22 Longitudinally cracked pipes and their structural capacity

1982 ◽  
pp. 221-234 ◽  
Author(s):  
J. J. Trott ◽  
P. Nath ◽  
M. P. O'Reilly
Keyword(s):  
Structural Capacity

scholarly journals Modelling of Corrosion-Induced Concrete Cover Cracking Due to Chloride Attacking

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1440
Author(s):  
Pei-Yuan Lun ◽  
Xiao-Gang Zhang ◽  
Ce Jiang ◽  
Yi-Fei Ma ◽  
Lei Fu
Keyword(s):  
Service Life ◽  
Corrosion Current ◽  
Practical Experience ◽  
Concrete Cover ◽  
Premature Failure ◽  
Rc Structures ◽  
Structural Capacity ◽  
Cover Cracking ◽  
Deterioration Process ◽  
Cracking Process

The premature failure of reinforced concrete (RC) structures is significantly affected by chloride-induced corrosion of reinforcing steel. Although researchers have achieved many outstanding results in the structural capacity of RC structures in the past few decades, the topic of service life has gradually attracted researchers’ attention. In this work, based on the stress intensity, two models are developed to predict the threshold expansive pressure, corrosion rate and cover cracking time of the corrosion-induced cracking process for RC structures. Specifically, in the proposed models, both the influence of initial defects and modified corrosion current density are taken into account. The results given by these models are in a good agreement with practical experience and laboratory studies, and the influence of each parameter on cover cracking is analyzed. In addition, considering the uncertainty existing in the deterioration process of RC structures, a methodology based on the third-moment method in regard to the stochastic process is proposed, which is able to evaluate the cracking risk of RC structures quantitatively and predict their service life. This method provides a good means to solve relevant problems and can prolong the service life of concrete infrastructures subjected to corrosion by applying timely inspection and repairs.

scholarly journals Design and characterization of concrete masonry parts and structural concrete using repurposed plastics as aggregate

2019 ◽  
Vol 28 (1) ◽  
pp. 81-88
Author(s):  
Miguel A. González-Montijo ◽  
Hildélix Soto-Toro ◽  
Cristian Rivera-Pérez ◽  
Silvia Esteves-Klomsingh ◽  
Oscar Marcelo Suárez
Keyword(s):  
Structural Strength ◽  
Construction Materials ◽  
Tensile Tests ◽  
Compression Tests ◽  
Conventional Concrete ◽  
Structural Capacity ◽  
Plastic Type ◽  
Concrete Mix ◽  
Scientists And Engineers

AbstractHistorically known for being one of the major pollutants in the world, the construction industry, always in constant advancement and development, is currently evolving towards more environmentally friendly technologies and methods. Scientists and engineers seek to develop and implement green alternatives to conventional construction materials. One of these alternatives is to introduce an abundant, hard to recycle, material that could serve as a partial aggregate replacement in masonry bricks or even in a more conventional concrete mixture. The present work studied the use of 3 different types of repurposed plastics with different constitutions and particle size distribution. Accordingly, several brick and concrete mix designs were developed to determine the practicality of using these plastics as partial aggregate replacements. After establishing proper working material ratios for each brick and concrete mix, compression tests as well as tensile tests for the concrete mixes helped determine the structural capacity of both applications. Presented results proved that structural strength can indeed be reached in a masonry unit, using up to a 43% in volume of plastic. Furthermore, a workable structural strength for concrete can be achieved at fourteen days of curing, using up to a 50% aggregate replacement. A straightforward cost assessment for brick production was produced as well as various empirical observations and recommendations concerning the feasibility of each repurposed plastic type examined.

Autonomous Vehicle Safe Operating Speeds on the Automated Skyway Express in Jacksonville, Florida

2021 ◽  
pp. 036119812199183
Author(s):  
Andrew E. Loken ◽  
Joshua S. Steelman ◽  
Scott K. Rosenbaugh ◽  
Ronald K. Faller
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Physical Characteristics ◽  
Vehicle Stability ◽  
Conservative Method ◽  
Passenger Vehicles ◽  
Structural Capacity ◽  
Impact Angles ◽  
Unconventional Methods ◽  
Safe Operating

