Condition assessment of several bridges in Sofia based on visual inspection and as-built drawings

2021 ◽  
Author(s):  
Alexander Jiponov ◽  
Lazar Georgiev
Keyword(s):  
Visual Inspection ◽  
Condition Assessment ◽  
Numerical Estimation ◽  
Bridge Management ◽  
Advantages And Disadvantages ◽  
Structural Types ◽  
Different Types ◽  
Bridge Structures ◽  
Existing Bridges ◽  
Condition Assessments

<p>Significant number of bridges in Sofia municipality are in halfway of their exploitation period – they are between 30÷60 years old. At the same time, there is a lack of common methodology for condition assessment of existing bridges (road, railway, pedestrian). Another issue is that there is no Bridge Management Data System, where the information from visual inspections, condition assessments and as-built drawings could be uploaded and used for further operations like regular maintenance activities, prioritization of repair works, planning budget and costs of the relevant authorities. Different structural types of bridge structures in Sofia are described in the paper. The advantages and disadvantages of the considered bridge types with respect to reliability and maintenance are analysed. Several bridges of different types are chosen in order to evaluate their condition based on visual inspection. Possibilities and advantages for implementation of condition assessment rating system based on numerical estimation are discussed.</p>

Influence of Reinforcement Corrosion on Reliability and Remaining Lifetime of RC Bridges

2016 ◽  
Vol 844 ◽  
pp. 89-96 ◽  
Author(s):  
Peter Koteš ◽  
Josef Vican ◽  
Martina Ivašková
Keyword(s):  
Reinforced Concrete Beam ◽  
Structure Design ◽  
Bridge Management ◽  
Bridge Management System ◽  
Actual Structure ◽  
Beam Elements ◽  
New Information ◽  
Bridge Structures ◽  
Negative Effect ◽  
Existing Bridges

The evaluation of existing bridge structures is the most important process in the global Bridge Management System (BMS) because of providing the basic information about existing bridges required from the viewpoint of decision making process related to the optimal bridge maintenance and rehabilitation strategy. The theoretical approach using conditional probability and the positive effect of the inspection was developed. The new information concerning the actual structure condition is used in this mathematical model. This information is not available in the process of the new structure design [1]. The work is focused on structures subjected to bending [2]. The reinforced concrete beam elements with or without degradation were investigated. The corrosion of reinforcement bars was used as material degradation. The biggest effect of the inspection was obtained for members, which do not degrade. Hereby, the negative effect of degradation on reliability index is also demonstrated.

scholarly journals Review on Computer Aided Sewer Pipeline Defect Detection and Condition Assessment

2019 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
Saeed Moradi ◽  
Tarek Zayed ◽  
Farzaneh Golkhoo
Keyword(s):  
Computer Vision ◽  
Visual Inspection ◽  
Review Paper ◽  
Condition Assessment ◽  
Machine Learning Techniques ◽  
Future Research ◽  
Infrastructure Management ◽  
Advantages And Disadvantages ◽  
Current State ◽  
Learning Techniques

Physical and operational inspection of sewer pipelines is critical to sustaining an acceptable level of system serviceability. Emerging inspection tools in addition to developments in sensor and lens technologies have facilitated sewer condition assessment and increased the quality and consistency of provided data. Meanwhile, sewer networks are too vast to be adequately investigated manually so the development of innovative computer vision techniques for automation applications has become an interest point of recent studies. This review paper presents the current state of inspection technology practices in sewer pipelines. An overall inspection tool comparison was conducted and the advantages and disadvantages of each method were discussed. This was followed by a comprehensive review of recent studies on visual inspection automation using computer vision and machine learning techniques. Finally, current achievements and limitations of existing automation methods were debated to outline open challenges and future research for both infrastructure management and computer science researchers.

scholarly journals Performance-Based Ranking of Existing Road Bridges

2021 ◽  
Vol 11 (10) ◽  
pp. 4398
Author(s):  
Ana Mandić Ivanković ◽  
Dominik Skokandić ◽  
Marija Kušter Marić ◽  
Mladen Srbić
Keyword(s):  
Traffic Safety ◽  
Performance Indicators ◽  
Damage Assessment ◽  
Visual Inspection ◽  
Condition Assessment ◽  
Structural Safety ◽  
Assessment Procedure ◽  
Bridge Condition Assessment ◽  
Existing Bridges

