Preface

A bridge is a structure built to span the physical obstacles without closing the way under‐ neath, such as a body of water, valley, or road, for the purpose of providing passage over the obstacle. Bridge engineering is an engineering discipline branching from civil engineer‐ ing that involves the planning, design, construction, operation, and maintenance of bridges to ensure safe and effective transportation of vehicles, people and goods. The book *Bridge Engineering* includes the main topics and the basic principles of bridge engineering and pro‐ vides the full scope of current information necessary for effective and cost-conscious con‐ temporary bridge. It reflects new engineering and building developments, the most current design methods, and the latest industry standards and policies. It provides a comprehensive overview of the significant characteristics for bridge engineering. It highlights the recent ad‐ vancements, requirements and improvements and details of the latest techniques in the global market. It contains a collection of the latest research developments on the bridge engi‐ neering. It comprehensively covers the basic theory and practice in sufficient depth to pro‐ vide a solid grounding to bridge engineers. It helps readers to maximize effectiveness in all facets of bridge engineering. This professional book as a credible source and a valuable ref‐ erence can be very applicable and useful for all professors, researchers, engineers, practicing professionals, trainee practitioners, students, and others who are interested in the bridge projects. The book *Bridge Engineering* consists of seven chapters.

*Chapter 1* reviews the maglev-elevated guideways. Contrary to the traditional railway trains, there is no direct contact between the maglev vehicle and its guideway. These vehicles travel along the magnetic fields that are established between the vehicle and its guideway. In con‐ trary to the traditional railroad tracks, there is no need for ballast, sleeper, rail pad, and rail fastenings to stabilize the rail gauge. Basically, there are two main elements in a maglev sys‐ tem including its vehicle and the guideway. The guideway is the structure that maglev vehi‐ cles move over it and are supported and guided by it. It is the main element in maglev system and holds a big share of costs for the system. The guideway consists of superstruc‐ tures and substructures. In fact, a guideway consists of a beam and two levitation rails. Guideways can be constructed at grade or elevated including columns with concrete, steel, or hybrid beams. Concrete guideway girders can be reinforced or prestressed. Majority of the existing maglev guideways are elevated and completely built on bridge. Guideway pro‐ vides guidance on the movement of the vehicle to support the vehicle load and transfer the load to the ground. The loading of the maglev vehicle is an important parameter in the prac‐ tical application. Guideway girder is evaluated for different load cases. During the past three decades, different guideways have been developed, constructed and tested.

*Chapter 2* explores the possibility of designing and constructing a super-long-span bridge with new materials in 2050. The features of this structure include the combination of suspen‐ sion and cable-stayed bridges, application of carbon fibre materials, extension of deck width, and pretension techniques. Linear static analysis, dynamic analysis and theoretical analysis are conducted under different loading cases. In linear static analysis, the stresses under criti‐ cal load combinations are smaller than the ultimate strength of the materials. However, the maximum deflection under the dead and wind load combination exceeds the specified serv‐ iceability limit.

In *Chapter 6*, several aerodynamic phenomena of relevance to long-span bridges are classi‐ fied and discussed. For certain cases, codes of practice recommend wind tunnel tests. The reader is introduced to these as well as to numerical simulations, which are currently gain‐ ing increasing importance. Next, measures for attenuating susceptibility for undesirable dy‐ namic responses are reviewed. The chapter ends with a discussion of the Vila Real Bridge deck-section based on wind tunnel tests and numerical simulations. The aerodynamics was effectively improved with geometrically subtle modifications that were proposed and

*Chapter 7* reviews the analysis of problems of highway and rail bridge dynamic response to moving traffic loads. Bridge vibration analyses comprise solution of many interdisciplinary problems. During the two last centuries, these problems have been studied by theoretical, numerical, and experimental way by many investigators. Therefore, the present chapter con‐ tains only the basic approaches for solving the complex problem of bridges subjected to dy‐

**Dr. Hamid Yaghoubi**

Iran

Preface IX

Director of Iran Maglev Technology (IMT)

adopted still in the design phase.

namic loading.

