Broadcasting from the “Mediated Center:” Baltimore’s Candelabra Television Tower,circa 1959

ABSTRACT

The rise of post-WWII television markets around the world required new technical solutions for broadcast media. These solutions became novel examples of urban-scale infrastructure, including the “television tower” as a unique structure. Among early American examples is Baltimore’s three-mast “candelabra” television tower, completed in 1959. Although the project’s feasibility depended upon advances in structural design, its most significant innovation was institutional. As an early example of “infrastructure sharing,” Baltimore’s candelabra tower illustrates how innovative built form can engender a new relationship among technology, urban infrastructure, and the production of cultural capital.     

A 3D Model for Optimizing Infrastructure Costs in Road Design

In this article, the optimal design of a road joining two terminals is investigated. A geometric model is proposed including horizontal transition curves and vertical curves, obtaining parameterizations for the central axis of the road as well as for its entire surface. These parameterizations allow to express and compute, with great simplicity, the major infrastructure costs, including land acquisition, clearance, pavement, maintenance, and earthwork, where multiple layers of materials with different costs can be handled. The road design problem is formulated as a smooth constrained optimization problem and a two‐stage algorithm is suggested for its numerical resolution. Finally, numerical results are presented in an academic test and in a case study that propose designing a bypass in a Spanish national road (N‐640) to avoid crossing Monterroso's town center.     

Contested urban streets: Place,traffic and governance conflicts of potential activity corridors

Activity Corridors have emerged as one redevelopment form for accommodating growth within dispersed, car-centric cities. This has seen a new interest in the form and function of urban arterial roads. Efforts to increase development intensity in established suburbia, however, are often highly contentious among local stakeholders. It is unclear whether the offer of improved public transportation infrastructure - a central component of the Activity Corridor concept - influences residents' support for taller or denser built form. This dynamic was explored using a case study along an urban arterial road in Perth, Western Australia. A household survey identified residents' attitudes to increasing development intensity in exchange for varying public transport provision scenarios. The results informed interpretive interviews with planning practitioners. Residents were more supportive of increasing development intensity if public transport was improved. Planners questioned whether recent land use and transport planning approaches adequately reflected community expectations for local “amenity”, and noted several key governance constraints to developing urban Activity Corridors.     

Multiagent Simulation for Complex Adaptive Modeling of Road Infrastructure Resilience to Sea‐Level Rise

Infrastructure systems in coastal areas are exposed to episodic flooding exacerbated by sea‐level rise stressors. To enable assessing the long‐term resilience of infrastructure to such chronic impacts of sea‐level rise, the present study created a novel complex system modeling framework that integrates: (i) stochastic simulation of sea‐level rise stressors, based on the data obtained from downscaled climate studies pertaining to future projections of sea level and precipitation; (ii) dynamic modeling of infrastructure conditions by considering regular decay of infrastructure, as well as structural damages caused by flooding; and (iii) a decision‐theoretic modeling of infrastructure management and adaptation processes based on bounded rationality and regret theories. Using the proposed framework and data collected from a road network in Miami, a multiagent computational simulation model was created to assess the long‐term cost and performance of the road network under various sea‐level rise scenarios, adaptation approaches, and network degradation effects. The results showed the capabilities of the proposed computational model for robust planning and scenario analysis to enhance the resilience of infrastructure systems to sea‐level rise impacts.     

Scalable Structural Modal Identification Using Dynamic Sensor Network Data with STRIDEX

This article uses the formulation of the structural identification using expectation maximization (STRIDE) algorithm for compatibility with the truncated physical model (TPM) to enable scalable, output‐only modal identification using dynamic sensor network (DSN) data. The DSN data class is an adaptable and efficient technique for storing measurements from a very large number of sensing nodes, which is the case in mobile sensor networks and BIGDATA problems. In this article, the STRIDEX output‐only identification algorithm is proposed for the stochastic TPM to estimate structural modal properties (frequencies, damping ratios, and mode shapes) directly from DSN data. The spatial information produced by this novel algorithm, called STRIDEX (“X” for extended), is scalable, as demonstrated in a strategy to construct high‐resolution mode shapes from a single DSN data set using a series of independent identification runs. The ability to extract detailed structural system information from DSN data in a computationally scalable framework is a step toward mobile infrastructure informatics in a large urban setting. The performance of the STRIDEX algorithm is demonstrated, using the simulated response of a 5,000 DOF structure, and experimentally, using measurements from two mobile sensor cars, which scanned about 8,000 points on a beam specimen in the laboratory. In the experimental results, a mobile sensor is shown to provide over 120 times more mode shape points than a fixed sensor.     

