Rollover instability of precast girders subjected to wind load

Abstract

The use of longer and deeper precast concrete girders has created concern regarding their rollover instability, particularly during construction. Current design and construction specifications do not provide any specific guidelines that can be used to evaluate the rollover instability of a girder. Therefore, analytical and simplified numerical studies were performed to evaluate the critical wind load, lateral displacement and rotational angle that would induce rollover instability of a girder supported on an elastomeric bearing pad. The influence of the length and section properties of the girder on rollover instability was also investigated. The analytical method proposed in this study can be effectively used for evaluating the lateral behaviour and rollover instability of bridge girders and can also provide management values for securing the lateral stability of girders. The paper also provides a worked problem for a long-span typical European girder to determine critical values with application of the proposed method.

Rollover stability of precast concrete beams supported by elastomeric bearing pads

“…To represent the nonlinear behavior in compression of the bearing pad, a grillage model with nonlinear springs attached at nodes was developed, as in Lee et al [5]. These springs do not carry tension.…”

“…Thus, when the beam reaches great twist rotation, the grillage model can account for the loss of contact between the beam and pad (lift-off effect). This model was utilized coupled with numerical beam model to perform the geometrically nonlinear analysis, [5], which enables to obtain the load versus lateral displacement response of the beam and consequently establish a load level at which rollover occurs. Besides, the grillage model alone enables to determine the secant rotational stiffness of the pad for large rotations correspondent to the rotations of the beam at the time of instability.…”

“…Furthermore, the use of high strength materials allows the design of more slender beams, which minimize weight for all stages of construction. However, they become more susceptible to rollover instability when exclusively supported by bearing pads without any lateral bracing, in which the stability of the element is mainly ensured by the rotational stiffness of the bearing pad, [1]- [5]. Structural failures caused by the rollover of precast beams supported by bearing pads are not a new problem in bridge construction.…”

Experimental and Measurement Methods for the Small-Scale Model Testing of Lateral and Torsional Stability

“…The lateral and torsional stability is the main issue for the safety of structures and users from the stages of design to construction in the field of architectural and civil engineering (Kalkan 2014;Hurff and Kahn 2012;Lee 2012a, b;Lee et al 2016;Kim et al 2016;Hou and Song 2016;Petrone et al 2016;Ramin and Fereidoonfar 2015;Srikar et al 2016). Analytical investigations into the lateral and torsional stability have been performed to develop a classical stability theory based on the steel structural members (Horne 1954;Salvadori 1955;Timoshenko 1956;Timoshenko and Gere 1961).…”

Estudo do comportamento de almofadas elastoméricas sob vigas pré-moldadas e análise da estabilidade lateral após a montagem

“…Fluxograma para determinação do peso e dos deslocamentos críticos Fonte: Adaptado deLee (2017) Vale ressaltar que as análises deLee et al (2017) e Lee (2017) não fazem uma comparação dos valores obtidos pelos modelos com valores experimentais encontrados na literatura. Lee et al (2017) faz uma comparação entre três modelos numéricos, um formado por elementos de barras, outro por elementos de casca e o terceiro por elementos sólidos, porém isso não significa que o modelo adotado seja condizente com os valores reais esperados.…”