*Chapter 3* utilizes the artificial neural network (ANN) and multiple regression analysis (MRA) to model bridge condition rating based on the limited number of data sets. Bridge condition rating models are developed based on very limited inspection data records using MRA and ANN techniques. Since the data sets are limited, utilizing all the available data sets by handling missing data with the appropriate methods is expected to improve the per‐ formance of the models. Five methods are then used to handle the missing bridge compo‐ nent condition rating data. Three commonly used methods and two new methods are explored in this study. It seems that the performance of the model using data sets after han‐ dling the missing bridge component data to fill the gaps in the range scales of the bridge condition rating improved the performance of the model. Furthermore, a handling method that substitutes the missing data of bridge component ratings with available bridge rating data is the most reasonable.

In *Chapter 4*, structural identification (St-Id) is detailed and implemented to estimate the per‐ formance of the Bosphorus Suspension Bridge. In addition, certain efforts from finite ele‐ ment modeling (FEM) to utilization and decision-making for performance prediction are given based on each step of St-Id. In general, the St-Id concept is divided into two main parts: experimental and numerical investigations. Due to the high cost and time limitation for testing of long-span bridges, the most effective solution to the experimental research is SHM system (SHMs). For this purpose, the SHMs of the Bosphorus Bridge is considered and is more detailed on the basis of the bridge. As to numerical investigation, finite element modeling provides an extended solution from analysis to model updating of the bridges. Taking the considerations of the St-Id concept and the outcomes from the Bosphorus Bridge into account, structural performance of the bridge under extreme wind load and multipoint earthquake motion is estimated.

*Chapter 5* evaluates the recent advances in the serviceability assessment of footbridges under pedestrian-induced vibrations. Current international guidelines determine the effect of pe‐ destrians on footbridges through an equivalent harmonic load. However, the dynamic re‐ sponse of footbridges obtained according to these standards differs from the values recorded experimentally. In order to overcome this issue, a new modeling framework has been recently proposed by several researchers. This novel approach allows considering more accurately three key aspects: (i) the inter- and intra-subject variability, (ii) the pedes‐ trian-structure interaction and (iii) the crowd dynamics. For this purpose, different crowdstructure interaction models have been developed. Despite the large numbers of proposals, all of them share the same scheme: the crowd-structure interaction is simulated by linking two sub-models, namely, (i) a pedestrian-structure interaction sub-model and (ii) a crowd sub-model. Furthermore, the variability of the pedestrian's behavior may be taken into ac‐ count through the assumption that the model parameters are random variables. In this chapter, a summary of the state of the art of this new modeling framework is presented with a special emphasis in a case study, where the crowd-structure interaction model is used to simulate the lateral lock-in phenomenon on a real footbridge.

In *Chapter 6*, several aerodynamic phenomena of relevance to long-span bridges are classi‐ fied and discussed. For certain cases, codes of practice recommend wind tunnel tests. The reader is introduced to these as well as to numerical simulations, which are currently gain‐ ing increasing importance. Next, measures for attenuating susceptibility for undesirable dy‐ namic responses are reviewed. The chapter ends with a discussion of the Vila Real Bridge deck-section based on wind tunnel tests and numerical simulations. The aerodynamics was effectively improved with geometrically subtle modifications that were proposed and adopted still in the design phase.

sion and cable-stayed bridges, application of carbon fibre materials, extension of deck width, and pretension techniques. Linear static analysis, dynamic analysis and theoretical analysis are conducted under different loading cases. In linear static analysis, the stresses under criti‐ cal load combinations are smaller than the ultimate strength of the materials. However, the maximum deflection under the dead and wind load combination exceeds the specified serv‐

*Chapter 3* utilizes the artificial neural network (ANN) and multiple regression analysis (MRA) to model bridge condition rating based on the limited number of data sets. Bridge condition rating models are developed based on very limited inspection data records using MRA and ANN techniques. Since the data sets are limited, utilizing all the available data sets by handling missing data with the appropriate methods is expected to improve the per‐ formance of the models. Five methods are then used to handle the missing bridge compo‐ nent condition rating data. Three commonly used methods and two new methods are explored in this study. It seems that the performance of the model using data sets after han‐ dling the missing bridge component data to fill the gaps in the range scales of the bridge condition rating improved the performance of the model. Furthermore, a handling method that substitutes the missing data of bridge component ratings with available bridge rating

