要在二分半地上做文章

时代的进步,首先是人们思想观念的.进步,只有人们思想观念的不断更新,才能推动时代的进步。由于历史的原因,人们的思想深处还根深蒂固地存在着宅宽院阔,一房大屋深的传统观念,对宅基地限制在二分半以内有抵触情绪,多占宅基,滥用土地的现象还十分严重的存在。再者由于传统的小农经济意识的影响,不但农民自身存在的小而全的思想,就是有组织的农居设计方案竞赛,也将小而全作为评选优秀方案的参评标准,明明     

乔家大院和雪岩故居营造之比较——论行商心态对民居建造的影响

商帮,是我国自古以来便有的一种经济现象,商人们由地缘结成联盟,生意场上同气连枝,守望相助,借助一种乡土情结来分割天下财富.其中最具代表性和传奇色彩的两支就是晋商和徽商,山西乔致庸和江南胡雪岩便是其中的翘楚. 晚清风云变幻,列强肆虐,民患频繁,社会正处在动荡的变迭时期,工商业的资本化和官僚化为商人们积累了富可敌国的财富,也为他们营造府第奠定了坚厚的物质基础.思潮的碰撞和商场上的机变,使手握重财的商人无法满足普通的高墙深院,他们开始打破道统,追求个性.     

好雨当春

黔阳古城往北,是一座崭新的黔城,它是今天洪文明的彩练,唱出冰心玉壶的承诺,擂起招贤纳才的江市的行政中心。新老黔城,仿佛一见如故的忘年战鼓,建设锦绣黔城,进而让洪江青山常驻,绿水长交,更像血肉相连的亲人,守望相助。因了黔阳古流,城乡富庶,人民安居乐业。     

解析文人建筑与商人建筑——书院与会馆建筑的比较研究

书院与会馆是两种不同类型的传统建筑,具有共性,又有鲜明的个性。本文对比研究两种建筑的异同,透过建筑表象,折射出文人建筑与商人建筑不同的人文内涵。土人修身养性,融于自然,追求雅趣：商人重义取利,融于社会,追求财富,不同的文化背景和价值取向,诱发不同的建筑观和审美情趣,渗透到建筑,使其蕴涵丰富的文化内容,呈现不同的风格和特色。校区文物建筑的保护与利用提出了自己的见解。     

魂牵梦绕铁道兵

简单、充实,黑白、葱茏的军旅岁月,令人追忆,一遍又一遍。一张张笑脸,一个个身影,质朴而坚毅,平实又伟岸,已经化作了座座丰碑,静立于岁月深处,须仰视。——编者2011年8月,我正式退休,我的职业生涯就此画上了一个圆满的句号。在家闲来无事,偶然翻起了几篇关于铁道兵的纪实文学,那朴实的语言,似曾相识的故事,让我不禁想起了自己的军旅岁月。1976年,我光荣参军,成为一名铁道兵。告别家人,     

为“塔”披上最美丽的衣裳——沈阳远大铝业工程有限公司发射塔幕墙施工侧记

2011年3月26日,河南广播电视发射塔试运行。蓝天白云下,发射塔灵秀,挺拔,五朵圆形花瓣组合而成的塔楼,由下至上逐层扩大,犹如缓缓开放的梅花,轻盈,秀美。外立面蓝黄相间的玻璃和不锈钢板,为发射塔粗犷的钢结构骨骼披上一袭华美的外衣。设计师巧妙构思,合理布局,使玻璃和不锈钢板相互掩映,相互衬托,将金属的质感和玻璃的轻盈完美地融为一体。     

云上天峨

朋友说,这水下,就是当年繁华一时的老向阳镇,我的家,我的老家,就在这水下了,祖上几代都是居住在这个老镇。他的话很自然,但声音和语气却似乎凝结在水面,似乎还要沉下水底,去触摸那些曾经的青砖黑瓦,和那些巷道里平滑的青石板……十年前,我经常与这位朋友在老向阳镇的半间小木屋里,举杯横对雨后的西山白云。而现在,他告诉我,曾经的西山,就是我们现在船边的这座小岛,而我们的游船刚划过的地方,或许就在当年的那些飘绕的云朵之上。     

红灯掩映,年华寂寞——晋商大院中的女性空间

正黛瓦青墙,漆黑的木门,锁住了生如夏花的芳华,围住了逝如冬雪的过往。朝阳初升的路上,渐渐响起了悠悠的调子,一段饱含啜泣的《走西口》传出很远,画面中离家的男人走得很慢,最后的一个转身,中间却是眼泪才能衡量的距离。女人止步,久久无语凝噎,只好回到用等待搭成的大院里,用回忆以候良人的归来。     

昌都新貌安康藏区——昌都市旧城改造纪实

西藏自治区昌都市以改善民生为目标,以改造旧城棚户区和治理非法私建为突破口,坚持规划先导,合理配置有限资源,集中优势力量,推动城市化进程,走出一条昌都特色的路子. 藏东明珠的华丽转身 昌都市,东接四川,北邻青海,是西藏第一面五星红旗升起的地方.65年前的10月,人民解放军解放了昌都,处于康巴藏区腹心地带的农奴翻身做了主人.65年来,昌都人民的居住环境变化翻天覆地.     

