Reliability-Based System Factor for Serviceability Design of Wood Floors

A structural analysis model for parallel-member wood joist floors is developed that includes the effect of component creep. Viscoelastic material models are calibrated using the data from a recently completed experimental program conducted as part of this overall study. Using this system model, deflection serviceability reliability analyses of parallel-member wood systems, including the effects of creep deformation, are conducted. Stochastic load models are used to simulate the time-varying nature of applied loads. Multiple limit state definitions for deflection serviceability of parallel-member wood floors are considered. Monte Carlo simulation is used to evaluate limit state probabilities. Reliability indices for current serviceability design provisions are also evaluated, and a serviceability system factor for Load and Resistance Factor Design (LRFD) is recommended

Compliance and Verification of Standards and Labeling Programs in China: Lessons Learned

After implementing several energy efficiency standards and labels (30 products covered by MEPS, 50 products covered by voluntary labels and 19 products by mandatory labels), the China National Institute of Standardization (CNIS) is now implementing verification and compliance mechanism to ensure that the energy information of labeled products comply with the requirements of their labels. CNIS is doing so by organizing check testing on a random basis for room air-conditioners, refrigerators, motors, heaters, computer displays, ovens, and self -ballasted lamps. The purpose of the check testing is to understand the implementation of the Chinese labeling scheme and help local authorities establishing effective compliance mechanisms. In addition, to ensure robustness and consistency of testing results, CNIS has coordinated a round robin testing for room air conditioners. Eight laboratories (Chinese (6), Australian (1) and Japanese (1)) have been involved in the round robin testing and tests were performed on four sets of samples selected from manufacturer's production line. This paper describes the methodology used in undertaking both check and round robin testing, provides analysis of testing results and reports on the findings. The analysis of both check and round robin testing demonstrated the benefits of a regularized verification and monitoring system for both laboratories and products such as (i) identifying the possible deviations between laboratories to correct them, (ii) improving the quality of testing facilities, (iii) ensuring the accuracy and reliability of energy label information in order to strength the social credibility of the labeling program and the enforcement mechanism in place

Governing Yield Modes for Common Bolted and Nailed Wood Connections

Connections in wood structures are important when designing for ductility. The 1997 Uniform Building Code has taken this into consideration when designating wind and earthquake load duration factors for connections. Factors of 1.6 or 1.33 may be applied to the connection strength, depending on the type of yield mode exhibited by the connection, which may be determined from the yield limit equations supplied in the National Design Specification for Wood Construction (NDS). The NDS provides the designer with multiple tables containing capacities for various common connections. Unfortunately, yield modes are not published along with tabulated capacities. Therefore, the designer must carry out potentially cumbersome calculations using the NDS yield limit equations simply to determine the governing yield mode before an appropriate Uniform Building Code load duration factor can be applied. In this paper, several NDS tables are extended to include capacity and yield mode, smaller side member thickness configurations are added to the existing nail/spike tables, and a useful toe-nail table is provided. The overall purpose of these tables is to accelerate the design process by eliminating time-consuming calculations

Efficacy of Interactive Internet-Based Education in Structural Timber Design

While traditional teaching methods (e.g., real-time, synchronous lectures) have proven effective for training future engineers, the Internet provides an avenue to reinforce the material and augment student learning, comprehension, and retention of material. This paper presents the integration and assessment of a library of interactive instructional modules specifically for a senior-level undergraduate elective course in civil engineering. An ongoing, comprehensive assessment process was implemented in the fall 1999 semester. The results of this quantitative assessment indicate that the use of well designed and pedagogically sound Internet-based supplemental modules provide students with a better understanding of course material. However, when Internet-based content does not promote critical thinking, little increase in the student performance and understanding of the material is realized. Interactive Web-based instruction should not be viewed as a “replacement” to traditional instruction, but rather a tool that provides a broader and more dynamic environment for students with a variety of learning styles

Creep and Creep-Recovery Models for Wood Under High Stress Levels

Forty small clear southern pine specimens were loaded under third-point bending to examine creep and creep-recovery behavior for wood under high stress levels. Stress levels of between 69% and 91% of the predicted static strength were applied for 23 h with 1 h allowed for recovery, and the resulting deflection vs. time behavior was studied. The experimental creep and creep-recovery behavior was modeled using modified power law functions. The results indicate that these functions provide the best fit to both primary and secondary experimental data. The empirical models can be used to simulate the viscoelastic behavior of wood under high stress levels. The simulation will provide a useful tool in future studies to examine duration-of-load (DOL) effect, which is one of the more important factors in wood structural design

Status of the Local Enforcement of Energy Efficiency Standards and Labeling Program in China

