Application of live load model for design of long span cable bridges

Recently with the increasing number of long span cable bridges, new design guideline for long span cable stayed bridge and suspension bridges has been developed in Korea. This paper deals with the development and application of the live load model for long span cable bridges. New live load model was proposed based Weigh-In-Motion data and various traffic scenarios assuming traffic jam situations. WIM data in several locations in Korea were used in this study. New live load model consists of four-axle truck with total weight of 510 kN and uniformly distributed load which its magnitude decreased as the length of the effective influence line increases. Due to the complexity of cable bridge structures, the shape of the influence line may be intermittent or cusped. So partial loading on effective influence line may give larger effects than full loading. Different loaded lengths were considered based on one to ten percent of maximum value of the effective influence line. Section forces are calculated and compared for various members and sections in different locations according to the several cases of loaded length. Based on the results, new design guidelines for the application of live load model are proposed.