The Streicker Bridge at Princeton Campus connects the science facilities (Icahn Lab with Jadwin Hall and the new Chemistry building) as well as west-side dormitories with athletics facilities. The bridge’s overall design was made by a world-renowned bridge designer from Switzerland Christian Menn. HNTB Corporation performed the detailed design and Turner Construction Company is the main contractor. Supervision and coordination have been carried out by the representatives from the Office of Design and Construction of Princeton University. The Bridge consists of a main span and four approaching ramps, so-called legs. Structurally, the main span is a deck-stiffened arch and the legs are curved continuous girders supported by steel columns. Legs are horizontally curved and the shape of the main span follows the curvature. The arch is built of steel while the main deck and legs are built of reinforced post-tensioned concrete.
The SHM of Streicker Bridge is a long-term project and it will be realized in several phases. The initial phase consists of instrumentation of the main span and southeast leg. The instrumentation of the main span was completed on August 14, 2009, with two fiber-optic sensing technologies: Discrete Fiber Bragg-Grating (FBG) long-gage sensing technology (average strain and temperature measurements); truly distributed sensing technology based on Brillouin Optical Time Domain Analysis (average strain and temperature measurements). The sensors were embedded in concrete during the construction.
Aim of monitoring:
SHM Lab decided to instrument the bridge with various sensors and transform it into an on-site laboratory for various research and educational purposes. The main aims of the instrumentation are to face the following challenges related to SHM: The education gap. Despite its importance, the culture of SHM is not yet widespread. It is often considered an accessory activity that does not require specific skills and detailed planning, while the facts are rather the opposite. Real structural behavior data sets. The complete data sets collected over long terms are needed to fully understand real structural behavior and its interaction with the environment. The SHM was applied to various types of structures, but the results of monitoring are frequently only partially disclosed or incomplete, thus the knowledge basis is rather deficient. Change in strain patterns caused by unusual behaviors. The patterns of degradation in performance and damage in monitoring results are often “masked” by environmental influences (temperature, wind, humidity, etc.) and human-made actions (live load fluctuations) and consequently, cannot be reliably identified in controlled laboratory conditions. More real data with unusual behaviors are needed to develop reliable detection algorithms. Characterization of SHM contribution to the sustainability of the built environment. SHM has promising potential to contribute to the sustainability of the built environment since it provides objective information concerning the real structural performance, which can be used as an input to optimize maintenance, extend the structure’s life, increase safety, decrease life-cycle costs, reduce the use of construction material, minimize adverse impact on society that may occur in case of structural deficiency, and help reducing greenhouse gas emissions. Besides addressing the above-listed challenges, the Streicker Bridge will be used for full-scale testing of new SHM methods, and newly developed monitoring systems.
|INSTALLATION PERIOD||TYPE OF SENSORS||NUMBER OF SENSORS|
|2009||DiTeSt / DiTemp , MuST||56|
Scientific contributions. Monitoring results will increase knowledge basis concerning the real structural behavior and help to build reliable algorithms for damage and performance degradation detection based on objective data. In addition, future sensing technologies and methods will be installed and tested on the bridge. The influence of SHM on the improvement of long-term bridge management and decrease of life-cycle costs will be evaluated and the SHM contribution to the sustainability of the built environment will be assessed. The results may have a potential impact in several other fields of civil engineering such as numerical modeling, structural analysis, life-cycle performance, and materials science. Educational contributions. The SHM of Streicker Bridge will be of significant support to the newly introduced graduate course CEE 539 on SHM – students will be involved in all phases of the project including the design of monitoring strategy, installation of the system, and data handling, interpretation, and analysis. Besides the course on SHM, the instrumented bridge will be of great support to the other departmental courses such as the newly introduced Theory of Structures, and existing courses on Mechanics of Solids, Structural Analysis, etc. Broader impact. The Bridge itself will be transformed into a laboratory that will serve not only for scientific and courses purposes, but will also be used for demonstration purposes to K-12, the public, policymakers (e.g. students of Woodrow Wilson School as future policymakers), and decision-makers from various administrative units (e.g. departments of transportation – DOT). Finally, increased safety for the bridge users and improved management for the bridge owner are expected.