As part of its commitment to promoting and improving the local enforcement of appliance energy efficiency standards and labeling, the China National Institute of Standardization (CNIS) launched the National and Local Enforcement of Energy Efficiency Standards and Labeling project on August 14, 2009. The project’s short-term goal is to expand the effort to improve enforcement of standards and labeling requirements to the entire country within three years, with a long-term goal of perfecting overall enforcement. For this project, Jiangsu, Shandong, Sichuan and Shanghai were selected as pilot locations. This report provides information on the local enforcement project’s recent background, activities and results as well as comparison to previous rounds of check-testing in 2006 and 2007. In addition, the report also offers evaluation on the achievement and weaknesses in the local enforcement scheme and recommendations. The results demonstrate both improvement and some backsliding. Enforcement schemes are in place in all target cities and applicable national standards and regulations were followed as the basis for local check testing. Check testing results show in general high labeling compliance across regions with 100% compliance for five products, including full compliance for all three products tested in Jiangsu province and two out of three products tested in Shandong province. Program results also identified key weaknesses in labeling compliance in Sichuan as well as in the efficiency standards compliance levels for small and medium three-phase asynchronous motors and self-ballasted fluorescent lamps. For example, compliance for the same product ranged from as low as 40% to 100% with mixed results for products that had been tested in previous rounds. For refrigerators, in particular, the efficiency standards compliance rate exhibited a wider range of 50% to 100%, and the average rate across all tested models also dropped from 96% in 2007 to 63%, possibly due to the implementation of newly strengthened efficiency standards in 2009. Areas for improvement include: Greater awareness at the local level to ensure that all manufacturers register their products with the label certification project and to minimize their resistance to inspections; improvement of the product sampling methodology to include representative testing of both large and small manufacturers and greater standardization of testing tools and procedures; and continued improvement in local enforcement efforts

Inventory of China's Energy-Related CO2 Emissions in 2008

Although China became the world's largest emitter of energy-related CO{sub 2} emissions in 2007, China does not publish annual estimates of CO{sub 2} emissions and most published estimates of China's emissions have been done by other international organizations. Undertaken at the request of the Energy Information Administration (EIA) of the US Department of Energy, this study examines the feasibility of applying the EIA emissions inventory methodology to estimate China's emissions from published Chinese data. Besides serving as a proof of concept, this study also helps develop a consistent and transparent method for estimating China's CO{sub 2} emissions using an Excel model and identified China-specific data issues and areas for improvement. This study takes a core set of data from the energy balances published in the China Energy Statistical Yearbook 2009 and China Petrochemical Corporation Yearbook 2009 and applies the EIA's eight-step methodology to estimate China's 2008 CO{sub 2} emissions. First, China's primary and secondary fuel types and consumption by end use are determined with slight discrepancies identified between the two data sources and inconsistencies in product categorization with the EIA. Second, energy consumption data are adjusted to eliminate double counting in the four potential areas identified by EIA; consumption data from China's Special Administrative Regions are not included. Physical fuel units are then converted to energy equivalents using China's standard energy measure of coal equivalent (1 kilogram = 29.27 MJ) and IPCC carbon emissions coefficients are used to calculate each fuel's carbon content. Next, carbon sequestration is estimated following EIA conventions for other petroleum products and non-energy use of secondary fuels. Emissions from international bunker fuels are also subtracted under the 'reference' calculation of estimating apparent energy consumption by fuel type and the 'sectoral' calculation of summing emissions across end-use sectors. Adjustments for the China-specific conventions of reporting foreign bunkers and domestic bunkers fueling abroad are made following IPCC definitions of international bunkers and EIA reporting conventions, while the sequestration of carbon in carbon steel is included as an additional adjustment. Under the sectoral approach, fuel consumption of bunkers and other transformation losses as well as gasoline consumption are reallocated to conform to EIA sectoral reporting conventions. To the extent possible, this study relies on official energy data from primary sources. A limited number of secondary sources were consulted to provide insight into the nature of consumption of some products and to guide the analysis of carbon sequestered in steel. Beyond these, however, the study avoided trying to estimate figures where directly unavailable, such as natural gas flaring. As a result, the basic calculations should be repeatable for other years with the core set of data from National Bureau of Statistics and Sinopec (or a similarly authoritative source of oil product data). This study estimates China's total energy-related CO{sub 2} emissions in 2008 to be 6666 Mt CO{sub 2}, including 234.6 Mt of non-fuel CO{sub 2} emissions and 154 Mt of sequestered CO{sub 2}. Bunker fuel emissions in 2008 totaled 15.9 Mt CO{sub 2}, but this figure is underestimated because fuel use by Chinese ship and planes for international transportation and military bunkers are not included. Of emissions related to energy consumption, 82% is from coal consumption, 15% from petroleum and 3% from natural gas. From the sectoral approach, industry had the largest share of China's energy-related CO{sub 2} emissions with 72%, followed by residential at 11%, transport and telecommunications at 8%, and the other four (commerce, agriculture, construction and other public) sectors having a combined share of 9%. Thermal electricity and (purchased) heat (to a lesser degree) are major sources of fuel consumption behind sectoral emissions, responsible for 2533 Mt CO2 and 321 Mt CO{sub 2}, respectively. The 2008 emissions estimated for China in this study falls within the range of other international estimates, and suggests that the EIA methodology can be adopted to estimate China's emissions if the proper adjustments are made. While these results are helpful in understanding China's annual emissions, several key areas of data challenges affect the accuracy of this estimate. Industrial process-based emissions - an important source of emissions given China's industry-intensive economy and size of its cement sector - have not been included in this calculation and could be the focus of further model refinement. The accuracy of the Chinese emissions estimate can be further improved by addressing two unreported international bunker categories and developing China-specific carbon sequestration coefficients for non-fuel use energy products

