Earthquakes and Proper Waterproofing Earthquakes are unfortunately one of the unchanging items on our country's agenda. Before we had fully healed the wounds of the 1999 earthquake, we recently faced very large earthquakes affecting 10 provinces, searched for culprits, protested, and invited field experts to television programs. As a result, we clearly saw that our country is still not prepared for earthquakes. So how does one prepare for earthquakes? While it may not be possible to prevent earthquakes, is it possible to prevent loss of life or minimize the number of collapsed buildings? 95% of our country's population lives in seismic zones. However, we have seen that we are not where we would like to be in constructing safe, healthy and quality buildings. So what is the missing point? Earthquakes are of course primarily related to soil; soil surveys and fault lines clearly show us where settlements should or should not be built. Following this, one needs to bring together architect and engineer knowledge, the right products and proper workmanship. Static calculations need to be made according to earthquake risks, but this alone is not sufficient. Structural safety must be fully protected throughout the building's economic life.

Earthquakes and Corrosion

More than 85% of structures in our country are reinforced concrete buildings. According to research conducted in recent years, one-third of our housing stock of 20 million units has risky status from an earthquake perspective. In buildings, reinforced concrete sections carry compression loads. The earthquakes that occur exert lateral loads on the building and create moment effects. Concrete has no resistance to this (tensile strength). If iron reinforcement is not placed in the concrete or is placed in insufficient quantities, the concrete will break apart under the effect of this load. If the iron reinforcement inside the concrete corrodes, similar results occur. Although not widely known, corrosion is one of the biggest causes of destruction caused by earthquakes. After the 17 August 1999 earthquake, inspection of 55,561 residences and workplaces found that 64% of damaged buildings contained corrosion damage. Corrosion occurs in the chemical formation process of concrete through water entering from settlements and capillary cracks, combined with iron and oxygen gas present in the environment. Corrosion-related cross-sectional loss of concrete reinforcement means that after a 10-year period, the reinforcement loses 66% of its initial load-bearing capacity. Preventing corrosion caused by water seeping into the building from any source is only possible through waterproofing. The urban transformation process launched nationwide in Turkey could have been a great opportunity for waterproofing applications, but many situations such as lack of inspection and applications not conforming to standards prevented this opportunity from being realized.

Proper Waterproofing

According to Article 51 of the Standard Building Code that came into effect on 3 July 2017: "Heat and waterproofing insulation against external effects must be applied in all basement levels in contact with soil." No matter how strong buildings are, major destruction can become inevitable when waterproofing is not applied. Water seeping into the building in any way enters the concrete and causes rusting, i.e., corrosion. Waterproofing does not introduce significant additional costs when viewed against the total cost of the structure, representing only 2-3% of the total building cost. Spray-applied waterproofing is one of the latest developing water isolation methods. Water isolation materials obtained from membrane-like products with semi-fluid composition are applied using the spray method and set on the surface to create a waterproof structure. This method is the name of an application method rather than a product type. Similarly, next-generation proof membranes that adhere at every point to poured concrete and create an impermeable bond can be safely used in raft foundation and wall waterproofing applications. In addition to conventional products in waterproofing, along with developing technology, it will enable you to perform correct waterproofing with savings in labor and time, while also providing total cost advantages. Flexible spray waterproofing materials are used in approximately 30% of structures on basement level walls and foundations where concrete void filling and protection are not needed. Application of spray waterproofing on basement walls allows easy repair of the damaged area in case of damage during the usage phase. However, the same situation does not apply to foundations. Repair of sections located beneath the building becomes impossible during the usage phase. For this reason, using waterproofing membranes that flex and do not break under building loads for waterproofing purposes under foundations provides more favorable results. Liquid spray-applied waterproofing materials do not provide sufficient resistance under water pressure effects, which is why special products reinforced with carriers must be used. Since spray-based bituminous liquid membranes are flexible, they move with soil and structural movements without cracking or breaking. Additionally, resistance to chemicals in the soil, ease in waterproofing around irregular foundation sockets, and the absence of additional areas that could cause water leakage are among the other selection criteria. We know that bituminous membrane coatings are the most appropriate and reliable material to increase building resistance in the face of earthquakes. However, when we want to waterproof our residence or business premises, we encounter many options. At this point, many criteria come into play from the location of the project to the roof slope, and this can make correct material selection difficult. As ODE Yalıtım, we started from this point and developed ODE Select, an innovative service. ODE Select, an online system selection tool that is the first in Turkey and among the few examples in the world, brings together the most appropriate solutions and technical documents for construction projects within minutes. With the application, waterproofing solutions for roofs, foundations and walls, systems suitable for project criteria, 3D details, specifications and technical documents can be downloaded to the computer as a single file, completely free of charge. The system also allows obtaining price quotes or technical support from experts if needed. In this way, while establishing a strong information network between project developers and manufacturer expertise, we aim to prevent information pollution in the sector. For earthquake preparedness and quality buildings, what needs to be done together with urban transformation can be prioritized as follows: • Building codes should be fundamentally reviewed, consulting support should be obtained from expert firms and scientists, new buildings should be constructed and all old buildings should be inspected. If necessary, the use of seismic isolators should be made absolutely mandatory. • Soil survey, foundation, static project and on-site inspection in building construction must be conducted correctly. • Universities, especially engineering faculty students, should be continuously equipped with current information by leading sector companies and initiatives and incentives should be created for work in this field. • Cooperation between the private sector and public institutions should be strengthened and accelerated in every way. • Building inspection companies should be given an autonomous structure, and the relationship between service provider and recipient should be brought to a neutral position as soon as possible. • In the public sector, before creating technical infrastructure for all projects, factors that would prevent resource waste should be avoided. • Alternative to vertical architecture, horizontal architecture for earthquake zones, alternative structures such as steel buildings should be considered. • NGOs should organize informative training on earthquakes, especially waterproofing, in cooperation with universities and public institutions and organizations. Public awareness campaigns should be created to increase public consciousness. Timur Ergün Product Manager (Building Insulation) ODE Yalıtım