On August 9, 2019, Tyson Foods' Holcomb, Kansas beef plant experienced the first large fire in the meat processing industry in nearly 20 years. The long-burning fire precipitated the collapse of a portion of the high roof over the mechanical mezzanine, which housed equipment for numerous critical plant processes. This took portions of the plant, the second largest in the United States, out of operation for months. The pressures of substantial business interruption costs, as well as the market consequences for cattle feeders from the Southern Plains region, necessitated a rapid response. This presentation highlights the investigation into the extent of damage to precast members, including visual inspection, nondestructive and laboratory evaluations, testing, simulation, and analyses. Based on this investigation, members were identified for repair or removal and replacement.
From the days of boiled Linseed oil, to the discovery of membrane forming cures, to the development of carbon dioxide injection; curing has evolved to accommodate the demands of the construction industry. This presentation will look back at the early standards developed by ASTM, contrasting them to the standards that are currently under consideration. There are many ways to cure concrete, this presentation will review the various product options framed in the context of weather. Lastly, the presentation will explore the various methods discussing the features and benefits of the common curing practices of today.
This session will describe the use of tensile pull-off (bond) testing for concrete repairs and bonded overlays. It will provide guidance on applications of the test, industry standards and guidelines, acceptance criteria, proper testing procedures, appropriate equipment, and interpretation and reporting of test results. Bond is important because it relates to structural requirements (e.g. for strengthening and structural repairs) and for durability requirements (e.g. for overlays and cosmetic repairs). Testing of bond is needed to verify that the specified bond requirements have been met and a satisfactory result has been obtained.
Using Unmanned Aerial Vehicles and Systems (aka UAVs aka Drones) continues to be a hot topic for engineers and designers. Within the past 10 years, we have seen technology change how we live, work, play and learn. These advances in technology have enabled humans to be more efficient as well as socially and environmentally conscious and connected. Advances in engineering technology and efficiency have expanded structural engineer’s roles in inspection services. This presentation will highlight drone utilization for exterior surveys and inspection, impact on the built environment, and how drones will continue to influence in the future. This includes areas that are too dangerous for humans or structures where rigging can be difficult or impossible as well as the cost benefits of using a drone. The presentation will also delve into the effectiveness and appropriate applications of drone usage, specifically for hands-on applications.
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.
After only six years of service, a 6-foot long narrow piece of concrete spalled off an exposed slab edge of a 680-foot tall high-rise in Texas, and fell 160 feet to the podium below. The spall was attributed to premature corrosion at the drip edge. The building featured approximately 9,200 feet of exposed slab edge over its height. Given the potential risk to safety and property of additional concrete spalls, the Owner requested forensic investigations, which (1) identified other areas with signs of similar distress and (2) determined the underlying problem of low reinforcement cover at the drip edge was pervasive. In response, repair options were developed to address the problem and restore intended durability. Given the building height, difficult exterior-only access, downtown environment, and post-tensioning anchors along the slab edge, the repair design and construction both had unique challenges to consider and overcome.
Industry questions related to moisture-related floor covering and coating failures will be answered by the presenter during a 1-hour webinar. Questions will come from ICRI members through a survey conducted prior to the webinar and PPT slides addressing the questions prepared by the presenter. Questions from webinar attendees will also be answered during the webinar.
Dallas City Hall and Plaza are recognized by many due to the opening scenes of Dallas, the television show. What is less known is that the structure is a significant early example of bonded post-tensioned concrete which was utilized throughout the superstructure and two-story parking garage constructed beneath the plaza. Opened in 1977, the parking garage is a two-way bonded post-tensioned concrete slab with unreinforced drop panels supported by flared circular concrete columns. The garage covers two city blocks, extends under two adjacent multi-lane streets, and supports mature landscaping, pool, fountain, and up to 11’-0” of soil. In 2017, several square feet of a drop panel fell from the structure and subsequent observations found multiple locations of drop panel and column capital failures. A structural investigation including destructive and non-destructive testing, and analysis of the existing structure was undertaken to determine the cause of the failures.
Shotcrete has been used widely for rehabilitation and retrofit of concrete structures. More and more large infrastructures, in particular, in the hydro power industry, is using shotcrete for major rehabilitation and retrofit. Recently, the US Army Corps of Engineers has been engaged in structural modifications to reinforced concrete draft tube exits from the turbines in the Ice Harbor Lock and Dam located on the Snake River, Washington. This presentation details the structural modification to the draft tube which was successfully completed using wet-mix shotcrete.
This update includes fall protection requirements for low slope roofs, façade access, and ladders as well as a timeline for compliance. This seminar not only addresses the recent 2017 updates to 29 CFR Part 1910 General Industry, but is an overview of all fall protection standards found in both Part 1910 for General Industry and Part 1926 Construction. The components of a Comprehensive Managed Fall Protection Program are also presented as well as specific requirements for the fall protection options available. Because many in the industry either do not understand the standards, are unaware of the available OSHA interpretations, or prefer not to spend money training their employees, misinformation is being spread. This seminar provides the truth about the required implementation of the updated fall protection standards and the standards that remain in place.