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De Boer A.,Center for Infrastructure | Van Der Veen C.,Technical University of Delft
3rd International fib Congress and Exhibition, Incorporating the PCI Annual Convention and Bridge Conference: Think Globally, Build Locally, Proceedings | Year: 2010

With the demand of a reliable infrastructure and the related question to the condition of the 'old' structures in infrastructure, a new fast method is developed to get answers on this hot question. In the past the model is setup with a 1D line model, later on with 2D elements in a 2D or 3D global structure geometry. Today a solid model of a structure can be setup in a very easy way with the actual FE packages. Integration of the stresses over one or both directions in a 3D solid model give reinforcement moments or forces for even surface or line results, which can be compared with the results of a simple surface or line model from the past. Today it is possible to control the condition of the concrete structure by a socalled sequential static analysis in an acceptable elapse time of 10-20 minutes, instead of days. Now, the crack behaviour of the concrete is treated by a secant calculation process (reduced modulus of Elasticity) to avoid typical nonlinear problems. All other material aspects are treated in a nonlinear way. Safety aspects related to the reexamination of existing structures can be treated in a very fast way.


News Article | May 9, 2017
Site: marketersmedia.com

Texas – GSG Distribution, a Texas-based concrete distribution company that serves the Southwest Region of the United States, including Texas, Oklahoma, Louisiana, Arkansas, Alabama, and Mississippi, this week had a case study for one of their distributed products, SCP 327, released regarding the Texas A&M University Center for Infrastructure Renewal. To be one of the nation’s highest ranked, state of the art facilities dedicated to the research of concrete, the Center of Infrastructure Renewal will use the Spray-Lock Concrete Protection 327 to drastically reduce surface cracking in exposed polished concrete areas. “SCP will permanently prevent moisture related issues in areas to receive flooring in the center, as well as prevent any cracking in exposed areas,” said Brandon Thomas, Director of Sales at GSG Distribution. “The SCP is also being utilized on the rooftop concrete to provide a rapid cure, saving time in the entire construction process.” It has been found that SCP 327 will provide a better alternative to a 28-day water ponding, while also offering same-day, within one hour, access to the slab. This internal cure will therefore reduce shrinkage of the slab, which in most cases contributes to the surface cracking. “With SCP 327, any flooring or coating can be placed in only 14-days from the time of pour,” said Mr. Thomas. “It’s a curing medium, hardener, densifier, and concrete waterproofing product all in one. Additionally, SCP 327 also eliminates slab curl, efflorescence, surface cracking, spalling and freeze-thaw damage. We are excited to see the finished result for this new innovative center.” The world-class Center for Infrastructure Renewal will feature laboratories and testing facilities equipped with the latest technology to study Pavement Materials, Corrosion, Materials Evaluation, Electric Power Grid, Pipeline System Integrity, and Infrastructure Systems. For more information, or to read more about GSG Distribution’s products, visit: http://gsgdistribution.com/. For more information, please visit http://gsgdistribution.com


De Boer A.,Center for Infrastructure | Booij N.,Center for Infrastructure
Bridge Maintenance, Safety, Management, Resilience and Sustainability - Proceedings of the Sixth International Conference on Bridge Maintenance, Safety and Management | Year: 2012

Inspection techniques are not new in the world of the bridge management systems. Related to structural safety and risk oriented together is more and more wanted, while the budget for maintenance is growing. Till today it was quite common, that the inspection office contains two arts, the inspection part and an additional analysis part of the structure. The inspection part was foreseen and the calculation part needs an extra budget for the contractor. So a need was born to relate the inspection part to the calculation part based on risk analysis in order to minimize the extra costs after the inspection part. A weighted method related to the structural safety of the structure and the condition of the structure indicates a so-called risk index of the structure. The first possible difference between the design parameters of the structure and the actual use or the wished use of the structure gives a first parameter of the weigthed method. A second difference is the hardening behaviour of the concrete material in the structure. The concrete structures build before 1975 show a hardening behaviour, where sometimes the concrete has twice the strength of the old design circumstances. This means the structure can carry more load. The traffic load could be growing too, this item is an important negative parameter for the structure. Till now the scope is mentioned in a way that all parameters from the design period of the structure are known. However during all the years some information can be destroyed or lost, this indicates a higher risk for the safety of a structure because there are coming some uncertainties around the design parameters. All together a weigthed method is developed to get a ranking of the structures for extra calculations of the structure and the way of inspection of a structure. This method can be explained and discussed in a paper on a wide range of concrete structures build in the 20 th century. © 2012 Taylor & Francis Group.


van der Velde J.,Ministry of Infrastructure and the Environment | van der Velde J.,Center for Infrastructure | Klatter L.,Ministry of Infrastructure and the Environment | Klatter L.,Center for Infrastructure | And 2 more authors.
Structure and Infrastructure Engineering | Year: 2013

The objective of the national agency for road and water infrastructure in the Netherlands is to deliver best service to the public at lowest life cycle cost, given public acceptable risk. This requires a sound and well-structured system of management and maintenance. Such a system consists of elements such as reliable asset data, long-term performance based maintenance programmes, clear steering objectives and transparent procurement strategies. Asset management will make it possible to show what network performance can be achieved, at which costs and with which associated risks. A model defining an asset owner role, an asset manager role and a service provider role was chosen as a governing principle for the design of the asset management process. The design of the process described in the paper sets the boundary conditions to carry out projects with the minimum amount of hindrance for the user while involving the market in the best possible way. © 2013 Copyright Taylor and Francis Group, LLC.


