Self-Centring seismic-RESilient sTEEL structures
ERIES-SC-RESTEEL
Dataset Description
The ERIES-SC-RESTEEL project investigates the seismic performance, repairability, and effective placement of low-damage self-centring (SC) joints for steel MRFs. The tested solution is based on dissipative and self-centring components to be included at column bases (CBs) and beam-to-column joints (BCJs) to dissipate the earthquake input energy and prevent residual drifts.
The dissipative connections consist of two parts connected by a combination of: (1) friction devices (FDs), which dissipate the seismic input energy through the alternate slippage of the surfaces in contact; and (2) PT bars with disk springs that control the self-centring behaviour of the connection.
Tests were conducted at the National Laboratory for Civil Engineering (LNEC), Lisbon, Portugal, on the ST3D shake table on a reduced-scale structure with 3 storeys, 1 bay in the x-direction, and 2 bays in the y-direction. The model scaling is based on the material and acceleration scaling identity, and a scaling factor of 0.6 was selected to respect the Lab constraints while allowing the correct reproduction of the seismic response of the joints. The interstorey heights are equal to 1.92 m at the first storey and 1.80 m at the intermediate storeys, while the longitudinal and transversal bays have span lengths equal to 3.50 m and 4.00 m, respectively.
Four configurations were tested, depending on the MRFs connections: (1) MRF ALL: low-damage and self-centring BCJs and CBs (including PT bars); (2) MRF CBs: low-damage and self-centring CBs (including PT bars) and low-damage BCJs (without PT bars); (3) MRF LD: low-damage BCJs and CBs (with untightened PT bars); (4) MRF LD2: same concept of MRF LD but removing PT bars from BCJs, loosening bolts at the base of gravity columns, removing Teflon from splice, tightening splice connection (now working as continuity connection) and controlled retightening of friction plates.
The research outputs demonstrated the structure's low damage and self-centring capability throughout the full test sequence.
Specimens
1. Steel MRF with low-damage self-centring joints
1
The test specimen for the shake table tests is a reduced-scale structure with 3 storeys, 1 bay in the x-direction, and 2 bays in the y-direction. The internal MRF is conceived to provide the lateral capacity, while the external frames are designed to carry gravity loads only. The storey heights are 1.92 m at the first level and 1.80 m at the upper levels, with bay spans of 3.50 m in the longitudinal direction and 2.00 m in the transverse direction. The specimen was extracted from a three-storey, three-bay prototype structure and scaled according to material and acceleration similitude with a scaling factor of λ = 0.6. Accordingly, length units were scaled by λ, areas and forces by λ^2, and time by λ^1/2.
The test specimen was designed in accordance with Eurocode 8. The design earthquake at the Ultimate Limit State (ULS) was defined using the Type 1 elastic response spectrum with PGA = 0.35g and soil type D. The Collapse Limit State (CLS) was assumed to correspond to 150% of the ULS. A behaviour factor of q = 6.5 was adopted for MRFs in Ductility Class High. The interstorey drift limit at the Damage Limit State (DLS) was set to 1% for non-structural elements not interfering with structural deformations. Beam and column cross-sections of the MRF were IPE240 and HEB180, of steel grade S355 (i.e., fy = 355 MPa), while the profiles of the gravity frames were IPE180 and HEA160, respectively. The floor system was a steel-concrete composite floor with a total height of 130 mm. The total mass of the specimen, including the additional masses (i.e., fixed to the slabs to simulate service load conditions) was 35.68 tons, compatible with the shake table capacity (< 40 t).
1. Shake-table test of four LD and SC configurations
Four different configurations of the MRF were investigated, considering BCJs and/or CBs with and without PT bars. Joints without PT bars are referred to as Low-Damage (LD) joints (LD-BCJs and LD-CBs), while those with PT bars are defined as Self-Centring (SC) joints (SC-BCJs and SC-CBs). Each configuration was tested in both LD and SC configurations.
Three GMs were selected, namely L’Aquila (pulse-like), Northridge (non-pulse-like) and Chi-Chi (non-pulse-like), to represent a broad range of seismic characteristics relevant for structural response, capturing both forward-directivity effects (pulse-like motions) and conventional far-field ground motions (non-pulse-like). The selected records were scaled in time (by λ^1/2) and at four increasing intensity levels, i.e., 15%, 40%, 66% (ULS), and 100% (CLS), for each configuration. Multiple tests were conducted at different intensities, resulting in approximately 150 tests in total. Each test was preceded by low-amplitude characterisation tests (i.e., white-noise excitations) to identify the structure’s dynamic properties, including natural periods and damping ratios. For selected configurations, some tests were carried out both with and without the vertical component of the ground motions, and additional repetitions were performed at the two reference intensity levels (ULS and CLS) to assess the repeatability of the structural response. Post-test inspections were conducted after the ULS and CLS runs to confirm the absence of significant structural damage.
Instrumentation
Instrumentation included accelerometers at storey levels, displacement transducers at storey levels and at beam-column joints, optical transducers and wire potentiometers for global floor displacements, strain gauges on the MRFs, and load cells on PT bars.
Project Metadata
Rights
Creative Commons Attribution 4.0 International.
CC BY 4.0
0 sessions
0 downloads
0 views
0 metadata
0 file previews
Feedback
We are always looking to improve the quality of our data and metadata. If you have any feedback or suggestions, please let us know.
Send Feedback