The document is based on the in-depth understanding of the complex seismic behaviour of the connections, which has been obtained in this project. The document was published in the European Joint Research Centre technical report. Activities are going on to adopt parts of these rules in Eurocode 8.
F.31 Development of standards
COBISS.SI-ID: 7588193The world-wide well-known company HILTI organizes regular seminars for practicing engineers. Authors were invited to present the results of the recent research in the field of the seismic resistance and design of the typical connections in precast buildings. This was a good opportunity to directly disseminate results of the project.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 8616545The PI of this project organized a special session SS43 “Seismic behaviour of existing and innovative precast structural systems and connections” during the 16th World Conference of Earthquake Engineering. World conferences are attended by 4 thousands participants and therefore represent the biggest single event to disseminate results and knowledge worldwide. After the review 16 papers were selected (3 of which were contributed by the research team) and presented whithin 2 two-hours sessions, which were well attended. The topics related to this project were discussed in detail and the results of the project arised considerable interest.
B.01 Organiser of a scientific meeting
In the dissertation, an original methodology was developed for conducting seismic stress tests for precast reinforced concrete buildings on the basis of target seismic risk. The methodology includes both seismic risk analysis and a grading system, which is based on a comparison of the assessed risk with different risk acceptance boundaries. Based on the grades obtained in the grading process, the outcome of the stress test is determined. The possible outcomes are: "pass" (grades AA and A), "partly pass" (grade B), and "fail" (grade C). The stress test can be conducted at two different reliability levels, which differ in the number of seismic response analyses required. The stress test at the higher reliability level was applied to three single-storey precast reinforced concrete buildings with inadequate connections and different types of non-structural elements (vertical panels, horizontal panels, and masonry infills). The outcome of the stress test was negative in all cases, the worst performance being observed in the case of the building with vertical panels. This building was also used in the stress test at the lower reliability level. In this case, less than one percent of all the analyses required at the higher level were conducted; however, the results obtained at the two reliability levels were practically the same. Additionally, seismic stress tests can also be used at the level of systems of buildings, if appropriate tools are available. To this end, fragility functions for twelve building classes, which are one of the inputs for the stress test at the systemic level, were derived. Such fragility functions also make possible comparisons between the seismic responses of different building types. Existing single-storey precast reinforced concrete buildings with inadequate seismic design were examined. It was found that non-structural elements increased seismic risk in the considered buildings by reducing the median collapse intensity and increasing its dispersion.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 8142689