A Primary Study On Seismic Conceptual Design

Strong earthquakes brought countless tremendous damages to human.Especially, since20thcentury, great earthquakes caused huge losses of propertyand lives, which seriously endangered the social harmony and sustainabledevelopment. These severe earthquake disasters always challenged human’scognition and defense capability. A great deal of research showed that themajor reasons causing the losses of lives and economy were all closely relatedto the lack of seismic capacity of buildings, infrastructures and other civil workson earth, and might even say that the civil works with unqualified seismiccapacity were the prime culprit for earthquake disasters. The long strugglehistory with earthquakes disasters made us deeply realize that to really reducethe seismic damage and prevent human from seismic hazards, the only way wasto construct the civil engineering environment which are indispensable for ourliving and working more resistant to earthquakes. To this end, all theearthquake-threatened countries and regions all over the world establishedmany seismic design codes for different kinds of civil engineering to resistearthquakes.The seismic design codes usually includes the quantitative calculation orchecking computations with rational basis, and the ideas created by theaccumulative engineering practice experiences what is called the seismicconceptual design. For quite a long time, the computations with rational basishave been paid much attention in engineering and academics, while theconceptual design and its ideas have always been thought as qualitativeexperiences with certain ambiguity and uncertainty, which are mainly off the topof one’s head and difficult to innovate and develop. However, the authors findthat the seismic conceptual design plays an important role in the seismic designof structures, which is also a significant part of seismic design codes and thefundamental factor to determine the seismic capacity of structures.The seismic conceptual design has rich connotations. The authors thinkthat it can be grouped into two categories. One is the conceptual designtraditionally used in the engineering practice, which are the specific designconcepts mainly created by the lessons and experiences from the seismicdamage, including design technique and ideas related to the general layout of buildings and structures and the determination of detail construction. In thispaper, this kind of seismic conceptual design is called traditional conceptualdesign, or “strict conceptual design”. In addition to this, the authors find thatthe other kind of concept and conceptual design exist in the seismic designcodes, which is based on the rational thinking and analysis so as to realize thegeneral goal and requirement of seismic design, and it is different from thetraditional conceptual design concluded from the engineering experiences. Thiskind of conceptual design can be called as concept and conceptual designobtained from rational analysis or artificial design, i.e.,“designed concepts”,called “generalized conceptual design”, such as “no collapse under severeearthquake, repairable under moderate earthquake, and no damage underfrequent earthquake”,“classification of seismic protection”,“school and hospitalbuildings with higher seismic requirements than ordinary buildings” and so on.In this paper, the occurrence, development and final formation processes ofseismic conceptual design are systematically studied, and then its importantroles in the seismic design are discussed. Moreover, the connotation andgeneral rules of the seismic conceptual design are proposed. Finally, theclassification and its rational basis of the seismic conceptual design areexplored by the use of the philosophical views from the points of engineeringand engineering mechanics. The main researches and achievements areconcluded as follows:(1) The universality and importance of seismic conceptual design arediscussed. Limited to the human’s cognitive limitation of earthquake scienceand the severe non-linearity, great uncertainty and extremely complexcausation included in the seismic damage being gradually replaced by therelativity, to ensure the efficiency of the seismic design, it requires that thedesigners have more comprehensive and more systematical seismic conceptualdesign ideas. However, the focus researches on the seismic conceptual designof structures are not too much and develop slowly. The research in this papermay play an important role in pushing the development and application ofseismic conceptual design of structures.(2) By the analysis and discussion on the traditional/strict conceptual design,the more accurate definition is given based on the conceptual design ideas inthe current seismic design codes of China, USA and Europe, i.e., the basic designprinciples and ideas in accord with engineers’ professional basic theory and general knowledge created by the seismic damage and practical experiences,along with the process of general arrangement and determination of detailconstruction for the designed buildings and structures. Then the inherent lawsand the main characteristics of the seismic traditional/strict conceptual designare studied, i.e., empirical, objective, inclusive, renewable and regional.Furthermore, the scientific classification is done to make its whole structuremore clearly.(3) According to the seismic damage characteristics of different kinds ofstructures, the seismic strict conceptual design ideas based on the lessons fromthe earthquakes and engineering experiences as well as their rational basis areanalyzed and revealed. Moreover, by using dialectical materialism method andsimple mechanical analysis, the general rules of development and formation oftraditional/narrow seismic conceptual design are explored, i.e., combination ofinterior and exterior, rigid and soft, strong or weak, advantages anddisadvantages, and preparedness averting peril.(4) The ideas of “generalized seismic conceptual design” are proposed, and itsdefinition is given as the seismic design concept based on the general seismicdesign goal by serious and continuous rational thinking and deduction, andalso obtaining the peer recognition. It has the characteristics of subjective,abstract&vague, directive and symbolic and is classified from the view of theclassification of seismic protection and seismic fortification goal. Then by thecomparative analysis of the development and differences of generalized seismicconceptual design ideas in the codes of China, USA and Europe, it is raised thatthe seismic conceptual design ideas, especially the “generalized seismicconceptual design” ideas are the important driving forces for the developmentof the seismic design codes, which provides a new approach for developingmore reasonable and efficient generalized seismic conceptual design ideas andimproving the levels of seismic design codes.