PSI - Issue 78

Emanuele Brunesi et al. / Procedia Structural Integrity 78 (2026) 161–168

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These structures, in spite of stemming from a relatively highly-standardised precast concrete technology, were and are still designed only for static loads, crane-induced loads and (very moderate) wind loads according to the Dutch National Annex of Eurocode (NEN 2011), which is the main local reference for design and which does not prescribe any permissible seismic performance parameter and/or level. This is essentially due to the fact that structures in the region of Groningen have never before been exposed to earthquake hazard, given that the region was historically not prone to natural/tectonic earthquakes. The above code/design scenario, involving the lack of seismic design prescriptions and criteria, obviously applies to the cast-in-place case too, with a photograph of the specimen representing this case being given in Figure 4, which also shows a schematic of test setup for cyclic testing in both longitudinal and transverse directions by means of four actuators for the application of lateral loads combined with four hydraulic jacks post-tensioned to the foundations for the application of downward gravity loads. The reader is not only referred to Figure 4 and Figure 5, where the specimen and only key construction details are shown, but also directly to Brunesi et al. (2018b) for a more in-depth discussion on cast-in-place terraced houses and related features the tested specimen was designed to resemble.

Fig. 4. Single-storey two-bay reinforced cast-in-place concrete specimen before cyclic testing and schematic of test setup.

Fig. 5. Asymmetric starter rebars and in-floor bent steel rebars in the wall-slab joints of cast-in-place building specimen.

According to common Dutch building practice, cast-in-situ terraced houses are generally one-storey or two-storey multi-unit tunnel-built structures, which make use of special formworks that enable modular and cost-effective construction. This technique permits walls and floors to be erected simultaneously by pouring the concrete in a unique formwork that can be moved forward for use in adjacent units, after the hardening of concrete. The floors are usually reinforced with a uniform layout reinforcement in the lower part consisting of longitudinal and transverse steel bars, whereas the upper reinforcement grid is placed where the moment is expected to be negative. Two layers of reinforcement composed of vertical and horizontal steel rebars are most commonly provided in the walls and, in the overwhelming majority of the cases, the outer layer is stronger than the inner one. As can be inferred from Figure 5, in-floor bent vertical rebars are generally used to ensure the continuity between the walls and the floors, and starter rebars protruding from the foundations are generally asymmetric and not always ribbed. It is also noteworthy that no mechanical connections are usually present between the first and second floors of a two-storey tunnel-built terraced house, which is another reason why a decision was made to test a single-storey cast-in-place specimen. Front and back façades of these buildings are generally cavity walls, whilst gable walls, if present, are usually prefabricated elements.