The presentation, through case studies, talks about emergency response services for structural issues encountered during construction of new design projects. Among other examples is an eleven story precast parking structure. The contractor observed significant diagonal faulted cracking of L-beams (supporting double-tee sections) near bearing locations, few days after pouring topping slab. In addition, inverted-tee girders were observed to be supported on cracked corbels at other locations. A quick turn around was required to mitigate any immediate life safety hazard posed by the structural distresses and buy time for thorough investigation, non-destructive testing, analyses, and repair design. Another example is a seven story precast parking structure. The structure was under construction and reportedly erected out of plumb. Poor concrete placing practices and poor weld detailing led to widespread cracking in multiple structural elements throughout the structure...
This presentation will look at how technology is used to perform condition assessments at height and in places with difficult access utilizing a virtual toolbox that includes a wide range of instruments and tools for non-destructive evaluation and testing, and a fleet of drones, each of which has a different use. The presentation will discuss how to use drones and tools at height; how the industry is using drones in new ways; and how some municipalities are changing policies to adapt, especially with regard to facade inspections.
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.
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.
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.
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.
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.
Richard Miller Treatment Plant is a 240 mgd cap. potable water treatment facility located in the California area of the Cincinnati, Ohio, US. After installing an advanced ultraviolet (UV) disinfection treatment system in 2013, GCWW became the largest water utility in North America to use UV light following sand filtration and granular activated carbon. The concrete filter gallery building was originally constructed in 1907 with 26 filters, with a 14-filter addition in 1937 and 7 filters added in 1964. After over 110 years of service, the structures started showing significant signs of deterioration, most commonly concrete spalling and reinforcing steel corrosion. This case study will highlight the methods used to evaluate the structures that involved conventional methods such as sounding, crack mapping, chemical and petrographic examinations, along with technology such as Half-Cell Potential/ICOR, Impact-Echo, Ground Penetrating Radar, and UAS (Drone) services.
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.
Nondestructive testing is often used in conjunction with traditional methods to assess construction, material, or structural deficiencies in new construction. This presentation describes evaluation of unique delamination failures within below-grade, exterior walls of a new subway station. The walls were conventionally reinforced mass concrete cast against a soldier pile and lagging retention system. Shortly after construction, leakage at cracks and joints was observed and injection processes led to delamination of the interior surfaces. The assessment objectives were to determine the extent and cause of near-surface discontinuities and evaluate the structural integrity of the walls. Nondestructive testing included flaw detection using Impulse Response [structural mobility testing] and reinforcement locating using ground-penetrating radar. Sampling and petrographic examinations were conducted to correlate test results with distress conditions and evaluate the in-situ concrete.