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  • Strengthening Existing Buildings

    In many parts of the country, including the mid-South, When renovating an older building, it is rare to strengthen it to the performance standards of new construction. The required strengthening tends to be a gray area, where an engineer has some latitude. We approach this case-by-case based on factors such as the customer’s needs, the age and condition of the building, historical precedent for similar projects, and any directives by the jurisdiction. Most older buildings have severe seismic liabilities that were not accounted for when the building was built. Add to this the reality that the brick, mortar, and wood framing have all deteriorated and may continue to degrade due primarily to moisture infiltration and trapping. Also, consider that the proposed renovation will further weaken the building by increasing or adding wall and floor openings as well as material weights. Or even just by removing the lath and plaster sheathed studwall partitions and opening up a floor plan, we are also weakening the structure. These changes may trigger strengthening requirements in the IEBC. Yet in our region, the design engineer and the governing jurisdiction often ignore these triggers. Is this what the owners and architects want? They are investing in a building, expecting that their investment is sound and that the building is safe. At Ozer, we have a high standard of care. We will only work on a building if we can include repairs or strengthening so that when the project is complete, the structure overall is a little stronger and more resilient than it was when we found it. Our rule is that when we are done, we leave a building stronger and safer than when we found it, even if we can't make it as strong as a new building. For example, removing a bearing wall to open up space may weaken the building because that brick-bearing wall serves as a shear wall. So we will add connecting elements to deliver the lateral forces to other parts of the remaining shear wall. Or we may need to strengthen other walls or as a last resort, install new shear walls. That's why we often give the owner a couple of options. The minimum option is it's a little stronger and more resilient than how we found it. The better option is we've fully implemented the IEBC requirements. In either case, the completed renovation can better handle an overload such as a big storm or small earthquake. And it also means we've arrested the decay; some older materials break down much quicker than modern materials. In particular, the old brick and lime mortar, if it's a brick structure. In other cases, deterioration of the wood or steel has begun, and we want to identify and address the source of the moisture intrusion or treat the wood, masonry or steel to protect it down the road. And this is sometimes a complex procedure. Sometimes we are on the defensive; the owner wants to do the bare minimum as they see it: remove the wall and provide gravity supports at the affected area. In such cases, we walk away from the project. For better or worse, other engineers will do the job just as he wishes.

  • Preserving Existing Buildings

    Each time we are asked to work to preserve historic buildings or landmarks, we start by looking at the project from two different perspectives. One perspective is seeing the aspects of the project that are similar to working on new construction. The second is being prepared to foresee characteristics uniquely inherent to aging buildings, which other engineers may not be as familiar with and which may not be addressed by current Codes. The first step is detective work. That is solving the riddle of how the building was built and understanding the archaic materials and systems used and the effects caused by time and moisture. One example, we must understand cast and wrought irons and how they differ from each other and modern steel. Another is being well-versed in the properties and capacities of mortars, masonry materials, and wood products used for construction. Then we determine the extent of the damage and deterioration, the causes, how to mitigate them, and how to integrate and connect the new elements needed to restore it. The mid-South has additional regional challenges, such as requirements for seismic anchorage. Historically, construction materials used in this region of the country were not as high quality as in more industrialized regions. Also, there is a shortage of skilled craftspeople to provide the restoration labor. Budgets for any restoration work are typically tight as well. The buildings we strive to preserve here simply start off having less monetary value than those built in preservation-rich areas such as Chicago or New England. In the mid-South, we will lose buildings to immediate demolition or, more slowly due to substandard work if our proposed solutions are not cost-effective or not fully implemented. Even with this challenge, it is possible to find solutions that stand the test of time, and when we do, it is beautiful. We strive to find clients interested in quality preservation. We must work closely with architects, contractors, specialty craftspeople, restoration and repair industry experts, government agencies, and preservation-focused entities to achieve long-term results.