Bridge condition assessment in most European countries is based on visual inspection in combination with damage assessment of bridge components. For adequate bridge management, the assessment needs to be further developed to move from the bridge component level to the system functionality level and finally to the priority ranking level for repairs in the network. Although visual inspection provides only qualitative insights into bridge condition and cannot predict load-carrying capacity, it is still very often the only way to collect data on existing bridges and can provide very important information for evaluating structural safety, traffic safety, durability, and overall bridge condition. Therefore, this paper presents a unique procedure that establishes a relationship between a country-specific bridge condition assessment procedure based on visual inspection and the systematization of key bridge performance indicators developed within the European integrated management approach at three complementary and interrelated levels—component, system, and network levels. The assessment procedure for existing bridges initiates with damage assessment based on visual inspection of bridge components and runs through weighting at component, system, and network levels to the six most important key performance indicators (KPIs) for road bridges, which are organized as graphical and numerical inputs for ranking priority maintenance. These are bridge condition assessment, structural safety, traffic safety, durability indicator, availability, and the importance of the bridge in the network. The procedure is validated on a case study set of five real bridges, using the decision-making process as an example for the small sample size. The case study bridges differ in cross-section, type, and span (which vary from 9.5 to 72 m). The bridges were built between 1958 and 2001 and are located either on state or municipal roads in Croatia. The results, in terms of condition classification and priorities of future interventions within the representative group of bridges, justify the application of the described assessment procedure. Additional digitization efforts could easily implement the described assessment approach at the infrastructure network level.

Studies on Chemical Methods to Expose Gate/Tunnel Oxide and Identification of Gate/Tunnel Oxide Defects in Wafer Fabrication

2002 ◽  
Author(s):  
Y. N. Hua ◽  
G. B. Ang ◽  
S. Redkar ◽  
Yogaspari ◽  
Wilma Richter
Keyword(s):  
Acetic Acid ◽  
Silicon Oxide ◽  
Wafer Fabrication ◽  
Chemical Methods ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Capacitor Structure ◽  
Oxide Defects ◽  
Buffer Oxide Etchant ◽  
Etch Time

Abstract In failure analysis of wafer fabrication, currently, three different types of chemical methods including 6:6:1 (Acetic Acid/HNO3/HF), NaOH and Choline are used in removing polysilicon (poly) layer and exposing the gate/tunnel oxide underneath. However, usage is limited due to their disadvantages. For example, 6:6:1 is a relatively fast etchant, but it is difficult to control the etch time and keep the oxide layer intact. Also, while using NaOH to remove poly and expose the silicon oxide, the solution needs to be heated. It is also difficult to etch a poly layer with a WSix or a CoSix silicide using NaOH. In this paper, we will discuss these 3 etchants in terms of their advantages and disadvantages. We will then introduce a new poly etchant, called HB91. HB91 is useful for removing poly to expose the gate/tunnel oxide for identification of related defects. HB91 is actually a mixture of two chemicals namely nitric acid (HNO3) and buffer oxide etchant (BOE) in a 9:1 ratio. The experimental results show that it is highly selective in poly removal with respect to the gate/tunnel oxide and is a suitable poly etchant especially for removing polysilicon with/without WSix and CoSix in the large capacitor structure. Application results of this poly etchant (HB91) will be presented.

Optimum Seismic Zoning Using An Artificial Neural Network

2016 ◽  
Vol 32 (2) ◽  
pp. 1187-1207 ◽  
Author(s):  
Jaime García-Pérez ◽  
René Riaño
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Seismic Design ◽  
Seismic Zoning ◽  
Present Value ◽  
Total Cost ◽  
Structural Types ◽  
Initial Cost ◽  
Different Types ◽  
Artificial Neural

The Kohonen artificial neural network is employed to divide a region of known seismicity into zones. Optimum boundaries and seismic design coefficients for each zone are determined by computing the expected present value of the total cost, including the initial cost of structures and damages due to earthquakes. The region is discretized into cells containing information on seismicity and the number of structural types. Then regionalization is performed, first without considering jurisdictional limits and later including this restriction. Up to four different types of structures are considered simultaneously in the regionalization. The results are presented in maps showing both zones and corresponding seismic design coefficients.

Lexical-Grammatical Status and Lexicographic Presentation of Two-Component Stable Prepositional Combinations

2021 ◽  
pp. 32-51
Author(s):  
Elena V. Generalova ◽  
Keyword(s):  
Summary Table ◽  
Complex Issue ◽  
Dictionary Entry ◽  
Figurative Meaning ◽  
Advantages And Disadvantages ◽  
Unresolved Question ◽  
Two Component ◽  
Different Types ◽  
Syntactic Properties ◽  
Theoretical Issues

