Study on Control System for Live Load and Live Load Effects on Bridges. Highway IDEA Program;Final rept

摘要

The objective of the study is to develop an integrated system for monitoring live load and verifying live load carrying capacity of highway bridges. The proposed approach is focused on the control of various parameters including: truck weight (axle weights and axle spacing), truck load distribution on bridge girders, dynamic load, as well as strain, stress and deflection of bridge components. This study involves experimental and analytical efforts. The major contributions include the improvement of field testing procedures for site-specific weight-in-motion measurement of trucks, component-specific measurement of fatigue load spectra, calculation of critical truck loads (illegal overloads), accumulated fatigue load spectra, measurement of deflection, measurement of the dynamic load effect and dynamic load factor. Derivation of reliability-based criteria for acceptability limits (truck weight, axle load, number of load cycles, deflection), elements of active control with on-site response to critical overload as determined by comparison with the developed reliability-based criteria (e.g. illegal truck, exceeded fatigue load limit), integration of truck weigh-in-motion with diagnostic testing (e.g. to verify load distribution factors) and proof load testing (to verify the minimum live load carrying capacity), derivation of reliability-based criteria for establishing proof load level for bridges.