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 in the Czech standard on assessment of existing structures. The 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.