Gulikers J.,Center for Infrastructure
European Journal of Environmental and Civil Engineering | Year: 2010

This paper addresses the theory for a statistical analysis of the results of potential mapping performed on reinforced concrete structures. The basic assumption for this analysis is that the distribution of potentials for both corroding and passive steel can be adequately described by a normal density distribution. This treatment is applied to a number of situations as to exemplify the calculation procedure. Eventually, this statistical analysis will result in improved potential criteria to distinguish corroding from passive steel reinforcement. Moreover, this procedure allows to assign to any value of the measured potential the corresponding probability to deal with an active corrosion process and provides a better estimate of the amount of corroding steel present in the structure. © 2010 Lavoisier, Paris.


Ramachandra T.V.,Indian Institute of Science | Ramachandra T.V.,Center for Infrastructure
Renewable and Sustainable Energy Reviews | Year: 2010

Rural population of India constitutes about 70% of the total population and traditional fuels account for 75% of the rural energy needs. Depletion of woodlands coupled with the persistent dependency on fuel wood has posed a serious problem for household energy provision in many parts. This study highlights that the traditional fuels still meet 85-95% of fuel needs in rural areas of Kolar district; people prefer fuel wood for cooking and agriculture residues for water heating and other purposes. However, rapid changes in land cover and land use in recent times have affected these traditional fuels availability necessitating inventorying, mapping and monitoring of bioresources for sustainable management of bioresources. Remote sensing data (Multispectal and Panchromatic), Geographic Information System (GIS), field surveys and non-destructive sampling were used to assess spatially the availability and demand of energy. Field surveys indicate that rural household depends on species such as Prosopis juliflora, Acacia nilotica, Acacia auriculiformis to meet fuel wood requirement for domestic activities. Hence, to take stock of fuel wood availability, mapping was done at species level (with 88% accuracy) considering villages as sampling units using fused multispectral and panchromatic data. © 2009 Elsevier Ltd. All rights reserved.


De Boer A.,Center for Infrastructure | Van Der Veen C.,Technical University of Delft
fib Symposium 2012: Concrete Structures for Sustainable Community - Proceedings | Year: 2012

Cantilever bridges, constructed in the Netherlands, are mostly designed for the main river crossings. A lot of them are constructed in the period of 1960-1975. Material time dependency modelling was rather time consuming and computer simulations of these phenomena were poor available yet. The longterm behaviour of these bridges was simulated in those days in the framework of the fib ModelCode1978. Later on the ModelCode1990 was extended till a load dependency of the phenomena creep. However a lot of computer programs did not include these load dependency related to creep. It was easier to add a so-called time dependant factor to the original creep formulation coming from the fib ModelCode78. Modifications to the fib ModelCode1990 (and properly also the fib ModelCode2010) will lead to better deformation predictions which will be shown in this paper.


Tromp L.,Royal HaskoningDHV | De Boer A.,Center for Infrastructure
Engineering for Progress, Nature and People | Year: 2014

Around the world the number, size and level of complexity of FRP structures in infrastructure increases rapidly, and it is seen that also for traffic bridges and lock doors FRP is selected in commercial projects. The main challenge in design guidance is the fact that FRP can be made by many different processes with varying degrees of automation. So how can we deal with this variety? How do we take the limited experience branch wide into account? The CUR 96 [1] is the Dutch Design Guidance for FRP in Infrastructure (2003). It is currently being revised into Eurocode format and chapters are added dealing with aspects such as quality control and design verification by tests. The partial factors of the CUR96 guidance were compared to material test data on samples that have been exposed to water for 10 years. Due to the limited number of samples this cannot be considered as a full calibration but allows for a valuable assessment of the validity of the factors.


Holguin-Veras J.,Center for Infrastructure | Holguin-Veras J.,Rensselaer Polytechnic Institute | Allen B.,KLD Associates Inc.
Transportation Research Part A: Policy and Practice | Year: 2013

Time of day pricing uses higher tolls in the peak-hours to induce passenger car traffic to consider a switch to more sustainable alternatives in terms of time of travel, mode, route, and payment method. In designing such programs, special attention must be paid to ensure that the drivers' behavioral responses to pricing are well understood. This is important because, if the analysts do not correctly predict users' reactions, policies and programs may fail to achieve their objectives. Knowledge of users' responses to pricing assists policy makers to design effective pricing programs.This paper investigates the behavioral impacts of time of day pricing using stated preference data collected from regular users of the New Jersey Turnpike. As part of the data collection process, the respondents were presented with hypothetical toll scenarios and asked how they would change behavior. Using these data, discrete choice models were estimated as a function of policy variables and respondents' socio-economic attributes. The final model shows that time of day pricing could induce changes in the payment method used to pay the tolls, route choice, and time of travel. It was found that the amount of the toll, total travel time, and schedule delay-together with other socio-economic variables-were important factors in determining which alternative a user would select. Market share analyses for basic toll scenarios were conducted to assess the overall impacts of alternative toll scenarios. Elasticities were computed for the key variables in the model. In its final sections, the paper discusses policy implications and chief conclusions. © 2013 Elsevier Ltd.


Gulikers J.,Center for Infrastructure
Applications of Statistics and Probability in Civil Engineering -Proceedings of the 11th International Conference on Applications of Statistics and Probability in Civil Engineering | Year: 2011

With respect to durability of existing reinforced concrete structures a practical approach has been developed to quantify the present condition level of individual structural components based on results obtained from in-situ measurements combined with information gained by visual inspection. In addition a detailed calculation procedure has been elaborated as to take into account degradation over time. For existing structures the focus is placed on reinforcement corrosion induced by chloride-ingress. The approach adopted is semi-probabilistic in nature by considering spatial and random variability of cover depth, critical chloride content, and measured chloride profiles. © 2011 Taylor & Francis Group, London.

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