scholarly journals Service Life of Concrete Pedestal without Air Entrainment

2021 ◽  
Vol 64 (1) ◽  
pp. 93-107
Author(s):  
Niko Lindman ◽  
Jukka Kallio ◽  
Jukka Lahdensivu

Abstract Service life of nine wind power unit pedestals, which concrete grades between C45 and C55, were studied with four different service life models. The exact service life could be calculated only with two of them with the initial data. The service life models that were used in calculations: • Factor method • Deterioration and service life prediction of concrete subjected to freeze-thaw cycles in Na2SO4 Solution-method Service life models that were considered only at theoretical level: • FIB Bulletin 34 – Model Code for Service Life Design, and • An equation for determining freeze-thaw fatigue damage in concrete and a model for predicting the service life. The latter two methods are more theoretical, and they require laboratory tests to obtain more information before the calculations can be properly executed. This article concludes that damage to concrete due to freeze-thaw cracking is still poorly known and a sufficiently accurate service life model has not yet been developed for its computational modeling. Therefore, there is a need to develop a service life model suitable for Finnish climate and concrete grades, which could be used for estimating the damage rate of an existing concrete structure.

Author(s):  
Peter Schiessl ◽  
Phil Bamforth ◽  
Véronique Baroghel-Bouny ◽  
Gene Corley ◽  
Michael Faber ◽  
...  

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 721
Author(s):  
Jonas Niklewski ◽  
Philip Bester van Niekerk ◽  
Christian Brischke ◽  
Eva Frühwald Hansson

Performance-based, service-life design of wood has been the focus of much research in recent decades. Previous works have been synthesized in various factorized design frameworks presented in the form of technical reports. Factorization does not consider the non-linear dependency between decay-influencing effects, such as between detail design and climate variables. The CLICKdesign project is a joint European effort targeting digital, performance-based specification for service-life design (SLD) of wood. This study evaluates the feasibility of using a semi-empirical moisture model (SMM) as a basis for a digital SLD framework. The performance of the SMM is assessed by comparison against a finite element model (FEM). In addition, two different wood decay models (a logistic, LM, and simplified logistic model (SLM)) are compared. While discrepancies between the SMM and FEM were detected particularly at high wood moisture content, the overall performance of the SMM was deemed sufficient for the application. The main source of uncertainty instead stems from the choice of wood decay model. Based on the results, a new method based on pre-calculated time series, empirical equations, and interpolation is proposed for predicting the service life of wood. The method is fast and simple yet able to deal with non-linear effects between weather variables and the design of details. As such, it can easily be implemented as part of a digital design guideline to provide decision support for architects and engineers, with less uncertainty than existing factorized guidelines.


2010 ◽  
Vol 43 (10) ◽  
pp. 1397-1412 ◽  
Author(s):  
Irina Stipanovic Oslakovic ◽  
Dubravka Bjegovic ◽  
Dunja Mikulic

Author(s):  
Preston D. Vineyard ◽  
Brad J. Pease ◽  
Don Bergman ◽  
Armin Schemmann ◽  
Jacob E. Andersen ◽  
...  

<p>The Governor Mario M. Cuomo Bridge has replaced the existing Tappan Zee Bridge in New York. The new bridge was built by Tappan Zee Constructors, LLC. and is owned and operated by the New York State Thruway Authority (NYSTA). The new bridge is a 3.1 mile long crossing of the Hudson River and has an iconic main span structure, consisting of twin cable-stayed bridges, with 1,200’ main spans and 515’ side spans. Each new bridge carries four traffic lanes and the new crossing has been designed to accommodate the future addition of a rail bridge between the roadway decks. Utilizing a probabilistic-based service life design approach, the new bridge has been designed for a minimum 100-year service life before major maintenance for non- replaceable components, such as the foundations, sub-and superstructures. This paper provides the design features of the main span bridge and describes the design solutions, such as the use of fib Bulletin No. 34 to address the Service Life Design of the concrete components to address the durability challenges of this world- class project.</p>


2011 ◽  
Vol 368-373 ◽  
pp. 357-360
Author(s):  
Lei Jiang ◽  
Di Tao Niu ◽  
Min Bai

Based on the fast freeze-thaw test in 3.5% NaCl solution, the frost resistance of steel fiber reinforced concrete (SFRC) was studied in this paper. On the basis of scanning electron microscope (SEM) and mercury intrusion method, the microstructure and pore structure of SFRC was analysed. The reinforced mechanism of SFRC under the cooperation of freeze-thaw and NaCl solution was discussed. The test results show that adding appropriate amount of steel fibers into concrete can reduce the pore porosity and improve the compactness of concrete. The effects of steel fiber with proper volume fraction can inhibit the peeling of the concrete and reduce its damage rate. The volume of steel fiber on the frost-resisting property of SFRC is obvious.


Author(s):  
Maxime Verbist ◽  
Lina Nunes ◽  
Dennis Jones ◽  
Jorge M. Branco

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