  • Working with Old Brick and Mortar - The "Damp Proof Course"

    As discussed in our prior post, "Revitalizing History: Ozer Engineering's Innovative Timber Solutions for Somerville's Museum," we have been working on preserving a historic building in downtown Somerville, TN. Recently, our focus has been on restoring the old brick-and-mortar facade. When we initially uncovered this exterior wall, we found the bottom three feet of brick and mortar completely decomposing and crumbling. What went wrong? This is a common condition in older brick buildings with brick foundations. In this case, there was a brick basement. Moisture from the foundation will wick up the wall through capillaries in the brick-and-mortar. This is a condition called "rising damp." Traditionally, before the era of concrete foundations, this was addressed during construction with the insertion of a "damp proof course." Usually, this was a granite or slate course just above the foundation, which would break the wicking action. The extreme level of disintegration in this particular building had a second factor that exacerbated the situation. A previous owner applied corrugated sheet metal to the inside of the wall over the interior plaster to keep the interior dry. This created a barrier that prevented the drying of the wall to the interior of the building, causing the wall to become waterlogged and pressure to increase. That situation was extremely destructive to the old and insufficiently fired interior brick and lime mortar. So, at this stage, we have determined what went wrong. How do we preserve this historic building and have our repairs serve future generations? Our strategy includes four main components: Replace the damaged brick and mortar, including the header courses, with new modern brick and natural hydraulic lime mortar. Unload the wall. This wall is unsuitable as a bearing wall, especially in our seismic zone. We are installing an interior heavy timber frame to support the floor and roof. We also will anchor brick walls to each floor and roof with through-wall anchors. You have likely seen these cast iron stars on the exterior of other historic buildings in the area. Allow the wall to dry out naturally to the interior. An 8' stud wall will be installed in front of the brick. It will be open at the top and vented at the bottom. Also, a dehumidification system is planned for installation in the basement. Install a new damp-proof course. Europe has developed new technologies for injecting into masonry specifically for this purpose. The injection fluid fills and seals the capillaries to prevent wicking. The product we have specified for this project is Koster Crisin 76. Stay tuned for updates on the construction progress. Several aspects of our design are new or uncommon in the mid-south, including using Natural Hydraulic Lime mortar and the Damp Proof course technologies. Finding subcontractors experienced with using these is an important step in the process.

  • Revitalizing History: Ozer Engineering's Innovative Timber Solutions for Somerville's Museum

    At OZER Engineering, we are excited to collaborate with Architect Andy Kitsinger, Wagner Construction, and the Town of Somerville on the restoration of a historical landmark located at 16750 CR 64 in Somerville, Tennessee. This pre-civil war brick building with wood floors that anchors the town square was a well-detailed major structure for its time. Over the years it has had a rich history of many uses including a hotel, stores, and doctor's offices. The Town of Somerville recently purchased the building with plans to convert it into a museum. As they began to plan their vision for the space, they noticed cracks and settlements. So, they called OZER, smart move! Our assessment found the interior brick to be second class brick with no weather grade, commonly used on interiors in the pre-industrial south, known locally as "salmon brick" due to it's orange color. This brick breaks down when wetted for long periods. All around window and vent openings, and adjacent to sidewalks this brick is rapidly breaking down and can no longer support the weight of the building. Collapse of the building could be imminent, especially if subject to a lateral loading event, such as even a small earthquake. A common solution is to tear the building down. But what to do with a historic building that's important to the community? Join us on our journey as we bring new life to this treasured building. Preserving History with Innovative Timber Solutions: We needed to come up with a repair solution that could keep the renovation within the town's budget. A big part of our ability to create an affordable design is utilizing a timber frame. Usually, this type of work is done in steel. However, not only does steel give an inauthentic look and feel to historic restoration, but also the cost is significantly higher. With our expertise in developing cost-effective timber solutions, we designed a complete internal timber frame, a new skeleton, to carry the weight of the floors and roof, along with new CMU shearwalls that will resist wind and seismic load. Retaining the Beautiful Historic Façade: We recognize the importance of preserving intricate brick facades. Luckily the exterior wythe that people see is made of a different, first-class well-burnt brick that has held up well and been maintained over time. Through careful planning and anchoring, the internal timber frame will separate the load-bearing responsibilities from the façade, so it will remain in place, but only as a non-structural façade and envelope. By sealing the façade and repairing the interior brick, and protecting it from moisture, the decomposition of the interior brick can be slowed so that this exterior skin can survive for several more generations. Updates and Progress: Due to the extreme fragility of the badly deteriorated exterior brick walls, including basement brick retaining walls, we have to be very careful not to destabilize the structure during the installation of the new structural elements. Each step of construction has to be carefully planned to allow partial demolition and excavations without creating instability. And all this has to be done on a tight budget foregoing the normal approach of steel framing, instead using timber and conventional wood framing, carefully tying together the existing elements, and bracing them all back to the new CMU shearwalls. We carefully evaluate the existing wood and brick materials and produce a custom repair procedure. Then using primarily off-the-shelf, low-cost clips, screws, straps, and anchors to stitch the new and existing wood and masonry elements together. We present these design details on a clear set of drawings that wood framers and masonry repair technicians are able to understand and implement. Amazingly we are moving forward with this full structural renovation. It is very rare in this type of building and one in this condition. We are able to accomplish this because we have an experienced team at Ozer working together with Andy Kitsinger and Wagner Construction to find the most economical way to implement and guide the project through. In July, we will post updates on construction progress.

