节地住宅探讨

随着我国的人口发展，住宅建设大量增加，用地与人口的矛盾，使住宅节地问题显得非常突出。未来居住小区的节地将是一个多维的概念，应该从环境可持续发展出发加以解决，它将关系到住宅建设的根本出路。通过量化分析和实例分析，论述了部分节约用地的有效措施，并在此理论的指导下，做了若干探索性方案。     

Structural analysis of assemblages of thin-walled members

A matrix method for the analysis of structural systems composed of thin-walled members is presented. The matrix displacement analysis includes the effects of thin-walled non-uniform torsion theory, cross-section asymmetry, eccentric restraint as well as joint types peculiar to thin-walled members. The method is used for a prediction of the elastic behaviour of a set of representative test frames. The test frames were pitched-roof portals constructed from channel sections bent about their major-axis and supported by eccentric restraints simulating purlins and girts.     

城市灭火救援力量成本效益合算导则分析

从经济学的角度出发，以上海市为例采用成本效益分析方法，对灭火救援力量成本和效益进行了定量衡量和分析，计算出其效益成本比率，并对成本效益合算导则的确立过程进行探讨。     

Precision of in-place concrete strenghts predicted using core strength correction factors obtained by weighted regression analysis

A two-step method for converting a concrete core compression test result to the in-place strength of the corresponding volume of concrete is presented. The strength of a non-standard core is first converted to the equivalent strength of a standard core, and then the standard core strength is converted to the equivalent in-place strength. Strength correction factors required for these conversions, obtained from weighted linear and nonlinear regression analyses presented elsewhere, are summarized. The accuracy of the predicted in-place strength is affected by the inherent error of the core strength measurement itself, and by the uncertainty of the various strength correction factors. It is shown that confidence intervals on the estimates of the strength correction factors obtained by regression analysis underestimate the true model error because the underlying models are imperfect. Instead, the accuracy of the strength correction factors is determined by a weighted regression analysis of ratios of observed-to-predicted values which accounts for the non-uniform variances of the dependent and independent variables. The coefficient of variation of the in-place strength predicted from a test of a 100 or 150 mm diameter core is between 4 and 5.5.%. If the in-place strength is predicted from a test of a 50 mm diameter core, the coefficient of variation of the predicted in-place strength is approximately 12.5%. These error estimates do not account for possible variation of in-place strength throughout the volume of the element being cored.     

某住宅楼桩基工程事故分析与处理

本文介绍某住宅楼桩基工程质量事故原因分析，并根据桩土共同受力的原理，采用加宽承台并在承台下设砂垫层的方法，进行加固处理，效果较好。     

双塔双索面预应力混凝土斜拉桥的地震反应分析

重庆奉节长江公路大桥是一座双塔双索面预应力混凝土斜拉桥,为了解其在地震作用下反应特性,利用大型通用有限元软件 Ansys 对其进行了地震反应时程分析,总结了其在不同地震动输入下的反应特点,为同类桥梁抗震分析提供了一定的借鉴经验。     

Structural reliability software at the University of California, Berkeley

The paper provides an overview of three software for structural reliability analysis developed at the University of California, Berkeley. These are CalREL, which is a general-purpose structural reliability code written in FORTRAN; FERUM, which is a collection of Matlab^® files that can be used for structural reliability analysis in conjunction with simple finite element models; and OpenSees, which is an object-oriented code for nonlinear structural response simulation with reliability capabilities. Reliability analysis methods featured by these software include FORM, SORM, Monte Carlo simulation, and various importance sampling methods. In addition, variable importance and sensitivity measures are provided.     

The characterisation of friction stir welding process effects on stiffened panel buckling performance

The introduction of advanced welding methods as an alternative joining process to riveting in the manufacture of primary aircraft structure has the potential to realise reductions in both manufacturing costs and structural weight. However, welding processes can introduce undesirable residual stresses and distortions in the final fabricated components, as well as localised loss of mechanical properties at the weld joints. The aim of this research is to determine and characterise the key process effects of friction stir welding assembly methods on stiffened panel static strength performance. Utilising experimentally validated finite element modelling methods, it is demonstrated that welding induced residual stresses have a significant influence, and that collapse behaviour is less sensitive to advanced process effects and process effect magnitudes than panel initial buckling behaviour.     

Expansion of the US wildland–urban interface

For at least two decades, expansion of low-density residential development at the wildland–urban interface has been widely recognized as a primary factor influencing the management of US national forests. We estimate the location, extent, and trends in expansion of the wildland–urban interface (WUI) in the continental United States. We mapped the WUI by determining the intersection of housing density classes computed from refined US Census data with a map of wildfire hazards based on broad forest types using definitions of WUI from the Federal Register. Our methods allowed us to provide a more spatially precise estimation of the WUI that better reflects development patterns of interest to forest land managers. We defined three wildfire hazard classes based on vegetation type. “High” severity applies to vegetation types in which stand-replacing fires dominate both historical and recent fire regimes, e.g., lodgepole pine forest. “Low” severity applies where fuels and climate foster mostly low-intensity fires, e.g., aspen-birch forest. “High (historically low or variable)” applies to vegetation types in which fires historically were of low or variable intensity, but recently have often burned at high intensity because of a century of fire exclusion, e.g., southwestern ponderosa pine forest. In 2000, the WUI that includes a 3.2 km community protection zone occupied 465,614 km², and contained over 12.5 million housing units. This is an expansion of over 52% from 1970, and by 2030 the WUI is likely to expand to at least 513,670 km² with the greatest expansion occurring in the intermountain west states. Roughly 89% of the WUI is privately owned land and about 65% of the WUI occurs in high or high (historically low or variable) severity fire regime classes.     

Probabilistic Modelling in the Water Industry

The water authorities in England and Wales, which have now become water companies, recently had to provide anticipated costs for maintaining the water supply and sewerage systems over the next 20 years. Probabilistic models and statistical inference provide an opportunity to quantify the uncertainty in such exercises. Their use in a study undertaken by a water authority in the north-east of England is described and illustrated with interim data which were available at an early stage in the exercise.