Estimation of Fatigue Life of Long-Span Bridge by Considering Vehicle-Bridge Coupled Vibration
To estimate the fatigue life of long-span steel bridge more accurately, this paper proposes a method for estimating the fatigue life of long-span bridges by considering vehicle-bridge coupled vibration. Firstly, the universal equation of vehicle-bridge vibration is derived based on triaxial standard multi-scale model of fatigue vehicle and bridge, and relevant program for vehicle-bridge coupled vibration is programmed. Secondly, a method for estimating the fatigue life of long-span steel bridge is proposed based on fracture mechanics theories, and the analysis process is expounded in details. Finally, the method for estimating fatigue life proposed in this paper is verified by taking a double pylon cable- stayed bridge with orthotropic steel bridge deck slab as an example.
Fatigue failure of welded vertical members of a steel truss bridge
Abstract This paper describes the analysis of the collapse of a steel truss motorway bridge. The cause of the failure was fatigue crack initiation and propagation in a welded vertical member caused by insufficient weld penetration.
The influence of daytime inactivity and nighttime restlessness on cancer-related fatigue.
PURPOSE/OBJECTIVES
To identify indicators involving circadian activity/rest cycles associated with higher levels of cancer-related fatigue (CRF) during the first three chemotherapy cycles after surgery for stage I/II breast cancer.


DESIGN
Prospective, descriptive, repeated measures.


SETTING
Midwestern oncology clinics and subjects' homes.


SAMPLE
72 women, ages 33-69 and free of unstable chronic illnesses, entered the study. Complete data were obtained from 30-47 subjects at each time.


METHODS
CRF was measured using the Piper Fatigue Scale at the start and midpoint of each chemotherapy cycle. Circadian activity/rest indicators were obtained using Mini-Motionlogger wrist actigraphs for 96 hours at the start of each treatment and for 72 hours at the midpoint of each chemotherapy cycle.


MAIN RESEARCH VARIABLES
Fatigue and circadian activity/rest indicators.


FINDINGS
Women who were less active and had increased night awakenings reported higher CRF levels at all three cycle midpoints, with the strongest association being number of night awakenings. During the third chemotherapy cycle, women who were less active during the day, took more naps, and spent more time resting during a 24-hour period experienced higher CRF.


CONCLUSIONS
Women whose sleep is disrupted at cycle midpoints are at risk for CRF. The cumulative effects of less daytime activity, more daytime sleep, and night awakenings are associated with higher CRF levels.


IMPLICATIONS FOR NURSING PRACTICE
Assessment of CRF and night awakenings at the midpoints of each chemotherapy cycle and development of nursing interventions to promote daytime activity and nighttime rest are key to managing fatigue and preventing loss of biologic rhythmicity.