易在河南

伏羲,中华民族人文始祖,是我国古籍中记载的最早的王,所处时代约为新石器时代早期,他根据天地万物的变化,发明创造了八卦,成了中国古文字的发端,也结束了“结绳纪事”的历史。他又结绳为网,用来捕鸟打猎,并教会了人们渔猎的方法,发明了瑟,创作了《驾辨》曲子。他的活动,标志着中华文明的起始,也留下了大量神话传说。     

基于三变量控制的平板车行走驱动系统研究

由于发动机控制算法复杂、特性多变,在工程机械行业中一直没有解决发动机和液压系统的匹配控制问题,作业过程中完全由操作人员决定发动机的输出,这就导致输出动力过剩或者不够,造成浪费或者作业效率低的现状.为了解决这个问题将发动机也加入控制环中,从传统的只对液压泵一个变量进行闭环控制,变为对液压泵、液压马达、发动机三变量进行闭环控制.立足于平板车的行走驱动系统,主要对平板车行走作业重点分析,以优化系统性能,提高工作效率和机械性能为目标,利用SIMULINK建立三变量系统的数学模型,采用PID控制算法,经过仿真分析,找出参数优化调节规则,寻求三变量间的匹配运行.在仿真的基础上进行试验验证,为平板车产品的设计提供理论依据,对实现高效节能,降低能耗具有重要的现实意义.     

Management of bridges with shallow foundations exposed to local scour

Abstract

The Serbian road network includes a large portion of bridges with shallow foundations vulnerable to local scour as tragically demonstrated during the extreme flooding in May 2014. Currently, the bridge management procedures in Serbia and worldwide do not comprehensively account for a risk of bridge failure due to flooding and fail to provide sufficient information for the decision-making. Thus, a novel methodology for quantitative vulnerability assessment is suggested as a tool to identify the most vulnerable bridges in a network. Herein, the essential task is evaluation of the conditional probability of a bridge failure due to local scour in a flooding event of a certain magnitude. To apply this approach on a network level, there is a dire need to establish precise practice-ready guidelines on an optimal set of information to be used and/or collected in situ, which is discussed on an example of the Serbian bridge database. The vulnerability of a bridge to local scour may be used as a comprehensive indicator of a bridge performance in a flooding event. For a network level, the vulnerability maps with respect to flooding of different magnitudes will give road operators crucial information to apply adequate quality control plans to vulnerable bridges.     

Nonlinear analysis and reliability of metallic truss structures

The present study goes into the search for the safety domain of civil engineering structures. The objective is to show how a reliability-evaluation brought by a mechanical sizing can be obtained. For that purpose, it is necessary to have a mechanical model and a reliability model representing correctly the behavior of this type of structure.It is a question on one hand, to propose a formulation for the nonlinear calculation (mechanical nonlinearity) of the spatial structures in trusses, and on the other hand, to propose or to adapt a formulation and a modeling of the reliability. The principle of Hasofer-Lind can be applied, in first approach, for the reliability index estimation, scenarios and the probability of failure.The made check concerned metallic in truss structures. Finally, some structures are calculated using the method adapted by Hasofer-Lind to validate the probability approach of the reliability analysis.     

可持续发展战略的文化性转变？

论述了城市文化性作为一个长久被忽略的价值维度在城市可持续发展中的重要意义。文化是城市变革的催化剂,是城市精神、活力和吸引力的源泉。,当代的可持续发展概念将物质和技术作为核心,致使非物质文化遗产在城市发展过程中的破坏和缺失。作为城市集体记忆载体的城市公共空间,在传承城市文化方面具有特殊的意义。通过将城市文化、公共艺术与城市空间改造相结合,我们可以加强地域归属感,保护当地文化的多样性。以一种探索性的方式论述了文化性转变对于实现城市可持续性的合理性和必要性。对社会草根阶层生活方式、行为模式、文化标识的研究,能够帮助我们进一步理解城市的社会结构,以实现一种以人为本,尊重地域文化与记忆的城市发展模式。     

On the robustness to corrosion in the life cycle assessment of an existing reinforced concrete bridge

Management of existing structures has traditionally been based on condition assessment, based on visual inspections, disregarding the susceptibility of different structural types to aging and deterioration. Robustness, as a measure of the effects of unpredictable damage to structural safety can be a complementary information to the results of inspection. Although robustness has mostly been used to evaluate the consequences of extreme events, a similar framework can be used to investigate the result of aging, allowing a better understanding of the potential effects of deterioration and allowing a better allocation of available maintenance funding. In this work, a probabilistic structural robustness indicator is used to quantify the susceptibility of structures to corrosion. The methodology is exemplified through a case study comprising an existing reinforced concrete bridge deck, heavily damaged due to reinforcement corrosion, and finally demolished due to safety concerns. Robustness measures the bridge deck safety tolerance to reinforcement corrosion. The principal effects of corrosion, including loss of area and bond between concrete and steel are modelled using a non-linear finite-element model, coupled with a Response Surface Method to compute the bridge reliability as a function of the corrosion level, and finally used to assess robustness. Results show that the redundancy of the bridge allows significant redistribution of loads between elements with different corrosion levels. As a result, the bridge presents significant robustness and tolerance to reinforcement corrosion.     

