Benchmarking Studies on Construction Safety Management in China

This paper presents information by which to measure safety management performance on construction sites. In China, the conventional construction safety benchmarking approach is to assess safety performance by evaluating the physical safety conditions on site as well as the accident records, while no attention has been paid to the management factors that influence site safety. This paper is to identify the key factors that influence safety management and to develop a method for measuring safety management performance on construction sites. Based on the survey and interview data collected on safety management factors in 82 construction projects in China, the safety management index as a means to evaluate real-time safety management performance by measuring key management factors was developed. The quantified factors were compared with the commonly accepted physical safety performance index, which was derived from inspection records of physical safety conditions, accident rates, and the satisfaction of the project management team. Multifactor linear regression was conducted and the result indicates that safety management performance on site is closely related to organizational factors, economic factors, and factors related to the relationship between management and labor on site. Based on this benchmarking study, a practical safety assessment method was developed and then implemented on six construction projects. The results show that this method can be an effective tool to evaluate safety management on construction projects.     

Benchmark Problem for Response Control of Wind-Excited Tall Buildings

This paper presents an overview and problem definition of a benchmark problem for the response control of wind-excited tall buildings. The building considered is a 76-story 306 m concrete office tower proposed for the city of Melbourne, Australia. The building is slender with a height to width ratio of 7.3; hence, it is wind sensitive. Wind tunnel tests for such a 76-story building model have been conducted at the University of Sydney and the results of across-wind data are used in the present benchmark problem. Either active, semiactive, or passive control systems can be installed in the building to reduce the wind response, although only an active control sample problem has been worked out to illustrate the control design. In the case of active control systems, either an active tuned mass damper or an active mass driver can be installed on the top floor. In the case of passive or semiactive systems, such as viscous dampers, viscoelastic dampers, electrorheological, or magnetorheological dampers, etc., control devices can be installed in selected story units. Control constraints and evaluation criteria are presented for the design problem. A simulation program based on the linear quadratic Gaussian technique has been developed and made available for the comparison of the performance of various control strategies.     

油气混合式减振器动态特性研究

以SR20飞机前起落架减振器为例，通过逆向建模的方法建立减振器的三维模型，并使用Fluent进行流体仿真，通过台架试验的方法验证仿真模型的正确性，在此基础上改变减振器常通孔直径、导油槽宽度、导油槽深度、活塞杆直径和单向活门直径来探究其结构参数变化对减振器动态性能的影响。结果表明：常通孔直径相较于其他4个参数对减振器的动态性能影响较小；导油槽的流通面积对于减振器的动态性能影响较大，其中导油槽宽度的影响大于导油槽深度；随着导油槽流通面积的减少，减振器中位复原阻尼力和中位压缩阻尼力变大，且变化明显；活塞杆直径减小，减振器阻尼力变大；单向活门直径减小，减振器复原阻尼力不变，中位压缩阻尼力变大。     

祝家排土场堆浸排土台阶高度优化研究

德兴铜矿成功利用含菌的酸性水浸出含铜废石中的铜，经过几年生产实践，目前还存在浸出液含铜浓度不高，产生电铜量少和成本较高等问题。为此，以不同台阶高度铜的浸出率和不同台阶高度的运输功、排出成本为基础，从提高浸出率及降低排土成本两方面研究了排土台阶高度。研究结果表明，在排土台阶高度为10m、20m、30m的情况下，其排土成本以10m台阶高度最大，20m、30m的成本变化不大。考虑堆浸时的排土台阶高度以10～20m为最佳。     

台达工控产品在微拉退火设备控制系统中的应用

微丝在纺织行业中有广泛的应用，本文针对微拉退火设备存在的灵活差等控制问题，采用台达工控套件产品对微拉退火设备控制系统进行了改造。系统投运效果表明设计是成功的。     

Management of Construction Firm Performance Using Benchmarking

In today’s highly competitive construction industry, there is a critical need for managers to continuously improve their firm’s efficiency and effectiveness. More specifically, managers need to know which performance measures are most critical in determining their firm’s overall success. Benchmarking, when done properly, can accurately identify both successful companies and the underlying reasons for their success. However, rigorous benchmarking within the construction industry still remains an embryonic field. This paper analyzes and critiques both the performance measures and metrics used traditionally in the construction industry and the benchmarking models developed to date for the industry. Based on the results of this analysis, benchmarking models using data envelope analysis are proposed that offer significant improvements over current models. The proposed models measure construction firm performance on a company-wide basis, foster trade-off analyses among various performance metrics, and tie the resources expended by construction firms to how well those firms perform overall. The models also provide managers guidance in determining how specific company resources can be reallocated to improve overall company performance.     

Comparable Performance Measurement System for Construction Companies

The construction industry has mainly relied on financially focused performance measurements, and studies on performance measurement systems (PMSs) have been carried out at the project level. However, recently, the demand for performance evaluation and management at the company level has increased. A few previous efforts have aimed to develop a conceptual framework for company performance, but there have been few follow-up studies. From this perspective, we have developed an implementation model and practical methodology to measure and compare the performance of construction companies. First, our thorough qualitative and quantitative analysis was used to develop a set of indicators for performance measurement, and an analysis of the relative weightings of the indicators was carried out. Second, we calculated the performance score of construction companies using a study of 34 Korean construction companies. Finally, we carried out a performance evaluation and system analysis using the calculated performance scores and identified practical issues for the implementation of our PMS. Using the results of our analytical processes identified in this work, further research is suggested.     

新型复合捕收剂TA在湖南某钨矿浮选工艺的应用

湖南某钨矿采用重选法回收白钨矿,其分选效果很差。经试验研究,确定采用先浮硫化矿,再加入Na2CO3、Na2S iO3和高效复合捕收剂TA进行白钨粗选,白钨粗精矿添加改性Na2S iO3和高效复合捕收剂TA进行加温精选的工艺流程。最终小型试验获得WO3品位70.19%、回收率82.86%的白钨精矿,扩大连续试验获得WO3品位65.41%、回收率81.12%的白钨精矿。结果表明,选用新型复合捕收剂TA,是提高选矿技术经济指标的关键。     

深水炮孔爆破效果的优化技术

露天矿开采深度逐年增加,炮孔内的渗水越来越不容忽视。分析了炮孔内的水对爆破效果的影响,探讨了技术解决的途径。结合北京首钢铁矿的实际情况,利用水介质的不可压缩性和良好的能量传递性,采用大孔距布孔和爆破综合优化技术,提高了延米爆破量,改善了爆破效果,为探索深水炮孔的高效爆破技术取得了有意义的成果。     

水电工程施工梯段爆破计算机仿真及应用

根据岩体动载微损伤和岩体天然裂隙统计理论建立了适用于水电工程施工梯段爆破级配预报的计算机模型。使用该模型成功地预报了某水电站面板堆石坝的爆破级配。计算机模拟结果证实采用该模型可以改善爆破参数 ,节省大量爆破试验经费和缩短爆破试验时间