My colleagues and I published two papers in the recent ACI SP-323 “Evaluation of Concrete Bridge Behavior through Load Testing – International Perspectives”, of which Dr. Pinar Okumus and myself were coeditors.
The two papers are:
SP-323—1: ASSESSMENT OF SLAB BRIDGES THROUGH PROOF LOADING IN THE NETHERLANDS
Eva O. L. Lantsoght, Cor van der Veen, Ane de Boer and Dick A. Hordijk
A large subset of the Dutch bridge stock consists of reinforced concrete slab bridges, for which assessment often results in low ratings. To prioritize the efforts of the bridge owner, more suitable assessment methods for slab bridges are necessary. Research efforts over the past years resulted in the development of several methods, at levels requiring increasing costs, time, and effort for increasing accuracy. The last option, when an analytical assessment is not possible due to uncertainties, is to use proof load testing to evaluate the bridge directly. To develop recommendations for the proof load testing of reinforced concrete slab bridges for the Netherlands, different methods are combined: pilot proof load tests on bridges with and without material damage, a collapse test, tests on beams taken from an existing bridge and new beams with similar dimensions cast in the laboratory, and an extensive literature review. The result of this study is a set of recommendations that describe how to prepare and execute a proof load test, and how to analyze the results. This paper summarizes the research program about proof load testing from the Netherlands and gives an overview of the currently developed recommendations and topics for further research.
SP-323-3: RATING OF CONCRETE ROAD BRIDGES WITH STATIC PROOF LOAD TESTS
Anna Halicka, Dick A. Hordijk, Eva O.L. Lantsoght
Nowadays, finite element analyses provide information about the performance of a structure, but they are more or less simplified. Therefore, load tests are the only way to find the “real” behavior of an existing bridge subjected to the rating process. In this paper, the state-of-the-art concerning load tests of concrete road bridges is presented, and the problems of the execution of such tests are specified. It is pointed out that only load tests accompanied with current finite element analyses may result in a proper assessment of the level of safety of the bridge. The authors’ procedure of complex assessment of such bridges combines in-situ examination of the structure, load testing, and finite element modeling.
The paper discusses the following topics:
• Aims and fundamentals of static diagnostic and proof load tests,
• The load application method according to different codes and specifications,
• The basis for proper assessment of the target load: reliability index, partial factors approach, global rating factor approach,
• Establishing the load allowable on the bridge, based on the applied proof load,
• The proposed procedure of assessment of existing concrete road bridges by load testing.
Keywords: codes of practice; field testing; finite element modeling; load testing; measurements; proof load testing; reinforced concrete bridges