Autonomous vehicles (AV) differ significantly from traditional passenger vehicles in both their behavior and physical characteristics. As such, the validity of the guidance provided in the Manual for Assessing Safety Hardware, Second Edition (MASH 2016) is questionable in AV applications. Impact angles, speeds, and vehicle weights specified in MASH 2016 are inextricably linked to the traditional vehicles underlying the estimates. For AV applications, these parameters must be estimated from the ground up, stepping outside the guidance of MASH 2016. In this paper, a conservative method for evaluating existing infrastructure to support AV traffic is proposed. The method integrates traditional structural analyses with unconventional methods of estimating impact conditions. This methodology was developed for the Jacksonville Transportation Authority, who, when faced with unique challenges in maintaining and expanding their Automated Skyway Express, opted to convert the system from monorail to AV traffic. Leading AV developers were surveyed to develop a portfolio of potential candidates for the conversion. Estimated impact conditions were then compared against the capacity of the system’s existing concrete parapets. Ultimately, safe operating speeds for each AV candidate were recommended on the bases of structural capacity and vehicle stability. All but one AV candidate were deemed capable of safely operating at the desired speed of 25 mph without any modifications to the barrier. Although the methodology was developed for a particular case, it is applicable to future implementations of AVs on existing infrastructure, provided the roadway is confined similarly to the Skyway deck.

Full-Scale Experimental Evaluation of the Flood Resiliency of Thin Concrete Overlay on Asphalt Pavements

2021 ◽  
pp. 036119812110615
Author(s):  
Angel Mateos ◽  
John Harvey ◽  
Miguel Millan ◽  
Rongzong Wu ◽  
Fabian Paniagua ◽  
...  
Keyword(s):  
Structural Damage ◽  
Water Saturation ◽  
Critical Time ◽  
Structural Response ◽  
Extreme Weather Events ◽  
Pavement Materials ◽  
Structural Capacity ◽  
Weather Events ◽  
Pavement Structure ◽  
Falling Weight

The capacity to resist flooding is one of the critical challenges of pavement resiliency in locations subject to inundation. Flooding increases moisture contents, which weakens most pavement materials. Although the effect of moisture on the mechanical properties of most pavement materials is reversible, the structural damage caused by trafficking applied on the weakened pavement structure is not. The critical time for structural damage is typically after the flood and before “life-line” pavements have dried back when trucks are bringing in relief supplies and hauling out demolition. This fact, together with the increased occurrence of extreme weather events and sea level rise resulting from climate change, emphasizes the need to better understand the impacts of flooding on identified life-line pavements. This paper evaluates the flooding resiliency of thin concrete overlay on asphalt (COA) pavements by studying the effects that water saturation produces on the pavement structure. The research is based on the structural response and distresses measured in five thin COA sections that were instrumented with sensors and tested with a heavy vehicle simulator (HVS) under flooded conditions. The research shows that the flooding did not produce a noticeable change in the structural capacity of the COA, based on the structural response measured under the loading of the HVS wheel and the falling weight deflectometer, but did result in some structural damage to the asphalt base in some of the sections.

Damage Assessment of a continuous Hollow Core Deck Bridge subjected to ASR

2019 ◽  
Author(s):  
Konstantinos Tsiotsias ◽  
S. J. Pantazopoulou ◽  
Dimitrios Nikolaidis
Keyword(s):  
Synergistic Effects ◽  
Hollow Core ◽  
Element Analysis ◽  
Lower Face ◽  
Bridge Rehabilitation ◽  
Structural Capacity ◽  
Fine Aggregates ◽  
Chemically Induced ◽  
Extent Of Damage ◽  
Longitudinal Cracks

<p>An existing highway overpass located on a major motorway in Europe is examined on account of extensive longitudinal cracking on the lower face and sides of the deck, and signs of sustained damage in the piers. Material analysis reports have validated the existence of ASR activity in fine aggregates. The deck comprises a well reinforced hollow-core prestressed system, however longitudinal cracks penetrate to the interior of the hollow cores. The extent of damage is heavy considering that the laboratory values for free ASR expansion are below the threshold limits, suggesting that there may be underlying structural causes related to the response of the deck under traffic. Objective of the study is to interpret the reported damage, reproduce computationally the mechanics that led to the observed crack pattern and assess the residual structural capacity of the bridge. Detailed nonlinear finite element analysis is conducted to evaluate the structure and study the synergistic effects of structural demands, along with time-dependent phenomena and chemically induced expansion. The paper presents the numerical modeling and mechanistic evaluation of the findings through sensitivity analysis of various scenarios considered to reproduce the state of damage and to assess the effectiveness of various retrofitting strategies considered for bridge rehabilitation.</p>