  • Ozer Engineering's Insights on Hot Dip Galvanization: Mitigating Overhead Corrosion Risks

    Through a recent inspection at a galvanization facility in Arkansas, we uncovered significant capacity loss in long-span steel girders located above the galvanization baths. This finding underscores the need for proactive measures to mitigate corrosion effects and ensure the structural integrity of buildings. Discovering Capacity Loss in Long Span Steel Girders: During our inspection, we encountered a concerning issue: long-span steel girders had experienced a considerable loss in load-carrying capacity due to the corrosive effects of the galvanization process below. This corrosion, resulting from the emissions released during galvanization, had gradually weakened the steel, posing a potential risk to the structural integrity of the affected buildings. Mitigation Strategies: Our Commitment to Long-Term Durability: At Ozer Engineering, we believe in proactive and innovative solutions to combat corrosion risks. Through enhanced protective coatings, regular inspections, and collaborative efforts, we can ensure the longevity and durability of structural steel: Enhanced Protective Coatings: Applying advanced high-performance paint systems or epoxy coatings can act as an additional layer of defense against corrosion. These coatings serve as a barrier, minimizing direct exposure to corrosive emissions. Regular Inspections by Qualified Engineers: Routine inspections conducted by experienced structural engineers allow for early detection of corrosion and degradation. This enables targeted maintenance or repair interventions to restore the load-carrying capacity of affected steel components. Collaboration for Best Practices: We emphasize the importance of close collaboration between structural engineers, galvanizers, and facility operators. By sharing insights and experiences, we can collectively develop strategies to mitigate the impact of galvanization emissions on structural steel.

  • Transforming Travel Experience: Memphis International Airport Concourse B Modernization

    Memphis International Airport recently completed a renovation of Concourse B. This major project, led by architectural firm UrbanARCH, brought together a team of talented professionals to create a state-of-the-art concourse that seamlessly blends functionality, aesthetics, and art. One of the standout features of this renovation is an awe-inspiring art installation titled "Intertwining" by renowned artist Yancy Villa-Calvo. Under the expert guidance of Architect Brg3s and Ozer Engineering, the integration of this mesmerizing artwork elevates the airport's ambiance. "Intertwining": A Fusion of Art and Engineering As part of the Concourse B modernization project, Yancy Villa-Calvo's captivating art installation, "Intertwining" was incorporated. The art installation, inspired by the vibrant culture and soulful history of Memphis, showcases a series of intertwining metal ribbons suspended from the ceiling, creating a stunning visual experience for passengers. These dynamic, flowing ribbons represent the harmonious convergence of diverse elements, mirroring the unity and connectivity found within the city itself. At Ozer Engineering, we played a crucial role in realizing the vision of "Intertwining." We were enlisted to design invisible supports for the art installation. By ingeniously concealing the support systems, the artwork appears to be floating, creating a sense of ethereal beauty and wonder. We analyzed the structural integrity of the concourse to determine the optimal design and support systems for the art installation. We were able to find a solution that not only met the highest safety standards but also allowed Villa-Calvo's artwork to take center stage.

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