2024 - 2025
Antonio Formisano
Marco Domaneschi
Manuela Almeida
Firas Al Mahmoud
Fabrizio Ascione
Giuseppe Carlo Marano
+1 more
2024 - 2025
REsilient and SUstainable envelope for vulnerable buildings in seisMic affected areas at the time of climatE crisis
RESUME
Dataset Description
The RESUME project (REsilient and SUstainable envelope for vulnerable buildings in seisMic affected areas at the time of climatE crisis) addresses the urgent need to retrofit vulnerable reinforced concrete (RC) buildings in seismic-prone regions, enhancing both seismic resilience and energy efficiency. This dataset includes experimental shaking table tests conducted at the Institute of Earthquake Engineering and Engineering Seismology (IZIIS) in Skopje, Republic of North Macedonia. The experiments utilized 1:3 scale models of two-story RC frames, designed to replicate structures not originally designed for seismic loads, tested in both as-built and retrofitted conditions.
The retrofitting solution features an innovative, dry-assembled exoskeleton system integrating laminated timber and aluminium alloy components representing shear panels, supplemented with cork panels for thermal insulation. The testing protocol encompassed a range of seismic excitations, from low-intensity random vibrations to high-intensity scaled earthquake records.
The dataset includes time-history records of structural responses, such as accelerations, absolute and relative displacements, and strains, alongside photographic and video documentation capturing damage progression and system performance, as well as material testing reports detailing the mechanical properties of the components used in both the original and retrofitted configurations.
This dataset is a valuable resource for researchers and engineers, offering insights into the efficacy of integrated retrofitting strategies. It supports the validation of numerical models (e.g., modal and pushover analyses), the development of design guidelines for sustainable retrofitting systems, and advancements in combined seismic-energy vulnerability assessments.
Specimens
1. Model Y
2
Model Y is a 1:3 scale two-storey reinforced concrete frame structure. It consists of two longitudinal frames spaced 1.4 meters apart, connected transversely by reinforced concrete slabs and edge beams. The total length of the model is 4.2 meters, with a ground floor height of 1.5 meters and an upper floor height of 1.0 meter. Columns have square cross-sections of 10 × 10 cm, and beams are 10 × 15 cm. Longitudinal reinforcement consists of Ø8 bars placed at the corners of both columns and beams, with Ø4 stirrups at 10 cm spacing. Hollow brick infill walls, 10 cm thick, are installed in the end bays along the longitudinal direction. Two reinforced concrete slabs, each 6 cm thick, are cast at heights of 1.5 m and 2.5 m. The slabs are reinforced with Ø6 bars spaced at 7 cm in both orthogonal directions, placed in both top and bottom zones. The lower slab at 1.5 meters includes an opening in the central module for experimental access, while the upper slab at 2.5 meters covers the entire floor area. The model is supported on reinforced concrete strip footings: 85 × 25 cm in the longitudinal direction, reinforced with 11Ø10 bars in both top and bottom zones, and 80 × 25 cm at the transverse ends, reinforced with 10Ø10 bars. All footings include Ø4 stirrups spaced at 10 cm. A vertical load of 3200 kg is applied using eight steel blocks placed on the upper slab.
After the completion of initial dynamic testing, the model was retrofitted with a strengthening system combining laminated timber, aluminum, cork insulation, and steel components. The exoskeleton consists of timber frames connected using galvanized steel plates and screws. It is anchored to the existing reinforced concrete structure with steel pins installed at the beam-column joints and at the foundation strips, ensuring a stable and flexible connection. The system is installed on all exterior façades, except for the central longitudinal bay, which remains uncovered to allow visual inspection and monitoring during testing. A key component of the system is the use of 2 mm thick aluminum shear panels, which act similarly to structural walls and improve seismic performance by increasing stiffness and energy dissipation. Galvanized steel angles are used to connect the aluminum panels to the timber frame. These connections also allow for the installation of recycled cork insulation panels, which enhance thermal performance and contribute to environmental sustainability.
1. Phase 1 – Model Y
In this phase, Model Y was tested in its original, unstrengthened condition. The experiment began with a series of random excitations with increasing amplitude, followed by seismic excitations using scaled versions of three ground motions: Adana 1998, Umbria 2016, and a synthetically generated earthquake based on Eurocode 8 spectrum. Input intensity was gradually increased up to 140% of the synthetic motion. Visible damage appeared at 100%, including detachment of infill walls and cracking of the RC frame. By the end of the phase, approximately 80% of the ground floor infill collapsed and the dominant frequency dropped by about 80%, indicating a significant loss of global stiffness.
Instrumentation
The instrumentation included 12 accelerometers mounted at multiple levels and in both horizontal directions, 4 linear potentiometers installed at slab levels for interstorey displacement, 10 LVDTs placed between the shake table and the structure and around beam-column joints, and 30 strain gauges. Of the strain gauges, 24 were installed on reinforcement bars at different heights in the columns, and 6 were positioned directly on the surface of the concrete columns. All sensors were active during this phase.
2. Phase 2 - Model Y
In this phase, the previously damaged Model Y was retrofitted with an externally mounted exoskeleton system. Before installation, the damaged infill walls on the ground floor were reconstructed. The strengthened model was subjected to the same sequence of random and seismic excitations as in Phase 1. Input intensity was gradually increased up to 180% of the synthetic ground motion. No visual damage was observed up to 120%, after which localized detachment of infill walls and cracking of the RC frame were noted. Approximately 10% of the ground floor infill collapsed by the end of the phase. The recorded dominant frequency dropped by around 35% compared to the initial state of this phase, indicating improved performance compared to the bare frame.
Instrumentation
The setup included 15 accelerometers, of which 12 were used in Phase 1 and 3 were newly installed on the timber elements of the exoskeleton. Additionally, 4 linear potentiometers were placed at the slab levels to measure interstorey displacement, and 10 LVDTs were positioned between the structure and the shake table and around the beam-column joints. Out of 30 installed strain gauges, only the 24 attached to reinforcement bars were active during this phase, while the 6 mounted on concrete surfaces were not in use.
2. Model X
1
Model X is identical to Model Y in terms of geometry, reinforcement layout, infill wall configuration, slab arrangement, and applied vertical load. The only difference is that the exoskeleton system was installed before the start of testing, as an integral part of the initial construction, rather than as a retrofit applied after damage.
1. Phase 3 - Model X
In this phase, Model X was tested with the exoskeleton system installed from the beginning. The same sequence of random and seismic excitations as in the previous phases was applied, with increasing input intensity up to 200% of the synthetic ground motion. No significant damage was observed up to 120%. After 140% excitation, detachment of infill walls and minor cracking at column corners were recorded. At 180% and 200%, partial collapse of infill occurred, but the exoskeleton remained intact. Due to the shake table's displacement capacity, no higher inputs were possible. The final stage included random excitations in the 4–12 Hz frequency range. By the end of testing, approximately 30% of the ground floor infill had collapsed, while the global frequency dropped by about 50% from the initial value.
Instrumentation
The instrumentation was identical to that in Phase 2, including 15 accelerometers (with 3 on the timber elements), 4 linear potentiometers at slab levels, and 10 LVDTs placed between the structure and the shake table and around beam-column joints. All 24 strain gauges installed on reinforcement bars were active. Out of the 6 strain gauges intended for installation on the concrete surface of the columns, only 4 were mounted on central columns. The remaining 2, planned for the end columns, could not be installed due to lack of access caused by the exoskeleton frame.
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Creative Commons Attribution 4.0 International.
CC BY 4.0
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