Assessment of the neighborhood environmental effects of highway improvements through micronetwork simulation

New Cut Road is a major arterial highway serving South Louisville. Until recently, it was a narrow two‐lane highway of rural‐type design carrying up to 14,000 vehicles per day under forced flow conditions. Then construction began to widen the road from Southside Drive to Old Third Street Road, as a result of Urban Corridor Demonstration Program funding. The impacts (traffic, noise, and air pollution) on the neighborhoods surrounding this widening have been measured through micronetwork simulation techniques. Traffic will be diverted from surrounding roads (up to 20 percent) to the widened New Cut facility, thereby eliminating “over‐capacity” conditions in these facilities, adding several years’ life. Further, expeditious movement of vehicles through the New Cut Road “area of influence” will have a beneficial, albeit small, effect on the local air and noise environment. New Cut Road will be a highly cost‐effective, low‐capital‐intensive improvement.     

探索现场施工管理在公路工程中的运用

“要致富,先修路”。对于每个城市建设发展来说,道路的联通才能更好地发展经济。如何依据公路施工的特点对公路施工现场进行有效地管理,并将施工中遇到的常见问题加以规避,成为了公路建设者需要思考的问题。     

论述路桥设计中的安全性和耐久性

经济的发展离不开道路桥梁等基础设施的建设,道路桥梁工程也逐渐成为影响我国经济发展的基础。我国的道路桥梁在近几年得到了迅速发展,但由于设计或施工的原因,路桥工程在安全性与耐久性等方面还存在着隐患。     

Transport infrastructure and regional convergence: A spatial panel data approach

This article examines the contribution of transport infrastructure to the regional convergence in Spain for the period 1980–2008. Spatial econometric techniques are employed to decompose the direct, indirect and total effects of roads, railways, ports and airports. In addition, the analysis is complemented by estimating the determinants of the regional allocation of transport investments. Evidence confirms the presence of absolute and conditional convergence. However, only roads appear to have an impact on this convergence process. It is also understood that the main driver of transport investments has been the equalization of the infrastructure endowment between the different Spanish regions. The reduction of inequalities between regions in terms of road provision could explain the positive contribution of roads to the process of regional convergence in Spain.     

Private toll roads: Competition under various ownership regimes

Interest is growing in private toll roads as an alternative to public free-access road infrastructure. Private toll roads have gained favour for various reasons, including a dearth of public funds for road construction and maintenance, increasing traffic congestion, and growing acceptance of the user-pay principle in general, and road pricing in particular. This paper focuses on allocative efficiency of private toll roads. The model features one origin and one destination linked by two parallel routes that can differ in capacity and free-flow travel time. Congestion takes the form of queueing. Prospective travellers decide whether to drive, and if so on which route and at what time. Three private ownership regimes are considered: (1) a private road on one route and free access on the other, (2) a private roads duopoly, and (3) a mixed duopoly with a private road competing with a public toll road. Private toll roads are generally found to enhance allocative efficiency (measured by social surplus) relative to free access. The efficiency gain is greater when both routes are tolled, tolls are varied over time to eliminate queueing, and when no private road has a dominant fraction of total capacity. Paradoxically, mixed duopoly can be less efficient than a private duopoly. Price leadership by a public toll road avoids this possibility, although leadership typically yields little additional efficiency gain. Received: June 1998/Accepted: October 1998     

“Lebendige” Fußgängerbrücken – eine Herausforderung

“Lively” Footbridges – a real challenge. This contribution gives an overview on the “state‐of‐the‐art” of the control of vibration problems of footbridges. If modern footbridges are designed for static loads only they may be very susceptible to vertical as well as horizontal vibrations. Hence a dynamic design is mostly necessary. Thereby a true understanding of possible dynamic phenomena and the mathematical formulation of the dynamic actions are essential. Based on the actions of one person from walking, running or jumping, respectively, the actions of several or many persons have to be considered including the “lock‐in” effect which can lead to the synchronisation of a substantial percentage of the persons. Measures have to be taken, such as frequency tuning of the structure, calculation of a forced vibration and limitation of amplitudes, special measures etc. In many cases the installation of one or several tuned vibration absorbers is an effective and elegant alternative.     

