Journal of Performance of Constructed Facilities

Extensive investigation of rapid-repair materials is of utmost importance in limiting the impact of repairs on vehicles traveling on bridges as well as in selecting suitable materials with acceptable mechanical properties and durability requirements. The objective of this study was to evaluate eight commercial cementitious rapid-repair materials for application to concrete bridge decks in Utah. A robust laboratory study to quantify mechanical performance and durability was been conducted, accompanied by evaluation of field performance. More than 450 specimens were prepared according to manufacturer recommendations and tested at ages of 4 h, 24 h, 7 days, and 28 days to measure their setting time, compressive and splitting tensile strength, elastic modulus, autogenous and drying shrinkage, restrained ring shrinkage, surface resistivity, and slant/shear bond strength. To evaluate the field performance of the materials, repair patches on the SR-193 bridge over US-89 in Layton, Utah, were inspected three times over a one-year period and crack developments on these patches were recorded. The purpose of the study was to identify the most influential factors in the success or failure of deck repair materials and to determine which tests are most helpful in the qualification of deck repair materials. The results will assist transportation officials, such as state departments of transportation (DOTs), in identification and qualification of materials to support successful and long-lasting bridge deck repairs.

An innovative sacrificial system consisting of hollow metal tubes as the energy-absorbing core was analyzed through three-dimensional (3D) finite-element analysis. The Johnson-Cook (J-C) plasticity model along with the J-C failure criterion were incorporated to model metallic parts under high-strain-rate loading, whereas the concrete damage plasticity (CDP) model was used to predict the behavior of concrete. Dynamic increase factors (DIFs) were used for concrete to understand the effect of high-strain-rate conditions. Finally, blast resistance performance of a square RC panel with dimension and thickness equals to 1,250 and 225 mm, respectively, with or without an innovative sacrificial system was analyzed under blast loading. From numerical simulation results, it is observed that sacrificial systems with thin sections of hollow metallic tubes performed better than thick sections irrespective of the same weight of the sacrificial system. Further, discussion was reported for the energy-dissipation curve of the system, and it is useful in defining the efficiency of the sacrificial system under blast loading.

Several modes of bridge distress related to interactions with approach roadways have been observed in Oklahoma through routine maintenance inspections. Upon closer review it was found out that there are two main mechanisms for a category of distress that includes bearings tilting, anchor bolts bending or shearing, concrete slope walls cracking, and girders pushing against the backwall. One of these mechanisms is the lateral movement of approach embankments. This movement tends to happen early in the life of a bridge and pushes the abutment toward the bridge and closes the bridge expansion joints. The other mechanism is the pressure from rigid approach pavements due to closed or nonexisting joints on pavements. The pavement pressure exerted on the bridge deck also closes the expansion joints. This paper focuses on the lateral movements of approach embankments. As a part of this research an extensive instrumentation and monitoring program was undertaken on a five-span bridge in Ada, Oklahoma, showing the characteristic signs of this distress. Through review of routine inspection reports and analysis of recorded data from installed instruments; a rehabilitation plan was developed and implemented. Following the rehabilitation, the instruments were monitored for an additional 3.5 years to verify the repairs were successful. Through this research it was found that if lateral embankment movement is the mechanism of distress, a successful rehabilitation plan can be implemented once lateral movement has stopped. The rehabilitation involved installing new bridge expansion joints and changing some of the girder end conditions for the monitored bridge. As a result of this research the Oklahoma Department of Transportation expanded their bridge inspection protocol to identify these two mechanisms for this category of bridge distress.

Collapse is one of the most dangerous aspects of drilling–blasting construction in highway tunnels. To accurately control tunnel-collapse risk, a multistate dynamic Bayesian network (DBN) evaluation method for highway tunnel collapse based on parameter learning was proposed. First, by analyzing the risk mechanism of tunnel construction, the initial BN model was established based on the causal relationship between risk factors and construction risk in hydrogeological conditions, construction technology, and construction management. Next, the construction process was discretized into finite time slices. In consideration of the fuzzy uncertainty of nodes, node polymorphism was introduced to construct a multistate DBN. Then, 50 typical tunnel-collapse cases were taken as sample data, and the conditional probability distribution of initial BN was derived using parameter learning based on the expectation-maximization (EM) algorithm. Using DBN reasoning and sensitivity analysis, the dynamic risk probability and the dominant factors of tunnel collapse were predicted. Finally, the DBN model was fed back with the measured cumulative values and velocity of the crown settlement, which updated the dynamic risk probability assessment results. In analyzing the collapse probability of Jinzhupa tunnel passing through the angular unconformity contact zone as an example, the results demonstrated that dynamic risk assessment results combined with monitoring data could better reflect the reality of construction contingencies, providing real-time risk management guidance.