Structural health monitoring of innovative bridge decks

For more than a century, important civil engineering structures such as bridges, high-rise buildings, dams and marine platforms have contained iron or steel as the reinforcement for concrete or wood. The useful lives of such structures have often been severely limited by the corrosion of this ferrous component. Much thought has been given in recent years to constructing structures that are lighter, stronger and non-corrosive. These innovative structures are new and for these to be accepted by the engineering community monitoring is mandatory. ISIS Canada has been developing such structures and monitoring them. In this paper, innovative bridge decks that have been implemented are described.     

A review of methods for leakage management in pipe networks

Leakage in water distribution systems is an important issue which is affecting water companies and their customers worldwide. It is therefore no surprise that it has attracted a lot of attention by both practitioners and researchers over the past years. Most of the leakage management related methods developed so far can be broadly classified as follows: (1) leakage assessment methods which are focusing on quantifying the amount of water lost; (2) leakage detection methods which are primarily concerned with the detection of leakage hotspots and (3) leakage control models which are focused on the effective control of current and future leakage levels. This paper provides a comprehensive review of the above methods with the objective to identify the current state-of-the-art in the field and to then make recommendations for future work. The review ends with the main conclusion that despite all the advancements made in the past, there is still a lot of scope and need for further work, especially in area of real-time models for pipe networks which should enable fusion of leakage detection, assessment and control methods.     

Monte Carlo simulation of extreme traffic loading on short and medium span bridges

The accurate estimation of site-specific lifetime extreme traffic load effects is an important element in the cost-effective assessment of bridges. A common approach is to use statistical distributions derived from weigh-in-motion measurements as the basis for Monte Carlo simulation of traffic loading. However, results are highly sensitive to the assumptions made, not just with regard to vehicle weights but also to axle configurations and gaps between vehicles. This paper presents a comprehensive model for Monte Carlo simulation of bridge loading for free-flowing traffic and shows how the model matches results from measurements on five European highways. The model has been optimised to allow the simulation of many years of traffic and this greatly reduces the variance in calculating estimates for lifetime loading from the model. The approach described here does not remove the uncertainty inherent in estimating lifetime maximum loading from data collected over relatively short time periods.     

Reliability assessment of cable-stayed bridges based on structural health monitoring techniques

This paper presents the reliability analysis approach of long-span cable-stayed bridges based on structural health monitoring (SHM) technology. First, the framework of structural reliability analysis is recognised based on SHM. The modelling approach of vehicle loads and environmental actions and the extreme value of responses based on SHM are proposed, and then models of vehicle and environmental actions and the extreme value of inner force are statistically obtained using the monitored data of a cable-stayed bridge. For the components without FBG strain sensors, the effects and models (extreme values) of dead load, unit temperature load, and wind load of the bridge can be calculated by the updated finite element model and monitored load models. The bearing capacity of a deteriorated structure can be obtained by the updated finite element model or durability analysis. The reliability index of the bridge's critical components (stiffening girder in this study) can be estimated by using a reliability analysis method, e.g. first order reliability method (FORM) based on the models of extreme value of response and ultimate capacity of the structure. Finally, the proposed approach is validated by a practical long-span cable-stayed bridge with the SHM system. In the example, reliability indices of the bridge's stiffening girder at the stage after repair and replacement after 18 years of operation, and the damaged stage are evaluated.     

海外工程建设项目管理工程实践——商务/合同管理篇

针对海外项目商务合同管理,结合国际通用商务合同管理软件Oracle Primavera Contract Management的应用,简要介绍我们的工程实践。抛砖引玉,共同提高我国工程建设行业开拓国际市场的项目管理水平。     

城市小区防涝技术应用

城市内涝是城市建设中必须解决的难题,加强城市小区防涝技术的应用对我国频发的城市内涝灾害的缓解有重要作用。论文在探究我国城市排水现状的前提下,简单介绍了城市小区的水循环技术和一些防止水侵的生态技术。     

超长钻孔灌注桩后压浆技术在天津软黏土地基中的应用

后压浆技术是指成桩时在桩底或桩侧预埋压浆管和压浆装置,待钻孔灌注桩身达到一定强度后,通过压浆管路,利用高压压浆泵,将固化液注入桩端和桩侧。浆液经过渗透、填充、置换、劈裂、压密及固结等物理或化学作用的单独或共同作用,使桩端阻力和桩侧阻力得到不同程度的提高,从而改善桩基承载性能,减少沉降。     

大港体育馆大跨度空间桁架施工技术

随着空间结构施工技术的发展,大跨度空间桁架的应用越来越广泛。大港体育馆结构为大跨度空间管桁架结构,根据工程的重点及特点制定相应的施工方案,掌握关键的技术要求,保证工程的施工进度。其中吊装方案、起重机械和支撑胎架的选择,对工程的进度、质量和费用影响重大,必须经过分析比较后选择最佳方案。同时,将大港体育馆96m跨桁架分成3个整体吊装段及2个弧形管柱段,弧形管柱直接利用汽车吊固定在支架上,其余吊装段依次吊装在临时支撑上,顺利完成整个桁架的吊装过程。     

岩溶地质场地上某工程的桩基选型和施工

某工程位于岩溶较为发育的场地,地质情况较为复杂。根据场地具体岩土地质情况,并结合工程本身特点,分别确定采用筏板基础和桩基础。对于桩基础,通过各种工艺对比,选择冲孔灌注桩施工工艺,在施工过程中加强管理,采取多种质量保证措施,最终取得了良好的效果,为同类工程提供了经验。     

Potential for wastewater reuse in irrigation: case study from Aden (Yemen)

Wastewater treatment with waste stabilization ponds (WSP) is a very efficient, low cost and low maintenance operation. The treated wastewater from WSP should be considered as a valuable resource for reuse by water resources managers. Yemen’s water resources are currently experiencing a crisis, because all surface water and groundwater resources are exploited beyond the level of recharge. Promoting water reuse of treated wastewater for irrigation could mitigate this water crisis. This paper assesses the performance of a WSP in the city of Aden by examining the quality of treated sewage predominantly of domestic origin. A comparison with international guidelines reveals that it is possible to use the final effluent to a limited extent in irrigation. This paper includes an outline of the social, religious and political reasons for the water crisis, and explores the idea of reuse of effluent for different irrigation practices.