Improvement of rural access roads in developing countries with initiative for self-reliance of communities

This study presents an approach to help alleviate poverty from a geotechnical engineering viewpoint. In order to improve accessibility of rural access roads to communities in rural areas of developing countries, a method to reinforce the base course with “do-nou”, a Japanese term for soil bag, has been developed. With this method, local available resources can be mobilized and the community can be involved. The main challenges are to build the base course without the necessity for qualified base course material or compaction equipment to bear the traffic load. The applicability of the available bags in developing countries to the base course was confirmed through tensile strength tests. The effectiveness of the reinforcement of “do-nou” was evaluated through a series of full-size model driving tests. The base course, built with “do-nou” and compacted manually, was able to reduce the settlement of the surface to 33% of that built with the conventional method, just by the spreading of gravel subjected to the traffic load. The technical transfer of reinforcement with “do-nou” to communities in developing countries will make it possible for the members of the communities themselves to work on rural access roads to improve trafficability. The applicability and limitations of road repair with “do-nou” were confirmed through a review of demonstrations and practices in Kenya. Typical sections with flat terrain, sags and gentle slopes, where trafficability was lost during the rainy seasons, were found to be effectively repairable with “do-nou”. Sections with steep slopes, however, are beyond the scope of “do-nou”. From an assessment of the impact after the technical transfer in Kenya, it was found that the application of “do-nou” motivates and empowers the community to initiate its own development. This earth reinforcement technology can be applied to the skills utilized by the communities in developing countries to improve the trafficability of rural access roads by considering the conditions of rural areas. Based on this technology, an approach is proposed to promote the concept of community involvement in repairing rural access roads and to enable the members of communities to improve the conditions of the roads by themselves at a low cost.     

Cultural Heritage of Roads and Road Landscapes: Classification and Insights on Valuation

Over time roads and their surroundings gained historic and cultural significance. This significance is oftentimes acknowledged and numerous roads and road infrastructure objects with their surrounding environment are listed and protected. Notwithstanding this, it is necessary to note that the ways in which roads, their surrounding environment, and adjacent objects can manifest heritage values, can be complex, and are not limited to historic roads or historic road landscapes. Different categories of these ways can be distinguished: road landscape can be recognized as cultural heritage, cultural heritage objects functionally related or unrelated to the road can exist in its surrounding environment, and roads can also be treated as cultural heritage objects in landscape. Understanding the dimensions of the cultural heritage of roads and road landscapes and analysing its values can be important not only to the environmental, technological, and cultural history, but also to the future-oriented heritage management and territorial planning fields. The article is aimed to present a framework for analysing the cultural heritage of the automobile roads and road landscapes consisting of the system for its classification and of identification of factors determining its cultural value and the categories of economic value it can provide. Assessment possibilities of these values are also shortly discussed.     

Preliminary analysis of the dynamic interaction between Norra Länken and a subway tunnel for Stockholm, Sweden

A large infrastructure project called “Ring road Around Stockholm” is presently being planned. A large proportion of the roads will be constructed underground. All kinds of hazardous materials; even explosive gases and liquids, will be allowed to be transported. At Roslagstull, which is located at the northern boundary of the city, five underground road tunnels will cross over an existing subway tunnel, with only about 3 m of rock between them. A scenario in which a truck loaded with explosive gas or liquid starts to leak and then explodes has been proposed by Stockholm's Street and Traffic Administration. Consequently, the effect on rock and the reinforcement surrounding the subway tunnel must be evaluated. This paper presents the results of a study based on two-dimensional distinct element modelling of the rock mass and reinforcement response to a load caused by an exploding truck as described above. Two different assumptions regarding the explosion load have been simulated—namely, static load and fully dynamic load. The study (i) provides general information about the rock mass and reinforcement response for a specific assumption regarding the rock mass conditions, and (ii) compares the results from the two different assumptions regarding the representation of the explosion load. Both unreinforced and reinforced conditions have been modelled for each loading condition (i.e., a total of four models). The results indicate that for the unreinforced models, the differences in the model response are not dramatic when compared to the models with static and dynamic representation of the explosion load. On the other hand, the reinforced models indicate major differences, particularly in the reinforcement response. All numerical analyses presented in this paper were performed using the two-dimensional distinct element code UDEC (Itasca 1992).     