Submarine Impact With the Oseberg Jacket

1992 ◽  
Vol 114 (1) ◽  
pp. 1-8
Author(s):  
T. C. Thuestad ◽  
F. G. Nielsen
Keyword(s):  
Time Series ◽  
Initial Level ◽  
Progressive Collapse ◽  
Structural Safety ◽  
Acceleration Time ◽  
The North ◽  
Structural Capacity ◽  
Collapse Analysis ◽  
The North Sea ◽  
Progressive Collapse Analysis

The Oseberg jacket was installed at the Oseberg field in the North Sea during the summer of 1987 and the production started on December 1, 1988. On March 6, 1988, a submarine accidentally impacted with the Oseberg jacket. This paper presents results from the evaluation of the importance of the damage to the overall structural safety. A nonlinear progressive collapse analysis is applied for the safety check. The theoretical computations are verified through evaluation of strain and acceleration time series recorded during the submarine impact. The reduction in the overall structural capacity of the jacket was in the order of 10 percent. However, the local member capacity was significantly reduced and it was necessary to remove the damaged member in order to obtain the initial level of safety.

scholarly journals Influence of Prior Distributions and Fragility assessment methods in the estimation of the Magnitude of a Historical Seismic Event

2018 ◽  
Vol 149 ◽  
pp. 02038 ◽  
Author(s):  
Eduardo Charters Morais ◽  
László Gergely Vigh ◽  
János KrÄhling
Keyword(s):  
Stone Masonry ◽  
Fragility Functions ◽  
Backbone Curve ◽  
Prior Distributions ◽  
Magnitude Distribution ◽  
Structural Capacity ◽  
Capacity Spectrum ◽  
Distance Distributions ◽  
Dynamic Methods ◽  
Modelling Strategies

The production of fragility functions describing the probable behaviour and damage on historical buildings is a key step in a method for the estimation of the magnitude of historical seismic events that uses a Bayes'. The fragilities are estimated by integrating the structural capacity with the seismic demand using either static methods, as the Capacity Spectrum Method (CSM), or dynamic methods, as Incremental Dynamic (IDA) and Multiple Stripes Analysis (MSA). Uncertainties in both resistance, demand, and distance and magnitude models propagate to the posterior magnitude distribution. The present paper studies the effect of uncertainties related both to the production of fragility functions and prior distributions, in the estimation of the magnitude of the 1763 Komárom earthquake (in historical Hungary). In the XVIII century most of the structures in the region were built of earth, adobe, clay or stone masonry, which is complex to model. While micro or detailed macro-modelling strategies are computationally costly, simplified macro-approaches are often more efficient, but require a pre-identification of the failure mode(s) and the determination of the backbone curve. For this study, a simplified macro-model of a Hungarian peasant house archetype is calibrated for CSM and IDA. The physical and geometrical uncertainties are incorporated in the fragilities using Monte-Carlo simulation. Prior magnitude and distance distributions are studied. The final magnitude estimates are presented and discussed.

Seismic Performance Evaluation for Steel Reinforced Concrete Frame Structures

2011 ◽  
Vol 255-260 ◽  
pp. 2421-2425
Author(s):  
Qiu Wei Wang ◽  
Qing Xuan Shi ◽  
Liu Jiu Tang
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Seismic Performance Evaluation ◽  
Steel Reinforced Concrete ◽  
Concrete Frame ◽  
Structural Capacity ◽  
Reinforced Concrete Frame Structures ◽  
Dynamic Nonlinear Analysis

The randomness and uncertainty of seismic demand and structural capacity are considered in demand-capacity factor method (DCFM) which could give confidence level of different performance objectives. Evaluation steps of investigating seismic performance of steel reinforced concrete structures with DCFM are put forward, and factors in calculation formula are modified based on stress characteristics of SRC structures. A regular steel reinforced concrete frame structure is analyzed and the reliability level satisfying four seismic fortification targets are calculated. The evaluation results of static and dynamic nonlinear analysis are compared which indicates that the SRC frame has better seismic performance and incremental dynamic analysis could reflect more dynamic characteristics of structures than pushover method.

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