Document Type

Conference Proceeding

Publication Date

1-1-2024

Abstract

Constructing bridges using precast prestressed concrete girders is extremely popular because of their durability and ease of construction. Establishing continuity between precast girders has its advantages and has been employed in many projects. It causes the development of positive restraint moments at intermediate supports as a result of long-term effects such as creep, shrinkage and thermal gradients. Prestressed concrete girder end cracking occurs if the positive restraint moments exceed the girder’s cracking moment. In this study, the probability of girder end cracking in continuous prestressed concrete bridges is assessed using structural reliability concepts. This study focuses on two bridge configurations with different lengths and girder cross sections, which were assumed to be continuous over two spans. Design parameters such as dimensions, modulus of elasticity, modulus of rupture, area of prestressing steel and temperature gradient are first defined as random variables. A limit state function to assess the probability of girder end cracking is established based on the identified random variables for the serviceability limit state. The effects of creep, shrinkage, prestress, and temperature gradient were considered in the analyses. Monte Carlo simulations were then used to assess the probability of girder end cracking for an assumed girder age of 28 days. Results show that for this girder age, the probability of girder end cracking is high (68.2% – 91.8%); highlighting the vulnerability of prestressed concrete girder end cracking when used in continuous bridge spans as has been observed in the field. The vulnerability of girder ends to cracking is exacerbated by the fact that not the entire section is yet engaged in resisting restraint moments due to St. Venant’s principal.

Publication Source (Journal or Book title)

Bridge Maintenance, Safety, Management, Digitalization and Sustainability - Proceedings of the 12th International Conference on Bridge Maintenance, Safety and Management, IABMAS 2024

First Page

1817

Last Page

1824

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