PSI - Issue 64

Haider Mraih et al. / Procedia Structural Integrity 64 (2024) 1402–1410 Haider Mraih/ Structural Integrity Procedia 00 (2019) 000–000

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1. Introduction During their lifetime, structural members can be exposed to various types of loading, including impact. The unique characteristic of impact load is the large amplitude with a short time, causing the strain rate effects on the materials and causing the structure's inertia effect. Thus, the behavior of the structure can be significantly different under impact load compared to static (Xiang and Bin, 2012). The impact loads can be generated from various sources, such as rocks falling on bridges in the mountain areas, wind gusts, objects, vehicles, and vessel impact. In particular, the impact of over-height vehicle collisions with bridge girders was noticed in recent continuous growth worldwide with less attention in the literature. This type of incident arises when large trucks exceeding the permissible clearance height of highway bridges collide with the lower portion of the bridge girder (Figure 1- a: repair costs around $1 Million (Stateline, 2019)). The consequences of such collisions can be catastrophic, leading to extensive damage to both the vehicles and the bridge components. For reinforced concrete girders, the bottom end of the bridge girder may become dislodged, severely compromising the strength and durability of the entire beam due to exposure of steel reinforcements to environmental elements and subsequent corrosion. In critical instances, a high-impact load can precipitate an immediate collapse of the bridge girder, giving rise to substantial safety and economic ramifications. In the United States, over-height vehicle collisions contribute to approximately 61% of bridge impairments (Hite, 2007), while in Beijing, China, over-height vehicle-related damages account for an estimated 20% of overall bridge deterioration (Nguyen and Brilakis, 2016). Further, Jing et al. (2023) stated that over-height vehicle collisions with bridge superstructures in the United Kingdom increased from 729 to 1870 in four years (1990-1994). Given the escalating global traffic volume, the frequency of such incidents continues to rise.

Figure 1. Impact source and solution: (a) impact event- Nashville- USA (Stateline, 2019); and (b) various FRPs types (Al-Saadi et al., 2019).

Fiber-reinforced polymers (FRPs) have shown promise in improving structural elements' load-bearing capacity, ductility, and overall resilience. However, their specific effectiveness in mitigating impact loads is still under investigation. With various FRP materials available (as shown in Figure 1-b), assessing and selecting the most suitable strengthening material for mitigating impact loads is essential. This involves studying the FRPs' ability to dissipate impact energy effectively and their performance under dynamic loading conditions. Evaluating the practicality and compatibility of these strengthening materials with existing bridge girder systems requires a thorough assessment. Therefore, this review aims to consolidate and discuss existing research on the application of strengthening materials to mitigate impact loads from vehicle collisions. It presents the structural performance of members strengthened with different FRPs, highlighting differences in energy absorption, failure modes, and maximum applied load targeting to identify the most effective composite materials against impact.