01340063

Component

Over the past couple decades there have been significant developments in availability of new materials and technologies suitable for civil infrastructure such as highway bridges. High performance steel (HPS) is one such a material that offers higher yield strength, enhanced weldability, and improved toughness. As a result of higher strength it can result in lighter and much more economical designs. However, live-load deflection (L/D) limitations of bridge design specifications negate the economical implementation of HPS. AASHTO Standard Specifications limit live load service deflection to L/800 for general bridges and to L/1000 for bridges that are used by pedestrians. These limits were originally founded to control undesirable structural or psychological effects due to bridge vibration. However the results of prior studies indicate that deflection and L/D limits do not necessarily address these objectives; and undesirable bridge vibration can be better controlled by other parameters of vibration such as acceleration, velocity, and frequency. Although AASHTO LRFD Bridge Specifications has made these limitations optional, there is not yet any method suggested by AASHTO to limit vibration. There are a few alternate design methods which have been developed to better address the serviceability and durability issues. However, these methods have not been adopted in part due to the practical limitations in their application but mostly due to the lack of consensuses. Therefore, there is a need to develop a more rational serviceability requirement in which vibration is limited by the use of other parameters of vibration beside deflection. To develop such a requirement, bridge vibrational behavior should be completely investigated considering different bridge characteristics and types of loading. This paper presents a summary of the previous studies on human response to the vibration and the structural performance due to vibration; and the effect of parameters such as span continuity and the excitation of higher modes due to different types of loading on bridge dynamic response. The analytical study employs 2-D Finite Element (FE) models to evaluate dynamic response of bridges under moving truck load.

01329018

11-3787

English

16p

2011

Transportation Research Board 90th Annual Meeting

DVD

Figures (7) ; References (13) ; Tables (5)

Bridge design; Deflection; Finite element method; Footbridges; Highway bridges; Live loads; Load and resistance factor design; Materials selection; Traffic loads; Vibration

AASHTO LRFD Bridge Design Specifications

Dynamic response (Structures); High performance steel; Truck loads

Bridges and other structures; Highways; Materials; I24: Design of Bridges and Retaining Walls

Transportation Research Board Annual Meeting 2011 Paper #11-3787

TRIS, TRB

Feb 17 2011 6:38PM