RC Bridge Decks Under Pulsating and Moving Load

2008

ACT

The shear fatigue behavior of cracked concrete interface was experimentally investigated on a single crack plane to quantify the degree of deterioration per load cycle. A simple experimental setup was used, in which a finite lateral stiffness was provided to the crack interface by using unbonded steel bars. The effects of loading amplitude, loading pattern and water exposure were examined. Time-dependent behavior of shear transfer under sustained shear load was also investigated. The shear fatigue response of cracked concrete interface was found to be characterized by gradual increments of shear slip and dilation and majority of the incremental displacements to occur in the first few cycles. The degree of deterioration was found to be highly sensitive to the load amplitude level and loading pattern. The relative extent of deterioration in the case of reversed cyclic loading was much larger than that of single-sided fatigue loading. Worse yet, the downward flow of water through the crack interface was found to accelerate the shear fatigue degradation. The experimental results are summarized and a simplified phenomenological model is proposed to quantify the degeneration of shear stiffness in terms of intrinsic accumulated normalized slip with respect to crack opening.

Section: Response Under Reversed Cyclic Loadingmentioning

confidence: 99%

Shear Fatigue Response of Cracked Concrete Interface

Gebreyouhannes

Kishi

2008

ACT

“…10, is particularly noteworthy. Under fixed-point loading, the fatigue life diagram (S-N diagram) is quite similar to that of RC beams (Kakuta and Fujita 1982) but with wheel-type loading the slab life-cycle is considerably degraded (Matsui, et al 1984, 1987, Perdikaris, et al 1988.…”

Section: Computed Fatigue Lifementioning

confidence: 99%

Three-Dimensional Fatigue Simulation of RC Slabs under Traveling Wheel-Type Loads

Gebreyouhannes

Mishima

et al. 2006

ACT

A direct path-integral scheme with fatigue constitutive models for concrete tension, compression and rough crack shear is used to predict the life-cycle of RC slabs. The three-dimensional fatigue analysis successfully predicts the characteristic mode of failure under moving loads as well as in the case of fixed-point pulsation in shear. Importantly, drastically shortened fatigue life under traveling wheel-type loads is mechanically demonstrated by implementing a constitutive model of cracked concrete using a direct path-integral method of fatigue damage simulation. A sensitivity study is carried out to clarify the influence of shear transfer decay and compression fatigue on RC slab performance. The effect of boundary conditions on fatigue life is also investigated.

“…For bridge decks, certain research groups installed wheeltype moving-load machines and directly analyzed fatigue failure mechanisms (Matsui 1987;Pedikaris and Beim 1989). Based upon these advanced studies, S-N diagrams of RC decks under high-cycle moving loads have been developed.…”

Section: Introductionmentioning

confidence: 99%

Pseudo-Cracking Approach to Fatigue life Assessment of RC Bridge Decks in Service

Fujiyama

Tang

et al. 2013

ACT

This paper presents a numerical scheme to estimate a residual fatigue life of damaged RC bridge decks by means of the pseudo-cracking method proposed, which converts crack inspection data into the on-site mechanistic damage of structural concrete. First, crack information, which can be obtained through a simple visual inspection at site, is transformed to equivalent strain fields upon a finite element discretization, and an equivalent damage state is numerically reproduced. Then, the proposed system simulates subsequent responses to assess the residual fatigue life despite the initial cause of the cracks. The methodology proposed in this study was examined by re-producing several inspection processes computationally, and the numbers of traffic load passages at failure is verified without using the past loading history. For engineering verification, the fatigue-loading experiment of RC slabs, which was taken from a bridge subjected to the real traffic loads, are targeted to be simulated by the pseudo-cracking approach. Sensitivity analyses are also conducted to compute the S-N diagram of the damaged slabs in the five deterioration grades specified by the JSCE maintenance code, and the quantitative results are found to approximately match the specified recommendation. This study indicates that the proposed approach is capable of leading crack strain fields of RC slabs to remaining life-span simulation of damaged RC for the case of low intensity and high cycle fatigue actions.