In *Chapter 4*, structural identification (St-Id) is detailed and implemented to estimate the per‐ formance of the Bosphorus Suspension Bridge. In addition, certain efforts from finite ele‐ ment modeling (FEM) to utilization and decision-making for performance prediction are given based on each step of St-Id. In general, the St-Id concept is divided into two main parts: experimental and numerical investigations. Due to the high cost and time limitation for testing of long-span bridges, the most effective solution to the experimental research is SHM system (SHMs). For this purpose, the SHMs of the Bosphorus Bridge is considered and is more detailed on the basis of the bridge. As to numerical investigation, finite element modeling provides an extended solution from analysis to model updating of the bridges. Taking the considerations of the St-Id concept and the outcomes from the Bosphorus Bridge into account, structural performance of the bridge under extreme wind load and multipoint

*Chapter 5* evaluates the recent advances in the serviceability assessment of footbridges under pedestrian-induced vibrations. Current international guidelines determine the effect of pe‐ destrians on footbridges through an equivalent harmonic load. However, the dynamic re‐ sponse of footbridges obtained according to these standards differs from the values recorded experimentally. In order to overcome this issue, a new modeling framework has been recently proposed by several researchers. This novel approach allows considering more accurately three key aspects: (i) the inter- and intra-subject variability, (ii) the pedes‐ trian-structure interaction and (iii) the crowd dynamics. For this purpose, different crowdstructure interaction models have been developed. Despite the large numbers of proposals, all of them share the same scheme: the crowd-structure interaction is simulated by linking two sub-models, namely, (i) a pedestrian-structure interaction sub-model and (ii) a crowd sub-model. Furthermore, the variability of the pedestrian's behavior may be taken into ac‐ count through the assumption that the model parameters are random variables. In this chapter, a summary of the state of the art of this new modeling framework is presented with a special emphasis in a case study, where the crowd-structure interaction model is used to

iceability limit.

VIII Preface

data is the most reasonable.

earthquake motion is estimated.

simulate the lateral lock-in phenomenon on a real footbridge.

*Chapter 7* reviews the analysis of problems of highway and rail bridge dynamic response to moving traffic loads. Bridge vibration analyses comprise solution of many interdisciplinary problems. During the two last centuries, these problems have been studied by theoretical, numerical, and experimental way by many investigators. Therefore, the present chapter con‐ tains only the basic approaches for solving the complex problem of bridges subjected to dy‐ namic loading.

> **Dr. Hamid Yaghoubi** Director of Iran Maglev Technology (IMT) Iran

**Chapter 1**

**Provisional chapter**

**Introductory Chapter: Modern Bridges**

**Introductory Chapter: Modern Bridges**

DOI: 10.5772/intechopen.74722

Bridge engineering is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of bridges to ensure safe and effective transportation of vehicles, people, and goods. Among transportation of vehicles, maglev (magnetic levitation) systems have become a focus of the worldwide transportation industries. The need for rapid transit systems has become vital in both urban and intercity travels. Application of magnetically levitated trains has attracted numerous transportation industries throughout the world. Contrary to the traditional railway trains, there is no direct contact between the maglev vehicle and its guideway. These vehicles travel along the magnetic fields that are established between the vehicle and its guideway. There are already many

In maglev guideways, contrary to the traditional railroad tracks, there is no need to ballast, sleeper, rail pad and rail fastenings to stabilize the rail gauge. Basically, there are two main elements in a maglev system, including its vehicle and the guideway. The guideway is the structure that maglev vehicles move over it and are supported and guided by it. It is the main element in maglev system and holds big share of costs for the system. It is vital for maglev trains. Guideway consists of superstructures and substructures. In fact, a guideway consists of a beam (girder) and two levitation (guidance) rails. Guideways can be constructed at grade (ground-level) or elevated including columns with concrete, steel, or hybrid beams. Concrete guideway girders can be as reinforced or prestressed. Majority of the existing maglev guideways are elevated and completely built on bridge (see **Figure 2**). Guideway provides

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Additional information is available at the end of the chapter

countries attracted to maglev systems (see **Figure 1**) [1–16].

**2. Maglev elevated guideways**

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.74722

Hamid Yaghoubi

Hamid Yaghoubi

**1. Introduction**

#### **Introductory Chapter: Modern Bridges Introductory Chapter: Modern Bridges**

#### Hamid Yaghoubi Hamid Yaghoubi

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.74722
