Building instrumentation

• Main Author: Skolnik, Derek
• Format: Dissertation
• Language: English
• Subjects: engineering, civil
• ISBN: 9781109120912; 1109120915

Tall building construction in urban centers along the US west coast has recently surged and a significant number of the proposed buildings are being designed using alternative structural systems citing Chapter 16 of ASCE 7. These designs typically involve nonlinear dynamic analyses of 3D finite element models and require peer-review. The City of Los Angeles requires minimal instrumentation (e.g., accelerometers at the base, mid-level, and roof) for all buildings over ten stories. Recently, new instrumentation specifications have been implemented that specifically aim to increase the quantity and quality of instruments for these alternatively designed buildings. Systematic instrumentation of these structures will provide valuable data to (1) help address fundamental issues exposed during the peer review process, (2) enhance databases comprised of currently instrumented structures which are subsets of larger databases established from strong motion instrumentation programs (SMIPs), and (3) establish a unique testbed to develop and implement a network for structural health monitoring and probabilistic post-event assessment enabled through performance-based earthquake engineering (PBEE) tools (e.g., fragility functions). Due to the diversity of SMIP governing agencies and along with the fact that building instrumentation is typically secondary to the ground motion monitoring imperative, uniform specifications for structural instrumentation are lacking. Although recommendations have recently been made, they are generally based on qualitative assessments and experience. To this end, a qualitative basis for building instrumentation specifications, namely sample rate, resolution, and channel-to-channel synchronization is established through simulations of data acquisition errors and sensitivity analyses with respect to important engineering response quantities (e.g., interstory drift ratio---IDR). Incidentally, IDR is a particularly useful response quantity within the PBEE framework. However, current methods for measuring IDR (e.g., double integration of acceleration) are problematic, as shown using data from full-scale forced vibrations studies. Two novel sensors are prototyped and tested on a small-scale laboratory structure. Preliminary data from shake table studies reveal promise for a non-contact interstory displacement sensor and outline future endeavors.