Increasingly, the Construction Industry is being dramatically impacted globally by internal and external forces. These influences range from acute labor and skill shortages, demographic and urbanization shifts, as well as, the Industry’s conversion from analog-based processes to digital workflows. This presentation will overview ten significant trends which are uniquely affecting the Construction Industry, creating both new challenges and opportunities, while transforming the Construction Industry.
The ACI 562-16 Repair Code is primarily intended for the Licensed Design Professional for providing the requirements necessary for assessing and designing repairs and rehabilitation of existing concrete structures.
In June 2016, ACI published ACI 562-16,” Code Requirements for Assessment, Repair and Rehabilitation of Existing Concrete Structures and Commentary”. ACI 562-16 replaces ACI 562-13 as a standard for the repair of existing concrete structures. Significant changes to ACI 562-16 include improvements in terminology for consistency with ISO, ASCE and other documents, inclusion of requirements for level of repair based upon extent of damage present, and revisions to the interface bond provisions. The video will describe the concrete repair code, focusing on key changes made to the code and describe how the code is to be used on concrete repair projects.
Alkali-Silica Reaction (ASR) can cause significant damage to concrete structures including bridges, roadways, airport runways, and nuclear power plants. When reactive aggregates are included in a mix, the presence of moisture initiates a reaction between the alkaline cement paste and reactive amorphous silica. The result is a gel that continues to dilate, which may cause cracks in the concrete mass. A research program was undertaken at the University of Toronto to investigate the effects of ASR on large-scale and small-scale concrete specimens. Several specimens were constructed using reactive (ASR) concrete and non-reactive (regular) concrete, and their short-term and long-term structural and mechanical behavior were compared. In this presentation, we will discuss the results of the research program, will offer best practices to minimize the risk of ASR in concrete during placement, and will propose several strategies for repair of structures that have been degraded due to ASR.
The application of nondestructive testing and evaluation for detecting existing defects and anomalies in concrete structures will be presented. Proper inspection and assessment is an integral part of a successful repair and rehabilitation. A well-defined inspection will help asset owners and their consultants in identifying the location and extent of existing defects, and enabling them in selecting proper repair materials and optimizing the area that needs rehabilitation. Moreover, NDT methods can help identify potential defects that are not visible to the naked eye, such as early-stage delamination, corrosion, and other durability related issues. In this presentation, several cases in Canada will be demonstrated, where the results of nondestructive testing and evaluation have been used to help consultants and contractors with cost-effective and reliable repair planning. Applications of ground penetrating radar, ultrasonic pulse echo tomography, seismic tomography, will be discussed.
Arrowhead Stadium originally opened in 1972 and is known to be the home to the Super Bowl Champions Kansas City Chiefs. Renovations of the stadium completed in 2010 included adding luxury suites on the club level of the stadium. This meant that the upper seating bowl not only had to seat more than 34,000 Chief fans but also act as a "roof" for the new luxury suites. The upper seating bowl comprises L-shaped precast concrete seating risers spanning from cast-in-place concrete raker beams and is divided by sixteen expansion joints. In 2018, the planning for the upper seating bowl waterproofing program began. The goal for the repair project was to implement waterproofing upgrades to protect the concrete for the next 10 years. To add to the challenge of a large-scale waterproofing and structural repair project, the construction efforts had to include coordination with simultaneous seat replacement to be completed in a single off-season.
Matching concrete sounds simple, but there are many factors that affect color, texture, and aesthetics. There is often a challenge with using modern cementitious materials for matching older and historically manufactured cements. Whether your project is historic or contemporary, this presentation will outline materials and methodology that are important to understand when concrete matching is important. With many mid-century buildings coming of repair age, this is a critical time for understanding these concepts. The presentation will include the fundamentals of concrete materials, how cementitious materials affect concrete color, how to use color measurement technology in developing a color match mix design, how aggregate exposure affects aesthetic perception, and other helpful tips when it comes to matching concrete for durable and aesthetic results. Regionally available materials will vary, but the methodology for color matching durable repairs is fundamentally the same.
This presentation looks at buildings that are new or being rehabilitated and the impact on making buildings more energy efficient. Starting with the 2012 IBC, and specifically the 2012 IECC portion of the building code and newer versions, the presentation will look at three aspects of the building envelope: Water Resistance, Air Leakage, and Moisture Transmission. It will then compare to identical buildings, the first built in 2000 and the second constructed in 2020. Illustrations and calculations will show how controlling air leakage can have an enormous impact on the service life of the structure, initial cost of construction, and on-going operations. Lastly, the presentation will look at how incorporating simple additions during the repair/rehabilitation process can have a positive impact on the environment as well as the building owner and the building’s constituents.
Arlington Memorial Bridge is a reinforced concrete spandrel arch bridge that connects Washington, DC and Virginia across the Potomac River. After over 85 years in service, the bridge started exhibiting signs of deterioration, including reinforcement corrosion. As part of a major rehabilitation effort to extend the bridge’s service life, targeted cathodic protection (CP) systems were installed in the arch cross-walls, floors, and under arches to mitigate and prevent corrosion. The implemented CP system consisted of galvanic and two-stage anodes to mitigate corrosion. Galvanic anodes were installed in the repair areas to prevent the ring anode affect and ensure a durable concrete repair. The two-stage anodes were installed in areas of concrete which were actively corroding without signs of concrete deterioration.
What happens when a building owner calls with leaks into a building they just finished? After verifying whether they want to file a lawsuit or not, the course of action is important. An investigation and preliminary testing are typically recommended to understand the original design and the quality and consistency of the construction. Design of remedial repairs and a pilot repair program followed by retesting to confirm results. How extensive are the failures and how invasive do the repairs need to be? Costs? What materials were used and were they compatible? Public perception and developer/owner reputation are important. The occupants have just moved in. Higher expectation of successful repairs. Can we involve the original design and construction team? These are just a few of the issues that need to be faced early in this process. One must communicate often and clearly with the owner and rest of the project team in order to manage expectations, costs and construction quality control.
