TY - JOUR

T1 - Lifetime Deflections of Long-Span Bridges under Dynamic and Growing Traffic Loads

AU - Lu, Naiwei

AU - Beer, Michael

AU - Noori, Mohammad

AU - Liu, Yang

N1 - Funding information: This work was supported by the National Basic Research Program (973 program) of China (Grant 2015CB057705), the National Science Foundation of China (Grant 51378081), and the Key Laboratory of Bridge Engineering Safety Control by Department of Education in Changsha University of Science and Technology (Grant 16KD03).

PY - 2017/11

Y1 - 2017/11

N2 - Steady traffic growth may pose a safety hazard to in-service bridges, especially long-span bridges subjected to the simultaneous presence of multiple heavy-duty trucks. This study presents a methodology for evaluating the statistical extrapolation of traffic-load effects on long-span bridges. As part of the contributions advancing the state of the art, this study addresses several challenging issues, including traffic growth, and the resulting dynamic impact, and actual traffic patterns. The nonstationarity of the traffic-load effects due to traffic growth is considered in a series system compounded by several interval traffic models. The dynamic impacts of traffic loads were simulated by a traffic-bridge-coupled vibration system, and the statistical characteristics were captured using a level-crossing model. The actual traffic pattern was simulated by stochastic traffic flows on the basis of the statistics of the weigh-in-motion measurements of a highway bridge. Two numerical examples show the ability of the interval-traffic-growth model to capture the nonstationarity of the growing traffic loads. In addition, a case study of a long-span suspension bridge shows the effectiveness of implementing the proposed methodology for the statistical extrapolation of the maximum deflection. The numerical results of the case study also reveal that the degradation of road-roughness conditions leads to more level crossings but also results in a slight increase in the extrapolation of the deflection. However, traffic growth results in rapid increases in both the extrapolated deflection and the probability of exceedance of the deflection limit.

AB - Steady traffic growth may pose a safety hazard to in-service bridges, especially long-span bridges subjected to the simultaneous presence of multiple heavy-duty trucks. This study presents a methodology for evaluating the statistical extrapolation of traffic-load effects on long-span bridges. As part of the contributions advancing the state of the art, this study addresses several challenging issues, including traffic growth, and the resulting dynamic impact, and actual traffic patterns. The nonstationarity of the traffic-load effects due to traffic growth is considered in a series system compounded by several interval traffic models. The dynamic impacts of traffic loads were simulated by a traffic-bridge-coupled vibration system, and the statistical characteristics were captured using a level-crossing model. The actual traffic pattern was simulated by stochastic traffic flows on the basis of the statistics of the weigh-in-motion measurements of a highway bridge. Two numerical examples show the ability of the interval-traffic-growth model to capture the nonstationarity of the growing traffic loads. In addition, a case study of a long-span suspension bridge shows the effectiveness of implementing the proposed methodology for the statistical extrapolation of the maximum deflection. The numerical results of the case study also reveal that the degradation of road-roughness conditions leads to more level crossings but also results in a slight increase in the extrapolation of the deflection. However, traffic growth results in rapid increases in both the extrapolated deflection and the probability of exceedance of the deflection limit.

KW - Deflection

KW - Level-crossing

KW - Long-span bridge

KW - Road-roughness condition

KW - Traffic growth

KW - Traffic load

KW - Vehicle-bridge interaction

UR - http://www.scopus.com/inward/record.url?scp=85028312987&partnerID=8YFLogxK

U2 - 10.1061/(ASCE)BE.1943-5592.0001125

DO - 10.1061/(ASCE)BE.1943-5592.0001125

M3 - Article

AN - SCOPUS:85028312987

VL - 22

JO - Journal of Bridge Engineering

JF - Journal of Bridge Engineering

SN - 1084-0702

IS - 11

M1 - 04017086

ER -