Survey

SURVEY APPROACH AND PROCESS

The goal in performing a formal written survey was to achieve a more quantitative and consistent form of measuring and evaluating the changes in the Japanese construction industry than could have been derived from a series of isolated interviews. The written survey also allowed a wider range of individuals and companies to be reached than was practical in a series of one-on-one meetings. The ultimate goal was to identify the catalysts in the post-earthquake environment which led to changes in practice, and this required going beyond Question No. 1 to collecting data on a wide variety of issues related to technical decision-making, economic implications, and the expectations of building owners and the general public.

Two separate questionnaires were developed, with alternate pages in English and Japanese to allow the widest possible audience to be reached. The first questionnaire was targeted specifically at building designers and construction companies, with a total of 30 questions grouped into six categories: general issues, project-specific information, the design process, owner requirements and economics, regulatory and approval issues, and future trends. The second questionnaire was developed for a more general audience, including building owners, researchers, and regulators. This questionnaire contained a subset of 13 questions and did not include project-specific questions or questions regarding the design process.  With almost every question, ample room was provided for respondents to add their own opinions or comments.

It was recognized early in planning the survey that an exhaustive distribution (e.g. to all members of the Architectural Institute of Japan) was not possible, and it was not easy to identify a statistically representative subset of engineers or building owners. Instead, a list of approximately 120 individuals and firms was developed from the authors' personal contacts, recommendations from colleagues, members of industry associations, and academics involved in government design review committees. Questionnaires were mailed to this group of people first, and then the researchers distributed additional questionnaires during a visit to Japan. Several more questionnaires were distributed through third parties as well as at the annual meeting of the Japan Society for Seismic Isolation (JSSI). In general, the respondents were given one month to respond, although questionnaires continued to be returned for some months after the initial distribution. Of the approximately 150 questionnaires distributed, 63 people responded for a return rate of better than 40 percent; 32 of the "designer" questionnaires were returned, and 31 "owner/researcher" questionnaires were returned.

The second part of the data collection effort involved visits to a number of building sites, design offices, and research facilities in Japan. These one-on-one meetings allowed more in-depth discussion of the issues raised in the questionnaires, and provided the opportunity to follow-up on interesting tangents to the main conversation. The researchers attempted to work from a set of introductory questions, and then let the conversation proceed unscripted. Each meeting typically closed with Question No. 1, after all of the other issues had been discussed. More meaningful information was often gleaned from gatherings held after business hours as opposed to those which took place in the formal confines of company meeting rooms.

SURVEY RESULTS

This section highlights the response to a few of the more general questions. To view the complete survey results please see the paper.    

Questions 1 and 2:  In your opinion, what is the primary reason that the use of seismic isolation [Question 1] (energy dissipation/passive damping [Question 2]) has increased substantially since the Kobe earthquake?

Among all of the written questionnaires and interviews, the responses to the basic question of why isolation and damping have increased in use can be distilled into the following categories:

  • Increased public awareness of and demand for seismic safety that encompasses protection of life and property, particularly the structure and its contents ("Now, the general public knows the danger of earthquakes so they are requiring buildings with better safety").
  • Observed damage to buildings designed according to recent codes, and a critical view or sense of doubt regarding the reliability of traditional construction approaches ("... a gap between structural designers and [the] general public").
  • Proof of the maturity and effectiveness of the technologies (particularly for seismic isolation), by the performance of buildings in the Kobe and Northridge earthquakes ("Isolation has moved from the research stage to the... production stage").
  • Recommendations from engineering organizations and the Ministry of Construction ("For high-rise buildings, the evaluation committee of BCJ has a strong opinion to use new technologies").
  • The large promotional efforts of developers, construction companies, and designers ("... it was good advertisement for general contractors to obtain more clients").
  • A form of group behavior capitalizing on the anxiety felt by many after the earthquake ("... they are very much afraid of earthquake hazards").
  • People's fascination with new technologies and their desire to be early adopters ("the increase is the response to the demand for aseismically superior technologies").

Question 3:  In your opinion, how well educated is the general public on earthquake engineering and new technological advances (such as isolation and energy dissipation)?

There was general agreement among all respondents that the general public was more aware of seismic engineering after the Kobe earthquake because of the prevalence of reports on the damage and reconstruction efforts in the mass media. However, in qualitative terms, the general assessment of the public's knowledge was slightly better than "a little" on the sliding scale of possible responses, and many respondents suggested that public awareness had already waned in the three years since the Kobe earthquake. One respondent felt that the level of awareness likely correlated with experience of strong earthquakes. Several individuals indicated that the Kobe earthquake had focused attention on the lack of understanding of the implications of building codes, particularly the "misunderstanding that codes and regulations guarantee the safety of structures." It was suggested that damage criteria are understood by structural designers but "... are neither known to nor approved by society," and structural engineers should "tighten their relationship with society."

With respect to new technologies, many respondents believed that the general public was vaguely aware of the various approaches but tended to "blindly believe the seismic performance." One exception was in large cities, where some respondents felt that advertisements for condominiums and television commercials made people aware of seismic isolation, and rubber bearings in particular. One designer felt that company facilities managers, in particular, had changed their attitudes after the Kobe earthquake.