The Avalon Mall parking facility is a four level above grade structure, consisting of three suspended parking levels (approximately 7,750sq.m. each) and one on-grade parking level connected to the existing mall with a new pedestrian bridge. RJC was the structural engineer of record. During construction of the parking structure extensive cracking of the suspended parking garage slabs was noted at two of the 24 pours. RJC undertook a visual assessment of the parking slabs in question to determine the extent of the noted cracking and determined over 750lin.m. of cracks ranging in size from 0.5mm to 6.5mm in width. Following the visual assessment destructive testing of the concrete was undertaken to determine its in-situ properties as well as to understand the full extent of the cracking.
A follow-on presentation to the discussion of our evaluation of over 1500 tire and lube facilities across the United States that prescribed immediate repairs where necessary, reinforcement where deterioration reduced capacity below acceptable levels and coatings necessary to protect structural steel and structural concrete (i.e. our 2019 Philadelphia presentation). This will be an in-depth presentation of how repairs were specified for (3) specific types of structures. The (3) structure types are exposed structural concrete, composite metal deck and fully reinforced form deck slabs all supported by steel structures and reinforced concrete walls. Presentation will include before, during and completion photos of each project discussed. Again, touch on the evaluation processes to include demand to capacity ratios review, evaluation system and inspection form, triggers to determine when shoring is necessary, calculation of capacities per AISC 360, ACI 318, ACI 562 and local building codes.
Two projects will be explored in this presentation. The first is a concrete structure which for 20 years was exposed to extreme heat. The second is a structure which was exposed to extreme vibrations. Both these structures were integral parts of manufacturing processes and required limited down time to repair. The questions needing to be answered were: what is the condition of the existing concrete and what are the repair options for these structures. We turned to non-destructive techniques to evaluate these structures. Non-destructive techniques can provide insight into structures when accompanied by experienced engineers and petrographic analysis. Repair options were provided at the end of our evaluation leading to reduced down time and well-planned repairs.
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 video will illustrate an example of how various sections of ACI 562 are applied in the execution of a complex repair project, the repurposing of a historic train deck into a transportation hub for light rail trains and busses. Methods of evaluation and analysis, as guided by ACI 562, will be presented with a discussion of how these provisions lead to various repair approaches presented to the owner.
This video will discuss how the requirements of ACI 562-16 are used in the evaluation and repair of parking structures. It will take participants through a representative garage project, utilizing Design Example 1 from the Guide to the Use of ACI 562 as the basis. Evaluation and design considerations will be discussed relative to the Repair Code as well as QA/QC and the Engineers' Role during construction.
This video will illustrate an example of how various sections of ACI 562 are applied in the execution of a Precast/Prestressed Double-Tee repair project. Methods of evaluation and analysis, as guided by ACI 562, will be presented with a discussion of how these provisions can lead to various repair approaches.
Codes and standards are developed for use by design professionals; however, the use of codes and standards significantly impacts Owners and Contractors. The ACI 562 code was motivated by the poor performance of repaired concrete structures, specifically premature failure of repairs and limited durability of repaired structures. Development of the code was intended to benefit owners and contractors by improving performance and perceptions regarding repairs to existing structures.
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.
The case-histories based presentation will focus on the use of nondestructive evaluation (NDE) methods to detect flaws and damage in concrete construction. Case histories will be presented for detection and mapping of flaws and damage in concrete such as cracking, delamination, honeycomb, void, corrosion, fire damage, alkali-silica reaction and low strength concrete. The case histories for the concrete structures are anticipated to include parking structures, bridges, buildings and dams. NDE methods will include sonic/ultrasonic, infrared thermography, radar and corrosion technologies where the results in many cases were confirmed by coring. The use of some of the NDE methods for QA of concrete repairs such as epoxy injection and patching will also be discussed.