Following an over-height truck impact, Carbon Fiber Reinforced Polymer (CFRP) fabric was used to retrofit the exterior girder in a four-span Reinforced Concrete Deck on Girder (RCDG) Bridge on route KY 562 that passes over Interstate 71 in Gallatin County, Kentucky. The impacted span (Span 3) traverses the two northbound lanes of Interstate 71. While the initial retrofit was completed in May 2015, a second impact in September 2018 damaged all four girders in Span 3. The previously retrofitted exterior girder (Girder 4) suffered the brunt of the impact, with all steel rebars in the bottom layer being severed. Damage to Girders 1, 2, and 3 was minor and none of the bars were damaged. A two-stage approach for the containment and repair of the damaged girders following an over-height truck impact was implemented when retrofitting the bridge. The repair and strengthening of all the girders using CFRP fabric was the economical option compared to the alternative option of replacing the RCDG bridge. The initial CFRP retrofit was found to have failed in local debonding around the impact location. The CFRP retrofit material that was not immediately near the impact location was found to be well bonded to the concrete. The removal of this material and subsequent surface preparation for the new retrofit was time consuming and challenging due to traffic constraints. In Girder 4 all but one of the main rebars were replaced by removing the damaged sections and installing straight rebars connected to the existing rebars with couplers. One of the rebars could not be replaced. A heavy CFRP unidirectional fabric, having a capacity of 534 kN (120,000 lbs.) per 305 mm (1 ft.) width of fabric, was selected for the flexural strengthening and deployed to replace the loss in load carrying capacity. A lighter unidirectional CFRP fabric was selected for anchoring and shear strengthening of all the girders, and to serve as containment of crushed concrete in the event of future over-height impacts. The retrofit with spliced steel rebars and CFRP fabric proved to be an economical alternative to bridge replacement.

This paper discusses the structural assessment and repair of a waterfront concrete pier. This paper also discusses the responsibilities of the construction team through the investigation and repair process. The apron around the pier is an exposed concrete deck supported on steel beams and concrete caissons. The concrete apron exhibited various deteriorated conditions, including cracking and spalling. The pier owner requested a structural condition survey of the pier apron to determine the extent of the damage and to develop a repair program.

The design team proposed an investigation and repair program in accordance with various industry standards, including ACI 357, ACI 562, and ACI 364.1R. The challenge of this project was the limited budget and time allocated by the owner to perform the investigation and repair. As a result, the investigation was limited to visual observations only, and the repairs were restricted to repairing unsafe conditions only. Despite the investigation and repair construction limitations, the design team work around the needs and budgets of the owner and managed to restore the structure to a safe condition. However, the effects of insufficient evaluation of the structure before rehabilitation, had an adverse effect on the project schedule and extent of repairs performed. Also, due to the project budget limitations, the responsibilities of the design team were challenged.

The responsibilities for parties involved in a repair project may be significantly different than those traditionally encountered in new concrete construction. The new ACI 562 Code Requirements for Assessment, Repair and Rehabilitation of Concrete Buildings and corresponding ACI 563 Specifications for Repair of Concrete in Buildings identify requirements for the Licensed Design Professional and the contractor’s Specialty Engineer during repair programs. Differing lines of authority in repair are presented through industry practice recommendations and case studies, along with identification of industry needs, informing parties engaged in concrete evaluation and repair projects.

Evaluating and repairing concrete structures often extends the lines of responsibility of the Engineer of Record (EOR) beyond those traditionally encountered in new construction. Case studies are presented to illustrate how responsibility often broadens during major project stages: a) evaluating existing structures; b) establishing feasibility measures for repairing or strengthening existing structures; and c) implementing repair/strengthening of existing structures. Differing lines of responsibility are identified and compared to those customarily encountered in new concrete construction. Reference is made to the new Code Requirements for Assessment, Repair & Rehabilitation of Existing Concrete Structures (ACI 562-16) and industry practice standards, identifying industry needs for parties engaged in concrete evaluation and repair projects.

A successful concrete repair project requires a close coordination of efforts between the three major parties involved: the owner, the licensed design professional (LDP), and the contractor. Lack of coordination and clear understanding of the professional and contractual responsibilities, as well as the expectations, of each party involved in a concrete repair project, could result in long legal disputes to attempt to sort out the responsibilities of each party. The greatest victim of the dispute is usually the structure itself. The American Concrete Institute (ACI) has led the effort to develop responsibility guidelines in concrete construction. ACI 132 identifies and suggests the allocation of responsibilities to various parties involved in concrete construction. ACI 132 document is applicable to general concrete construction, and it does not consider the particularities of evaluating and repairing existing concrete structures. ACI 562 provides minimum requirements for assessment, repair and rehabilitation of existing distressed concrete structures, including a discussion on the responsibilities of the licensed design professional for the evaluation and repair of concrete structures. This paper discusses the responsibilities of the licensed design professional, the contractor, and the owner through a repair case study. The paper demonstrates the need to expand ACI 132 and/or ACI 562 to include responsibility guidelines for concrete repair projects.