Computational modelling of a four storey post-tensioned concrete building subjected to shake table testing

Abstract

Prior research into low-damage wall systems has predominately focused on the walls behaviour in isolation from other building components. Although the response of these isolated walls has been shown to perform well when subjected to both cyclic and dynamic loading, uncertainty exists when considering the effect of interactions between walls and other structural and non-structural components on the seismic response and performance of entire buildings. To help address this uncertainty a computational model was developed to simulate the response of a full-scale four-storey building with post-tensioned precast concrete walls that was subjected to tri-axial earthquake demands on the E-Defence shake table. The model accurately captured the buildings measured response by incorporating the in-plane and out-of-plane non-linear behaviour of both the wall and floor elements. The model was able to simulate the deformation demands imposed on the floor due to compatibility with the post-tensioned walls, closely matching the behaviour and damage observed during the test. Dynamic loading and wall-to-floor interaction were shown to significantly increase the over-strength actions that developed when compared to the wall system considered in isolation.

Simulation of shake‐table test for a two‐story low‐damage concrete wall building

“…36 Damping ratios of 2% were used for the design-level earthquake (DBE) and maximum considered earthquake (MCE) intensities, which was similar to that used in comparable UPT building models. 22 A frequency analysis of the white noise excitation at the start of testing showed that the fundamental period of the test building with the D1a configuration was 0.35 s for the first translational mode in the transverse direction, and 0.21 s for the first translational mode in the longitudinal direction. The eigen analyses of the models revealed that the fundamental periods of the transverse and longitudinal direction frames with the D1a configuration were 0.24 and 0.16 s, respectively.…”

“…This modeling method has been verified in prior UPT wall simulation analysis. 18,22 The multispring model was proven to capture the mechanical behavior of slotted-beam joints in component-level experiments. 29 In the multi-spring model, the top concrete hinge region was modeled by macro multiple concrete springs and longitudinal and diagonal hanger reinforcement springs.…”

“…19 This shake table tests not only confirmed that the UPT walls are a suitable alternative to conventional reinforced concrete walls but also provided valuable data on the dynamic responses and system interactions of UPT walls. 20 Two separate numerical analyses of the E-defense test building conducted by Gavridou et al 21 and Watkins et al 22 both showed modeling of the component interactions, and in particular the wall-to-floor response, was critical to accurately assessing the building lateral strength and seismic response. However, studies on the overall building system response including dynamic loading and interaction of UPT walls with other components have still been relatively lacking.…”

Shake‐table test of a two‐storey low‐damage concrete wall building

“…Damage occurred at the wall‐to‐floor interface where the PT walls were monolithically connected to the topping of the precast floor units and crushing at the column bases occurred due to increased axial demands from outrigger framing action. A numerical model developed for the E‐defense test building showed that the inclusion of the beams connected between the wall and columns as well as in‐plane and out‐of‐plane response of the floors were essential to accurately capture the lateral‐load response of the entire building 27 . A separate unidirectional test of a three‐storey precast concrete building that incorporated hybrid PT walls was completed on the shake‐table at UC San Diego 28,29 .…”

“…A numerical model developed for the E-defense test building showed that the inclusion of the beams connected between the wall and columns as well as in-plane and out-of-plane response of the floors were essential to accurately capture the lateral-load response of the entire building. 27 A separate unidirectional test of a three-storey precast concrete building that incorporated hybrid PT walls was completed on the shake-table at UC San Diego. 28,29 Although the test primarily focused on the diaphragm response, the test confirmed that slotted connectors could be implemented between the wall and floor to enable horizontal force transfer while allowing unrestrained uplift of the PT walls.…”