Investigation of Likelihood of Cracking in Reinforced Concrete Bridge Decks

Abstract

One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. The cracks can be influenced by material characteristics, casting sequence, formwork, climate conditions, geometry, and time dependent factors. The cracking of bridge decks not only creates unsightly aesthetic condition but also greatly reduces durability. It leads to a loss of functionality, loss of stiffness, and ultimately loss of structural safety. This investigation consists of field, laboratory, and analytical phases. The experimental and field testing investigate the early age transverse cracking of bridge decks and evaluate the use of sealant materials. The research identifies suitable materials, for crack sealing, with an ability to span cracks of various widths and to achieve performance criteria such as penetration depth, bond strength, and elongation. This paper also analytically examines the effect of a wide range of parameters on the development of cracking such as the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits liveload deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. The deflection is found to be an important parameter to affect cracking. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented.

Evaluation of the Compatibility of Repair Materials for Concrete Structures

“…Delaminations often occur in bridge decks due to corrosion in the reinforcing bars causing tensile stresses to the concrete and flexural loading conditions inducing shear stresses along the top mat of reinforcement (Krauss and Rogalla 1996;ElSafty and Abdel-Mohti 2013). A typical bridge consists of vertical supports spanned by horizontal beams.…”

“…Corrosion of steel bars can lead to a concentration of internal stresses in the concrete and reduction in bond often resulting in further cracking and deterioration. Different types of concrete cracks are observed in concrete decks (Krauss and Rogalla 1996;ElSafty and Abdel-Mohti 2013;Ramseyer and Kang 2012;Soltani et al 2013;Labib et al 2013). These include vertical cracks which can be detected by visual inspection when there is no overlay and horizontal cracks, also called delaminations, which can cause a breaking-away of the concrete deck.…”

Field-Observed Cracking of Paired Lightweight and Normalweight Concrete Bridge Decks

“…A number of factors related to bridge design can contribute to bridge deck cracking (ElSafty and Abdel Mohti 2013). Restraint is typically caused by end conditions and the composite action between the bridge deck and the supporting members of the superstructure.…”

“…Restraint can also be provided by stay-in-place forms . Thicker bridge decks tend to have less cracking (TRB 2006;ElSafty and Abdel-Mohti 2013), although the relative stiffnesses of the bridge deck and the girders is an important factor in the propensity for a deck to experience cracking . The type of girder used in a bridge superstructure has been shown to influence cracking, with bridge decks of steel girder bridges often exhibiting more cracking than bridge decks supported by other types of girders due to stiffness (Perfetti et al 1985;Krauss and Rogalla 1996).…”

“…The type of phased construction and continuity between spans in bridges built with precast girders can have important consequences in bridge deck cracking (Sousa et al 2012). ElSafty and Abdel-Mohti (2013) found that deflection is an important parameter affecting cracking. Reinforcing steel characteristics (including bar size, spacing, cover, and other details) can affect the extent of bridge deck cracking as well as crack widths and patterns (Soltani et al 2013).…”