# Analysis of Bridge Tests on Sandy Overburden Site with Fault Dislocating
###### Abstract  
Performance-based seismic design methods for bridges are advancing, yet limited research has explored the damage mechanisms of bridges subjected to extreme seismic effects, such as those near or across faults. To investigate the damage mechanisms under bedrock dislocation and bridge rupture resistance, providing essential insights for the standardized design and construction of bridges in close proximity to seismic rupture sites, we developed a large-scale device to model bridges in the immediate vicinity of tilted-slip strong seismic rupture sites. This included a synchronous bedrock dislocation loading system. Four sets of typical sandy soil modeling tests were concurrently conducted. The results indicate: (1) The overall shear deformation zone of the foundation and surface uneven deformation primarily concentrate the overburdened soil body along the fault dip. The damaged area under the low-dip reverse fault is lighter on the surface and inside the soil body compared to the high-dip-positive fault. (2) The presence of bridges reduces the width of the main rupture zone and avoidance distance to some extent. However, this reduction is not as significant as anticipated. The damage to the bridge pile foundation along the fault dislocation tendency notably leads to the bending damage of the bridge deck. (3) Input parameters for fracture-resistant bridge design (surface rupture zone location, extent, maximum deformation, etc.) can be deduced from the free site. Within the rupture zone, a \"fuse\" design can be implemented using simply supported girders. Additionally, combining the \"fuse\" design with simple supported girders on both sides and utilizing simple support beams for \"fuse\" design within the rupture zone, along with structural \"disconnection\", allows for reinforcing measures on the bridge structure's foundation platform and pile in the soil body. strong earthquake surface rupture; model test; bridge; sand covering layer; bedrock dislocation +
Footnote †: journal: Applied Sciences  
1  
[PERSON], [PERSON], [PERSON], J. Analysis of Bridge Tests on Sandy Overburden Site with Fault Dislocating  
Dislocations. Appl. Sci.2024148522  
was impacted by a fault, leading to the total collapse of the northernmost section and the descent of girders on the remaining three spans [7, 8]. During the 2008 Wenchuan earthquake in China, with a magnitude of Ms8.0, the Xiaoyudong Bridge and the Yingxiu Shunhe Bridge near the fault zone collapsed due to fault displacement during the earthquake. The bottom of the pier of Baihua Bridge [9] has crushing failure, and the bottom of the pier and the tie beam have severe shear failure [10]. The 2010 Chilean earthquake, measuring M8.8, inflicted severe damage on several bridges, among them the San Antonio Bridge and the Loncomilla Bridge, situated on the normal fault [11]. During the 2011 Christchurch earthquake in New Zealand, with a magnitude of M6.3, the Lyttleton Port Bridge, traversing a fault, experienced extensive damage to its primary structure due to surface rupture induced by the powerful earthquake [12]. Regulations governing bridges in different countries, including \"Canada's Canadian Highway Bridge Design Code [13]\", the United States \"Handbook for Seismic Reinforcement and Renovation of Highway Structures [14]\", China's \"Guidelines for Seismic Design of Highway Bridges [15]\", \"Railway Engineering Seismic Design Code [16]\", and \"Highway Bridge Seismic Design Code [17]\", generally emphasize the prohibition or avoidance of active faults and their associated seismic fracture zones. Nevertheless, for critical infrastructure like bridges with extensive longitudinal spans, challenges arise from constraints like terrain, topography, construction expenses, active fault detection technology, and calculation theories. Prohibiting or avoiding them alone cannot entirely mitigate the risk of damage to bridges spanning or adjacent to the surface rupture zone of seismic faults [18, 19].