{"id":1595,"date":"2024-11-13T10:35:48","date_gmt":"2024-11-13T10:35:48","guid":{"rendered":"https:\/\/openseeshouse.com\/en\/?page_id=1595"},"modified":"2024-12-09T15:17:34","modified_gmt":"2024-12-09T15:17:34","slug":"prescriptive-code-based-design","status":"publish","type":"page","link":"https:\/\/openseeshouse.com\/en\/prescriptive-code-based-design\/","title":{"rendered":"Prescriptive or Code-Based Structural Design"},"content":{"rendered":"

In this section of OpenSeesWiki<\/strong>, we aim to provide an overview of the prescriptive design process used by traditional structural design codes. After familiarizing ourselves with the fundamentals of these codes, we will review the issuance process to gain a precise perspective on structural design procedure. Alongside knowledgeable design capability, this familiarity will give us the ability to achieve two key goals when working with OpenSees on research projects:<\/p>

  1. Many structural research projects centered around nonlinear analysis in OpenSees<\/strong> aim to evaluate and improve design codes. A deeper understanding of these codes and their development process enables us to participate more effectively in such studies.<\/li>\n\n
  2. Understanding prescriptive codes is a foundational step toward a deep comprehension of performance-based design processes with OpenSees. In the future, we\u2019ll explore why no performance-based design method is entirely complete, as they inevitably prescribe certain design choices. In practice, prescriptive methods evolve step-by-step to approximate fully performance-based approaches. Therefore, grasping these prescriptive methods serves as the starting point for proposing a performance-based design process.<\/li><\/ol>

    The content in this section, along with the objectives outlined, will help provide clear answers to questions like Why OpenSees?<\/em> and Why nonlinear structural analysis?<\/em> In other words, once we understand the research processes behind developing prescriptive codes and the role of nonlinear analysis in performance-based design, it becomes evident why OpenSees is the best available tool for our needs.<\/p>

    Before outlining the process of issuing prescriptive codes, let\u2019s briefly review the prescriptive building design process based on the ASCE 7 standard.<\/p>

    example of code-based or prescriptive structural design<\/h2>
    \"\"
    The seismic design process of structures based on the ASCE 7 code<\/figcaption><\/figure><\/div>

    After setting all the prerequisites, it is your turn to model the structure in OpenSees or another analysis software. In other materials from the OpenSees House, we have explained the advantages and challenges of using OpenSees in this process. By creating the model, applying loads, and analyzing it, you can obtain the force and displacement responses of your model in its members and floors. These responses essentially represent an estimate of the earthquake demands on your structure. In other words, an earthquake imposes demands on your structure, and your structure must be designed to meet these demands.<\/p>

    After estimating the demand, the next step is to check the capacity of the members against the imposed demands on the members and floors. If this balance does not indicate a superior structural capacity in an economical way, you must make adjustments to the sections and other specifications of the structure. This is a trial-and-error process, and due to its relative complexity, the final result largely depends on your experience. The reason for this complexity is that the imposed demand on the structure is not only a function of the loading and environmental conditions but also significantly influenced by the characteristics of the structure itself. As a result, your understanding of the structure’s behavior and the relationship between the imposed demand and the structural characteristics is a highly influential factor.<\/p>

    The process of developing prescriptive codes.<\/h2>

    After this introduction, an important question arises: Where do prescriptive design guidelines come from, and through what process are they developed? To understand the process of creating prescriptive codes, let’s use an example. Imagine the Department of Education in a city decides to issue a guideline for improving the physical health of its students. If we put ourselves in the shoes of the officials in charge, we can imagine the following process for developing a dietary guideline:<\/p>

    1. Classifying students based on gender, age group, residential area, and other factors<\/li>\n\n
    2. Selecting a number of students as a sample from each category<\/li>\n\n
    3. Studying the physical condition and eating habits of the selected samples<\/li>\n\n
    4. Prescribing an appropriate strengthening diet for each group and communicating it to the schools<\/li><\/ol>

      This process is a completely standard and logical one because:<\/p>

      • It is based on sufficiently accurate information about the details of the issue<\/li>\n\n
      • It clearly sees the various different scenarios that play a role in determining the details of the issue<\/li>\n\n
      • With an appropriate statistical approach, it is able to significantly reduce the likelihood of food insecurity after the implementation of the plan over a period of time<\/li><\/ul>

        The centers that issue building design guidelines follow exactly these steps:<\/p>

        1. They categorize buildings based on primary materials, structural system, height, degree of irregularity, and type of use<\/li>\n\n
        2. A sufficient number of samples are selected from each category and studied using laboratory and analytical methods<\/li>\n\n
        3. With the goal of controlling the probability of structural failure in meeting the performance requirements based on their intended use, their needs are estimated<\/li>\n\n
        4. They prescribe guidelines that, when followed in the design process, ensure the fulfillment of the identified minimum requirements<\/li><\/ol>

          Disadvantages of Prescriptive Design<\/h2>

          In the article titled “Performance-Based Design of Structures,” we will explain that prescriptive guidelines cannot account for the specific conditions and needs of our structure. As mentioned above, these guidelines are always aimed at a broad category of structures similar to ours, and as such, they do not fully align with the specific characteristics of our structure.<\/p>

          Furthermore, these guidelines aim to achieve performance objectives that have been identified as the “minimum acceptable” by the committees responsible for drafting the codes. As a result, even if they precisely account for the behavior of our structure, they cannot design the structure based on the specific performance expected by us.<\/p>","protected":false},"excerpt":{"rendered":"

          In this section of OpenSeesWiki, we aim to provide an overview … <\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1595","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/pages\/1595","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/comments?post=1595"}],"version-history":[{"count":5,"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/pages\/1595\/revisions"}],"predecessor-version":[{"id":1741,"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/pages\/1595\/revisions\/1741"}],"wp:attachment":[{"href":"https:\/\/openseeshouse.com\/en\/wp-json\/wp\/v2\/media?parent=1595"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}