单元式高层住宅楼梯间设计探讨

分析了剪刀式楼梯间和独立式楼梯间的特点,以及在单元式高层住宅设计中的应用,结合《规范》,对某些条文提出了见解。     

岩石非线性黏弹塑性流变模型(河海模型)及其应用

通过将作者提出的非线性黏塑性体与五元件线性黏弹性模犁串联，建立一个新的岩石非线性黏弹塑性流变模犁（河海模型），该流变模型可以充分反映岩石的加速流变特性。推导了岩石在恒应力与恒应变情况下的流变方程，从理论上对岩石非线性蠕变和松弛特性进行分析，同时利用在岩石流变倒服仪上扶得的蠕变全程试验曲线，对提出的非线性黏弹塑性流变模型进行充分验证，试验曲线与非线性流变模型的比较，显示了所建流变模型的正确性与合理性。基于提出的岩石非线性黏弹塑性流变模犁，推导该非线性流变模型在三维条件下的中心差分格式，采用FLAC^3D所提供的二次开发程序接口，研制岩石非线性流变数值程序，同时通过一个单轴压缩算例，进一步验证提出的非线性流变模型的正确性与合理性。采用研制的非线性流变数值程序，对锦屏一级水电站坝基岩石工程进行三维流变数值模拟，分析结果为锦屏一级水电站坝基岩石工程的长期稳定与安全性提供了合理建议与评价。     

《钢结构设计规范》(GB 50017-2003)应用中的几个问题

《钢结构设计规范》(GB 50017-2003)施行两年以来,在应用过程中提出了一些问题。就所接触到的问题陈述了个人的见解。问题包括:T形截面的梁端加劲肋的稳定计算、箱形截面轴心压杆的壁板宽厚比限值和超过限值时的有效宽度、框架二阶分析所涉及的重力荷载和柱压力、对接焊缝的强度设计值。     

莆田南门大酒店超限高层结构设计

本文介绍了莆田南门大酒店高位转换的超限高层结构设计,详述了本工程的结构设计与计算分析,重点介绍了梁式转换层的设计。     

现阶段建设工程工程量计价规范计价模式探讨

对工程量清单和工程量清单计价模式及其优点进行了介绍,阐述了工程量清单计价模式实施以来存在的问题,并提出了完善工程量清单计价的建议,以期使工程量清单计价模式更好地发挥规范招标投标活动,有效控制造价的作用。     

某超限底框砌体结构抗震加固设计

对于平面规则的超限底框砌体建筑,该文提出改变结构体系加固法,通过在局部墙体增设钢筋网片混凝土面层,局部设置混凝土剪力墙和框架柱,部分墙体在楼层处增设钢拉梁,形成广义框架-核心筒结构,不仅满足抗震要求,而且最大限度减少入户施工。该方法可为同类工程提供借鉴和参考。     

Sustainability assessment of dwellings – a comparison of methodologies

Building sustainability assessment tools (BSATs) aim to promote and rank the sustainability of building stock. This paper makes a deep comparative analysis on how dwellings are evaluated by five BSAT and one performance-based design tool. The comparison is based on: (i) the purpose of assessment; (ii) sustainability dimensions considered; (iii) indicators addressed; (iv) life cycle phases considered by the indicators; (v) type of indicators; (vi) measurements; (vii) aggregation processes; and (vii) life cycle phases during which the assessment was carried out. The evaluation showed that the scope of BSAT varies significantly as well as the life cycle phases addressed in the assessment. Financial issues are often excluded from the assessment. None of the schemes is totally quantitative or qualitative in their measurement system; all have different types of indicators and different ways to assess them. This research provides researchers and stakeholders with important inside knowledge on the tools that allow the development and construction of more sustainable buildings.     

Optimum model extent for numerical simulation of tunnel inflow in fractured rock

The objective of this study is the introduction of an optimum model extent in discontinuous rock masses for tunnel inflow assessment using numerical models. Tunnel groundwater inflow is an important problem in tunneling, and numerical simulation is widely used for estimating the amount of tunnel inflow. An adequate size of the model domain is of very high importance when using such models. On the one hand, if the tunnel boundary is too close to the outer model boundary, the simulated inflow rate into the tunnel is significantly overestimated (which will be shown in the present study). On the other hand, if the model domain is very large, models may become “unhandy”, and simulations become very expensive with respect to computer memory and CPU. In this technical note, an approach is presented that derives an optimum model extent for numerical simulation of tunnel inflow in fractured rock. The approach uses the two-dimensional universal distinct element code (UDEC). The impact of different model parameters, such as tunnel radius, groundwater level, joint spacing, joint dip/dip direction and joint aperture on the optimum model extent has been evaluated. Based on the results, an optimum model extent chart is presented that allows modelers a quick determination of the optimum model extent as a function of the most significant parameters, which are the tunnel depth under the groundwater level, tunnel radius and joint spacing.     

数字电视的离散余弦变换编码算法

在图像信息的传递中,常用到离散余弦(DCT)编码.讨论了DCT编码的基本算法,并以8×8DCT变换矩阵为例来说明问题,特别是对图像信号奇异值分解的数学原理及其特性给出了较为详尽的解,并指出用光栅扫描顺序测算各块的标准差过程中,当块标准差小于设定值时,可采用DCT编码.     

美国AISC《建筑和桥梁钢结构应用标准法规》介绍(Ⅱ)

2000年3月7日美国钢结构协会(AISC)和AISC规范委员会正式批准发布《建筑和桥梁钢结构应用标准法规》。该法规是一个指导性标准,本文对这一法规进行了介绍。本文是第二部分。