25 Year Milestone Inspection
Considering recent events, namely the Surfside Collapse of 2021, buildings along the coastline of Miami have been receiving more strict building codes to prevent similar disasters from happening. While any new structural requirements assist in having a more robust, new structure, any buildings constructed with the old structural requirements are more vulnerable to collapse by comparison. To amend this, the state of Florida modified the existing building recertification program to add a 25-year milestone inspection for buildings meeting the following requirements specified by the state as, “…buildings that are three stories or taller located within three miles of the coastline built on or after 1998”. After completing this 25-year Milestone Inspection, the building is also required to preform regular inspections every 10 years thereafter. Consequently, buildings abiding by the new building codes and older structures will be thoroughly examined to ensure public safety and prevention of structural failure.
25 Year Milestone Inspection Guidelines
Upon receiving an inspection notice, the initial examination performed by the inspector will be the Visual Examination. During this phase, if any cracks, distortions, or deflections are observed, further testing of the area will be required. Based on prior examination, the next phases of the inspection are the Testing and Manual Procedures. Specifically, the Testing Procedure will be performed if loading conditions are observed to be at a critical state. The Manual Procedure is specified by the state of Florida as, “chipping small areas of concrete and surface finishes for closer examinations are encouraged in preference to sampling and/or testing where visual examination alone is deemed insufficient”. Therefore, these areas should be in a least disruptive environment and easily repaired.
Continuing the 25 Year Milestone Inspection, details regarding Foundations, Roofs, Masonry Bearing Walls, Floor and Roof Systems, Steel and Concrete Framing Systems, Windows and Doors, Structural Glazing, Wood Framing, Building Façade, Loading, Electric Services, Branch Circuits, Conduit Raceways, Emergency Lighting, and Infrared Thermography must be provided if deemed necessary.
Regarding structural foundations, the principal point of analysis is movement of the structure. Therefore, a solid foundation is one with insignificant variations in grain size, density and moisture content. Moreover, the structure must have ideal loading where dead load is uniform. Small structural movements are significant if leakage through cracks results in deterioration. Any large movements are to be evaluated for fracture.
Depending on the type of roofing system, a varying analysis will be performed. Flat Roofs will be analyzed for deflections and their life limits. Wrinkling, cracking, and loss of gravel with the addition of punctures are examples of critical issues. Similarly, regarding Sloping Roofs, deflections will be analyzed and critical issues with these roof systems are deteriorations of rafters and joists and valley flashing.
Masonry Bearing Walls
Primary concerns are cracking, bulging, sagging, misalignment, and deterioration. In terms of importance, horizontal and vertical cracking is critical because of the role of columns and floor slabs. Although deterioration is an important issue, most columns are not sensitive to the point where deterioration is intolerable. These issues arise mostly from moisture penetration corroding rebar.
Floor and Roof Systems
Depending on the nature of the cast of the concrete slabs and beams, methods of repair may differ. Generally, if the damage is minimal, patching of the area will suffice. However, for more critical deterioration, like corrosion, require a more extensive repair process. Members such as Pre-cast, Steel bar joists, Cold formed steel joists, paper backed mesh and rib-lath are sensitive to corrosion. Whereas wood joists are sensitive to dry rot or termites. Finally, Gypsum roof decks must be analyzed if exposed to moisture.
Steel and Concrete Framing
Regarding Steel Framing, corrosion will be the primary issue analyzed. Some areas of importance are welds, bearings, and fasteners. To determine the condition of the steel, the state suggests Concrete fireproofing. Concrete deterioration is most likely related to rebar corrosion. The presence of small cracks are indicators of this, requiring patching whereas more serious cracks are more critical.
Windows and Doors
Windows and doors will be analyzed in terms of leakage and deterioration of anchorage. Due to the climate, the event of severe thunderstorms and high-speed winds will also be considered. While high-rise structures are further tested for inward or outward suction.
Applying to threshold buildings, the state specifies that, “structural condition and adhesive capacity of the silicone sealant” will be tested. After this inspection, subsequent inspections must be conducted every 5 years thereafter.
Principal issues with wood framing are the presence of dry rot, and corrosion of fasteners. To help indicate the wood’s condition, a pointed tool applied at moderate hand pressure will be administered.
The accessories, protrusions, or equipment mechanically or adhesively attached to the building will be tested with public safety and weather conditions in mind.
Due to the structure existing for at least 25 years, the need to test the original loading capacity is unnecessary. Moreover, the existence of new loading conditions must be properly justified as to not jeopardize the structural system.
A description of the electrical services distributed along the structure must be supplied. The state requires that this report contain, “size of amperage, if three (3) phase or single (1) phase, and if the system is protected by fuses or breakers”.
Regarding Branch Circuits, their conductors must be tested for performance. Further, proper grounding like an emergency generator must be present.
The general wiring of the structure will be analyzed. Conduits must be in good condition and not eroded. In this report, types of wiring must be described in detail.
Fire alarm systems, exit signs, and emergency lights must be in working condition.
Regarding electrical systems of at least 400 Amperes, a report of electrical equipment must be provided. The state requires, “busways, switchgear, panelboards (except in dwelling unit load centers), disconnects, VFDS, starters, control panels, timers, meter centers, gutters junction boxes, automatic/manual transfer switches, exhaust fans and transformers” to be included in this report. Moreover, a Level II or higher Thermographer must perform this inspection and must also have at least 7 years of experience in inspecting electrical systems in commercial buildings.
Typical Damages and Principal Points
When conducting structural inspections, the most significant damages that must be prioritized as stated by Eastern Engineering Group are, “Any structural element that shows cracks, spalling or deformation must be repaired.” Specifically, concrete slabs and columns exposed to moisture are vulnerable to cracks from corrosion of rebar and infiltration of moisture. Therefore, patching the cracks is strongly suggested to reduce the humidity entering the system. More severe issues like over-loading leading to large cracking require demand more urgent treatment, as the structural capacity is severely weakened. These matters and more are often observed when structural inspections take place. When in need of an inspection, please keep in mind that Eastern Engineering Group is more than qualified to inspect any low, mid, or high-rise structure.
To address these issues, Eastern Engineering Group is able to provide you with temporary repair plans, structural repair plans, and structural restoration plans. Temporary Repairs serve to restore pre-existing conditions and prevent further damage while a more long-term solution is devised. Structural Repairs are more long-term solutions to any structural failures addressed. While Structural Restoration is used to rehabilitate the original structural integrity. Therefore, as any problems arise, it is strongly recommended to apply corresponding treatment before the issue becomes more costly.
Effect of Weather on Coast-side Structures
With the primary concern of this inspection being to prevent the collapse of structures, it is critical to consider the effects of weather on the primary structural components. From the inspection guidelines, deterioration of steel components and concrete with higher moisture permeability due to exposure to moisture and a solid foundation is a large focus for prevention of structural failure. This is due to the high moisture and flooding caused by Florida weather. Further, due to analyzed structures being within 3 miles of the coastline, these conditions are amplified; hence the need for frequent structural inspections. Contact Eastern Engineering Group for your 25 Year Milestone Inspection needs. We will make sure the building in question complies with all of Miami-Dade County’s structural safety requirements.
©️ 2022 Eastern Engineering Group wrote and published this article. All rights reserved.
This information was strictly referenced from Miami Dade Country Structural Recertification.