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This project provides an in-depth study into how floor isolation systems (FISs) perform when subjected to floor accelerations from a 3D building model of a special concentrically steel braced frame (SCSBF) building during real-time hybrid simulation (RTHS). The project details the creation and study of a 3D model of a SCSBF building using HyCoM-3D, a 3D modeling software created for use at the NHERI Lehigh Experimental Facility. Data in this project can be reused to further assess how FISs behave when subjected to accelerations and their ability to isolate large nonstructural components of buildings and lessen their damage when subjected to different accelerations due to different building configurations. This project is unique because it considers the multi-directional response of a FIS subjected to floor motions simulated from a 3D, nonlinear model of a SCSBF building. The main audience is researchers and professionals interested in learning more about how FISs can limit damage to nonstructural building components.
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When will an elevator arrive?
Abstract We present and analyze a minimalist model for the vertical transport of people in a tall building by elevators. We focus on start-of-day operation in which people arrive at the ground floor of the building at a fixed rate. When an elevator arrives on the ground floor, passengers enter until the elevator capacity is reached, and then they are transported to their destination floors. We determine the distribution of times that each person waits until an elevator arrives, the number of people waiting for elevators, and transition to synchrony for multiple elevators when the arrival rate of people is sufficiently large. We validate many of our predictions by event-driven simulations.
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- PAR ID:
- 10315315
- Date Published:
- Journal Name:
- Journal of Statistical Mechanics: Theory and Experiment
- Volume:
- 2021
- Issue:
- 4
- ISSN:
- 1742-5468
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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null (Ed.)Floor isolation systems (FISs) are used to mitigate earthquake-induced damage to sensitive building contents and equipment. Traditionally, the isolated floor and the primary building structure (PS) are analyzed independently, assuming the PS response is uncoupled from the FIS response. Dynamic coupling may be non-negligible when nonlinearities are present under large deflections at strong disturbance levels. This study investigates a multi-functional FIS that functions primarily as an isolator (i.e., attenuating total acceleration sustained by the isolated equipment) at low-to-moderate disturbance levels, and then passively adapt under strong disturbances to function as a nonlinear (vibro-impact) dynamic vibration absorbers to protect the PS (i.e., reducing inter-story drifts). The FIS, therefore, functions as a dual-model vibration isolator/absorber system, with displacement dependent response adaptation. A scale experimental model—consisting of a three-story frame and an isolated mass—is used to demonstrate and evaluate the design methodology via shake table tests. The properties of the 3D-printed rolling pendulum (RP) bearing, the seismic gap, and the impact mechanism are optimized to achieve the desired dual-mode performance. A suite of four ground motions with varying spectral qualities are used, and their amplitudes are scaled to represent various hazards—from service level earthquake (SLE), to design basis earthquake (DBE), and even maximum considered earthquake (MCE). The performance of the multi-functional FIS is established and is described in this paper.more » « less
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ABSTRACT This study integrates analytical and experimental research to develop an innovative shake table testing method called Floor Acceleration Simulation Test (FAST). The primary objective of FAST is to produce an essentially elastic response of a single‐story test specimen to replicate the floor acceleration time history including higher‐mode effects of a target floor in a multistory building experiencing inelastic behavior during an earthquake. The FAST method is well suited for experimental research where the absolute accelerations and the associated inertial forces of the floor diaphragms cannot be simulated by the majority of the conventional test methods. The proposed methodology is based on a transfer function in the frequency domain to compute the required input motion for testing. Considering the physical constraints of a given shake table test facility, guidelines with two response spectra to bracket the natural frequency of the test building are also presented for practical implementation. Experimental validation was carried out on a half‐scale, single‐story steel building featuring a composite floor slab, utilizing the NHERI@UCSD Large High‐Performance Outdoor Shake Table (LHPOST) facility. The results demonstrate the effectiveness of FAST, as both analytical predictions and experimental outcomes confirm its validity. Despite instances of measured floor acceleration amplitude exceeding the target response due to table input motion overshooting in this test program, test results confirmed that the FAST accurately reproduced the intended frequency content, indicative of higher mode effects in the multistory prototype building, in the single‐story test building.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1088/1742-5468/abf7b6
