Dr Mihailo D. Trifunac is a professor of earthquake engineering at the University of Southern California. He recently published a review paper on earthquake response spectra in Soil Dynamics and Earthquake Engineering. The opening paragraphs, in my opinion, represent an excellent essay on the relationship between engineering research and design code writing.
Design codes should be simple and robust, and their procedures directly based on sound understanding of the physical nature of the problem. Achieving this is difficult, especially when large, nonlinear, and chaotic dynamic response is involved. Those who work on code formulation must possess a wide range of expertise spanning all disciplines from strong earthquake ground motion to dynamics of structures, so that all relevant advances can be synthesized and the uncertainties minimized. Such requirements seem at first to demand a multi-author work. Yet that approach may be doomed from the onset, because the essence of the problem is to develop a unified and balanced synthesis. That consideration dictates single authorship, despite all the difficulties it poses. Inevitably, that single author would have to perform the most difficult task of assimilating material from many disciplines, and would require guidance and help from many colleagues. This view, which is at odds with the manner in which collective committee decisions have been made in the past developments of earthquake design codes, may explain in part why we have inherited so many incompatible and inconsistent formulations in the contemporary codes.
Ideally, the design codes should be formulated based directly on in-depth understanding of the intricacies of the nonlinear response of structures, in a way, which wisely simplifies the complex phenomena and grasps the significant and dominant phenomena. This view is also at odds with most of the current code development approaches, which rarely start anew from the evolving knowledge about the physical nature of the problem, and typically focus only on fine-tuning of the governing parameters and on the development of correction procedures aimed at extending or correcting the contemporary codes for the observed discrepancies.
from Trifunac, M. D. (2012). Earthquake response spectra for performance based design — a critical review. Soil Dynamics and Earthquake Engineering, 37:73-83.
Indeed, the current incremental code development approach makes codes thicker and thicker, design equations longer and longer (with more and more parameters), and understanding of the codes more and more difficult. In many ways, this also has made engineering education more and more difficult. Oft-times, professors are so busy to try to cover all the correction parameters that no time could be set aside to explain the first principle dominated in the design equations.