Time filter

Source Type

Daniel R.A.,Ministry of Infrastructure and Environment
Global Thinking in Structural Engineering: Recent Achievements | Year: 2012

The areas and infrastructures crossed by bridges or viaducts can develop. As a result, existing space under the bridge may need to be widened or heightened. This paper presents some modification and reconstruction projects in the Netherlands, which have resulted in widening and heightening of the navigation clearance under existing bridges. Inland navigation, both cargo vessels and recreational, generates important requirements for the Dutch bridge crossings. Source

Daniel R.A.,Ministry of Infrastructure and Environment
Long Span Bridges and Roofs - Development, Design and Implementation | Year: 2013

Two structural systems dominate the choice of a very long span bridge nowadays - the suspension and cable-stayed bridge, both with one or more main spans and in steel or concrete version. Yet, the combination of these possibilities leaves the designer with quite many options. The question which option represents the best choice has been studied in details as part of the Western Scheldt Crossing project in the Netherlands. This paper presents the conclusions of that study and the comparative conceptual designs of four final bridge options. The results can be indicative for prospective studies on long span bridge crossings in other projects. Source

Lijzen J.P.A.,National Institute of Public Health and Environment RIVM | Otte P.,National Institute of Public Health and Environment RIVM | van Dreumel M.,Ministry of Infrastructure and Environment
Science of the Total Environment | Year: 2014

This article presents and discusses the main elements for a fundamental policy change for groundwater management in The Netherlands. The study analyzes the status and current use of groundwater, the increasing pressure in The Netherlands and many other countries on the natural soil-water system, the effects on quality and quantity of groundwater and the use of the subsoil. An overview is given of the current national and European regulations regarding groundwater and related policies for e.g. drinking water, soil policies and other interventions in the subsurface. The Dutch National Government is developing a new framework for groundwater management that aims a sustainable use of groundwater not only in environmental, but also in economic and social perspective. This framework for groundwater will benefit the Structure vision on the subsoil. The question is how 'sustainable use' can be a guiding principle in groundwater management, strengthening the relation between groundwater quantity and quality. It is proposed to define a generic National approach for the assessment of new and existing activities with potential effects on groundwater and for groundwater quality assessment. Additionally it is proposed to give local authorities the opportunity to set area-specific objectives on a regional or local scale to adjust for specific societal needs and area-specific characteristics. For setting these objectives it is recommended to use the concept of ecosystem services as a leading principle for defining the groundwater quality and quantity (e.g. for use as source for drinking water, aquifer thermal storage and sustaining terrestrial and aquatic ecosystems). © 2014 Elsevier B.V. Source

Mohd Hasan M.R.,Universiti Sains Malaysia | Hamzah M.O.,Universiti Sains Malaysia | Van De Ven M.,Technical University of Delft | Voskuilen J.,Ministry of Infrastructure and Environment
Construction and Building Materials | Year: 2016

Mortar creep takes place when the asphalt mortar continuously migrates downwards due to gravitational forces and can significantly disrupt air voids continuity in porous asphalt samples. This study was an extension to a previous work that ascertained the existence of the binder creep phenomenon as reflected from the continual permeability loss especially on samples conditioned at elevated temperatures. Nonetheless, in this paper, the terminology "mortar creep" was adopted instead of "binder creep". This is because, in an asphalt mixture, the aggregates are glued together not by the binder in isolation, but by the mortar; which is comprised of asphalt binder, fine aggregates and filler. The variables investigated included aggregate gradation, binder type, bitumen content and conditioning temperature. The mixes were prepared using conventional bitumen (60/70 pen. grade) and modified asphalt binder (PG76) at three levels of binder content at 0.5% increment. Permeability loss was continuously monitored over an extended period up to 120 days using a simple falling head water permeameter. Over the test period, the samples were separately conditioned at 15 °C, 20°C, 30°C and 35°C. The results showed that all factors significantly affect the occurrence of mortar creep in porous asphalt prepared in the laboratory, especially for the specimens conditioned at the highest temperature. Permeability loss was more significant on specimens' prepared using conventional binder at a higher bitumen content. © 2016 Elsevier Ltd. All rights reserved. Source

Daniel R.A.,Ministry of Infrastructure and Environment
Assessment, Upgrading and Refurbishment of Infrastructures | Year: 2013

We know that the condition of bridges and viaducts must answer the requirements of developing traffic loads. However, also the infrastructure below the bridge develops and generates requirements for that bridge. As a result, the existing clearance below the bridge may need to be heightened or widened. This paper presents three bridge adaptation and reconstruction projects in the Netherlands, which have resulted in heightening and widening of the navigation clearance below existing bridges. Inland navigation - carrying cargo, passengers or just recreational - constitutes an important branch of the Dutch economy. Additionally, the discussed projects comprised substantial improvements of technical condition, which extended the service life of the structures. Source

Discover hidden collaborations