Introductory Chapter: Design, Construction, and Retrofit of Bridges, Roads, and Highways

*Khaled Ghaedi, Meisam Gordan, Ahad Javanmardi, Hamed Khatibi and Ramin Vaghei*

## **1. Introduction**

Bridges are structures designed to support traffic and other dynamic loads induced by vehicle loads to pass through natural or manmade obstacles. Types of pathways may be roads, highways, railroads, pipeline waterways, or pedestrians. Obstacles can be categorized as canals, rivers, mountains, valleys, lakes, seas, and other manmade structures, such as buildings, rail lines, roads, and bridges themselves. A bridge is a vital structure of modern roadway and railway systems and largely serves as the lifeline of public infrastructure. Apart from bridge structures, Roads and highways are commonly considered important to new-fashioned life and they play an important role in the advancement of cities. The lack of quantifiable sustainability methods creates gaps in sustainability knowledge, leading to the public, and environmental and financial dissatisfaction with completed highways and urban roads. This chapter discusses the key points in design and construction assessment of bridges, highways, and roads covered in the present book in order to bridge the knowledge gap. The discussed topics such as bridge optimization techniques, risk assessment of roads, highway management systems, and challenges in highway construction presented in the book chapters help to provide insights into the bridges and roads' impacts on the environment and the benefits of adopting development assessment systems to increase safety of bridge structures, roads, and highways.

#### **1.1 Challenges and solutions**

Civil structures and infrastructure, in particular roadways and bridges, have multiple lifelong obstacles caused by various reasons of environmental impact such as corrosion, microstructural defects, cracks, thermal and residual stresses, instability, bond failures, or natural disasters such as earthquake and flood [1–3]. Damage to structural elements affects structural properties such as mass, stiffness, and damping, resulting in changes in the dynamic response of the structure such as natural frequency, modal shape, and damping ratio [4–9]. Therefore, actual solutions can play an essential role in ensuring the safety and reliability of structures. In recent decades, the advancement of road and bridge structures along with their optimization in design and construction has attracted much attention. Development and structural optimization based on mathematical and numerical analysis have resulted in strategies

#### **Figure 1.**

*Bridge strengthening with (a) CFRP plates, (b) CFRP strips and (c) CFRP sheets [19].*

applied primarily for fruitful and sustainable design in road and bridge construction [10–17]. For instance, the strength of bridge elements can be significantly increased using Carbon fiber-reinforced polymer (CFRP) composites due to their outstanding performance [18]. **Figure 1** shows a few examples of bridge strengthening using CFRP. As mentioned, new tools and technologies can also be adapted to design new bridges and assess and retrofit existing bridge structures [20, 21]. **Figure 2** shows the utilization of advanced tools and techniques in damage assessment of a slab-on-girder bridge structure utilizing the structural health monitoring (SHM) approach.

Roads, as another important traveling pass, provide a means to communicate between cities or even countries. They can be designed as a one-lane road or a multiple-lane road that aligns or intersects with each other. During construction, different requirements have to be made to provide an effective solution. One of those requirements is road drainage systems in order to maintain the structural integrity of the roadway [22]. This measure guarantees road usability and sustainability over the long term. Drainage channels on one or both sides of the road provide a means of harmlessly diverting outflows from road surfaces and neighboring facilities to artificial or natural drainage channels [23]. **Figure 3** depicts examples of drainage systems for roads and highways.

Inappropriate slope stability can lead to road drainage problems and cause road damage. Material flowing to the channel bottom may block the flow of water into the channel and cause water to leak into the road body. This causes discrepancies and shoulder deformity. **Figure 4** demonstrates how an unstable raceway slope fills the

*Introductory Chapter: Design, Construction, and Retrofit of Bridges, Roads, and Highways DOI: http://dx.doi.org/10.5772/intechopen.105507*

#### **Figure 2.**

*SHM technique to detect bridge damages using vibration test method as (a) schematic view and dimensions of the slab-on-girder bridge, (b) experimental setup of the test and (c) the arrangement of the accelerometers and the excitation point.*

**Figure 3.** *Drainage systems.*

bottom of the channel and causes an annual increment in road surface settlement. Furthermore, **Figure 5** shows unlined channels that cause severe destruction to the channel in the form of silting and washout.

Despite extensive data, recent developments in structural design, construction, and retrofitting have not yet been fully explored. Therefore, the main purpose of this book is to review past studies on bridges, highways, and roads to provide a detailed investigation in order to come up with reasonable solutions for existing challenges in design and construction using advanced methods and technologies. It also helps engineers better understand designing new bridges, roads, and highways, and retrofitting techniques for previously constructed of such systems. This book also proposes a sustainable drainage system for road construction.

#### **Figure 4.**

*Unstable raceway slope fills the bottom of the channel and causes an annual increment in road surface settlement.*

**Figure 5.** *Road channel fracture due to lack of proper slope angle.*

*Introductory Chapter: Design, Construction, and Retrofit of Bridges, Roads, and Highways DOI: http://dx.doi.org/10.5772/intechopen.105507*