Temporal variations of radon concentration in the saturated soil of Alpine grassland: The role of groundwater flow

Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Frêtes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times.     

Buckling of elastically restrained steel columns under longitudinal non-uniform temperature distribution

Columns under natural fire conditions are usually exposed to a non-uniform temperature distribution in the longitudinal direction. The motivation for this study stems from zone modeling of a compartment fire where the gas layers are artificially divided into two zones, namely the hotter upper zone and the cooler lower zone. However, for field modeling of a compartment fire, more detailed information of the temperature distribution can be obtained. Depending on the required accuracy, two different idealizations of temperature distributions are analyzed in this paper, namely linear distribution from zone modeling and piece-wise step distribution from field modeling in the longitudinal direction. Compared to a column with uniform temperature distribution, both of them represent more realistically the thermal response of a column, which experiences greater temperature with increasing height. The difference in temperature between the top and bottom ends of a column can be quite significant, particularly prior to the flashover condition. Advantage can be made of this in a performance-based approach to ascertain the stability of a column subjected to a prescribed fire size. In this paper, the stability of a pin-ended steel column under a non-uniform temperature distribution is studied. Although the formulations are based on linear elastic assumptions, the paper explores the validity aspect of the approach and shows that it can be applied to columns with a minimum slenderness ratio where plasticity is negligible. Across a section, the temperature is assumed to be uniform. Two linear elastic springs connected to the column ends simulate the axial restraints from the adjoining unheated structure. The objective is to derive closed-form solutions to enable engineers to quickly ascertain the column stability under a non-uniform temperature distribution, without recourse to finite element modeling.     

横向流动土体作用下的群桩反应性状

借助FLAC3D程序,分析了基坑开挖后土体横向流动作用下坑内群桩的反应性状。研究了两桩、四桩、五桩、六桩群桩中基桩的反应性状,并与相同位置的单桩反应进行了比较,得到了受横向流动土体作用的群桩相互作用规律:桩基连线平行于边坡布置的两桩,相互影响并不明显;而在其它情况下,前排桩对后排桩遮拦、后排桩对前排桩阻挡,均使受影响的桩基内力分布改变,桩身最大变形量减小;受周围越多、越近桩基的影响,基桩的内力和变位减少得越多。根据桩间土体的成拱特征,定性解释了群桩相互作用的机理与规律,具体工程的现场量测结果也验证了此结论。     

Degrees of destitution: a typology of homelessness in developing countries

There is an ongoing attempt to develop a globally acceptable definition of homelessness. Whether such a definition is broad and inclusive of squatters, and those living in particularly poor quality housing, or narrowly focused on street homelessness, it is likely to include a large population. Therefore, we are left with a need to develop criteria for identifying, allocating and prioritising appropriate support. Drawing on a study of homelessness in nine developing countries, this paper presents a new categorisation or typology of homelessness, based on choice and opportunity. It highlights the way in which homeless people, living in identical shelter situations, and for ostensibly similar reasons, might require different responses to support them out of homelessness. This paper does not seek to debate the definition of homelessness but to stimulate discussion on finding a way to identify and prioritise the needs of those included within any given definition.     

A procedure for assessing the functional reliability of hospital systems

An effective reliability-based procedure is presented to assess the capability of hospitals to be functional after a seismic event of a given intensity. Every major function in a hospital depends on the joint action of various cooperating services, which in turn are made up from a certain number of sub-services. Such a complex organization is described in terms of a logical scheme and subsequently reduced to a minimal cut-set representation. For each sub-service a collapse criterion is defined, by which the strength is compared to the action load, both represented as random variables. Strengths are evaluated through assessment analyses based on design drawings. Loads are evaluated from 3-D linear dynamic analyses under seismic input. This is given by the Eurocode 8 elastic response spectrum, scaled at a given peak ground acceleration and account for the position of the sub-service within the building. By calculating the failure probability of each service by FORM (First Order Reliability Method) or SORM (Second Order Reliability Methods), the probability of functional interruption is obtained in terms of Didevsen bounds, conditional on a given earthquake intensity. The method helps to single out weak elements and potential sources of damage (structural, non-structural, equipment) within the hospital. This allows: (a) to investigate quantitatively the effectiveness of different upgrading criteria, (b) to select rationally intervention hypotheses, both in the retrofitting and rehabilitation of existing hospitals and in the design optimization of new ones, and (c) to evaluate different investment options for seismic vulnerability mitigation. As an example, an application to a case study hospital is presented.