“双全法”在高校基建投资控制中的应用与研究

随着高校建设规模扩大,基建投资成为高校管理工作的重点.从基建管理者角度,探讨如何用“全员教育”和“全环节控制”的“双全法”控制工程造价.从设计方案的确定、施工队伍的选择、材料的采购供应、施工过程的控制、预结算的审核等方面说明“双全”法在基建投资管理中的具体运用和重要意义,阐述以设计阶段为重点,技术与经济相结合的工程造价全过程动态控制方法.结合高校基建的特点,强调“阳光招标”的重要性.     

A Study to Evaluate the Seismic Response of Road Embankments

A crucial matter related to roads in seismic areas is to ensure viability during the post-seismic stages, especially if the road represents an important or unique way to reach towns that may be potentially hit by strong earthquakes. Verification of road viability under seismic actions requires not only safety assessment of the failure mechanisms which may jeopardize single road components (embankment, viaduct, bridge, etc.) but also evaluation of performance. Viability of a road may be compromised by an unsatisfactory response of road embankments. The vehicle flux may be, in fact, inhibited or reduced if a road embankment suffers global instability mechanisms or significant permanent displacements mainly at the contact with structural elements (e.g., viaducts, bridges) that do not move significantly. In this case the embankment permanent displacements turn out into steps or separations. The paper accounts for the different stages followed to study the seismic performance of the road embankments located along a sample road branch of about 5 km. Preliminary activities consisted in characterizing the geological area of the sample road, in selecting the potentially vulnerable embankments and in carrying out in-situ investigations to properly characterize the physical and mechanical properties of the embankments and foundation soils. A seismological study of the sample area was performed in order to characterize the reference seismic actions needed for the numerical analyses. The seismic response of the embankments was evaluated by a pseudo-dynamic approach and an advanced dynamic model. In the latter, the equations describing dynamic equilibrium and compatibility were merged with an elastoplastic combined-hardening constitutive law that properly models soil response under cyclic loads. The embankment's seismic performance was predicted in terms of permanent settlements at the embankment top surface versus the peak acceleration of the reference input motions.     

Encoder–decoder network for pixel‐level road crack detection in black‐box images

Timely monitoring of pavement cracks is essential for successful maintenance of road infrastructure. Accurate information concerning crack location and severity enables proactive management of the infrastructure. Black‐box cameras, which are becoming increasingly widespread at an affordable price, can be used as efficient road‐image collectors over a wide area. However, the cracks in these images are difficult to detect, because the images containing them often include objects other than roads. Thus, we propose a pixel‐level detection method for identifying road cracks in black‐box images using a deep convolutional encoder–decoder network. The encoder consists of convolutional layers of the residual network for extracting crack features, and the decoder consists of deconvolutional layers for localizing the cracks in an input image. The proposed network was trained on 427 out of 527 images extracted from black‐box videos and tested on the remaining 100 images. Compared with VGG‐16, ResNet‐50, ResNet‐101, ResNet‐200 with transfer learning, and ResNet‐152 without transfer learning, ResNet‐152 with transfer learning exhibited the best performance, achieving recall, precision, and intersection of union of 71.98%, 77.68%, and 59.65%, respectively. The experimental results prove that the proposed method is optimal for detecting cracks in black‐box images at the pixel level.     

Inner Mongolia must “leapfrog” the energy mistakes of the western developed nations

The purpose of the Asian Development Bank Report was to investigate and study the energy infrastructure development of western industrialized nations along with their impact on the environment. Then there could be an analysis of how IMAR could “leapfrog” or jump over the mistakes of the west and create an energy infrastructure for itself and China. The report reflects and summarizes this historical energy infrastructure development over the 20th Century. The five countries were the UK, Germany, S. Africa, USA and Australia.The foreign energy advisors felt that there were two additional elements that needed to be included. First was the fact that the USA as a whole was different than its regions or states, particularly California. So the nation-state of California was added. Secondly, the western nations of Germany and S. Africa in particular, had carefully considered some advanced coal technologies that were “cleaner” than the traditional and conventional approaches to mining. Both nations developed these “clean coal” technologies that are now being used more and more today in other developed nations like the USA. If IMAR was to retain much of its coal production and reduce it over time, then it had to install these technologies now to reduce global warming and reverse the climate change caused by current coal mining.