Failures of Concrete Slit Drains, Caused by Inappropriate Dilation Material Inserted into Multi-Layer Road Systems

2014 ◽  
Vol 587-589 ◽  
pp. 1148-1151 ◽  
Author(s):  
Petr Tej ◽  
Jiří Kolísko
Keyword(s):  
Computer Simulation ◽  
Concrete Slabs ◽  
Layer System ◽  
Expansion Joints ◽  
Thermally Induced ◽  
Concrete Shrinkage ◽  
Highly Sensitive ◽  
Road Systems ◽  
Construction Practice ◽  
Road System

This paper introduces a real case from construction practice illustrating extensive damage to concrete slit drains, followed by the relevant computer simulation. From the computer simulation and lab tests it follows that the failures of concrete slit drains can be easily caused by deformations of the concrete slabs constituting the surrounding multi-layer road system. Thermally-induced expansions and contractions, as well as concrete shrinkage, produce, in non-dilating connection, stress in the link between the multi-layer road system and the lateral walls of the slit drains. The slit drains are highly sensitive even to a very small malfunction of the expansion joints (e.g. clogging of the slit by solid materials), or their bad installation. It is apparent that failures (cracks) in the slits arise even by the slight compression of a slit drain (to the order of tenths of a millimetre). The analysis presented shows the necessity for a careful installation of expansion joints during the placement of the slit drains into the surrounding multi-layer system, which could induce horizontal pressures on the drains. The study is concluded by recommendations for designers.

scholarly journals ОКРЕМІ ПИТАННЯ АНАЛІЗУ УШКОДЖЕНЬ БУДІВЕЛЬНИХ ОБ’ЄКТІВ ВЕЛИКОЇ ПЛОЩІ

2018 ◽  
pp. 356-364
Author(s):  
Марек Дохойда ◽  
Йоанна Вітковска-Добрев
Keyword(s):  
Soil Water ◽  
Expansion Joints ◽  
Concrete Shrinkage ◽  
Design And Implementation ◽  
Water Conditions ◽  
Complex Engineering ◽  
Soil Water Conditions ◽  
Bottom Slab

У роботі представлений перелік проблем, що супроводжують будівельні об'єкти великої площі, в тому числі й підземні гаражі. Здійснено технічний аналіз окремих проблем, що виникають в таких будівлях під час їх експлуатації. Проектування, а пізніше і будівництво підземних гаражів найчастіше, пов'язане з вирішеням складних інженерних питань. Згідно з ними до найпоширеніших конструкційних недоліків у підземних гаражах віднесні: тріщини нижньої плити, порушення поверхових перекриттів, невластиве кручення бетону, відсутність дилатації або також помилково прийняті ґрунтово-водні умови.The paper concerns complex engineering challenges associated with multi-storey underground car parks. An analysis of selected issues in underground garages during the exploitation was performed. The design and implementation of structures of which function are underground garages is most often associated with serious engineering challenges. For structural reasons frequently occurring faults in garages may include fracture of the bottom slab and intermediate floors resulting from improper design of reinforcement, concrete shrinkage, lack of expansion joints or incorrectly adopted soil-water conditions.

Characterization of Thermally Induced Stress in IC Packages Using PiFETs Over a Temperature Range of −180°C to 80°C

2014 ◽  
Vol 2014 (1) ◽  
pp. 000500-000504 ◽  
Author(s):  
Francy J. Akkara ◽  
Uday S. Goteti ◽  
Richard C. Jaeger ◽  
Michael C. Hamilton ◽  
Michael J. Palmer ◽  
...  
Keyword(s):  
Shear Stress ◽  
Stress Component ◽  
Shear Stress Component ◽  
Thermally Induced ◽  
Temperature Changes ◽  
Temperature Range ◽  
Induced Stress ◽  
Highly Sensitive ◽  
Stress Components

In certain applications, IC packages may be exposed to extreme temperatures and knowledge of thermally induced stress aids the prediction of performance degradation or failure of the IC. In the devices that are used in extreme conditions, the stress is caused mainly by the mismatch in expansion of various materials triggered by the different coefficients of thermal expansion. This work performed in this study is conducted using NMOS current mirror circuits that are cycled through a wide temperature range of −180°C to 80°C. These circuits are highly sensitive to stress and provide well-localized measurements of shear stress. The sensors are fabricated in such a way that the effects of certain stress components are isolated. These sensors are also temperature compensated so that only the effect of mechanical stress components is observed and changes in device performance due to temperature changes are minimal. Current readings obtained from the sensors are used to extract the shear stress component. Finite element simulations, using expected materials performance parameter information were also performed for similar packages and these results are compared to the measured results.

