Safety assessment of in‐service reinforced concrete T‐girders of bridge decks

Abstract

Reinforced concrete bridges located in coastal environment are known to undergo structural degradation due to chloride‐induced corrosion of reinforcement. In this paper, reliability‐based methodologies have been formulated for safety assessment of in‐service reinforced concrete T‐girders against shear and cracking limit states. The proposed methodologies incorporate the following features: (a) gain in concrete compressive strength with time, (b) the time‐dependent diffusion of chlorides into cover concrete, (c) the chloride‐induced corrosion of both stirrups and main rebar of pitting type, (d) the corrosion current variation along the span, (e) the reduction in yield strength of stirrups after it starts corroding, and (f) corrosion crack formation due to the accumulation of the corrosion products. The system reliability concept is embedded in the framework of Monte Carlo simulation, for estimating the time‐variant failure probabilities. The usefulness of the methodology is demonstrated on a typical in‐service Chennai flyover, designed according to MORTH. The girder fails to meet the target reliability index consideration in the case of shear limit state and also fails the required serviceability criteria even before the end of 50 years. This example brings out the need to consider time‐variant reliability considerations at the design stage itself.

Reliability based service life prediction of bridges in Indian coastal region

“…This research led to the conclusion that Portland pozzolanic concrete is structurally more reliable than OPC concrete for bridge girders. Yogalakshmi et al 7 further extended the structural reliability of RC bridge girders over the service life in terms of corrosion cracking and computed reliability index.…”

“…Many experimental and analytical studies are available for estimating the structural safety and service life of structures subjected to chloride-induced rebar corrosion. [3][4][5][6][7][8] Corrosion of rebars cause splitting cracks in concrete, spalling of cover, and structural damage leading to a reduction in the service life of the bridge. Two types of rebar corrosion i.e., uniform and pitting are commonly observed.…”

Time-Dependent Reliability Assessment Method for RC Simply Supported T-Beam Bridges Based on Lateral Load Distribution Influenced by Reinforcement Corrosion

“…Furthermore, the time-dependent bearing capacity was predicted based on the degradation model, which considered reinforcement corrosion, concrete, and structural deterioration as the main influencing factors [18]. In addition, time-dependent reliability and life prediction methodologies for bridge components and systems were developed by considering the uncertainties of environmental factors and geometric dimensions [19][20][21]. The seismic performance assessment of corroded reinforcement bridges was analyzed by the finite-element model and nonlinear material model [22].…”

Repair of reinforced concrete bridge columns subjected to chloride‐induced corrosion with ultra‐high performance fiber reinforced concrete

“…Particularly, existing RC bridges subjected to the risk of corrosion deserve careful consideration because this may have large negative impacts on safety, functionality, and resilience of the transportation network they belong to. Within this framework, special attention has been paid on the assessment of chloride-induced corrosion in RC bridges, [1][2][3][4][5] since the effects of the pitting corrosion that it causes can be more severe than those of the uniform corrosion due to carbonation. 6 In this perspective, apart from forecasting, monitoring, and assessing RC bridges subjected to corrosion, repair and retrofit are becoming relevant priorities in current transportation networks management policies.…”