China Refrigerator Information Label: Specification Development and Potential Impact

In the last five years, China's refrigerator market has grown rapidly, and now urban markets are showing signs of saturation, with ownership rates in urban households reaching 92%. Rural markets continue to grow from a much lower base. As a result of this growth, the Chinese government in 2006 decided to revise the refrigerator standards and its associated efficiency grades for the mandatory energy information label. In the Chinese standards process, the efficiency grades for the information label are tied to the minimum standards. Work on the minimum standards revision began in 2006 and continued through the first half of 2007, when the draft standard was completed under the direction of the China National Institute of Standardization (CNIS). Development of the information label grades required consideration of stakeholder input, continuity with the previous grade classification, ease of implementation, and potential impacts on the market. In this process, CLASP, with the support of METI/IEEJ, collaborated with CNIS to develop the efficiency grades, providing technical input to the process, comment and advice on particular technical issues, and evaluation of the results. After three months of effort and three drafts of the final grade specifications, this work was completed. In addition, in order to effectively evaluate the impact of the label on China's market, CLASP further provided assistance to CNIS to collect data on both the efficiency distribution and product volume distribution of refrigerators on the market. The new information label thresholds to be implemented in 2008 maintain the approach first adopted in 2005 of establishing efficiency levels relative to the minimum standard, but increased the related required efficiency levels by 20% over those established in 2003 and implemented in 2005. The focus of improvement was on the standard refrigerator/freezer (class 5), which constitutes the bulk of the Chinese market. Indeed, the new requirements to achieve grade 1 on the label are now virtually as stringent as those for US Energy Star-qualified or EU A-grade refrigerators. When the energy information label went into effect in March 2005, refrigerator manufacturers were required to display their declared level of efficiency on the label and report it to the China Energy Label Center (CELC), a newly established unit of CNIS responsible for label program management. Because of the visible nature of the label, it was found, through a METI/IEEJ-supported study, that MEPS non-compliance dropped from 4% to zero after the label became mandatory, and that the percentage of higher-grade refrigerators increased. This suggests that the label itself does have potential for shifting the market to higher-efficiency models (Lin 2007). One challenge, however, of assessing this potential impact is the lack of a comprehensive baseline of market efficiency and a program to evaluate the market impact on a yearly basis. As a result, the impact evaluation in this study draws upon the market transformation experience of the related EU energy information label, for which quantitative assessments of its market impact exist. By assuming a parallel process unfolding in China, it is possible to look at the potential impact of the label to 2020. The results of the analysis demonstrates that a robust market transformation program in China focused on the energy information label could save substantial amounts of electricity by 2020, totaling 16.4 TWh annually by that year, compared to a case in which the efficiency distribution of refrigerators was frozen at the 2007 level. Remarkably, the impact of a successful market transformation program with the label would essentially flatten the consumption of electricity for refrigerator use throughout most of the next decade, despite the expectations of continued growth in total stock by nearly 190 million units. At the end of this period, total consumption begins to rise again, as the least efficient of the units have been mostly removed from the market. Such a level of savings would reduce CO{sub 2}, SO{sub 2}, NO{sub x} and particulate matter as well. Cumulatively to 2020, CO{sub 2} emissions would decline by 67.5 million tonnes; SO{sub 2} by 368,000 tonnes, NO{sub x} by 263,000 tonnes, and particulate matter by 1.6 million tonnes. To ensure that the information label can provide the basis for such a market transformation, additional focus should be paid to regular monitoring and supervision of the label, expansion of market survey and information collection efforts, building recognition and awareness of the benefits of buying higher-ranked models, and development of programs of consumer education and promotion in conjunction with retailers