SCA CONSTRUCTION CONCEPTS

INTRODUCTION

The occurrence of strong earthquakes when and where they happen is a natural phenomenon that is extremely difficult to predict and can cause enormous losses worldwide. In the past year alone, according to the United States Geological Survey (USGS), earthquakes and their secondary effects, such as tsunamis, have resulted in approximately 300,000 casualties and material losses totaling 1,000 trillion. Since earthquake prediction and engineering solutions have not yet reached a definitive stage, the study of the engineering aspects of earthquake-resistant structures remains a highly relevant area of research.

Over the past 10 years, the concept of earthquake-resistant design has shifted from a focus on structural strength and individual structural elements to a design approach based on limit states, known as Performance-Based Design. This change in design philosophy was first introduced in the 1995 review by the Structural Engineering Association of California (SEAOC) and the Applied Technology Council (ATC). The new concept was subsequently documented in NEHRP 1997, FEMA 302, and UBC 1997, and most recently incorporated in SEAOC Vision 2000.

This shift in trend is due to several factors, namely:
1. In response to the structural failures of conventional design methods particularly strength-based design—observed during several major earthquakes, including the 1989 Loma Prieta, 1994 Northridge, and 1995 Kobe earthquakes (as documented in reconnaissance reports), traditional methods were deemed inadequate in accommodating earthquake loads and their effects.
2. It is necessary to control structural performance, primarily to ensure the stability and seismic resilience of the structure during strong earthquakes.

This book presents the concept of formulating earthquake-resistant construction using the direct deformation method as a means of controlling structural performance. The direct deformation method is defined as an analytical procedure based on estimating the lateral displacements expected to occur due to earthquake-induced ground shaking. Design force components are then determined based on these calculated deformations. Consequently, lateral deformation or displacement becomes the primary design parameter, directly linked to the overall structural response.

THE BOOK PRESENTS the concept of formulating earthquake-resistant construction using the direct deformation method as a means of controlling structural performance. The direct deformation method is defined as an analytical procedure based on estimating the lateral displacements expected to occur due to earthquake-induced ground shaking. Design force components are then determined based on these calculated deformations. Consequently, lateral deformation or displacement becomes the primary design parameter, directly linked to the overall structural response.1. As a maximum effort to respond to failures that frequently occur due to earthquakes., 2. As a maximum effort to develop an earthquake-resistant structural analysis model to prevent severe building failures that could endanger human life.

EARTHQUAKE ENGINEERING FOR CONSTRUCTION

Assoc. Professor Dr. Ir. Ayuddin., S.T., M.T., IPU., ASEAN Eng., ACPE., APEC Eng.
(Researcher and Analyst of Earthquake-Resistant Structures )

The concentration in structural civil engineering is a highly engaging and critical field that encourages serious academic study because it is directly related to the safety and well-being of human life. One of the main objectives in this discipline is the design and analysis of building structures capable of resisting earthquake loads. Buildings that are designed or analyzed in accordance with earthquake-resistant principles play a crucial role in protecting human lives, as earthquakes can generate extreme forces that may lead to partial or total structural collapse. Earthquakes are unpredictable natural phenomena that can occur without warning, and their effects are influenced by factors such as ground motion intensity, soil conditions, building location, and structural design. In active earthquake zones, peak ground acceleration (PGA) can reach 0.4g or higher, placing significant demands on the structural integrity of buildings.

Given these challenges, buildings must be designed with careful and precise analysis to ensure that they can withstand severe earthquake forces while minimizing structural damage and preventing loss of life. This requires not only a solid understanding of the mechanical behavior of materials but also knowledge of advanced structural analysis methods, including dynamic analysis, response spectrum analysis, and performance-based seismic design. Engineers must consider the interaction between structural and non-structural elements, as well as the integration of building service systems, which can also be affected by seismic activity. Furthermore, different types of structural materials such as reinforced concrete, steel, and timber exhibit different behaviors under seismic loading, necessitating specialized expertise for each system.

In addition to technical knowledge, experience and judgment are essential in evaluating how various design alternatives respond to earthquake effects. Seismic-resistant design principles include controlling lateral displacements, ensuring adequate ductility, proper detailing of connections, and providing redundancy in load paths. Modern structural engineering increasingly relies on computational tools and software to model complex structural systems and simulate their response under realistic earthquake scenarios. This combination of theoretical knowledge, practical experience, and technological tools enables engineers to optimize structural performance, enhance resilience, and achieve both safety and cost-effectiveness in earthquake-resistant construction. Ultimately, the field of structural civil engineering is not only about creating buildings but also about safeguarding human life and contributing to the sustainable development of urban environments in seismic-prone regions.

One method of linking earthquake forecasts to the design and analysis of a building is through numerical modeling. Earthquake engineering is greatly enhanced by modeling how different types of structures respond to seismic activity. Experience with the latest versions of finite element analysis programs, such as Etabs and SAP2000, is essential for designing and modeling structures. Structural damage can be significantly reduced through accurate prediction of potential future earthquakes during the structure’s lifespan and through precise modeling of the structure’s nonlinear behavior under seismic loading.

Earthquake engineering has evolved from relying on prescriptive provisions aimed indirectly at ensuring life safety to a performance-based approach. This shift represents a major advancement in the field, as it moves beyond minimal compliance toward a more thoughtful, scientific, and proactive method of protecting lives, property, and infrastructure. The performance-based approach offers several advantages, providing a more effective means of designing structural systems to achieve specific performance objectives. It consistently considers seismic hazards, structural response, and potential damage, allowing for a comprehensive probabilistic assessment of the expected performance of the structure.

In my opinion, embracing performance-based earthquake engineering is not just a technical necessity but also a moral imperative. Traditional design codes provide a baseline level of safety, but they often fail to capture the complexity of real-world seismic events. By integrating advanced modeling techniques with performance-based criteria, engineers can anticipate vulnerabilities that may not be obvious through conventional methods. This approach not only enhances the resilience of individual buildings but also contributes to the broader safety and sustainability of urban environments. Moreover, investing in such predictive and analytical methods may initially require more resources, but the long-term benefits reduced repair costs, minimized casualties, and increased public confidence far outweigh the initial investment.

Ultimately, performance-based earthquake engineering exemplifies how modern science and engineering can align with human-centered priorities. It challenges engineers to think beyond prescriptive rules and encourages them to innovate solutions that can withstand uncertainty and protect communities. For anyone involved in structural design, understanding and applying these principles is not merely a professional skill but a responsibility to society.