Survey of heritage structures, reliability assessment and subsequent design of appropriate interventions are disciplines where intensive multidisciplinary cooperation between architects, civil engineers and heritage preservation specialists is necessary. Surveys including visual inspections, measurements and tests provide vital information for reliability assessment. Non-destructive or minor-destructive tests are generally preferred in surveys of heritage structures. However, reliability assessments providing key information for decisions on structural interventions may require more detailed insights that may only be obtained by destructive tests. This is why incomplete information from a survey overly restricted to protect heritage values may lead to imprecise reliability assessment and to suboptimal decisions on structural interventions. As a consequence, such interventions may then lead to a loss of heritage value that might have been avoided. To provide guidance for practical applications, the submitted contribution presents an analysis of segments of heritage value that may be associated with buildings or bridges. Basis of the method was recently included into the Czech standard on assessment of existing structures. Sensitivity of each segment to the invasiveness of various methods of structural surveys is then discussed, considering also the potential need for input of reliability assessment. The presented framework is applied in the case study of a historic steel bridge located in the UNESCO site – historic centre of Prague. The contribution demonstrates that the segmentation of a heritage value by heritage preservation specialists and architects often helps to identify an optimal strategy for structural survey that provides sufficient information for detailed reliability assessment of the heritage structure. The case study presents a benchmark to be further developed and refined for its effective operational use in practice in the future.
analysis of heritage value, heritage structure, invasiveness, ISO 13822, reliability assessment, structural intervention
 Eberhardt, S. & Pospíšil, M., E-P Heritage Value Assessment Method. Proposed Meth- odology for Assessing Heritage Value of Load-Bearing Structures. International Jour- nal of Architectural Heritage, pp. 1–21, 2021. https://doi.org/10.1080/15583058.2021. 1901160
 Ryjáček, P., Assessment of historical steel bridges. Proc. SEMC 2019, eds. Zingoni A., CRC Press/Balkema: pp. 2176–2180, 2019.
 Ryjacek, P., The diagnostic techniques for the assessment of the historical steel bridges. IABSE Symp, pp. 1651–1657, 2019.
 Macho, M., Ryjáček, P. & Campos E Matos, J., Fatigue and corrosion as a threat for steel heritage bridges. IABSE Symp. 2018, IABSE: Zurich, pp. S29-81–S29-88, 2018.
 Plachy, T., Polak, M. & Ryjacek, P., Assessment of an Old Steel Railway Bridge Using Dynamic Tests. Procedia Engineering, eds. Romeo F., Gattulli V. & Vestroni F., Else- vier Ltd: pp. 3053–3058, 2017.
 CIB, Guide for the Structural Rehabilitation of Heritage Buildings (CIB Publication 335), CIB: Rotterdam, pp. 48, 2010.
 Sykora, M., Diamantidis, D., Müller, D. & Sousa, H., A Practical Guide on the Quantifi- cation of Value of Information Gained by Structural Health Monitoring and Application to Historic Masonry Structures. Structure and Infrastructure Engineering, pp. 1–15, 2020. https://doi.org/10.1080/15732479.2020.1857793
 Lenner, R., Ryjacek, P. & Sykora, M., Resistance Models for Semi-Probabilistic Assessment of Historic Steel Bridges. Proc. IABSE Symposium 2020, IABSE: Zürich, pp. 1061–1068, 2020.
 Sykora, M., Mlcoch, J. & Ryjacek, P., Uncertainties in Characteristic Strengths of His- toric Steels Using Non-Destructive Techniques. Transactions of the VSB – Technical University of Ostrava, Civil Engineering Series, 19(2), pp. 65–70, 2019. https://doi. org/10.35181/tces-2019-0022
 Jung, K., Markova, J., Pokorny, P. & Sykora, M., Material Properties of Heritage Wrought Steel Structure Based on Tests. International Journal of Heritage Architec- ture, 2(1), pp. 128–137, 2018. https://doi.org/10.2495/HA-V2-N1-128-137
 Jung, K., Markova, J. & Sykora, M., Evaluating Strength of Historic Cast Iron using Destructive and Non-destructive Tests. Beton- und Stahlbetonbau, 113(S2) - 16th Int. Probabilistic Workshop, 12–14 Sept 2018, pp. 141 (extended abstract, 5 p. full paper), 2018. https://doi.org/10.1002/best.201800059
 Jung, K., Markova, J. & Sykora, M., Optimising Surveys and Reliability Assessments of Historic Cast-Iron Columns. Proc. HPSM/OPTI 2018, eds. S. Hernandez, S. Kra- vanja & W.P. De Wilde, WIT Press: Ashurst Lodge, pp. 71–82, 2018.