Studies of Magneto-Optical Recording in Multi-Magnetic-Layer Disk by Analytic and Simulating Approaches

1993 ◽  
Vol 313 ◽  
Author(s):  
Yoshiyuki Kawazoe ◽  
Xiao Hu ◽  
Shigeru Honma
Keyword(s):  
Computer Simulation ◽  
Magnetic Properties ◽  
External Field ◽  
Theoretical Estimate ◽  
Magnetic Layer ◽  
Magnetic Coupling ◽  
Optical Recording ◽  
Analytic Approach ◽  
Layer System

ABSTRACTThe effect of magnetic coupling in Multi-layer system is discussed by an analytic approach and computer simulation. The dependence of the enhancement of external field on the magnetic properties of the relevant materials is studied. Comparison between the theoretical estimate, simulation result and experimental observations are presented.

scholarly journals IMPROVED METHODS OF CALCULATING SPANS OF CITY BRIDGES DURING THE RECONSTRUCTION TAKING INTO ACCOUNT STRUCTURAL AND TECHNOLOGICAL FACTORS

2015 ◽  
Vol 1 (158) ◽  
Author(s):  
Alexey Lobiak ◽  
Armaіs Oganesyan ◽  
Maxim Kovalyov
Keyword(s):  
Computer Simulation ◽  
Concrete Slabs ◽  
Technological Factors ◽  
Linear Dependency ◽  
Reconstruction Scheme ◽  
Non Linear ◽  
Three Stages ◽  
Improved Methods

An improvement of the methods of computer simulation of beam spans bridge city during the reconstruction scheme of the device for concrete slabs invoice. The calculations provide consistent construction of structures in three stages with non-linear dependency of concrete deformation and creep.

scholarly journals Methodology to Measure the Benefits and Costs of Rural Road Closure: A Kansas Case Study

2012 ◽  
Vol 51 (1) ◽  
Author(s):  
Michael W. Babcock ◽  
Abhinav Alakshendra
Keyword(s):  
Population Density ◽  
Farm Size ◽  
Population Declines ◽  
The Road ◽  
Rural Road ◽  
County Population ◽  
Road Systems ◽  
Road Closure ◽  
Benefits And Costs ◽  
Road System

While rural roads are essential to state economies, increasing farm size and the corresponding increase in farm vehicle size coupled with declining rural population have stressed the rural road system. As county population declines the financial ability of counties to maintain and rebuild the road and bridge system isn’t keeping up with the rate of deterioration. If counties can’t maintain the rural road system as it currently exists, reducing the size of the system should be considered. The overall objective of the paper is to estimate the economic impact on selected county road systems from reducing the size of the system. The specific objectives include (a) for a sample of three Kansas counties, measure the benefits and costs of keeping the road system as it currently exists and (b) for the same sample of Kansas counties, measure the benefits and costs of several scenarios of county road closure. The main conclusion is that rural counties will be able to save money by closing some relatively low traffic volume roads and redirecting the savings toward increasing the quality of other county roads. Counties with relatively extensive road systems (miles of road per square mile) and relatively high population density are less likely to realize savings from road closure. In contrast, counties with less extensive road systems and relatively low population density are more likely to realize significant savings from closure of relatively low volume roads.

Weight Minimization of Natural Gas Distribution Riser Systems

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
M. S. Attia ◽  
M. M. Megahed ◽  
A. Gaber
Keyword(s):  
Natural Gas ◽  
Minimum Weight ◽  
Finite Element Models ◽  
Optimal Layout ◽  
Expansion Joints ◽  
Rule Based ◽  
Thermally Induced ◽  
Riser Pipe ◽  
Piping Systems ◽  
Value Decomposition

This study investigates the optimal piping layout in the installation of residential natural gas riser piping systems subjected to daily temperature fluctuations. Specifically, it is desired to evaluate the optimal safe configuration for minimum weight requirements in the absence of flexible expansion joints between the riser pipe and the branches. Structural optimization is carried out using fully parametric finite element models employing the singular value decomposition algorithm. Thermally induced stresses are examined to identify the optimal layout. The results indicate that the optimal piping layout satisfies strength requirements and achieves significant weight reduction and hence cost saving compared with existing, rule-based configurations.

