The first crack in the unretrofitted adobe structure occurred during the test at an acceleration level of 0.17 g and input displacement of 5.8 cm, and, owing to the loss of structural integrity, separation of the out-of-plane walls occurred. The level at which the elastic, first cracking, behavior of unretrofitted adobe building walls occurs is not usually significant because the walls of most historic buildings could already have some crack damage from water, earthquakes, or foundation settlement. During subsequent tests, many additional cracks appeared in all walls, and after the final dynamic test, the model was heavily damaged. Development of almost vertical and horizontal cracks was evident in the out-of-plane walls. After the final test the model suffered large nonlinear damage that resulted in the collapse of the east gable end wall (see fig. 8).
Following the emergence of modern construction methods in which steel and reinforced concrete replaced brick and stone as principal building materials, structural designs were developed that could withstand environmental loads (wind and earthquake) and perform in a relatively predictable and acceptable way. Steel and reinforced concrete are ductile materials that have linear elastic properties and good postelastic strength characteristics. After yielding, these materials maintain most of their strength while undergoing substantial plastic deformations, and they can be analyzed with reasonable accuracy using analytic or computational methods. In contrast, after cracks are initiated, the behavior of brittle, unreinforced materials, such as stone, brick, or adobe, is extremely difficult to predict even with today's advanced computational capabilities. Even if computational results could be generated, the results would not be accurate. In a brittle material, once yielding occurs, cracks develop and there is a complete loss of tensile strength. After cracks have developed, the seismic behavior of adobe buildings is dominated by the interactions among large, cracked sections of the walls that rock out-of-plane and collide or rub against each other in-plane.
adobe director 12 full crack
Reinforced concrete bond beams, placed at the tops of walls below the roof, are often recommended for the upgrading of existing adobe buildings (California State Historical Building Code 1999). The function of bond beams is to provide lateral support and continuity at the tops of the walls. However, the installation of a bond beam usually requires the removal of the roof system, a very invasive and destructive procedure. The design of bond beams is often based upon elastic design criteria, which result in a very stiff bond beam. After cracks in the adobe walls develop during an earthquake, the stiffness of the bond beam may exceed the stiffness of the walls by 2 or 3 orders of magnitude. Adobe walls have been observed to pull out from underneath bond beams during an earthquake due to the difference in stiffness between the bond beam and the cracked wall sections and the lack of a positive connection between the bond beam and the adobe walls.
Structural stability is the fundamental requirement for the adequate performance of adobe buildings during large earthquakes and should be the principal guide for designing appropriate retrofit measures. The walls of adobe buildings will crack during moderate to large earthquakes because adobe walls are massive and both the adobe brick and adobe mortar are low-strength materials. The massive walls respond to the large inertial forces that result from seismic ground accelerations, and they have relatively little strength to resist these forces. After cracks have developed, it is essential that the cracked elements of the structure remain in place and be able to carry vertical loads.
(PhysOrg.com) -- The proportion of women who lead California’s largest companies is growing at such a slow pace that it will take more than a century for women business leaders to achieve parity with men, a UC Davis study has found. googletag.cmd.push(function() googletag.display('div-gpt-ad-1449240174198-2'); ); The seventh annual UC Davis Study of California Women Business Leaders found that women still occupy fewer than one in 10 of the top posts at the 400 largest public companies headquartered in California — a rate that has improved by just 0.2 percent annually.The study also showed that more than a third of California’s corporate giants — including household names like Adobe Systems Inc., Hansen Natural Corp. and Skechers USA Inc. — had no women among their highest-paid executives or board directors.Together, the companies in the study represent nearly $3 trillion in shareholder value.“Having more women involved at the highest levels of business management and corporate governance brings greater diversity of thinking styles, industry knowledge, educational background and career experience, yet we continue to find disappointingly small proportions of women in leadership roles in what is widely regarded as a progressive, trend-setting state,” said Steven Currall, dean of the UC Davis Graduate School of Management, which releases the study each year.“There are plenty of qualified women to hire and promote, but the vast majority of the 400 largest public companies in the state don’t seem to recognize that. Our mission is to change that,” Currall said.The survey is the only one of its kind to focus on gender equity in the boardrooms and executive suites of corporate California.The study looked at the five highest-paid executives for each company, also called “named executive officers,” as reported to the Securities and Exchange Commission. The study examined filing data available as of June 2011. The 400 companies were selected based on market capitalization.Key findings of this year’s study:• Overall, women held 9.7 percent of board seats and highest-paid executive positions — similar to last year’s findings.• More than one-third, or 136 (34 percent), of the 400 companies had no women among their board directors or highest-paid executives.• Women accounted for 9.2 percent of the 1,925 highest-paid executives reported by the 400 companies.• Women held 10 percent of the 3,224 board seats in the 400 companies.• No company had an all-female board or executive management team.• No company had both a gender-balanced board and executive management team.• More than 40 percent of the 136 companies that tied for last place, with no women executives or board members, are high-tech companies.• Only 13 public companies had a woman CEO, down from 16 in 2010.• The number of women CFOs increased from 35 last year to 45 this year — a 28.6 percent increase. (adsbygoogle = window.adsbygoogle []).push(); For the second year in a row, the company with the best gender balance was Brisbane-based bebe stores inc. The women’s apparel company reported that women held 40 percent of the highest-paid executive and board director seats. The 2011 study was released at a news conference here at bebe stores.“We celebrate women and diversity every day,” said Manny Mashouf, founder and chairman of bebe stores. “Our brands and marketing speak to women, their independence, power and confidence.”Southern California-based Wet Seal Inc., also a women’s apparel company, showed a dramatic rise in its ranking. Last year, the company had only one woman among its highest-paid executives and board directors. This year, Wet Seal tied for second place, with women holding 36.4 percent of the top positions. In addition, Wet Seal was among the 13 public companies statewide with a woman CEO.The San Francisco Bay Area is home to 208 of the companies surveyed, while 178 are based in Southern CaliforniaOrange County — home of the No. 2-ranked Wet Seal — had the lowest overall percentage of women in top leadership positions of any county in the state.Santa Clara County had the second-lowest percentage.San Francisco and San Mateo counties had the highest percentage of women in top leadership positions.Companies in the retail and wholesale sector were the most likely to have at least one woman executive among the highest-paid. Semiconductor and software companies continued to rank at the bottom, with women holding 3 percent, or fewer than one in 28, of the highest-paid executive positions.UC Davis partnered on this year’s study with Watermark, a Bay Area-based nonprofit that offers programs for executive women. Previous studies were conducted with the Forum for Women Entrepreneurs and Executives, Watermark’s forerunner.“Women are the next global economy. They make up a majority of the work force in nine of the 10 occupations that will add the most jobs in the next eight years," said Marilyn Nagel, CEO of Watermark. “Despite this, women still represent a significant minority on boards. There are many qualified women capable of serving on boards who are not currently getting those roles.”To download a full copy of the study, including industry-by-industry and county-by-county statistics, visit www.gsm.ucdavis.edu/census . Provided byUniversity of California 2ff7e9595c
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