The aim of the article is to review the ways of dictionary presentation of stable prepositional combinations and the factors essential for their lexical-grammatical status and the type of optimal lexicographic description. The object of the study is twocomponent prepositional combinations with stable meanings and the “preposition+noun” structure. The material of the article is data of different dictionaries of Russian presenting stable prepositional combinations. In the course of the study, the following questions were answered: why the definition and interpretation of the lexical-grammatical nature of stable prepositional combinations are so difficult and ambiguous; what lexicographic interpretation these units have in dictionaries of different types; what the advantages and disadvantages of different ways of dictionary interpretation of such language material are. The following methods were used: introspective (observation, generalization, classification), systematic lexicographic description according to dictionary parameters, dictionary definition analysis. The summary table of the lexicographic presentation of stable combinations allows seeing both the unresolved question of dictionary interpretation of such units and the patterns of their interpretation depending on the type of a dictionary. As a result of the analysis the following conclusions were drawn. 1) In modern Russian there is a rather large (about 2,000 units) class of language units (prepositional combinations), the lexical-grammatical status of which is not defined, and there is no term for their definition; this class is historically formed and continues to replenish. 2) The type of dictionary presentation of stable prepositional combinations is determined by the dictionary concept, grammatical and syntactic properties, presence of figurative meaning and possibility of component variation of such combinations. 3) The unresolved theoretical issues have as a result the lexicographic discrepancy in the presentation of these language units. Extreme lexicographic solutions are a separate dictionary entry for each combination and the presentation of such units only as stable combinations in the entry of a noun (presented in academic explanatory dictionaries). 4) Taking into account only the factor of presence/absence of a gap seems to formalize the dictionary presentation of adverbs with both conjoined and split spelling, really existing in Russian, and the position of recognition of these units with independent words and their isolate presentation is not impeccable for dictionary users. 5) In the author’s opinion, the presentation of stable prepositional combinations exclusively as independent vocabules is inferior to the traditional lexicographic approach because the isolated presentation of this material breaks the semantic connections of these complex lexical units; the most complex issue is the differentiation of adverbs with split spelling and stable combinations.

Udziały jednostek samorządu terytorialnego w podatkach państwowych

Studia BAS ◽  
2021 ◽  
Vol 1 (65) ◽  
pp. 147-169
Author(s):  
Katarzyna Wójtowicz
Keyword(s):  
Fiscal Federalism ◽  
Final Section ◽  
National Income ◽  
Income Taxes ◽  
Local Revenue ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Fiscal Efficiency ◽  
Tax Sharing ◽  
Basic Features

The aim of this paper is to explore the rationale for the reform of the shares of local government units (LGUs) in national income taxes in Poland as well as to evaluate the selected proposals for changes in this area. The paper begins by outlining the definition and the basic features of tax sharing in the context of fiscal federalism. The next section provides an overview of the tax shares operating in some OECD countries. The main part of the article focuses on the key principles of the tax sharing system in Poland. The author briefly examines the fiscal efficiency of this source of local revenue in different types of Polish LGUs and the most significant dysfunctions of Polish local tax shares. The final section investigates the most important proposals for the reform of tax sharing and discusses their advantages and disadvantages.

Image-Based Comprehensive Maintenance and Inspection Method for Bridges Using Deep Learning

2018 ◽  
Author(s):  
Xuefeng Zhao ◽  
Shengyuan Li ◽  
Hongguo Su ◽  
Lei Zhou ◽  
Kenneth J. Loh
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Convolutional Neural Network ◽  
Visual Inspection ◽  
Health State ◽  
Bridge Management ◽  
Inspection Method ◽  
Maintenance Work ◽  
Maintenance And Inspection ◽  
Fine Turning

Bridge management and maintenance work is an important part for the assessment the health state of bridge. The conventional management and maintenance work mainly relied on experienced engineering staffs by visual inspection and filling in survey forms. However, the human-based visual inspection is a difficult and time-consuming task and its detection results significantly rely on subjective judgement of human inspectors. To address the drawbacks of human-based visual inspection method, this paper proposes an image-based comprehensive maintenance and inspection method for bridges using deep learning. To classify the types of bridges, a convolutional neural network (CNN) classifier established by fine-turning the AlexNet is trained, validated and tested using 3832 images with three types of bridges (arch, suspension and cable-stayed bridge). For the recognition of bridge components (tower and deck of bridges), a Faster Region-based Convolutional Neural Network (Faster R-CNN) based on modified ZF-net is trained, validated and tested by utilizing 600 bridge images. To implement the strategy of a sliding window technique for the crack detection, another CNN from fine-turning the GoogLeNet is trained, validated and tested by employing a databank with cropping 1455 raw concrete images into 60000 intact and cracked images. The performance of the trained CNNs and Faster R-CNN is tested on some new images which are not used for training and validation processes. The test results substantiate the proposed method can indeed recognize the types and components and detect cracks for a bridges.

Introduction of FECs and its Applications on Internet & Wireless Communications

2011 ◽  
Vol 403-408 ◽  
pp. 1776-1780
Author(s):  
Yan Ma ◽  
Chun Lan Ma
Keyword(s):  
Wireless Communications ◽  
Error Correction ◽  
Error Correction Coding ◽  
Advantages And Disadvantages ◽  
Coding Method ◽  
Different Types

This article focuses on FECs which is an error correction coding method and its applications in Internet and wireless communications. First, this article begins with the principles and the types of FECs. Then some typical applications n Internet and Wireless communications for each type of FECs are outlined. The next step is a comparison of the advantages and disadvantages between different types of FECs.

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