EFFECT OF TRANSIENT THERMAL GRADIENT ON STRESSES IN COMPOSITE BRIDGES

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Caesar Abi Shdid ◽  
Omar El-Masri
Keyword(s):  
Thermal Gradient ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Concrete Bridges ◽  
Element Formulation ◽  
Expansion Joints ◽  
Thermally Induced ◽  
Heat Transfer Theory ◽  
Three Dimensional Finite Element ◽  
Concrete Deck

Composite steel-concrete bridges experience higher thermally induced stresses than their concrete and steel cousins. These thermal stresses which can result from support restraints, debris accumulating in expansion joints, or from non-uniform thermal gradients, can lead to significant damage in the concrete deck. Conventional heat transfer theory in solids, in three-dimensional finite element formulation, is used to perform a sequentially coupled thermal-stress analysis in a selected single-span case study bridge. Actual environmental boundary conditions for a selected geographical region are used to develop the thermal profile. The vertical thermal gradient is shown to be largely non-linear as opposed to existing models, such as AASHTO. The thermally induced tensile stresses in the concrete are shown to be significant compared to service load stresses and constitute 60% of the tensile strength of the concrete deck.

Comment—Revised estimates of the bias in the 'minimum number alive' estimator

1992 ◽  
Vol 70 (3) ◽  
pp. 628-631 ◽  
Author(s):  
Murray Efford
Keyword(s):  
Computer Simulation ◽  
Population Size ◽  
Coefficient Of Variation ◽  
Population Estimate ◽  
Negative Bias ◽  
Highly Sensitive ◽  
Minimum Number ◽  
Simulation Results ◽  
Open Populations ◽  
Minimum Numbers

The computer simulation results of Hilborn et al. (R. Hilborn, J. A. Redfield, and C. J. Krebs. 1976. Can. J. Zool. 54: 1019–1024) regarding the bias of the 'minimum number alive' estimator of population size are shown to be in error. Minimum numbers alive are approximately twice as biased as estimated by these authors: for five species of Microtus the negative bias is estimated as 24–45% instead of 10–18%. 'Minimum number alive' differs from the Jolly–Seber population estimate in being particularly sensitive to mean trappability when the coefficient of variation of trappability is constant. Both population estimators are highly sensitive to reduced trappability of unmarked animals. The Jolly–Seber estimator remains the method of choice for open populations, especially if the coefficient of variation in trappability can be minimized.

scholarly journals The Effects of Seasonal Thermal Loads at Expansion Joints Locations in Arabic Area Buildings

2019 ◽  
Vol 9 (1) ◽  
pp. 1919-1925
Keyword(s):  
Structural Deformation ◽  
Seasonal Temperature ◽  
Thermal Loads ◽  
Long Term Effects ◽  
Expansion Joints ◽  
Thermally Induced ◽  
Structural Engineer ◽  
Temperature Loads ◽  
Concrete Elements

Concrete buildings are subjected to fluctuation in seasonal temperature loads between summer and winter in the Arabic area. The long-term effects on buildings of such temperatures, along with the frequent fluctuation in the seasonal temperatures impose overall structural deformation, displacements, and alteration of stresses in concrete elements. The thermally induced deformations affect the serviceability conditions of buildings with time. Concrete creep and shrinkage will increase the cracks widths and the imposed stresses too. To eliminate this phenomenon effects, expansion joints should be provided. However, as per the buildings functions and trend to develop unique buildings by designers, joint-less buildings are usually the preferred option. When using this option, the structural engineer has to consider the effects of thermal loads changes in the design. Clear rules and standards must be provided to define the maximum joints spacing’s allowed length in addition to thermal study procedures. Different approaches are provided by researchers, each methodology provide different value for required joints spacing considering different aspects in design. In this paper I shall try to present three methods with comparison study for considered aspects and gaps for each method analysis to propose the most appropriate methodology as a tool helps engineers in calculating the maximum allowed spacing between expansion joints

Failures of Concrete Slit Drains, Caused by Negative Effect of their Erroneous Integration into Surrounding Multi-Layer Road Systems

2014 ◽  
Vol 587-589 ◽  
pp. 1152-1155 ◽  
Author(s):  
Petr Tej ◽  
Jiří Kolísko
Keyword(s):  
Numerical Analysis ◽  
Theoretical Analysis ◽  
Temperature Effects ◽  
Negative Influence ◽  
Thermal Expansivity ◽  
Concrete Slabs ◽  
Road Systems ◽  
Negative Effect ◽  
The Impact

Concrete slit drains (also known as slot drains) are being used for the draining of highways and roads, as well as for large handling and parking areas. Recently, this system of drainage has become increasingly applied, which does, however, bring with it an increased incidence of failures. The study concentrates on the failures of concrete slit drains, caused by the negative effect of their defective integration into surrounding multi-layer road systems. It starts with a theoretical analysis of the problem, i.e. the negative influence of thermal expansivity of surrounding concrete slabs on slit drains, the impact of their shrinkage, and the co-action of these factors. In addition, it presents a computer numerical analysis of a concrete slit drain loaded by the pressure of adjacent concrete slabs exposed to temperature effects and shrinkage. The most frequent stresses are modelled and the relevant results introduced.

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