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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-9 of 9 Abstracts search results
August 8, 2019
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.
July 1, 2019
When preparing ready-mix concrete for private applications, it is typically recommended that owners and contractors collaborate with suppliers and concrete specialists to understand the possibilities and limitations of concrete in their applications. Here, we describe a situation in which a homeowner took direct control over the exact specifications of concrete and admixtures, and ultimately resulted in an unsatisfactory concrete slab. The owner subsequently sued and settled with the concrete supplier outside of the court, which raises important questions regarding who maintains responsibility for concrete mixtures, their installation, and the final slab results. Suggestions are provided to help mitigate this problem.
The increase in litigations in the design and construction industry over the years has restrained professionals in many fields from proposing or implementing innovative solutions. Since the major beneficiary of the innovative solution implementation is the OWNER, it is essential that the owner is intimately involved in the design process, and is not only aware of the risks and benefits associated with the proposed innovative solution, but is also willing to provide a written consent in sharing the risks associated with the proposed solution. This paper presents a case history where innovative engineering solutions were proposed and implemented, with full participation of the owner in recognizing and sharing the risk associated with the proposed solutions.
The project involved the investigation of cracking and repair of the Guastavino Dome at the Cathedral of Saint John the Divine in New York City. The dome, designed and built in 1909 by Rafael Guastavino (Jr), has a 135ft (41M) span, is 155ft (47M) above the floor, and was constructed using his patented system of interlocking tiles and layers of mortar in 15 weeks. The dome was intended to be a temporary structure to last no more than ten (10) years when it was to be replaced by a high central tower. In the late 1960s, pieces of tile and mortar fell from the underside of the dome. As a result, the dome was rated to be unsafe and recommended for replacement. This paper briefly
summarizes the original design, the structural evaluation, the recommended innovative solutions, and the owner’s participation in implementing these solutions, to ensure the safety and prolonged life of the dome. The dome is fully
operational at present.
ASCE’s Forensic Engineering Division (FED) is focused on educating the engineering community on the professional practice of forensic engineering. These practice guidelines are applicable to a broad range of facility assessment, repair and rehabilitation programs. This paper focuses on the FED contributions to assessment and repair of existing structures, including Forensic Congresses and the Journal of Performance of Constructed Facilities. The work of the FED has improved quality and public safety in constructed facilities.
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.
Reinforced Concrete has been a material of choice and is the second most consumed material per capita in the world after water. The Indian Construction Industry is set to rise from a value of US$ 428.1 billion today to US$ 563.4 billion in 2020. Exponential growth in Indian concrete construction over the past 40 years has concurrently created very sizeable need as well as a market for repair-related activities.
William Wilson and Daniel Moser
This is a case study involving an aging parking structure that deteriorated to the point where the structural floor slab failed. The lines of responsibility between parties involved with owning, managing and repairing the existing, exposed structures are not always clear, based on contractual language. This case ended in litigation to determine who was responsible for repair costs when the structural slab reached the end of its service life, taking into account the root cause of the slab failure. In this case study, we review the field and background
information obtained for this case as well as the court interpretation of lines of responsibility and contract language regarding parking structure maintenance and normal wear and tear.
Pericles C. Stivaros
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.
Keith Kesner and Kevin Coll
Evaluation of an existing structure is a task commonly performed by licensed design professionals. An evaluation can be required by a façade inspection ordinance, as part of a due-diligence process prior to the purchase of a structure, or prior to the development of rehabilitation or repair measures. Each of these project types will have differences in the evaluation protocol and portion of the structure to be examined – but in each example, the licensed design professional is expected to provide a minimum “standard of care” to the client and to protect the public. Therefore, in developing the evaluation protocol, a critical question facing the licensed design professional is how much investigative effort is required to complete the evaluation and ensure the evaluation provides a minimum standard of care.
The standard of care for an evaluation of existing structures can broadly be defined as the level of effort that a reasonable and prudent licensed design professional would be expected to provide under similar circumstances. Given the range of structure types that can be encountered and the varying levels of damage and exposure conditions, determination of the scope of evaluation can be a difficult task for a licensed design professional. The following sections examine approaches used in industry codes and ordinances to help define a minimum standard of care for the evaluation of existing structures. Industry codes and ordinances to be examined will include the ACI 562-16 Code for Assessment, Repair and Rehabilitation of Existing Structural Concrete, FHWA bridge inspection requirements and building façade inspection standards and ordinances. Based upon these documents, items to be considered in establishing a “Standard of Care” in the evaluation of existing structures will be summarized.
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