In the wake of recent strong earthquakes in Croatia, there is a need for a detailed and more comprehensive post-earthquake damage assessment. Given that masonry structures are highly vulnerable to horizontal actions caused by earthquakes and a majority of the Croatian building stock is made of masonry, this field is particularly important for Croatia. In this paper, a complete assessment of an educational building in Zagreb Lower Town is reported. An extensive program of visual inspection and geometrical surveys has been planned and performed. Additionally, an in situ shear strength test is presented. After extensive fieldwork, collected data and results were input in 3Muri software for structural modeling. Moreover, a non-linear static (pushover) analysis was performed to individuate the possible failure mechanisms and to compare real-life damage to software results.

In 2020, Croatia was struck by two catastrophic earthquakes, resulting in more than 50,000 damaged structures. The majority of these are masonry buildings, but there are a number of reinforced concrete structures that suffered moderate to extensive damage. In this paper, the seismic condition assessment and upgrading of existing RC structures are presented with a case study building in Zagreb. The assessment procedure includes initial visual inspection, rapid preliminary evaluation, detailed in situ measurements, and non- and semi-destructive methods. New technologies were applied and followed by numerical modeling and verifications. Strengthening proposals are made that respect owner needs and the needs for the energy retrofitting of the existing RC building. As the integrated approach should be respected in the renovation of existing buildings, this case study can represent an example of good practice in the process of seismic and energy retrofitting.

In the last decades, the post-earthquake assessment and strengthening of existing structures are becoming one of the most critical fields of civil engineering. Most parts of Europe, as well as many existing buildings in Croatia, are built in masonry. For that reason, the main objective of this paper is to show the role of updating knowledge in the decision analysis process of existing masonry assessment. Collecting information through condition assessment can be performed on multiple levels with different precision and quality of the obtained data. Several alternative maintenance strategies and corresponding outcomes usually represent decision problems regarding the assessment of existing structures. Regarding existing buildings, decision analysis proved the benefits of updating knowledge in the building post-earthquake assessment process. As case studies, two existing masonry buildings were selected and different assessment procedures and decision scenarios were presented. The Value of Information (VoI) analysis showed that the applied method is feasible from the perspective of owners and users, as its implementation resulted in a reduction in the overall strengthening and maintenance costs.

The 2020 earthquakes in Croatia have highlighted the need for rapid assessment methods of buildings, particularly for unreinforced masonry (URM) structures, which are highly susceptible to seismic activity. Large-scale assessment methods that address a large number of buildings need to be expeditious and are typically based on a few vulnerability indicators related to the building characteristics. Acknowledging that existing methods may not be adequate for all building typologies in different geographical regions, this research aims to adapt them to create a tailored vulnerability assessment method for URM buildings in continental Croatia. Detailed information on the characteristics, typology, and architectural design of Croatian URM buildings is currently limited, however, collecting such data is essential for performing reliable seismic vulnerability assessments. The proposed method involves the development of a taxonomy for typical Croatian URM building typologies, enabling a rapid evaluation of their seismic vulnerability based on key data parameters. Sensitivity analysis was done to refine the understanding of their impact of these parameters on the seismic behaviour of these buildings. Results were validated through nonlinear simulations and actual damage observations from recent earthquakes. The proposal for new expeditious index-based method tailored for Croatian building stock is presented and validated with real data after seismic event.

In Europe, as well as in Croatia, the topic of seismic resistance assessment is very relevant due to a large number of seismically active areas. This paper presents the possibility of using modern tools in assessing the seismic resistance of buildings. Using Grasshopper, a parametric software package contained in Rhinoceros 3D, the impact of conceptual design on structural behavior is analyzed. The analysis of geometrical characteristics of structures according to the regularity criteria set in Eurocode 1998-1 is carried out. The most important examined parameters are symmetry, compactness, slenderness of the floor plan and eccentricity of the construction. Also, the work is focused on optimizing the floor plan of existing structures. The goal of optimization is to reduce the distance between the center of mass and the center of rigidity of the building floor plan in order to reduce the impact of torsion on the structure. The paper examines the possibilities of using parametric programming and lays the foundations for further research.