Structural health monitoring for long span bridges : Hong Kong experience and continuing onto Australia

Structural health monitoring has been accepted as a justified effort for long-span bridges, which are critical to a region's economic vitality. As the most heavily instrumented bridge project in the world, WASHMS - Wind And Structural Health Monitoring System has been developed and installed on the cable-supported bridges in Hong Kong (Wong and Ni 2009a). This chapter aims to share some of the experience gained through the operations and studies on the application of WASHMS. It is concluded that Structural Health Monitoring should be composed of two main components: Structural Performance Monitoring (SPM) and Structural Safety Evaluation (SSE). As an example to illustrate how the WASHMS could be used for structural performance monitoring, the layout of the sensory system installed on the Tsing Ma Bridge is briefly described. To demonstrate the two broad approaches of structural safety evaluation - Structural Health Assessment and Damage Detection, three examples in the application of SHM information are presented. These three examples can be considered as pioneer works for the research and development of the structural diagnosis and prognosis tools required by the structural health monitoring for monitoring and evaluation applications.

Bioecological factors influencing women's alcohol consumption across the life span

Background Substantial changing trends in women’s alcohol consumption show increased proportions women drinking at risky/ high risk levels. Not confined to the younger female population, these increases are also occurring in older female age groups (aged 35 and over), posing a set of risks differing to those of their male counterparts. However, little research investigates the influences behind these changing trends. The current research examined multiple level influences (i.e. cultural, social and psychosocial on women’s drinking across a range of age groups. Methods Semi-structured telephone interviews were conducted with thirty-five women (aged 18-55) residing in Australia. Interview development was guided by an adaptation of Bronfenbrenner’s Bioecological Model of Development to assess multiple areas of influences from cultural through to psychosocial (i.e. intra-individual). Each interview took approximately 1 hour to complete. Findings Bronfenbrenner’s Bioecological Model could account for multiple-level factors impacting women’s drinking with multidirectional influences interacting across each level. Cultural influences included gender roles and national identity. Exosystem influences (e.g. infrastructure, legislation, and media) and microsystem influences (e.g. drinking context, family, partner and peer influence) were clearly identified as impacting drinking behaviours. Finally, at the psychosocial level, attitudes and expectations around the disinhibiting effects of alcohol and social facilitation emerged as key influences. Discussion The outcomes indicated the importance of these influences as women’s alcohol-related attitudes and behaviours changed across a woman’s life span and across age cohorts. Future research will build on these initial findings in order to underpin targeted interventions of the key factors influencing women’s drinking.

Exploring cultural, social and psychosocial influences on women's drinking across the life span

Background Changing trends in women's alcohol consumption have demonstrated that women, in both younger and older cohorts, are drinking at increased levels than previously. However, little research investigates these changing trends or the influences behind them. Aims The current research aims to identify influences on women's drinking across a range of age groups, with a focus on multiple level influences (i.e. cultural, social and psychosocial). Methods One hour semi-structured telephone interviews were conducted, in 2011, with 35 women (aged 18-55) residing in Australia. Interview development was guided by an adaptation of Bronfenbrenner's Bioecological Model of Development (BBMD) to assess multiple areas of influences from cultural through to psychosocial. Results Interview findings highlighted the existence of multiple levels of influence on women’s drinking and thus provided support for the BBMD framework. Cultural influences identified related to gender roles and national identity. Exosystem influences (e.g. legislation, infrastructure, and media) and Microsystem influences (e.g. immediate social networks) were also identified. A range of psychosocial factors, such as identity, normative influence and attitude were also found as influencing drinking behaviours. Finally, changes across a woman’s life span, and intergenerational differences, were Chronosystem constructs that also emerged as key influences. Discussion and conclusions This study has provided an in-depth understanding into the key factors, occurring across multiple levels of influence, impacting upon women's drinking across younger and older cohorts. The findings also highlight changes in alcohol-related attitudes and behaviours across a life span and across generations. Future research should extend upon these findings based on larger, quantitative studies based on representative samples. The findings do provide key insights into the influences that need to be addressed within targeted interventions.

Multiscale features and information extraction of online strain for long-span bridges

The strain data acquired from structural health monitoring (SHM) systems play an important role in the state monitoring and damage identification of bridges. Due to the environmental complexity of civil structures, a better understanding of the actual strain data will help filling the gap between theoretical/laboratorial results and practical application. In the study, the multi-scale features of strain response are first revealed after abundant investigations on the actual data from two typical long-span bridges. Results show that, strain types at the three typical temporal scales of 10^5, 10^2 and 10^0 sec are caused by temperature change, trains and heavy trucks, and have their respective cut-off frequency in the order of 10^-2, 10^-1 and 10^0 Hz. Multi-resolution analysis and wavelet shrinkage are applied for separating and extracting these strain types. During the above process, two methods for determining thresholds are introduced. The excellent ability of wavelet transform on simultaneously time-frequency analysis leads to an effective information extraction. After extraction, the strain data will be compressed at an attractive ratio. This research may contribute to a further understanding of actual strain data of long-span bridges; also, the proposed extracting methodology is applicable on actual SHM systems.