Bridge pier scour measurement by means of Bragg grating arrays

Abstract. This paper deals with a new method to measure scour level at bridge piers. The proposed technique is based on an array of Bragg grating temperature sensors, heated by an electrical circuit. The Bragg gratings in water sense a lower temperature than those buried in the river bed, because of the different heat scattering principles in the two situations. Furthermore the response of each sensor is slower if it is buried in the bed, with respect to the case it is in water. The paper presents laboratory tests, showing the method effectiveness and reliability, and it explains the advantages with respect to other more traditional methodologies to measure scour level

Ex post damage assessment: an Italian experience

In recent years, awareness of a need for more effective disaster data collection, storage, and sharing of analyses has developed in many parts of the world. In line with this advance, Italian local authorities have expressed the need for enhanced methods and procedures for post-event damage assessment in order to obtain data that can serve numerous purposes: to create a reliable and consistent database on the basis of which damage models can be defined or validated; and to supply a comprehensive scenario of flooding impacts according to which priorities can be identified during the emergency and recovery phase, and the compensation due to citizens from insurers or local authorities can be established. This paper studies this context, and describes ongoing activities in the Umbria and Sicily regions of Italy intended to identifying new tools and procedures for flood damage data surveys and storage in the aftermath of floods. In the first part of the paper, the current procedures for data gathering in Italy are analysed. The analysis shows that the available knowledge does not enable the definition or validation of damage curves, as information is poor, fragmented, and inconsistent. A new procedure for data collection and storage is therefore proposed. The entire analysis was carried out at a local level for the residential and commercial sectors only. The objective of the next steps for the research in the short term will be (i) to extend the procedure to other types of damage, and (ii) to make the procedure operational with the Italian Civil Protection system. The long-term aim is to develop specific depth–damage curves for Italian contexts

Direct damage controlled seismic design of plane steel degrading frames

A new method for seismic design of plane steel moment resisting framed structures is developed. This method is able to control damage at all levels of performance in a direct manner. More specifically, the method: (a) can determine damage in any member or the whole of a designed structure under any given seismic load, (b) can dimension a structure for a given seismic load and desired level of damage and (c) can determine the maximum seismic load a designed structure can sustain in order to exhibit a desired level of damage. In order to accomplish these things, an appropriate seismic damage index is used that takes into account the interaction between axial force and bending moment at a section, strength and stiffness degradation as well as low cycle fatigue. Then, damage scales are constructed on the basis of extensive parametric studies involving a large number of frames exhibiting cyclic strength and stiffness degradation and a large number of seismic motions and using the above damage index for damage determination. Some numerical examples are presented to illustrate the proposed method and demonstrate its advantages against other methods of seismic design. © 2014, Springer Science+Business Media Dordrecht

Actions monitoring as an alternative to structural rehabilitation: Case study of a river bridge

A number of river bridges collapse worldwide every year during flood events, due to combination of actions including traffic loads, water and wind load, riverbed degradation, and accumulation of debris. Incidence of failure is higher for relatively old bridges that may have been designed without adequate consideration for some of such actions, in particular the scour potential at piers and abutments; in this case, consolidation of bridge foundations may be required. As an alternative to structural rehabilitation, we propose here real-time management as a nonstructural risk-mitigation measure: Data from a monitoring system aid the bridge managers to decide whether a bridge should be partially or totally closed to traffic in the case that forecasted environmental conditions indicate that the structure may exit its safe operational domain. A peculiar feature of the present proposal is that the monitoring system focuses on the evaluation of the environmental actions on the structure rather than on the health state of the structure itself: Such choice allows sufficient lead time for bridge closure. Bridge management may not prevent the damage of the structure but should avoid casualties. The methodology is presented with reference to the field case of a bridge over the river Po (Italy); its generalization to a larger variety of conditions is also discussed

The Park Tower in Milan: A steel structure of 1933 in the light of past and present knowledge. Part 1

none2G. Ballio; G. SolariG., Ballio; Solari, Giovann