C. S. Doo's scientific contributions

Inspired by the seminal paper by Michell (1904), engineers have investigated several tools for the optimization of structural shapes and systems to be employed during the design process. Structural optimization attracts increasing interest in the building industry, especially in the design of high-rise buildings. By selectively distributing the structural members in the building, the efficiency of the resulting design can be optimized; often aesthetically pleasant form can be achieved. Although Michell trusses represent a valuable starting point in defining optimal structural systems, analytical solutions have been derived only for relatively simple load conditions and geometries. Recently, along with the increased computing power, efficient numerical methods have been developed to generate optimal structural solutions for various problems. This paper presents recent developments in optimization methods which have been used for the design of novel structures. Concepts of growth, genetics, and emergence are introduced as context into the fundamental concepts presented. Growth patterns in nature can service as guidelines of how an optimal structure might be conceived. Genetics provide an understanding of how the blueprint of life, DNA, can be used to develop optimal solutions using genetic algorithms. Emergence theory suggests that interactions among parts serve to create something that is not realized until individual parts work in concurrence to comprise the whole. This concept is displayed through topology optimization. Several high-rise structures are described as examples of how these concepts can be applied to the development of structural systems.

This paper presents the process for establishing and validating the design properties of Triple PendulumTM seismic isolation bearings which were utilized to achieve the superior seismic performance of the New San Bernardino Court facility. The analysis parameters of the nonlinear elements used in the analysis model representing the seismic isolation bearing properties were confirmed through a prototype bearing test program and specification completed during the construction document design phase. The prototype test program and specification was developed considering ASCE 7-05 Chapter 17 requirements and preliminary structural analysis results including horizontal and vertical force-displacement characteristics, as well as axial load demands on the bearings. The final prototype test results verified the characteristic properties of the bearings at various vertical loads and displacements at real-time earthquake motions and the results validated the assumed properties used in the structural analysis and design. The real-time dynamic test program extends current ASCE 7 prescriptive requirements.

Structural forms and processes that arise organically in nature can be scientifically analyzed in an effort to produce strong, efficient, and elegant structural systems for the built environment. Incorporating these natural solutions into structural designs is challenging, often requiring that these forms and processes be carefully studied, quantified, and reproduced under real-world conditions. The results—structural systems that are adaptable, constructable, and cost effective—are well worth the effort.

This paper presents an overview of the "Enhanced" seismic design of the New San Bernardino Court facility. Designed for the Judicial Council of California under the jurisdiction of the Administrative Office of the Courts, the state-of-the-art Superior Court facility will be located in the City of San Bernardino, California — a region of high seismicity in close proximity to active earthquake faults. The 12-story structure with one below grade level was designed to meet "Enhanced" seismic performance objectives of the 2006 California Trial Court Facility Standards in accordance with the 2007 California Building Code. The final design features a cost-effective steel-framed superstructure with special moment-resisting frames and supplementary viscous damping devices supported on a triple-concave friction pendulum seismic isolation system. This paper focuses on the overall progression of the final design from early design phases through final construction documents. This includes architectural design development, site-specific seismic hazard evaluation, structural system options considered, as well as, seismic risk assessment and life-cycle cost analysis to help inform decision making and system selection.

Organic and natural solutions have great value as they have, over time, been shaped by nature. Incorporating these organic and natural solutions in building design offers the challenge to quantify these solutions and to derive systems that are adaptable, constructible and cost effective. Adaptations and mathematical derivations that use nature's mechanics in structural design have led to innovations in structural systems. These organically-inspired structural systems typically exhibit interesting aesthetic qualities which are not necessarily intuitive. Two design examples are explored which incorporate nature's mechanics. First, geometric properties of bamboo, as they relate to structural shape, material placement and efficiency, are examined and applied to the China World Trade Center (CWTC) Tower Competition. Second, the logarithmic spiral—found in forms ranging from all the way from shells, seeds, and plants to spider webs, hurricanes, and galaxies—was interpreted and applied to the ultra-tall Transbay Transit Tower Competition, scientifically mimicking natural force flows of a cantilevered structure to its foundation.